What would be the ideal Compression ratio for a 383 part time nitrous motor with say 200 to 250 shot to boot. Longevity? Wear rate?

The 383 stroker that we are putting together this winter is going to be mostly street/strip and will only be sprayiing at the track so I want to get the most out of it NA and have the nitrous secondly.Im planning on using the TFS heads with a full P&P job, so hopefully around 300 CFM. What compression should we build it for?

-john

 

As far as I know Comperssion ratio dosent really matter just make sure your timing is correct for the shot that you will be using.

I know people that have 8 to 1 and also people that have 12 to 1 and either one has trouble with their N20 set up

 

I believe you will make more power on the bottle with a higher CR. Someone can correct me if i'm wrong. But if you want good power NA and still streetable on pump gas, I would go with 10 to 11:1.

Ken R. 95Z

 

84zpower: are u saying they both have trouble with nitrous? or no? i am planning on building a 12.5 or 13.5 to 1 compresion sbc with a big shot. compression shouldnt matter up to a point, aslong as you can keep everything sealed up and the cylinder heads on the car. i'll be running race gas, but dont think you cant drive a car like this on the street, you've just got a limited cruise range until you can find a pump with race gas. here in detroit, there are a few stations, so as long as u can get good gas, build it afew points higher, and get more power out of it on motor. just my .2 cents

 

Hi compression with N20 is fine as long as you pull the proper amount of timing and or run good enough fuel for the setup that you want.

 

Since you will be staying EFI ( I assume) then there is no reason to run any lower than 11:1, 12:1 is very possible too, with 93 octane and EFI. You don't pull any more timing with anymore compression. You just run the right gas. I wouldn't run a 200 shot or more without race gas.

FWIW I have 11:1 can run pump gas (carbed) and I have sprayed 300 with VP C16 and just pulling 8 degrees. Next step in gas would be VP's N2O gas. Pat Musi runs it in his motors and doesn't cost that much more than C16.

Also FWIW: ANY "pump" race gas is not as good as out of a drum. most of those station change over to Kerosene in the winter and put it in the same tanks.

Good luck
Dave Brown
Wheels Up Racing
http://www.fastrides.net/board/image...e893644c6f.jpg

 

mine is 11:1 and no forged pistons, running a dry kit jetted for 175 shot pulling no timing, and running on pump gas alone. just using 1 step colder spark plugs.

i know people say 2 degrees for every 50hp worth of juice, but if it doesn't detonate, the i dont see the need to abide by that rule of thumb?..