Topic: Supercharged CB750 engine

[speedracer741]

A friend sent me this picture of an 836 alcohol injected engine fitted with a GMC 350 blower running 45 psi! It was run back in 1973 in a top fuel dragster.

[medic09]

 

[scondon]

Damn, I think I just heard my engine explode    How long can you run something like that before it melts?

[mrblasty]

Damn, I think I just heard my engine explode    How long can you run something like that before it melts?

Three seconds, man that thing would be scary rattling between the knees.

[jonbuoy]

That blowers bigger than the engine, drag bike?

[cben750f0]

DAAAAAYUMMMM!!!!  man i want one... dont care how,where or ..... how...... but must have...... would be a quick trip to the shops for milk!!!!!


peace

[CrisPDuk]

Damn, I think I just heard my engine explode    How long can you run something like that before it melts?

Just guessing, but probably about 5 seconds longer than it takes to get it to cover 0.25 miles?

[burmashave]

Did he put all that stress on the stock transmission?

[Geeto67]

looks like an old sportsman class rail dragster. Really they used to run anything in there and there were divisions for motorcycle powered rails. On alcohol (which runs a lot cooler than gasoline) it would not surprise me if that engine lasted more than just a few rounds. Personally at 45 psi (are you sure he did not say 4 to 5 psi) I figure you have to do head gaskets after every other pass (unless you oringed the block) but other than that it should have held up fine. The blower drag on that motor must be insane.

[speedracer741]

looks like an old sportsman class rail dragster. Really they used to run anything in there and there were divisions for motorcycle powered rails. On alcohol (which runs a lot cooler than gasoline) it would not surprise me if that engine lasted more than just a few rounds. Personally at 45 psi (are you sure he did not say 4 to 5 psi) I figure you have to do head gaskets after every other pass (unless you oringed the block) but other than that it should have held up fine. The blower drag on that motor must be insane.

You are correct! This was in a rail dragster. The builder and owner of the car has confirmed that it really was 45 psi. Here is a current picture of the car:

[CrisPDuk]

45psi, thats roughly 3.5 Bar

He's bravr than me if he sat with that thing screaming it's nuts off inches from his head

[MRieck]

 Turbo funnybikes run 50 to 60lbs of boost.

[chung]

It's good for big woodies but what can we use for fuel on the street? All this crap on TV about saving the planet.... in California, I spent almost a year with a 5gal can looking for M85. Not a single 'green" station had the fuel. One store owner told me that he removed the pump because he had the store 3 years and never sold a gal.

Maybe BP and SHELL will buy some farmland in Kansas so we can get some 110 octane Ethonal at the pump before my balls shrivel so small that I can't use it for anything but cocktails

And don't delude yourself, if the oil companies aren't involved, we won't get it.

[mwohlenhaus]

by the looks of the tranny cover, I am guessing that it is not stock.

[Heironymous Josh]

I have a friend that builds custom CB's and he rode a blown 836 running about half that pressure (21 psi) and it only lasted about a year.  The motor was completely rebuilt and rebuilt well before the blower was installed.  He typically ran 91 octane in it or 103 when he got the chance (we have a local gas station in the middle of the burbs that sells race fuel).  Long story short:  SOHC4 + Boost = Blown Motor.

[Andoo]

Off the drag strip you don’t need boost. On the street it's all about Psychological Warfare.

This is called the Jay Leno effect.

[super pasty white guy]

Ok, maybe it's just my inner 12 year old coming out, but this was the funniest thing I've read in awhile.

"He's bravr than me if he sat with that thing screaming it's nuts off inches from his head"

Thanks for that.

Dave

[scunny]

back when I was draggimg my sorry arse down the 1/4 a guy was running a CB350 twin with a supercharger on it, went pretty good too apart from the odd blown motor when he managed to force to much methanol in to the motor. the blower was from an aircraft cabin pressurisation unit.