I'll see if I can reach it from the back. I need a reason to knock the cobwebs off it haha.

I do have the poly engine and tranny mount that raise it a bit from what new oem rubber mounts would be.

I will say thou, I had drive shaft vibrations for years with my 91 z28. it was a t5 car too with all oem suspension and it wasn't till I gave up on replacement u joints or having drive shafts made from local shops that I got it fixed. that oem junk yard shaft from a v6 car fixed mine completely. I know you can't really do that with your different yoke but if the angle is close. I still put my money on it being shaft related.


edit to say it had stock springs on it. sagging from age but it wasn't lowered. it vibrated like crazy at about 70mph and up from the day I got it with about 35k ish miles on it back in 93ish. I got it used and it still had a month or 2 of warranty left on it and gm didn't even fix it. they just kept saying can't recreate problem. said their tech couldn't go above the speed limit to test drive haha.

 

so this probably won't help much but I can't reach the drive shaft from under the back either, I must be getting fat haha and I forgot it's aluminum. but there's a flat spot on the diff, so I zeroed it on the ground and stuck it to that and then the balancer in the front.






man look how bad the webs are on the back side of the tire. I sware I just backed it out and washed it a month or 2 ago. ugh. I gotta clean this poor thing up and get the ebl swapped into it.
and spray everything down with bug spray haha.

 

Interesting for sure. You appear to be setup right about close to what is prefered. Your crankshaft is front to back down 3* and your pinion is front to back down 2*. So you have 1* "preload" for the expected rotation under torque to bring them parallel. It is good to know your crank is at 3* though. That gives me a good comparison for that. With the TKO I am out of room to raise the back of the transmission anymore without beating the **** out of the trans tunnel. So I have to get my pinion angle under control to get things in a better direction.

 

the corvette guys have spacers they out under the engine cradle to lower it for different reasons. I don't know how close you are but maybe could lower the engine a 1/4in gain some tilt?

 

I would likely try going back to rubber engine mounts before I went that route. That would let the engine settle a little bit more I think over the poly mounts. My 4th gen rear spring isolators are arriving today and I am hoping to be picking the car up tonight too if they call to let me know its done at the exhaust shop.

Good news bad news I forgot to mention. Monday my buddy followed me to the shop to give me a ride home and said there wasn't any smoke coming from the exhaust pipes. Even when I got on it a few times on the interstate. So maybe my valve guides or seals aren't shot like I had previously thought. That's the good news. The bad news is I believe I had excessive crankcase pressures due to my changes I made to my PCV system and grommets going into the valve covers. I don't think they were flowing enough air to evacuate the crankcase pressures because I had my dipstick push up twice on me during hard acceleration resulting in a smoke screen from the oil spraying out. Worth noting I have no apparent blowby even with the PCV valve removed, so I don't think it is being caused by that. I made a few changes to the grommets and threw a new dipstick in (rubber seal was missing) before driving to the shop that day. Checked the dipstick at the shop and it hadn't moved but did seem to have a lot of drips under the car when we got it up on the lift. Was too busy explaining the exhaust system that I didn't try to find the source but I fear I might've blew a seal out somewhere. Really hoping it isn't the rear main.

 

Shop finished up the exhaust and picked it up last night. Well worth the $200 charge. Heck that is ~2.5hrs of my labor rate, and I know I couldn't have done it that quick even if I wanted to. Gained exhaust clearance where the Y-Pipe joins behind drivers tire. My wideband seemed to be reading a lot better with the fixed leaks. My "false" knock counts even seemed reduced a little, probably due the exhaust pipe that was touching the panhard bar support at the rear being fixed. I am going to pull the wideband sensor and do a free air calibration just to be good. In closed loop cruising down the highway at 70mph it was a very consistent average around 15.2. Which is a dead even point above my commanded stoich AFR of 14.2 for E10 fuel. Hoping a free air calibration sorts that. Will also confirm my LC2 controller is setup correctly to the 10:1=0V 20:1=10V that my gauge uses and EBL is set to. I know default on the LC2 is a bit funky/random values.

Regarding the oil leak, they did mention on the phone they thought it was coming from the valve cover gaskets. Next time I get a chance to work on the car I will be taking a look at that. I've had them off several times in recent history when doing the PCV system changes. Maybe I had them shifted some this last go around.

I received my 4th gen rear spring isolators as well. Need to get them installed so I can hopefully nip this driveline alignment in the butt once and for all. I can tell my settings are closer than they've been because my vibration gets worse on decel at higher speeds. Which is proof the pinion angle is close to right under power but further from where it needs to be on decel due to the axle rotation on accel/decel. It starts as a harmonic vibration around 70mph that worsens with speed to the point of constant vibration above 80mph.

 

I was just out logging my ls3 a 2 days ago and at idle the wide bad doesn't match the narrow bands either. it's almost a full point high. it's can stuff so no offsets to worry about. as soon as you get the rpms up and cruise even to 1200 it comes right inine with the narrows and you can watch it swing right with them.

so yeah, I think it's just a wide band thing to read a bit leaner at idle, especially with a cam.

fingers crossed for the vibration.

 

I hit on the WB deal in the thread I posted over on DIY Prom. Think I have it figured out. Was a combination of two issues. One being the WB controller reporting 14.7 as Lambda 1.0 and the tune/fuel having a stoich lambda of 14.2. Second "issue" was my o2 mV targets were richer than stoich at idle and leaner than stoich at cruise kpa. Reset my LC2 controller to report correctly and adjusted my WB settings in EBL to match. Looking back at the same datalog my idle was actually at about 13.8 and my cruise was about 14.7. Glad I found that stoich mismatch. I am going to try the o2 targets I posted in that thread next time I drive it to see how it does. Looking like I've got a really busy weekend with jetski winterizations coming up so might not get a chance to do anything this weekend with the car. Will try to get the spring isolators installed and take a look at that oil leak if I get time.

 

I didn't think about the narrow bands auto correct kinda to whatever fuel you run.

I really wish I'd have started tuning thinking in lambda, seems to avoid all that. but my brain just can't keep the numbers straight.

on that note, so narrow bands find stoich of say e10 and put our 500mv at 1 lambda which is 14.1 but we don't need to change the target in the ecm cause it doesn't know any better, it's chasing 500ma in close loop anyways. but wide band reads 1 lambda with e10, we selected gas in the drop down box, so does math and spits out 14.7 on the screen instead of 14.1?. is that what's going on?

I forgot about the free air cal. been a while since I messed with my lc-1.

 

To answer your question, you are basically right on the ECM is doing in closed loop. But 450mV is "middle" on the narrow band. Which to that point, the base tune I was using didn't technically even have 450mV thresholds. Idle was slightly richer (higher mV) and cruise was slightly leaner (lower mV) from 450mV. I have adjusted them to try a scale that makes more sense. Leaner at low load and richer at high load. I feel like I have a good understanding of the whole lambda thing but I am still not 100% convinced on my WB output lol. When going in and making the changes to the LC2 programming you can select fuel type. That tells it what "lambda" is at 1.0. Then it creates a scale to use for the 0V=AFR and 5V=AFR values based off that. The default 14.7 values are 0V=7.35 and 5V=22.39 putting 14.7 at about 2.44V. If you change to a custom fuel (E10 wasn't a preset option) it creates a scale that is 0V=9.66 and 5V=19.33 with 14.2 being 2.35V and 14.7 now being about 2.61V (interpolating). So the old voltage of 2.44V=14.7 is now 2.44V=14.4V...

So my confusion now is, is this all a wash? Am I fussing too much over it being "perfect"? As long as my closed loop is targeting "stoich" and my PE/WOT AFRs are in the mid twelves then I should be fine. I am not racing so does being at 12.3 vs say 12.6 AFR at WOT really going to be a make or break thing? I guess time will tell. I didn't have time to mess with car tonight so haven't even started it since any of these changes.

 

ahh I do remember the adjustable output scale on my old lc-1. I was using one as a narrow band simulator and moved it some to make the car run a little richer at idle, since it was smoother and I didn't have a cat to worry about. this was forever ago thou, I know now it could be done in the tune with the offsets. I also forgot 450mv was the middle, but makes sense.


I honestly wouldn't get to caught up chasing exactly the spot on aft unless you end up on a dyno and even then, fun to drive is the point of it all. If I remember right, low 12s at peak tq and mid to high 12s at peak hp was a rule of thumb? I also remember grumpy on this site preaching use what makes it run happy. without a cat they seem to like running a touch rich at idle, especially with a cam. it doesn't really hurt mpg anyways, and then if it's happy I believe ebl has highway mode to engage and save some fuel mileage anyways with lean cruise.


I seem to remember my lc1 was bad about voltage offsets and the trick was to get the USB cable and software to show the af over the can or whatever data transfer it uses, on the laptop screen and then adjust your offsets so that the a/f matches that on tunerpro logs?

on a side note, I think I finally have my injector issues solved and the flex fuel 52s finally setup right on my obd2 car, so I can be out driving it around and move this poor neglected formula to the side of the garage that stuff gets worked on. reading along your thread is good motivation.


​​​​

 

I feel that you could "chase" A/F ratio for infinity....
I think your take on it being "good enough" is....good enough.

 

Good deal, sounds like I am on the right path then with the AFR/WB. The WB settings are set with my fairly extensive researched understanding of where they should be for E10 fuel so I will run with them. My gauge reads almost half a point lean compared to the WUD live data, but I am cool with that. Rather it read lean than rich.

I was able to accomplish what I needed out in the shop Saturday and we didn't have much else to do so I was able to bring the car into the garage to do a little work. Got the 4th gen rear isolators installed. Didn't gain as much height in the rear as I thought I would, I guess I just need to suck it up and get new springs all around. Wish the ground controls weren't so expensive cause those would be sweet to have. I'd love to raise it *just* enough to eliminate my vibrations and help with ground clearance. Because aside from those issues I love the stance.

On the oil leak front, I looked at the valve cover gaskets and repositioned them a little bit. It seemed like the fitment on the back drivers head wasn't the best however I've ran these steel rubber coated felpro gaskets for years now with no issues prior so not too sure what's up. I took it for a drive after all of that work and the vibration seemed to be pushed up 5mph or so before it starts getting bad. So I am on the right track with things. My closed loop tune is really starting to progress. I've even started making some acceleration enrichment adjustments. If I get on the throttle while holding >2000 rpm it seems to be really dialed in. Need more AE pulled at lower rpm as it is dropping AFRs before settling back in where it should be. Once I got back home I looked under the car to see what the leak situation was like. Was still dripping. With the engine still running I pulled the PCV valve and the little piece of foam that came with the "baffled" grommets was stuck to it. So I removed the foam piece and the PCV started rattling & doing its thing again. Thinking maybe that foam was keeping it from working. Hopefully I am getting closer to figuring this leak out.

 

I've ordered new coil springs for the car. I've got the car up on stands right now but on my wifes side of the garage...so hopefully they arrive fairly quickly. I crammed her car on the other side between jetskis lol will see how long I can keep that up this week before I start getting questioned. I've got election day off tomorrow so in theory should be able to pull the old springs and get it ready for a quick install once they arrive.

Going to throw new valve cover gaskets on it as well. Can't seem to get a good seal on that drivers side valve cover.

 

Well I FINALLY made some real progress on the vibrations. I got the rear springs installed over the weekend. Was still recovering from being a little sick so didn't get to the front. Took it for a drive after and still had vibrations. My driveline angles had improved with the raised rear, was really thinking that was it...

Fast forward to Tuesday I spent a lot of time reading up more and more on this issue. Even over on ls1tech with the 4th gen guys. Got reading about poly transmission mounts. Apparently a lot of individuals have issues with the Energy Suspension unit. Well guess what poly mount I have?
So I stopped in Oreillys to see if they had a factory rubber replacement on hand. For $8 I had one in hand. Got it installed tonight and took it for a drive. Smoothest this car has felt in YEARS! It was dark and misting so didn't get up too high of speed but up to 60mph it was smooth as silk. Hit mid 70s for a brief second and didn't feel much of any vibrations. Nothing like before. Will try and get a real test run done on the interstate soon. Still have some clunking that I think it torque arm related. But I am beyond happy with the results! I am hoping with a cross member mounted torque arm I won't have issues with a rubber mount ripping. Time will tell.

While I was under the car I noticed the torque arm front mount plates were cut down some on top for clearance for the transmission. Looking at UMI website the torque arm mount plates have 3 holes. I am starting to think this is why I couldn't get enough adjustment out of the torque arm to get my pinion pointed up where it needs to be. The previous owner of the torque arm setup must have had clearance issues and used the lower bolt hole and cut the rest of the plate down for clearance. I ordered two new plates from UMI to see if I can't make it work correctly with the top hole. It looks like I will have clearance issues too but I will do what I can to make it work. Here is a photo showing the plates.

 

you know what, your post just reminded me. this formula has a tranny cross member I had never seen before. my 91 z28 was a factory manual car too, and it had a normal looking single piece cross member, I fought vibrations with it from day one, even with rubber mounts, I did switch to poly. so this 90 formula I have now has a 2 piece cross member that has a center piece that raises the tail housing higher. while it did come with a aluminum drive shaft when I got it, I don't know if it was stock, but this car has always been vibration free.


it looks like this one.. I have no idea of that plays into your pinion angle measuring

https://www.ebay.com/itm/30506537492...mis&media=COPY

 

In my reading I did see something about a 2 piece cross member. Also read something about a fluid filled transmission mount. Definitely never seen one in person though, looks like a interesting piece. Back when I was still running the T5 I had just the typical 1 piece cross member. I can't remember if I went to the poly when I swapped transmissions or earlier. Was back in like 2015 when I did that swap so I've slept a few times since then.

Honestly if I can get this final clunking figured out, I will be tickled pink. I was really starting to get aggravated with it to the point of throwing the towel in all together. I started back on this car with basically the only goal of actually being able to enjoy driving it. And that vibration was a major road block on that front. So every step I take towards making drivability something that is enjoyable is a big win. Next up on my list of things to attack will be getting the front springs installed. The rear springs really jacked it up...so once the fronts are in I need to decide if I want to cut them any and then get a heavily needed alignment.

 

they look good really low, but being able to drive around without hitting the air dam or dragging the mid pipe everywhere goes a long way to enjoyment as I get old haha.

since the factory used the same rubber tranny mount for both style crossmember. I can only get they did it to raise the back of the tranny and/or tq arm up an inch or so? which seems like it would make pinion angle more steep?



I remember those rubber mounts, once the own one broke, the aftermarket ones would bearly last a day or so haha. with the factory tq arm on the tranny you almost had to go poly in a v6 haha.

 

Yep. I loved the look but absolutely hated the ride. Scrapped on everything, including my lakewood bellhousing which will really rattle your teeth when it hits at speed. I was looking when I had the front tires up on ramps the other night. It literally has like 1" of travel before hitting the bump stops. So you can only imagine the quality of ride it is giving...10 years ago when I was 21 I didn't care but now I can't stand it.

Thinking maybe this weekend I might get some time to install the front springs. Will see how things go.

 

Well after a solid 12hrs of work split between two days this weekend I got one spring installed...between fighting the tool and fighting the spring I was at my limit of being fed up. Took several breaks to calm down and reevaluate. I ended up cutting half a coil off to even be able to get them up into the pockets. The fronts are Moog 5660 so that should net about 1" drop from "new factory". Considering how high the new rears sit without being cut I figured it was a safe amount to go with. Hoping the other side goes a lot faster now that I have a method figured out.

My replacement torque arm mount shackles came in Saturday as well. During one of my breaks from the springs I looked into that. The previous owner of the torque arm definitely cut down the old shackles. And my transmission definitely hits if I use the new shackles. You can see in the photo below. I highlighted in red where I will need to cut some bosses off the tailhousing. I already cut the rear most tab off. Still need a bit more room so will need to cut the stub where the transmission mounted torque arm bolt goes. I guess if I ever regret doing this, I can replace the tailhousing. But I doubt I would ever go back to a transmission mounted torque arm.

 

Front springs are complete and torque arm has the correct shackles installed now. Took car for a short drive and it felt really good. My front end however is basically at the same height it was before. I didn't use any isolators on the spring tops, so maybe I need to get some to gain around an inch. With these springs though the front felt a lot better. Was plenty firm and felt smooth going down the oil and chip roads leading to the paved roads from my house. The old springs were so short they could be installed without a tool, so I think they were barely doing anything for ride. I will likely end up removing the 4th gen isolators in the rear. Right now I am sitting at 26" in front and 29" in rear...I like some rake but not quite 3" I'd really like to see around 27" front and 28" rear. Maybe even 27.5" rear.

WIth the torque arm work, shifting has improved greatly too with less jerking. Really starting to feel like a normal car finally. Still has a slight clunk in the torque arm when coasting or during load change. Thinking it is just bolt slop in the shackles. Overall though it is greatly improved.

I am coming along nicely with the tune as well. Have been making adjustments to proportional gains and acceleration enrichment. It really seems to have gained responsiveness with a touch of throttle from idle. Before it would rev kind of slow, now it seems to get up in rpms quicker. I took a lot of AE out of the tune because it was swinging way rich. Probably causing a slight bog. I will continue to make adjustments each drive. Technically now that it is late fall/winter, I am not "supposed" to drive the car with the antique plates I have on it. But I doubt I would get too much hassle over it around here.

 

if I remember right, years ago when I did springs. I had to pull the bolts at the back of the a arm, leaving the ball joints attached. that gave a lot more room for installation the spring than the ball joint. I didn't have a compresser tool.


I replaced the stock ones with the progressive eibachs which are shorter by a little bit, but I couldn't get the stock out with just popping the ball joint off.

​​​​I did reuse the isolator thou. so it only lowered it about about in inch or so from stock.

to late now, but if you go back in, it might make it easier.

 

Yep the old springs were Eibach Pros, but they were cut an unknown amount by the guy I bought them from...so no telling how much shorter they actually were. I had looked at doing that with the a-arms. I just didn't trust the tool and spring while maneuvering the a-arm like that. The tool I was using was the kind with fingers at the top and a fork down on the bottom. I was actually using the fork under the a-arm to then compress the spring down onto the a-arm. I had the strut top nut removed to be able to swing the a-arm, didn't even touch the ball joint. Safety wise it seemed solid and trust worthy but probably wasn't the "proper" way of going about it. I made sure to never actively work on the wheel well side of the spring in case it broke loose and became a projectile.

I have driven the car twice now and haven't scrapped yet on the air dam. So it was an improvement even if it is the same height. But I know plenty of areas where I would definitely scrap still.

After a warm fall we are officially moving into cold weather now. So I think my driving will be very limited moving forward as I don't have the heater hoses connected on this car. I also am going to be trailering my wifes old car (2016 Tucson) back here from my dads to get it in the garage. Now that I am basically caught up on my schedule for jetski work. But I need to pull the head on the Tucson hopefully just for some valve repair so we can get it sold off. That is my "must do" winter project in the garage. I've been contemplating pulling the dash out of the Trans Am to attempt repairing it before dishing out money on a replacement. Have been reading up on that.

 

Well I think I have made a pretty major decision...I will likely be either parting the car out or selling it as whole if I can get close to parts value out of it.

This is just one step in a larger game plan for purchasing a second gen CTS-V. I am basically selling off a lot of my toys to help fund that purchase. Wasn't a easy decision as I do really like the car but I am finally coming to terms with the reality that I simply do not have enough spare time to give this car the attention that it needs. Or even any of my other toys that need work for that matter. And even then, it just isn't exactly what I want right now. In reality if I was staying with a 2 door vehicle I would rather have a Corvette. But with us planning to start a family a sedan is the more practical third vehicle. I've got a very nice 2013 Harley Breakout that I hardly ride anymore, it just doesn't give me the same joy it used to after a close friend almost lost his life on his bike. And with starting a family that mindset will certainly only get worse. Then I also will be selling my old 85 K5 Jimmy that is even more of a project than the Trans Am and has been sitting with nothing done to it in basically 10 years.

I am trying to get an idea what the car is even worth at this stage. Selling off the tko transmission, headers/ypipe, FIRST intake setup, and 406 as a longblock with cam I think I could get about $5k and then maybe $1k out of the rolling chassis. The car has Koni Yellows and basically new tires, so those alone are worth a little bit on the rolling chassis. However I think I would really struggle to get near $6k out of the car as-is considering the paint situation....

 

it's a shame but I definitely understand it sucks for them to sit around. the guy I bought my c6 off years ago sold it for a crs-v wagon. they were having triplets.

but yeah, mechanical is fun, paint and body is brutal. I can't do it, it costs crazy money and is usually disappointing work when you get it back.

good luck with what you come up with.

my 2 cents in the corvette(at least my c6) is it's fast and fun in it's element. but gives up so much daily driver enjoyment from what my 02 4th Gen had. I never really drive the thing. it's been on quick jacks for over a month over small stuff I just don't have the motivation to do. I miss the more utility of the camaro. if it wasn't stolen, I'd still have it. had to try try a vette just to see how it was with the insurance money thou. and on a track day or mountain road. it's pretty amazing to drive, I just live far enough from those it's a every 2 year or more event to make it up there. and these days I trailer it because long interstate drives are brutal haha.

a ctsv would be overall great.

 

The solution for that (speaking as a previous C6 owner) is to get a C4. All the fun of a 3rd gen, in a Corvette package.

X2. Killer car. Best car we've owned so far, in our opinions.

 

the older c4 body style is growing on me. I used to like the newer rounded lt1 years, but the older ones look better to me these days. it would definitely be a fun project car to mess with. I'd want a pretty clean one to start with thou. but sbc and a tranny in the right spot seems a good thing.


I already have to many projects thou, my 3rd Gen is to clean and have had to long to part with it. it's a garage queen. I kinda wanna ppf the whole car before I get it back on the road haha.

my c6 seems to always have one to 2 small things they get in the way of me saying OK, it's done let me swap sides of the garage. right now it's an exhaust leak in the new headers slip joints causing idle fuel trims to go lean and run rough. got them apart to reseal. apart is as far as it got haha.

 

My dad has a 1990 Convertible C4. I actually am very familiar with them, he owned it my whole childhood. He had a 87 targa top with the 4+3 for a few years too. There's a small chance I will probably end up with it at some point. It has sat for 10+ years. It certainly needs some work though. Namely the new top installed.

 

Well it is officially listed for sale. Really would like to sell it whole before dealing with parting out.

https://www.thirdgen.org/forums/fire...-am-406-a.html

 

Still have the car. Been going back and forth lately on selling it. I still probably would for the right money but for now I will keep working on it and driving it. Didn't help that my buddy in my neighborhood bought a beautiful red 99 TA with 41k miles. Still selling the Harley and old Jimmy so might have some spare money to throw at this for body/paint.

Some to-dos I have waiting to be installed are a new front driveshaft yoke and front U-Joint. Still have a bit of a clunk and vibration going on I would like to eliminate. It is a lot better than it was before doing all the stuff last summer so I am making progress. Once I get those installed I will probably start looking at getting the AC system sealed back up and working. Already have a new accumulator waiting. Should hopefully cool really well with the brushless cooling fan setup.

I haven't even hooked up a laptop to it once this year for tuning. Really happy with the way it is running right now. I'm sure it could probably be dialed in even more with some time spent but being able to just get in it and drive has been pretty great. That is something I never had with this car before fixing all those engine issues.

 

How'd you manage that!?? I've been trying to stop doing that for a long time, but I can't... I just can't!!!!... lol

I thought I was getting close to that point, but now freaking Vanilla Ice (in that other thread) tells me I can learn how to change the code myself and it's easy. Damn you Vanilla!!

 

Ha! Sometimes you gotta let well enough be well enough!

Honestly it is because of my schedule. This time of year with the jetski repair side business I am lucky to come inside to eat dinner with the wife. I simply don't have the time to be going for joy rides and tuning. It drives infinitely better than it ever use to so I probably am overselling how it runs but it really is a get in and go tune now. If it had any weird quirks or big annoyances I would certainly be datalogging and trying to eliminate them.

 

I would love to see some one like him just setup a video and record how they go thur code like that.

 

good to see you're able to get some drive time in and. enjoy it.

 

Yeah the coding is definitely impressive. Way over my head but I kind of wish I could do modifications to the coding with the EBL setup. Or at least attempt it. I think I could force myself to learn it if it was something I could benefit from. No interest in learning it if I can't use it though for this.

 

Been a very busy summer with the jetski side business. Didn't really do anything with the car due to that. At this point I am convinced to go ahead and keep it unless a great offer comes up for it. The good news is with having a great season for the business, I have saved up a little chunk of change for spending on the car while also having enough to also keep the wife happy with some projects she wants done.

Now that season has slowed down for me some I have been tackling some projects I had for it. Got the new yoke and front u-joint installed. Replaced the remaining pieces of the front steering components I had purchased to go along with the new tie rods I did last year. Installed the steering shaft upgrade. Attempted to adjust the steering box but I think it is well worn past its adjustability. It took all of the adjustment to even begin to remove the play it had. But then the steering didn't want to return to center while moving. I will probably look into a new box for it. Steering is tight aside from the play in the box now at least.

This past week I've had a lot of the interior removed for some audio upgrades and wiring up the rear hatch release. It kind of snowballed on me with the audio...started out with just installing some 4" speakers up front. While I had the sub box out to do the rear hatch release I pulled the single 12" it had in it to look it over. Years of sitting in the sun did its toll and the inner cone was shot. The box was kind of junky anyways and needed a new top so I got talking to my buddy/neighbor with the '99 TA. I knew he likely had some equipment laying around cause just about every vehicle he owns has audio systems. I first asked about just a single 10". But he said he had these two 12" subs he'd give me for free along with two amps I could use and if I like them we will figure out a price down the line...so here we are! Don't worry I have carpet coming for the sub box!



It will be a hodge podge system for sure with all the mix match going on. Pioneer 4" speakers up front due to the very limited dash space Firebird/TAs have compared to Camaros. Some Kenwood 6x9s for the rears. 12" Kicker Comp RTs. And then the two Skar Audio amps. Certainly not a "powerful" system but should be a huge improvement from before.

My dash pad is pretty toast. I think I am going to leave it out for now and attempt a refurb job on it over the winter using some marine vinyl/faux leather to recover it. After that I want to do something about the door panels. If I don't go with some black GTA panels, I could probably incorporate that same material from the dash into the doors as well.

Then looking further down the line, I am going back and forth on paying someone to paint it. I spoke to a local hot rod paint guy at a car show very briefly about it. He ball parked a 10k figure on paint. Which honestly is about what I expected for a professional job. To get that done though is going to take me selling some toys off, otherwise the wife would never approve of that kind of spending.

 

Have been asking around on the paint side of things. Actually meeting with a guy later today with the car so he can take a look at it and throw me a number.

Had one shop throw me price that I think was a "we don't want to but will if you pay this" amount. Starting price of $25k-$30k for a "restoration" style paint job starting from the metal and full body. 2 year wait list and 2 years to finish it...any repairs and "extra" work is charged per hour and parts. I respectfully said no. I'm not looking for that kind of paint job on this car. I can certainly understand the work involved for that and for some cars that might be worth it, but this one definitely isn't one of them. Don't get me wrong I love this car, but it isn't that special to be spending that kind of money on it when there are other much cooler alternatives that kind of money could be spent on.

Will see how today goes with meeting this guy and will continue asking around more to be able to shop around comparing pricing. I'm still not 100% opposed to painting it myself, it's just finding the time that is the problem. Winters were usually my down time season, but each year I get more and more winter projects for customers lined up. The good news is I have heat in the garage now that I've installed a mini split.

 

always wish I knew how to paint cars. I'm sure it's tons of work, but man. I don't need perfection either just a good driver paint job. if it's to nice. door dings and paint chips just make you not want rod drive it.

hopefully you can find a nice middle ground.

 

This is precisely why I would never consider $25k - $30k for a paint job on this car.

https://www.thirdgen.org/forums/fire...t-gta-13k.html $24k for a beautiful 13k mile car with minimal flaws.

My car simply isn't the one to be spending that kind of money on. Like you said, I just want a good driver paint job.

 

Well this past winter I pulled the transmission with the plan to resolve an oil leak that was coming from what I thought was the rear main seal. After using some UV additive and running the engine with transmission and scatter shield removed I found it was actually leaking from the rear china wall. So I pulled the intake to reseal that and went ahead with going through the transmission. It received a "shift upgrade kit" from Liberty Transmission. Included carbon lined synchronizers for 2-4, bronze shift fork pads, and some shifter linkage upgrades. Also replaced the complete 1-2 syncho slide assembly. The teeth were fairly worn. As well as threw a rear tailshaft bushing in it.

Got it all back together and went for a few mile drive. Pulled it back into the garage and it has sat for about a week with no oil leaks showing underneath. Hopefully we've resolved that issue. Next Friday I have off and I think I will try to get it over to a alignment shop to install the new front tires I had ordered before winter and get it aligned with the new strut mounts. As usual plans can always change but my tentative plan at this point is to resolve any and all remaining driving issues this spring/summer and then take it somewhere for paint this coming winter. I have a feeling I will be abandoning the UMI torque arm for a different setup to fully resolve the clunking/vibrations I have been chasing for a while now. It did feel decent though on that first drive. Little to no clunking but vibration slowly came in above 75. It is definitely better than it started when I first went down this rabbit hole. I would also like to get the AC system back up and running before the real heat of summer hits.

 

nice to hear your out diving it.

I fired mine for the first time with the EBL p4 a week or so ago. idled and some good chop. I didn't get it out of the garage thou. it's kinda crazy loud with this 4in. I ordered a varex valved 4in muffler for it, hoping to get it installed and driving soon ish.


I tend to agree with the tq arm. unless you're going to do some drag stuff the stock arm if it fits is probably just fine and a nicer drive.

 

Awesome build thread! I am also running a 280XFI roller cam in my C4. I thought about the First intake for a long time but ended up going Miniram to chase higher RPM. I was taking a peak at one of your bins posted earlier and figured the difference in Idle KPA was the intake manifold, but then I realized the extra 56ci you have is probably the real difference lol.

 

might also check your map sensor. if it's not the old school oem gm. I just swapped back from a 3 bar for code 59 I was playing with years ago to a 1bar for ebl and somehow snapped the vac port off it. had 2 more non oem laying around, and some equipment at work that's now scrapped, we had 3 spare auto parts ones on the shelf new in box. I hooked up all of them open air and in the wud where it shows a/d counts only one matched what the old original 90s one said. so I picked thst one to run.

I have no idea of it matters at all. but might might not be apples to apples compared

 

Yeah the bigger cubes tend to swallow cams a little bit. I idle at about 800rpm and get about 45kPa. Worth checking what ??? mentioned regarding MAP sensor, mine is a AC Delco replacement.

I've noticed I am running fairly lean actually right now. And I believe I was having similar issues before this winter but my wideband was down in the fall so I can't verify that. Going to have to hook the laptop up to see what's going on and make adjustments as needed. Also still need to set static spark advance and lock the distributor down. It's gotta be close because it starts just like it always has.

 

I idle at 850 and around 57kpa and I think that is pretty reasonable all things considered. I'm not sure what brand of map sensor I am running but it came with the EBL Flash II ECU I bought several years back. It consistently reads 100kpa (or slightly higher/lower based on ambient baro) with the engine off and below 4000rpm or so it will show 98-99kpa at WOT, when will slowly drop to 95-96kpa at 6400rpm. I picked up 2-3kpa fixing the throttle cable and 1-2kpa more cutting out the air filter lid. I am happy enough with that, leaves a slight bit of vacuum to pull some crankcase vapor into my catch can. Stock bottom end is approaching 80k and it definitely breathes a little bit lol.

I feel like I am pretty close to the point of not needing constant laptop use myself, as soon as my BLM learns are showing 3s or less and I get some good track or dyno runs in I'll be happy putting the laptop to the side for a while. But like you were saying, sometimes things change and parts fail, no great way of seeing exactly what until you hook up a laptop. I stopped using my laptop for a while on the stock L98 setup, turns out my wideband failed. Of course I didn't actually need to use it until after the H/C/I swap and it sure made the first few fire ups interesting trying to figure out why I was stuck at single digit AFRs.

What do you run for base timing? I am still at 6 but I think going to 10 might help a bit with start up. Plus it doesn't like to run at only 6 degrees when the EST is disconnected.

 

I run 8 degrees for static. Will play with that once I disconnect the wire for setting it to make sure that is optimal.

I've never really pushed this motor much past 5000 rpm. I had started pushing it closer to 5500 the last few datalogs just to see how fueling was. Up to around 5200 I don't really see much of a drop in kPa so for a long tube runner intake on big cubes it breathes decently.

Friday I have a appointment to get the new tires mounted up front and a long needed alignment. I had always been waiting till I got adjustable strut mounts up front to do an actual alignment. After eating through the outer edge of the new tires I mounted in 2024 I figured it was time. I am going to throw my digital angle finder in the car with me to check torque arm adjustment while I have it on their rack.

 

Friday I drove the car about 40 mins over to an alignment shop to get the new front tires installed and alignment done. I had eyeballed the toe and camber when I installed the new tie rods as well as the founders strut mounts. My goal was -0.75 to -1 camber. The guy let me hangout back there with him while he did the alignment. I checked the driveshaft/pinion angle and made a small adjustment. Then once he got the machine setup we saw the toe was like this / \ by about 3 degrees. Spec is .1 so way off. Camber was just over -1 and caster was 3.3L 3.6R so we left the strut mounts alone and made the toe adjustments. Nice to have a straight steering wheel and a lot less scrubbing when turning in parking lots.

The driveshaft adjustment didn't seem to make any difference for better or worse. I am still not impressed with that UMI torque arm setup. It seems like immediately after install its nice and tight feeling with no clunks but then within a couple drives the clunk comes back. I've read about people getting different bolts for up front to eliminate any slop in the shackles but I'm not so sure it will eliminate it all.

I also need to pull my new WB sensor and do a free air. Because something isn't right about it. Reading peg lean nearly the whole drive unless hard in throttle even though it drives fine and is in closed loop.

 

Wideband is calibrated and reading a much more believable value. Making changes here and there to my tune. Concentrating mainly on AE. I reduced a lot of it to help with responsiveness and it feeling flat on initial accel. Think I am going in the right direction.

I am really getting the paint itch with this car. With driveability having improved substantially I am getting closer and closer to being ready to send it off for body/paint work. Here in the next month I am going to get moving on AC install I think and then see where I am at for funds for paint and also scheduling at the shops I talked to in the fall. I am selling a boat and sold my old K10 Jimmy back in the fall which those funds were going towards paint. Might be able to swing it ahead of my original plan to do it winter 2026/2027. Would be awesome to have it done in time to make a few car shows late summer.

 

what are you thinking for ac compressor? Just stick with the r4 or get with the sanden one?

I once years and years ago put a variable displacement v4 I think it was off a 4 cyl s10 on a 91z28 I had and it worked amazing and didn't cycle, so tuning with the old accell dfi 6 was much eaiser. but sadly it leaked and I didn't drive the car much back then, and then it parked and rotted away.

I have looked at my dead r4 compressor and wished I could put a v5 or whatever that was called down load on the passenger side where the smog pump used to be.

sadly this is the only Pic I have of that car that shows the short time I had it in there.

 

For AC I am going back and forth on several options.

Option 1: New Ac Delco/Genuine GM R4 from rockauto. Source R12 from marketplace. Factory Setup.
Option 2: Same new R4 as above but going with "Air Duster" R152A Freon. Supposed to be a closer match property wise to R12 than R134A.
Option 3: Sanden route with R134A. Slightly complicated with the tall valve covers to clear my girdles.
Option 4: Same new R4 as above but R134A.

All options would likely use the existing evap after flushing and maybe a new condenser. The condenser was new in 2016ish but don't know if any debris are in it. Might flush it and just see what comes out first.
I also might replace the big radiator I have in it. It doesn't fit right at all. With the brushless fan I should be more than fine with a better fitting 2 core.