What would you suggest for a trans in a 280z L28 track car with high HP?

[Rosco]

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…  

 

[Rosco]

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!   

 

[Tony D]

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...

[johnc]

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.

[Rosco]

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

[bjhines]

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.

[Rosco]

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.

[Rosco]

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.

[johnc]

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.

[aongch]

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

[Rosco]

 

 

 

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.  

[johnc]

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.

[VKLR]

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

[Rosco]

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

[Rosco]

What came with the 4.38? I see duragg has one 

[Rosco]

 

BTW

Taylor Racing will build you a Jerico trans for about $8k

[VKLR]

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_

[johnc]

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.

[Leon]

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

[logr]

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.