rico05

As far as which would flow exhaust more freely, which is better? And is one REALLY that much better than the other?

rico05

bump

hurleyboi514

guttting the cats can actually hurt your flow. so dont be cheap and just got buy a midpipe! its worth the extra money!

rico05

Any other opnions?

Roy James

gutting your cats is fun, and it makes you think you are doing something and you are, about 2HP worth, . I know bc i did it to my 88GTU and it is faster, no doubt, but, my freinds with their mid pipes and "custom" muff shop straight pipes KILL ME just bc of that. hehe, have phun

von

The trick is to gain exaust velocity so it pulls the exaust out of the engine faster. So gutting the cat will create turbulence slowing down velocity.

SpeedRacer

Definently get a racepipe. I have the bonez racepipe, and had it on my car for 1 1/2 years. It gave great power gains for what it was, and sounded damn good. I just put on headers, and had to remove my racepipe. I had to gut my old cat, and put it in after the headers. Anyways, the shape of the cat isn't free flowing at all. There are metal ribs that go along the inside of the cat, and a metal rod that goes right through the middle of it, that used to bring in fresh air from the SAP. Also the gutted cat sounds like CRAP. VERY tinny, and buzzy. The other reason, is that a racepipe doesn't hang as low as your CAT. After putting in my racepipe, a year later I dropped the car 2" thanks to the GC coilover kit. I never had bottoming problems, until a few weeks ago after putting my old gutted cat on. Now I scrape even on fairly small speedbumps. It truly sucks.

supergoat

Gut them. That is until you can afford a down pipe. I have had mine gutted for a while and yes it does produce a gain. But it wont outflow a good downpipe. I plan on getting a RB downpipe sometime in the future.

Edit: The sound is NOT tinny at all on my car. ofcourse I also have a high flow CAT and stock cat-back, so that may have something to do with it.

von

How much of a difference with the heads and gutted cat than with the race pipe.. can u tell me.

SpeedRacer

He's asking about gutting ALL cats vs. a Racepipe, not just the precats, in place of downpipe. The reason your car doesn't sound tinny, is cause you still have a cat.

supergoat

My bad.

SaabGuy

Would I ever run into a problem of overboosting with both my cats gutted? what boost pressure can I expect with one or both cats gutted??

von

So was thier a difference with the header compared to the race pipe... as in noticible difference.. didi u lose any low end

rico05

Well, I am buying von's old racepipe anyway, so I guess my questions are over!!!!!

SpeedRacer

How much difference with gutted cats vs. racepipe? I couldn't say exactly, but enough that will you notice the difference in power. Probably just 1-3HP. But a racepipe will sound SOO much better, than a gutted cat, cause the racepipe comes with a presilencer. The presilencer doesn't restrict airflow and doesn't even really make your exhaust more quiet. It just gives a better deeper tone, rather than the chainsaw on crack sound, my car now has with gutted cat on. I am planning on having my racepipe cut, and a flange welded on, so I can use it in place of my cat. The headers didn't hurt my low end at all. It helped my midrange and high-end a lot though. I can easily pull past 8000rpms without power dropping off now.