So the new turbo has been installed and i'm still having the same problem.
The car pulls hard under boost until the wg acts up.It happens shortly after the wg opens.boost goes up to 7psi and holds steady, the wg opens and everything is still fine, then the wg changes tone (from a steady sound to a cavitating sound) and the car starts surging...feels like it's bouncing off the rev limiter but it's not.It happens about 6k rpm.The air/fuel ratio gauge is in the rich, fuel pressure is holding steady,and boost is constant.I have no clue where to start.The car pulls hard up until this pointand then it feels like it hits a wall....any sugestions...thanks..

btw it's a b16a,garrett t3t4 .57/.63 drag manifold and tial 35mm.
8:1 fmu,255lph fuel pump h/p,310cc injectors,msd 6al,ngk plugs.It never did this with the old turbo and internal wg...but it did do this with the old turbo and tial wg....i'e changed vacuum sources (before and after t/b) and still happens..

 

vtech? err..vtec?

 

What about it? tell me more

 

try setting it lower if see if it helps, if not I'd get that thing hooked up to a wideband. You might be extremely rich.

 

I have no way of adjusting it...i think it may be rich too, but i cant explain why it didn't do this with the internal wg...although boost did drop off in the upper rpm with the old turbo

 

so you mean, everything stayed the same from the settings like fuel from before? Is the turbo bigger now than before?

 

yeah everything is the same...only change is the turbo and wg...
the old turbo was a small t3 (.42/ .48) and the new one is a t3t4 (.57/ .63)..but this happend with the old turbo so it's not the turbo......

 

what are you using for your fuel management? get that thing hooked up on the dyno asap. I'm sure your making way more power than the old setup. I thought you said it didn't do this with the "internal one"?

 

310cc injectors,8:1 fmu, high pressure fuel pump,aem 1:1 fpr.
It didn't do this with the internal wg..it did do this once i installed the tial....
old turbo unhooked internal wg runing tial = problem
old turbo internal wg no tial = fine
new turbo tial = problem

 

how much more boost did you get after switching to external?

 

none.
I'm runing a .45 bar spring (about 7psi)
before that i was runing 7psi but it would drop off to 4.5psi or so....

 

I'm having the same problem with the same wastegate! I have a .65 spring and it climbs to .73 and then violently dumps pressure. This is completely unconnected. When vacuum line is connected it climbs to .38 and then releases normal. My boost controller allows me to tune to .71 where it stays smooth. I'm thinking a bigger spring. Are you using a boost controller?

 

your symptons sound like you're running extremely rich on the top end. thus having that violent surge.

the wastegate really has nothing to do with the car feeling like it hits a wall. unless the boost guage is reading 0 at that point.

the only portion the wastegate controls is to regulate boost.

if you have something to tune with tune down the fuel.

my car is doing this right now also but that's because it's running extremely rich from the cold temperature.

 

no boost controller....

 

I know the wastegate just regulates the boost, but it only happens with the tial wg hooked up.... thats why i connected the two.....(tial and the problem)...I'm not blaming tial or in any way trying to say tial gave me a bad product (just wanted to get that out of the way..)..

Do you think that i would be runing that rich with my set-up?
310cc rc's, 8:1 fmu, holley 255lph h/p fuel pump, aem 1:1 adjustable fpr, idle fuel pressure of 38psi.
so a total of 9:1 rising rate.

I just recently switched from my 6:1 fmu to the 8:1 because i was runing lean and had a slight detonation at about 5psi of boost.I'm just affraid to switch back to the 6:1 because i won't be able to hear if it's detonating or not.....
I changed from zex plugs that were new (1000 miles) but all black to a set of my ngk's that i took out when i put the zex in.It helped the problem a little, it's able to rev further before the problem happens.I think that i may replace my cap and rotor tonight to see if it helps...it's either to much fuel like you said or poor spark and it's not able to ignite the mixture well enough so it misses....thanks for everybodys help I appreciate it, keep it coming...thanks

 

Another thing is my bov....it used to make the usual sound now it chatters when it releases.Low boost it still sounds the same but 3+psi it makes chattering sound when it releases, any idea's? it's just a bosch saab bov...(over pressure valve)

 

did you reset the ecu?

just a thought

 

Nope, usually when i reset my ecu it makes the car run richer for a while until it learns my driving....

 

definitely a problem with spark or fuel i believe.

since you say using the ngk's allowed the car to rev higher before hitting the wall.

you may need some new wires, cap, rotor, etc.
try to get the car diagnosed by a pro. near your area. that's your best bet.

 

I swapped the 8:1 fmu for a 6:1 fmu and the car pulls hard all the way to redline.So it was not buring all the fuel.Thanks for the help guys ....

I'm still skeptical about using the 6:1 because i was runing lean before, thats why i switched to the 8:1...
I'm going to replace the cap, rotor, and plug wires then try the 8:1 if it boggs again then i will just run the 6:1...thanks again...

 

I'm using 450cc inj with vafc hack and I do run pretty rich because I don't really trust my A/F gauge and don't have access right now to a wideband. I never thought it would be a fuel problem. Why is the cold causing you to run rich? Wouldn't cold air cause a leaner condition, if any....that's what the IAT sensor is for.

 

just because you are not running more pressure does not mean you are not running more volume. you were running a strait t3 turbo and now you are running a t3t4 hybrid capable of much more than your previous turbo. think of it this way... blowing air through a straw at 10psi, now blow air through a tube that is 3 inches in diameter at 10psi. which one can flow more volume? now i dont think you changed your intercooler piping but i know you did change your compressor. i dont think your computer knows what to do. strange none the less


[Modified by ffgeon, 6:46 AM 12/28/2002]

 

I thought if anything it would cause it to run leaner not richer....either way it works great now.....the intercooler piping stayed the same....only the new turbo and new wg....

 

thats what i was thinking, that it would be leaner instead of richer. so you got it to work?

 

Yeah, strangly enough it was runing too rich.I just leaned it out a little and problem solved...The car pulls hard to redline now.All i need now it an elbow to relocate my wastegate, and a dump pipe ...then i'm set ...