legacycentral bbs

I have been doing a lot of research about downpipes recently, and have decided that i am going to go catless downpipe (most likely bellmouth) to an electric cutout (http://www.quicktimeperformance.com/QTEC/index.php) so I can really roar when I want to but be quiet when the cops are around. While telling my friend about this, however, he brought up the fact that this might cause me to detonate. He said "when you increase exhaust flow.. you're trying to compress more air because your turbo is going to spool faster... when thath appens your intake temps increase which will heat up your combustion chamber more which MAY cause detonation". I was wondering if this could be the case? and should I go ic at the same time as I go dp?

I dont think ONLY adding a downpipe is going to cause problems with detonation. If you have the funds for an i/c, its ALWAYS a good investment.

Also, all an i/c does, is make the charge cooler so more air can fit inside the combustion chamber. Hence, its real application is so you can run MORE boost without detonating.

If you dont alter your boost settings, but run an i/c, you may see your boost level drop a little. It will help prevent detonation though because of the cooler charge and the boost drop.

That is complete bullshit...


A downpipe won't make your SS start to detonate...

awesome guys thanks! In all the research I had done I read nothing about this and using my judgement I didn't think it made sence BUT...this being my first car I thought I would just double check with you guys.

P.S. a wrx downpipe will fit right? just kidding! I have searched through about a bagillion threads so I know it will fit but will be a little long. I am really looking forward to the sound of an exaust with a 3" catless dp and the cutout right after the dp >:)

Your friend doesn't know what he's talking about.

Detonation would happen if you were running higher boost, but that's not what you're doing.

More exhaust would cause your turbo to spool up to the correct speed SOONER, but then it's going to stop there and go the correct speed and no faster. There's this thing called the boost controller which is there to control the boost. It will take any extra exhaust and route it out the wastegate so that your turbo doesn't go too fast.