Fighting boost creep - S4->S5 Turbo swap?
#1
Fighting boost creep - S4->S5 Turbo swap?
Hiya everyone.
Recently, I had my Haltech, exhaust and other upgrades installed.
As soon as I got my car back, I realized there was massive boost creep. I hit 14.6 once halfway through third gear, and usually 13 or so in second gear.
So, I decided to try to resolve this issue with a bandaid until I can afford to swap it all out (FMIC and T04).
Would an S5 turbo, and a heavily ported wastegate be enough of a step up to combat my boost creep?
My ideal boost would be 12psi on the dot, but not much higher.
Would buying someones used S5 Turbo and Manifold (Is that all I would need for the swap?) and porting the new wastegate be enough of an aid against boost creep?
Since I'm running a 3" exhaust, could I use a smaller gasket (2.5" or so) to create extra backpressure against the turbo if I'm still experiencing boost creep?
Which one should I try first? I'm desperately trying to fix this problem.
Recently, I had my Haltech, exhaust and other upgrades installed.
As soon as I got my car back, I realized there was massive boost creep. I hit 14.6 once halfway through third gear, and usually 13 or so in second gear.
So, I decided to try to resolve this issue with a bandaid until I can afford to swap it all out (FMIC and T04).
Would an S5 turbo, and a heavily ported wastegate be enough of a step up to combat my boost creep?
My ideal boost would be 12psi on the dot, but not much higher.
Would buying someones used S5 Turbo and Manifold (Is that all I would need for the swap?) and porting the new wastegate be enough of an aid against boost creep?
Since I'm running a 3" exhaust, could I use a smaller gasket (2.5" or so) to create extra backpressure against the turbo if I'm still experiencing boost creep?
Which one should I try first? I'm desperately trying to fix this problem.
#2
What R U thinking self?
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Try porting the WG on your current turbo first. Sound slike you are not hitting much more than your ideal, port it as big at the cover and it should be fine.
#4
What R U thinking self?
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If you plan on buying a FMIC, and a T04 ... then why **** money away on a S5 turbo now? Not sure if it would even cure the problem .. but either way sounds like pissing into a stiff breeze. Put a more restrictive intake on the car until you can afford to complete it right, ... and be done with it.
-Robert
-Robert
#7
With the RB turboback and the 3'' TID I can understand your hellish boost creep. I have a s4 turbo with the wastegate ported to the max and I still get creep in cold weather to 13 pounds. A series 5 turbo/manifold with ported wastegates should be able to hold boost under 12 pounds.
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#12
I'm a boost creep...
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The stock flap is very small, but swapping a bigger one on allows you to port the wastegate much bigger. Any turbo shop will be able to do this. For a DIY solution read the thread in the archives.
#13
Sounds great. I'll give my guy a call on Monday and hopefully arrange something like this.
After doing this, is my boost going to 'go up' to whatever value it was creeping to before, or is it going to keep it in it's place?
After doing this, is my boost going to 'go up' to whatever value it was creeping to before, or is it going to keep it in it's place?
Last edited by Wompa164; 11-15-03 at 06:07 PM.
#14
Compression Tester Guy
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I just finished porting the stock wastegate on my S4 turbo and installing my RB 3" turbo back exhaust. I had a stainless steel washer welded onto the stock flapper to increase it's size and I can keep the boost down to 5 lbs. Sometimes it'll creep up to 6-7 but by then I'm going way too fast. I am still using the stock intake so that's also helping keep boost down. I did everything myself (except the welding) and I'll see if I can get a pic of my new flapper up.
#15
I'm a boost creep...
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Originally posted by TwistedRotors
I had a stainless steel washer welded onto the stock flapper to increase it's size...
I had a stainless steel washer welded onto the stock flapper to increase it's size...
#16
Compression Tester Guy
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I got that idea here on the forums. The washer was convenient and it welds nicely to the stock flapper. I like that because it pivots and moves like the stock flapper and makes it easier to seal. Still working on getting those pics, they're still on the camera and then I gotta resize 'em. someday they'll be up on my site.
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Compression Tester Guy
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Thanks for the compliment. No problems or side-effects for the past month. I also removed the twin-scroll flapper and actuator while I had the turbo out but with the RB exhaust it still spools up really quick. The only time I've gotten it to creep past 6 psi was in 5th gear, cold night, going way too fast...it hit about 7 psi. A more open intake would probably make it creep a little more.
#21
Is boost creep always a bad thing? I mean, if you are able to supply the proper fuel, would it be ok. I have a series 4 turbo and will be running a full 3 inch exhaust and freeflowing intake. I will be running a Microtech with 720 secondaries. I did port the stock wastegate to as big as the stock flapper would allow but if I do boost creep, it wouldn't be bad right? If I can supply the proper fuel, wouldn't the creep just give me more power?
thanks
thanks
#22
Originally posted by RotaryRevn
Is boost creep always a bad thing? I mean, if you are able to supply the proper fuel, would it be ok. I have a series 4 turbo and will be running a full 3 inch exhaust and freeflowing intake. I will be running a Microtech with 720 secondaries. I did port the stock wastegate to as big as the stock flapper would allow but if I do boost creep, it wouldn't be bad right? If I can supply the proper fuel, wouldn't the creep just give me more power?
thanks
Is boost creep always a bad thing? I mean, if you are able to supply the proper fuel, would it be ok. I have a series 4 turbo and will be running a full 3 inch exhaust and freeflowing intake. I will be running a Microtech with 720 secondaries. I did port the stock wastegate to as big as the stock flapper would allow but if I do boost creep, it wouldn't be bad right? If I can supply the proper fuel, wouldn't the creep just give me more power?
thanks
Above about 12psi or so, you're putting damage on the turbo, and run the risk of detonation with hot intake charges from inefficient intercooler.
#23
I'm a boost creep...
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Originally posted by RotaryRevn
If I can supply the proper fuel, wouldn't the creep just give me more power?
If I can supply the proper fuel, wouldn't the creep just give me more power?
I have heard of cars tuned to run high boost making more power when the boost was turned down because the mixtures could be leaner and the ignition could be more advanced.
The amount of boost you run should be governed by your turbo. Keep boost where the turbo works best.
#24
Ok, that makes alot of sense. I guess I just gotta get my engine up and running and see how bad the boost creep is gonna be. Or I could take my turbo apart again and get a new flapper welded on while it's off of the engine.
thanks for the replies
thanks for the replies
#25
Hmm.
My man said this kind of job would probably take 6-8 hours.
That's like $300-$400 bucks at $60/hr.
I don't have that kind of money. That's 1/3 - 1/2 of a new intercooler or lots more things I need more.
What else can I do, now? Just put a bigger restriction on the intake?
My man said this kind of job would probably take 6-8 hours.
That's like $300-$400 bucks at $60/hr.
I don't have that kind of money. That's 1/3 - 1/2 of a new intercooler or lots more things I need more.
What else can I do, now? Just put a bigger restriction on the intake?
Last edited by Wompa164; 11-17-03 at 08:32 PM.