skinny z

Found this too.

http://www.exhaustsoundclips.com/cfm.pdf

thebufenator

I wish there were some 3" inlet tests......

skinny z

Mufflers or pipe?

thebufenator

Mufflers.

I am running 3" all the way out

Batass

Can anyone recommend a collector calculator? Besides the one that costs 40 bucks. I've used three so far and gotten three different answers.

And none that I have seen take boost into account which will raise the cfm output correct?

Orr89RocZ

yes boost should change things but from what i'm seeing boosted motors dont really change much powerwise from pipe size. They should but some guys are making nasty power numbers with boost thru stock style 3" single setups when they should be using 4"

Boosted motors are suppose to be modeled or considered as larger cubic inch n/a motors. how true is this i'm not sure but it does make sense in a way

Say you have 800 hp on motor boosted, thats 880 cfm per bank required to allow that motor to exhale. 3" is 812 cfm so you'll need atleast 3" duals or better yet, dual 3.25-3.5". Dual 3.5's are overkill and you cant find 3.25" so use dual 3". For a single you'll need something like 4.5" which isnt gonna happen either.

Batass

It's got dual 3 on it now with dual ultraflow welded muffs. The xpipe is halfway down the driveshaft, not the best spot. Hooker 2210's and dumping at axle out of mufflers.

On the exhaust side, it may have to do with some boost pressure going through the cylinder into the exhaust. Especially mine with a 110 lsa. Flames shoot out the tail!

I might not have much to benefit from tuning a cutout.

skinny z

[quote=Orr89RocZ;3868355] They should but some guys are making nasty power numbers with boost thru stock style 3" single setups when they should be using 4"

QUOTE]

The same applies to all types of modified engines. Impressive performance with less than optimum specs. Kind of makes you wonder what kind of power they SHOULD be making if everything was perfectly designed and matched.
A little guy like me depends on getting the details right so I can extract all the power that's available from my combo.
That's why this thread has become so interesting. We're working on things that are overlooked or dismissed by others. Mind you if you have an 800 hp turbo engine, maybe you can afford a less than 100% set up.
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I found a few muffler flow specs on line however as Orr has suggested to me, there isn't a single testing value, ie test pressure, that I can say is used universally.
Can't compare the Borla from one test with a Dynomax from another because of different testing methods. It might be a question that could be raised on the Go Fast News forum.

1989GTATransAm

Hey Orr, any updates? Any new dyno or track results?

skinny z

He's too busy running 11.50's!

Orr89RocZ

rained out this wednesday. rescheduled fro tomorrow but looks like rain again and i have other things goin on anyway. Just finished installing subframe connectors these past 2 days took longer than i thought but i didnt have much room to work with under the car.

Havent driven the car since last week at the track. Started it up today moved it around in the driveway. The bumps from the driveway exit and the raised lip goin into the garage were used to test the SFC's. They feel awesome! The car doesnt shake much at all, and it feels sooo much smoother

I hope this helps my launch as i know the car was twisting bad!! I posted a pic in the drag section of me pulling the right front wheel about 3 inches before the suspension unloaded and the car spun. The front is twisting bad

So hopefully the subframes help

On the side note, i didnt measure the location for cutouts but i estimate they will be in the straight section that ducks under the frame rails so they should fit good. I'll order cutouts tonight i guess and hopefully work on that over next weekend or so depending

Hopefully i can schedule dyno time again

1989GTATransAm

Sounds good.