There are many rations available for the T5...I like 2.87 1.89 1.28 1.0 0
.75 also 2.42 1.53 1.23 1.00 .75. The last time I checked with SVRA a 5
speed is OK since we have 5 speeds with stock trans. + OD.
John H. Hasty | MULLEN HOLLAND & COOPER P.A.
Attorney at Law
301 South York Street (zip: 28052)
P.O. Box 488
Gastonia, NC 28053-0488
Telephone: 704.864.6751 | Facsimile: 704.861.8394
JHasty@mhc-law.com | www.mhc-law.com
-----Original Message-----
From: Fot [mailto:fot-bounces@autox.team.net] On Behalf Of Robert M. Lang
Sent: Monday, December 22, 2014 7:54 AM
To: 19to1tr6@comcast.net
Cc: team, FOT
Subject: Re: [Fot] T5 conversion
Hi,
I'm not an expert on this, so I'm totally open to ither comments on the
matter...
My first comment would be that it's not clear that a T5 would give any benefit
other than being an inexpensive replacement. For most T5 setups, the first
gear is basically useless for road racing. Because of this, my first
suggestion would be to skip the T5 and think more seriously about a T10. I'm
suggesting this because you're more likely to find a good ratio mix in the
4-speed T10 and T10 knockoffs than with the T5 unless you want to not use
first.
Also, I know we're talking current E Prod SCCA gearboxes here. That means that
you are limited to NON overdrive replacement trannies. Most of the ratio sets
for the T5 that I've seen are 1:1, so that's working in your favor.
That said, all the "successful" Triumph racing gears setups seem to be in the
following range:
1st 2nd 3rd 4th
2.20, 1.75, 1.25, 1
The Dolly Sprint setup is:
2.19, 1.57, 1.23, 1
In the T10 world, the T10 c/r sets are in the range:
2.20, 1.66, 1.31, 1
If you want a usable first gear for road racing, you need to be closer to
2.0:1, the Kastner first was 1.88:1 - 2.20 is a bit too much gear to be really
usable in anything but the tightest corners...
So, if you found a Muncie "Rock Crusher" aka M22 (I think), you'd be pretty
close to ideal gears, although 2nd is a tad too low compared to that 1.57
dolly gear. If you want, I could chart out the RPM ranges for you.
Now here's the thing: T10's are replicated in NEW gearboxes from everyone, but
Summit Racing sells Richmond Gear T10 4-speeds for about $1800. If you have
more $$$ to spend, then you cannot go wrong with a Jericho and the ratios that
Kastner spec'd back in the day: 1.88, 1.42, 1.24 and 1 which I'm pretty sure
is what Sam H runs in his boxes (plus or minus) - and he can chime in on that,
if he wishes.
The bottom line is that if you are looking for a junk-yard replacement, you
have to make some compromises in the gearing. From my research - that's pretty
much "toss first gear from the mix" if you road race.
Note that wikipedia lists a lot of info on gear ratios for the B/W T5 and T56,
you might be able to use that to zero in on a donor.
Last - there's lots of info out there, but Summit Racing lists the gear ratios
for all the different boxes they sell. They have a number of Richmond Gear T5
clones and they list the ratios - you may be able to use that info to zero in
on a particular box.
In the spirit of transparancy, I'm also looking at this conversion so I'll
def. keep you posted on whatever I find.
Regards,
rml
---------------------------------------------------------------------------
Bob Lang Triumph TR6!! | This space for rent
Former NER Solo Chair |
Voice:617-253-7438 | Cell: 339-927-4489
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