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240Z using RB26 motor & RB25DET 5 speed


Mike Rowe

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(a) I have just purchased a 240Z, an R32 RB26DETT half cut and an R34 RB25DET 5 speed which I intend to splice together.

I want to purchase an appropriate LSD with the best all round ratio for this combination. The car will be used for tarmac rallies, hill climbs, track work and the odd amateur drag day. Can anyone who has done the same conversion help please? (I was thinking around 3.5 what's your thought?)

 

(B) The half cut has R32 GTR disk and calipers. Can these be adapted on to the front of the 240?

 

© I would also appreciate any other advice on engine & gearbox mounts

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(a) I have just purchased a 240Z' date=' an R32 RB26DETT half cut and an R34 RB25DET 5 speed which I intend to splice together.

I want to purchase an appropriate LSD with the best all round ratio for this combination. The car will be used for tarmac rallies, hill climbs, track work and the odd amateur drag day. Can anyone who has done the same conversion help please? (I was thinking around 3.5 what's your thought?)

 

(B) The half cut has R32 GTR disk and calipers. Can these be adapted on to the front of the 240?

 

© I would also appreciate any other advice on engine & gearbox mounts[/quote']

 

On finding a good all around ratio, all of those seem like pretty wild ends of the spectrum meaning I don't think professionally they would use similar gears for all those events.

 

I would say you're in an order of a 4.11 though, but the other guys on this forum have way more knowledge than me.

 

I honestly hate to do this to ya, but please use the search function.

http://forums.hybridz.org/search.php?

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I'd say a 3.9 or 4.11 would be ideal. I'm still debating myself which to go with. My car will be mostly street driven with the occasional drag. (Up the Boulevard:-D ) The 3.9 rear, I think, will give me more flexibility, but the 4.11 will give me a faster 1/4 mile time. Ahh decisions, decisions.

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I am running an R200 with a 3.9 ratio from an '88 200SX. The GT-R had a 4.11, and the GTs-T five speed had a 4.38 I believe. The way I saw it though, all of us are running cars that are easily five hundred pounds lighter than either of those. You really are not sacrificing any performance by going with a lower ratio. In fact, the reason I went with it is to give a decent freeway cruising engine speed. To be honest, I think a 3.7 or 3.5 would be the best overall. I had a 3.5 in my last turbo 240Z and it was beautiful. On that note, I still have two 280ZX turbo 3.5 R200 diffs if anyone is interested. I'd let them go real cheap. A friend also has an Nismo R180 L.S.D. 4.11 sitting over here that is for sale for $700.

Brian

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If you don't like the gearing you got, you could always change it. It's not like the diffs in our cars are hard to change (maybe for some). And Nissan makes plenty of gears in R180 or R200 form.

 

I say keep a few spares and see how that works out for ya. I've got my R200 3.90 Backup waiting for me incase I blow up the R180.

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Guest JAMIE T

I think I remember Matt saying he recently installed a ZXTT 3.69 ratio rear in a RB26 car and it was a major improvement in the way the car accelerated. He might not chime in here since he's been real busy lately. Try searching on the subject and you'll probably find it. It might be int he drivetrain forum or the RB forum. I can't remember. But, anyway it helped me decide to go with the R230 diff I had already purchased and now the install is going pretty well.

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Thanks everyone for your help. I'm new to this forum thing & it is fantastic.

Sounds like the 3.9 is a good medium way to go.

Can I ask if anyone knows - there are short & long nose diffs - presumably the long nose is heavier so sounds like the short nose is better to use for weight reasons? It also sounds like the shorter nose are out of more modern cars as well?

(1) My question - is it better to use a short nose out of a modern 200Sx or something?

 

(2) no one has commented on whether I can adapt GTR brakes to the 240Z?

 

(3) Can anyone help with engine mounts & gearbox mounts - does anyone supply adaptors or not?

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(1) My question - is it better to use a short nose out of a modern 200Sx or something?

Short noses might be more available, but you'll have to custom mount it. The long nose R200's you can use hardware out of the 280Z (I'm not sure which car you are using)

 

(2) no one has commented on whether I can adapt GTR brakes to the 240Z?

You can adapt any kind of brakes you want, just as long as your skills enable you to do so, most likely will be custom mounted which you might have to figure out on your own, or search for this topic in the "Brakes" forum

 

(3) Can anyone help with engine mounts & gearbox mounts - does anyone supply adaptors or not?

I can grab you some motor mounts, but if you want a transmission mount, I might be able to supply you one if your car is a 240Z.

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Thanks everyone for your help. I'm new to this forum thing & it is fantastic.

Sounds like the 3.9 is a good medium way to go.

Can I ask if anyone knows - there are short & long nose diffs - presumably the long nose is heavier so sounds like the short nose is better to use for weight reasons? It also sounds like the shorter nose are out of more modern cars as well?

(1) My question - is it better to use a short nose out of a modern 200Sx or something?

QUOTE]

 

If you have a Long nose diff in your car now I would get a Long nose out of later model Z 87-89 12mm, and then get the appropriate gear set for it. It will make life a lot easier, and it's almost a bolt in procedure.

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(3) Can anyone help with engine mounts & gearbox mounts - does anyone supply adaptors or not?

I can grab you some motor mounts, but if you want a transmission mount, I might be able to supply you one if your car is a 240Z.

 

Thanks 240ZMaster - yes the car I have is a 240Z. I have bought them from the other side of Australia, so the car and a GTR R32 halfcut are being transported currently to Western Australia. When I get them and can check out whether I can cut out the mounts from the GTR and mould into the 240Z or not I may take you up on your offer re the mounts and also the gearbox mounts (I have an R34 DET 5 speed box coming as well.) Th e engine mounts and gearbox mounts you use, is there a photo of them anywhere?

regards Mike Thanks 260Z for your message as well

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(3) Can anyone help with engine mounts & gearbox mounts - does anyone supply adaptors or not?

I can grab you some motor mounts' date=' but if you want a transmission mount, I might be able to supply you one if your car is a 240Z.

 

Thanks 240ZMaster - yes the car I have is a 240Z. I have bought them from the other side of Australia, so the car and a GTR R32 halfcut are being transported currently to Western Australia. When I get them and can check out whether I can cut out the mounts from the GTR and mould into the 240Z or not I may take you up on your offer re the mounts and also the gearbox mounts (I have an R34 DET 5 speed box coming as well.) Th e engine mounts and gearbox mounts you use, is there a photo of them anywhere?

regards Mike Thanks 260Z for your message as well[/quote']

 

I just improved my mounts slightly. I will have the photos of them up within this week. I plan on dropping in my motor soon and will have the photos that go with it!

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Vspec or STD R32?

 

The STD have the same calipers as the Z32 although the mounting for the rotors is a bit different.

 

I believe the 240Z has the same front brake setup as the '71 "Hakosuka" Skyline. I just recently purchased one of these cars and it has a GTR front brake conversion (I also have an R32 so I recognized the calipers immediately). As soon as I receive it from the dealer, I'll take some pictures on the conversion and post them for you.

 

Unfortunately, the rears are still drum....not sure if I want to mess with that or not.....

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Actually, the Hakosuka does not use the same front brakes as the S30 Z. I found this the hard way when I tried to use a Z car kit on my Hakosuka. The Z uses a larger diameter disk than the Skyline. By about 3/4 inch or so. While the rotor and hat are interchangeable, the caliper will require a different bracket.

 

Brian

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Vspec or STD R32?

 

The STD have the same calipers as the Z32 although the mounting for the rotors is a bit different.

 

I believe the 240Z has the same front brake setup as the '71 "Hakosuka" Skyline. I just recently purchased one of these cars and it has a GTR front brake conversion (I also have an R32 so I recognized the calipers immediately). As soon as I receive it from the dealer' date=' I'll take some pictures on the conversion and post them for you.

 

Hi thanks very much for your feedback on the brakes. I would appreciate photos of the conversion. The R32 brakes would be standard GTR not V spec I would think. I have a photo but I cant seem to put it in here, I ll try sending it to you for identification

 

I'm not sure what a Hakosura Skyline is - is it a special race model?

regards Mike

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Actually' date=' the Hakosuka does not use the same front brakes as the S30 Z. I found this the hard way when I tried to use a Z car kit on my Hakosuka. The Z uses a larger diameter disk than the Skyline. By about 3/4 inch or so. While the rotor and hat are interchangeable, the caliper will require a different bracket.

 

Brian[/quote']

 

Brian thanks. Are you saying that the GTR rotor & hub (is that the hat you refer to) fit on the axle of the 240Z but as the GTR rotor (disc) is smaller than the 240Z disc (hard to believe) that the caliper then does not bolt up in the correct place? Regards Mike

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Sorry, I may not have been as clear as needed. I was simply referring to the comparison between an S30 Z car and a Hakosuka ('69-'72) Skyline. Those used different diameter rotors but use the same hub bearings, therefor making that part interchangeable. The GT-R that is being discussed is a much later R32 ('89-'93) model. That one is not interchangeable in any easy way. Due to it's four wheel drive configuration, the front hub/rotor does not connect in a simliar fashion. The rotor can be used, but will need a special hat assembly to bolt onto an S30 compatible hub.

Brian

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I saw the question on the brakes above and gtr compatibilty.

 

heres what i did. Im using z31 rotors and z32 calipers.

 

http://forums.hybridz.org/showthread.php?t=82357

 

http://forums.hybridz.org/showthread.php?t=71077

 

http://forums.hybridz.org/showthread.php?t=70957

 

http://forums.hybridz.org/showthread.php?t=94123

 

Since a common mod among the Z32 guys is gtr rotors and calipers im pretty sure with what i did above the gtr brake swap should be a bolt on upgrade. may require a shim or two here and there but should still work.

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Brian...thought it was you:) I go by GTR2.7L on most of the other sites....Thought Hakosuka would be more appropriate. Thanks for the correction on the Hakosuka vs Z brakes.

 

Mike, a Vspec/II cut would have calipers that say "Brembo" on them. If they say Nissan, its a STD cut. These are the same calipers as on the Z32's....

 

Stony....Despite the calipers being the same (and taking the same pads fore and rear), the front Z32 rotors won't work on a STD R32. As I recall, the bolt radius is slightly off which would preclude the vice versa. Rear Z32's work just fine for a GTR rear....

 

Its a shame really....it cost me 38 bucks a Brembo rotor for the rears on my 32 in the states....but I would have had to order the same rotors from Japan for the front at a SUBSTANTIALLY higher price and wait two week for them to show up.

 

Hawk Plus pads are the same for both cars, front and rear though.

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