SirReveller

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GTA matt

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T56 magnum came in from American Powertrain. They were very easy to deal with, and provided me with the proper shifter for a thirdgen, as well as an adapter plate so I can use my T5 bellhousing and hydraulics and all the other parts and hardware to complete the swap. I decided to get a Lakewood bell, as the stock one isn't exactly confidence inspiring. The T5 is out, and I checked the alignment of the bell so I could get the appropriate offset dowels coming (.007" in this case). First problem: nobody makes a bolt in transmission crossmember for a magnum. Its longer then a regular t56, with a different tailshaft. I spoke at length with Spohn Performance about a solution, as I've had their torque arm and 700r4/t5 crossmember for 15 years, and at least wanted to re-use the torque arm to save a couple bucks. Although they were very helpful, I was told that their arm wouldn't work on a magnum and I was pretty much on my own. My solution was to buy their LSX/t56 swap crossmember and cut it to fit my needs. I'll be cutting out the center of the crossmember and moving it back 1 11/16". I'll also shorten the torque arm the same length. The driveshaft length also shrinks by about 5 inches, along with a 31 spline yoke.

scooter

iTrader: (11)

I just looked up the dimensions on the Magnum. The input shaft is a little shorter than the LS T56, so the bellhousing is shorter, and the length to the trans mount is only ~29/32 longer than the LS T56. You may be able to get away with using the LS T56 crossmember

ShiftyCapone

iTrader: (7)

Correct. I have tried multiple cross members and each bolted up to the magnum i'm using.

GTA matt

iTrader: (1)

All the published dimensions I found on the magnum are incorrect. Or at least they don't match up the the one sitting in my garage. The dimensions I found show the trans mount bolts at 26.6 inches back, mine without the adapter is at 27.5, or 28 with the adapter. The overall length is nearly 2 inches longer then shown, and the shifter location measurements are wrong too.



The measurements I have written are the transmission body WITH the 1/2" spacer, without the bellhousing. My bell is 6.46"

GTA matt

iTrader: (1)

My offset dowels have not made it in yet, so I was unable to get the final install done on the transmission. I modified the trans crossmember and shortened the torque arm. I probably could have gone a couple different routes with either, but I don't mind doing fab work, and got to save a couple bucks on buying a different torque arm setup. I moved the center of the trans crossmember back, welded it back together, then welded 1/8" plates to reinforce it top and bottom. The inside diameter of the torque arm tubing is 1", so I got some 1" x .250 wall tubing, sectioned the torque arm, put the 1" pipe inside, and welded back together.









I was setting the length on the adjustable clutch fork pivot in my new bell and noticed something on my original bell. JB weld.... The bell was cracked and someone used jb weld and rtv or some sort of epoxy on it. Now I'm really glad I got the lakewood piece. I really wish I knew the story behind that... or maybe I don't

GTA matt

iTrader: (1)

The flu had me knocked out for a week, but I'm finally back making some progress. Transmission install is complete. The magnum fits perfectly in the tunnel, no hammering or major cutting required. I did have to trim a 1/4" around the rear of the shifter opening to allow clearance for the shifter base. My t5 had a pro 5.0 shifter and shifter handle. I ended up cutting 2 inches out of the handle and tig welded it back together. The bolt spacing is the same, but I did have to enlarge the holes a few drill bit sizes. Shifter location is absolutely perfect in the car.

I am still waiting on my lifters, but decided to go ahead and run it with my old ones for the time being. I adjusted the valves, installed the stud girdles and fired the car up for the first time in over a month. Ran it through the gears, checked the clutch engagement point, everything seems great. I installed some DEI plug wire covers for a little extra insurance, also bought a derale dual fan and shroud setup. The car hasn't ever ran hot, but the last time I drove it on a warm day, I felt like I couldn't control the temperature the way I wanted to. I know full well it won't work out well on a 100 degree day in traffic with the ac on. If the fans don't work as well as I need, I'll upgrade the radiator. I've also now got a set of competition engineering subframe connectors sitting in the garage. I mentioned earlier about wanting to have the exhaust done before purchasing a set. These should fit with minimum modification on the passenger side around the exhaust. I have the same set on my GTA and really like them since they give an excellent location for jacks and jack stands.

Seriously the only picture I have of the trans install...



pro 5.0 shifter sectioned 2"

1986BANDIT

the amazing aftermarket aerodynamic "garage door weather stripping" it definitely takes the hit for the nose scrapes

GTA matt

iTrader: (1)

I took the iroc on the 3 hour drive down to Charlotte this weekend for the autofair. Car ran absolutely flawless, saw a lot of nice cars, met some great people and even remembered to take a few pictures

Ty92Z

iTrader: (11)

Saw you and your car there. Came by a couple times, but you were engaged in deep conversation so I didn’t disturb you. Car looks great in person.

GTA matt

iTrader: (1)

I really cant believe the amount of attention my car and Chris's (Nuff nuff) cars got. Anytime I was near the car I wound up talking to someone for quite a while. Sorry I didn't get a chance to chat with you.

GTA matt

iTrader: (1)

Finally got a chance to install the subframe connectors I've been sitting on for a few weeks. Driver side was of course straightforward, and passenger side just took a little notching to get it to clear the exhaust. I still had some material leftover from modifying the trans crossmember and used that to fill in my cuts. Really not sure what's 'next' for the car, it's never done, but at least all the big, major items are complete.

DynoDave43

iTrader: (11)

Nice! Have you driven it since installing them.

GTA matt

iTrader: (1)

I've put a couple tanks of gas through it since putting them on. There's definitely fewer squeaks then before and the car feels more solid.

GTA matt

iTrader: (1)

So a funny thing happened. The tinted tail lights have been bugging me since day one. Not only did I not like how they looked, I'm not a fan of any type of tail light covering, for legal and safety reasons. I finally got around to addressing it, Thinking the lights were painted, I was ready with some acetone, sand paper and buffers......only to find out that they were simply tinted with regular window tint. So literally 2 minutes of my time to peel it and clean the residue The guy did a heck of a job putting the stuff on, I'll give him that. I also took some time, since I was in the buffing mood, to polish up the intake manifold.

STREETDEMON

Just made my way through the thread. Nice ride!

GTA matt

iTrader: (1)

Took a ride with some friends from our local Camaro club on memorial day for some 'scenic' pictures around the area.











I've been dealing with a resonating vibration in the car from the very beginning of this build, around 75 mph. I pretty much had it traced down to the gear set. I went ahead and installed the 3.25 gears I purchased before I did the t56 swap, just to see if it would fix it, and it has. The gears are a little on the tall side, but not terrible. The 3.70 gears were a new set of richmonds, they physically look fine, were set up perfect and were quiet, just had this crazy vibration. I'm a little gun shy about buying another set, in case it was just something with the harmonics of the driveline that didn't agree with that ratio. I have a set of 4.10's on hand as well that I may swap in, but we'll see how these do for now.

GTA matt

iTrader: (1)

I made an appearance in this video at the 6:20 mark, and did a brief interview at the 14:35 mark for anybody interested

DynoDave43

iTrader: (11)

Looks like a fun outing.

The car sounds nasty!

Roblaza

iTrader: (1)

I am in love with this car. Awesome work man!

GTA matt

iTrader: (1)

Took the car autocrossing this weekend, not only my first time on an auto cross course, but really my first time pushing this car hard. It performed flawlessly. A bit of understeer that could be easily corrected with the throttle. I erred a bit on the side of caution, as the course was very slick, with trees and concrete curbs all around. Absolutely the most fun I have had on four wheels.



Turn your volume up!

https://www.youtube.com/watch?v=M4iI...ature=youtu.be


Took a nice picture of the car last weekend at the airborne museum in Fayetteville

DynoDave43

iTrader: (11)

Autocrosses are a load of fun! Definitely something I want to do with my T/A.

GTA matt

iTrader: (1)

I'd like to give a huge shoutout to Detroit Speed. I ordered front and rear sway bars from them on friday 7/19 at 12:45pm, standard shipping. The following day, the fedex man is delivering them at 11 in the morning. Very surprised. The quality of their parts is phenomenal! I went with their upgraded wonder bar/front sway bar combo, and rear sway bar for my 3" axle tubes. Front bar was pretty straightforward, as expected. I knew for the rear bar I would run into difficulty due to the existing arb and the backbrace on the housing. I was willing to remove the arb if needed, since its certainly not a must have on this car, even if I do go drag racing, however, the bar won't fit regardless, due to the bracket for the torque arm. I'm going to make up some brackets to weld to the existing uprights for the arb and I *should* be able to keep it on the rear and have the sway bar hooked up to the stock pickup points. I'll update that as I go. I'm running another autocross in august.

ShiftyCapone

iTrader: (7)

I too have this kit and indeed it is really well made. Do you have a picture of your lower radiator hose and how it fits by the DSE passenger side wonder bar mount? I have an aftermarket radiator but the lower hose location is the same as stock and there is zero room for any type of AN and or fitting to put a hose on. I no longer have my stock radiator to compare too but I can see this being a problem for anyone running this DSE piece.

GTA matt

iTrader: (1)

The lower hose is actually pressed up against the idler arm mount portion of the wonder bar. It could be cut/notched/welded for additional clearance for an AN line setup, but would take a bit of work.

ShiftyCapone

iTrader: (7)

Yea, I have gone through about 50 different AN fittings and none of them clear. I might have to modify the DSE brace like you mentioned. That could have made the idler arm side smaller than it is. Not sure why they made it so large.

GTA matt

iTrader: (1)

Some more updates as I continue to enjoy this car. It would have taken a good bit of modification to get the DSE rear sway bar to work with my rear end setup. Its not something that can't be done, but once I start cutting and welding, things can't be undone. I decided to hook up the ARB and see how it responded on the autocross course. Previously the car had some moderate understeer, but was controllable, and I could use the throttle to induce oversteer on corner exit. I wanted to car to have an improved turn in, with a more neutral feel. Along with the bigger front sway bar, I put 1 degree of negative camber in the front (the most I could get out of my stock camber plates) and added a little more rear brake bias with my proportioning valve. Corner turn in was amazing, very responsive. However, from mid corner and off, it had an extreme amount of oversteer, the rear end really felt disconnected from the road. I have another event next weekend, I've unhooked the ARB, and I'll see how it reacts before I make drastic changes with mounting the rear bar.

I scaled the car again, haven't weighed it since the t56 swap and the subframe connectors. It's gained 168 lbs The connectors weighed about 40 lbs, the t56 magnum is a tank, and the sfi bellhousing was very heavy as well.

without driver, 3/4 tank of fuel





I've also been entertaining the idea of running e85 and have been fine tuning timing and fuel. Unfortunately, I found out I am out of injector on pump gas. When I was putting this thing together, I never anticipated it would make the power it does, so I only bought 36 pound injectors. I bumped fuel pressure from 52 to 62 psi which dropped pulse width by about a half millisecond, but its still showing 100% duty cycle, so new injectors will be coming soon. Also looking at the logs, my throttle body is a restriction, by 6-7 kpa, which is about 2 inches of vacuum. Removing the air intake from the throttle body only netted a .5 kpa improvement, so a 58mm throttle body is on the horizon as well.

UltRoadWarrior9

I've read on many threads here about running out of fuel supply for larger small blocks. I've got 42lb/hr injectors on my build but I'm worried when I finally get to the stage you're at, the OE fuel pump won't be able to keep up. Will you be able to tell if it's the injectors OR lack of pump volume and/or too small diameter fuel lines?

tom3

Whoa. For a "not a project" build that was sure a lot of, well, everything. And really nice to see a third gen get that amount of love. Thanks for posting all this, interesting!

ShiftyCapone

iTrader: (7)

No OEM fuel pump should ever be used for an ls swap. A swap that needs 400+hp of fuel supply needs a hotwire kit and sturdy aftermarket pump. Stock 3/8 lines can support enough power. Its rarely a restriction unless you are making 4 digit power.

QwkTrip

iTrader: (22)

That is a huge pressure drop! You're going to feel the improvement when that is fixed!

Fuel injectors will go to a high duty cycle whether the injector is too small or the pump is too small.

If the fuel pump is too small then you'll see fuel pressure drop, and the engine will go lean. If your engine controller has closed-loop compensation at full throttle, then the fuel demand will spike high trying to make up for the lack of fuel pressure.

GTA matt

iTrader: (1)

Yeah, your stock pump won't do. I've made 400hp or so on my stock pump, but that's about the limit. I'm comfortable with my current 255 pump up to around 600 on gas, it wouldn't work on e85. The stock lines aren't a problem on probably about any NA small block. As far as telling if running out of fuel is pump or injector related, you can monitor rail pressure and AFR during a pull and go from there.

GTA matt

iTrader: (1)

Yeah, this thing kinda snowballed....


I knew it would be a little undersized, but seeing the numbers confirms it. The motor is making some pretty good steam. I'm looking forward to seeing how it responds to a bigger throttle body.

GTA matt

iTrader: (1)

Went to an autocross yesterday at NCCAR, sadly, I have no pictures or video. The course was very fast and the car performed extremely well. Unhooking the rear bar got rid of the terrible oversteer I had at the last event, and the stiffer front sway bar and camber settings helped with turn in, car was very neutral overall. I was 10 seconds faster then the next closest novice cam car, and my high speed was actually 7 mph faster then the overall winner (67mph vs. 74 mph). I should have raised my limiter, probably would have gained a little more speed, as I was banging on the limiter a good 4 or 5 times before braking. The car could definitely benefit from good shocks and stiffer springs, but after the rear sway bar fiasco, I'm going to be very careful about changes that upset the cars balance.

GTA matt

iTrader: (1)

I lied, there IS a video of one of my runs. Quality kinda sucks, but it sounds amazing lol

https://www.youtube.com/watch?v=IioT...ELuFZgX1-rzeno

GTA matt

iTrader: (1)

Hard to believe it's been a year since I started this thread. Time has flown by! 58mm throttle body from TPIS is installed, but honestly, other then being bigger and having a nice appearance, I really don't have anything nice to say about it. For your $490, you won't get any bolts to attach it to your intake. The stock bolts are nearly a half inch too long, and the bolts that came with my old BBK were also too long. I stacked washers under the BBK bolts for the time being... It came with screws for the TPS, but they were too short, and the threads are different then the factory screws. I had to rig that up to work. The linkage for the throttle cable is positioned pretty far off to the side, putting the cable at a crazy angle that could potentially cause the cable to come off. There is a visible gap between the blades and the bore, with the blades closed all the way. Not surprising, the lowest I can get it to idle is 1030 rpm with the iac at 0. I've had the idle set to 975, with the iac counts between 5 and 10 with the BBK. I feel sorry for the poor fella that buys one of these with a milder engine. Probably wind up idling at 1300. That said, it IS inhaling a lot more air. I left the tune alone and did some pulls. You can see in my logs a few posts up, I had the wot fueling pretty well nailed down, afr stayed in the mid 12's, with the computer only needing to add a few percentage points to the fuel trim. With the new TB, I saw as high as 14.2 afr, with the computer adding over 20%. I know my injectors are maxed, so a bigger set is next, probably 60's so I can run e85, and then I'll begin tuning the fuel tables again. KPA is still dropping more then I would like, but I'm going to do some more testing, I suspect the intake ducting may be a restriction? I'll also be calling TPIS about this throttle body.

GTA matt

iTrader: (1)

I haven't really updated this in a while, so this will be a culmination of the past few months, a big slowdown from this time last year! It's nice to just be able to get out and drive, has about 8000 miles on it now. I drilled the back of the intake for the MAP sensor, puts it out of the way and eliminates the vacuum hose I had ran to it. Installed the Johnson lifters I had been sitting on for a while. I had zero issues with the GM lifters, just feel better about the long term reliability of the Johnsons with the spring pressure I'm running. I installed Racetronix 62lb injectors, which required a little tuning with throttle tip in. I'm going to get the tune nailed down on gas, then try e85 and see how it does. Plans for this spring are to add weight jacking springs all the way around. It could really benefit from stiffer springs on the autocross course. I also plan on adding a few bars and braces to the subframe connectors. It still seems to have a bit of chassis flex.









I think I'm going to have to ignore fitech's duty cycle calculation. Pulse width has been cut in half, however it still says 100%, go figure. Actual DC is about 50% on gas. I was dangerously close to being out of injector before, with actual DC around 90-95%.

UltRoadWarrior9

Nice to see your progress!

I'm curious, as I noticed you have T-Tops like my 86 IROC and a XFI292 cam and subframe connectors. Do your T-Tops leak? Just curious.

Sorry for such a stupid question

GTA matt

iTrader: (1)

They do not. It has all new seals. When I got it, there was a pretty large gap between the passenger window and the t-top where it did leak. Quick adjustment of the window tightened that up.

GTA matt

iTrader: (1)

Some more updates on this thing, waiting on a LOT of parts. After running a few autocross events, seeing how the car drives and what areas need improvement, I've decided to pretty much redo everything steering and suspension related. On the list: Lares 1282 steering box and all parts of the steering linkage, Ground Control weight jack springs and Ground Controls custom valved Koni struts and shocks. I'll need more rubber on the ground, which means wider wheels. After a lot of careful measurements, I've ordered a set of 18x11 Rotiform 917 wheels. I love the look of the iroc wheels, and while I wasn't looking for an exact match, I feel like these are pretty close, while still keeping a clean look. Went with full polished, 2 piece wheel. Also waiting on a Dewitts radiator to help keep temps under control as we move into the summer. Hopefully the virus doesn't slow down the build times on all these parts so I can have the car ready to go when life returns to normal.

88coupedoop

I took latin in high school and college and still didn't understand a word you just said.

Advertising my ignorance and looking forward to being the Newb in the community asking Newb questions. Really enjoying following these threads though.

DynoDave43

iTrader: (11)

Just keep reading...you'll get there.

GTA matt

iTrader: (1)

While waiting on parts to be delivered, I decided to build a less restrictive air intake. I had mentioned previously about vacuum still being present in the manifold at wide open throttle, caused by the restrictive tpi air induction setup. I know there's guys who have modified the stock air box, but I am much better with metal then I am with fiberglass and plastic. I had some 4" stainless pipe from another project and fabbed up a system to pull air from under the battery tray. I will be relocating the battery, either to the rear of the car or over to the drivers side, cutting out the passenger side battery tray and locating the filter there. I'm holding off on 100% completing the system now, as the overflow hose on the stock radiator is in the way. With the new radiator being aluminum, I'll just relocate the fitting out of the way on it. This was my first time tig welding thin stainless, and making pie cuts. Turned out pretty well. I'll polish up the tubing when its complete.

GTA matt

iTrader: (1)

Polished the intake, which turned out amazingly well. Worked out a location under the battery tray where the filter will be located, behind the marker lens so it will be away from any debris coming off the front tire. I'll fab up a deflector to help funnel some air to the filter.





This will be welded on the end of the intake tube after I cut out the bottom of the battery tray. At this point, I'm just using scrap material to make the bends. Holding off on cutting out the tray until I officially relocate the battery.



Filter will go on the end, I'll remove the plastic shield and put a deflector in its place.



New setup really dwarfs the old 3" tube!

drknow90rs_ss@y

iTrader: (3)

Wow! Loving your car! Can you detail the mods made to the hood? I'm really digging the replacement of the faux hood louvers with something that actually might be functional for removing hot air under the hood. The louvers on my '86 IROC-Z are pretty trashed and broken anyways (And I don't like things that really serve no purpose.), So it would be a perfect mod for me 😁. Are those made by a company, or were they custom made? Either way, I would love to see some close-up pics, if you don't mind.
Your car sounds, looks and performs awesome!
DR.K.

GTA matt

iTrader: (1)

The louvers are made by a company called trackspec. I think there may be someone else making a similar set as well. They were installed by the previous owner, but installation looks pretty straightforward. I don't have any close up pics of them.

drknow90rs_ss@y

iTrader: (3)

Great! I will look them up.
Thank you!
DR.K.

GTA matt

iTrader: (1)

So things are escalating pretty quickly once again. What started out as a simple cold air intake and 'track' muffler delete has turned into much, much more. The intake idea has been scrapped. More on that later. I wanted to make a muffler delete pipe for when things finally do open up again, I can take this thing to the track and have as free flowing exhaust as possible. I had my suspicions that the spintech muffler was a little restrictive, and based on how lean the car ran afterwards, I was correct. However, removing the muffler can be a bear, with the clamps and tight fitting pipes. I wanted something I could quickly swap between, so I welded V bands on the over axle pipe, spintech muffler, and made a muffler delete using 4" stainless and a vibrant 4" muffler. Some tracks require mufflers, and although the vibrant is a loose interpretation of one, it's technically still a muffler. It's freakin loud. Sounds awesome, just obnoxious loud. A keen observer may notice I used the intake pipe I built for the exhaust. It actually worked out perfect...

The intake idea was scrapped in favor of a pair of twin turbos (peer pressure is a bad thing). I may have mentioned back at the beginning of the build that I eventually intended to run a procharger on this thing, which is why I built it with forged internals. I fully intended on putting a D1 on it and making around 7-800 hp on the current setup. Which is pushing the limits of the block pretty far. However, a friend talked me into going turbo. My requirements were that I keep AC, exhaust out the back and the stock hood. A big single would require a 4" downpipe. Most guys run this where the ac box goes, so that idea was out. I decided it would be easier to package 2 smaller turbos with 3 inch down pipes. I actually have a really nice stainless header kit I bought for another project in the garage and figured I'd utilize for this. While googling images to gather some ideas, I ran across the cx racing twin turbo kit. I know its just ebay stuff, but I probably couldn't build something as good myself, so I'm giving it a shot. I'm making some modifications to it so I can keep ac. The entire serpentine system is being swapped out in favor of an Eddie motorsports serpentine system that is much more compact. Turbos are vs racing billet wheel 61/62's. On low boost it should easily make my 700hp goal. If everything works out as planned, I'll start building a shortblock that can handle 1000+ sometime in the future. We'll get a handle on this stage first before I get too deep... Throughout all this, I'm still waiting on the steering/suspension, radiator and wheels from my previous post. Hoping to have a 2-3 week turnaround time on everything.

I finally got rid of the mufflex exhaust tips I absolutely hated from day 1...





Muffler comes off in under a minute now







I've already installed a methanol injection kit (snow performance), since I'll really be pushing it with my compression. It's like this area of the car was designed for the pump and reservoir

UltRoadWarrior9

TIG welding.... Nice!

So it seems you've built this car for autocross but now with the twin turbos? Will it now be a straight ahead machine?

Loving your posts man, thanks for updating your IROC's history.

GTA matt

iTrader: (1)

Still planning on doing autocross. Its way overkill for that, but hoping it stays as well mannered as it is now. Just itching for more power.