Hollowing a high flow cat

[4gfun]

I have a Catco high flow cat but in consideration of my Boost Fade problems and a suggestion that the Cat may be too restrictive, I am considering hollowing it. It looks like hollowing it used to be the thing to do a few years ago, but now it is established that it is not the way to go.

That seems to apply to a stock cat though. What would happen if I hollowed an already high flow cat? Times are tight. I have time not money. I just want to see if it helps my problem and could always do something else later if need be.

Any ideas?

Thanks!

 

[sax_man]

Just buy a test pipe. They are like 30 bucks on ebay. And then sell the high flow and make some money.

 

[pboglio]

I have a Catco high flow cat but in consideration of my Boost Fade problems and a suggestion that the Cat may be too restrictive, I am considering hollowing it. It looks like hollowing it used to be the thing to do a few years ago, but now it is established that it is not the way to go.

That seems to apply to a stock cat though. What would happen if I hollowed an already high flow cat? Times are tight. I have time not money. I just want to see if it helps my problem and could always do something else later if need be.

Any ideas?

Thanks!

Drop the cat, run open and you will find your problem. I did it one day and it wasn't too bad. Hollowing might be fine, but straight pipe is much much better.
I've got a straight pipe laying around here that uses flanges for a 2.5" system.

 

[4gfun]

Thanks for the ideas...VERY good ideas indeed!

I won't be out of a dime with your brains!

Pboglio? Do you really think that the cat is responsible for my Boost Fade problem? Did you really mean it that way?

As a refresher, this is the problem:

http://www.dsmtuners.com/forums/newbie-forum/382481-boost-fade-falling-dropping-problem.html

You said that way back here didn't you concerning a similar issue:

http://www.dsmtuners.com/forums/newbie-forum/377516-wont-build-more-than-18-psi-my-big-16g.html

 

[pboglio]

High flow cats are restrictive in general. Gutting one is nowhere equal to a testpipe due to the large expansion/contraction and resulting flow losses. I agree an e-bay testpipe is the way to go.

I haven't personally tried the new metal matrix round style which are supposed to be better. A 2.5" or 3" high flow cat flow about equal, since the catalytic converter core size, and depth are similar. It'll cost you a good 2-3 psi on the topend if your gunning for maximum power. Personally, the difference cat vs. no cat at big boost is big. The sound difference on my car is minimal, hence I don't run one.

 

[TSimage]

Sell your cat, make a couple bucks on it.. Then replace it with a test pipe.

They are restrictive but not by much. A proper flowing 3" cat isn't going to lose much power to a straight pipe, period. But I suppose every little bit helps.

 

[4gfun]

Got what you are saying guys...but can the cat cause boost fade?

http://www.dsmtuners.com/forums/newbie-forum/382481-boost-fade-falling-dropping-problem.html

 

[pboglio]

On a 400 w.h.p. car, a highflow cat is going to be very restrictive. It was mildy restrictive at 300 w.h.p. and actually not too bad if you didn't mind lag.

 

[sax_man]

Heck even when I was running the t25, there was a noticable difference in spool time gong from the cat to a test pipe. It was nice for autox let me tell you

 

[4gfun]

Well I dropped the cat and it isn't my problem......thanks for your wisdom on the cat!

 

[TSimage]

Well I dropped the cat and it isn't my problem......thanks for your wisdom on the cat!

Or lack there of ...

I ran a Buschur HighFlow 3" cat and didn't have much improvement switching to the testpipe. And this was on my V-trim and 35r setups.

 

[4gfun]

Lol, no actually you encouraged me to rule that out instead of sitting on my behind. Good info on the cat's capacity.

Or lack there of ...

I ran a Buschur HighFlow 3" cat and didn't have much improvement switching to the testpipe. And this was on my V-trim and 35r setups.

 

[psx]

yea sell ## cat or trade with sombody 4 stock
why destroy it?

 

[4gfun]

I am just going to keep it...not the cause of my problem.

yea sell ## cat or trade with sombody 4 stock
why destroy it?