3inch exhaust w/ cat

[mitsuclipsegsx]

i have a 98 GSX and soon i will be buying the HKS carbon ti exhaust & DP, now my question is what should i do w/ my cat, i was thniken of buying a DP that goes through the cat(but heard it makes o2 sensor go bad), or maybe a test pipe but i heard then u'll get shit on ur bumper, but my car is black??? and also i have an a/t so is a 3inch to much, i dont want to lose lower end, what would be best for me, but i deff want the hks exhaust?
thanks

 

[99GSTszeikus]

i got a 3 inch apexi exhaust with a cat eliminator, and yea it gets shit on my car, but when i wash it every other day it doesn't really matter that much. mines also automatic and i really didn't notice too much of a loss in low end. Personally i would just get rid of the cat because from what i hear it would help alot more then getting a hi flow cat. just my opinion. Also my 02 sensor is fine.

 

[98RedGs]

Less backpressure in a turbo setup the better.
Eliminate the cat if you don't have emissions.

3inch if your gonna do some good modding on the car.
2.5inch if your going to do a few bolt-on's and not heavily modify the car.

You will be fine with either/or whichever you choose.

 

[mitsuclipsegsx]

any other 2g people have a their cat elimatdated and their o2 sensor is fine

 

[mitsuclipsegsx]

about what 98RedGs said about less backprssure is better for turbo so does that mean 3inch is better or 2.5???? and i plan i getting exhaust this summer and next sumer big16 turbo/injectors,fuel pump,FMIC so is it worth getting 2.5 or 3ich??
thanks

 

[98RedGs]

If your changing turbos and other items like that then go 3inch.
Check this out.


http://www.dsmtuners.com/forums/showthread.php?t=36013&highlight=exhaust
Which catback exhaust? ^

http://www.dsmtuners.com/forums/showthread.php?t=12986&highlight=3inch+exhaust
http://www.dsmtuners.com/forums/showthread.php?t=77847&highlight=exhaust
http://www.dsmtuners.com/forums/showthread.php?t=56597&highlight=exhaust
http://www.dsmtuners.com/forums/showthread.php?t=3147&highlight=exhaust

Those should help you decide 2.5 or 3.

 

[Syndicate13]

I don't understand how people can say they lost low-end performance with their exhuast. Mine improved a lot. Think about it, the turbo spools faster and easier so that, to me, would indicate an increase in low-end pull.

 

[98RedGs]

I don't understand how people can say they lost low-end performance with their exhuast. Mine improved a lot. Think about it, the turbo spools faster and easier so that, to me, would indicate an increase in low-end pull.

Because you have no backpressure down low anymore.
That's how it's been explained to me.
http://www.dsmtuners.com/forums/search.php?searchid=64652

 

[L2RTSiAWD]

As long as the mufler is places so the tip sticks out of a the bumper a little bit you won't get anything on the bumper.

My car is blowing oil since the turbo seals are gone and I have nothing on my bumper.

 

[mitsuclipsegsx]

so when i get my 3inch downpipe no cat and hks carbon ti, i wont have boost creep w/ my stock t25,intake,gredy BOV ic pipes
thanks

 

[DSMNightmare]

Hey, here is what I ran with my A/T FWD when I raced it.

1. 2.5" downpipe. Unless your going BIG your going to want to keep the downpipe size smaller to prevent low end torque loss. This was advice given to me by Russ Coxe and/or Kiggly(can't remember which) who are the fastest A/T people on here.

2. Test pipe. You can go with the cat and the O2 sensor will be fine but honestly your not hurting anything if you use a test pipe. The rear O2 sensor does not adjust the fuel, only the front O2 sensor does that. You will notice the gains if you use a test pipe.

3. I had 3" tenabe racing medallion on the car(with test pipe) and never noticed any carbon deposits on the rear bumper.

Bigger is not always better especially when your running the stock T25. You should not see boost creep from that setup but there are no guarantees. Word of advice though. Spend money on beefing the tranny up. They are cheap to beef up but really expensive if you burn up an A/T. I ran 13.8@15psi on pump gas at 101.3mph with that FWD A/T setup. You should be able to do much better if you get the right turbo on an A/T AWD.

Good luck,

 

[mitsuclipsegsx]

hey thanks for the info it really helped, yeah i was thinken of getten a 2.5 but down the road maybe 1 year, year&a half i want to upgrade to a big 16g,injectors,fuel pump, and FMIC, and wont a2.5 be to small??? or maybe i should get 2.5 now then 1 year + i wll get a3inch would that be a good idea,, and u were sayen spend money on the tranny what can i do to my a/t??
thanks

 

[DSMNightmare]

hey thanks for the info it really helped, yeah i was thinken of getten a 2.5 but down the road maybe 1 year, year&a half i want to upgrade to a big 16g,injectors,fuel pump, and FMIC, and wont a2.5 be to small??? or maybe i should get 2.5 now then 1 year + i wll get a3inch would that be a good idea,, and u were sayen spend money on the tranny what can i do to my a/t??
thanks

You wont outflow the 2.5" downpipe with a 16G. I had a 20G on my 2.5" downpipe. Do the downpipe before the turbo. That way you'll have noticable gains now. Downpipes are cheap turbos and FMICs are not. As far as the A/T you can do several things but the most important things are:

1. End Clutches: Very easy to replace. There is a vfaq for this.
2. Shift Kit: This will help with shifting and help save your tranny. There is a vfaq for this too.
3. A decent Stall converter: This option is more expensive and mor difficult to do but it does help as well.

If money is no option you can go Level10 A/T. That is the high end tranny for A/Ts. I had a level 10 on my FWD but I also got a major deal on it. If you buy it from Level10 you will spend around 2500-3000 bucks.

 

[mitsuclipsegsx]

why do u have a 2.5 DP over a 3inch DP??