Is my exhaust too Big

[jules325i]

I have a 2.9 m20 stroker 10.5:1 schrick 272 with extensive head work.
My exhaust set up is 1 5/8" 39mm port extractors to twin 2 inch system through twin high flow cats, to rear muffler.

I have very little power from 4500rpm.
Or could this be down to stock injectors (soon to be changed.)

[Hey_You]

Big exhaust shouldn't be hurting you up top, I would look for your problem elsewhere

[MR 325]

Stock injectors on a 10.5:1 2.9L? Yikes. Get that thing tuned! I'd have run a bigger cam myself too.

[sayed ali]

stock injectors on a 10.5:1 2.9l? Yikes. Get that thing tuned! I'd have run a bigger cam myself too.

+1

[F34R]

All that^

19lb injectors and a tune will fix your problems. How "extensive" if your head work? Port matched?

[jules325i]

I got full port and polish, mutiangle valve job, and a few other little thing ill have to dig the invoice out.
I have some ford type 3 19lb injectors on there way hopefully they will sort the problem out is there a recommended chip to run with big injectors or megasquirt.

[e30leigh]

pics of the exhuast? my experiance is the m20s like to breath. 2" might be too small. choking your flow uptop. if you dont want to go to bigger pipes. put a "X" section in shortly after the headers but before cats. it will double the flow. should give you heaps more top end. or your rear muffler might be too restrictive. we dyno'ed a car with a high flow rear straight through muffler vs a chambered "performance" muffler. and the chambered one lost us 40hp and the wheels. it was hard to believe if i hadnt seen it with my own eyes.

[jules325i]

i do have a y pipe just after the headers. sorry i didn't include that.
i spent a lot on the system Ill take a photo today and upload it.
The rear muffler is quite long and silencing.

[ak-]

It's all in your headers. Just free flow the headerback piping.
Either get a dyno tune(reflash), or megasquirt.

[nando]

No such thing as too big of an exhaust, except for added weight, reduced ground clearance, and extra cost.

This assumes your headers are right for the engine, because those can definitely have primaries that are too big.

You need injectors and a tune. Time to ditch motronic. An adjustable cam gear will help too.

[JCarp90]

This assumes your headers are right for the engine, because those can definitely have primaries that are too big.

You need injectors and a tune. Time to ditch motronic. An adjustable cam gear will help too.

This. Now, sell me your 272 and pony up for a bigger cam.

[jules325i]

This. Now, sell me your 272 and pony up for a bigger cam.

Im very happy with my 272 as my DD.
so I'm keeping it.

[JCarp90]

im very happy with my 272 as my dd.
So i'm keeping it.

awwwwww :(