Hey guys,

I am running a 355 with 7.7 to 1 compression all 4340, o-ringed, splayed, and basically ready to push over the 1000 hp mark.

I originally built this engine with plans of boost levels over 20 psi on pump gas, however at this point I don't want to upgrade to an f-1 so I picked up an nos Nosszles direct port system to run in tandem with the 15# intercooled D1-SC.

I am obviously planning on creeping up on my numbers, and between my dynojet and the F.A.S.T managment I know that tuning will not be a problem.

What I would like to throw up in the air for discussion is what the limitations of this engine are in terms of cylinder pressure from the boost/N20 combonation.

There are a lot of people succesfully running 150 shots on top of boosted applications, but because of my ultra low compression, I was tossing the idea around of the boost combined with a 250 shot.

As I said previously this is not a shot in the dark proccess, I will be taking all precautions on the way up the boost ladder, I am however just curious what your theories are, and why.

Thanks,

Martin

 

As I'm sure you know, there is no absolute limit. The equation has a number of variables, primarily how strong the parts are, how much stress you put on them and [/b]how long[/b] you want them to last. IOW, assuming a careful tune and assembly with good parts you will not immediately blow up your motor with a 250hp shot v. a 150, but it will simply not last as long. These kinds of combos are a relatively new concept. I don't believe that the data exists to give a real definite answer.

You weren't specific about what parts you are using. "All 4340" encompasses a pretty wide range. But my own "rules of thumb" indicate that ~1,000hp is do-able with "reasonable" longevity assuming street/strip use. I would never run even the 150hp shot on top of 15psi on pump gas and I would strongly advise water/methanol injection in addition to high octane fuel to avoid detonation. I use 104 octane unleaded at the track with my 17psi+200hp shot combo and I also have water/methanol injection. My friend Bob Kennedy makes the water injection system, you can see it at www.kennedysdynotune.com

Rich Krause

 

Rich,

That is the kind of experience I was looking for, I just wanted to see how far people are pushing the envelope on dual power adders. My plans involved a straight draw of C-16 for the nitrous system only, and pump premium only for the main system.

The pump gas is basically the line I have drawn in the sand for this car, once the need for higher fuels arrives that is when I am shutting this project down.

The water/methanol injection looks promising so I may pick up a system to play with, but it looks like if octane will become an issue that I will just stick with the 150 shot which shouldn't need it.

Cheers,

Martin

 

rskrause: just out of curriousity why do you run water injection rather than alky or methanol?? or do you run that through the water system?

just currious