so i have an s4 tii swap in an n/a chassy. its rebuilt with 2500 miles on it. i have an safc and an LC-1 i have a "short ram" air intake , ported waist gate on an s5 turbo. and a full racing beat revII exhaust. pretty straight threw.
when i am in 2nd gear and get on it i do tend to stay at 10psi. but when i get on it in 3rd or 4th i shoot to 15+, i am not positive but i can look at my safc that is tapped into boost sensor instead of TPS. and it read 100% throtle last peak. 86% is 10. and 64% is 5. so 100% is anything over lets say about 14psi. who knows what psi i hit when that happend......

i am not sure what to do. i am not sure that a greddy profec b spec II will help me much. i do have one and i have yet to hook up the solenoid, mainly because i dont drive the rx7 much. and i am still reading up about the profec. i know it cant really lower the boost but it can help even it out and in cases help controle boost creep.

bdc told me that my engine is most likely breathing to much. meaning there is no restriction on my intake. and there is no restriction on my exhaust. the turbo will spool up faster then the waist gate can get rid of it. which makes sence to me.
i was thinking of installing the profec, and also installing a restriction infront of my AFM. piece of plastic infront of my 3'' adapter

what do you guys think?

 

just port the wastegate. stock wastegate is too small which is causing your creep, espically on s4. if u dont wanna port put a restriction in your exhaust like a converter.
boost controller doesnt lower boost, it increases it and in a under control state.

 

yeah it is ported as much as it can be. i forgot to say that in the body . but i said that in the title.. rotary fumes make me think not so clear.... lol

and as far as boost controlers.... idk if you know that they stablize boost too....well at least for buddy it stopped her boost from creeping. but she doesnt have a free flow exhaust.

 

you say the wastegate is as ported as can be... did you go so big you had to weld on a larger door? i have never had an issue like this after properly porting the wg and i have used 3.5" straight exhausts on ported engines

if you indeed did go as large as physically possible on the wastegate and are still having incredible creep problems then throw some race gas in that bitch and let it ride! haha j/k

 

man i got to elaborate on every detail... dont i. ok its as ported as it can be on a stock flapper. i did not personaly port this waist gate. i bought the thing and took it apart and looked at it.
but any way..... maybe its just not ported enough... but what about that restriction i mentioned.

 

installed a restricting piece of plastic between 3'' adapter and air flow meter to reduce air flow from 3x3'' square to 1x3'' square

the results were amazing, and very restricting.

in 2nd gear i would bog out any where near 5psi. in 3-5 gear it would bog out at 5-8psi.

i am going to increase the size of the slit in the piece of plastic.

 

weld wastegate shut buy aftermarket manifold with external wastegate flange buy external wastegate problem solved.... just ask Jake.

 

hmmmmmm... interesting.... becaue i love the stock turbo.... hmmmmmm. but that means i have to hack up the poor racing beat down pipe!

 

yes you do have to be detailed man, and by doing so i found your problem. if you only port to the stock size of the stock flapper it's not going to do a damn thing. you have to port to the size of the wall surround the lower half... usually about 36 - 38mm hole (you can go bigger). weld on a new door and boom, boost creep should be gone WITHOUT using restrictions


the ultimate best way??? block off the wastegate as mentioned above, BUT weld a port off the actual turbine housing that leads to an external wastegate.

 

oooooooooooooooOOOOOOOOOOOOooooooooooooooo i like that thought better......

and as far as the porting. yeah the car it came off of had a similar setting as mine did but less compression and he never had boost creep. oh well..... i'll start doing all the **** listed above in order from cost and difficulty.

 

get on it! boost creep kills!!!

 

yep...

 

Some porting tips that may give you some ideas:

http://www.aaroncake.net/RX-7/s4wastegate.htm

http://fc3spro.com/TECH/HOWTO/KWG/kwg.html

 

deffinantly will be doing this... thanx. i also got a link for www.1300cc.com they have some cool writeups