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Does A Full Exhaust = Boost Creep?

colourclassic

By colourclassic,
in Engines & Forced Induction

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colourclassic Mentor

colourclassic

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Posted

Hey guys,

Looking at getting my car tuned in a few weeks, and have been doing all the supporting mods in advance. It is a stock S2 R33 Gts-t. So far i've done:

K&N Panel filter

R34 SMIC

JJR Bellmouth dump

Apexi N1 4" cat-back

Stock boost

I'm currently looking at upgrading the crappy compliance cat to a high flow 100cpi item (no dodgy de-cat) and am worried that it might free up the exhaust too much and lead to boost creep. It is the only stock part left in the system and it does not currently creep at all.

I'm only looking at a basic tune for a few extra kw's at this point, and don't want to have to port the wastegate or anything like that.

So my question, should I upgrade the shi**y old cat, or will it pose problems?

Cheers!

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colourclassic Mentor

colourclassic

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It won't "creep". It will definitely increase from stock though. Where it should max at 7 or so stock, you might get peak boost at more like 10 with a really free flowing exhaust. On an R33 that can suck because it can put you into R&R.

So assuming it doesn't go into R&R I should be okay? I was concerned about it creeping up to 12+ psi with a full TBE. I'm guessing R&R feels somewhat like hitting limiter (albeit at lower revs)?

simpletool Mentor

simpletool

Posted
Posted

I doubt you'll even see 10psi with stock boost control (and the free boost mod).

That is a nice street setup and will need a tune to get the best from. Expect 180rwkw.

Still, Nistune might be better. Depends if you have any future plans at all ?! 90% of people do, but 85% of stats are made up 110% of the time.

colourclassic Mentor

colourclassic

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Posted (edited)

I doubt you'll even see 10psi with stock boost control (and the free boost mod).

That is a nice street setup and will need a tune to get the best from. Expect 180rwkw.

Still, Nistune might be better. Depends if you have any future plans at all ?! 90% of people do, but 85% of stats are made up 110% of the time.

Cheers mate, my biggest concern was AFR's getting too high and hitting R&R, as well as wastegate creep/boost spike.

I bought and installed a Venom 400 Series 100cpsi cat and took it for a drive this morning. Ambient temps were around 16 degrees and I did a few 3rd gear pulls to load the engine up and it didn't have any trace of flat spots or ignition pull. Having said that, it didn't perform much differently to the old cat, maybe a slight increase in response, but that could just be placebo. Does sound a bit better though :)

So going by the fact that it drives fine with the new cat, I can drive it 'as-is' with no worries until I get a tune? I'm a uni student/work part time so it could realistically be months before I get the money for one. I just don't want to damage this engine in any way haha

Edited by colourclassic
colourclassic Mentor

colourclassic

Posted
  • Author
Posted

So going by the fact that it drives fine with the new cat, I can drive it 'as-is' with no worries until I get a tune? I'm a uni student/work part time so it could realistically be months before I get the money for one. I just don't want to damage this engine in any way haha

Anyone? :)

Got a Pulsar Grand Master

Got a Pulsar

Posted
Posted

I recently got a JJR Bellmouth and have been using an R32 10psi actuator for some time.

with the stock Dump going to a 3" frontpipe to a 3" Catco Cat into a 3" Blitz Nur spec Catback, I got 10 psi.

with the Bellmouth replacing the stock dump and frontpipe, I get 10psi.

Being that I installed an SAFC 2 and got it tuned, my car was on a Dyno for the first time.
Boost actually drops off to around 9psi in the higher revs.

It's going back next week to fix a timing issue and retune but currently I have 181.8rwkw.

Clean your Airflow Meter with CRC MAF Cleaner, drive it and enjoy. :)

Series 2 R33. (Stock Turbo, Apexi pod, Metal Intake, ARC SMIC, 10psi, Bosch 044 pump, 3" turbo back exhaust, Apexi SAFC 2.)

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