My '76 LX Project
#376
Posted 26 May 2020 - 07:28 PM
#377
Posted 27 May 2020 - 11:26 AM
Measure up the Dragway wheels you want to run and post the measurements. Should not be hard to find most Dragway wheels with roughly a 0 offset (with 7" or 8" width) for the front, and that will work fine.
I wouldn't change the 3.36 diff, or at least I would go for 3.08 rather than 2.78. I had 225/65R13's on my first Torana (with 8" wide wheels) and that was good with the 3.36 ratio.
5spd swap is obviously recommended, but you may have your reasons against that.
#378
Posted 27 May 2020 - 05:48 PM
#379
Posted 27 May 2020 - 06:09 PM
With a 205/60R13 and a 3.36:1 diff ratio, my calculator says you should be doing 3091rpm in 4th gear (1:1 ratio) at 100km/h...
Tyre Size = 205/60R13 Tyre Revolutions = 552 per km Gear Ratio = 1.00 : 1 Diff Ratio = 3.36 : 1 40 km/h = 1236 RPM 60 km/h = 1855 RPM 80 km/h = 2473 RPM 100 km/h = 3091 RPM 120 km/h = 3709 RPM 140 km/h = 4328 RPM 160 km/h = 4946 RPM 200 km/h = 6182 RPM
The same parameters with a 3.08:1 diff ratio equals 2834rpm at 100km/h...
Tyre Size = 205/60R13 Tyre Revolutions = 552 per km Gear Ratio = 1.00 : 1 Diff Ratio = 3.08 : 1 40 km/h = 1133 RPM 60 km/h = 1700 RPM 80 km/h = 2267 RPM 100 km/h = 2834 RPM 120 km/h = 3400 RPM 140 km/h = 3967 RPM 160 km/h = 4534 RPM 200 km/h = 5667 RPM
And just for comparison, with a 2.78:1 diff ratio...
Tyre Size = 205/60R13 Tyre Revolutions = 552 per km Gear Ratio = 1.00 : 1 Diff Ratio = 2.78 : 1 40 km/h = 1023 RPM 60 km/h = 1535 RPM 80 km/h = 2046 RPM 100 km/h = 2558 RPM 120 km/h = 3069 RPM 140 km/h = 3581 RPM 160 km/h = 4092 RPM 200 km/h = 5115 RPM
Edited by Bigfella237, 27 May 2020 - 06:10 PM.
#380
Posted 27 May 2020 - 06:19 PM
More useless information while I've got your figures plugged in...
#381
Posted 28 May 2020 - 07:14 AM
#382
Posted 28 May 2020 - 09:18 AM
Nah, it's a standalone program I wrote in Java when I got tired of doing the various calculations manually all the time...
That's just one of many different programs, here's another one I wrote back when I was designing a fuel delivery system...
And to answer the next question that everybody asks, no, I'm not handing out any of these programs but I'm happy to run anyone's numbers for them.
Edited by Bigfella237, 28 May 2020 - 09:26 AM.
#383
Posted 28 May 2020 - 10:35 AM
Wow Andrew. Not sure what your field of expertise is but that's some impressive stuff. You know you are going to get a heap of requests. Cheers Ron
#384
Posted 28 May 2020 - 01:39 PM
#385
Posted 31 May 2020 - 04:09 PM
Attached Files
#386
Posted 03 September 2020 - 03:28 PM
Like most things the new diff build took much longer than expected. The current pandemic has not help things, making it very slow in getting parts and materials etc, but finally got there. Whilst the car was up on stands I noticed a few issues with leaking front hub seals, so off came the front hubs for new bearings seals and re-packed grease and gave everything a lick of paint while I was at it. Finally kicked it in the guts over the weekend for the first time in several months. I was stoked with how quick it fired up. It sure did put a smile on my face! First minor test drive this morning and I was extremely happy with the diff ratio choice. I had no issues getting off the line, and I felt each gear had more legs than the previous ratio. Yet to get it up to speed, and won't do so for some time until everything beds in, but initially I am happy. I am still yet to sort out rims, so this will affect things again, and will need to revisit the speedo drive gear to get the ratio right once I decide on wheel & tyre size.
Heres my little helper in the making
Attached Files
#387
Posted 03 September 2020 - 11:29 PM
If you used Commodore type seals that will happen.
#388
Posted 29 September 2020 - 08:47 PM
Several drives now with the 2.78 diff ratio. So far I love it. The car is much happier at cruising speeds. Bit harder to get off the line but I have plenty of torque up front to help with that and I am in no great rush!
3 user(s) are reading this topic
0 members, 2 guests, 0 anonymous users
-
Facebook (1)