Neal's a good guy. You'll have a good time talking with him. A wealth of knowledge.
Time to go Stage II!
- Thread starter Alky V6
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Like I said. All those simple calculators are screwy.
I'll put the car on a chassis dyno for you guys after I get the engine in. What sort of tire should I use? I know you can't use a slick, right?
should be some interesting info ?
Rob, I just put your timeslip & weight into the HP calculator Tony listed and it spit out "Your HP computed from your vehicle MPH is 789.64 rear wheel HP and 877.38 flywheel HP". We dynoed it at 768 rear wheel HP using 1 psi less boost. Based on the hp/psi gain we were seeing on your car this looks to be very accurate. I dynoed 802hp on a TSM car that went 152 which is real close to what that calculator has. I've seen it over and over where 600rwhp TR's will sneak into the 9's and 800 rwhp TR's will sneak into the 8's.
After putting Donny's weight/mph in the same calculator, it spit out "Your HP computed from your vehicle MPH is 857.05 rear wheel HP and 952.27 flywheel HP". This would be cosistant with what I have seen. Adding 400hp cylinder heads should put it over the HP Tony Gomes was making
Maybe I'm being too optimistic, I don't know. I really don't have any experience comparing actual dyno runs to timeslips. I do know one thing for sure. We will find out what sort of numbers she ends up putting out.
The Stage I project already blew the sim that I use out of the water, so I can't say that I trust the sim with the Stage II prediction, but it will be interesting to see how everything compares in the end.
Everyone has my guess. Who wants to add theirs?
Keep in mind, also, that the above calculator is only using 10% to account for drivetrain losses. That's low in my book. I agree with lazaris that 15% would be a minimum for an automatic transmission with a performance torque converter. 10% would be more like for manual transmission losses.
Keep in mind also, that the cars I sighted above were ALL automatics and their numbers were very close to that HP calculator.
Of course, using that calculator, you would need to change your signature from 5+ bhp/cid to 4+ bhp/cid. But them again, we went over that in your other thread months ago
Of course, using that calculator, you would need to change your signature from 5+ bhp/cid to 4+ bhp/cid. But them again, we went over that in your other thread months ago
Those calculaters are withing 12 HP of what my car made on the dyno.. Weight and MPH is pretty close most of the time..
I was going to include you too, Geno, but I couldn't remember the exact boost levels we hit on the dyno. Give me a call tomorrow morning.
31# made 1050 RWHP car weight 2540 with me in it..
So you're agreeing with the 10% drivetrain loss? Have you pretty much come to the conclusion that 10% is a good number, even with automatics?
So if you blew the sim away on the stage 1..... and the sim says 1500 + on the stage 2 what do you think the stage 2 will make for rwhp.... ?
I'm not agreeing with that at all. I'm just saying the calculated rwhp value is close to what I have seen on the dyno. I would have to dig out some old engine dyno sheets, before I could make any assumptions on that calculated flywheel hp. I haven't had a Buick on an engine dyno in over 5 years. Most of the cars I dyno tune are using PTC convertors which seem to couple quite well, so I may have skewed data
I have dynoed cars with all sorts of tires. I would recommend an old tire since the dyno eats them up pretty well. If the car is strapped down correctly traction won't be an issue. You may want to talk with Billy T, he just had a tire blow out on the dyno and it damaged his car pretty good. He has done quite a bit of homework since then
I'm not even going to guess on that. We'll just have to wait and see what we see.
The sims that I deal with use bhp. The TC I've been presently using is slipping about 12-13 percent by the finish line, according to that best E.T. run at Firebird. And that was with the engine leaning. TC slippage may have been even higher if the proper fueling had been there.
With that high amount of TC slippage, I'm assuming my drivetrain losses were quite a bit higher than the universally accepted minimum of 15% for an auto trans. Unfortunately, I have no data that I can use to change that assumption.
lazaris likes a range of 15-22% for drivetrain losses with an auto trans. With the amount of TC slippage I'm seeing, let's assume I have 22% drivetrain losses.
The calculator that Cal prefers is showing my rwhp to be 857. Let's say that figure is off by 12 hp, which is what Gene has seen. That would be 869 rwhp. If we use lazaris' max of 22% for drivetrain loss we have;
869/.78=1114.10 bhp.
1114.10/224 cid=4.97 bhp/ci.
If we use 23% for drivetrain losses we have;
869/.77=1128 bhp.
1128/224 cid =5.03 bhp/ci.
I think I'm pretty close on that bhp figure. Close enough for government work, anyway.
The calculator that Cal prefers is showing my rwhp to be 857. Let's say that figure is off by 12 hp, which is what Gene has seen. That would be 869 rwhp. If we use lazaris' max of 22% for drivetrain loss we have;
869/.78=1114.10 bhp.
1114.10/224 cid=4.97 bhp/ci.
If we use 23% for drivetrain losses we have;
869/.77=1128 bhp.
1128/224 cid =5.03 bhp/ci.
I think I'm pretty close on that bhp figure. Close enough for government work, anyway.
If we take Cal's calculator figure of 857, and use Tony's estimation of that figure being 5% off, we get 902 rwhp. Using lazaris' 22% for drivetrain loss we get;
902/.78=1156.41 bhp.
1156.41/224 cid=5.16 bhp/ci.
That's using the figures that you guys came up with.
For quite awhile now, I have been maintaining that my bhp estimation for the Stage I engine was 1,130. So, where am I going wrong with my figures and math???
902/.78=1156.41 bhp.
1156.41/224 cid=5.16 bhp/ci.
That's using the figures that you guys came up with.
For quite awhile now, I have been maintaining that my bhp estimation for the Stage I engine was 1,130. So, where am I going wrong with my figures and math???
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