quiet exhaust and high flow?
02-10-04, 08:27 PM
#26
paximus:
I have the same exhaust on my single turbo, I like it a lot (other than the huge tip like you) but at least it is oval shaped and not a canister. I can't see how the exhaust would be the restriction with a hi-flow cat in the equation, N-tech or not. I haven't searched but I know someone on this forum measured the backpressure with an N-tech cat @ 5lbs with 12psi boost on stock twins, I've read it more than once on a couple threads.
Matt
I have the same exhaust on my single turbo, I like it a lot (other than the huge tip like you) but at least it is oval shaped and not a canister. I can't see how the exhaust would be the restriction with a hi-flow cat in the equation, N-tech or not. I haven't searched but I know someone on this forum measured the backpressure with an N-tech cat @ 5lbs with 12psi boost on stock twins, I've read it more than once on a couple threads.
Matt
02-10-04, 08:32 PM
#27
Here it is:
https://www.rx7club.com/showthread.p...h+backpressure
And I quote from capt. bill1:
"I run a DP, a SS MP with a Borla straight thru muffler put in it and a PFS cat back(came with the car). Sounds great and is not too loud.
I had a N-Tech high flow (what a joke) cat. With the N-Tech cat I had 7lb of back pressure. With the Borla, 2lb. Don't waste you money on a "high flow" cat unless the company can give you real world back pressure numbers."
https://www.rx7club.com/showthread.p...h+backpressure
And I quote from capt. bill1:
"I run a DP, a SS MP with a Borla straight thru muffler put in it and a PFS cat back(came with the car). Sounds great and is not too loud.
I had a N-Tech high flow (what a joke) cat. With the N-Tech cat I had 7lb of back pressure. With the Borla, 2lb. Don't waste you money on a "high flow" cat unless the company can give you real world back pressure numbers."
02-11-04, 07:08 PM
#28
i heard back from nick at n-tech, here's the email:
Well, I thank you for the question, because it caused me to go back and re-research the answer. I will have actual flow numbers for you at some point soon, but for the moment, it is safe to say that the cat flows at least 47% better than the stock one. If you looked into the pipe before installing it, you saw how the inside
is constructed. If you look into it again and it still looks the same, then the cat is fine. There is only a restrictive mesh in the pipe to get the exhaust to go through the catalyst. Unless the mesh has been clogged by debris or the interior of the cat has collapsed (which would
be visually obvious), the flow will not have changed. If the catalyst material clogged, the flow would remain unchanged, but the cat would no longer pass emissions.
I was originally informed that the cat itself flowed 96% of a straight pipe. Upon re-investigation, I was informed that to be a legal cat, with CARB certification, it could not flow more than 47% more than a stock converter. What I am now researching is WHICH stock converter, since we use this same converter for several applications, and more importantly, what the flow numbers are. I am fairly certain that the flow percentage
numbers are for a cat application that had higher HP numbers than the stock 3rd gen. Again, the important thing for you is to make certain that the cat is not physically blocked at this point. If not, then it is
not the cat.
I have changed the information on the web page until I can find our flow numbers. Once I retrieve them, I'll post it on the web page.
Nick Riefner
N-tech Engineering: Performance Parts for Performance Cars
www.ntechengineering.com
(863) 324-6692
Well, I thank you for the question, because it caused me to go back and re-research the answer. I will have actual flow numbers for you at some point soon, but for the moment, it is safe to say that the cat flows at least 47% better than the stock one. If you looked into the pipe before installing it, you saw how the inside
is constructed. If you look into it again and it still looks the same, then the cat is fine. There is only a restrictive mesh in the pipe to get the exhaust to go through the catalyst. Unless the mesh has been clogged by debris or the interior of the cat has collapsed (which would
be visually obvious), the flow will not have changed. If the catalyst material clogged, the flow would remain unchanged, but the cat would no longer pass emissions.
I was originally informed that the cat itself flowed 96% of a straight pipe. Upon re-investigation, I was informed that to be a legal cat, with CARB certification, it could not flow more than 47% more than a stock converter. What I am now researching is WHICH stock converter, since we use this same converter for several applications, and more importantly, what the flow numbers are. I am fairly certain that the flow percentage
numbers are for a cat application that had higher HP numbers than the stock 3rd gen. Again, the important thing for you is to make certain that the cat is not physically blocked at this point. If not, then it is
not the cat.
I have changed the information on the web page until I can find our flow numbers. Once I retrieve them, I'll post it on the web page.
Nick Riefner
N-tech Engineering: Performance Parts for Performance Cars
www.ntechengineering.com
(863) 324-6692
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