Who here is running their FI system with cats? My Z is getting the APS TT system installed within the next month or so and I was wonderinging how much power I am going to lose by running cats instead of TP's.

I currently have UTR's 200 cell metal substrate cats on my car which, I believe, is one of the best flowing cats made for the Z. In any case I am going to leave them on, I was just wondering how much power I will sacrific for the sake of keeping it legal.

 

Well power is one thing but throttle response and spool up is another. If you have the cats on when you get your car back and then take them off, the difference is crazy. So unless you want to be spoiled keep them on. Otherwise once you take them off they'll probably never go back on.

 

I would love to hear the impressions of anyone who has made the switch.

Thank you.

 

you will probably melt them. I wouldn't run them

 

I thought that all the twin turbo systems (according to the companies) are designed to run with stock exhaust including cats...

There are also lots of OEM turboed cars running on cats with the same type of element that I have... like the Veyron. If 1000hp of exhaust thermal energy doesn't melt them, I doubt that a little 400whp car is going the melt them anything soon.

Is there something I am missing?

 

I think what you are missing is that the Bugatti Veyron is a 1,000,000$ car, so the materials may just a little bit higher of a quality as opposed to the Z (for that window sticker one would hope so...) For all that we know the Veyron's cat may cost more then the whole Z car.

What I am really curious about is how do the test pipe compare to high-flow cats?

 

Maybe, but you would have to agree that alot of the aftermarket parts that we put in our cars are as good as or better than any OEM part in the world... The cats I have are made of polished 304SS, have 2.5" pipes and a 200 cell/inch metal substrate core. It doesn't get much better than that. Also, from what I have been told, there are only one or two makers of metal cat elements in the world so it seems real likely that the same companies that are OEMs for ferrari, bmw, lamo, and all the other companies in the world that spec metal cats, also made the ones in my car. In all honesty, I have absolutely no concerns about my cats melting, I just replied to Zibman to prove a point.

The problem with my cats is not the flow (I have been told that they flow better than many HF mufflers), but the placement of the restriction (i.e., close to the turbo) that creates spool issues and I have known from the beginning that this would rob some power and responsivness. My real point in this thread is putting numbers on that power loss.

 

You know, we are both in the same boat b/c I would like to keep my car as clean as possible w/out sacrificing any spooling speen when I go TT in spring. After reading your reply I see that you know about cats much more then I do, so I apologize for the sarcasm. So if you find anything in your search, can you please post in this thread?
BTW, do you have aftermarket cats now? If you do which ones?

 

Yes, I am currently running UTR's cats... see attached. I wanted Helix, but they stopped making them.

 

Why risk it? I promise you, the potential of them melting is there. Not saying 100% that it will happen, just doesn't seem worth it to find out. What's the big deal about running test pipes? Especially if you have gone as far as putting a twin turbo kit on your car? if you are concerned about emissions testing, just swap out the test pipes come testing time and cross your fingers about the rest of the kit.

Why ask the forum if all you are going to do is argue about it and will be doing it anyways? Just run it and let us all know what happens.

Yes, you will be giving up a significant amount of performance by running cats. How much depends on other things like the rest of the exhaust and tune.

For what it's worth, those cats probably weren't R&D'd on a TT setup and most HFC I know say "not for use with FI".

 

WRT
"It doesn't get much better than that. "

Actually it "can" get a better than that. You can fab a 3" set of houseing back TPs with 3" metal matrix cats (ie. from vibrant racing) welded into the rear section.

http://www.vibrantperformance.com/vi...rformance.html

This type of setup will flow better than your current 2.5" setup. For example the new APS 3.5" TPS could be modified to accept the linked 3" metal cats. Not as well as a pure TPs , but better than a 2.5" arrangement.

 

Hmmm... You have me thinking.

True, you can always get bigger on the pipes. Thanks for the link. The great part is, from the looks of those cores, they can be cut to accept any size pipe. I just wonder what SS grade they use (for heat resistance). Maybe I will give them a call.

 

I know it seems dumb to want to run cats, but I do want to keep my car street legal and I hate the way a car with TP's smells like a gas station driving down the street (especially with how rich stock APS maps run the A/F). I also like a car that is fairly quiet which is difficult with TP's

I'm not trying to argue, I just don't see heat as a big problem with metal cats (unlike ceramic cores which make like popcorm if you hit their flash point). I may end up doing both and seeing if the difference is bearable. If I'm feeling real ambitious, maybe I'll get both dynoed and put some numbers on it... I just was hoping someone had done that already.

 

I'm running the APS TT with Ultimate Racing Cats and have been very happy so far.
I also do not want to contribute any more waste to the envionment than I have to.

I am however considering running TP's because I believe I kinda maxed on my power band at this point. Once my car is fixed (see seperate thread) I am going to get my tuning done and if I can't hit my goal then I'm getting TP's

 

I would love to see any dyno charts you have! I'm real curious to see how it effects the tq. curve.

Thanks.

 

here's my original dyno after the initial install/tuning

 

Just to confrim; that's torque and power at the crank (engine) like it says or at the wheels

 

on a dynojet it would have been 430 (13% on top of the dynamic dyno) at the Wheels. This is neither crank nor wheels....it's a bit complicated they way they do their outputs and there have been quite a few discussions that I'm not going into again.

 

Fair play. Its all about comparisons on the same dyno before and after mods; that's what counts, 'absolute numbers' are never absolute

Edit -> Just saw the other thread hope you get it sorted soon

 

ht4 if all you want is real numbers here they are. Aps TT with stillen exhaust, kinetix h/f cats I removed these and put in test pipes and gained 37 rwhp / 20 rwtq and the resonse was nite and day. I hope this helps you out.