Subject	I have gotten better numbers in 4th than 3rd on the
Posted by	AzHeat on August 10, 2004 at 12:17 PM
	This message has been viewed 52 times.
In Reply To	dyno pull-3rd or 4th gear posted by eriksu9 on August 10, 2004 at 10:35 AM
Message	tt that is. 4th gear puts the engine under greater load than 3rd gear. The greater the load, the faster the turbos spool up and the sooner you get torque from boost. That is why you don't dyno in 1st or 2nd gear because the engine will out run the turbo before they had a chance to spool up. You will already hit your rev limit and the turbos barely got a chance to boost. Aside from frictional losses of 3rd gear vs 4th. In an NA car, the difference is minimal. Remember, the dyno jet is measuring the amount of work performed on the rollers. It doesn't care what gear ratio is being used to calculate HP. It still knows how fast the drums were spun and how many revolutions were spun and the amount of time it took. Power = work/time ; work = force x distance ; force = mass x acceleration. HP = rpm x torque /5250 . Gear ratio is not part of the equation for HP. It can figure out the (final) gear ratio by drum speed and the engine rpm.
Follow Ups	dyno pull-3rd or 4th gear - eriksu9 10:35:38 08/10/04 Proper gear is 4th - ImTheDevil 10:37:43 08/10/04 What are you asking? - Technomancer 10:43:43 08/10/04 4th gear is 1:1 - eroc77 10:49:16 08/10/04 I don't see why - Technomancer 10:55:08 08/10/04 It's not that 4th is more efficient - Rob'Z 11:07:32 08/10/04 Im claiming that it will give the most accurate.... - eroc77 11:11:06 08/10/04 1:1 has the least amt of friction being transferred through - Chris(NJ) 11:11:45 08/10/04 Sorry, I'm not trying to be dense here but I still don't see - Technomancer 11:28:29 08/10/04 Relax and stop overthinking it. - SeedyROM 12:57:17 08/10/04 This is the theory - Chip(GMS Racing) 13:07:15 08/10/04 "directly connected" just isn't true - Technomancer 13:19:10 08/10/04 I was regurgitating what I read somewhere - Chip(GMS Racing) 13:23:24 08/10/04 I don't think the dyno needs to know the gearing info. - Marshall 13:22:31 08/10/04 yes, I'm claiming that the number is needed as an input to t - Technomancer 13:30:53 08/10/04 4th gear is 1:1 so it will give "correct" numbers - Rob'Z 10:48:45 08/10/04 Did you forget the existence of the rear differential? - Technomancer 10:54:24 08/10/04 ? (n/m) - Chris(NJ) 11:04:44 08/10/04 Huh? So you're saying I should divide the RWHP numbers - Rob'Z 11:11:22 08/10/04 Yes, I'm saying that is what the dyno does - Technomancer 11:25:40 08/10/04 i believe 5th is only closer in a 6spd. (n/m) - Chris(NJ) 11:32:07 08/10/04 correct-5th is usually 1:1 in a 6sd - Rob'Z 11:44:33 08/10/04 Ugh you guys! Multiply by the rear diff - Technomancer 11:51:27 08/10/04 Free your mind - Rob'Z 16:10:40 08/10/04 You get no torque multiplication from the tire. (n/m) - Technomancer 16:30:44 08/10/04 Yeah I was being a little sarcastic there - Rob'Z 11:41:21 08/10/04 a lot of shops do not know how to dyno autos. kinda sad - Chris(NJ) 11:04:08 08/10/04 didn't the dyno shop you took us to ask us if our cars - ZEngineer (TT) 13:02:02 08/10/04 Use the dyno as a tuning tool, not a contest - vorpalZ 12:07:14 08/10/04 I have gotten better numbers in 4th than 3rd on the - AzHeat 12:17:37 08/10/04 Oh geez you are so wrong! - Technomancer 12:26:17 08/10/04 He is correct about turbos spooling quicker in higher gears - Chip(GMS Racing) 12:32:25 08/10/04 Yes I have nothing to say about the spooling - Technomancer 12:51:54 08/10/04 A real world example - Chip(GMS Racing) 13:21:02 08/10/04 An interesting tidbit: - Marshall 13:31:56 08/10/04 I agree, I FIRMLY believe that my car would have been faster - Chip(GMS Racing) 13:55:02 08/10/04 That's where torque mulitplications comes in a - AzHeat 12:35:30 08/10/04 you are confusing engine RPM and drum RPM - Technomancer 12:47:25 08/10/04 Show me where in the HP equations and the - AzHeat 13:18:04 08/10/04 OK, let me soften my stance: - Technomancer 14:02:03 08/10/04 Please give the mathematics equation for this - AzHeat 14:33:21 08/10/04 for what part? (n/m) - Technomancer 14:41:52 08/10/04 The gear ratio is already accounted for in the - AzHeat 15:25:42 08/10/04 yep - Technomancer 16:24:14 08/10/04 Re: dyno pull-3rd or 4th gear - eriksu9 13:42:12 08/10/04 good luck. This has been very interesting! (n/m) - Technomancer 14:03:02 08/10/04 Dyno at 1:1(or gearing closest to 1:1) to compare >> - I am Z-ing Double 15:23:59 08/10/04 I'm surprised you tech-heads haven't mentioned dyno - vorpalZ 15:59:47 08/10/04
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