Maximum Acceleration: Z33 Trans or Z32 Trans Upgrade (Paging smart guys haha)

[CodyAce]

Long story short, I think we all realize S chassis transmissions suck. I'll be on my 3rd now in 6 years at my power level (400whp)

SO the thought of upgrading has came into play. Obviously the Z32 swap will not break, be plenty, and work...however is it ideal? With ratios close the S chassis boxes', I can assume how it will react.

Now enter the Z33 option. These can be found cheaper and cheaper, are same price as the Z32 setups, and honestly are appealing to me just on the fact of them being new.

Now comes into the ratio per speed question: What setup would really get me to my desired speed fastest!?!?! I understand that shorter gearing will get me to XXX mph, however I also understand it will limit distance traveled.

As it is, I have a 4.6 final drive in my car. It gets rid of that annoying 'low spot/high spot' debate in gears by keeping me in the next gear up.

So hear is my break down in total speed per gear. I also included total top speed per different ratio:

4.6, SR 8000 39 69 100 131 172
4.08, SR 8000 44 78 113 148 194
3.94, SR 8000 46 80 117 153 201
3.55 SR 8000 51 89 130 170 224

4.6 Z33 8000 35 56 81 116 131 165
4.08SR 8000 39 64 91 131 148 186
3.94 Z33 8000 40 66 94 136 153 193
3.55 Z33 8000 45 73 104 151 170 214


To me, Going to that 4.08 ratio will give me similar gearing with Z33 trans as I have now. However would going with that 3.9 setup be really ideal? Heck it seems like the 3.55 gear may even be BETTER in total than what I have now in terms of total speed per gear?

Cliffs: What would be the best setup in regard to acceleration. I have the 4.6 gear now, and love the 130 mph 4th gear limit, but would love to further optimize my setup.

[McCoy]

http://www.nissanroadracing.com/showthread.php?t=2566

[turtl631]

Great deal on that dogbox, but I don't think Cody wants to run that on his street car

[logr]

Total speed in gear will always go up with a higher rear ratio but it could also possibly drop you out of your power band between gears(bigger jump). Not sure what you do with the car but do you really want or need to go 214 mph? If not, you are not fully using the box.

Leaving the 4.6 in will still give you the 130 mph you like but with an extra gear in between to always keep you in the sweet spot in the speed bracket you use the most(guessing here). The question, in my mind, is do you need or want an extra gear to keep the engine in the power band? Means more shifting.

For autox, 70ish in 2nd is about right or going low enough to put you into 3rd more often works too. In which case the 4.6 works pretty well. I had pretty much this exact ratio and it worked great on track days because of the extra pull out of corners. It is a bit of extra shifting in autox and possibly traction limited.

Not sure if that helped but it might give you more to think about or a different perspective.
I try to stop thinking about these kind of problems when smoke comes out of my ears.
Why did you not include a 4.3?

[CodyAce]

Great deal on that dogbox, but I don't think Cody wants to run that on his street car

As much as I'd love something like that, I'll also be the first to admit that I'm not willing to devote that sort of committment to my car. I still do like the 'turn key, go get milk' aspect of it...as much as I pretend it's a track car, it's still a street car at the end of the day hehe.

Total speed in gear will always go up with a higher rear ratio but it could also possibly drop you out of your power band between gears(bigger jump). Not sure what you do with the car but do you really want or need to go 214 mph? If not, you are not fully using the box.

It's not so much oriented in top speed, but more in the 40-160 range, where I spend most of the day on track. As it stands, the 4.6 FD and SR box works pretty well, but I'm wondering if changing the current 2-4 run to the Z33 box would make it any quicker...

I mean as it stands, the car does everythign exceptionally well...IMO a car that drag races through all gears into the traps is almost geared perfectly well...which my car does...but if I could get another gear into the mix to further help push the car...would that help move the car...or would the shift slow me down?

The question, in my mind, is do you need or want an extra gear to keep the engine in the power band? Means more shifting.

And that's my other concern...to me, an extra shift would ultimatly make the car slower. However would the closer ratio of the Z33 setup enable it to move out faster? That's I guess my big delemna....as it stands I think the car is pretty good gear wise, but there are times where I wouldn't mind a little more 3rd gear umph...but I think I would actually loose some with the Z33 setup.

Not sure if that helped but it might give you more to think about or a different perspective.
I try to stop thinking about these kind of problems when smoke comes out of my ears.

That's my issue now LOL! I know I need a stronger transmission...I know my current setup runs damn well...but In this case if I'm going to drop the cash on a bulletproof transmission, I want the best possible setup hehe.

Why did you not include a 4.3?

I honestly forgot Added below:

4.6, SR 8000 39 69 100 131 172
4.3, SR 8000 42 74 107 140 185
4.08, SR 8000 44 78 113 148 194
3.94, SR 8000 46 80 117 153 201
3.55 SR 8000 51 89 130 170 224





4.6 Z33 8000 35 56 81 116 131 165
4.3 SR 8000 37 60 86 110 140 176
4.08Z33 8000 39 64 91 131 148 186
3.94 Z33 8000 40 66 94 136 153 193
3.55 Z33 8000 45 73 104 151 170 214

[CodyAce]

In the end, the car rolls 2nd to 4th gear, 40-130 without issue...that's a damn good 'sprint' persay....but would going to a Z33 box, where it's a 2.3 to a 1.6 to a 1.2 (4.08 final drive) ratio spread get me there faster than the current 1.9 1.3 1.0 (4.6 final drive)

I know it will hit the same maximum speed in 4th, but what would be ideal.

[KA240SX808]

Got a recent Dyno of the motor? Might be able to give you some figures to look at.

[logr]

Maybe it's just a fluke but I am doing a TT conversion on an NA 300ZX.
A local shop inherited it from another shop that had given up after installing the engine and the local shop called me.
They had used the NA tranny.
I changed the oil in the tranny today and chunks came out with it.
Not sure what an NA 300ZX has for power but considering the TT is 300, it must be considerably less and yet the tranny is toast.

Would have been nice if someone had checked it out before installing it in the car but then they omitted the lower injector Orings so I expect anything.
An engine hydro locks very quickly that way.

[Beejis60]

I think you're almost over-thinking it.

Why not go with a sequential shifter if you're worried about shifting speeds?

[CodyAce]

I think you're almost over-thinking it.

Why not go with a sequential shifter if you're worried about shifting speeds?

It's not so much shifting speeds, it's if a car will be 'quicker' 40-130 with Z32 or Z33 gearing.

[KA240SX808]

So you didn't post a Dyno like I asked but I got bored and set out to find your most recent one...

I used this one from the GT2871R thread off Zilvia:


Here's some basic info which you may already know, maybe not but here it goes.

Set-up 1:
*Numbers are assuming:
- S13 SR Trans (.759 5th)
- 265/35/18 (NT-05 Size you were looking @)
- 4.646 FD (Mentioned in here)
- Shifting done @ 7250 (Graph only shows up to ~7300rpm)

60mph = ~2800rpm

RPM Drops:
1st-2nd = 4152rpm
2nd-3rd = 4985rpm
3rd-4th = 5542rpm
4th-5th = 5502rpm

To my understanding Accel = Trq
Avg. Trq. when Accelerating from 40-130 = 163.97ft lbs @ the Wheels (Numbers look small because there figures from the wheel not trq. output from the Flywheel)
- RPM Range = 4750 in 2nd to 6000rpm in 5th


Set-up 2:
*Numbers are assuming:
- Z32 Trans
- 265/35/18 (NT-05 Size you were looking @)
- 4.646 FD (Mentioned in here)
- Shifting done @ 7250 (Graph only shows up to ~7300rpm)

60mph = ~2800rpm

1st-2nd = 4342rpm
2nd-3rd = 4903rpm
3rd-4th = 5568rpm
4th-5th = 5452rpm

Avg. Trq. when Accelerating from 40-130 = 164.60ft lbs @ the Wheels (Numbers look small because there figures from the wheel not trq. output from the Flywheel)
- RPM Range = 4750 in 2nd to 6000rpm in 5th


Set-up 3:
*Numbers are assuming:
- Z33 Trans
- 265/35/18 (NT-05 Size you were looking @)
- 4.646 FD (Mentioned in here)
- Shifting done @ 7250 (Graph only shows up to ~7300rpm)

60mph = ~2925rpm

1st-2nd = 4440rpm
2nd-3rd = 5066rpm
3rd-4th = 5674rpm
4th-5th = 5704rpm
5th-6th = 5756rpm

Avg. Trq. when Accelerating from 40-130 = 171.56ft lbs @ the Wheels (Numbers look small because there figures from the wheel not trq. output from the Flywheel)
- RPM Range = 5750 in 2nd to 6750 in 6th

If your wondering how I got those numbers what I did was take the Trq. output at the given RPM windows in each gear and divide them by how many RPM windows were added starting from the Closest RPM @ 40mph to the Closest RPM @ 130mph


Your trq. is pretty flat from 4250 all the way to 6750 so that's why the numbers/out comes were so close.


Screen shot of my Excel: (Nothing fancy, anyone can make it)

[Def]

The Z33 trans will accelerate faster 40-130 mph, but it's also going to add about 30-40 lbs to the car. Pretty much any 3 ratios that will have you topping out right at 130 will net the fastest acceleration there.


Honestly, if you keep killing gear boxes, I'd look at other stuff on your car. Your torque is right in line with most other T25 flange turbo setups on pump gas.

[logr]

I'm with Jacob on this one or maybe it's in your name. Ace in Hole was killing them too.
I parked a ZO6 with a blown M/C next to my 240.
Next time I went to drive my 240, the M/C was blown. coincidence????????????scary????????????Quit parking next to that Honda from next door.

Solid clutch and drop kicking might also do it, not that you do that. You drift?

[TSJ]

PPG helical gearset?

http://www.ppgearbox.com.au/page.asp?productid=63

[CodyAce]

The Z33 trans will accelerate faster 40-130 mph, but it's also going to add about 30-40 lbs to the car. Pretty much any 3 ratios that will have you topping out right at 130 will net the fastest acceleration there.

See that's still my personal debate. It seems like a 4.08 on the Z33 trans will actually be faster than what I have now.

Honestly, if you keep killing gear boxes, I'd look at other stuff on your car. Your torque is right in line with most other T25 flange turbo setups on pump gas.

Point out other 330 ft lbs setups that track 5-6 times a year and I'll look elsewhere. Engine is fine, clutches are fine, differetnail is perfect. I think the fact I engine break the car a lot may help reduce life...or the fact that the used transmissions I get are already ****.

JWT FUll Organic Clutch, JWT Flywheel, Steel Driveshaft etc etc...yet the transmissions end up ****ed. I wish I knew why. I drag race twice or so a year, never street race.

Solid clutch and drop kicking might also do it, not that you do that. You drift?

That's teh thign, it's a fully sprung organic type clutch from JWT. No drifting ever, a few launches at Island or Englishgtown a year.

PPG helical gearset?

http://www.ppgearbox.com.au/page.asp?productid=63

I never seem to break the gears, always always the secondary support (main/middle) bearings.

And at 4700 bucks I'd got a T5 setup