RedbeardRacing Posted July 11, 2022 Share Posted July 11, 2022 Good morning all. I have finally got most of the kinks worked out on my birkin s3 and have done a couple autox events. My current setup is a zetec with a t-9 that has a tall first and close ratios after that. I hit 59/60 at 8k rpm in first and close to 80 in second. For autox I'd like to be in the 48/50 range for first and 66/68 range in second. My current rear gear is a 3.90/1. I do occasionally street drive the car and in 5th @ 80 I'm turning 4k rpm so going with a higher ratio gear isn't ideal but that all depends on how hard it is to find gears and parts to change on the t-9. any info or suggestions are greatly appreciated. The previous owner sent the trans somewhere in New England to be built years ago, but he doesn't remember where. I am currently in Texas. Cheers John Link to comment Share on other sites More sharing options...
S1Steve Posted July 11, 2022 Share Posted July 11, 2022 Hi John, You have Taylor Race Engineering in Texas. If their still in business, they are gearbox specialists… Link to comment Share on other sites More sharing options...
RedbeardRacing Posted July 11, 2022 Author Share Posted July 11, 2022 Thanks a bunch I will check them out! Link to comment Share on other sites More sharing options...
7Westfield Posted July 11, 2022 Share Posted July 11, 2022 (edited) Taylor has been closed for several years Scott Young (former employee) took over the Hewland part of it, don't know if he works on anything else sy-gearboxes.com ---I think Edited July 11, 2022 by 7Westfield Link to comment Share on other sites More sharing options...
MV8 Posted July 11, 2022 Share Posted July 11, 2022 What rear tire size? Link to comment Share on other sites More sharing options...
RedbeardRacing Posted July 11, 2022 Author Share Posted July 11, 2022 225/45/15 I believe. Link to comment Share on other sites More sharing options...
MV8 Posted July 11, 2022 Share Posted July 11, 2022 That would be a very unusual 1st ratio of 2.37 with a 3.9:1 diff and a 22.97 tire od at 8k. There is a close gear set available with a 2.97 1st (51 mph) and the domestic production Merkur T9 has a 3.36 (41.7 mph). Link to comment Share on other sites More sharing options...
JohnCh Posted July 11, 2022 Share Posted July 11, 2022 BGH has a few different ratios available that can be viewed here. First gear options are 2.98 (what I have in my BGH box), 2.83, 2.75, or 2.66. I've never heard of a 2.37 in a Type-9 before, but my math matches MV8's. Are you sure the diff ratio is 3.90? -John Link to comment Share on other sites More sharing options...
RedbeardRacing Posted July 11, 2022 Author Share Posted July 11, 2022 I attached what info was given to me by previous seller. It has a full belly pan so I can't spin the wheel and count drive shaft rotation. I'll see what I can do. Link to comment Share on other sites More sharing options...
RedbeardRacing Posted July 11, 2022 Author Share Posted July 11, 2022 I believe all this work was done when Gary slutz owned the car. And I've called and spoke with him, he doesn't remember much. Link to comment Share on other sites More sharing options...
JohnCh Posted July 11, 2022 Share Posted July 11, 2022 That helps! I just looked up the Quaife gearset and they have some pretty extreme options as shown here. -John Link to comment Share on other sites More sharing options...
MV8 Posted July 11, 2022 Share Posted July 11, 2022 I just stumbled across these chaps: https://www.3jdriveline.com/webshop/gear-kits-and-boxes/ford-type-9-5-speed/gear-kit/ford-type-9-straight-cut-close-ratio-gear-kit/ Looks like you may have 2.39 1st. I'd find a used merkur box and try it out, then go through it if you're happy with the ratios. Link to comment Share on other sites More sharing options...
RedbeardRacing Posted July 11, 2022 Author Share Posted July 11, 2022 That 2.98 first looks to be the ticket! @JohnCh what's your speed at the top of second with that combo? Do you have similar rear gear and tire size? @MV8 really appreciate the help. 1 Link to comment Share on other sites More sharing options...
JohnCh Posted July 11, 2022 Share Posted July 11, 2022 I have the BGH E2 HD gearbox with a 3.62 rear end and 205/60-13 tires. Using the same 8000rpm limit as you do with your engine, my speed in gears are as follows (and no, it won't hit 8000 rpm in 4th or 5th ) Your 225/45/15 tires are only 1.3% bigger in circumference than my tires, so inconsequential. Happy to plug any information you have into my calculator so you can compare. -John Link to comment Share on other sites More sharing options...
RedbeardRacing Posted July 11, 2022 Author Share Posted July 11, 2022 So what would that be with the 3.90 rear. And do you have a good source for rear end gears. I'm assuming you have the same hi lux rear end, with a quaife diff. Link to comment Share on other sites More sharing options...
JohnCh Posted July 11, 2022 Share Posted July 11, 2022 This is 3.90. I believe Birkin uses a Subaru rear diff vs. the Sierra diff installed on Westfields and older Caterhams (they moved to BMW diffs when the Sierra supply started to dry up). I have no idea what options are available for the Subaru unit. -John Link to comment Share on other sites More sharing options...
RedbeardRacing Posted July 11, 2022 Author Share Posted July 11, 2022 Thanks again for the help. I'll be reaching out to those vendors and making a plan! I was 15th out of 180 cars on raw time this past Sunday at autox, so I'm real excited to see what I can do whenever it's setup right. I had no power coming out of lower speed corners in second, and you don't have much time to be shifting up and down around an autox course. 1 Link to comment Share on other sites More sharing options...
panamericano Posted July 11, 2022 Share Posted July 11, 2022 A lot depends on the club you run with. If the course designer aims for street cars to be under 60 mph it is quite a bit different to a course where you might get a little over 70. Either way, a shift to 3rd is usually a waste of time, but how long do you want to bang the rev limiter in second. On the other hand, if it is a fast course, like we run at Eagles Canyon, I spend 1/2 the run in third. Something to consider. Have fun. 1 Link to comment Share on other sites More sharing options...
CarlB Posted July 11, 2022 Share Posted July 11, 2022 The transmission shop he probably used was Quantomechanics. The owner is John Esposito and the number is 203-463-8299. 1 Link to comment Share on other sites More sharing options...
bball7754 Posted July 12, 2022 Share Posted July 12, 2022 I just had my Rocket box refreshed by Scott Young, and give him a AAA rating. Website is: https://www.sy-gearboxes.com/ Steve Link to comment Share on other sites More sharing options...
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