Siamesed runner Q
09-24-2005 | 08:56 AM
#1
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From: SW Michigan
Car: '88 G T/A
Engine: L98
Transmission: 700R4
Axle/Gears: 3.27 9 Bolt
Siamesed runner Q
If I switch from my stock tubes to a fully siamesed runner (all the way through) about how many RPMs will it shift my power band up? I think I will try to go for a 1/4 to 1/2 way siamesed tube... I dont want to lose all my low and midrange torque.. its fun.
Last edited by MattODoom; 09-24-2005 at 10:39 AM.
09-24-2005 | 10:41 AM
#2
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Car: 1987 IROC-Z Camaro
Engine: 5.7 350 TPI - SLP Runners, AFPR, MSD Goodies
Transmission: 700R4 - Shift Kit, Corvette Servo
Axle/Gears: BW 9 bolt, 3.27s
Even the smallest amount of porting can help. If you don't siamese the base, i would say it would give you another 100 rpm peak gain, maybe 200. If you match the base as well, it wouldn't be unrealistic to get 300-400.
09-26-2005 | 11:57 AM
#3
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From: Ontario, Canada
Car: 1989 IROC-Z
Engine: 5.7L EFI LTR setup
Transmission: T-5 World Class
I have an edlebrock base and runners . The runners are opened up and siamesed in 4inches. click my www at the bottom to see. I also have a dyno graph there to show you the power curve. I still only make peak power really low . It's still a dog after 5000 rpm . But I did pout in a different cam ( ZZ4) so maybe a stock cam woulda faired better.
09-26-2005 | 06:09 PM
#4
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
I'm running SLP runners with one set fulley siamesed and the other almost. Here is my dyno graph with 212 degree cam.
Last edited by 1989GTATransAm; 09-28-2005 at 08:11 PM.
09-26-2005 | 08:37 PM
#7
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From: Cypress, California
Car: 1989 GTA
Engine: 369 TPI
Transmission: 4L60E
Axle/Gears: 3.70 Nine Bolt
I had a piece welded between the two pairs off runners. Then I hogged that part out. Here is a view of the backside.
I haven't lost any low end power. My car still burns the tires all the way through first gear and into 2nd. In fact I can go along at 45mph and mash the gas pedal and it will break the tires loose and start to go sideways a little. I would still like to loose a little low end power. I would get off the line better.
I haven't lost any low end power. My car still burns the tires all the way through first gear and into 2nd. In fact I can go along at 45mph and mash the gas pedal and it will break the tires loose and start to go sideways a little. I would still like to loose a little low end power. I would get off the line better.
Last edited by 1989GTATransAm; 09-26-2005 at 08:41 PM.
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09-26-2005 | 08:42 PM
#8
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From: SW Michigan
Car: '88 G T/A
Engine: L98
Transmission: 700R4
Axle/Gears: 3.27 9 Bolt
If you were able to grind the wall out all the way through even in the middle of the C shape then wow, i thought you had to cut them in half to get at that. Very nice job.
09-28-2005 | 03:55 PM
#9
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From: Ontario, Canada
Car: 1989 IROC-Z
Engine: 5.7L EFI LTR setup
Transmission: T-5 World Class
I noticed no loss down low aswell . My setup is a bit tamer than
1989GTATransAm but it seasm we got our intakes to roughly breath to the same points. 4900ish rpm seesm to be close to the new MAX of it. My runners were ported in 4"and siamesed no the top part only .
Here is MY graph with the setup in my sig . Stock 305 tune on the new 350 .
1989GTATransAm but it seasm we got our intakes to roughly breath to the same points. 4900ish rpm seesm to be close to the new MAX of it. My runners were ported in 4"and siamesed no the top part only .
Here is MY graph with the setup in my sig . Stock 305 tune on the new 350 .
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