5-Speed for North America

PostPost by: DJThom » Sat Feb 17, 2007 4:45 pm

Over the past week I've scoured the site for any and all posts relative to 5-speed conversions. The problem being that many of these options are not available in North America, or the final outcomes of the various projects are not clear.

I have surmised the following (I would appreciate corrections if I am wrong)

1) Lotus 5-speed. I have a local source for these boxes, but they are missing their bell housings so the conversion is complex. Also, I have read the bearings are no longer available, which requires a lot of machining. With an asking price of $1800, this is a high-priced and complicated and possibly unreliable option.

2) Ford Sierra. Appears to be the most common and best one, plus all the required mods and experiences are well documented. However, not available in North America and finding a LHD box from a breaking yard in a mainland Europe non-English speaking country is a bit tricky. The cost of the kits plus shipping is prohibitive.

3) Fiat 131. Discounted for safety concerns and bad first gear ratios

4) Alfa. Couldn't find whether they were all integral housing or not? Also, selector tower, spigot, need to lower the engine makes it a challenge. Couldn't find a good "list of mods" like what has been posted for the Sierra, although I know it has been done from several passing references.

5) BMW. this was suggested, but couldn't find whether it has been done successfully. Which donor car/part number? Pros/Cons? List of mods required? Info greatly appreciated!

6) Isuzu MSG/MVA. Lots of talk on this topic including what cars it was in, but confusion relative to models in Australia and Europe and Front-drive models. Specifically, what RWD cars sold in North America had this transmission? I-Mark and Impulse? Also, couldn't find any posts from people who had successfully done the conversion and documented the work required.

I appreciate any help on this subject!

Darren
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PostPost by: John Larkin » Sat Feb 17, 2007 5:30 pm

I have a Sierra 5 speed box in my Elan since mid-2004. I bought the entire kit from:

Alan Voigts,
4 Toronto Street,
Wallasey, CH44 6PR,
England.
+44 151 630 3575

He does not have email as far as I know. I am pleased with the conversion. I don't think that Sierra LHD and RHD gearboxes are different; the bellhousings might be handed in Sierras, but that may not be the case in Elans. Phone him and enquire --- he is a mine of information.

John Larkin.
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PostPost by: garyeanderson » Sat Feb 17, 2007 5:51 pm

The Ford Sierra gearbox (Type 9) is found in the Merkur XR4TI. Having said that The Murker has the better ratios 3.36 first gear as apposed to the 3.65 of the Sierra. The Merkur first motion is a bit longer and need to be shortened, on the order of 1.2 inches. There are two differrent length bellhousings, the shorter bellhousing came in the U.S. Pintos with the 2 liter engine and is the same length as the stock Elan bell. The 2 liter had the German made transmission, the starter will be different (3 bolt with a different pitch circle for the 135 tooth ring gear) The gearlever will come out in the wrong location for either Elan or Plus2 and this is where it gets complicated. Other than that its a easy swap, yea right! I gess if it were easy Alan Voigts wouldn't be asking 1500 GBP for his.

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PostPost by: DJThom » Sat Feb 17, 2007 6:31 pm

Based on the posts online, the Sierra bellhousings are handed, but I'd probably adapt to the Elan housing anyway. Issues include modifying chassis and converting from cable back to hydraulic clutch. Lots of experience on the forum, so these can be overcome. Big issue is that without one of those super expensive kits (I've read everything on the Voight kit) the gear shift is too far back.

I've found a box in the UK for 90 pounds and could have it shipped over and slowly pick away at the project. This is what I may do in the end if there are no leads on the Alfa/BMW/Isuzu options. I have no doubt that I'd sort it all out eventually by drawing on all the expertise on the forum.

There is a post somewhere on the forum that frowns on the XR4Ti box saying it isn't as robust as the European T9 versions.
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PostPost by: lotuselan2 » Sat Feb 17, 2007 8:07 pm

Darren
I have not done an Isuzu or other 5-speed conversion but I am interested. I believe the Isuzu model is some early rear-drive coupes (Impusle?), but also the pickups. There was a post about this 2-3 years ago. The good part about this conversion would be the cheap source of the box once found in a wrecker yard.
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PostPost by: garyeanderson » Sat Feb 17, 2007 8:55 pm

I am not sure but I think the Impulse is the T5 Borg Warner. There is a 2 wheel drive GM S10/S15 that has the gear lever come out just behind the main case like the Elan but the 1st gear is 4.06 (or something as bad) so you would need a Mustang gear set or complete gearbox with preferably the 2.95 1st gear and then mix and match tail shafts and shifter. Maybe a Mustang 2.3 bell modified to fit the the Ford Kent/Lotus block, the two top bolts in the bell are higher. Sure sounds like a lot of work to get a reasonable RPM on the highway doesn't it? There seems to be a recurring topic that doesn't get solved for reasonable money with the available 5 speeds. Maybe a custom made ring/crown wheel and pinion in the range of 3.08 or 3.36 would be the way to go. Kam diffs in England will do small batches of 20, the cost would be near a $1000 but it would be a bolt in and would look stock. 20 grand to get this kind of project off the ground is a lot of money to shell out of anyones pocket so maybe Alan Voigts gearbox is a bargain.

http://www.kamdiffs.com/pricing/MS%20pr ... t_2005.htm
Attachments
s10gearbox.jpg and
Found this photo its out of a 91. 91 and earlier gearboxs from the 2 wheel drive are what to look for. Some have electronic speedo's so avoid them, I am not sure what year the speedo changed. I think you will find this is the same as the Isuzu Impulse
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PostPost by: 264889socal » Sat Feb 17, 2007 10:59 pm

Just left a friends shop where the subject was custom made differential gears. He tells me he has a source for making custom gear sets, which would run about 800 to 1000USD. Minimum order of 10. Any single ratio. He is currently remaking an input shaft for my Elite dog box. They shipped the transmission from the UK with the shaft 1" to short.

Actually it was quite a nice day for an outing in the Elan. Low 80's, sunny and crystal clear. Met an interesting mix or cars on the way, a Jag 120, Acura NSX, Mercedes 190SL and a couple of early Corvettes. Do I live in a great part of the world or what?

Rob
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PostPost by: DJThom » Sat Feb 17, 2007 11:52 pm

The previous post on the Isuzu gearbox is found at:

http://www.lotuselan.net/forums/viewtopic.php?t=4079

I found this a very interesting read because in the "to do" list there was no mention of all the headaches typically associated with the T9 conversion. Also, appears speedo cable still works, which is a huge plus.

I have the Semi-close ratio box:
2.97, 2.01, 1.39, 1

The box he used was
3.22, 1.98, 1.35, 1, 0.86 - this looks pretty good.

There has been a lot of posts on the forum regarding the same Isuzu box that was used in the Chevy Chevette, but with different ratios. However, it appears the gears (as follows) are not as favourable as above.
3.79, 2.18, 1.42, 1, .86.

Also in the forum there was the following link:

http://www.drivetrain.com/isuzuMSG_MUA5sp.html

If you root around this site (rather hard to navigate) you'll find this link:

http://www.drivetrain.com/transmanuallisting.html

Here you will see it was the MSG-5K that was used in the Impulse, Pickup truck and i-Mark. I've requested gear ratios on this box, and will post the response when I get it.

Thanks to everyone for the comments so far. Yes, this topic does arise fairly frequently over the past few years, but I hope we in North America can converge on the best solution given our constraints. I would love the Voight conversion, but can't afford it. Plus, it would be too simple... :D
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PostPost by: Greg Foster » Sun Feb 18, 2007 4:40 am

Talk with John Esposito at Quantum Mechanics. He has a Merkur conversion for the elan. 203- 459-9612 He's in Monroe, Connecticut
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PostPost by: garyeanderson » Sun Feb 18, 2007 12:11 pm

Well Darren seems to be all set with the Isuzu, Is any one interested in having a custom Ring and Pinion set made up? Or should we start a new topic ? I'll ask around and see if I can get some commitments locally. along with getting orders I guess "we" would need to decide on a ratio that every one would be willing to use/pay for. If we use the stock S2 3.9 R&P as a starting point, a .80 overdrive equivilent would work out to a 3.12. A .85 o.d. comes out at 3.32. A 3.32 is pretty close to a 3.54 so I am not sure I would want to spend $800 to a $1000 when you can get 3.54 for a couple hunderd. I already have the 3.54 and I would like to drop the rpm by 10% at highway speeds so that would be in the 3.18 range or a 11 tooth pinion and a 35 tooth ring gear. Comments?

Gary
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PostPost by: mac5777 » Sun Feb 18, 2007 6:35 pm

Gary, I was going to ask the same thing. Even at $1,000 it would be a lot cheaper than all of the costs and adjustments that would be required for a 5 speed. Count me in, but first what will be the effect on my system? I have a new 3.55 with a semi close 4 speed now, so what will I endup with in first gear? And at 65 mph what revs with 145x80x13 with a 22.2 dia.
And thinking about 165x13 with a 23.4 dia. if they fit.
If 1st gear was not too high it makes a lot of sense to me. My 4 speed feels good and is strong so I'm happy with it.
Again it seems easier to change the ring and pinion then pulling the engine out again.
I think that this topic ties into the 5 speed quite well as a option.

Thanks for you motivation, Sarto
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PostPost by: garyeanderson » Sun Feb 18, 2007 9:17 pm

Hi Sarto

The Lotus Elan workshop manual lists speeds per 1000 rpm as follows

axle ratio tire mph/1000rpm
3.90 5.20 x 13 16.5 3636 rpm at 60
3.77 145 x 13 17.41 3446 rpm at 60
3.55 145 x 13 18.10 3314 rpm at 60
3.77 155 x 13 17.62 3405 rpm at 60
3.55 155 x 13 18.50 3243 rpm at 60
proposed
3.12 145 x 13 20.6 2912 rpm at 60

For all intents and purposes, the 5.20 x 13 is close enough to the 145 x 13 so you can use these calculations to extrapolate the gear ratio that I am proposing. A .80 overdrive 5th speed gear ratio on the 3.9 is the rear axle equivalent of a 4 th gear (1:1) of 3.12 axle ratio and would give 20.6 mph/ 1k rpm with a 145 x13 tire. Thats over 700 rpm drop at 60 mph, will the run of the mill twin cam engine pull 60 at 2900 rmp? I can't say but who drives at 60 any more, 3rd gear would doing 4050rpm at 60 with a semi close gearbox and that would not be any fun with the same 3.12 axle ratio. 75 mph would be reving at 3640 with the same 3.12 in 4th gear, more or less the same as doing 60 with the 3.9 ratio. At the other end, 1st gear would be good for higher speeds so creeping along in stop and go traffic at 5 mph you would probably be slipping the clutch. So there are some trade offs to be made for certain. I am just using the .80 overdrive ratio for grins, I don't know what the final ratio would be, I think it would be closer to 3.2 to 3.3 for drivability in slow traffic and starting on hills.

If there was enough interest in this, we could do a batch of 3 or 4 Ring and pinion in cases with new bearings and differential setup as a swap out basis, I have several 3.9 around that could be used to get things moving. this would certainly be more money as bearings, seal, gaskets and setup cost money.

Messing around with larger diameter tires isn't going to get the job done, you just can't fit a tall enough tire in the Elan to make it work. the 145 to 165 tire amounts to a 5 % overdrive. With a rear axle ratio swap, down time is probably a day, with a 5 speed conversion who knows. Some of the people that have done Alan Voigts swap could chime in here with there experiances. If your rolling your own, it may not get done. I have a Merkur box in the shed, I hope it stays there.

More comments are welcome from all intested in this option.

Gary
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PostPost by: DJThom » Sun Feb 18, 2007 9:54 pm

Don't count me out on a new rear end yet! I've also considered the option of a new ring and pinion, and if a group can get together to order the optimal one, then that may prove to be the best option. So, let's continue this conversation as well, either here or in a new thread.

I guess in the back of my head I want to determine the optimal "New World 5-speed conversion" so I can have my cake and eat it to.

Then perform a cost/benefit analysis versus chaning the final drive.
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PostPost by: RotoFlexible » Sun Feb 18, 2007 10:22 pm

For me, the "optimal New World 5-speed conversion" is for my CR box to magically grow a .8:1 5th speed - that would be the best of everything. Failing that, installing the lowest practical diff ratio (3.55:1?) is the easiest/least expensive option but it doesn't buy that big an RPM drop on the highway - may not be worth the effort? My 1700cc engine should have plenty of torque for relaxed highway driving, if I can get the gearing right. Everything is out of the car; now would be a great time to address this.
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PostPost by: mac5777 » Sun Feb 18, 2007 11:55 pm

Gary, thanks for all of the info, that helps a guy without the tools to do a major job himself. Rich Kamp rebuilt and installed a new 3.55 ring and pinion into my diff. and it fit right in.
I had an original 3.77 and the new 3.55 has lowered the revs to about 3500 at 60 mph. Are you saying a new ring and pinion of 3.12:1 or the 3.3:1 is what we have to decide on as options? I assumed they can manufacture any ratio needed. I am guessing that the 3.12:1 may be great at 60 but not in first gear. But something like a 3.34:1 may be the best with lower revs and 1st gear on hills and in traffic. I am not familiar how the gears are manufactured and if they will fit into all of the stantard diff. boxes. I wonder how many different rear ends lotus may have used and how many of them a new ring/pinion would fit without any futher changes.
Does it have to be an exchange of the whole diff. or just the R/P or can they just supply a new ring/pinion that I can have Rich install?
It seems like there are going to be numerous buyers for a ring/pinion that would be lower than a 3.55. If you can get a price, with quality work, what numbers will get us the best price.
I may have a need for more than just one for myself. Let's talk.

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