How to deal with boost creep.
 

Hey guys,
I really want to run a DP and MP on my Tii, but i'm worried about boost creep. and since i have an S4 it is even worse. how ever i got a great idea yesterday, until i upgrade my turbo and mani to a ported s5, could i run with a silencer in my n1 exhaust. would this reduce flow enough to keep boost creep at a controllable level with a 2.5in dp and mp and a 3in exhaust? thanks

Do you already have the silencer? I've heard that it really depends on what you put in... Like, some silencers restrict the airflow more than others. I bet if you got a super ghetto E-bay silencer you'd stifle your exhaust flow a bit...

If you have the silencer, just try it and find out.

Honestly though, I think the only way you can *really* stop boost creep is by porting your WG. I did this a couple months ago and it wasn't too difficult. The biggest hassle would probably be removing the turbo to get to the WG. After it's removed you could probably be done porting it in about an hour or so (if you've got the right tools).

Don't be intimidated by the turbo removal, it's not too difficult. You take off the DP, remove the accesories on the front of your motor, remove the 4 turbo to exhaust mani. bolts, the 2 oil lines, coolant line, BOV etc. then just ease the turbo out through the front of the engine bay... I don't know, good luck.

P.S: what psi are you boosting to?

ebay silencers are mostly glasspacks like the mufflers, straight through and often are cheap but flow better than good quality ones, just because they are cheap don't assume they flow like crap. my $200 exhaust is loud as hell and flows probably better than most exhaust systems out there, usually you compromise sound quility with air flow so most quieter/deeper exhausts flow worse than cheap ass setups. don't get me wrong, the difference is hardly noticable in the power differences though. a catalytic converter is the best restrictor and muffler you can put on.

for the poster of the thread: don't assume a S5 turbo will cure the problem either, the wastegate on both series turbos is too small to accomodate most any modifications to intake and exhaust flow. porting the wastegate is your only option to cure boost creep.

first off I think he's talking about the kind of silencer you put on the very tip to make it quieter..

second he said he was going to port the S5 turbo

my opinion... I don't think it would work that well but you should be fine. I was boosting upwards of 17 psi before I ported mine, and my motor is fine :p: (I did blow my turbo though, but that was also due to a kinked coolant line)

karack you need to read posts better :p:

-Myk

i do have a habit of not reading through fully... :D

It may work, but it would probably be good to hear from somebody who actually tried it.

Why don't you just upgrade your turbo system first? No offense, but it seems pretty dumb to go thorugh all the work and expense of upgrading the exhaust, only to plug it up so it acts like your old exhaust.

I believe that the S4 turbo's wastegate, AFTER porting is better than a ported S5.. heard that somewhere. Confirmation?

well with stage 2 porting, TID mod and 3" turboback(no cats, resonator and fart can only) i am able to hold 5psi with a ported S4 wastegate. ;)

I have no problem with boost creep and I'm running a S4 T2 with a 80 mm dp & a corksport 80 mm midpipe going to a single - resonator - muffler- muffler with a stock flapper ported wastgate. BNR hybrids run 25 mm wastegates. Its louder than my RB turbo back.

I'm running a 2.5" DP, 3" cat-back and a 3" TID, and get a solid 6psi thanks to this wastegate port:

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/serious-s4-wastegate-porting%85-343788/ :)

Oh, man you read my mind. If you need one of those butt plugs to make your exhaust streetable, you have a crap exhaust... ;)

its true

not true

Try putting back the stock air cleaner asembly.
This helped me out. :D

Thats what i dont understand, that has to be only if the material around the port is machined out and there is a huge ass flapper. Someone care to explain for me so i understand

This is my way to overcome creep and over-boosting.

http://www.slcrotary.com/driftedfc/B...o_Swap/WG2.JPG

Damn that is hard core! Nice fab work :)

Check out the archieves for NZConvertable's post regarding wastegate porting. I've done something very similar, I welded two washers on top of each other onto the stock flapper. I have a ~35mm wastegate port and there's zero creep. I have a fairly unrestrictive 2.5" exhaust and 3" TID.

damn thanks for the good info guys. ok i'll do it right and port my wastegate. but just incase. would a S5 Turbo flow better? if i used the stock s4 mani?

you cant bolt an s5 turbo on a s4 manifold, different shape/pattern.