Did you dyno your car with the 12 psi water/meth combo? I don't know what you and your car weigh, but if you ran 148 in the 1/4 wouldn't you have to have been making 850-900 rwhp? I can't wait to see how effective Sean's intercooler is and how much more the Roe owners can turn up the boost.
I have not dynoed my car with the 12psi pulley with water/methanol. I did dyno the car in texas with the 9lb pulley and the water/meth but my results were within 5HP of my best SAE corrected number. The biggest problem was the a/f during that run, it was below 10:1 from 2500-5200rpm so I really don't know what it could have done with a good a/f. I really don't care too much about dyno numbers but they are important and if I thought I could put a sufficient load on my engine to simulate street driving I would consider dynoing again. I don't think any dyno would show me having 850rwhp but I do think I have that much torque.
I weigh 195lbs and my car weighs approximately 3400lbs with fuel.
Seans intercooler should be good but water/methanol will give more boost. The intercooler is going to be a great setup with a 10-12psi pulley for everyday driving but the water/meth is much better for drag racing, IMHO. The maximum pulley you can run without any intercooling is 10psi. The only problem with the intercooler is that you will probably lose boost, so when you put the 12psi pulley on you might only have 11psi but the intake temps are dramatically reduced. However, the water/methanol will gain you a 1 lb of boost and reduce your intake temps more than the intercooler.
I believe that most people will buy the intercooler and not mess with water injection. This will be a great route to go but I think water/meth will give better track results.
Just as a theoretical question about the Roe blower's capabilities: Without regard to how much psi the cylinders could accept, what's the most boost a Roe s/c could run?
The pulleys look small already, so there seems to be a limit due to pulley size.
Unless of course you went thru and changed all the engine pulleys (maybe just the crank pulley?) to overdrive the pulleys more.
I'd also be interested to know how much HP it takes to drive the blower faster to go from say 5psi to 6.5psi, or 8psi or more. Probably not much I guess.
- Just something I have in mind [img]/images/graemlins/smiles[/img]
Thanks utah. FE, I don't think it's a question of how much boost it can run because that would depend on whether the car has ported heads v. stock etc. It's more a question of how much air it can move efficiently without either creating so much heat even an intercooler can't reduce it enough, or overspinning the blower to the point it is no longer moving much more air or experiences mechanical failure. I don't think anyone has reached the upper limits yet. If you look at what the '03 Cobra guys are doing with the 2.2 liter Autorotor, many of them are making over 20 psi and over 700 rwhp with stock engines. And now Kenne Bell is selling a 2.4l kit (the same size blower as the Roe, although not necessarily the same exact blower) for the Cobra which KB says is good for up to 30 psi. On the pulleys, I think utah said before that at 12 psi (with ported heads) the blower pulley was about as small as it could be, but I don't see any reason one couldn't find a larger crank pulley or have one made. That's another thing the Cobra guys are doing. I will be very interested to see how far we can push this blower once the intercooler comes out.
I think it is limited to the 12 or 14 psi pulley. Not sure if that is due to blower speed or what. We know actual boost is based on engine effecency so it's better to relate this question to smallest pulley size and then relate that to boost on the engine in question. Utah can clarify/correct me here.
My "guess" on the hp loss would be: It takes more than twice the hp to go from the 5 psi pulley to the 10 psi pulley.......but then again, it may not have to spin that much faster to make that last 5 psi due to restriction of air flow in the engine. Good question, I looked on KenneBells web site and couldn't find an answer.
Just wondering...there are small and simple devices (14"long x 2" dia or so) with no moving parts that can take supplied pressurized air and create cold air. Supply pressures of: 20psi for a 60degree drop, 40psi for a 88 deg drop,60psi for a 104 deg drop and so on.
Sooo, if the Roe s/c could generate 20-25psi and you bled off 20psi to produce the cold air, leaving 5psi for the engine, you could almost have a built in intercooler.
The supplied air temp is the key. The s/c supplies heated air of course, but once the system got fired up feeding cooled air in the supply air, temps would drop...
Maybe in a continuing downward temperature spiral!!??
Or is that like perpetual motion? [img]/images/graemlins/smiles[/img]
That's like perpetual motion that takes more power to turn than you are getting back from the boost, ie: I bet it takes more power to turn the blower generating 25 psi than the 5 psi makes you in return.
I think the turbos are as close as you get to "free" hp.
Utah, I ran 3,600 lbs and 148 mph through two different hp calculators and both said 911 rwhp, so you may be selling yourself short. I agree the torque curve may make up for a total hp somewhat lower than that, but I have to believe you were around 850 rwhp anyway. Amazing. I predict that once the intercooler comes out the hp gap between some of the Roe cars and the high hp centrifugal cars is going to close significantly.
The blower can spin at 16-17k rpm for extended periods of time without failure. THis is a 2.5" pulley that usually produces around 10psi. The fastest the blower is capable of running for short periods of time @6000rpm is 19,500ish, sean could tell you exactly what it is. My pulley should make around 14psi but it only makes around 13psi because I think I have belt slippage. My pulley spins the blower at 18,260 rpm.
Basically you couldn't run a flat out silver state classic at 6000rpm with my current setup and have the blower live but you could easily run a one mile shootout without a problem. Usually you do not run a silver state classic at 6000rpm the entire time and I would not do it with my current setup but I would with a 10lb pulley setup.
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