Hey guyz, I took the Z to a dyno jet to see how it would run. My car puts down 470.9 on forged performances dd and it made 513 on this particular Dyno Jet, My concern is my MPH. They were making pulls in 4th gear and my top speed for the runs at the end of 4th was between 114 and 117. This Seems Very Low. Im running a VLSD from an Automatic 350z. Mine is manual but i did a pumpkin swap for a little bit more traction

 

This is not a dyno comparison but at 460whp on my 5AT, my mph in the 1/4 mile at the top of 4th @7k rpm was 125. It was as close to a perfect run as possible so the mph was pretty dead on. I backed it up on the next run with the same mph.

 

Interesting, I believe i might have gotten screwed with the VLSD i baught, Not sure though Possible another Issue> Any more advice would be great. Any way to tell what Gears i have in the rear end without opening the pumpkin

 

what speeds do you see in each gear? 35 in first? 60 in 2nd? 85 in 3rd?

 

Didnt max out each gear. when i get in the car tomorrow i can get you the info though. Just didnt have it from the dyno. It does seem that when im on the highway at 80MPH im at 3100 RPM in 6th. Which seems like shorter gears than my old Gear ratio

 

watch Alberto's vid and pause it at a specific rpm to get the mph and then see if your 3.3 is the same

 

Wow, Hell of an idea. lol just checked his vid and hes at 115 @6900 or so RPM so it seems mine is fine. Lol thanks man


PROBLEM SOLVED

 

4th gear in a 5AT is 1:1. In a 6MT, the ratio is 1.27. The final drive in the 5AT should be 3.357. For the 6MT is should be 3.538.

Coachk, I have a 3.538 ring gear, and I hit 140 mph around 7000+ rpms in 4th gear (26.1" diameter rear wheel/tire combo). Unless you have really small tires, you should hit it later, not earlier, with a stock 5AT rear final drive. Can you recall your rear wheel/tire size for that run?

 

What vid did you watch? I recall 7000rpm's in 4th on a 3.5 FD trapping 114-116mph at the track

I thought 7Krpm on the 3.3 was closer to 120mph, oh well Im sure your car is fine!

When I wind out 4th (not max though) I generally go to 130mph, but thats only when racing.

edit-watch this vid http://www.youtube.com/watch?v=0dYIoD6vxXE

pause at 1:04

at approx 7000rpm's in 4th Im at approx 123mph-BUT thats with a 27.2" street tire + 3.3 FD

60mph cruising in 6th is 2050rpm

 

I was on 26" D/R's....I'll be racing on June 13th so I'll look at the rpm as I go thru the trap and see where I'm at.

I'm not sure what you mean by this..(bold)

 

I was running 19x10.5 295/30/19 R888. And i was watching the 170+ mph Video you have in your Sig

 

295/30 = 26.0"

My stock track rears were 26.7" tall, I run 27.1" tall now

Im not a fan of shorter tires, such as the 295/30, visually I dont like them and for gearing and high HP they are blah

btw how did you get 115mph at 6900rpm's? It was easily 5mph higher than that...

 

He didnt print off a MPH Sheet for me so i honestly dont exactly recall. I just rember him commenting that it seems kinda slow for top of 4th. It was between 110-120 when he let off around 6800 rpm

 

you get dyno'd at phantasm?
they'd only run me up to 4th gear there.
4 gear pulls FTL

 

My car was similar.

With 3.5FD, 26.5in tire, going through the traps on the stock rev limiter in 4th (6500-6800rpm somewhere in there), 118mph.

now with the 3.3FD and bumped rev limiter I can get to 130 in 4th

tom