so i just put a cut-out on my car,we routed it straight off the turbo and goes down to the side,i was tuned for a 2 1/4 xhaust,do i have to re-tune my car for the cut-out,since its a big difference??????and is there any tricks i can do with the tuninig,because i ran the cutout straight off the turbo so theres no o2 bung to plug a wideband.......

 

should have ran the cut out further down to give room for the bungs, it might affect drivability now since there is no O2 reading. the cut out on a friends car did not change the reading too much maybe .2-.3 AFR points. It went from like 10.8 -11.2 through out the power band.
Get an AFR meeter like PLX 300 or UEGO. This will give you an accurate reading and a baseline.

 

ya,i was goin to but i my i have 3 inch downpipe and then it bottlenecks to a cat then to a 21/4 xhaust

 

don't you just need one o2 bung before the cutout for wideband tuning? i'm sure you can just get one welded on. how far is your cutout from the turbo? 10-12inches?

 

its about 10 inchs straight

 

get a pic for us

 

retune.

 

so you think it will make that big of a difference?????

 

so you think it will honestly make that big of a difference???

 

You need to get your O2 inbetween the cutout and the turbo, that's for sure. And yeah, I'd definitely retune.

 

yea, id retune. i have mine tuned at a lil less than 12:1 with my cutout open and with it closed (stock exhaust) im just about 11:1, so it varies up to about a full a/f point. with the cutout open im making a solid 30+more hp than with it closed, and consequently you will need more fuel to compensate

 

i have the same setup with the cutout straight off the turbo and no bung for the o2. i haven't gotten my car tuned yet, will this make things more difficult to tune?

p.s. im not tryna jack the thread, i figured we're both in the same situation.

 

no,completly understanable,i need some answers,hehehe j/k,but how much boost you think i can run with it open i used to run around 17psi

 

well with it open, everything elsse being the same you should make a few more psi right out of the box, just due to better flow

 

of course you need a retune. i bet your turbo is gonna spool wayyyyy faster. you want to go lean?

 

Tuning before and after having your cutout open may affect the tune.

Depends on many variables.

I have a 3" exhuast w/a cutout and w/it open it changes my a/fs from 10.9 to 11.4 in boost.

IF you have a stock exhuast and a cutout and are tuned with a stock or somewhat restrictive exhuast, the cutout will dramaticlly make a difference.

Always variables...depends on your application.

 

do think that 14 psi would be safe!!!!

 

with 5 psi u will be super safe

lol, jk..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FONK &raquo;</TD></TR><TR><TD CLASS="quote">do think that 14 psi would be safe!!!!</TD></TR></TABLE>
I can tell you this far sure. Tuning it would be safer.

 

I've just taken my exhaust off from the downpipe back. From a kteller/magnaflow 3" to just open 3" dp.

It may have changed my a/f by 2 tenths consistently....spool is much quicker though, was able to gain 4-5 psi (9-14psi) at 5000rpm....and a/f stayed where it was supposed to.