What's the highest gear ratio for R200 or other strong rear?

[Guest Magnum Rockwilder]

I'm looking for an extremely lazy rear end for low rpm operation with a 3spd auto tranny. What's the best choice for a rear end that will handle a shitload of power but has a high (numerically low) rear end ratio? I'm looking for something in the 2.50-3.25 range... does it exist?

[Guest Aaron]

I think Scottie said the vette rear he used was a 3.07. I have heard the Ford 8.8 has gears available in the 2's.

[Guest Magnum Rockwilder]

I'm specifically looking for a bolt-in Z R200 or similar rear. I don't want to get into too much fabrication to mount a different rear. Thanks for the input, though.

[Scottie-GNZ]

From the factory, it is 3:36 and it is very rare and treasured. NISMO does have a taller set but bring a jar of vasoline when you go to pay for it. before you consider spending that kind of $$$, look into a tranny with OD and converter lockup as another option.

[Guest Magnum Rockwilder]

Thanks, Scottie.

 

I'm looking for a high rear gear because I'm seriously considering putting my Cad 500 in one of my Z's, after all the conversation in "the other thread". The stock Caddy valvetrain floats at... get ready to crack the **** up... 4200rpm, and flies apart at 4500. I can get a shaft mounted rocker system that's good for 5500rpm, but it's a little expensive and I wanted to just drop in a stock 500 to begin with... to get baseline performance numbers.

 

I don't know if a 700r4 or 2004r can hold up to the 500tq of a stock 500, let alone the 600+ of a built 500... and even if I could get a OD built to handle the power, I don't know if I could afford it. A freakin stall converter for a 700r4 is 3 times the cost of one for a TH350/400. AND I planned on putting a pretty good sized shot of spray on the stock 500, so that ups the ante. I'd like to use a TH400 and lazy rear gear, then if I like the setup and still want to drop the RPM's more, I could later add a GearVendors Overdrive when I win the lottery and can afford $2500 for one.

 

I'll do the math and see if the 3.36 would cut it. If not, I'll have to built a OD tranny and keep a spare on hand.

 

What do the 3.36's come in? The local salvage yard is loaded with Z's and other Nissan/Datsuns, so they may have one.

[80LS1T]

What makes you think a R200 will hold up to that much TQ/HP? I think most guys say the R200's limit is high 400's-500HP. If your going with a 500 caddy then I would suggest the R230 set up. there is probably(I have no idea?) a few more choices for the R230 than the R200 and its a lot stronger.

 

Thats just me though

 

 

Guy

[Guest Magnum Rockwilder]

I'll check into the R230. I've never heard of it, but if it's readily available and a close-to-bolt-on mod, I'm all for it. Thanks for the tip.

[Scottie-GNZ]

I was in the same boat you are in. My little 3.8L makes the power/torque you are referring to, i.e, 500+hp/600+ lb/ft torque and is not a high revver. As for the RPM issue, so what if it only revs to 4400. Take advantage of the power curve, gear accordingly and ignore those who think you have to have RPMs to make power. One thing you might consider to help the RPM issue is a little stiffer valve spring, but not so stiff as to wipe out the cam. This is a known problem in the Buick turbo world and not unusual to see an engine die at 5000 and pick up 100hp with just a fresh set of valve springs. Remember, Caddy was not thinking performance so those springs were probably dead after 10K miles.

 

Tough call on the tranny but w/o OD and LU and a 3.54 gear, you will get poor mileage on the highway and possibly put too much heat in tranny because of converter slip which will probably be 200-300 more RPMs @ 65mph over LU. Thus the tall gearing in that car. The R200 3.36 came in the 79 280ZX 2+2 with a 4-spd. Others have claimed it came in other models but that is unconfirmed. With the automatic your problem will be the axles not the R200 so going to a R230 buys you nothing except it guarantees a LSD. The highest ratio for the R230 is 3.54 anyway.

 

The dilemna I faced was finding a ratio that would allow me to trap at 135+ in 3rd. The NISMO gear, 3.06 if I recall, would have been perfect but at $600 + $400 for a used R200 LSD + $125 for the gear swap and new clutches + $800 for a pair of custom axles to withstand the abuse I would put on them + $800 for a spare pair being they are not even length and the C4 swap just made sense. I know you do not want to do that but I was just trying to make a point that the expense of the tranny option is not to be ignored.

[Guest Magnum Rockwilder]

I did the math, and with a TH400 and 3.36 gears, my top speed would be 97mph at stock redline, and with a 5500rpm built motor it would top out at 127mph. I don't even WANT to know where it would top out with any lower a gear.

 

With a 3.90 rear gear (which I have 2 of), and a 700r4, my top speed would be 120mph with a stock redline, and 156mph with a 5500rpm redline. With 3.70 gears it would be 127mph stock, and with 3.55 it would be 132mph.

 

It looks like OD is the only realistic option without swapping to a rear end that would allow me to use a 3.08 or higher.

 

I'll look into it, and I might decide to just use a SBC, but I'd like to give the 500 a try just to see how it pulls.

 

I saw you over on the V8 RX7 board, by the way. I have 2 2nd gens with Granny's kits.

[Brad-ManQ45]

Don't forget that good axles are available for the R230 swap now...and you can have a 3.36 or 2.9x ratio in the ones from an Armada.

[Guest Magnum Rockwilder]

I don't really want to get into too much fabrication and hard to find/expensive parts like an R230. If I wanted to fabricate, I'd just install a 4-link rear suspension and Ford 9" rear. I don't see the point in spending a lot of time and money working on a Nissan 9" (230mm) rear when I could easily get a Ford one with better aftermarket support and a proven reputation.

 

I think I'll just look into building an OD tranny and look for a 3.55 R200 rear.

 

Thanks for all the input.