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2 1/2 flowmasters enuff for the hemi?

Posted By: toplescuda

2 1/2 flowmasters enuff for the hemi? - 06/28/11 03:44 PM

pulling a stock build 440 out of the challenger
will be putting in a nice 426 hemi (alum head,alum rod,590/600 solid roller,tunnel ram,2 inch headers)
car has a 2 1/2 inch 3 chamber flowmaster system now
will that be enuff or do i need to step up to 3 inch(will still be flowmasters)
Posted By: GomangoCuda

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 04:41 PM

Thats a lot of motor for 2 1/2" exhaust. Definately should step up to 3". Might want to concider 3 1/2 from the headers to an x-pipe and then come out of the x-pipe with 3".
Posted By: Dragula

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 05:05 PM

Min is really 3"....And I have an X pipe in 3" if interested. Heck I run 3" on my 360!
Posted By: HEMIFRED

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 05:07 PM

Quote:

2 inch headers




Posted By: 68 HEMI GTS

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 05:36 PM

i run 4" in on my hemi with no tail pipes. still picks up a tenth and a half when you pull them off. if you have 3 1/2 collectors i'd run 3 1/2 in exhaust.
Posted By: justinp61

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 05:41 PM

No, I had Flowmaster 40s with turn downs at the axle on my Dart when it had the 340 in it. On back to back runs it slowed .2 in the 1/8.
Posted By: quickd100

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 06:23 PM

I run 3-1/2" Ultra Flows on my 528 Hemi. A 4" system probably wouldn't hurt either. Dave
Posted By: Thumperdart

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 08:08 PM

I wouldn`t put "choke masters" on anything if they were given to me unless they were the race series then MAYBE. Throw some bullets on that puppy and let it breathe.
Posted By: Labratt

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 09:24 PM

2.5" exhaust for a modified Hemi??? That baby's gotta breathe! 3" minimum..and like Fred thinks..2" headers will be restricting that motor. Sounds like you need to re-think your whole exhaust system...if you want it to be efficient,and make the power that it should. Best of Luck with it!
Posted By: Dragula

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 09:26 PM

Quote:

I wouldn`t put "choke masters" on anything if they were given to me unless they were the race series then MAYBE. Throw some bullets on that puppy and let it breathe.




My street hemi exhaust is 3" choke master 40's, and going from those to bullet's in 3.5, I see over 10% change in the fuel map. That's a lot on a +700hp engine. My current favorite muffler is Hooker Aero Chambers, good sound and really good flow...
Posted By: Cab_Burge

Re: 2 1/2 flowmasters enuff for the hemi? - 06/28/11 10:00 PM

Quote:

pulling a stock build 440 out of the challenger
will be putting in a nice 426 hemi (alum head,alum rod,590/600 solid roller,tunnel ram,2 inch headers)
car has a 2 1/2 inch 3 chamber flowmaster system now
will that be enuff or do i need to step up to 3 inch(will still be flowmasters)


Heck no, I had a 440 in a 1969 dart that had a set of Hooker two inch headers with 3.5 collectors, 2.5 pipes to a set of Turbo muffs and then out the side in front of the rear tires. The car ran 12.23 ET at 109.45 MPH with the exhaust sytem on and ran 11.39 at 117.65 MPH with the pipes and mufflers off A deep breating Hemi should have at leats a three inch system, 3.5 would be better Get rid of the mufflers with baffles in the way of the exhaust flow, buy a set of muffs that flow straight through
Posted By: toplescuda

Re: 2 1/2 flowmasters enuff for the hemi? - 06/29/11 01:37 AM

i like the echo sound of the flowmasters
i fig the motor might make 600hp (pump gas)
i dont know if their 2 inch headers but do know their NOT 2 1/4
havent measured the collectors to see what size they are yet
i hate magnaflows and i wont take anything from hooker if you gave to me
iv learned my lesson with their junk headers
gonna call tommarow and see what size pipe the muffler shop can bend
not gonna be able to bend real big over the rear so prob will have to exit like old system did t/a style (rember challenger)
Posted By: Bob_Coomer

Re: 2 1/2 flowmasters enuff for the hemi? - 06/29/11 02:17 AM

There easily changed. The ones I have had taper. I have cut a few 2.5" Flow Master and made them 3" sized inlets/outlets..
About a 10 minute fix with a Mig. The mufflers them selves are the same.
Posted By: toplescuda

Re: 2 1/2 flowmasters enuff for the hemi? - 06/29/11 07:52 PM

well it gonna be 3" as no shop around here can bend anything bigger
if ever take it to the track will just have to un cork it
lol not that its gonna hook up anyway with the lil tires on back
Posted By: Cab_Burge

Re: 2 1/2 flowmasters enuff for the hemi? - 06/29/11 07:57 PM

There is another option that you can take, order some 180 degree 3.5 inch mandrel bends and some 3.5 inch straight pipe and have a system cut and welded on your car
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