rb26 MOTOR/350Z TRANS ??

[74260zt]

I'm throwing this out here for your responces. I have two 350z trans, and one rb25det trans, and one rb25det bellhousing.

My hopes are to make a 350z trans bolt up to my rb26 motor, either by using the extra bellhousing, and cut and grafting it together, or have a adaptor plate made.

Has anyone heard of someone mating up the 350z 6 spd to a rb block??I've already heard the usual "why don't you just use the rb25det trans like everyone else?" Well, I've always wanted to be different, so this is now my quest.

Any one have any input on this, other than negative remarks? I think this is a pretty cool idea, to have a Nissan 350z 6spd behind my rb26 zcar.If you've ever examined one of these trans, you wouldn't have any doubts about it being strong enough... the thing is beefy...

[IvoryJ30t]

i have never seen one in person, and cannot speculate on the shaft spacing, or case configuration.

[74260zt]

The input shaft has the same spline count, and same size as the rb trans (which by the way is the same as my z car trans).

My main question has to do with the bolt pattern of the block. That is what I need to change to make this work. Everything else is doable...

[IvoryJ30t]

well, the rb26, rb25, and vg30dexx use the same transmission.

the differences are in the single piece frontcase/bellhousing, and the case lengths. also the AWD T case on the 26. the gears, synchros, and ratios are identical.

the Z32 trans will bolt up to an rb if you take the rb26/25 front case/bellhousing and bolt it to the Z32 trans.

if the front case will bolt to the bearing plate of the Z33 trans, your good to go. if i saw what the new 6 speeds looked like i would be able to say.

what are the gear ratios of the 6 speed?

[IvoryJ30t]

i did the math and figured the Z32 trans is perfect for my application. with an 8k redline, a 3.916 rear, and a 255/40-17 rear tire-

at 8,000 rpm-1st- 40 something mph2nd- 80 mph3rd- 121 ish4th- 1565th- 202

thats not exact, just off the top of my head.

[74260zt]

I've already compared the front half exchange, no way... I really don't have any idea of the gear ratios yet, but I will by the end of this eve.

I will go outside and take some pics, so that you guys will have a better idea what I'm up against.Be back....

[74260zt]

OK, here goes. These are the pics of the 350z and the rb25det trans.



As you can see, the bellhousing is fairly the same size, so that should not be a prob.The other issue will be the shifter mech. It is 9" further to the rear, but has a removable u joint, and shifter mount.The throwout lever is on the oppisite side, but I think a McLeod hyd t/o will solve that issue.

Well.... whats your thoughts on this? I know some work will be involved in this swap, but hey.... thats what I like!! WORK

[IvoryJ30t]

unless you have some heavy console reconstruction plan, i dont know if its gonna be worth the trouble.

[74260zt]

unless you have some heavy console reconstruction plan, i dont know if its gonna be worth the trouble.

Can you see the ujoint knuckle thingie on the 350z? I think that can be shortened quite abit, and the console can/will be removed in favor of a custom one, or just carpet the tunnel....Whata ya think??

[IvoryJ30t]

the easiest way that i can think of is to have the flange surface of the bellhousing machined down and have an aluminum plate tig'ed to the transmission.

measure the bolt spacing around the rb, and the centerline of the crank. im sure a machine shop wouldnt have a problem making an adaptor plate.

[IvoryJ30t]

ive also heard stories of excessive roughness in those 6 speeds.

personally, i wouldnt even put the time into it, but if you want the 6 speed, a welded adaptor plate is probably the best bet.

[74260zt]

ive also heard stories of excessive roughness in those 6 speeds.

personally, i wouldnt even put the time into it, but if you want the 6 speed, a welded adaptor plate is probably the best bet.

Yea, me too, thats why I paid $250 for the first one, and $103 for the second. But hey.... even thats a deal to good to pass up....

[IvoryJ30t]

oh, i didnt know all that!!

i would take the front case off of it, and take the front case off the RB25 trans, and take them to a machine shop that can heli-arc weld [AC current tig]

[IvoryJ30t]

i wouldnt try to fab an adaptor plate up myself because any misalignment will kill the input bearing.

[NISMO_RB25]

I got to ask this question, How did you get them that cheap?

I have nothing useful to add to this thread, but I think it is an awesome idea. Can't wait to see pics of your progress.

[Nameless EJ6]

It's been done on the RB30 transmisssion:

http://www.geocities.com/psi_vl/photos.htm

I see no reason it won't work on any other RB....

[gabossie]

It's been done on the RB30 transmisssion:

http://www.geocities.com/psi_vl/photos.htm

I see no reason it won't work on any other RB....

That's a Z32/RB30 hybrid transmission. He is trying to work a Z33/RB transmission.

[Nameless EJ6]

O my bad! Should've read better.

Hopefully it it works, that would be gnarly...

[74260zt]

what are the gear ratios of the 350z trans?

350z trans gearing:

1st> 3:7942nd>2:3243rd>1:6244th>1:2715th>1:0006th>0:794final drive>3:538

[s13sr20chris]

fantastic idea! i have not been inside of the z33 m/t yet, but they look quite intimidating from the outside. i dont believe they will have very much part interchangability with the z32/rb trans. i think you should do this bro.

[IvoryJ30t]

i cant wait to see how this turns out. your probably going to want a Z32 tt rear to offset the short 6th gear.

[74260zt]

I drove a 350z yesterday and really liked the gears. They are very close ratio, but the prob is going to be in the rear diff gears.The 350z has a 3:54 diff in it, and I thought while driving the 350, it ran out of gear way to fast in the first 4 gears.

This was in a N/A, so I can imagine it will be worse in a turbo application.I have a 3:7 viscious lsd out of the Z31 SS Shirio model, so that will make the 350z trans gears even shorter....

I don't know much about how the rb26 power band is, so the 3:7 diff may be ok, sinse from what I hear, the 26 is a much higher revvvvr than the L6 I now have. I guess I need to go to that website that has that device where you can enter the gears, and it will show what rpm and speed each gear change will give you....

BTW, the guy that owned the 350 I drove, didn't have a clue that Nissan has been swapping out the trans in the first year model 350z, due to 3rd gear syncros. He wanted me to "get on it" while driving it, and I felt no probs with the syncros in his trans.... so... maybe the two 350 trans I bought, will hopefully be as his was... OK... (I hope anyways...)

later...joel

[Porschephile]

This was in a N/A, so I can imagine it will be worse in a turbo application.I have a 3:7 viscious lsd out of the Z31 SS Shirio model, so that will make the 350z trans gears even shorter....

Hehe, don't worry about it Joel. A 3.70 should be fine with your RB. At least you won't have a 4.11 R200 like me! Damn, I can't even imagine how quick the gears will go by with that! On top of that, I'm not even starting w/ a stock 26 and will be going w/ aftermarket twins and will have significantly more power. I don't mind the increased rpm when cruising, because the rb26 likes higher rpm anyways. At least, that's the excuse I'm using.

[IvoryJ30t]

is that an original nissan trans? those numbers seem very close to the ratios of the R34 getrag 6 speed.

if anything, i would imagine you can aquire the 3.545 R200 from an R34 GTR.

[74260zt]

is that an original nissan trans? those numbers seem very close to the ratios of the R34 getrag 6 speed.

if anything, i would imagine you can aquire the 3.545 R200 from an R34 GTR.

Yep... thats the gear ratios inside the oem 350z trans... I haven't seen the R34 trans numbers, so I can't compare them.

I have an extra viscious lsd exactly like the one I have in my ride now, so I guess if I need to step down on the numerical number of the diff gears, I could take a set of 3:54 ring and pinions out of a open R200, and install them into the viscious unit, to give me a 3:54 lsd...

Something tells me I'll be ok with the 3:7... we'll see...

[hatebobbarker]

someone in socal is trying it for an s14 rb25 w/ z33 transmission

[74260zt]

someone in socal is trying it for an s14 rb25 w/ z33 transmission

Do you have any more info on that subject? Can you slip me a contact address?? I'd like to compare notes.... :poke

thanksjoel

[hatebobbarker]

give me some contact info, my email is [email protected]

[Porschephile]

Is the whole point of this to get a 6spd? If that's the case, there are easier ways (although insanely expensive). I remember seeing a Z32 6spd gear kit by OS Giken. Now, I'm not sure what type of modifications this would require to a z32 gearbox, or whether it fits in the stock box. Though, if it fits the stock box you could probably use this gear set in your rb25 transmission, since they have the same gears. I'm considering an OSG 5spd gear set in the future just because I found it really cheap! Not like I would be making enough power to need it but, I'd do it just because I can.

[AREITU]

Is the whole point of this to get a 6spd? If that's the case, there are easier ways (although insanely expensive). I remember seeing a Z32 6spd gear kit by OS Giken. Now, I'm not sure what type of modifications this would require to a z32 gearbox, or whether it fits in the stock box. Though, if it fits the stock box you could probably use this gear set in your rb25 transmission, since they have the same gears.

It seems like it would just be cheaper to adapt a Z33 6-speed. It'd probably cost as much as a relatively new transmission to have the Z32 torn apart and reassembled correctly.

I'm considering an OSG 5spd gear set in the future just because I found it really cheap! Not like I would be making enough power to need it but, I'd do it just because I can.

Does it have synchros?