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  #25  
Old 09-04-2011, 02:13 PM
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Re: 3.7l performance love

Who makes the underdrives ??
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  #26  
Old 09-04-2011, 02:57 PM
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Re: 3.7l performance love

Ati, asp...
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  #27  
Old 09-04-2011, 08:05 PM
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Re: 3.7l performance love

I am thinking of pulling the trigger on the Gibson catback system for the 3.7L. I like this model because it increases the pipe diameter to 3", versus the stock 2.5"

My only concern.... will this increased flow reduce backpressure too much and cause a noticeable decrease in torque? I have read both sides of this, and some says its a myth. Anyone have any input?
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  #28  
Old 09-04-2011, 08:37 PM
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Re: 3.7l performance love

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Originally Posted by jvs0302 View Post
I am thinking of pulling the trigger on the Gibson catback system for the 3.7L. I like this model because it increases the pipe diameter to 3", versus the stock 2.5"

My only concern.... will this increased flow reduce backpressure too much and cause a noticeable decrease in torque? I have read both sides of this, and some says its a myth. Anyone have any input?
Backpressure is a myth. I like to think of it in terms of energy (heat), flow, and velocity.

If you put on too large of piping, you'll have all the flow you need, but because it will take longer for the hot exhaust airmass to move (reduced velocity), you losevthat heat energy. Exhaust gases need heat to move on out. This is why many resort to wrapping or coating their exhaust, to retain that energy.
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  #29  
Old 09-04-2011, 09:09 PM
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Re: 3.7l performance love

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Originally Posted by FlyinRyan View Post
Backpressure is a myth. I like to think of it in terms of energy (heat), flow, and velocity.

If you put on too large of piping, you'll have all the flow you need, but because it will take longer for the hot exhaust airmass to move (reduced velocity), you losevthat heat energy. Exhaust gases need heat to move on out. This is why many resort to wrapping or coating their exhaust, to retain that energy.
so in your opinion, if i increase the diameter to 3in after the cats, would i be losing too much heat energy, and therefore slowing the velocity of the exiting exhaust gases?
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  #30  
Old 09-04-2011, 10:04 PM
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Re: 3.7l performance love

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Originally Posted by jvs0302 View Post
so in your opinion, if i increase the diameter to 3in after the cats, would i be losing too much heat energy, and therefore slowing the velocity of the exiting exhaust gases?
I think you'll be just fine. Id do 3" if I had a 3.7 too.
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  #31  
Old 09-05-2011, 08:06 AM
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Re: 3.7l performance love

Anybody ever considered the CNC ported heads from ARP?

http://www.airram.com/product.php?ca...productid=1241

or

http://www.airram.com/product.php?ca...productid=1240
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  #32  
Old 09-05-2011, 08:39 AM
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Re: 3.7l performance love

Killian will also do them....and he is much cheaper. Although he hand ports them. He has a flow bench in house and 40 years of experience so there is little if any difference between ports.

I can also port heads upon request but without a flow bench it is alot of work making sure everything is symmetrical. I can do clean up/minor porting, anything else Id prefer to have a flow bench to back everything up. Whenever I move into a house (hopefully early next year), I plan on making a flowbench.
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  #33  
Old 09-05-2011, 03:21 PM
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Re: 3.7l performance love

Kilian?
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  #34  
Old 09-05-2011, 04:01 PM
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Re: 3.7l performance love

Quote:
Originally Posted by 05wkguy View Post
Kilian?
Jerry/Gerry Killian. Killians Porting Service. Google it
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  #35  
Old 09-05-2011, 06:16 PM
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Re: 3.7l performance love

How much would the ported heads mod, out the door, run from that killian guy?

And what gains/losses could be expected depending on the bore?
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  #36  
Old 09-06-2011, 12:28 AM
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Re: 3.7l performance love

Dang! His work looks good.

http://killiansportingservice.com/id2.html

No real pricing on his site tho...
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