Rosco Posted November 21, 2014 Author Share Posted November 21, 2014 Just clicked on "quote" under your (johnc) post and typed a message, when I hit post it posted a blank. Look above this post and you'll see. Maybe somethings wrong with my computer. I have a mac Whatever… Quote Link to comment Share on other sites More sharing options...
Rosco Posted November 21, 2014 Author Share Posted November 21, 2014 Here's my dyno sheet. Rebello Built this motor for me a couple years ago. I'm running ITB's, Adaptronics ECU, 1 5/8" comp header, 3" exhaust Part of the problem is driver (ME) and the other part is gears. I need to run it up to 7,300-7,500 rpm's but the only time I ever get there is the back straight at VIR full and the back straight at Road Atlanta, Even then I'm still in 4th. I believe I've gotten my answer to my original question "Whats the best trans for an L28 280z track car" ANSWER: there is no "Best" anything it depends on driving style, HP and torque. Driving style is the main factor in this equation. I'm going to change out my rear gear to a 4.11 and see what I think. I'll let you know next year… See ya at the track! Thanks for all the help! Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 22, 2014 Share Posted November 22, 2014 Just clicked on "quote" under your (johnc) post and typed a message, when I hit post it posted a blank. Look above this post and you'll see. Maybe somethings wrong with my computer. I have a mac Whatever… I just did this on my Mac... Quote Link to comment Share on other sites More sharing options...
johnc Posted November 22, 2014 Share Posted November 22, 2014 I would never run that engine below 4,500 rpm on the track. Redline would be 7,500 with the shift light coming on at 7,300 rpm. A rough starting point on trans gearing would give you a 2,000 rpm drop from first to second, 1,750 second to third, and 1,500 rpm or less for every subsequent shift. The engine has a broad enough torque band to handle that. You should be able to keep the rpms up with your current gearing. In the video you are short shifting for some reason. Starting with the rear end gear is a good idea. Quote Link to comment Share on other sites More sharing options...
Rosco Posted November 22, 2014 Author Share Posted November 22, 2014 I would never run that engine below 4,500 rpm on the track. Redline would be 7,500 with the shift light coming on at 7,300 rpm. A rough starting point on trans gearing would give you a 2,000 rpm drop from first to second, 1,750 second to third, and 1,500 rpm or less for every subsequent shift. The engine has a broad enough torque band to handle that. You should be able to keep the rpms up with your current gearing. In the video you are short shifting for some reason. Starting with the rear end gear is a good idea. I just dropped the car off with John Hines for a rewire and cage install, hopefully we can come up with a good solution for gearing Thanks for your help Quote Link to comment Share on other sites More sharing options...
bjhines Posted November 22, 2014 Share Posted November 22, 2014 Looking at the torque curve, Generally speaking you want to shift "around the peak" ie. 5400@299ftlbs. For a 1500 RPM drop that would be shifting at 6500@282ftlbs which would drop to 5000@287ftlbs. You can leave it in 4th and run to 7500@250ftlbs. Going to a 4.11 rear would bring that non-ideal overdrive into play in more zones. Quote Link to comment Share on other sites More sharing options...
Rosco Posted November 23, 2014 Author Share Posted November 23, 2014 I would never run that engine below 4,500 rpm on the track. Redline would be 7,500 with the shift light coming on at 7,300 rpm. A rough starting point on trans gearing would give you a 2,000 rpm drop from first to second, 1,750 second to third, and 1,500 rpm or less for every subsequent shift. The engine has a broad enough torque band to handle that. You should be able to keep the rpms up with your current gearing. In the video you are short shifting for some reason. Starting with the rear end gear is a good idea. One reason I'm shifting early in that video is the tach quit working. But even when it did work I shifted around 6,500 most of the time. Except coming threw hog pin on to the front straight at VIR, I run it up to 7,200-7,300. I think I try and conserve the motor because I can't afford to refresh it each year. Quote Link to comment Share on other sites More sharing options...
Rosco Posted November 23, 2014 Author Share Posted November 23, 2014 Looking at the torque curve, Generally speaking you want to shift "around the peak" ie. 5400@299ftlbs. For a 1500 RPM drop that would be shifting at 6500@282ftlbs which would drop to 5000@287ftlbs. You can leave it in 4th and run to 7500@250ftlbs. Going to a 4.11 rear would bring that non-ideal overdrive into play in more zones. The genaral consesus is a 4.11 diff given my budget. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 24, 2014 Share Posted November 24, 2014 I don't know what Dave recommends for an inspection, but on my race engine I pulled the rod bearings after 25 hours and they looked perfect. I reinstalled new Nissan bearings and ran 50 hours before the next inspection, which was still good (leakdown was 2%). Sold the engine at 80 total hours and it was still at 2% leakdown. Quote Link to comment Share on other sites More sharing options...
aongch Posted December 1, 2014 Share Posted December 1, 2014 (edited) The genaral consesus is a 4.11 diff given my budget. Following your thread, nice inputs. What brand/type 4.11 will you use? I have the long nose R200 off Z31 on my RB '73 and about to put in the Quaife QDF7L. Might as well look for gearing that will keep me in my torque peak, before falling off at 5250, or keeping my foot in until past peak hp at 6100. Edited December 1, 2014 by aongch Quote Link to comment Share on other sites More sharing options...
Rosco Posted December 2, 2014 Author Share Posted December 2, 2014 Following your thread, nice inputs. What brand/type 4.11 will you use? I have the long nose R200 off Z31 on my RB '73 and about to put in the Quaife QDF7L. Might as well look for gearing that will keep me in my torque peak, before falling off at 5250, or keeping my foot in until past peak hp at 6100. I have an OS Giken LSD in my R200 diff now that I've run for a couple years. The OSG LSD is actually for a 240sx, the difference is one uses 10mm bolts the other uses 12mm bolts. The 240sx came stock with a 4.11 ring and pinion gear. My theory is... if the OSG LSD is for a 240sx than I bet the 4.11 R&P out of a 240sx will fit my R200 diff. I'll post in this thread the results. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 2, 2014 Share Posted December 2, 2014 Probably not. IIRC, the 240SX R&P is for the short nose R200. Your Datsun used the long nose R&P. There are kits available that will let you install the short nose R200 into your Datsun if you want to go that route. Quote Link to comment Share on other sites More sharing options...
VKLR Posted December 3, 2014 Share Posted December 3, 2014 (edited) It's my understanding you cant buy new gear sets for the long nose R200 So you may have to find a used unit and get the gear set out. 4.11:1 720 4X4 6/83 to 12/85 - R180 200SX Turbo 1985 to 1986 - R200 200SX Turbo 1985-1998 -R200 (Canada) 200SX Non-Turbo's 1984 to 1988 - R180 Ring gear is stamped with 37:9 Ring gear selection seems slim for the 4.11 3.90 720 4X4 1/83 to 6/83 - R180 280ZX Non-Turbo 1980-1983 - R200 200SX Turbo 1984 - R200 200SX V6 - R200 Ring gear is stamped with 39:10 More of these out there, you might have to go with 3.9? Edited December 3, 2014 by VKLR Quote Link to comment Share on other sites More sharing options...
Rosco Posted December 4, 2014 Author Share Posted December 4, 2014 (edited) I found a source for 1985 200sxt diffs, not sure how many they have but they said a few. $780 shipped http://www.qualityautoparts.com Edited December 4, 2014 by scobuggy Quote Link to comment Share on other sites More sharing options...
Rosco Posted December 4, 2014 Author Share Posted December 4, 2014 What came with the 4.38? I see duragg has one Quote Link to comment Share on other sites More sharing options...
Rosco Posted December 4, 2014 Author Share Posted December 4, 2014 BTW Taylor Racing will build you a Jerico trans for about $8k Quote Link to comment Share on other sites More sharing options...
VKLR Posted December 4, 2014 Share Posted December 4, 2014 OK so I was wrong, you can buy new gear sets.....if you are willing to spend $2,300.00 no not for a whole car, just the ring and pinion gears. http://www.zccjdm.com/catalog.php/azcarbum/dt43033/pd892771/KAMEARI_R200_Long_Nose_DIFFERENTIAL_GEAR_SETS_ Quote Link to comment Share on other sites More sharing options...
johnc Posted December 4, 2014 Share Posted December 4, 2014 The same 720 4x4 pickups mentioned above also came with a 4.38 front R180 diff in the "1 ton" version. They are less common then the 4.11 but they are out there. Quote Link to comment Share on other sites More sharing options...
Leon Posted December 5, 2014 Share Posted December 5, 2014 (edited) What came with the 4.38? I see duragg has one I have the same diff. It most likely came out of an HR31 GTS-R Nissan Skyline. Only 800 built for race homologation purposes... Edit: To clarify, the above are R200 units, not R180. Edited December 5, 2014 by Leon Quote Link to comment Share on other sites More sharing options...
logr Posted December 6, 2014 Share Posted December 6, 2014 Why not just change to a short nose R200? There are plenty of ratios available then. 3.5, 3.7, 3.9, 4.08, 4.3 to name a few. Use a Giken and the long nose stub shafts go right in. I have a 3.9 long nose that I might part with because I just put a short nose 4.08 in my 240Z and reused the Giken from the long nose in the short nose. I bought the front mount bracket that is available on Hybrid Z but will probably redo it to a mount with the same design but mounts to the other side of the diff. Quote Link to comment Share on other sites More sharing options...
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