Best size exhaust?

rick_I_S · Post by **rick_I_S** » Sat Oct 06, 2012 7:18 pm

looking into getting a new exhaust as mine is going to pieces. Which size is the best for the h22a7 as i been told a 3" system would be best but then someone else has been saying 2.5" would be better. also seen a system at 2.75"

Think i will be going for 2.5 as its an easy off the shelf system and its proving hard to find a decat to fit from 2.5 to join onto anything bigger as i have a civic so cant use accord decat unless i get a different flange put on.

Any help is great thanks

Rick

mercutio · Post by **mercutio** » Sat Oct 06, 2012 7:21 pm

depends on what else you have done to the car a 3" exhaust on a standard car will likely lose a bit of power/torque and drop fuel economy

Post by **NafemanNathan** » Sat Oct 06, 2012 7:22 pm

2.5" is the best for a standard H22a7 (ideally mandrel bends). 3" would be massive for anything that isn't turbo'd really, you'd likely loose torque due to lack of back-pressure. I'll be going for a 2.75" custom system eventually, but I'm hoping to be achieving 275bhp+.

This 2.75" system you've seen a custom fabrication I take it?

Greg · Post by **Greg** » Sat Oct 06, 2012 7:29 pm

I would keep it at 2.5" there really is no point in going bigger the back pressure helps the gasses flow, I would spend cash on 4-2-1 manifold and a port and polish.

Post by **RattyMcClelland** » Sat Oct 06, 2012 7:30 pm

H22 makes more power on a 3" than a 2.5". The fat yanks dyno proved it. 3" is actually alot more power. But too loud.

Post by **rob quilter** » Sat Oct 06, 2012 7:35 pm

2 words.....solid fabrications.

Post by **NafemanNathan** » Sat Oct 06, 2012 7:50 pm

RattyMcClelland wrote:H22 makes more power on a 3" than a 2.5". The fat yanks dyno proved it. 3" is actually alot more power. But too loud.

Where's that thread?

EG_H22 · Post by **EG_H22** » Sat Oct 06, 2012 8:01 pm

Bro your going to have to go custom, 3" system like i said on CL, 2.5" is fine but you get better torque with the 3" plus will work with your 275 bhp.
Im going for 300 and with what im doing.
If u need help just ask me on here or on CL bud

EG_H22 · Post by **EG_H22** » Sat Oct 06, 2012 8:02 pm

NafemanNathan wrote:
RattyMcClelland wrote:H22 makes more power on a 3" than a 2.5". The fat yanks dyno proved it. 3" is actually alot more power. But too loud.
Where's that thread?

Its on HT bud,

Post by **NafemanNathan** » Sat Oct 06, 2012 8:05 pm

Ah, didn't realise he had 275bhp.

As said though, I'm aiming for 275+ and I'm going for a 2.75" system under recommendation from Rich at PAW... That's all the information I need to hear