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View Full Version : TR2/3/3A TR3 4:11 gears in rear Diff



karls59tr
02-25-2013, 09:31 AM
What would the affect be on 0-60 acceleration with a non OD gearbox?

JerryVV
02-25-2013, 12:48 PM
It would be faster.

TR3driver
02-25-2013, 03:07 PM
Honestly, I didn't notice much change when I switched from 4.11 back to 3.70 on my TR3. I think with a stock engine and flywheel, the difference would be even less. The main thing I noticed was less of a tendency to spin the rear tires when turning from a stop sign. Which at least for me was a Good Thing as I don't need any more "unsafe start" tickets!

When Steve Hedke was preparing Scrappy for The Great Race, he did a lot of careful measurements of acceleration times under "real world" conditions. He reported finding that Scrappy was actually faster with 3.45 gears!

My opinion, you'll get more "bang for the buck" installing a lightweight flywheel instead of 4.10 gears. And it won't increase fuel consumption or engine wear either. Or lower top speed. Joe Alexander sells a nice lightweight steel flywheel that should be safer and more rugged than going all the way to aluminum.
https://i258.photobucket.com/albums/hh260/TR3driver/Misc%20parts/th_BilletsteelTR4Aflywheel-ARE.jpg (https://s258.photobucket.com/albums/hh260/TR3driver/Misc%20parts/?action=view&current=BilletsteelTR4Aflywheel-ARE.jpg)
However, it normally isn't drilled for the early clutch, so you'll need to either get it modified (I believe Joe can have this done when you buy it) or convert to the later clutch (which is also lighter).

I'm actually in the midst of building an axle with 3.45 gears and a limited slip diff; if I can ever get all the other chores out of the way.

PS, Joe's flywheel also requires the post-50K starter. If you have an early transmission without the extra bulge, a gear drive starter will still fit. Ok, so now it's probably more money than the 4.10 gears, but I still think it's better. I've been running a Fidanza aluminum flywheel for a lot of years and I really like the difference. 4.10 without OD was so bad that I risked not making TRfest 2009 (my goal in building the TR3) in order to take it back apart and install OD.

karls59tr
02-25-2013, 08:06 PM
I like the idea of a lightweight steel flywheel. I have a 60 TR3A with a TR6 gearbox.Can I use the stock clutch and would there be starter issues? I have to pull the trans anyway as I have a broken crosshaft and now you've got me thinking. :-). How do I get in touch with Joe Alexander?

TR3driver
02-25-2013, 09:03 PM
Hmm, I may have made a mistake. I don't see the lightweight steel flywheels on the web site. https://the-vintage-racer.com//
But email him anyway and see what the story is.
( ARE at the-vintage-racer.com ) It may be that they are sold out from the previous run, but might be planning a new run soon or something like that.
With a 60 TR3A you should already have the later starter. The flywheels I got were not drilled for the TR2-4 clutch, so it won't fit unless perhaps Joe can have the flywheel drilled for you (or you have a local machine shop do the work).

Geo Hahn
02-25-2013, 09:08 PM
Delete

TR3driver
02-27-2013, 03:36 PM
FWIW, I heard back from Joe A. He did sell out of the lightweight steel flywheels; but will do another run when he gets 10 orders for them. Price is $399 each plus shipping.

He also has plans to offer the same product for the TR6, if there is enough interest.