Freestyle Jetting changes with PFP

[NVJAY775]

Hmmm. Good info. Matt and NV. I might grab some AV gas to be safe. I'm running 30 degrees advance and pulling back at 5500.

From what others have said AV gas isn't that great. Matt can explain it better than me, but you may be better off with something better. Cost sucks, but worth it. I'm a tight wad, so I run the sunoco 110.

 

[Matt_E]

AvGas is just a cheap octane booster. It has less energy content than pump gas. If you can run a motor on pump gas alone, do that. Once you mix AvGas in, you get less power.

 

[onlyFX-1]

That's pretty aggressive

What timing and compression you running matt? Mine is more aggressive than his. Let's just say I HAVE to run straight vp113. Out of all the fuels I've heard people running vp113 is the highest octane

 

[Matt_E]

I am at 185 psi cranking compression.
Here's the curve:

 

[onlyFX-1]

Throw some more compression at that mo fo, get you some more BRAP!

 

[Matt_E]

I'm going to 210-230 psi next year with race gas.

 

[onlyFX-1]

Oh yeah...that will add some good BRAP to it

 

[onlyFX-1]

I have a question a little off topic. What temps y'all running thru the whole PFP system? From what's hottest to coldest from engine to chamber to waterbox?
Anyone using some kinda waterjets in the waterline running to the chamber?
I'd think the best would be engine the coldest, chamber second hottest and waterbox the hottest. Also anyone running reverse cooling with water coming into the top of the head and out the manifold to the pissers?

 

[Matt_E]

I'm running regular cooling.
I run the pipe just cold enough to not burn the turf on the waterbox. That took some experimentation :lmao:

 

[onlyFX-1]

It is a lot of experimenting, I've been thru 7 battery straps to hold the water box down. My engine is warm, chamber cold and waterbox hot. I ran reverse cooling and a third cooling line to the chamber so I can tune the chamber more just don't know where to get jets for the cooling line.

 

[Matt_E]

Use Mikuni main jets.

I have adjustable restrictors on my engine cooling outlets to regulate engine temps. I run in 35-75 degree water, so it's needed.

 

[onlyFX-1]

Sorry I know it's off topic but I've been curious.
What are you gaining by restricting your cooling lines to your engine? Is it making it run hotter? Wouldn't it be ideal for your engine to be cold, making the combustion in the engine more intense?

 

[Matt_E]

It can be too cold for the cylinder and cause a cold seizure. I've had it happen. I restrict the outlets to slow coolant flow through the cylinder.

A cold engine doesn't gain you anything. You want the incoming air to be as cold as possible because the work performed by the engine is proportional to the temperature delta between incoming air and combustion temperature. (boring heat cycle/Karnaugh cycle stuff)

 

[onlyFX-1]

Yeah that makes sence

 

[Pablo]

From what others have said AV gas isn't that great. Matt can explain it better than me, but you may be better off with something better. Cost sucks, but worth it. I'm a tight wad, so I run the sunoco 110.

Is Sunoco not a decent high octane fuel? I was doing some reading but am fairly uninformed when it comes high grade fuels. Is VP a better option? I found Sunoco for roughly $10/gal in a drum. Seems plenty "high" grade to me!

 

[Matt_E]

There is more to race gas than octane. Oxygenation and lead content come to mind

 

[NVJAY775]

I've heard Sunoco is good, but isn't oxygenated and I'm not sure on lead content. Wish I could tell ya more lol! I would think vp 110 would be fine, but ask someone like Matt to be sure.

 

[geraban19]

Hijacking the thread.....

Which waterbox were you guys using when Bpiped????

Thanks

Gera

 

[NVJAY775]

Second gen xmetal.

 

[geraban19]

Second gen xmetal.

Thanks. I didn't know that it is not possible to run OEM RN SJ with big motors.