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LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
New swing plates made. Intentionally went wider than the originals (also shown for comparison) for larger clamping surface against the bushing, and a better bolted joint. Just have to button things up and reset pinion angle.
I checked movement through normal axle travel and the torque arm doesn't have any perceptible fore-aft travel to the naked eye. That means the height of torque arm is a useless adjustment in my case, since the line of action will be the same regardless. It only has forward movement when the axle gets near full droop. The fact the torque arm stays so still might explain why I don't have the clanking noises that people usually hear with swing plate designs.
Glad I did this job because I found that 3 of 4 driveline nuts weren't very tight. Makes me feel better to find that and fix it!
Just bare headers. The Hawks 2" primary headers have better routings than the smaller headers. I don't struggle with the same plug & starter motor clearance issues as most people.
I have Hinson spark plug wire heat boots. Clutch hose is wrapped with DEI velcro heat shield. And the fuel and brake lines have maybe a 1-foot section wrapped in that same heat shield on the down-leg inside the tranny tunnel. The only place that headers get close to those lines is the down-leg where it's wrapped.
Would have been nice to have ceramic coating on the headers when new but I didn't want to spend the extra money back then. My friend ceramic coated his headers and it helped a whole lot. I won't wrap my stainless headers. I've heard it will exceed the skin temp limits of the metal and ruin the headers in a jiffy.
I think Improved Racing has an exhaust heat shield that stands off the surface so it doesn't trap moisture or get too hot.
Just bare headers. The Hawks 2" primary headers have better routings than the smaller headers. I don't struggle with the same plug & starter motor clearance issues as most people.
I have Hinson spark plug wire heat boots. Clutch hose is wrapped with DEI velcro heat shield. And the fuel and brake lines have maybe a 1-foot section wrapped in that same heat shield on the down-leg inside the tranny tunnel. The only place that headers get close to those lines is the down-leg where it's wrapped.
Would have been nice to have ceramic coating on the headers when new but I didn't want to spend the extra money back then. My friend ceramic coated his headers and it helped a whole lot. I won't wrap my stainless headers. I've heard it will exceed the skin temp limits of the metal and ruin the headers in a jiffy.
I think Improved Racing has an exhaust heat shield that stands off the surface so it doesn't trap moisture or get too hot.
I have my headers ceramic coated and MSD ceramic plug boots, the problem I had was with the oil cooler lines at the cooler adapter melted? for lack of a better description (Improved Racing adapter and -10 SS braided lines). I'm using the DEI shields on the fuel lines, so I'll probably use that on everything else (oil cooler lines, clutch line, ground cable, starter, etc.). I know the easy way out would be the wrap, but it's has too many draw backs and it's ugly. I saw your dyno video and was curious if you've experienced any heat problems with that beast of a motor? Thanks for replying, I appreciate your input.
I saw your dyno video and was curious if you've experienced any heat problems with that beast of a motor?
No problems here. I have a T56 and there is lots of space between it and the exhaust. Some of the 30 year old undercoating in the tranny tunnel is blistering though. Maybe it's heat, maybe it's just old and separating.
First drive and not impressed with these M&H tires in the slightest. Just made me want my Mickey's back. I'll give it another chance but this might be a very short lived relationship.
I think the M&H tires were just greasy being new. Working better now. Handling is a bit funky and had a few instances where they slide sideways in tight, slow speed corners. Giving me warning that these tires have really poor lateral grip. But then I discovered I forgot to install the front sway bar links so who knows. Increased tire pressure a few psi after that anyway.
Also increased compression quite a bit on the rear shocks and that feels like it has helped with traction in 1st gear.
I'm struggling again with controlling engine decent down to idle. Ideas are welcome.
Problem: Engine idles fine. Engine drives fine. Only issue is overshoot of idle speed when engine returns to idle. And it only happens in hot weather. The overshoot gets more aggressive as IAT gets hotter. More air flow fixes the problem (either opening the throttle blade or more % IAC position). It does not happen at all on cooler days with more air mass. The other problem is I can't depend on the Holley IAC strategy to catch the engine consistently and this is compounding the issue.
My interpretation of the symptoms is: (1) Engine wants more IAC opening when IAT goes up; and (2) I need to change my IAC Ramp Down strategy so that I can depend on it.
Proposed fix: This is what I'm thinking of doing,
1. Change my IAC settings to begin ramp down around 1500 rpm (instead of 2500 rpm). Hopefully that will make IAC Ramp Down function more consistent on a day by day basis by keeping it out of normal cruise range. But I don't think it will be able to catch the engine in free fall from a high rpm.
2. Make a custom 2D table of IAC offset based on RPM and IAT. This will be my airflow compensation for high IAT. And I'm hoping I can also use it to temper the engine descent down to 1500 rpm where Holley's IAC Ramp Down feature will take over and finish the controlled glide to idle.
2b. Another idea instead of #2 above is to reset my throttle blade base air flow as the weather gets hotter and hotter until I've got a minimum air flow sufficient for the hottest of days. (and then hope the engine doesn't hang in cold weather like it's done in the past)
This has been a nagging problem with both engines for 4 years now and I'm getting sick of it. I think I'm finally getting a handle on what's happening though. Thoughts?
This is mine right now not that it’s perfect but I do have a slight hanging idle on startups. Been pretty solid for two years now till this spring it’s been fighting me on a swinging idle on cold starts then at hot idle holds at 2000 rpm constant. So just put in a new IAC today and on first start and drive zero change then I figured I would reload the tune so got the laptop plugged and fired the car up and magically perfect idle again WTH.
I might have a good idea what's going on with your setup. Mine used to behave like that too and no amount of tuning was going to fix it. Just kept chasing the problem in circles until I figured out what it really was. PM me your phone number if you want to talk and compare notes.
I'm struggling again with controlling engine decent down to idle. Ideas are welcome.
Problem: Engine idles fine. Engine drives fine. Only issue is overshoot of idle speed when engine returns to idle. And it only happens in hot weather. The overshoot gets more aggressive as IAT gets hotter. More air flow fixes the problem (either opening the throttle blade or more % IAC position). It does not happen at all on cooler days with more air mass. The other problem is I can't depend on the Holley IAC strategy to catch the engine consistently and this is compounding the issue.
Wow! After 4 years I think I might have finally figured out this crap. Really controlled idle today.... like super duper controlled. Hope it stays this way and isn't just false hope.
Basically what I did was adapt the concept of an OEM style "Throttle Cracker" to Holley EFI. I made a custom 2D table of Idle Air Control offset as a function of engine RPM and Manifold Air Temp. Think of it as a dynamic IAC Hold Position. I think it's going to solve the problem of Holley's terrible IAC Ramp Down strategy. I mean seriously, if the Holley IAC Ramp Down just worked better then we wouldn't even be having this conversation in the first place.
I used datalogs to establish proper IAC values up to about 130F. Above that I don't know what it's going to need and hope I never have to find out.
With the Throttle Cracker table in place I was able to place the RPM to Enable IAC Ramp Down at a low level below normal driving. This keeps the IAC from ramping down at the wrong times, which has been a big problem for me.
Update: This throttle cracker did not work and began having serious issues within a couple days. I finally did get IAC Ramp Down settings below cruising speeds and have a rock solid transition to idle now. It was not easy! Engine seems to like lots of base air flow and very small amount of IAC (as in hovering at 0% when hot). Final settings are:
IAC Hold Position = 10%
Ramp Decay Time = 1.7 seconds
RPM Above Idle To Start Ramp = 450 RPM
RPM Above Idle To Re-enable Idle Control = 150 RPM
My car is becoming a b**** to drive as the weather gets hotter. Out of control bucking and idle problems. IAC also does weird things. I'm sick of this. Really, really, really sick of it.
My car is becoming a b**** to drive as the weather gets hotter. Out of control bucking and idle problems. IAC also does weird things. I'm sick of this. Really, really, really sick of it.
Yes, I'm feeling sorry for myself.
Has Holley offered any help at all? Time to switch to E38 ecm?
Has Holley offered any help at all? Time to switch to E38 ecm?
Got hold of a tuner that redmaroz suggested. Might try some remote tuning services. Still going to give it my best shot for the next couple weeks.
2nd gear synchros are roached too. Can't shift under heavy throttle. Going to limp it for the rest of the driving season but not putting the T56 back in after that. We'll see where this goes.
Has Holley offered any help at all? Time to switch to E38 ecm?
watching your struggle with the Holley is concerning and hope you are able to get the issues ironed out as you have put so much effort into it.
i am really on the fence on the holley. in general, with my RAMJET 350 project it runs well, but i have a couple of nagging issues which i am not ready yet to say are the tune or lack of it, but i know with the old 80's ECM (or EBL) i could easily have resolved it by now as the tables exist to easily deal with my issues in those ECMs.
The holley has so much going for it with its flexible architecture and there are a ton of things i like about it including all the accessories. i just added a pro-dash 6.8" that is basically a direct size fit for a DIN 1.5 radio and it is so great to be able to make gauge displays etc with all the engine info you can watch in real time. The flexibility on the inputs and outputs, and logic is great
With that said, the big issue is that there is so much left out or at a minimum not exposed for adjustment in regards to basic EFI control that goes back to the 80s. Their idle control parameters are a stark example of what is lacking compared to GM OEM.
The LS swaps i have done so far have all been with E38 / E67 and with basic LS3 to one with full TVS2300 supercharger the tuning to get great driveability has been relatively straightforward... part of this of course is that having both MAF and SD really gives you a lot of opportunity to dial it in and make progress that is stable operation while you get the VE table exactly right for example. Also Speartech makes a great harness ... also E38 is cheap, readily available, and extremely reliable
I had planned to standardize on Holley as there are things about the E38 i don't like... i would prefer to go cable driven, i would like to have output / input flexiblity, i don't like not being able to load a blank ECM (ie need a tech2 for the DBW portion), i don't like being dependant on tuning credits (ie hp tuners)...
i need to decide before this winter as i will be working on my 85 IROC with something LS new
Got hold of a tuner that redmaroz suggested. Might try some remote tuning services. Still going to give it my best shot for the next couple weeks.
2nd gear synchros are roached too. Can't shift under heavy throttle. Going to limp it for the rest of the driving season but not putting the T56 back in after that. We'll see where this goes.
Originally Posted by QwkTrip
I’ve been contemplating trying to adapt a DCT transmission to the car. Not easy yet, but it will get easy once the aftermarket cracks encryption of the transmission controllers.
But before I get too serious about such a drastic change, I figured I should get a little better understanding of how a car gets down the road. I've always heard things like horsepower wins races, shift at rpm as high as you can, 7 speeds are better than 4 speeds, steeper gears make a car faster, larger tires slow it down, blah blah blah.… But is it really true? I wanted to be able to visualize these things for myself so I made a spreadsheet with graphs to compare scenarios. It's basic, not real fancy, but I think the results are pretty interesting nonetheless.
Just wondering if you'd heard about the T56 Magnum-F? It's the same upgraded trans as in the 6th gens, but made to drop into 4th (and our 3rd) gens, since they hit a sweet spot of fitment for so many other swap platforms. That would definitely help with the syncros (in the 6th gen it shifts sooo nice), is much stronger and would drop right in. Or were you thinking of going a very different way?
Going back to the trans gearing discussion from a few months ago, I wish GM had spec'd the TR trans to have only 1 overdrive and make 1-5 steeper. Run milder rear gears (like in the BMW example you gave) and the aftermarket would be ready with steeper gears already, should people desire it. In my head it seemed like it would be a more efficient solution for mpgs and power delivery, but I'm hardly someone who they listen to.
I know Engineering Explained on youtube did a video of exactly this same topic that was pretty clearly laid out. He even pointed out that the newest Miata doesn't even have an overdrive, 6th gear is 1:1, guess they really wanted to take advantage of every bit of torque that they had.
watching your struggle with the Holley is concerning and hope you are able to get the issues ironed out as you have put so much effort into it.
Some of the strategies are primitive and it's those same functions where I'm struggling with the finer aspects of drivability. Although, most my personal frustration comes from my lack of experience and not knowing rule of thumb methods for fixing problems. It might take me 4 months to figure out something that an experienced person can fix in 10 minutes. It's really maddening and disheartening when you have no clue how to proceed.
It seems I might have made some progress today with the bucking. Still have other very weird things happening that I can't explain or figure out. NONE of this happened before I followed conventional theory for setting throttle body position. I'm tempted to just go back to my unconventional old ways, be less frustrated, and change throttle body base air flow seasonally.
Originally Posted by V6canvas
Just wondering if you'd heard about the T56 Magnum-F?
Yep, it's a TR6060 packaged to be a direct fit into a F-body. Rumor is it shifts better than a T56 with all the tricks. I'd probably do the Magnum F if I stay manual trans. But my car would be sooooo much faster with an auto. The timing of this sucks right now because I don't want to spend a lot of money. And I was kind of waiting to see if Tremec does an aftermarket DCT in the next few years.
I appreciate what you said. There's one thing I've learned over the years though: I'll take results over smarts any day. And I ain't gettin' results lately. I gotta get out of this rut somehow.
After 4 years of hearing loss from loud exhaust I decided it was time to experiment with lowering sound levels inside the car. Sound padding is some pretty expensive stuff, not to mention adds a lot of weight to the car, so I'm taking baby steps to see how little I can get away with. Guessing most of the exhaust noise comes from the back of the car so that's where I started.
I got some of the thick, multi-layer DynaPad (by Dynamat) and laid it in the back of the car under the carpet. Seams are tied together with extra-wide Gorilla duct tape. I kind of figured it might not do didely squat without covering the fenders and back wall, and that pretty much seems to be the case after first drive. I can tell it has potential though because now the exhaust noise seems to be more directional like it's mainly coming from the areas I didn't cover. Seems the next level is to cover the backside of the interior plastics. This probably isn't the right material for that job though, considering it's so heavy and doesn't glue down.
One downside is the extra padding makes everything in the interior fit super tight. I can barely latch the rear seat now, and the rear plastics are stuffed in really tight. Hoping it relaxes a bit over the next few weeks. And yes, it is hilarious watching a sweaty fat guy work in the back seat with the roll cage. But I've never scratched a thing yet and you might be amazed at some of my moves!
How heavy are we talking? I'm about to lay my dynamat (eastwood brand) but am worried about sound. I am certain my car will be an ear splitter. Are you running cats?
They say 1 pound per square foot for the DynaPad. Feels every bit of that.
My friend's H/C/I LS2 with 2.5" duals is downright tame. It has plenty of rumble but not loud. It's even comfortable with the cutouts open.
My 3" dual to 3.5" single is much louder. It sounds very healthy in normal driving and gets downright loud under WOT.
My friend's H/C/I LS1 with 3" duals and same mufflers as me is loud all the time.
So size does matter . My guess is 20 to 30 square feet in the rear area? 30lbs. Heavy but not terrible, especially over the rear wheels. I can offset that by losing 20 lbs. Uhg, still debating 3" duals vs 4" mufflex. That's the last major part my build needs.
Ya, I ended up using 2 sheets plus a small partial of a 3rd. The cargo hold is the problem zone because of all the curved surfaces that require cuts. I wasn't working with any glue so all cuts had to be in sensible locations so the panels don't want to fall down vertical surfaces. Basically every vertical portion needed to be anchored by a section that is laying on a level surface. I think I had 6 pieces total.
question: why didnt you want to glue or use the style with a built in adhesive backing?
I used a roll of Rammatt on the interior about 10 years ago and it had the adhesive backing. It was heavy, but it does a great job. I did not do the trunk well though
It's my personal preference for ease of maintenance. I like to be able to remove EVERYTHING down to floor pan if I have to do a super cleaning or dry things out. I've had everything from major mouse infestation to coolant leaks to water leaks. Had to clean & dry down to floor pan too many times already.
So I got under the car and looked where the exhaust goes. It is right next to the rear storage compartments on both side of the car. I'm guessing the side compartments could be picking up the vast majority of exhaust noise. Maybe I should have tackled those areas first before trying anything else.
I'm looking for something lightweight that I can stick to the backside of interior plastic panels. Found some peal & stick pyramid acoustic foam. Another possible idea is expanding foam "bricks" to build a sound wall in the tire well.
question: why didnt you want to glue or use the style with a built in adhesive backing?
I used a roll of Rammatt on the interior about 10 years ago and it had the adhesive backing. It was heavy, but it does a great job. I did not do the trunk well though
Dave, this is a different type of product. Regular Dynamat is not a sound barrier, it is a vibration dampener. It reduces the accoustics in the sheet metal and converts it to heat.
That's my understanding as well. While we see the adhesive backed butyl stuff glued into every nook and cranny of a car interior, it's not designed to be installed that way. As scooter says, it's a dampener. As such, only a portion of each panel needs to have an application.
The mass loaded vinyl, something similar (if not the same) as Qwik has applied is more about sound attenuation.
They're often used in combination to get the desired results.
Something I learned after I covered the entire floor of the Camaro.
Last edited by skinny z; 06-29-2020 at 08:23 PM.
Reason: 'cause grammar is important.
ahhh-ha! now I understand. Man, i learn something new on here all the time. thanks guys. I did the same as skinnyZ back a few years ago. glad I now know for the future. cool
Sounds like that product is Mass Loaded Vinyl. How much was it for what quantity? WHat is the thickness?
Yes, heavy vinyl sandwiched between different types of acoustic foam. 3/8" thick. $99 for 12 sqft on sale at Summit Racing (normally $129). The petro/gasoline odor is free.
I kind of figured it might not do didely squat without covering the fenders and back wall, and that pretty much seems to be the case after first drive.
Well it's done more than I thought. Went for a long drive tonight and it did take some of the bark out of the exhaust noise, especially at lower rpm's. My ears don't bother me as much as usual after the drive, so going in the right direction and feel better about money spent.
Meanwhile, idle quality still remains perfect without using any special tricks. Whatever I did I seemed to nail it. Been very difficult working out the buck around 1800 rpm though. It's going to be another night of pouring over datalogs and tacos. That's how stuff gets done, you know.... This car was built on Pepsi and junk food.
I’m in the same boat when it comes to the exhaust! After installing the 4 inch Mufflex I’ve been looking at sound deadening options. The shape of the rear hatch well definitely seems like it can amplify the sound quite a bit, especially with the muffler basically right below it.
QwkTrip have you resolved your STB issues? I used a MAC STB on my 91 Firebird for years without any interference with hood, original flat hood then a TA hood. My car was just a base model 305 TBI Firebird, I then switched to a 350 TPI motor and the STB still fit. I only took it off recently because I switched to a HSR. It doesn't triangulate to the cowl, but I suppose it's better than nothing. https://shop.macperformance.com/MAC-...ace-ST8292.htm https://www.thirdgen.org/forums/v6/3...rut-tower.html
I’m in the same boat when it comes to the exhaust! After installing the 4 inch Mufflex I’ve been looking at sound deadening options. The shape of the rear hatch well definitely seems like it can amplify the sound quite a bit, especially with the muffler basically right below it.
Have you looked at lizard skin, you could spray it on the underside of the car. Your gas pump door you have could also use a square of dynomat as just flat steel it will resonate. (also caught your last video on the pump, you really should paint that access door )
I have a combination of things from mylar bubble wrap, dynomat, and even some fiberglass insulation matting inside the rear trim panels in addition the jute padding etc-- its not modern day quite but it made the car seem much more solid. I also used foam tape in some of the dash board joints and other locations to get rid of rattles.
The spare tire well also seems to be a source of noise, I put some dynomat down in the bottom of those areas, just don't block off the drain hole.
Having the rear glass tented also seems to have an effect.
The biggest improvement came from new door seals though its amazing how much noise that cut out.
QwkTrip have you resolved your STB issues? I used a MAC STB on my 91 Firebird for years without any interference with hood, original flat hood then a TA hood.
Nope, never got one installed. Thanks for the lead, I've never heard of that one.
I had pretty much consigned to just making one some day. I still have the Kenny Brown piece laying around as a starting point.
This lousy COVID situation has stomped all over my summer vacation plans, so I decided to make the best of things by installing some new parts on the car. And the nice thing is I already had these parts! About two years ago I bought a Turn One steering box, and a DSE steering brace & sway bar kit. I dug the parts out of storage and tore into the car.
Out with the old... stock Delphi 800 series steering box, Global West "wonder bar", and Suspension Techniques sway bar. That sway bar was the first mod I ever did to the car back in 1994! That's from a time when things were ordered from the JC Whitney catalog and the internet did not exist.
In with the new.... Detroit Speed steering brace & sway bar, and Turn One steering box. The steering box is the Turn One "3rd gen" Delphi 600 series with 12:1 ratio. It's a direct fit with no modifications. New o-rings for power steering lines are GM part number 26001594. Steering definitely has a heavier feel than stock. I haven't been out on the highway yet to really feel out the tighter steering ratio.
The DSE steering brace.... not so lucky with the fit. I had to undo all the k-member bolts and spread the frame horns to slip the brace in place (or more like pound it in place). It wasn't a dramatic amount, and the frame stayed in that location after pulling out the bottle jack. I also had to grind a lot of material off the brace to clearance for the steering pump. One of the gussets is entirely gone now. Other than that, it was just the usual cussing and bloody knuckles, and a clump of grease fell in my eye. So pretty much normal.
Steering box put in place. This job isn't for weenies because the pitman arm securing nut gets tightened to 180 lb-ft torque. It helps to be *cough* heavy *cough* so you don't slide around on the floor when tightening. It was pretty easy for me. Don't try to tighten the nut against the steering column lock. Just let the box turn to the internal stop and then torque the nut. (Nevermind the gap between mounting foot and subframe, I hadn't torqued the bolts yet.)
Lastly, I filled the system with Royal Purple synthetic power steering fluid and purged the system by turning the steering wheel from lock to lock many times (tires off ground, engine not running).
Driver side has plenty of adjustment available, but passenger side tire is big time toe out for some weird reason. I stared at it for a while scratching my head and concluded it just is what it is and I better fire up the bandsaw and start cutting. Cut 1/2" off the passenger side inner tie rod, and 3/8" off the outer tie rod (including the chamfered nose). We'll see how far that goes. Going in baby steps to keep deep thread engagement inside the adjuster.
I was actually kind of surprised how easy it was to cut and file on the metal. It's fairly soft and easy to work with.
Driver side has plenty of adjustment available, but passenger side tire is big time toe out for some weird reason. I stared at it for a while scratching my head and concluded it just is what it is and I better fire up the bandsaw and start cutting. Cut 1/2" off the passenger side inner tie rod, and 3/8" off the outer tie rod (including the chamfered nose). We'll see how far that goes. Going in baby steps to keep deep thread engagement inside the adjuster.
I was actually kind of surprised how easy it was to cut and file on the metal. It's fairly soft and easy to work with.
Interesting? Gonna have to keep this in mind when get my Proforged parts and compare the tie rod lengths before installing. I plan on putting together a bump steer kit for the outer tie rod and using the Proforged inner tie rods. Did you keep your inner and outer tie rods together When you disassembled your front end?
Oh, great.... now my steering wheel is about 45° off and I've run out of tie rod adjustment. Suck a duck!!!
if you use the DSE intermediate steering shaft you also have the option of moving tooth to tooth on the steering wheel position vs the steering box as there isn't a set flat point as with the stock shaft. it also is much firmer than the stock rag joint and cleans up some space between the exhaust on the driver side
IDid you keep your inner and outer tie rods together When you disassembled your front end?
Yep, same hardware as before (Hotchkis steering links). It appears as though the passenger side was nearly out of travel anyway so this "fix" was probably overdue. Steering wheel is straight again and I get an alignment Monday.
Originally Posted by alan91z28
if you use the DSE intermediate steering shaft you also have the option of moving tooth to tooth on the steering wheel position vs the steering box as there isn't a set flat point as with the stock shaft. it also is much firmer than the stock rag joint and cleans up some space between the exhaust on the driver side
I'll definitely keep that in mind for the next go-around. Right now I'm sitting pretty good with a hybrid Astro / 4th gen F-body shaft that is still functioning well.
04-28-2020, 10:57 PM
There's one thing I've learned over the years though: I'll take results over smarts any day. And I ain't gettin' results lately. I gotta get out of this rut somehow. 
. My guess is 20 to 30 square feet in the rear area? 30lbs. Heavy but not terrible, especially over the rear wheels. I can offset that by losing 20 lbs. Uhg, still debating 3" duals vs 4" mufflex. That's the last major part my build needs. 
Don't try to tighten the nut against the steering column lock. Just let the box turn to the internal stop and then torque the nut. (Nevermind the gap between mounting foot and subframe, I hadn't torqued the bolts yet.)
