Trying to get my 89 iroc twin turbo running right and strugling with it.
The Basics
Twin t3/4 turbos new
Big FMIC
HKS bov
Tial 38 wastegates
3" dp
stock 350L98 with a stealth ram intake
72# inj.
FAST WB ecu
Big fuel sytem etc etc etc
6 speed

Car worked great in the spring was very fast but blew up the stock shortblock with 15# boost because the actuators didn't work properly. So I get the Tial 38 external wastegates. I get a new 02 from FAST since the old one was ruined from the antifreeze. So the problem starts when I put the new stock engine in it this winter and when I fire it up after a couple times in and out of the shop maybe 20 minutes of run time timing it etc a piece of the header weld inside comes loose and the impeller stops spinning and car sounds like it has a horible exhaust leak. I think wtf. I pull the turbo to inspect and and see a large piece of metal stuck in the exhaust impeller. I wiggle the turbo and it falls out the bottom of the turbo. I pull the compresor of and the impeler on the intake side looks perfect. I wip it back on and its works fine no oil leaking seems fine. So I drive it for the first time with the new stock engine and the car feels like it has 120HP and is very slugish and slow. Is it possible the turbo is shot? Could the turbo be acting as a huge restriction now and the other turbo is boosting fine to 5 pounds but making no power? Tial wastegates are set at 5 pounds and working perfect. The compresor side is perfect but i didn't pull the exhaust housing of the turbo I just looked at the exhaust wheel it looked fine. I checked the obvious intake leaks loose hose clamp etc. The turbo still does not leake oil at all and spins fine when idling. I just have the FAST demo running the car it should run ok with it and it idles pretty good. I'am getting ready to send the turbo out to be looked at. The car seriouly only makes about 120hp and won't even spin the tires in the rain. I have the wastegates set at 5# to be safe and when you rev it in 1st gear it goes up to 5# on the gauge and stops like it should but car is a pig my lumina would beat it.

I just thought if the turbo was shot it would leake oil or the impeller wheel would be damaged or locked up?


__________________

 

You weren't clear… are you actually getting 5psi boost? If you are you can pretty much assume that both turbos are working (if one wasn't then you usually wouldn't have any boost). Also, unless you've got a serious tuning or engine problem it should be reasonably fast with 5psi…

 

yes I'am getting 5 psi. Your correct it should run decent but its a total pig. Maybe I have a big sock in my intake. I'am going to do a compresion test next maybe the engine is junk.

 

I think we may have figured it out. I pulled the turbo exhaust housing of and its perfect, turbo is fine. After talking with my buddy who dropped the distributor in, he thinks it may be of a tooth or two. He pulled the distributor and put the new one in and couldn't get it to drop in the same place. So today were going to pull the distributor today and put the car at TDC and drop the distributor back in the car. Hopefully this is our problem.

 

car is fixed, distributor was of two teeth. We ran the car tonight briefly only shifting at 4k and getting 3 pounds of boost on the gauge. Tial wastegates have 5 pound springs. I think with the large FMIC and steath ram intake it loses a pound or so on a bone stock L98. Car ran good, hard to say but similar to a LT-1 car stock. Going to get the 8 pound springs and try that.

 

Not a good idea running a boosted car without 100% knowledge of timing.

 

I'll say

howd you set the timing this time if you didnt know the dist was off in the first place?

 

Um, my stock L98 (cat back and cold air) runs 13.5's at 100mph… do you know of an LT1 that runs faster with similar mods? My LT1 runs 13.0@106.9, but that's with 4.10 gears and a bunch of minor bolt ons… I'm pretty sure that my L98 would runs faster times with similar bolt ons, gears and the T56

 

one of the faster stock L98's i have heard of

makes me want to throw my car off a parking garage.

 

My buddy and I droped the distributor in this fall we screwed up. This is why I decided to start with 5 pound springs in the wastegates just to keep things safe. I was just using my 93z28 M6 car as a reference. I'am just happy to get the car up and running. With just 3 pounds of boost I'am surprised it ran very well at all. I never claimed to be an expert my any means but since I turned 16 and got my first camaro I have beeen hooked. I guess I got a little ambitious with this project but its a lot of fun.
In the last 1.5 years I have learned a ton about these cars and would be lost without the internet as a guide. In State College PA there is zero people who have any understanding on late model EFI cars let alone turbos. I will run the car at Beaver springs dragway mid March when they open.

 

Your newer L98 has a better cam and a few other improvements from the factory (I believe that my '87 was factory rated at 220 or 225 where yours is 245hp), I'm running a stock long block, stock manifolds, stock converter, transgo shift kit (mostly because the tranny wasn't shifting into 3rd at WOT at all before I put that in, the shifts still aren't right now, but at least it shifts… I'm just going to have to bite the bullet here eventually), stock gears and a messed up posi (I welded it into a spool over the winter, but haven't run it that way yet. I'm tired of rebuilding it). I've actually run what I consider more impressive times in lesser f-bodies with stockish setups, like a 13.4@104.5 in a 305TPI/5 speed Formula (pretty much the same as my current L98 but with edelbrock TES headers and dynomax cat back), 13.89 in my Crossfire 305 with a stock long block, headman headers, home made exhaust and TB mods (it still ran high 14's with 2 wiped intake lobes and over 150K miles on the stock drivetrain with 3.42's from my '97 TA, which actually slowed it down).

Like I said, lets make sure that everything is right with your car and I'm sure I can get it to run mid to low 13's at capitol (probably with you driving, definitely with me if you'd let me, but I'm betting that you'll have a big weight advantage over me…)

 

Beaver Springs is a KILLER track, Beaver Bob Rocks… it's about 3 hours from me here, but I know I'll be up there some Saturday early this spring, I think it's in April (a bunch of my friends/jyturbo guys are "renting" out the track, but I'm pretty sure that that doesn’t exclude other people…)

 

I would love to meet you guys if you do rent the track. I have a few ls-1 guys that would go to

 

I don't know how I would remember but if you ask me closer to april I'll be glad to give you details when I know them.