Be careful, I didn't say that was optimum, I just said below that is where things start to get shaky. Obviously we would like to make to most power on the least amount of PSI possible.

The big point is that there seems to be a correlation, but it's important to remember that correlation is not causation!

I think we need to look more at the torque numbers down low from everyone's dyno sheets; maybe we can pick a sample RPM and gather some numbers to analyze from there. FI gurus please chime in and feel free to throw BS flags as required!

 

Got data? I like this thread

 

I want to point out an observation. These cars are NOT making 42hp per lb of boost. You have to have a baseline of the n/a engine and then you only count the horsepower you GAIN above that to determine how much hp per lb of boost you get.

Obviously if you only use 1lb of boost and you're gettin 273hp then you're saying you are getting 273 hp per 1lb of boost. wow....definitely not how it's calculated.

 

Great Point. I was wondering how everyone was coming it with 4Xhp at XXpsi. I was saying to myself, "I need to get the kit they are running".

 

ya, give or take 20hp per 1psi is good. I think some people have gotten 22hp per 1psi and that's a great hp gain.

Mine was putting down about 20hp per 1psi on the DD dyno.

 

22whp/psi here, dynojet

I wanna know how someone can get 4x/psi?? church's dyno?

 

ya, 22hp/psi on a DJ would be right in line with 20hp/psi on a DD. Good hp/psi.

40hp/psi comes from the magical dyno. You need to climb the beanstock to get to the dyno though...

 

very good point sir

 

So from everything I heard, peak TQ is the stock VQ killer.

Do you really think it's just the TQ alone, or is it detonation at those levels given pump gas + stock compression + so-so tune?

 

I think the stock rods are just crap and were taking this way to seriously. The engine is only as stong as the weakest link...and the rods are crap combined with the high compresion.

I would really like to just see someone lower the compression of the motor without changing a single part and then boost the crap out of the motor. I bet it would hold up fine.

 

I've been tempted to just swap out the rods and keep the oem pistons. Don't here too many of those going bad.

 

ya, sad thing is when you have it torn down you might as well put better pistons in it so the engine is fresh. It's a violent cycle since the engine is open you save time and money just doing it all. That's why nobody has experimented with it.

 

Yeah, but I'm not one to really care if I have to tear it down again. I do these kind of things for fun and thankfully I've had pretty darn good luck...lol. I dunno...maybe I'll just get everything in one shot....but I may just stick with the rods alone....just because I can.

 

The figure used for HP/PSI is not literal. I figured everybody understood that already. It's the ratio that matters; we simply don't have enough data to subtract 250 (or whatever the baseline is) from everybody's numbers. If we did I suspect the ranking will stay nearly the same. The significant numbers we have to work with are total horsepower, peak torque, mileage, type and PSI. I'd love to have mid-range torque numbers and baselines, but that's about 169 more data points that will be hard to get.

 

Excellent thread majestik. In my opinion part reason why turbo setups are more prone to have problems is not only because of torque, but because of how they are tuned at those higher torque numbers (compared to SC). More torque usually requires a good ear for knock, and good timing, there is alot of good tuners out there, but there are also alot of not so good tuners that dont pay 100% attention to some things. I personally think its the tune that causes issues and not the boost (well upto a point ofcourse).

 

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