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Mar 24, 2011 | 10:49 PM

#41

Blownz28man

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From: OK,Elk City

Thats a lot of restriction.. Cut 2500HP in half, thats 1250HP now cut the cross over in half, thats 1.25". I dunno if it works like that but I'm just brainstorming... Hell in my build I'd be happy with 700hp not 1250 but that would be nice too!

Mar 25, 2011 | 08:02 AM

#42

Phil99vette

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From: Port Tobacco, MD

Quote:

Originally Posted by Blownz28man

Airflow cuts in half, not tube size.

Mar 25, 2011 | 12:49 PM

#43

slow67

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From: DFW

Quote:

Originally Posted by Phil99vette

2.25" is not too small for a crossover tube on any of the street cars on this forum, honestly I think 2" or 2 1/8" would work very very nice. Its all about heat retention and velocity. We plan on making over 2500hp and still will use a 2.5" crossover if that tells you anything, if you want to talk about restriction, how much restriction is in a 2.5" pipe and 2500hp.

I'm thinkin it may be less of total hp, and more of how much the motor is N/A (since it can perform similar under boost vs N/A). Either way, I'm going to find out how a 2" crossover does on a stock 5.3 (16 gauge, so 1.87" ID).

I think the crossover should be sized on the motor's airflow (based on CID and approximate N/A VE). I don't think it should matter if your shooting for 2500hp or 1500hp, if the motor is the same (since its only a change in boost level, assuming the same motor and the motor can handle it).

Mar 25, 2011 | 02:39 PM

#44

Phil99vette

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Quote:

Originally Posted by slow67

So you would use the same size exhaust plumbing on a 427 street motor with a pair of billet 72s making 1200hp as a 427" race motor with a pair of pro-mod 91s making 3100hp.

Mar 25, 2011 | 04:04 PM

#45

slow67

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From: DFW

Quote:

Originally Posted by Phil99vette

So you would use the same size exhaust plumbing on a 427 street motor with a pair of billet 72s making 1200hp as a 427" race motor with a pair of pro-mod 91s making 3100hp.

I would if the motor was exactly the same.

Mar 25, 2011 | 04:47 PM

#46

Phil99vette

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Quote:

Originally Posted by slow67

I would if the motor was exactly the same.

I guess we disagree on this one, IMO the exhaust pipes need to be sized based on how much power the system will make. The pre turbo pipes need to be sized based on velocity not NA engine HP.

Mar 25, 2011 | 05:07 PM

#47

slow67

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From: DFW

Quote:

Originally Posted by Phil99vette

I guess we disagree on this one, IMO the exhaust pipes need to be sized based on how much power the system will make. The pre turbo pipes need to be sized based on velocity not NA engine HP.

Fair enough. I base my theory on that the velocity (in FPS) would be the same, only denser (since its a higher P/R).

Mar 25, 2011 | 07:49 PM

#48

kmracer

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From: Washington DC

Quote:

Originally Posted by slow67

I would if the motor was exactly the same.

boost in and boost out. while the cubes are the same, nothing else in the combo is.

should you run the same headers on an 600whp 427 as you do on a 3000hp procharged car?