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Where is my HP going after 60' and why?
https://slantsix.org/forum/viewtopic.php?t=40948		 Page 2 of 3
Author:  Mister Twister [ Fri Jul 09, 2010 5:03 am ]
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Oh yes wind drag, track surface/uneven, temperature/Humidity. Thanks for that hit in the head. Doe :shock:

95 HP difference wow. Now 30 HP loss on my run, don't seem to bad. I would still like to get some of it back!! :?

SV162 Thanks that was easy and did it in the in the A/C. Might find another calc and get some more back. :D

Let's see. If you all were to do the same thing with calc that I did with your time slip, would it read in the same manor? :arrow:
Author:  Charrlie_S [ Fri Jul 09, 2010 5:20 am ]
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As previously stated, MPH is better for figuring HP. Remember max HP and max torque are at only one RPM, and they are at Different RPM's. 60 foot times are a better indication of the torque the engine is makeing. My 170 engine is making 328 ft/llbs torque at 2900 rpm, and will do 1.79 60 foot time with a 3200 lb car. The rear wheel HP is 204 at about 5500 rpm, and runs 98 mph in the quarter.

One other thing about online, or even calculator programs you can purchase, the "absolute" number is not necessarily acurate (as you have seen, they vary by which calc you use), but the increase/decrease in the numbers on the same calc, after changes to the engine/car, are valid.
Author:  Dart270 [ Fri Jul 09, 2010 6:07 am ]
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I bet they didn't degree the cam and it is way far advanced, and your ign timing should be checked too.

Lou
Author:  Mister Twister [ Fri Jul 09, 2010 8:20 am ]
Post subject: 
Quote:
As previously stated, MPH is better for figuring HP. Remember max HP and max torque are at only one RPM, and they are at Different RPM's. 60 foot times are a better indication of the torque the engine is makeing. My 170 engine is making 328 ft/llbs torque at 2900 rpm, and will do 1.79 60 foot time with a 3200 lb car. The rear wheel HP is 204 at about 5500 rpm, and runs 98 mph in the quarter.

One other thing about online, or even calculator programs you can purchase, the "absolute" number is not necessarily acurate (as you have seen, they vary by which calc you use), but the increase/decrease in the numbers on the same calc, after changes to the engine/car, are valid.
If you all were to do the same thing with calc that I did with your time slip, would it read in the same manor? Thanks for joining in on this Charlie.
Author:  Mister Twister [ Fri Jul 09, 2010 9:05 am ]
Post subject: 
Quote:
I bet they didn't degree the cam and it is way far advanced, and your ign timing should be checked too.

Lou
This sounds like a good place to start getting my Hp back on the track. :)
!Image
I have a few of these I am finishing, this will give me a reason to install one. 8)
Any recemendations on where to set it? Its a small CompCams 260/440.
Author:  slantzilla [ Fri Jul 09, 2010 2:24 pm ]
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As well as the car is 60'ing I find it hard to believe the cam is retarded. 2.0 is a damn good 60' for a car that slow.

One other thing you have to remember, a little cubic inch motor will not run as hard downtrack as a bigger motor.

Mine on the hose would run dead even with my buddy's 440 Challenger to half track. From half track on he would put 3 tenths and 7 MPH on me. :cry:
Author:  Rick Covalt [ Fri Jul 09, 2010 3:03 pm ]
Post subject:  Reference
Just as a reference, Ryan's Dart at 3170#(No Driver) went 2.04 60ft time and ran 14.8 in the quarter. You definitely have a good launch but are loosing something on the top end.

Rick
Author:  ryandcovalt [ Fri Jul 09, 2010 5:16 pm ]
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The last test and tune I was at my car ran 16.1 the first time out (usually runs 14.8-15.1). The problems was a clearance issue with my air filter setup (long story) but it was basically choking the engine out. It seemed to run perfect at normal rpm's, even 60ft times were normal, but lost mph/et on the top end. As soon as I changed the filter setup the very next pass was back to normal low 15's. Could there be some type of restriction with your engine? Filter clearance issue, Carb or choke issue? Hopefully there is something simple that will give you that top end power, cause your 6oft times are good.
Author:  Mister Twister [ Sun Jul 11, 2010 1:31 pm ]
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Quote:
From what I'm reading, you have a mechanical advance with very light springs that come all in at idle?

CJ
Is that a bad thing :?: Set it and for get it :!: Sounds like a commercial, no i'm not trying to sell you the idea of fixed. :lol: What change would do :idea: welcome.
Author:  slantzilla [ Sun Jul 11, 2010 4:20 pm ]
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Just as a reference, my GTO went a 2.04 60' on a 13:89 pass.

Last night in the crap air down at 41 it was going 2.10 and 14:50. :shock:
Author:  Mister Twister [ Mon Jul 19, 2010 3:44 pm ]
Post subject: 
I will make one more night of testing then some kind of change. Any other ideas :?: Now it has a loss of 30HP from the 60' to 1/4 mile. I really don't want to see any loss!!! Is that passable?
Author:  Charrlie_S [ Mon Jul 19, 2010 5:26 pm ]
Post subject: 
Quote:
I will make one more night of testing then some kind of change. Any other ideas :?: Now it has a loss of 30HP from the 60' to 1/4 mile. I really don't want to see any loss!!! Is that passable?
Not possible. You are measuring two different things at two different rpm. Look at a dyno chart, and compare it to the RPM at the points you are measuring. Also, at one point you are measuring ET (60 ft). and the other point you are measuring MPH (1/4 mile).
Author:  ryandcovalt [ Mon Jul 19, 2010 6:04 pm ]
Post subject: 
I don't have any great suggestions, but for a reference here is my time slip broken down by a hp calculator (3330lbs):

60ft time: 2.039 171.97 whp
1/8 mile: 9.437 180.48 whp
1/8 mile: 72.48mph 186.20 whp
1/4 mile: 14.83 179.90 whp
1/4 mile: 91.22mph 180.54 whp

I ran your time slip on the same calculators as a comparison. (3400lbs)
60ft time: 2.0 187.05 whp
1/8 mile: 10.0 154.87 whp
1/4 mile: 16.27 140.43 whp
Looks like this calculator shows an even bigger difference! It would be interesting to see what it says with your mph numbers.

One thing with a 60ft calculator is the slightest et difference greatly affects the hp numbers. Did you run an exact 2.0 60ft? I ran your numbers with a 60 ft of 2.05, and hp drops to 172.5hp. The 60ft calculator is extremely sensitive. You may have known that already, but I didn't realize how big of a difference a few hundredths makes on the 60ft calculator. Hope this at least gives you a reference.
Author:  sergio G [ Tue Jul 20, 2010 9:07 pm ]
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You are not losing any hp,your trap speed /weight formula will give you the hp for that particular run. You cannot use 60 ft to compute hp. as an example the Dart i ran last year did 1.90 sixty s.At the last Redding race last year had six straight 1.90 and a1.89. Why? the car weight 2450 with driver, 4,30 rear gear with spool ,a sticky tire and a 3600 stall converter.Best et 14.99,engine is 100% internally stock,has a hedder and a holley500 2 barrel. Fastest speed with this combo only 85mph,so i have at best 150hp but the car would outrun a lot of 13 second cars to the 330 mark then the accelaration went away. Use your trap speed to compute hp ,then tune for speed and then you can calculate what your best potential e.t would /should be.
Author:  sergio G [ Thu Jul 22, 2010 9:06 am ]
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I had another theory ,not sure what rear end gears you have. On my dart the 1/4 milr rpms were 5100 with 3.91 gears and 5000 with 4.30 gears, makes no sense. Howeve rhe converter is too loose for this combo so when i go into high gear the converter is not fully locked up causing slippage and loss of et. My converter will only go 2800 max, you say yours goes to 3000. That may explain the loss of et the last eight . I do agree you should be running quicker from the 1/8 to the 1/4
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