4-valve for torque and horsepower addicts

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Sep 6, 2007 | 05:24 PM

DesertBum

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4-valve for torque and horsepower addicts

I don't know if this has been posted before, but did a search and didn't see it...

http://www.rpmhemi.com/

[IMG]local://upfiles/10966/E2504D9B41354B7183ADAFE7CA7EEE80.jpg[/IMG]

Sep 6, 2007 | 06:19 PM

skullandcircle

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RE: 4-valve for torque and horsepower addicts

sure it has power, but you are going to have those two dudes following you asking "is that a hemi?"

Sep 7, 2007 | 06:03 AM

dog155

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From: Windham,Maine

RE: 4-valve for torque and horsepower addicts

Looking at the line graph tells me these are great flowing heads,as long as you are up in a rpm range I never use.If I were to build a drag bike those would certainly be on the list of parts.

Sep 7, 2007 | 07:16 AM

wisemx

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From: Johnson City TN U.S.A.

RE: 4-valve for torque and horsepower addicts

That same design but with solenoids instead of push rods and springs would be a dream.

Sep 7, 2007 | 08:13 AM

bobcowan

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From: Colorado Springs, CO

RE: 4-valve for torque and horsepower addicts

Pretty trick. I remember a while back one of the aftermarket companies was producing a bike with an engine like this. Can't remember their name, though. They were bought up by Bikers Dream, and then shelved.

Multiple valve heads have a huge advantage in a carbed engine. Lots of flow for big power numbers. But velocity stays high at lower rpm's for good street manners. You could use cam and compression to get the same peak numbers. But then your low rpm performance wouldn't be as good.

Sep 20, 2007 | 05:22 PM

wetwolf

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RE: 4-valve for torque and horsepower addicts

Actually, a 96ci 4 valve engine makles over 90 ft/lbs of torque starting at 2800 rpm all the way to 5400, and thats at the rear wheel. It makes over 100 ft/lbs of torque between 4000 and 5200. Thats a pretty healthy powerband. The aftermarket compnay that was using 4 valve heads would have been American Quantum.

Sep 20, 2007 | 05:31 PM

Cynic

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RE: 4-valve for torque and horsepower addicts

I think they were first developed by Jim Fueling. I don't know how much time he put into them, but it took theJapanese quite a while to get them right. The problem was they had lots of tumble but no swirl. BSFC, Brake Specific Fuel Consumptionwas really bad too, but as you know they finally got everything right. I don't see the port layout on them promoting much swirl.