first of all, i'm just asking because i'm confused; i'm not trying to start anything.

random, you said that at about 8psi, you would expect about 200hp. cnk emailed me and said his kit makes 280-300 hp at 7-8 psi. how is this possible? you made the statement i'm referring to in a previous post about a turbo kit on ebay.

 

#1 Tuning. Improper Tuning can easily loose you 100 HP. I do think that 300 WHP on 8-9 psi is a tad high, but given a perfect setup, it's within the realm of physical possibility

#2. Air flow/Pressure and density (think efficency). Where are you measuring that 8-9 PSI? At the intake manifold, or at the comressor outlet? After the Intercooler? Or before it? What temp is that air as it enters the Throttle body (easy place to measure temp)? What was the temp of the air that went into the compressor? How efficent is the intercooler at cooling (Density)? How big of a pressure drop is there across the intercooler(IC Efficency)? How big of a pressure drop do you have due to your piping?

8-9 psi as measured at the compressor outlet is much different than 8-9 psi as measured in the intake manifold. 8-9 PSI at the compressor will probably net you 7-8 PSI at the Intake manifold on a well designed system, or as little as 4-5 at the intake manifold in a poorly designed system. To get that poorly designed system up to 8-9 PSI at the intake manifold, it might take 12-14 psi at the compressor.

8-9 PSI at 120F intake temp(Measured at TB) is much different that 8-9 PSI at 200+F intake air temp(measured at TB). An efficent turbo, and an efficent intercooler show great rewards.

#3. Compression Ratio
What is the CR of the engine? What is the shape of the pistions? We all know a 12:1 CR engine will make more power than an identical engine with a 7:1 Compression ratio. Turbo engines are somewhat the same, but not as severe. a 9.5:1 or 10:1 CR turbo engine might do great at low boost power, and put out big dyno numbers at under 10psi, but add in 15-20 PSI, and that same motor turns into shrapnel. Now take a low compresstion 7.5:1 or 8:1 motor, it only shows moderate gains at under 10psi, but it keeps performing well up into the 20's and 30's PSI.

#4. Timing (Valve and Ignition)
What valve timing was used? (who's cams and what are the specs of the grinds?) What ignition timing was used? (was timing retarded, if so how much) What engine managment system was used? (refer to #1)

#5. What grade of gas was used? 98 Octane, or 87 Octane or ??? To what extent was the tuning of the ECU tailored for High Octane gas?

#6. Where's the dyno? What kind of Dyno was it? Are these "wheel" HP figures, or extrapolated guestimates of "crank" HP?

[ January 04, 2003, 01:31 AM: Message edited by: Random ]

 

that's why i asked. i haven't read THE book, yet. i didn't know that you couldn't measure psi at different locations and get different readings. when i posted, i completely forgot whether or not the measurements were taken at the wheels or crank. duh thanks!!!