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MG MGB GT V8 Factory Originals Technical - T5 torque rating?

Hi guys,
I have confirmed that I am running a 1989 world class
T5 behind a Ford 302 and the T5 is rated at 265 ft lbs.
I know for a fact through dyno testing that I have
280 ft lbs torque available at the rear wheels.
At the flywheel adding a modest 15% works out to be
322ft lbs going into the T5!
That 280 ft lbs is available from 2800 - 4400 RPM.
Am I playing with fire here every time I stomp on it?
Thanks,
Chris
Christopher Trace

Chris, go to Killerbv6.com and click on links. If you don't see a list of links right click your mouse and click refresh. Click on "Ford T5 Model Numbers." There is a drop down there that will tell you the torque rating of trans. model numbers. The torque specs will be there. I ran what I thought should be the model number for your trans, and I found 330 lb. ft. torque. This is the model 1352-249, the same one JEG's sells. There are some other useful links there as well. Let me know if you reached the links OK.

Thanks,
Dann British Car Conversions
Dann

Sounds like he already has done the research. There are a number of good Ford T-5 links in the thread just below. Like this one:

http://www.fordmuscle.com/archives/2000/09/t5swap/index2.shtml

Chris,

Your car should be a good bit lighter than a Mustang, so unless you plan to bolt on a set of slicks & launch it @ 4 grand, I wouldn't worry about it. At least, until something broke. ;)
Carl Floyd

I've worried about the same thing since installing my T5. It is also the 265 lb rated tranny behind a 333 inch stroked Ford. Like Carl says, the light weight and lack of tire bite keeps the parts inside the box where they belong. I wouldn't worry about it. What are you running for a rear diff? Dale
Dale

The rear end is a 3.73:1, one wheel spinning, because
of this rearend first gear is pretty much useless.
I get about six feet out of it before going to second.
If I'm draging someone from the lights I start in second so I get good 60 ft before third.
Nissan has a 4.08:1 limited slip diff. that would give me a more useful first gear but from what you guys are saying maybe having two wheels hooking up might just
be the camels straw.
Thanks,
Chris
Christopher Trace

Sounds like you're just not hooking up. Accoring to my calculator, with a 2.95 fist gear and 185-70x14 tire (just guessing) your should hit 39 mph at 6000 rpm - which I know comes on quick (even 225-60X15 tires would only give you 41.5 mph). With a 4.08, it would be almost 36 mph. A 3.31 would give you almost 44 mph, and a 3.08 - 47.5 mph.

Not sure how you figure a 4.08 would give you a more useful 1st gear - I think that's going the wrong way.

Wayne
Wayne Pearson

Chris, The three digits after the 1352- on the ID tag attached to your T-5 will indicate the series and the attachment on Carls' post will then give you the torque rating for your version. As your car is about 800lbs lighter than a Mustang; has narrower tires and an open diff, I doubt you will be putting the loads on the transmission it previously put up with. If you have 14" wheels, perhaps a diff ratio in the 3.07 to 3.35 range with a posi or LSD would work OK with the .675 fifth gear. The "problem" with the T-5 is its breadth of ratio from 1st to 5th giving a stump pulling low, and a Salt Flats 5th. Ford engineers have to consider fuel economy ratings as well as boat owners with steep driveways! Unfortunately,this doesn't accomodate our needs. The Motorsport version with the 2.95 low and about a .75 fifth instead of the .63 would be great. Perhaps a bitsa gearbox? Bob.
Bob Elwin

Thanks guys for all the feed back, I'll crawl under there and see if I can find the tag just to make sure.

Wayne, I run 215/65 r15s and you just made me go back and check my numbers and what I should have said was
my diff is 3.79:1 and the Nissan diff. I was refering
to is a 3.54:1 My memory use to be good!
Personally I've never had the courge to take the revs
over 5000 rpm. I spent so much time and money on this thing that I've never wanted to risk it. Besides, the dyno test showed the torque dropping off quicky just before 5000, I run a towing cam. But all this still doesn't explain why first gear feels so lousy, I mean litetrally I can be up to 5000 rpm in first gear in seconds and I supose it is more than six feet but I still feels better to start in second.
I would appreciate if you could print out that calculation for me, it would be nice to have that for
reference.
Thanks
Chris
Christopher Trace

Chris,
I use an Excel spreadsheet that I created and melded in others' stuff. I'll email it to you, but not until Friday as I won't be in the office until then.

This evolving spreadsheet allows you to compare side-by-side 5 variations of tire sizes, gear ratios, trans gears, speedometer cable turns per mile, etc. This thing should really be on someone's website.

Wayne
Wayne Pearson

Chris,

The only thing that will fix your dissatisfaction with first gear is a higher (numerically lower) rear end. A lot of 5.0 mustangs with t5's came with 3.55, 3.23 (I think) or even 2.73 rear gears. The 2.73 may have only came with autos, not sure. Your car weighs a lot less, so it just doesn't need all that gear you're using. If I were you, I'd look for something around 3.23 or maybe 3.55 to swap in. Good luck! What kind of rear end are you running right now?

Ryan
Ryan Reis

This thread was discussed between 15/02/2005 and 17/02/2005

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