Boost Creep Fix
Thread Starter
Joined: Feb 2002
Posts: 1,640
Likes: 2
From: Tacoma WA
Boost Creep Fix
Ok guys, this does take some work but it actually results in NO BOOST CREEEP!!!
I've done this on two FC's and both have the same results. With the boost controller turned off, the car maintains stock boost without creeping. Here's what I did.
1. I pulled off the backing plate / flange on the back of the turbo (after pulling off the downpipe just 2 13mm bolts are holding it on).
2. Disconnect the wastegate actuator from the wastegate door so the door can swing freely.
3. This works better with the turbo out of the car, but you need to note where the wastegate door hits the backing plate. When you find it, grind the hell out of that spot on the plate and on the wastegate door. I put a spot of black RTV on the spot i suspected the door was contacting the plate and when it appeared on the plate, just ground it down. I didn't go more than 1/2 was through the plate, but here are the results.
I've got a few picts of how far the door opens before and after. You can see the locations I ground in order to get the door to open further.
The first car I did this to has been running with no issues for the last year. The second car was just purchased and this was a precautionary measure I implemented after the rebuild.
http://tooyoungto.servebeer.com/images/turbogrind
I've done this on two FC's and both have the same results. With the boost controller turned off, the car maintains stock boost without creeping. Here's what I did.
1. I pulled off the backing plate / flange on the back of the turbo (after pulling off the downpipe just 2 13mm bolts are holding it on).
2. Disconnect the wastegate actuator from the wastegate door so the door can swing freely.
3. This works better with the turbo out of the car, but you need to note where the wastegate door hits the backing plate. When you find it, grind the hell out of that spot on the plate and on the wastegate door. I put a spot of black RTV on the spot i suspected the door was contacting the plate and when it appeared on the plate, just ground it down. I didn't go more than 1/2 was through the plate, but here are the results.
I've got a few picts of how far the door opens before and after. You can see the locations I ground in order to get the door to open further.
The first car I did this to has been running with no issues for the last year. The second car was just purchased and this was a precautionary measure I implemented after the rebuild.
http://tooyoungto.servebeer.com/images/turbogrind
plus this has been tested and proven to be false. it is solely dependent on the mods to the car and the turbo.
i'll bet you pinks if i just backcut where you said it on my hybrid Turbonetics S4 turbo with a stock sized wastegate it would spike to 20+ til the turbo blew to bits or the motor whichever first..
you need to state mods to be clear or someone may try this thinking they are safe and BOOM! you have one pissed off forum member chasing your *** around...
i'll bet you pinks if i just backcut where you said it on my hybrid Turbonetics S4 turbo with a stock sized wastegate it would spike to 20+ til the turbo blew to bits or the motor whichever first..
you need to state mods to be clear or someone may try this thinking they are safe and BOOM! you have one pissed off forum member chasing your *** around...
I'll agree with Dr. Ifter that cutting out the back-plate helps.
I've done it twice (although also doing heavy WG porting), and I think it makes sense. Not only that, it takes about 3 minutes and it definitely doesn't hurt.
Here's what I did:

But I also did this (with a heavy "back-cut"):
I've done it twice (although also doing heavy WG porting), and I think it makes sense. Not only that, it takes about 3 minutes and it definitely doesn't hurt. Here's what I did:
But I also did this (with a heavy "back-cut"):
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answer the question n00ber!
i am always curious how other people's porting turned out with the stock flapper, i only got about 1-2psi of creep with my .60A/R Turbonetics hybrid with the stock flapper ported as large as i could manage it.
i am always curious how other people's porting turned out with the stock flapper, i only got about 1-2psi of creep with my .60A/R Turbonetics hybrid with the stock flapper ported as large as i could manage it.
LOL, I sold that turbo, but was able to keep it around 9psi with N/A rotors, street-port, 3" TID, 80mm full exhaust etc.
Screw a new flapper for the stock turbo... Some people just don't know how to do a good WG port.
Screw a new flapper for the stock turbo... Some people just don't know how to do a good WG port.
Anybody who's tested the wastegate actuator with compressed air knows that grinding back the backplate does virtually nothing, because it's the stroke of the actuator that limits how far the wastegate flap can open. The flap does normally hit the backplate, but it can only travel ~1mm further before the wastegate actuator spring is fully compressed. That tiny bit of extra travel will barely improve wastegate flow, if at all.
Thread Starter
Joined: Feb 2002
Posts: 1,640
Likes: 2
From: Tacoma WA
My mod list:
HKS full turbo back (dual system) 3" split to (2) 2.5"
S5 Turbo (stock with backing plate mod)
FMIC
HKS AIC with 2 400cc injectors
HKS EVC III set to 12psi
Intake with stock TID
Reminder: Even with the boost controller off, I don't creep at all.
As for pulling off the turbo to do this right, for those of you that look at the pics, you can see where the plate was cut and duplicate the cutting in the similar area on your plate.
HKS full turbo back (dual system) 3" split to (2) 2.5"
S5 Turbo (stock with backing plate mod)
FMIC
HKS AIC with 2 400cc injectors
HKS EVC III set to 12psi
Intake with stock TID
Reminder: Even with the boost controller off, I don't creep at all.
As for pulling off the turbo to do this right, for those of you that look at the pics, you can see where the plate was cut and duplicate the cutting in the similar area on your plate.
Originally Posted by Dr. IfTeR
S5 Turbo
Its the S4 guys who really need to worry about creep.
Originally Posted by classicauto
No WONDER it worked, the S5 wastegate shouldn't need much help to work properly.....telling it "naughty wastegate" sternly a few times is usually enough to stop boost creep on an S5.
Its the S4 guys who really need to worry about creep.
Its the S4 guys who really need to worry about creep.
Originally Posted by NZConvertible
Anybody who's tested the wastegate actuator with compressed air knows that grinding back the backplate does virtually nothing, because it's the stroke of the actuator that limits how far the wastegate flap can open. The flap does normally hit the backplate, but it can only travel ~1mm further before the wastegate actuator spring is fully compressed. That tiny bit of extra travel will barely improve wastegate flow, if at all.
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Your FC is sick.
ahhh...

