JEB99TA

iTrader: (32)

I've done SO much and gained so little. My JBA shorties give me a little more than the restrictive factory headers ('98-'99) and they have a 3" collector. The inlet pipe for my CAT's is only 2 1/2". This restriction is killing me. For the short term, can this be overcome by ordering and installing 3" aftermarket pipe sections? Two questions:

1. Anyone know of a company that might make right and left side 3" pipe sections that would replace these Random Technology catalytic converter pipe sections? I can't buy LT's right now.

2. My rear O2 sensors are turned off right now via my dyno tune ... would I need to buy dummy 02 sensor simms for the front and would my PCM see them as they see them now? I need the PCM to continue to function nromally as they are now and still adjust A/F and TRIM's at higher speeds/rpm's when the engine/temperatures require it.

hourang

iTrader: (6)

an exhaust shop can make you some 3" sections for fairly cheap. you cannot remove the front o2s, that is how the computer adjusts your a/f ratio.

GuitsBoy

iTrader: (4)

like hourang said, try an exhaust shop. Otherwise check the sponsors or summit / jegs for a collector reducer that will go from your 3" 3 bolt (flanged) to 2 1/2". Also, under no circumstances should you put o2 sims on the fronts. Your ECM will have no idea what it's doing. Even people doing MAFless and speed density tunes still keep their o2s.
-T

ddelallata

iTrader: (2)

What are you complaining about? Take all that restrictive **** off! You live in Florida and can get away with anything down there as there is no annual vehicle inspection requirement. We envy you.

HOSS99

Check LS1 Speed (sponsor----->) They have 3" offroad pipes to replace the RT CATS that came with SLP LT's.

slik98z

this can be over come by removing those cats and running without them *****

i dont think the 2.5 inch cats are your issue. shorties aren't gonna let you gain anything more than what the primaries can push out. Seems kinda dumb to me they even put a 3 inch collector on them in the first place.

so grow a set, take out the cats and enjoy the new found sound and power...but still, its the headers causing the restriction, not the collectors to cats

good luck man
T

jrp

iTrader: (16)

dont feel bad JEB, local guy here is running heads, tr224 and bolt ons and shorties and is only putting down 357/348, with his hotcam and slp LT's and bolt ons he only put down 369rwhp. tuned on both accounts. oh ya, m6 and 10 bolt.

JEB99TA

iTrader: (32)

JRP ... you always make me feel better ... hahaha!!!! I've spent all I can spend right now. Too bad I didn't know what I know now. LT's will go on later down the road, then, LS6 intake. That dude you're referring to must really be disappointed .... all that and only 369 RWHP ... ****!

Anyone else care to comment on my initial post?

GuitsBoy

iTrader: (4)

Seriously, i dont think your cats or the 2.5" piping is really killing you here. Sure Long Tubes would have helped you much more than shorties, but it looks like youre gonna be stuck with the shorties for a while. What exhaust are you running? You cant expect shorties to flow better if youre still using a stock muffler.

-T

JEB99TA

iTrader: (32)

I'm running the adjustable Borla exhaust with a Q-tech cutout, so, there's no restriction there. I ran it open on my dyno pulls. Everything's 3"

The 2 1/2" section can't help much. The 1 5/8" primary tubes are the only other source I can see restricting me.

blkZ28spt

I think it's mostly the shorties holding you back Shorties are **** for horsepower. Even 1 3/4" primaried shorties, doesn't matter. I know that you didn't know when you modded what you did, now (sucks ) but shorties to a Borla with a Q-tech plate is a pretty expensive yet low horsepower choice. See what happens when you ditch the cats and add longtubes

If I were you, i'd look into what it would cost to start all over. Sell the shorties and put the money towards pacesetters. If you really had to, you could always sell the borla for another system and gain money as well. Just a thought

Dope

iTrader: (2)

Anyway, can I ask why you bothered with shorties in the first place? You're looking in the wrong place for your restriction. If you want to restrict flow, keep your stock manifolds. If you want to gain power, get at least Macs, preferrably LTs. If you want to throw away money, get shorties.

If you're really on a super budget, just get an exhaust shop to hack off your cats and run 3" to 2.5" reducers. You'll gain a handful of HP along the way.

Dope

Dope

iTrader: (2)

Oh, and just for reference, my old A4 car (before I sold it) had the same mods as you, except for no cam. 325rwhp/335rwtq with no tuning at all (leaning out and picking up KR on the dyno). Oh yeah, did I mention I had FLP LTs with cats?

See what I mean? With that cam and LTs you should be around 365-375rwhp at least.

Dope

JEB99TA

iTrader: (32)

Thanks for all your comments and advice. When I put shorties on last year, lowend torque and emissions was my concern. Now, my goals have changed and Long Tubes have been decided on. I guess to do it right, I just need to 'start over' as was said.

Tiger2o69

iTrader: (16)

I would try and add something but i think everythink has been covered. Sorry you gatta shell out all that money again for new headers. Good luck tho.

JEB99TA

iTrader: (32)

What year model was it?

WILWAXU

iTrader: (6)

All sins are forgiven.. back to tech..

Dope

iTrader: (2)

2000 Camaro

Dope