possibly, though i really think it's doubtful at this point.

 

what size wastegate is it

 

tial 35mm

 

the wategate not to big
But for some reason am thinking its something with the wastegate bleeding to much boost off
Like the vacuum line to small going to the wastegate or something along of the lines of vacuums or boost controller vacuum line to small

 

no thats not it, it does it at wastegate pressure as well as with the b/c on. If the line were too small, it would deliver too small amount of pressure to the gate, thus it would over boost, which it does not do. The line is adequately sized. I really wish I had the dyno chart, I could show you what I mean. Even when it loses that almost-one-psi at wastegate pressure, the power and torque drops off dramatically beyond 6500rpm, more than what a loss of one psi would do. It's as if the motor is injesting more air than the charge pipe can physically deliver, thus creating a vaccum in the intake manifold and lower boost registered on the gauge. This would also explain the significant loss in power.

In case anyone was wondering, the ignition system has been traded out tip to tail for known good items as well. I assure you no stone has been left untouched! I've been working with this car for close to 6 months, helping him through a myriad of problems, but one thing has always been consistant, and that's the loss in boost pressure and lack of top end power. Unfortunately, one thing or another has always sprung up and prevented us from really investigating the problem until now. God i wish i could weld I'd make the damn pipe myself!

 

are you running stock cams i seen stock itr cams do somthing like that and do you have cam gears where are they set

 

that was gonna be my next suggestion. what cams is the car running and have u tried adjustting them?

 

doh! forgot to tell you that, stock b16a cams, car has skunk2 cam gears that we adjusted all over the place with no gains or change to the problem at hand.

 

...interesting topic. I still think could be either two things:
(1)It hasn't been mentioned but it's so basic that I'm pretty sure its working and you would've posted about it if it wasn't.
(2)The other reason is what you & ffgeoff disagreed on, but I still think it is The Problem.

 

Got an extra intercooler laying around? Might as well try swapping that out too, seeing as you're swapping everything else out.

 

What size exhaust

 

open downpipe, 2.5 inch

 

bov opening?? i know u said no boost leaks, adding fuel to the fire...

 

john whats the word on the chip? i think if u ship it out overnight it will fix the boost drop problem.

 

Here is a situation I had...

On a turbo system that I had built with a T3/60-1 a couple of years ago, I built everything, Im certain that everything was built well and was working perfectly. while tuning the car, I would drive around and as I started to build boost the car would get up to about 3-4 psi and the boost would drop to 0. The a/f was fine for building boost, not too lean or too rich.

The problem turned out to be a poorly balanced turbo. My guess is that when it gets to a certain speed there is a harmonic that it cant get past and causes it to lock in at a wheel speed and cant provide enough flow for the higher RPM demands..

I would try to swap the turbo and try again.

just a thought

jason

 

I would put my $$$ on it being the turbo. I bought a turbo from evergreen turbo last year and it just never pulled like my smaller turbo I had on before it. I ended up buying another turbo from majestic and the problem went away. I never had the car on the dyno so I cannot help you there. I think between swapping out the turbo and using 2 boost guages one at the turbo and the other at manifold you will find the problem. Btw how did this turbo work on the first car it was on? Also I don't think its the 2.25" piping. Up until 4-5 weeks ago I had the most bullshit charge pipe (crush bent from a muffler shop) and it worked just fine. I'm pretty sure my new piping gave me a little more power but I made good power with teh other one.


[Modified by hybrid901, 4:36 PM 1/31/2003]

 

Vaportrail, have you solved the problem?

 

I wanna say yes but....the car hasn't hit the dyno yet.

The car inexplicably exploded a stock retainer, dropping a valve. This kid has the worst luck in the world! A new head, with skunk2 components was installed, and odd vaccum line was replaced. The car was driven to us, and the charge pipe was replaced. Its holding boost on the street...but it would do that before sometimes as well. The jury is still out for another week until he hits the dyno again.

 

i am by no means an expert with turbos, but i would reccomend installing a temp sensor in the charge piping, say one before the IC, one after, datalog it and compare against the power curve. i think if the pipes are too small you'd get higher temps in the whole system as after that RPM range. as you would reach the effective flowrate of it.
just my 2cents
stan

 

This is a pretty labor intensive way to troubleshoot (and requires a second car) but have you tried swapping each component (manifold, turbo, IC) into another car that you know works perfectly fine? That way if you know that part works fine in another car, then you can rule out that item as having problems. Once you rule out the turbo parts as all working fine, then that leaves only the engine as a possibility. I know the tests come up fine, but those tests coming out okay don't rule out the possibility of the engine being the problem.

Not the most clever way to figure things out but sometimes the part you think is working fine is actually the culprit.


[Modified by Rain_man, 10:12 PM 2/22/2003]

 

What you described is a classic case of an intercooler that is too small (or maybe slightly plugged). Need to measure inlet temps at high speed.
You might try a gsr or type r cam to see how it reacts, also.

 

what injectors are you running?