Slow spool, Bad response, Losing to a 327?

[Roc87]

My Iroc is getting closer to being completed (are they ever actually finished?). But I'm running into problems. I've had these problems for a while, but never really bothered me until tonight when I was on my way to a show and pulled up next to my Dad, with his '30 5 window ford coupe with a Vette 327 in it. I should have SMOKED IT! but I only kept up with it......

I seem to have vacuum leaks, but after using 2 cans of carb cleaner I can't find any. Gauge only shows 8in of vacuum, (Bad brakes!) and it spools really slow. If I program my chip for 38# injector constant it seems to idle better, but if I actually program it for the 009's, The check engine light comes on at idle for (Rich or lean, I don't know which yet) I don't have the exact numbers off Direct scan because "Crash" is still borrowing it......

As a side note, my '87 GN runs a WHOLE lot better even with the smaller turbo, stock stall converter and lack of alcohol...
Iroc parts are described in signature, Engine had roughly 69k miles when pulled out of wrecked T-Type (Sat for over 2 years before I bought it) HELP!!!! If there were a shop that knew these cars that was close, I would take it, but since I don't live on either coast, there really isn't......

 

[Roc87]

BTW, I only ran a 14.2 @ 103 mph at the strip..........

GN with stock turbo, stock stall, and only 19# with 24° ran a 13.2 @ same MPH in Vegas.........

 

[Roc87]

TTT

 

[WIKEDV6]

8-inch vacuum seems too low, how is the intake gasket? Any holes in IC/ IC hoses? Try disconnecting the brake vacuum and see if that helps to bring the vacuum up. Is there a big cam in the car? Was the 86 motor in a fire before you pulled it out? Is your fuel regulator good? Any wholes in the hose between the turbo and the mass air flow?

Good luck
Prasad

 

[SuperSix]

Check ALL of your vacuum lines, and check for exhaust leaks...

 

[badboy86gn2]

"burn it" but dont forget to take it out of the garage first

no just kidding


dont stress i know that car will run its just like i said 2nd feels boggy and third feels like it got hit with a baseball bat

its just a matter of time before you figure it out and on this board it shouldnt take long

JOhnny

 

[Lbraucht]

i have a pt51 also and i don't think it runngin to where it should be either i don't know whats wrong with the car.
-Tim

 

[Roc87]

I should check intake gaskets, haven't yet. Brand new silicon hoses between MAF and Turbo, and also from Turbo -> intercooler -> throttle body. Car that engine came out of was in a HORRIBLE wreck, but not burned, although battery acid went everywhere.......... Here's a strange thing, Vacuum reading doesn't change when unplugging the vacuum line to the brake booster, not even 1in! Should I try to find somebody with a "Smoke Generator" to look for a leak? Or a compression test, leak down test etc.........

Lbraucht, I've heard PT51 supposedly spool slower than a 61 or even a 54, but my friend "Crash" has had a PT51 with a small stall run a 12 flat here at 5,000 elevation........ So we'll see what's going on sooner or later. (My 51 spooled faster on my GN with the stock converter than it does in the camaro with the 3200 stall )

 

[Quick6'n'-K.C.]

oring on turbo compressor housing?

do a leakdown test on the cylinders, could be leaking out of a fire ring??...

8 inches is rediculously low..

boost gauge leak?

hope you find out what the problem is...

BW

HTH

 

[Roc87]

I FOUND MY PROBLEM!!!

I have an intake gasket leak on the drivers side rear (4&6?), so besides buying a felpro gasket part #MS96033, and a set of valve cover gaskets, what other gaskets do I need? While I was in there, I'm thinking about replacing the lifters and valve springs. What's the opinion on that? THANKS!!!

 

[Roc87]

TTT

 

[mgmshar]

Generally, it's not a good idea to put new lifters on an already broken-in cam. It can work, but the risk of wiping out a lobe is really high. Unless something is wrong with a lifter, I would leave them alone.

Valve spring replacement is never a bad thing in GN engines, if the stock springs are still in there. Most use springs with some type of dampers (usually flat ribbon dampers inside the spring). The norm is to go with valve springs that have about 90-100 lbs. pressure with valve closed. I ordered a set of these from Kirban's, and they've run quite well. I think the consensus is that 100 lbs. will not hurt the cam lobes, as long as the cam is already broken in.

Also, don't forget to replace the intake valve stem seals while you're in there. Seals only go on the intakes - no seals are used on the exhauts.

As far as a parts list, somebody else will have to help you there. Basically, you'll need valve cover gaskets, intake gasket, new O-rings for the fuel lines that you'll have to remove, valve springs, a valve spring removal tool (available at many Buick vendors), and valve stem seals. I'm sure I'm forgetting some things, but this will get you started.

 

[Roc87]

Thank you!