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Discussion Starter #1
Just wondering...., Im looking at different downpipes, most dont have cats, but what about the ones with intergrated, high flow cats? Obviously they dont flow like the catless ones do, but does anyone know what the difference is? I know alot of people run around 16psi with a DP, any less with the intergrated cat DP?
Thanks
John
 
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Discussion Starter #2
When I bought my car it had a high-flow cat hooked to my RMM downpipe. It worked pretty good. I eventually replaced it with a new RMM downpipe with no cat. It made a slightly noticeable difference in performance and it sounded quite a bit better. It was a lot more thoaty at WOT. I don't remember any significant difference in boost levels. I think my max boost went up a bit in 4th gear and up, but it was already going to 20psi anyway. I think my turbos spooled just a hair faster as well. Overall though, the high flow cat worked great.
 

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Directed Engineering said:
When I bought my car it had a high-flow cat hooked to my RMM downpipe. It worked pretty good. I eventually replaced it with a new RMM downpipe with no cat. It made a slightly noticeable difference in performance and it sounded quite a bit better. It was a lot more thoaty at WOT. I don't remember any significant difference in boost levels. I think my max boost went up a bit in 4th gear and up, but it was already going to 20psi anyway. I think my turbos spooled just a hair faster as well. Overall though, the high flow cat worked great.
Any idea if that high flow cat would pass California smog tests?
 
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Discussion Starter #4
Guido said:


Any idea if that high flow cat would pass California smog tests?
Apparently, the places that sell the DP with the intergrated hogh flow cats says that they will pass sniffer test, but may not pass visual since they are in the DP and are not visual from the outside.

Thanks Directed, thats what i was looking for, im trying to keep a cat on the car, but id love to have the few extra horses and the better sound...., so its still a toss up for now
Later
John
 

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what do u guys think about random cat
are they flow good as rmm dp
I am thinking about gettting just the 2nd cat random downpipe
$369.00
with my t78
right now , I have 2nd stock cat on my supra single turbo
no smell at least little bit laggy though and very quiet :) compare to my straight rmm



ken
 
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Discussion Starter #6
Back in the day when I was running a bleeder-T, I was hitting around 17-18psi with the Random Tech D/P w/ Cat. I had to gut the cat after high-centering it :eek: , and after doing this, my boost was shooting over 20psi with the bleeder-T. Now with the AVC-R it's fine, but the cat was definately creating atleast some noticable back pressure.

BTW, My best trap speed with the Cat at straight-BPU was 117.43, without the cat it jumped to 118.99. Not a huge difference, but still a difference.

Mike T
 

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I passed emissions VERY easily with the hi-flo cat. But compared to straight DP cars you will probably lose 10-15 RWHP, not to mention the cool throaty exhaust sound. :( I hear the newest Random Technology hi-flo is the best one so far.
 
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Discussion Starter #8
intresting, so as C5 killer said you can have a high flow cat either welded or just put on a single turbo kit is that correct? And if so can i have the RT high flow one put on ?

Basically my question is can i have a high flow cat put on the down pipe if I go single?
 

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Yes, you can. I am installing a DE kit, and the RT hiflow bolts right up. If you are using a mainstream kit, like a RPS, SP, Greddy, you will have to cut a pipe, and weld a cat in. As for power, I did a back to back dyno on a 97TT BPU+, we got +/-374rwhp with the cat, and 401 with aRMM DP. This was on 91 octane, with an AFC. I am not sure I would want my daily driver to be louder than it is in TTC, with the RT DP, sounds like a Saleen on steroids(not sure if that's good, but it does sound very nice). I think it will be quite a bit louder with an open wstegate, and a single VS two turbos). I easils pass the sniffer test in NorCal, but you won't pass a visual due to only one cat. Carl Byck
 

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Guido said:


Any idea if that high flow cat would pass California smog tests?
Yes you can. I just passed at a smog test only station with the new Random Tech. cat. It comes with a CARB number so it is exempt. I am pretty sure other hi-flow cats do not come with a CARB exempt number.
 
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