What gear do they run Dyno's in?

Mitco39 · 12-06-2012, 10:04 AM

Hi Guys,

I spent a couple hours putting together an acceleration spreadsheet for our cars. So far my acceleration times are off when compared to stock specs. My input data was a run with a max hp of 280 and a max tq of 225. What gear would this have been in on a automatic on the dyno? Gear 7? or do they have a way to lockout gears when on the dyno.

I know generally you want to use a 1:1. Also if a gear other than 5th was used do they scale the graph accordingly?

The reason I ask is with the data I currently have and my calculations it is taking way to long to wined out 1st gear (5.47 seconds) and I am just trying to figure out where I went wrong.

Thanks

Mitch

nmjaxx9 · 12-06-2012, 10:51 AM

if its an 7AT it would be in 6th.

SouthArk370Z · 12-06-2012, 10:57 AM

Quote:

Originally Posted by nmjaxx9

if its an 7AT it would be in 6th.

Excuse my ignorance, but why 6th? Wouldn't 5th (1:1) be better? If 6th is better than 5th, why not 7th?
[assumes lotus position and awaits enlightenment]

Mitco39 · 12-06-2012, 11:00 AM

I think it would depend on the dyno, as long as you take into account torque advantages (or disadvantages) you would get the same numbers.

Which is why I am wondering if they do scale it to a 1:1.

FPenvy · 12-06-2012, 11:04 AM

Quote:

Originally Posted by nmjaxx9

if its an 7AT it would be in 6th.

it's 5th.

nmjaxx9 · 12-06-2012, 11:09 AM

Quote:

Originally Posted by SouthArk370Z

Excuse my ignorance, but why 6th? Wouldn't 5th (1:1) be better? If 6th is better than 5th, why not 7th?
[assumes lotus position and awaits enlightenment]

7th is considered an overdrive, at 0.77 something from my knowledge, 6th would be closer to 1:1 (around0.8) 5th might be a straight 1.00 either 5th or 6th would be an ideal gear. But I think 5th is the right one not 6th

NickTurnon · 12-06-2012, 11:32 AM

5th Gear 1:1

FPenvy · 12-06-2012, 11:34 AM

7AT gear ratios:

1 - 4.924
2 - 3.194
3 - 2.043
4 - 1.412
5 - 1.000
6 - .862
7 - .771

Mitco39 · 12-06-2012, 11:42 AM

I got it figured out. I mathematically calculated the acceleration for every gear with a 3.357 FD in a AT. On paper I have a 0-60 time of 4.1s not including shift time (so right around what you would expect). I also have a top speed of right around 162 mph which where the wind resistance overcomes the power.

This was all done with a 280 hp rear wheel dyno chart, so your typical stock car. I started making it yesterday to show the differences a change in the final drive will cause you both in acceleration and top speeds. I am going to tidy it up and then post it up.

Mitco39 · 12-06-2012, 11:43 AM

I also charted out all the FD's with respect to gearing.

FPenvy · 12-06-2012, 11:44 AM

Quote:

Originally Posted by Mitco39

I got it figured out. I mathematically calculated the acceleration for every gear with a 3.357 FD in a AT. On paper I have a 0-60 time of 4.1s not including shift time (so right around what you would expect). I also have a top speed of right around 162 mph which where the wind resistance overcomes the power.

This was all done with a 280 hp rear wheel dyno chart, so your typical stock car. I started making it yesterday to show the differences a change in the final drive will cause you both in acceleration and top speeds. I am going to tidy it up and then post it up.

sounds like too much math. just get in it drop the hammer and see what happens.

XwChriswX · 12-06-2012, 04:06 PM

I've had 1 dyno in 3rd gear, 2 dynos in 4th gear, and 1 attempted dyno in 5th gear. So my baseline/modded numbers don't match up at all.

That's why I wanna get a tune so they can take off the 155mph limit and I can actually do a full 5th gear run for accurate numbers.

Also, don't they when they tune do the pulls in 4th gear?

FPenvy · 12-06-2012, 04:08 PM

Quote:

Originally Posted by XwChriswX

I've had 1 dyno in 3rd gear, 2 dynos in 4th gear, and 1 attempted dyno in 5th gear. So my baseline/modded numbers don't match up at all.

That's why I wanna get a tune so they can take off the 155mph limit and I can actually do a full 5th gear run for accurate numbers.

Also, don't they when they tune do the pulls in 4th gear?

typically the 6MT is 4th and 7AT is 5th due to gearing. 5th in the 7AT is exactly 1.00

XwChriswX · 12-06-2012, 04:56 PM

Quote:

Originally Posted by FPenvy

typically the 6MT is 4th and 7AT is 5th due to gearing. 5th in the 7AT is exactly 1.00

Of course, but once you're pretty well modded, you'll top out at 155 before you top out at 7500 rpms. Thats why they had to do mine in 4th.

FPenvy · 12-06-2012, 04:58 PM

Quote:

Originally Posted by XwChriswX

Of course, but once you're pretty well modded, you'll top out at 155 before you top out at 7500 rpms. Thats why they had to do mine in 4th.

well arent you special

12-06-2012, 10:04 AM	#1 (permalink)
Mitco39 A True Z Fanatic Join Date: Aug 2012 Location: Edmonton Alberta Canada Posts: 2,089 Drives: 40th 370z Rep Power: 132	What gear do they run Dyno's in? Hi Guys, I spent a couple hours putting together an acceleration spreadsheet for our cars. So far my acceleration times are off when compared to stock specs. My input data was a run with a max hp of 280 and a max tq of 225. What gear would this have been in on a automatic on the dyno? Gear 7? or do they have a way to lockout gears when on the dyno. I know generally you want to use a 1:1. Also if a gear other than 5th was used do they scale the graph accordingly? The reason I ask is with the data I currently have and my calculations it is taking way to long to wined out 1st gear (5.47 seconds) and I am just trying to figure out where I went wrong. Thanks Mitch __________________ 2007 Chevy Duramax - EFILive Tuned By Me 2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her My Build --> http://www.the370z.com/members-370z-...39s-build.html

12-06-2012, 11:00 AM	#4 (permalink)
Mitco39 A True Z Fanatic Join Date: Aug 2012 Location: Edmonton Alberta Canada Posts: 2,089 Drives: 40th 370z Rep Power: 132	I think it would depend on the dyno, as long as you take into account torque advantages (or disadvantages) you would get the same numbers. Which is why I am wondering if they do scale it to a 1:1. __________________ 2007 Chevy Duramax - EFILive Tuned By Me 2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her My Build --> http://www.the370z.com/members-370z-...39s-build.html

12-06-2012, 11:32 AM	#7 (permalink)
NickTurnon A True Z Fanatic Join Date: Jul 2011 Location: Scottsdale Age: 33 Posts: 1,636 Drives: 09 BS 7AT 370z Rep Power: 18	5th Gear 1:1 __________________ 2009 Brilliant Silver BASE 7AT \| TEIN S-Tech Springs \| K&N Drop Ins & z1 Maf Tubes \| AAM S-Line Short Tails \| 5% Tint \| 20MM Spacers \| Sport Spoiler NickTurnon's 370z Build

12-06-2012, 11:42 AM	#9 (permalink)
Mitco39 A True Z Fanatic Join Date: Aug 2012 Location: Edmonton Alberta Canada Posts: 2,089 Drives: 40th 370z Rep Power: 132	I got it figured out. I mathematically calculated the acceleration for every gear with a 3.357 FD in a AT. On paper I have a 0-60 time of 4.1s not including shift time (so right around what you would expect). I also have a top speed of right around 162 mph which where the wind resistance overcomes the power. This was all done with a 280 hp rear wheel dyno chart, so your typical stock car. I started making it yesterday to show the differences a change in the final drive will cause you both in acceleration and top speeds. I am going to tidy it up and then post it up. __________________ 2007 Chevy Duramax - EFILive Tuned By Me 2010 40th W/ Nav - Boosted Performance - UpRev Tuned By Me The Mrs. Ride -2012 335XI N55 BMW - Cobb Tuned By Me, Built by her My Build --> http://www.the370z.com/members-370z-...39s-build.html

12-06-2012, 04:06 PM	#12 (permalink)
XwChriswX WFLYIDNNE Join Date: Jul 2009 Location: In The Fastlane Posts: 50,648 Drives: 02 GDB WRX Rep Power: 452	I've had 1 dyno in 3rd gear, 2 dynos in 4th gear, and 1 attempted dyno in 5th gear. So my baseline/modded numbers don't match up at all. That's why I wanna get a tune so they can take off the 155mph limit and I can actually do a full 5th gear run for accurate numbers. Also, don't they when they tune do the pulls in 4th gear? __________________ Bonnie - Stage 2, Audio build coming this fall! R.I.P. Abby 3/29/10 - 3/30/14

12-06-2012, 10:51 AM	#2 (permalink)
nmjaxx9 A True Z Fanatic Join Date: Jul 2011 Location: Middletown, Ct Posts: 5,853 Drives: 2011 Nissan 370z Rep Power: 26	if its an 7AT it would be in 6th.

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