Optimum shift RPM - HR
#1
Registered User
Thread Starter
iTrader: (1)
Join Date: Sep 2008
Location: Ajax, On
Posts: 666
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
So I got my dyno done and much to my surprise I was shifting just before redline which does not seem to be the best spot.
![Name: pg0001_lg.jpg
Views: 908
Size: 73.4 KB](https://my350z.com/forum/attachments/vq35hr/445533d1502131791-optimum-shift-rpm-hr-pg0001_lg.jpg)
Looks like I need to be shifting at 7,100 RPM, not 7,400!!
![Name: pg0001_lg.jpg
Views: 908
Size: 73.4 KB](https://my350z.com/forum/attachments/vq35hr/445533d1502131791-optimum-shift-rpm-hr-pg0001_lg.jpg)
Looks like I need to be shifting at 7,100 RPM, not 7,400!!
#5
Registered User
iTrader: (35)
Join Date: Nov 2007
Location: louisvile KY
Posts: 852
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
By looking at your graph I would be shifting at 6900 rpms. That's when your power starts to drop. You need to stay in the power range so she charges into the next gear so power is still going up. If you shift at redline you will get poor results. In my Z I shift at 6500 rpms my red line is set at 7200rpms
#6
Registered User
iTrader: (5)
![Default](https://my350z.com/forum/images/icons/icon1.gif)
By looking at your graph I would be shifting at 6900 rpms. That's when your power starts to drop. You need to stay in the power range so she charges into the next gear so power is still going up. If you shift at redline you will get poor results. In my Z I shift at 6500 rpms my red line is set at 7200rpms
The image illustrates it best, the amount of work the engine is capable of from 4500-5000rpm is less than the amount from 7000-7500rpm. The overall total area under the curve from shifting 500rpm sooner in our hypothetical scenario is less by short shifting.
TK
#7
Registered User
Thread Starter
iTrader: (1)
Join Date: Sep 2008
Location: Ajax, On
Posts: 666
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
Not stock.
T_K:
I greatly appreciate your time and input! Keeping it in the powerband is key to keeping it moving. I do both drag and road racing so knowing the cars strengths is key to my improvement. After a review of your post I see that probably 7,275 would most likely be the optimal point for the shift. The RPM's seem to drop by about 1,750 per gear at a constant velocity (100 KM/H).
Thanks for all your input.
T_K:
I greatly appreciate your time and input! Keeping it in the powerband is key to keeping it moving. I do both drag and road racing so knowing the cars strengths is key to my improvement. After a review of your post I see that probably 7,275 would most likely be the optimal point for the shift. The RPM's seem to drop by about 1,750 per gear at a constant velocity (100 KM/H).
Thanks for all your input.
Trending Topics
#8
Registered User
Join Date: Jul 2008
Location: Los Angeles, Ca
Posts: 658
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
Best shift point is at the peak of the HP. I did some racing tonight and found higher trap speeds shifting my auto. I did shift once manually via triptronic going into 3rd @ 6,900 rpm where my peak is and it gained 1mph on the 1/8 trap speed to what I normally get when the car shifts itself around later 7,400.
Best shift point at peak HP.
Best shift point at peak HP.
#9
Registered User
iTrader: (2)
Join Date: Jul 2007
Location: Rockville
Posts: 1,634
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
Best shift point is at the peak of the HP. I did some racing tonight and found higher trap speeds shifting my auto. I did shift once manually via triptronic going into 3rd @ 6,900 rpm where my peak is and it gained 1mph on the 1/8 trap speed to what I normally get when the car shifts itself around later 7,400.
Best shift point at peak HP.
Best shift point at peak HP.
I will tell you from experience however that shifting any higher than 7500 (if you have the reflash) will slow you down.
https://my350z.com/forum/drag/394262...s-tonight.html
#10
Registered User
Join Date: Jul 2008
Location: Los Angeles, Ca
Posts: 658
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
I'm just going by these.
stock 5A shifts
60' : 2.02
330:5.64
1/8:8.60
MPH:82.66
vs. 5A 1st-2nd + 2nd-3rd manual shift at the peak hp
60':2.19
330:5.86
1/8:8.80
MPH:83.49
if someone wants to analyze this.
stock 5A shifts
60' : 2.02
330:5.64
1/8:8.60
MPH:82.66
vs. 5A 1st-2nd + 2nd-3rd manual shift at the peak hp
60':2.19
330:5.86
1/8:8.80
MPH:83.49
if someone wants to analyze this.
Last edited by infinite; 11-01-2008 at 01:53 PM.
#14
Registered User
Join Date: Jul 2008
Location: Los Angeles, Ca
Posts: 658
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
you guys are right, it's just that the auto is different, since it drops at a set stall speed. I read that the optimum shift points vary for each gear. there's a a calculation for the ideal shift points, however if you're not doing the calculation, the redline is the closest to the ideal.
#16
Registered User
Join Date: Jul 2008
Location: Los Angeles, Ca
Posts: 658
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
it was, but the VQ37HR is what's hot now. The 370z is coming. it may have 7speed transmission. Same types of mods on that thing will probably be about 330whp, a good difference backed by light weight, an easy 12second car.
#17
Registered User
Join Date: Jul 2008
Location: Los Angeles, Ca
Posts: 658
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://my350z.com/forum/images/icons/icon1.gif)
it was, but the VQ37HR is what's hot now. The 370z is coming. it may have 7speed transmission. Same types of mods on that thing will probably gain about be about 330whp for the m/t, a good difference backed by light weight, an easy 12second car.
Thread
Thread Starter
Forum
Replies
Last Post
MAsSIVrOOM
Engine & Drivetrain
2
10-20-2023 10:50 AM
ars88
Zs & Gs For Sale
18
04-04-2016 07:52 AM
Justin100
Intake Exhaust
26
11-29-2015 03:58 PM