I don't have his at all, and mine's not scanned.

 

What does the 228.4 represent?

When I plug in my #'s I get 485.33 net hp

 

I just use one of the eleventy billion online calculators, not sure what formula they are using compared to the one i posted. Looks like that formula I posted is quite off compared to the online calculators i've used.

http://www.geocities.com/MotorCity/4601/hpcalc.html
This one shows 450 hp on your numbers and 650 HP for my car.

So which one is accurate for my car? The 650 rwhp from the calculator or the 470 from the dyno? Somewhere there is a 180 RWHP difference. Both can't be correct.

I'd still like to know the exact reason that the HP readings are so different when comparing a manual car to an unlocked up converter. I've never seen an explination that looks valid to me. If it doesn't put it down on the dyno how can it put it down on the street or the track?

I also have the great spread sheet that estimates 1/4 mile times and MPH based off of average hp mustang dyno numbers and it has been very close with my car. If I use the mustang numbers from a manual car it's not even realistic compared to what that car actually does at the track. Another great mystery.

I'm beginning to think HP ratings are a lot like amplifier wattage ratings.. All BS.

 

This is my favorite by far:

http://www.stealth316.com/2-calc-hp-et-mph.htm

The guy actually compiled data from R&T from 162 cars and did a curve fit. His formula is called the LRT (Lucius Road and Track).

For my car, I get:

1064 hp (LRT)
911 hp (Hale)
959 hp (Fox)

Mine only makes 700ish rwhp with my A3.

Mike

 

the 470hp from the dyno is correct. The 1/4 mile calculators can't add in for time to shift,clutch slippage,clutch feathering time in a drag sim accurately but id be willing to bet added up those things are gigantic unless you running a pnumatically proshifted manual trans with a slipper clutch then you see alot od siparity between a manual and an automatic car making the same FWHP.

Secondly dyno ratings aren't BS. some folks just don't want to admit that they don't have prostock engines under their hoods.Final Power to the tire is Final power to the Tire PERIOD !If you have an automatic generally you are going to out 60ft out shift and stay on the power longer by using the TQ multiplication and slip built into the automatic power sucker Tq converter. Slip is slip and loss is loss if you really feel that you have a 725hp sbc gen3 engine prove me wrong and step up to plate and stick the damn thing on an engine dyno. I would call Bs becuase the stock intake runs out of air at about 560hp on 383 stroker and 540fwhp on a 347 a Fast intake isn't much better if at all and the ls2 while an improvement over the Fast and the ls6 isn't going to get you another almost 200hp.I work on alot of nice ls1's some running mid 9's and to be honest on the engine dyno and on the chassis dyno ( mustang) neither one makes anywhere near your assumptions or assertions. The car running mid 9's make 565 to the tire with a 250 shot and the motor alone runs low 11's with a 350whp pull. your not going to get a slew rate of loss increasing with power. that would the problem with your formulas. Drivetrian slip and loss is fairly fixed and is a drecreasing percentage with power gain at the flywheel.

To sum up what i am saying is put a TQ converter in a stock car loose 40hp. that 40hp loss will be extremly constant no matter how much power you make at the flywheel. the percentage will go from say a 20% drive line loss at 345fwhp to down to 10% at 560fwhp.

the formulas are wrong and inverted.they are not accurate. I have a guy running low 8's with 750whp and the engine dyno siad it was making right around 900 but that was with a neil chance converter and a glide. with accesories etc that loss is fiarly large but its also got a 5500stall converter. Your going to have increasing loss with higher stall converters.The idea of the converter is to get and keep the engine in its power band. I have seen many cars go up in stall loose mph and pick up ET.

To sum it up heres the breakdown.

dyno's ( mustangs at least) are accurate.You most likely don't need more power just more chassis and gearing and shifting to go faster. With 500whp with the converter unlocked you can easily run high 9's.

hell heres 505 SAE certified HP going 10.85 in the quarter enjoy the video.

http://www.youtube.com/watch?v=469NvIOiz7U

 

Pretty big spread on the ET predictions and HP estimates, Hales seems to be the best fit for my car, if my motor is making 650 at the crank. ET and MPH are within .1 s and 1mph of what the car runs.

Looking at the air consumption table for a 370 cu in ls1 making peak power at 5500 rpm and 15psi of boost it shows a air consumption of 66 lbs/min.
Here is the chart from jose's site.
http://www.forcedinductions.com/consumption370.htm

That should mean that my motor makes roughly 330 hp at the crank n/a which seems reasonable to me, 6.0 liter, 8.7:1, z06 cam, 317 heads.

Mike isn't it odd that we both appear to be off by about 200hp from the crank hp estimate based off the calculators? Didn't the guy on turbo mustangs who did the th400 swap lose about around 200 hp compared to his t56?

 

Was just thinking about what Collins said about stick cars and shifting, launch, etc. The average HP would be a lot lower on those cars when you take into account their power curves vs an automatic which usually gives a pretty flat line HP wise. I'm not sure about 200 HP less average HP but maybe it could be that high, time between shifts, poor launch all equal a lot less average HP. I'd like to rig up an accellerometer to my car and to a stick car that traps about the same and then average the HP over time and see what happens.

Another thing I was thinking about is the converter slip. I'm not sure what my converter slip percentage is but if it's around 18% at 6000 rpms, couldn't I gain some MPH by shifting around 6500 where the converter slip should be less due to better coupling (assuming I still make power at that rpm).

 

In theory you would be better shifting sooner as it forces the converter into a high slip situation where the disparity in input and output RPM force the turbine to basically lock up with fluid.it also depends on the converter. Typical converter slip goes up with stall. SO the higher the stall the less efficient it will be period no dicussion on this point its basic physics.

I have a feeling your research will pan out out on the stick vs auto.

 

here is my dyno numbers

i know two guys locally with similar mods, ones a stock stall, the other an m6 both dynoed around 335 on thew same dyno, different days...no locked numbers, didnt want to risk screwing **** up just for braggin rights...

one thing to note is how much gain in avg HP and TQ the tune gave me...and run 1 is the last run, run 2 came first...

 

Not all converter slip is inefficient. Some goes to fluidic
torque multiplication.



In Yank's chart you can see the converters still have some
residual torque multiplication after reaching near-peak
efficiency. So obviously there must be RPM slip if TQ is
being multiplied. But the observed slip is not all "lost";
some of it translates to a higher effective gear ratio instead.

The thing that would be most interesting, would be to see
locked and unlocked dyno curves but on a wheel MPH rather
than engine RPM basis. Focusing on RPM doesn't make so
much sense when the converter unlocked is smearing it.
But straight up, MPH for MPH, how much acceleration
producing torque comes out the back, that's a worthwhile
comparison. Too bad nobody prints dyno sheets that way.

 

I'll be right back with those hang tight. Checked the dynologs didn;t see any MPH runs saved that showed any variance with the MPH. I will have to go through it for a while.

 

whats wrong with your car ??? that thing has about the narrowest functional powerband i have ever seen out of an LS1. Oh wait i saw a fuddle in your signature and it look like your converter is not delivering enough of the engine power to the rear tire.

 

Mine is narrower. It makes power from 5400 - 5900 rpm, but runs just fine thank you.

 

wow that is really narrow. you must have a huge stall to make the numbers your posting up.

 

When I dyno'd, I had a Vigilante 9.5" 0 pump, which is normally rated at about 2800 rpm, but mine flashed to 5400 with the turbo 383. Peak hp was at 5700. Slip at the end of the quarter was around 20%. I've since replaced it with a 10.5" that's tighter and a 3.00 gear and now it only slips about 9% at the end of the track.

Mike

 

How was the MPH improvement ?

 

your guess is as good as mine, in hindsight, i should have done a baseline run before the stall, but i do know the car is running 8.1 in the 1/8th as opposed to 8.8 with the only change being the stall...

 

I would hope the converter pans out when you start making more power with heads/cam and some other work. But looking at the amount of slip in the graph I'd say that you will most likely need a more efficient converter to get the thing to hustle.

 

I don't see how you can determine the converter's
efficiency without either a locked baseline pull, or
at least logs of slip RPM and engine RPM (but slip
only tells the minimum and not the actual efficiency
in the midband).

I have a Fuddle that demonstrates 96% (by slip)
at 6000RPM and is still climbing but I shift there.
True, I tasked them specifically for this, and the
big clutch, etc. How spy's piece compares, can't
say. But we are not that far apart on the stall/STR
specs (3400/2.1 vs my 3500/2.0).

 

Hard to tell. . . I tightened up the converter, stroked the engine from 363 to 388, advanced the cam 4 deg, lowered the boost from 22 to 18, changed from 2.73 to 3.00 gears, installed skinnies up front, and ran it in cool weather. The change from from 143 mph to 146 mph.

Mike