melfice_mx Posted March 31, 2014 Share Posted March 31, 2014 What would be best overall Differential gear ratio for 240z with SBC (350-400 HP) and 700r4 with 2800 Stall? Currently have R200 4:11 and gears are WAYY too short.. Looking for balance between launch/freeway RPMs.. Any suggestions? Would it bog down too much at launch with 3:54 (already have) ? Any input appreciated! Thank you, Quote Link to comment Share on other sites More sharing options...
jhm Posted March 31, 2014 Share Posted March 31, 2014 I would think you'd be fine with 3.54 rear end. The first gear ratio on the 700-r4 is plenty low (3.06), especially considering the 240's light overall weight. Quote Link to comment Share on other sites More sharing options...
melfice_mx Posted March 31, 2014 Author Share Posted March 31, 2014 Thanks!! I will install Diff on weekend Quote Link to comment Share on other sites More sharing options...
leroylucky Posted March 31, 2014 Share Posted March 31, 2014 Let us know what you think. I have the same 4:11 set up and need to redo the trans. Quote Link to comment Share on other sites More sharing options...
skerry Posted April 1, 2014 Share Posted April 1, 2014 (edited) I have a chart for this, it won't let me upload though. Give me your tire size and I can give you info on both diff's. For my 225/50 16, at 4.11 runs 70 mph at about 2800 rpms while 3.54 runs 70 mph at 2300 rpms. Edited April 1, 2014 by skerry Quote Link to comment Share on other sites More sharing options...
melfice_mx Posted April 1, 2014 Author Share Posted April 1, 2014 I have 225/55 15 - at 4.11 runs 70 mph at around 3300-3500. Will be swaping this weekend hopefuly. Will update with details after swap. Thank you. Quote Link to comment Share on other sites More sharing options...
skerry Posted April 1, 2014 Share Posted April 1, 2014 Hmm, are you sure you don't have a transmission problem? 3300-3500 makes sense for 3rd gear but you might have a bigger problem with that in your final gear. As silly as it sounds, are you also sure that it's a 700R4? I ask because I was sold a car with a Powerdrive only to find out it had a Turbo 350 in it. The guy wasn't feeling the first shift and assumed it was only shifting once. According to the numbers, the 3.54 gears should put you at 2200rpms but that assumes you don't have another issue. Thanks Stephen Quote Link to comment Share on other sites More sharing options...
melfice_mx Posted April 1, 2014 Author Share Posted April 1, 2014 It is an 700R4.. 100% about it.. 4 speed 700r4.. And Trans is rebuilt with no issues - 2800 Stall Thank you. Quote Link to comment Share on other sites More sharing options...
johnc Posted April 1, 2014 Share Posted April 1, 2014 Remember, there is no best on hybridz. Quote Link to comment Share on other sites More sharing options...
melfice_mx Posted April 1, 2014 Author Share Posted April 1, 2014 By BEST i meant most recommended.. based on experice by fellow S30 V8 owners Quote Link to comment Share on other sites More sharing options...
78zstyle Posted April 2, 2014 Share Posted April 2, 2014 By BEST i meant most recommended.. based on experice by fellow S30 V8 owners Which of course depends on the intended purpose of this vehicle. Drag racer? Cruiser? Quote Link to comment Share on other sites More sharing options...
melfice_mx Posted April 2, 2014 Author Share Posted April 2, 2014 Weekend Driver and track once every couple weeks/months .. I want to be able to drive on stree/freeway and take to track making decent times... Is it too much asking? lol Quote Link to comment Share on other sites More sharing options...
Ylo73z Posted April 6, 2014 Share Posted April 6, 2014 I'm looming for a r200 with 4.11s let me know if you want to sell those once you change gears Quote Link to comment Share on other sites More sharing options...
melfice_mx Posted April 7, 2014 Author Share Posted April 7, 2014 Ylo73z.. I will be selling my 4.11 diff in 1 or 2 weeks after changing to 3.54... Or trading for good condition fenders/hood .. Make me and offer.. I'm also in San Diego area Quote Link to comment Share on other sites More sharing options...
Eric JB Posted May 22, 2014 Share Posted May 22, 2014 (edited) 406/700r/3.54's here. I have 235 60 15 drag radials.(pretty close to 26 inches) In third gear at 5k, I'm at about 108mph. I don't have a speedo, so that is off the timeslip. www.wallaceracing.com/Calculators.htm is a good source for gearing calculators. Edited May 22, 2014 by Eric JB Quote Link to comment Share on other sites More sharing options...
kegomatix Posted June 5, 2014 Share Posted June 5, 2014 I'm looking to do the same thing... 700R4 rebuilt about 2500 miles ago, about 3 grand at 65 MPH. I did a mpg on it last tank and I got a mixture of 21 city/hwy and getting on it pretty hard half of that time. I would like to improve the mileage a little more and imagine lowering that rpm range at highway speeds would help out. Quote Link to comment Share on other sites More sharing options...
Ylo73z Posted June 8, 2014 Share Posted June 8, 2014 Get a gear vendor Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted July 1, 2014 Share Posted July 1, 2014 (edited) your obviously going to need to consider tire diameter, rear gear ratio and transmission gearing, generally your want the first gear in the transmission multiplied times the rear differential gear ratio to fall in the 10:1-10.5:1 range and cruise at a bit higher rpm that the torque converter stall speed in 1:1 gearing, if you have a over drive gear having a lock-up converter sure helps and a trans fluid cooler is almost mandatory if you have a high stall speed torque converter you should ideally select a cam , tire diam. converter stall speed and differential gearing that put the engine rpm range in your power curve about 90% of the time http://forum.grumpysperformance.com/viewtopic.php?f=71&t=741&p=1048#p1048 Edited July 1, 2014 by grumpyvette Quote Link to comment Share on other sites More sharing options...
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