At 09:07 AM 2/20/98 -0500, you wrote:
> I merely stated that a cat back 3" exhaust does not have enough
> backpressure and causes undesirable resonance with a stock motor with
> stock manifolds and cat.
Well, I got the Gibson 3" cat back and the difference between stock and this
setup is like NIGHT AND DAY! :->
As far as "undesireable resonance", I dont have any. The truck sounds WICKED!
>Changing my muffler merely removed the added
> restriction. Retaining 2.5" maintained correct backpressure to avoid
> resonance.
I understand your thinking here, but the muffler ALSO contributes to
back-pressure, actually probably is the biggest contributor.
The size of the pipe would control the size of the pulse and therefore the
speed at which the pulse moves.
> My results: (no power braking involved)
> Stock - floored of line - negligable tire spin
> K&N FABM - - about a 6 second smokey burnout
> Flowmaster - nothing but smoke well into second gear
> SG mod - about a 3-4 second burnout then traction
> Sounds to me like I improved horsepower then added traction.
> Comments?
> Joe Borg
You could definately have improved HP and then traction here. But, on the
other hand, it is kind of tough to measure HP gains by tire spin....I mean,
the amount of spin ya get is affected by so many factors that I dont know if
you can really judge gains accurately by it. Although I have no doubt that
you have greatly enhanced your HP output over stock.....
BTW, I have the Gibson 3" system with a Dynomax SS Racing muffler....
I think, overall, the various systems are all gonna be similar....The
differences will be the subtle differences in sound and minor HP gain
differences.....
>
>
>______________________________ Reply Separator
_________________________________
>Subject: Re: DML: Gibson exhaust installation
>Author: <dakota-truck@buffnet.net> at internet
>Date: 2/19/98 8:32 PM
>
>
>Joe,
>
>Flowmaster is trying to sell Flowmaster. What youwere told doesn't compute. If
>the Y
>pipe and Cat are the major restriction opening up the exhaust system after the
>cat
>would have negligible effect.
>
>I have a 94 Sport with the 5.2, 5spd, and 3.90 gears. I've had the truck since
>new
>and have had it to the track a few times. The most marked single
improvement was
>the
>Gibson cat back exhaust with a set of JBA shorty headers which use the
factory Y
>pipe. I picked up 2 mph at the strip and 2 mpg on the road with this
>modification.
>
>A few years ago CC did a 2.2 turbo package called the Super 60. The
development
>was
>done on a dyno and with mufflers and the Dynomax Ultra made 20HP more than the
>Flowmaster.
>
>KW
>
>Joe Borg wrote:
>
>> Jeff, I recently called flowmaster. They stated with minor mods, the
>> stock exhaust system is more than adequate when a flowmaster 2 chamber
>> muffler is installed. They stated 3" pipe does not have enough
>> backpressure and although sounding "meaner" woulsd actually slow you
>> down. The concept of single in dual out mufflers is pure show and no
>> go. An exhaust system can only be as efficient as its weakest point -
>> the 2 into 1 y pipe and cat. Unless you install 2 cats with a true
>> dual setup you are gaining nothing but sound and appearance. Joe Borg
>>
>> ______________________________ Reply Separator
>_________________________________
>> Subject: DML: Gibson exhaust installation
>> Author: <dakota-truck@buffnet.net> at internet
>> Date: 2/17/98 3:09 PM
>>
>> snip
>>
>> Does flowmaster make a similar kit?
>>
>> Thanks.
>>
>>
>> jeff
>> 98 RC 4x2 V8 5spd 3.55SG flares
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