Cats or no cats

[Juiced46]

Ok maybe i should have explained. James @ RWTD did my tunes. Car made the 449 with the stock cat pipe and 23 degrees of timing with the regular pulley tune. He then sent me 2 other tunes to try with my new H pipe. Identical A/Fs. He called one of them "agressive" which had 22 degrees. The other file had 21 degrees. Both of the 21 and 22 degree tunes put down identical #s, and both backed it up with another pul that made 1-2hp less.

So to sum it up, there was actually timing pulled out of the tune with the new H pipe. The gain was from the swap for sure and not the tuning. A/Fs were identical.

Dave

 

[Juiced46]

Also mods on the car for those who are curious @ the time were

Stock unported eaton. 2.93 pulley. 100 mm idler, MRT H pipe, magnaflow catback, AFM CAI, and a Predator

 

[trey193]

No cats here!

 

[95_XB331]

Granted I do not own an 03/4, but I just went through this with my 95 as my magnaflow cat-pipe clogged and I went to a custom catted flowtech setup--I ran a basic flowtech O/R H for 2 weeks. Loud as heck, did lose some low-end under 3000rpms, but above 3000rpms under WOT was pretty incredible, nascar loud with the power, it just kept pulling hard (turbo like?), no traction period on radials. It would be great for the OT/strip/dyno I concluded.

I fitted smaller than stock magnaflow universal cats on the O/R pipe (i.e. can be disconnected ) and power delivery reversed!! I picked up boat load of lowend TQ and power is pretty linear in the higher revs, not as good as the O/R, but more responsive. The 95's a street car and the O/R was way too loud, so I'm keeping the cats on for now.

 

[ygohome]

i gained over 20 rwhp and about 10 rwtq after removing the cats on my bassani xpipe.

 

[dgussin1]

Originally posted by ygohome
i gained over 20 rwhp and about 10 rwtq after removing the cats on my bassani xpipe.

what are your other mods?

 

[ygohome]

my mods are pretty sparse...

2.93 pulley & 74" belt
bassani cat back & xpipe
ngk-tr6
9" afe filter
diablo delta chip with 91 oct & 100+ oct programs (from amazon)
17x10.5 w/ 315/35/17 nitto DRs

 

[InArmyWPride]

i have bass.. with x pipe and cat back i got great performance and sound i have a buddy that did x pipe and no cats and it sounds soooooooo bad!! i hate how it sounds, sounds like crap!! So keep cats!

 

[Davesnake]

Originally posted by InArmyWPride
i have bass.. with x pipe and cat back i got great performance and sound i have a buddy that did x pipe and no cats and it sounds soooooooo bad!! i hate how it sounds, sounds like crap!! So keep cats!

IMO x-pipes sound like crap period.... I'm ready to sell mine.

Dave

 

[roided03]

hey i just installed bassani x pipe with cats and their mid-lenght headers. Good thing when i dynoed the car i saw increase in trq and hp throughout the entire rpm range. NOw for the not so good part i feel like the car pulled harder when i had just my cat back, 2.76, chip, intake? how could this be possible, i see the difference on dyno sheet but dont feel the difference on the road idkkk

 

[Juiced46]

roided03 can you post your dyno sheet? and where did you dyno the car?

 

[BigBeez03]

IMO - I think a certain amount of backpressure is necessary to keep TQ strong, so some may notice a loss by removing cats. Contrary to what many think, in a new car with low mileage, the cats are not really inhibiting exhaust flow. They don't have enough mileage/use yet to get clogged and impede the exhaust. I actually noticed a loss in low end grunt when I installed my Magna CB. Sound was worth it but was not prepared for loss of TQ. I heard a wise mechanic once say, "any mod that improves performance comes at a cost, it will affect the car in a neg way to some capacity, no gain comes without a loss somewhere else".

 

[Juiced46]

Only negative affect my H pipe gave me was the wear on my tires

i totally understand what you are saying. I however didnt loose any downlow at all. i picked up power everywhere.

 

[roided03]

hey juiced im not sure how to get my dyno up on the site however, like i said i picked up trq &hp thorugh out the whole entire rpm range only thing that changed was my a/f became more conservative on the top end went from 11.8 to 11.ish, like i said idk maybe i was expecting alot more from the car, i was told by cody mac that i would see a HUGE difference once the headers were on, and i guess thats what i was lookin for. BUt correct me if im wrong, the car shouldnt pull less hard with the mods if the dyno pulls reak more power then before right??

 

[Juiced46]

Well if the dyno is showing gains, you should definetely feel it.

But it can all be in your head as well. It may not feel as fast but it really is faster. Hell i have over 600rwhp, and it doesnt feel like it lol.

 

[roided03]

does your car generally have to be retuned after installin headers and x i didnt think it had to. I did not have my car tuned i just put it on the dyno see what it made. I had it dynoed over in port jeff Ny at power surge performance real good guy down there his name is sal manella. He looked at the the tune on the car and said it was good, plus he couldnt tune the car cause he didnt have a burner for the diablosport chip

 

[Juiced46]

if u could get me a graph of your a/f i can tell u how it looks.

[email protected] if you have a scan and want to email it to me. The headers can affect the tune

 

[roided03]

hey juiced i sent you my dyno at email

 

[E. Green Cobra]

cats- but hey if you feel its your priveledge to pollute something you don't own, feel free to throw your used oil in your local water supply- is a few horses really worth it?

 

[MG01SVT]

No flame intended Green cobra, but you are not exactly driving a Prius yourself there.
To chime in on the Cat or No Cat debate. When I had my 01 Cobra a good friend of mine(Toplesss) had the same car only a vert. Before I got rid of the cats, whenever we would race, he would always inch away on me up top. I replaced the factory H with a pro chamber and a day after that we raced again. 4 runs, all from a roll. I pulled him steadily each run and the car definitely ran stronger, but after a week or so of driving we raced again and once more dead even with him inching away from me up top. It is my opinion, that if you lose the cats you will gain HP for a period of time. I don't know if the gain is time based or mileage based, but once your computer learns this new alteration it compensates accordingly. I am now very suspect of dyno tests of catless mid-pipes that were thrown on and immediately dynoed. I think in order to be certain of your gains you should run it for a week or so and then dyno.

No expert here, just past experience

Aaron