Z32_5.3

I have a semi built 5.3 with stage 2 turbo cam, 80lb injectors, 525pump, twin gt35s intercooler with meth. No e85. Expecting 7-800rwhp.

right now car is 5spd out of a Nissan 300zx. They have plenty of 700hp builds on them stock. The rear end will either be 3.69s or 3.45s? Still debating as the 3.69s go in much easier but was told the 3.45s will make the car much more usable.

i don’t do much at the track, maybe that will change when car is done but right now I’m expecting to do weekend driving and around town driving on it mainly. I do plan to be cruising on highway a lot and doing 40+ mph rolls

local builder that very well known on a ton of high hp car will build me a t400 with a brake on it for 2k. Should I go that route? I have 1 experience with a auto trans and it was a t400 built manual valve body on a 383 procharged motor. The thing was sick and shifted instant. Was pretty insane to feel the torque etc always there.

Michael Yount

iTrader: (1)

Only you can decide what type (manual vs automatic) of transmission you prefer in your car. I think you'll be geared WAY to short with that tranny and either of the rear gears you mentioned. And I'd be surprised if that manual is gonna hold up behind 800 whp if you have traction.

Z32_5.3

To short with the 5spd correct? Everything now is new and custom so it’s worth money, until I toast clutch and potentially break trans. So I’m considering doing the auto. I just don’t wanna lose my highway driving. Cruising at 70 to the track 3 hours and doing highway pulls. Don’t want my mph to be limited.

Michael Yount

iTrader: (1)

What rear tire diameter? You trap in 4th gear I presume? What are your 4th and 5th gear ratios? This the CD009 tranny, right?

Z32_5.3

Tire size is 25.83

trans is following: RS5R30A
1st = 3.21
2nd = 1.92
3rd = 1.30
4th = 1.00
5th = .75

i have 3 option for the diff
3.69
3.45
3.13


Car isn't tuned yet so never did any driving on it. Will having a 3.13 gear slow it down a lot?

Michael Yount

iTrader: (1)

What rpm through traps -- or rpm limit for top end pulls?

At 6500 in 4th you're at 135 mph with the 3.69's. I'd think 800 rwhp has the potential to trap significantly higher than that.
The 3.45's will get you to 144.

Top end in 5th at 6500 with 3.69's - 180.
Top end in 5th at 6500 with 3.45's - 193.

At 70 mph with 3.69's - 2500 rpm
At 70 mph with 3.45's - 2400 rpm

I was thinking of the 6 spds -- they have shorter 1st, 2nd, 3rd gears than this one.

Based on all this - if 800 rwhp is real, I'd go 3.45's.

I didn't run the 3.13's....but can if you like. Just give me an rpm.....

Z32_5.3

I don’t think I’d go above 160 often but I would like to be capable of higher than that.

im using a calculator online and it says with 3.15s on my size tire at 75mph I would be about 3060 rpm. What is the final drive for th400 ? 1.00?

Michael Yount

iTrader: (1)

I think something's wrong with that online calc or the way you're using it -- I get 2300 rpm in 5th with 3.15's.

I need your rpm limit to calc traps and top speeds.....

Z32_5.3

The 3.13 on calculator with 1.00 final on th400 says 166 at 6800rpm. Not sure what my 5.3 would do rpm wise but should do that I would think. I don’t think I’ll hit 166 in the 1/4. That would be pretty awesome.

cruising at 75 is about 3060 rpm. Doesn’t seem to bad considering alternative of clutch buying and breaking 5spd trans. Car I would hope is much faster on the th400 manual valve body.

never driven on something with such a long gear. Wonder if that’s going to stress everything. I’ll have to do some googling.

Z32_5.3

I would prefer to go th400 honestly. If I can get car to cruise at 75 with reasonable rpm and can get to 165 top speed would also be great. So all the calculations I did was the 1.00 on th400

rpm limit, idk. It’s got arp hardware all around motor, .030 over pistons with factory resized rods gen 3. For bottom end. Has cam, btr hardened push rods, btr dual titanium valve springs, btr steel retainers and valve seats.

Z32_5.3

Michael Yount

iTrader: (1)

Top gear should be 1.00 on the 3 speed auto. Makes the calcs easier. With the 3.13's, 6500 rpm, and 5% converter slip --- top speed is 152; and that means 76 mph will be 3250 rpm. If you're serious about zeroing in on speeds -- you'll need realistic rpm estimates and you'll need to know how much converter slip you'll have. Good luck.

Z32_5.3

Thanks for taking some time to go back and forth. I know I need some more info. The car is getting piping welded and then it’s pretty much winter time. So I wasn’t even going to run the car at all 5spd if I could get more details on just doing th400. The custom 5spd kit would let me about break even on a built th400 and I would just have to pay for a converter and driveshaft.

seems like I have to start just driving speed limit on highway to keep rpm down though. I’ll lookup what 150 trap is in 1/4 mile and I prob won’t run that quick albeit. Highway run from 40-150 should be enough too.

yeah the car is 3300lbs , says 142 is a 9.5 in 1/4. I don’t think I’ll ever run that lol. I’ll have the power and setup to but doubt I’ll get the car to track standards and tires and my driving skill

Michael Yount

iTrader: (1)

No problem - with chassis and traction, and that much power/torque, you might consider going a bit longer than the 3.15's, especially with a bit more converter slip. Of course, if you have room, you could always fine tune with a bit taller rear tire.

Z32_5.3

If I got the car tuned on the stand 5spd, I would need a retune for the th400 correct?

Michael Yount

iTrader: (1)

I would want the tune done with the final combo you're gonna be running. With the auto/converter, the way the motor loads the rearend/chassis is very different than with a manual. Be patient, take your time -- get the tune done with the auto if that's where you're going.

Z32_5.3

i don’t think I could get bigger tire. So would have to just work on the gearing. This ain’t my car in picture but I’m copying his tire/wheel setup