Carb spacer height

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rdkonkel
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Carb spacer height

Post by rdkonkel » Mon Feb 12, 2018 8:54 pm

Limited chevy 355 9.5:1
Edelbrock 2701 intake
Holley 750
6800 rpm limit
No rule on spacer.
Have ran without one, and with a hvh 1”
Question: would we benefit from going to a 2” spacer?

ProPower engines
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Re: Carb spacer height

Post by ProPower engines » Mon Feb 12, 2018 11:48 pm

Depends on the application. My guess is oval track of some kind. But if so at what RPM does the car exit the slowest corner.
the reason I ask is adding more spacer just increases the plenum volume but a properly contoured spacer tailored to the application will improve thing drastically.

You did not mention if the intake was allowed to be ported internally since it is just a dual plane the extra volume may raise the rpm range some but to what point who knows without more data.................
Real Race Cars Don't Have Doors

rdkonkel
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Re: Carb spacer height

Post by rdkonkel » Tue Feb 13, 2018 2:06 am

Thanks pro power,
We enter the corner at 6600/6800 and not sure at what rpm we leave. This is dirt track class. No intake porting allowed.

rdkonkel
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Re: Carb spacer height

Post by rdkonkel » Thu Feb 15, 2018 8:43 am

Main question is will the 2” spacer help or hurt bs a 1” spacer?
I’m thinking 4500/5000 is the lowest rpm we have in the corner.
But on restarts will be in final drive gear.

Geoff2
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Re: Carb spacer height

Post by Geoff2 » Fri Feb 16, 2018 4:30 am

Just be careful of BS claims. Such as one forum that claimed a 1" spacer added 102 HP!! If it was true, it would be Summit's hottest selling item!!

I can see the ad now...'Add 100 HP in 10 minutes'. LOL.

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Re: Carb spacer height

Post by ZIGGY » Fri Feb 16, 2018 8:26 am

I doubt it will help, but two words: Try it. Don't be afraid to try spacer combinations as well.

RCJ
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Re: Carb spacer height

Post by RCJ » Fri Feb 16, 2018 10:38 am

It would be hard judge if a spacer helped or not on the track.It will often times change the fuel curve and afr. If you can't measure and make adjustments you have know way of knowing if it helps or not.If I thought I needed more at the top of the rpm band I would try a 2'' open,I have also had good luck with a 1'' super sucker on top of a 1'' open.

rdkonkel
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Re: Carb spacer height

Post by rdkonkel » Sat Feb 17, 2018 10:40 am

The hvh 1” on top of the open 1” is actually what I’m thinking.

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