ok, I got my h22 out of the shop about 2 months ago, i dynoed at 213 hp and like 168 tq. with open header. With my 5zigen fireball catback it only pulled like 199 hp and like 15X tq. The mechanic said that its because of my street exhaust and i need my pipings to be bigger, like 2.75-3" (race exhaust). Shouldn't my exhaust work for my motor?

 

what all is done to your motor?

 

I guess it would help. But what header are you using?

2.75 that is.........
I think 3" is too big for that hp..........maybe for FI

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMH22NLINE4 &raquo;</TD></TR><TR><TD CLASS="quote">ok, I got my h22 out of the shop about 2 months ago, i dynoed at 213 hp and like 168 tq. with open header. With my 5zigen fireball catback it only pulled like 199 hp and like 15X tq. The mechanic said that its because of my street exhaust and i need my pipings to be bigger, like 2.75-3" (race exhaust). Shouldn't my exhaust work for my motor? </TD></TR></TABLE>

you should try a real 2.5 setup, your 5 zigen is probably 60mm, and probably has a bottleneck out of the "cat"....what catalytic setup do you have??

and list out your mods please

 

Mods are:

PnP head (milled .030) by ldl speedshop
Crower titanium retainers
Crower valves
Crower springs
Crower stage 2
Fidanza camgears
RC injectors, i think they are 350 or something.. not sure
Skunk2 IM
JG 70mm TB
CP 11.5 pistons
Eagle rods
89mmx90mm sleeved by golden eagle
p28 with s200
DTR 4-2-1 race header with straight pipe
fidanza flywheel
ACT XT SS clutch
msd digital 6

i think thats it...

 

wow im surprised it dynoed so low....could be the shitty skunk2 manifold, or possibly the port job...

either way, you can run a 2.75 or 3 inch.....it will be good....

 

2point6 has crush bent 2.5" and he's making 260 whp isn't he?

 

3" will do nothing for you but rob you of low-end and mid-range hp. it probably won't even give you more up top.

the only reason to run 3" on a four-banger is if it's got a turbo, or it's got ****-tons of displacement (like a Porsche 968: 3.0L I-4)

 

or if the header's collector is 3 inch....2point6's new header has a 3 inch collector....

crush bent is robbing him of hp

he could go with 3 inch, seriously, talk to rlz.....there are cars that would suffer from that....but this guy i dont think would.....

 

I kinda thought that it was making low hp but peeps keeps saying that thats good #s, so getting a bigger exhaust would definitely get more hp or it's not worth it?

 

with your setup, i'd say 2.5 ID should be good enough.

3 is WAY too big unless you plan on going serious turbo or serious NA (250+whp).

 

I would make sure you have a 2.5 inch collector and catalytic converter inlet, then out of the converter use 3.0 inch and a quiet muffler. If you don't have a converter then run a length of 2.5 inch in the collector, then use a taper to open it up to 3.0 inch.

I have 2.5 inch for my system, and I regret not buying 3.0 inch every day. Big tubing will always help with flow and power, so use big tubing to reduce losses, and use a good muffler to keep the noise down.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">or if the header's collector is 3 inch....2point6's new header has a 3 inch collector....

crush bent is robbing him of hp

he could go with 3 inch, seriously, talk to rlz.....there are cars that would suffer from that....but this guy i dont think would.....</TD></TR></TABLE>

I am running a 3" mandrel bent now, but with full exaust, I am just about 252 whp and 260 whp without exaust. I am not sure if a smaller diameter would work for me or not. Randy built the exaust which sounds WICKED but I dropped power with the exaust... no more crunch bent piping though.