ok, same Series 4 T2 as the "sputtering at steady speed" post.

stock turbo on it. but it has gutted cats, and Dynomax turbo mufflers.

heres the deal: he is making boost while cruising down the freeway at a steady speed. he can also spool up alot just reving the engine. also, if hes in 4th,and floors it, it spools up. each time he gets this thing to spool up, it hits the Fuel cut.

he already has ported his wastegate.

how can we fix this boost creep?

im assuming an external wastegate, but how do we install one on here? does anyone have a walk-thru or how-to for an external wastegate conversion???

chris

 

you can also get a fuel cut defender...that might help...what does the boost cut feel like? like the sputtering? or does the motor slow down?

 

the FCD wont stop the boost creep, in fact, it could cause another problem: over boost.

this turbo spools up VERY fast now.

his car is boosting even at steady speeds (when it doesnt sputter). say if he's holding a steady 65, not accelerating, just cruising, he will be boosting 1 or 2 psi.

but, he does hit the fuel cut regularly now. its not like a small sputter, like a spark plug misfire. its the normal fuel cut, and he loses power big time.

we just wanna figure out how to convert this to an external wastegate. im almost positive that it will fix the boost creep.

chris

 

an external wastegate will fix the problem but you need a new manifold, turbo, and the wastegate itself. then you need to control the fuel going to the new turbo as it will be bigger.
$$$

with a ported wastegate and just an gutted exhuast you should not be hitting fuel cut. does he have an intake? TID mod?

do you have a aftermarket boost gauge to confirm the PSI you are hitting it at? should be between 6-8.5 psi on the 87-88, some people get it at either.

if you are hitting it at lower then 6 psi you've got a different problem.

 

yea, hes got an intake too.

dont know about TID?

he doesnt hit fuel cut below 8.8 psi. he just gets up to max boost VERY fast, and then hits the fuel cut.

he also has positive manifold pressure at times when hes NOT accellerating. if hes just cruising at steady speed, on flat ground, he still has positive manifold pressure. im not sure if he's supposed to or what.

but, to get external wastegate, it takes a new exhaust manifold? would a regular turbo kit upgrade cover this? like GReddy, or HKS? theres no way to convert the stock stuff to external?

well, he has to pick between the Power FC, or a turbo kit now....

thanks
chris

 

I'm planning on upgraded to a full 3" on my series 4. I'm also going to gut out the twin scroll and put an external on the rear runner. You don't need a new manifold to mount an external...but you'll need it modified. You'll also need the stock wastegate flapper welded shut. I'm thinking a tial 40mm will be more than enough. Expect to pay round 350 for the tial and probably 100 bucks for mod's to the manifold and a dump pipe for the wastegate..unless you want it plumbed back into the exhaust

 

so we can modify the stock manifold to accept a wastegate?

cuz if we can, that would be easier i think, or cheaper anyhow. who could modify the cast iron manifold to accept an external wastegate?

chris

 

There is no way that without a load the car is boosting... Thats how a turbo works, is when the engine is loading. The only way the car would be producing boost while crusing is if the brakes were sticking and the car was loading up.

Your boost guage is fucked. Get a new one.

 

stock manifold to accept a external wastegate ???
yes or no

 

I was reading the post, and i could not agree more!!!!!

You either are reading the boost gauge incorrectly (different scale than PSI), or your boost gauge is fubared. Are you reading the stock boost gauge????? If so, i oughta slap you. If not, get a new boost gauge. A turbo can not spool unless there is load on the engine. There simply is not enough exhaust flow to compress the intake charge. It's just impossible.

Make sure the wastegate actuator line is secure.... as well as the boost sensor line, what have you...

 

Depends. How much money you got?

 

ya stock guages are NOT accurate.
Does any one know of a write up on porting the wastegate... Is this an easy thing to do?

 

I think he means you can use a drill and drill through the stock manifold, fabricate a way for the external to mount to the flange, and have the downpipe modified again to accept a Y-in pipe that comes from the wastegate.

 

Why not just get an FD fuel pump and a FCD, that should cover the fuel needs with just gutted cats and an intake. And cheaper then modifying your manifold to accept an external wastegate...

 

You have not described anything that resembles boost creep. I suggest taking the car to a qualified mechanic.

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