How much rpm can be gained by siamesing superram runners. Has anyone seen an rpm increase by siamesing just the runners. Seems like it would shorten the runner length. Stock is 21 inches total length. If you have done it what would be the safe limit and how difficult was it to do?

 

Ive never tried it, but i was considering it at one time. I was following a thread on corvette forum a few years back about doing this. Dont remember the guys name. But i believe he went little slower in the 1/4 after doing this.

Not sure if it was the runners or base that he worked on.

 

i would have to believe the effect would be the same as on the siamesed TPI runners like SLP, and AS&M semi-siamesed. Those were PROVEN to increase hp rpm potential as it does cut down the effective runner length to favor more topend.

Superram is already a cut down runner version of TPI for more rpms, how much more are you looking to get? I have heard the superram should beable to support a 350 to 5800 rpms with the right cam and heads? Biggest problem is flow of the base which is being dicussed (and has been discussed) in other threads

 

You would want to do it for wave tuning. In this case the 3rd harmonic wave. Where do you want peak power to come in? Lets say 5800rpm? You want a cam and induction system to coincide at that point.

I have tried to do that on my combination but somehow it has not worked out quite how I thought it would. Maybe this time around. For the 3rd harmonic wave to work in the 5800rpm range you need an induction runner length in the neighborhood of 13.5 inches or so. Varies depending on the formula used. I have used Pipemax. This includes the head, the intake manifold and the runners.

I believe the Super Ram runners are around 5 inches in length. So you would probably have to siamese part of the runner depending on where you want the 3rd wave to come in. Longer the runners the lower in the rpm the wave will come in. The shorter the runners the higher in the rpm band the wave will come in.

 

I would love to see the results of this. I just dont want to cut up mine to find out if it works or not. When LPE built all those 400+ cube motors wonder what kinda porting they did to there SuperRams.

 

That was exactly my thoughts. Most dyno articles point out porting was done but never actually get into what exactly was done.

Says modified superram intake.

http://www.goingfaster.com/spo/superram.html

 

Thats interesting never seen that page before. I bet the extra porting was done on the base. In Johns book he states that he built a 420 roller cam motor. That cranked out 525 horsepower at 5500 and 540 lbs-ft of torque at 4500. That porting was done to the heads, and intake base, RUNNERS and plenum. To get this kinda power and rpm. Doesnt say if they siamesed anything though.

I can tell you my 406 even with the porting ive done so far. Isnt peaking at 5500,so what did he do?

My cam is small buy some peoples standards. But ive run carbed 400s in the past. And the TPI style intake is more of a problem when it comes to rpm then the cam.

I just dont want to loose alot of power below 4000 to pickup power in the 5000/5500 range. But end up going no faster. I dont want to rev this thing much past 5500.

I did some searching on corvetteforum.com the guys name is ralph that siamesed the superram. Lost power everywhere and welded the material back in. Just one person results so take it for what its worth. Oh was a 350 so a larger 383-406 might see some better results.

Seems like the superram works well with large cams. Just not much over 5300 rpm but makes alot a power in this low rpm band. Compared to other intakes.