Anyone using 2.5"+ /3" N/A exhaust system???


Thats prity loud mate. Have to say sounds quite farty. What type and size of back box do you have??
 
KieranEG6 said:
Thats prity loud mate. Have to say sounds quite farty. What type and size of back box do you have??
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The sound on the video isn't great i'll admit, it far quieter than most systems......and doesn't sound at all farty in real life haha.


The whole system is a custom made by solid fabrications, the back box is modeled on the j's dolphin system with a 3" tip.

89888762.jpg
 
Any chance you could make a video from a distance instead of right beside the exhaust?
 
Ernie said:
This isnt true, dozens of threads on HondTech showing gains all through the rev range...

A guy posted a graph of a stock b16a with a 3" sytem bolted to it and it still gained power and torque all over.

All the info is out there.
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The web is a big place. Show us some proof. On a k-series I believe. Not on a average B16. Its easy to make more HP/torque with the k20 in lower rpms because you have VTC.

I've went from 2.25" to 2.5" on my EK9 and you do loose bottom end till about 5000rpm. Felt it straight away. However, the top end is very nice.

HP is related to Airflow CFM. A 1.6L that makes 100hp @ 5000rpm is only going flow a certain amount of air and a 3" exhaust isnt going to help speed up the exhuast flow to help with scavenging which happens inside the combustion. No scavenging = less volumetric efficiency = less power.

I'd like to be proven wrong because theory has its limits. But no ordinary B16 would ever benefit from a 3" exhuast. We all don't have 15:1 compression B16s running on alcohol that only lives at the drag strip for only 13 secs of joy.
 
meh did a little research myself. He has a 1.8.

I guess 1 day I might change my muffler only to a 2.75-3" because the end tip of the 2.5" muffler is actually not a true 2.5". Its like 2.36 due to its design to hold the packing in.

3" exhaust...too big for n/a? - Page 2 - Honda-Tech

The dude says;

Update:
I tuned with the 3" exhaust. I made good power however I know my midrange was suffering and the car wasn't loud....it was ****ING RETARDED LOUD!(hollowed cat, no resonator, 3" straight through muffy) It was to the point where, I would get home and my ears were buzzing and ****(felt like I'd been partying at a club all night ). Anyhow, I recently swapped the exhaust for 2 1/2" cat back setup. I still retained a 3" outlet on my header, ran a 3" high flow cat, then tappered down. The car feels a lot better. Tq is definately beneifiting from the smaller diameter piping. I will have numbers up soon.

I think the general consensus is, 3" is a little on the big side for 81-82mm(stock sleeve) setup. Peak power will be greater however its all about the power under the curve.
 
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I could ask where your proof is?

At the end of the day day, if your happy with what you have and I am happy going 3" its all good.
 
jugbugz said:
meh did a little research myself. He has a 1.8.

I guess 1 day I might change my muffler only to a 2.75-3" because the end tip of the 2.5" muffler is actually not a true 2.5". Its like 2.36 due to its design to hold the packing in.

3" exhaust...too big for n/a? - Page 2 - Honda-Tech

The dude says;

Update:
I tuned with the 3" exhaust. I made good power however I know my midrange was suffering and the car wasn't loud....it was ****ING RETARDED LOUD!(hollowed cat, no resonator, 3" straight through muffy) It was to the point where, I would get home and my ears were buzzing and ****(felt like I'd been partying at a club all night ). Anyhow, I recently swapped the exhaust for 2 1/2" cat back setup. I still retained a 3" outlet on my header, ran a 3" high flow cat, then tappered down. The car feels a lot better. Tq is definately beneifiting from the smaller diameter piping. I will have numbers up soon.

I think the general consensus is, 3" is a little on the big side for 81-82mm(stock sleeve) setup. Peak power will be greater however its all about the power under the curve.
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Scavanging is almost all controlled by the header design, collector type and size. When it comes to tail pipe dimentions you should be going for as free as possible. Well to an extent. I would agree 3" is too big for a b16. But this thread was about higher tuned b18's to K20's. Plus to point out that guy was runing a 3" header aswell, so no wonder it didn't suit, as he has changed the header design. Im still yet to be convinced on the idea of 3" being best. I know people have proved it on dyno's but I do understand the fact that doesn't show what partial throttle will be like.
 
KieranEG6 said:
Scavanging is almost all controlled by the header design, collector type and size. When it comes to tail pipe dimentions you should be going for as free as possible. Well to an extent. I would agree 3" is too big for a b16. But this thread was about higher tuned b18's to K20's. Plus to point out that guy was runing a 3" header aswell, so no wonder it didn't suit, as he has changed the header design. Im still yet to be convinced on the idea of 3" being best. I know people have proved it on dyno's but I do understand the fact that doesn't show what partial throttle will be like.
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Correct the magic is in the header not the catback! Hence you don't see engines been tested on a engine dyno with a catback exhaust hanging off the manifold;)
 
but the main thing is to tune the car
if you install a 76mm exhaust and no tune there will be a loss for sure in power
60mm is bigger than oem exhaust and so is 70mm and 76mm ...
personally i feel my car faster everywhere part throttle from 3rd 4th gear , wot etc.
most times the best power comes open header for a reason ...
 
I just fitted a 3" cat back to my car, h22a7 with breathing mods, filter, vtec. Direct manifold, so-fab 2.5" decat and now 3" cat back.(was dyno'd at 229bhp before manifold/decat) My previous exhaust was a 2.25", its a really wierd set up now, for every day driving, when just cruising around it feels ALOT less restrictive, but when i'm at about 2-4k and boot it, it does feel quite sluggish, but as vtec comes in it does seem to pull alot harder than previously, but thats only from the bum dyno :)
 
fez said:
I just fitted a 3" cat back to my car, h22a7 with breathing mods, filter, vtec. Direct manifold, so-fab 2.5" decat and now 3" cat back.(was dyno'd at 229bhp before manifold/decat) My previous exhaust was a 2.25", its a really wierd set up now, for every day driving, when just cruising around it feels ALOT less restrictive, but when i'm at about 2-4k and boot it, it does feel quite sluggish, but as vtec comes in it does seem to pull alot harder than previously, but thats only from the bum dyno :)
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Was it remaped with the new setup?
 
Yeah a tune would make a world of difference, so damn expensive though :(
 
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