cutting out the runner divider...
any benefit?
little more volume?
anyone done it?

some TPI setups seem to benefit from it.....would the LT1?
wouldnt be hard too do! would make porting a bit easier

 

Cutting out what? The space between the Intake ports?

 

yes

 

That's an interesting idea! It seems like you wouldn't want to take out the whole divider, but I wonder how much of it would be optimal (if it would show a gain) to take out. This would be a good advanced tech topic, in my opinion.

 

do it and tell me how it works out

 

what part of the divider being left in would be beneficial, at the beginning of the runner (entry) or end of the runner (exit)? and why?

 

I really have no idea. Most of the ideas I've heard for improving the LT1 intake involve adding more volume to the plenum.

If you took out the whole divider wouldn't you have cylinders fighting eachother for air? With the runner you are simply setting aside more of a volume of air for whenever the cylinder draws it in right?

 

the cylinders that would be siamesed, wont be the ones firing at the same time or firing in sequence...

with the divider completely removed, a gain in volume would be there but how much and is it worth it...?

it seems like only the runners on the back side of the divider would gain from the removal tho since there wouldnt be any change too the intake for the cylinders that are on the front side of the divider....altho the added room with the divider removed might aid in porting of that area for those cylinders...??

 

Keep in mind that a gain in volume takes away from velocity of airflow, holding all things else equal. I'm not necesarily talking about plenum volum, but you're turning two runners into one, and I'm honestly not sure how they'll react. I have seen siamesed runners for the TPI like you were talking about, but that's a vastly different set up to start out with.

 

and thats why i'm hoping some of the more experienced fellas will chime in and shoot down any hope i had of this gaining anything at all

 

My thoughts exactly. By removing the majority of the divider would that not cause a whole lot of turbulance at the intake/head transition point?

I would think that the amount of divider you would need to keep to provide velocity and smooth airflow would negate any gains in the first place.

 

any other takers on this?
Rich, Fred, Bret, Phil, Joe, Mindgame....?

 

i have heard of this...my one buddy did it to his car...if your looking to get your fuel mileage, i wouldnt do it, but for an easy HP mod...its a good idea..

 

Let's try copying this to Advanced Tech and see what kind of a response it gets.

 

It would kill everything. The intake system needs to be optimized to match the cam profile. For low RPM engines, long, small diameter runners will cause the maximum port velocity, and thus the most intake inertia. These long small runners will become more and more restrictive as the RPM increases since the airflow will increase with RPM. Therefore, a midrange RPM manifold will have shorter but larger diameter runners. As the RPM goes up, the port diameter can increase to keep the optimum port velocity. Once you get really high RPM, restriction becomes the biggest problem. At this point, you generally need a short, large diameter port. For multiple cylinder engines, and low to mid RPM range performance, you can further optimize the intake system by combining runners. This will let some of the inertia from one cylinder be used by another. Runners can be combined into one final plenum which can also enhance intake inertia. If you look at high rpm, small displacement engines from the 50's and 60's they often had short, individual runners with a carb barrel for each cylinder (a classic example is a Ferrari V-12 with 6x2bbl. Webers). Look at the intakes used on high rpm drag motors (eg. a tunnel ram). They use short runners and a large plenum. But each cylinder still has an individual runner to provide a harmonic ram effect at high rpm.

Rich