Guest JAMIE T Posted January 4, 2005 Share Posted January 4, 2005 I'm checking into my rear end options. It is the only area of the car that I've put off digging into so far. I have a line on a ZXTT R230. I think they have a 3.69 ratio, VLSD. I'd like to use it. But, if it is too much gear or not enough, let me know what has worked for you! Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 4, 2005 Share Posted January 4, 2005 What is the tranny gearing? Also, how tall are those mondo 18inch tires your spinning? Mike Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted January 4, 2005 Share Posted January 4, 2005 I'm unsure of the gear ratio's in the tranny. It has aftermarket close ratio gear sets. The tires are just under 26" diam. The thing is, these engines typically see the plus side of 8K rpm, especially with cams. The power band could be as high a 5K-9K depending on cams and turbo(s). That is the reason, I posted this in the RB forum, otherwise if this were a more common application, I would have posted it in the drivetrain forum. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 4, 2005 Share Posted January 4, 2005 I ran 25.2" tall tires on my 240Z and had a .87 overdrive 5th gear. Top speed was about 145 at redline (7,500 rpm) in 5th with a 4.38 rear gear. For a street version of my car I would most likely run a 3.90 or a 4.11 rear gear unless I spent a lot of time on the highway. Then a 3.70 rear gear would be preferred. Quote Link to comment Share on other sites More sharing options...
Guest Aguyandaredhead Posted January 5, 2005 Share Posted January 5, 2005 Given you do have the OS Giken CR gear set in your tranny I would recommend the 3.54 from the R230ls from a Q45. I know I know some say the Q has a R200 but I have taken mine apart for powder coating and have measured it my self and can say for sure is is of the 230mm variety. A turbo car will respond and come ON-BOOST much better with the 3.54 than the 4.11 from a 300zxTT which is the gear I remember them having. When and If you start to fab mounts for the R230 let me know I can send you some pics of how I did it and it is isolated from the mounts with a fer of the Energy Susp bushings from the R180 bar with a new cradle for using the factory attachment points.. Jeff Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted January 5, 2005 Share Posted January 5, 2005 300zxTT had a 3:6 I belive.... Quote Link to comment Share on other sites More sharing options...
mjfawke Posted January 5, 2005 Share Posted January 5, 2005 Assuming you are running similar diameter wheels to stock, I would run a 3.9 with a CR gearbox. The stock GTR/GTST turbo boxes are ~3.3:1 1'st and I would assume the CR gearset would be approximately the same as the L series CR box (2.96:1 1'st). Having run both a 'B' CR box and now a RB20DET box, I can say that the 3.7:1 was too short for the CR box and a 3.9:1 would have been a better choice. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted January 5, 2005 Share Posted January 5, 2005 Yep, I'm pretty sure the ZXTT diff is 3.69, not 4.11. The 4.11 diff is what the NA cars came with, and it is an R200. I'd like to use the R230 for it's strength, we'll see what happens I guess. My other option is solid rear axle, which I didn't want to do. Quote Link to comment Share on other sites More sharing options...
Guest Aguyandaredhead Posted January 6, 2005 Share Posted January 6, 2005 You are correct, in my haste to answer this post I was not in a position to look at my notes on this subject. The 4.11 is the NA variety... My bad.. Jeff Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted January 6, 2005 Share Posted January 6, 2005 Struck a deal on a genuine 300ZXTT rear. It is FOR SURE an R230. It will come with the shafts. So, it looks like that is my choice as of right now. Quote Link to comment Share on other sites More sharing options...
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