To all of those that have completed the swap.....

[slamdbusa]

What is your tach reading at 70mph? I would like to know, if the gearing is wrong or a six speed is needed.

VH45 and Z32 gearbox s13. Is the RPM's high like 4k or something or around 3k?

[SuperHatch]

What is your tach reading at 70mph? I would like to know, if the gearing is wrong or a six speed is needed.

VH45 and Z32 gearbox s13. Is the RPM's high like 4k or something or around 3k?

Well, assuming you are running a stock tire diameter of 24.6" and the stock rear end ratio of 4.08...

The 350Z 6 Speed will give you these RPMs - 5th - 1.000 - 3900RPM6th - 0.794 - 3100RPM

And the 300ZX 5 Speed will give you these RPMs - 4th - 1.000 - 3900RPM5th - 0.752 - 2900RPM

So adding a 6 Speed will actually raise your cruising RPM, not lower it. If your RPMs aren't where you want them to be, consider changing out the rear.

A 3.69 will give you 2650RPM @ 70MPH in 5th gear (Z32 box)A 3.54 will give you 2550RPM @ 70MPH in 5th gear (Z32 box)

FWIW, the engine has absolutely no impact on your cruising speed. You could have a lawnmower engine and the figures would be the same, except for the fact that the car couldn't go this fast.

[elwesso]

are you still using the stock 4.08 diff?

[T45]

Ouch, I may have to re-consider using the Q diff in my Z.

I bet your 240 gets off the line quite nicely now though!

[slamdbusa]

are you still using the stock 4.08 diff?

I am using the stock diff. So the RPM's should be at 3k, that means my tach is way off. What is the ratio on the 300zx and Q45 diffs?

Ouch, I may have to re-consider using the Q diff in my Z.

I bet your 240 gets off the line quite nicely now though!

Yes this thing just pulls like crazy. I am running an open diff right now, and last night I wanted to see if the one wheeler peeler would happen, and to my surprise both of the tires lit up.
Modified by slamdbusa at 11:09 AM 2/6/2008

[Mettler]

Running a 4.375:1 in the Skyline... didn't have tacho hooked up though, but it had insane bottom end from the word go, with a top speed of 246kmh @ 7500rpm in 5th.

[mtcookson]

You do need to recalibrate your tachometer for the new V8 signal. I believe you can actually take apart the stock tach and do this.

[craigztoyz]

Thre was a post a month ago about this. Topic was called Tach wiring or tach problem, something like that.

[slamdbusa]

I saw that post, I already did that, but I have no way of making sure if it is dead on.

I don't know because of when I get on it, the RPM's go up to and past the 8k on the stock KA tach. but at Idle, it sits around 900ish. I assume that this is close to it but not dead on, that is why I would like to know what the others have for theirs at 70mph.

I liked all the gearing specs, so that tells me that the engine just sounds like it is at 4k at 70. I'm just not used to it I guess, lol.

On another note what exhausts are you guys running? True duals with an X or H pipe, what size, does it need to follow the setup for the Cobra's exhausts?

[Mettler]

1.3/4" runners to 3" collectors, dual 3" flexijoins, dual reducers to 2.1/2", 2.1/2" X pipe (summit racing), dual 2.1/2" pipe all the way out the back to dual Flowmaster Super 44 mufflers

[craigztoyz]

Im going with dual 2 1/2 the whole way back, high flow cats, i have flowmaster 40's, and am getting an equilizer tube. should be pretty smooth tone

[tmorgan4]

I saw that post, I already did that, but I have no way of making sure if it is dead on.

I don't know because of when I get on it, the RPM's go up to and past the 8k on the stock KA tach. but at Idle, it sits around 900ish. I assume that this is close to it but not dead on, that is why I would like to know what the others have for theirs at 70mph.

I liked all the gearing specs, so that tells me that the engine just sounds like it is at 4k at 70. I'm just not used to it I guess, lol.

On another note what exhausts are you guys running? True duals with an X or H pipe, what size, does it need to follow the setup for the Cobra's exhausts?

I think the best way we can double check tach signal is to either use a high end timing light with an LED RPM readout or hook up to the consult system.

[T45]

There is another way with a multimeter if I can remember. I think you measure the tach wire with the meter in AC voltage mode and put red on tach and black to ground and it should tell you what the rpm's are. It was something like that. I used to do it back when I hooked up remote starts when they first came out. I don't know how accurate it is but I remember it being pretty close.

And I'm running the stock Z piping to an aftermarket cat-back. I think it's 2.25". I think the Q also uses 2.25" in it's stock system.

[slamdbusa]

I think the best way we can double check tach signal is to either use a high end timing light with an LED RPM readout or hook up to the consult system.

I don't have one of those timing lights, and I would have to pull out the wire diagrams again to find the Consult wires, lol.

[slamdbusa]

There is another way with a multimeter if I can remember. I think you measure the tach wire with the meter in AC voltage mode and put red on tach and black to ground and it should tell you what the rpm's are.

I give it a shot, I was thinking on using a GReddy turbo timer from the last set up, but I forgot that you still have to program the RPM's, D'oh.

[tmorgan4]

I might end up buying one of those lights mainly for this purpose. Chip in a 20 and you won't have to dig out your consult wires!

[SuperHatch]

I am using the stock diff. So the RPM's should be at 3k, that means my tach is way off. What is the ratio on the 300zx and Q45 diffs?

Stock Z NA = 4.08Stock Z TT = 3.69Stock Q45 90-96 = 3.54Stock Q45 97-01 = 3.69

Yes this thing just pulls like crazy. I am running an open diff right now, and last night I wanted to see if the one wheeler peeler would happen, and to my surprise both of the tires lit up.

They'll both light up in a straight line, for a little while anyway. Try punching it going round a turn and the inside tire will go up in smoke...

[slamdbusa]

They'll both light up in a straight line, for a little while anyway. Try punching it going round a turn and the inside tire will go up in smoke...

Yes they will, lol. I have a welded diff waiting to go into it.