let's chat

[brett4]

There is a guy kicking ass in national Imca modified events changing carbs for the feature but not fuel ( stays on methanol) any ideas?? maybe just bigger carb is my guess to kill bottom end

[brad hibbard]

OMG---I have preached for years that carburetor size is a chassis tool not an engine thing

I believe you are 100% correct---this guy has a "small" snappy carb early in the night when traction is available but when things slick off he goes to a bigger carb to soften the bottom end power ---which acts like traction control and the bigger carb will build power after the flagstand once traction is available due to momentum
Sounds like your competitor has listend to my sermon--LOL

Brad
www.race-1.com

[ZERO25]

Brad, is there nothing to gain by changing the hole size and or shape of the spacer? Kinda like Wehrs Machine does with the intake inserts!

[brad hibbard]

I believe the Wehrs inserts are basically restrictor plates to calm the power down for better drivability in the slick.
but to answer your question more directly---YES there is absolutely gains to be made with hole designs and height of spacers.
In general it has been a give and take for HP against torque and/or low RPM against high RPM
The trick is to build on one side and not take so much from the other or to maintain the opposite.
For 604 engines on dirt with traditional carburetor (with floats) we typically always use the Crate Innovations 1001+ angled spacer https://race-1.com/i-23432925-cii-10...tegory:1028085
For pavement and superbowl carb applications we have a different version that we like

the carb spacers that use different inserts are very common in the open engine world where many times the given power is just not needed

the 604 spacer by wehrs that has a turtle going down inside the intake is beneficial but also not permitted by most crate sanction rules

Brad
www.race-1.com

[missile07]

Brad,

Is there any benefit in raising a flat air cleaner base higher on the carb with a spacer kit? Away from the engine, cooler air?

[Mopar DLM]

Has anyone ever done any testing with a shear plate on any dirt engines?

[brad hibbard]

Mopar DLM----I really am not sure what a shear plate is-----I look at them and in definition I think they are basically a restrictor plate ----but I am always willing to explore----help me understand a little more

Missel07----air cleaner height is an awesome topic -----given more time I will chime in with my testing and theoryies

Brad
www.race-1.com

[Mopar DLM]

What I know them by is a shear plate but it's probably better described as an anti reversion plate. Bolts under the carb to give it a little better signal and usually helps an engine with a carb that is a little to big. They are not designed to be a restriction. It gives a very sharp edge to help the incoming air merge with the pulses inside the plenum and help stop air from trying to flow back up inside the carb. Sorry guys i'm not sure I have given the best description of how they work.