Re: timing effects on hp
[Re: strokin73cuda]
#812876
09/23/10 08:30 PM
09/23/10 08:30 PM
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Joined: Jul 2010
Posts: 3,502 SOUTH JERSEY
HEMIFRED
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master
Joined: Jul 2010
Posts: 3,502
SOUTH JERSEY
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wow 44 views and not a peep from anyone and it's due to the wording of yopur question Quote:
What kind of general hp loss would you expect for every degree of timing thats to fast in a big block with 600ish horsepower
I 'll guess "too fast" is "too much" and make a statement that there is no specific answer. Any loss will vary according to the combo . I am sure a small chamered and large chameber differ by vast amounts. Can timing,compression fuel all contrbute in some way
home of the Sox and Martin Hemi Duster
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Re: timing effects on hp
[Re: 1badx]
#812884
09/24/10 02:14 PM
09/24/10 02:14 PM
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Joined: Nov 2004
Posts: 6,890 North Alabama
Monte_Smith
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Posts: 6,890
North Alabama
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In my opinion, timing is something that is very misunderstood, by most people. Many want to run as much as they can, because they think is makes power and that is not the case. The timing number, is simply when you light the cylinder and start the burn, nothing else. The more timing you need to run, to have enough time, to get a complete burn, really has the motor working against itself. The more before TDC you light the charge, the more that pressure is fighting the piston approaching TDC. In a perfect world, you would want a super efficient motor, that you could light off at TDC and have a complet burn, before the supposed ideal of 15* ATDC. Of course that can't happen, our engines are not that efficient yet, so we must start the burn earlier. But everyone should be concentrating on how to make their engines MORE efficient, so they need LESS timing, than trying to stuff all the timing they can in there. Even if you have an old school head design, with a not completely efficient chamber, you can still make that engine more efficient, with a modern intake, better valve job, modern cam profiles, properly tuned carbs and many other things, in the quest for maximum efficiency. These days, if your motor needs 38-40 degrees to make power, you have some really old school parts and are not even trying.
Monte
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Re: timing effects on hp
[Re: strokin73cuda]
#812886
09/24/10 05:18 PM
09/24/10 05:18 PM
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Joined: Jul 2006
Posts: 4,319 Puyallup, WA
StealthWedge67
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Puyallup, WA
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There's just no way to quantify this. The only way you'll know is to go out again, and run #'s off of you're trap MPH. In the long run, you'll know more after this issue, so its a good thing.
Last edited by GEnsrud; 09/24/10 06:59 PM.
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: timing effects on hp
[Re: strokin73cuda]
#812890
09/25/10 11:56 AM
09/25/10 11:56 AM
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Joined: May 2008
Posts: 5,399 Aurora, Colorado
451Mopar
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Joined: May 2008
Posts: 5,399
Aurora, Colorado
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As mentioned, it depends on the combination. When I first start tuning a new engine at the track, I use high octane fuel and slowly increase the total timing till the performance levels off, then usually go back to the previous setting. If it is a pump gas engine, after setting the timing as above, I will slowly reducing the octane rating, usually by mixing pump and race gas in various ratios while putting miles on the engine. Normally a performance timing curve works fine, but sometimes, with a truck or car with low stall (operates alot below 3,000 RPM), I will have to slow down the advance curve so total timing comes all in at a higher RPM.
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