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Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 02-10-2007, 04:33 PM   #21
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Quote:
Originally Posted by willwren
I checked on the Gears also, and you're right on the 2.93'* for stock GTP'*. My bad on that one.

I'll write yours off to the lighter car making it less noticable.

Most people don't mess with a 3" dp until they have rockers or a cam, and headers as well. I don't think you're going to gain anything noticable with a 3" dp on PEM'*.
On the lighter car note "Foghorn" has pointed out to us that the 96-99 bonnevilles are similar in weight to the GTP.

Quote:
Originally Posted by Foghorn
Just to debunk one notion going around;

The 97 to 99 SSEi is about equal in weight to a 97 to 03 GTP 4 door

I've been on a scale with my car and a buddies 1999 GTP 4 door on the same day, same scale and they were within 20 Lbs of each other.
Also I hope 'billboost' chimes in to better explain his expierence with the 3" downpipe.
Many people on other w-Body forums have had good expierences with the PEMs & 3" dp combo. (sorry for the spelling)
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Old 02-10-2007, 04:35 PM   #22
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That'* because the stock downpipe on the GTP has a restrictive U-bend in it. You can't make that comparison.
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Old 02-10-2007, 04:51 PM   #23
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Quote:
Originally Posted by willwren
That'* because the stock downpipe on the GTP has a restrictive U-bend in it. You can't make that comparison.
I am not understanding your statement? They always do the U-bend delete before anything else, it is after the downpipe . They wouldn't run a 3" DP, PEM or Headers with it.
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Old 02-10-2007, 04:57 PM   #24
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The U-bend IS the downpipe on a Grand Prix.


http://www.zzperformance.com/grand_p...=504&catid=110

They gain mostly from the U-bend delete. That'* the point I'm trying to make. It'* a restriction, far more than a stock DP on a Bonneville, which has no bend.
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Old 02-10-2007, 05:07 PM   #25
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Quote:
Originally Posted by willwren
The U-bend IS the downpipe on a Grand Prix.


http://www.zzperformance.com/grand_p...=504&catid=110

They gain mostly from the U-bend delete. That'* the point I'm trying to make. It'* a restriction, far more than a stock DP on a Bonneville, which has no bend.
Nope, U-bend is after the Cat.

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Originally Posted by ZZP
Stock downpipes are double-walled tubing with an inside diameter of just over two inches. Following the restrictive downpipe section, the stock unit subjects the exhaust gases to the choking effects of the catalytic converter. After the cat, it flattens out into a section dubbed the infamous "U-Bend
http://www.zzperformance.com/grand_p...=551&catid=110

They still see a noticeable difference with the 3" dp . With the U-bend gone. But like I said they wouldn't do the DP without the U-bend Deleted. I know that the bonneville has a less restrictive exhaust but the poster asked if there was room for improvement on the exhaust, the downpipe can stand some improvement.
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Old 02-10-2007, 05:18 PM   #26
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Quote:
Originally Posted by willwren
Explain billboost'* loss of low-end with the same mods and a 3" dp?
Some people'* butt dyno'* are off.....
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Old 02-10-2007, 05:34 PM   #27
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Quote:
Originally Posted by chadow427
Quote:
Originally Posted by willwren
Explain billboost'* loss of low-end with the same mods and a 3" dp?
Some people'* butt dyno'* are off.....


Lets see what he says. :P
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Old 02-12-2007, 09:20 PM   #28
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What is the most restrictive section in the exhaust on bonnies.
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Old 02-12-2007, 09:23 PM   #29
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nope.
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Old 02-12-2007, 11:08 PM   #30
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What is the most restrictive section in the exhaust on bonnies.
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