High flow cat converter dyno result
#1
High flow cat converter dyno result
I went to the dyno today to see if the cat provides any gain before I bolt up the custom A-pipe. This way I know what works and what not. Today's temp is about 10 degrees F hotter than the last dyno. So I kind of expect some variations. Here we go...
No peak gains but that also means the big bore TB still providing the same peak hp and repeatable. The cat actually causes come loss from low to mid range prior to vtec. I wonder if this is the result of component mismatch as I'm still using the stock catback exhaust. I believe other members felt some gains with their aftermarket catback system. So, based on this result, the cat is off until I can test it again with a catback system. I probably wont' install the custom A-pipe until then.
No peak gains but that also means the big bore TB still providing the same peak hp and repeatable. The cat actually causes come loss from low to mid range prior to vtec. I wonder if this is the result of component mismatch as I'm still using the stock catback exhaust. I believe other members felt some gains with their aftermarket catback system. So, based on this result, the cat is off until I can test it again with a catback system. I probably wont' install the custom A-pipe until then.
![](http://www.tsobad.com/jtso/Images/Cat%20converter/Cat%20dyno.jpg)
#5
What do you mean by custom A-pipe? It this somehow to avoid doing an actual header upgrade? I'm still learning what works and why.
I am not surprised the cat dropped low end tq like that. But am not sure what to expect fom the exhaust.
I am not surprised the cat dropped low end tq like that. But am not sure what to expect fom the exhaust.
#7
Originally Posted by Asahi
What do you mean by custom A-pipe? It this somehow to avoid doing an actual header upgrade? I'm still learning what works and why.
I am not surprised the cat dropped low end tq like that. But am not sure what to expect fom the exhaust.
I am not surprised the cat dropped low end tq like that. But am not sure what to expect fom the exhaust.
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#8
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Gains usually arent that great if you just replace a single part of your system. The most effective way is obviouly to increase the flow from the exhaust ports back. Otherwise its not going to provide much performace at all. If you think about it like breathing through a straw, if you increase your lung size your still not going to be able to breath any better untill you increase the straw diameter.
#9
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Looks like I won't be doing this mod. I definitely don't wanna lose low/mid end torque.
I bet having a aftermarket exhuast would help. I'll be interested to see what happens when you get a new exhuast.
Thanks for doing the dyno Jtso. Saves me some time/money
I bet having a aftermarket exhuast would help. I'll be interested to see what happens when you get a new exhuast.
Thanks for doing the dyno Jtso. Saves me some time/money
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#11
Suzuka Master
Originally Posted by rmpage
Man, that's strange, I wonder how big a bottleneck the stock catback is.
Thanks for the graph.
Thanks for the graph.
#13
Drives With Hands
I should try doing two pulls with the catback disconnected to get the most accurate comparison between the two cats.
If I knew how to get around the fact that it would look extremely silly, I'd have a custom single exhaust on my car by now. Magnaflow resonator and straight-through muffler would be the sexy sweetness.
If I knew how to get around the fact that it would look extremely silly, I'd have a custom single exhaust on my car by now. Magnaflow resonator and straight-through muffler would be the sexy sweetness.
#14
Photography Nerd
Originally Posted by rmpage
If I knew how to get around the fact that it would look extremely silly, I'd have a custom single exhaust on my car by now. Magnaflow resonator and straight-through muffler would be the sexy sweetness.
#15
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Originally Posted by kurt_bradley
It's bad. If you go with a one-muffler design, you'll see some serious gains. For the most part, aftermarket cat-back systems haven't yielded too wild of gains. They've all been in the range of 8-10 whp, but, of course, most of the buyers of these systems are going after tone more so than gains.
http://www.comptechusa.com/dyno.htm#tsx
Maybe the stock system isn't that bad. Of course, the only way to be sure is to dyno with everything else upgraded, and change the catback last, and dyno again.... Recently, someone suggested that you need to upgrade the whole system to see results? Well, it'll be interesting to see any dynos that test these theories.... :-)
#16
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Originally Posted by Dan Martin
I think you could get around the silly look by using the rear bumper from the Euro Accord. I don't remember which model has it, but one comes stock with a single exhaust.
So, what's the problem with two mufflers? Not enough backpressure or something?
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#17
Photography Nerd
Originally Posted by vidgamer
So, what's the problem with two mufflers? Not enough backpressure or something? ![Wink](https://acurazine.com/forums/images/smilies/wink.gif)
![Wink](https://acurazine.com/forums/images/smilies/wink.gif)
#18
Drives With Hands
Originally Posted by vidgamer
Maybe the stock system isn't that bad. Of course, the only way to be sure is to dyno with everything else upgraded, and change the catback last, and dyno again.... Recently, someone suggested that you need to upgrade the whole system to see results? Well, it'll be interesting to see any dynos that test these theories.... :-)
Originally Posted by Dan Martin
Not backpressure, low exhaust velocity.
#19
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With a single exhaust you can smooth out the flow where you would have had that Y-pipe. You could probably also save 40 lbs. IMO dual pipes on a car with only one exhaust bank is purely an esthetic issue. You don't see many dual exhaust 4 cylinder race cars...
#20
Burning Brakes
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What do y'all think of the "No Loss Exhaust" article here: http://www.ntpog.org/articles/index.shtml
If I read that correctly, once past the resonator, the exhaust simply needs to flow sufficiently.
You might replace the header and cat and still find that replacing the catback does nothing for you because it just isn't that restrictive. Maybe! Is there a dyno showing an exhast change after someone has completed header & cat mods?
For an amount of air flowing out of the engine, you're going to reach a case of diminishing returns at some point.
My guess is that the header is restrictive, but the other parts, less so. I will be curious to see the dynos that prove otherwise!
If I read that correctly, once past the resonator, the exhaust simply needs to flow sufficiently.
If the biggest bottleneck is in the header, changing the cat and catback may help a tiny bit but won't really be worth it unless you do the header too. If there is a bottleneck upstream, anything replaced downstream will be a waste of time.
For an amount of air flowing out of the engine, you're going to reach a case of diminishing returns at some point.
My guess is that the header is restrictive, but the other parts, less so. I will be curious to see the dynos that prove otherwise!
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#21
Drives With Hands
Originally Posted by vidgamer
You might replace the header and cat and still find that replacing the catback does nothing for you because it just isn't that restrictive. Maybe!
#22
rumor has it that someone witha 6MT who has intake, exhuast, header, hondata, hondata intake manifold gasket is now acquiring a high flow cat.
i wonder how much that would put down.
:troutslap
i wonder how much that would put down.
:troutslap
#23
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Originally Posted by dzuy
rumor has it that someone witha 6MT who has intake, exhuast, header, hondata, hondata intake manifold gasket is now acquiring a high flow cat.
i wonder how much that would put down.
:troutslap
i wonder how much that would put down.
:troutslap
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#24
Burning Brakes
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did anyone end up finding out about the exhaust outlet cover in the other thread with the red accord from europe?
That'd be an ideal solution.
That'd be an ideal solution.
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