hosrom_951

Fast951: "My race/development car takes all kind of beating (400-450+rwhp) and the internals are all stock."

Is this including the stock head??


V944god: "so how much power can we push on a stock block/internals using pump gas 93?"

After reading all this, and the project i was about to take ina few months from now (mind winter) i just asked myself the same question


Magown: Holly crap dude if that is whp and the engine is 'all stock' then let me in your secrets ALL OF YOU (unless if it's your 88 944 with the mods on your sig)

rage2

It depends on a few factors here, ie quality of fuel, condition of the motor (compression/leakdown), blowby, oil contamination in combustion chamber, etc. On 94 octane, I was able to make 350whp, at knock threshold and fairly conservative timing under boost. I've seen better numbers than that though.
Any turbo that can flow and supply fuel for that power level will do the trick. Properly matching the turbo for efficiency range you're running will help squeeze the last 5-10hp out of pump gas.
Uhh, there are no secrets. Big turbo, tuned with 24psi of boost with race gas will do that on any 951. And in case you were just misreading, we're talking about STOCK INTERNALS, the topic of this debate we're having here .

Duke

This discussion has gone haywire!
It seems we're discussing different things.

Rage I made the conclusion that a 28 psi 460 rwhp 2.5 liter M44/M5x engine would not very reliable racing the Nürburgring or German Autobahn based on what kind of spiced up machines that often break there.

I thought we were talking about pump gas here! Where talking about reliability of xxxxxx miles on the street, who the heck can afford lumping around town constantly on race gas?

Rage2 and Fast951 it looks like you are partly discussing how much this engines internals can take.
I'm a but surprised that you John (Fast951) agrees to this whole "28 psi is no problem"-discussion since you don't recommend anything higher than 15 psi on pump gas. So as I said, I think we're discussing different matters.

With that said, as soon as I get a new WG I'll turn up the boost to 20 psi in my car (it's a daily driver). If only the link box would support 25 psi I'd gladly install water injection and go for it (on pump gas). So don't take it as I'm afraid of boost

hosrom_951

Rage2: Yes Rage, that i didn't mis-read that's what got me into this post in the first place


As mentioned earlier on this post, now I ask this:


As long as the engine is tuned correctly (A/F ratio is set on/off boost levels), the engine would still be reliable since we are hitting high boost?

Besides the all important a/f ratios at such high boost, what else would 'damage' or decrease the liability of the engine? what else should be closely monitored?

rage2

I've never ran the Nurburgring, so I can't really comment there. I have run many long session roadcourse and drag events, and these motors can take a beating.
Just buy 'em in drums like I do!



Water/Alcohol injection can easily replace race gas, but really, that's not what I'm trying to argue here. I'm trying to debunk the myth that high boost is a bad thing. At least that's what I'm trying to do... . And yes we're starting to veer a bit off topic.
Yea, note "pump gas". Octane is a wonderful thing hehe.

rage2

Timing and EGT. Too much timing will detonate, break pistons and ringlands, snap rods. Too little timing will melt your exhaust valves and anything downstream of that. As revs and boost levels climb, the window between too much and too little timing decreases, so you have to be careful.

If you dunno how to tune it, get it done professionally.

hosrom_951

Rage: Thanks for the info........BTW looking over and over again at that barrel you have stashed there just cracks me up

Duke

Hehe wish I could afford it, a 200 liter barrel of Aspen Race fuel costs almost $700 in Sweden. That's about 2-3 weeks of driving for me

Dark Lightning

I've been promoting the big turbo, medium boost concept for a while now and mostly got laughed out of a Rennlist thread:

https://rennlist.com/forums/showthre...62#post1557962

I ran 26-28 psi daily on 8.5:1 and 93 octane. Don't say it won't work 'til your motor blows.

fast951

I never said to run 28psi, and I never said to go over 15psi on pump gas with the chips supplied with Vitesse Kits. All I said was the stock internals have held up to plenty of power...

To clarify something before it's taken out of context... DO NOT RUN MORE THAN 15PSI BOOST ON 93 OCTANE GAS WITH ANY VITESSE KIT!!!!

84black944

what about 94 octane

Dark Lightning

Ain't gonna save you. It helps a little but it's still not race gas. Everyone falls into three basic categories: there's Soviet Republik of Kalifornia 91 octane ****, 93/94 octane everywhere else, and 100+ octane in the nice blue 55 gallon drum.

streckfu's

So where do you buy your drums?

84black944

oh i almost forgot there is a gas station not rear far like 5 min from my house that sells 100 octane but for the steep price fo $4.00 a gallon

Dark Lightning

Be forewarned that most 100+ octane pumps have a larger nozzle than is normally found on passenger vehicles. You might have to bring a gas can, pump into the can, then pour into your car.

This might not be the case, but it's an issue I ran into previously.