I completed a 5 speed conversion for my Plus 2 using an alpha box last year, final drive is .78 with a 3.55 rear cruises very comfortably. We made a 1" aluminum adaptor to mate the original lotus bell housing to the front of the ALpha box. Fit in the car was very easy, kept the originial shifter location, very little fitting problems. Biggest hassel was the spreedo conversion but that looks to be solved as well. Have about 500 miles with no problems. Any one wants to see the car in Massachusetts or learn more, drop me a note.
Hi Rick
Good to see someone local doing all the engineering, I would like to take a look some time. Its been a while (92 or 93) since I have been out your way. I stopped at your shop and met you an Noel Poduje. Thanks for the info
Gary
I would be very interested in knowing more about your conversion. Which donor car provided the gearbox, and what are the ratios? Were you able to use the standard Elan clutch mechanism? How did you go about sorting out the speedometer?
Darren
Rick,
Count me in for a visit as well. Gary seems to have been a more recent visitor, I don’t think I have been out your way for at least 15 years. I have not seen your +2 since the first LOG in Connecticut when you were there with your race car as well. I seem to recall your +2 is very close to mine in terms of chassis number. I have been thinking about going the way of the Alan Voights Ford T9 conversion. I am very interested in all the details, ratios of each gear etc.
Russ
Gear box was out of a Giulia, ratios: 3.304, 1.988, 1.355, 1.000, and .791. Speedo converion used the stock right angle drive with a new retaining nut (cut for meteric threads) and a ratio adaptor spliced into the speedo cable from APT(gaugeguys.com/). Also had a custom driveshaft made. All th original clutch components can be used save the disk which is a different spline but very available. For my conversion I close to convert to a annular slave cylinder(Dave Bean amoung others) while it was easy to design a mount on the adaptor plate. Had some modificatios made to the gear box rear housing for clearance and mounting but nothing major and only needed minor welding for a tranny mount.
Russ and Gary. You guys are more than welcome to come over and take a look. Car is at my home in Grafton and on stands for it winter service and tweeks. At the same time you can take a look at Danny’s Plus 2 with the 1850cc FI and spyder conversions. Weekends are best and everything is unheated so pick a warn day. Call me at 508 839 3418.
Hi Rick
I will talk with Russ and a few other interested parties to establish a good weekend date, that way you won’t have to show it off to many times.
Gary
I found this page on Alfa Giulia gearbox with photos of a strip down, not sure this is the one Rick is refering to but the shift is in the right place. the donut on the back has me worried though.
Gary
Looks the same. Donut was carved off with a hacksaw and replaced with a welded on mounting lug for the tranny mount.
If you have done a CV joint replacement the donut might be good to give you some give in the drive train. Many modern cars have rubber discs in their drive shafts.
Gary,
Please sign me up as an “interested party.” Rick told me about this conversion while we were discussing the 1700cc engine.
Thanks,
Andy
Hi Andy
Bill Gavin is interested too. sounds like Rick is in for a flock of Lotus nuts to show up and paw all over his Plus 2. I am interested in the F.I. 1850 engine in Danny’s car too.
Gary
Attached are a couple photos of the tranny before installation
photos will not attach, tranny installation was easier. Anyone wants photos email me at [email protected]
Hi Rick
Send them to me at [email protected] and I’ll get them up here.
Too cold today to do much else anyway.
Gary
I note that Burton Power offers two “ZF gearbox to Ford 4-cyl” bellhousings, one with the starter on the left, one on the right, both aluminum. (Transmission and Clutch / Bell Housings / Lotus Twin Cam 8V). Aluminum and priced accordingly. I wonder if these work with the Alfa gearbox? An adapter plate is a lot less expensive.
The quoted gear ratios for the Alfa 5-speed are the standard wide ratio gears. This gives a ratio drop of 66% between 1st and 2nd gears, rather wide (You are looking for something closer to 50%, at 66% the engine will bog noticably on the 1st-2nd shift. Shifting at 6500 brings the revs back to 3900, under the torque peak. On the street, shifting at 3000 rpm brings the revs back to 1800). And the .791 5th gear would give a potential top speed of 143 mph at 6500 rpm and with 155-13 tires and 3.77 diff (and 154 mph at 7000). You would need a very strong engine to pull such a 5th gear. It might be mere reasonable to use a 3.9 or 4.11 with such a tall 5th.
Looking at my old SCCA Production Car Specifications, Alfa homologated 3 alternative gear sets.
2.76, 1.78, 1.30, 1.00, and 0.85 is one set. This gives a 1st to 2nd ratio drop of 55%, quite useable. Shifting at 6500 rpm brings the revs back to 4200, a noticable and useful improvement. And 6500 in 5th gives 138 mph.
Another homologated set is 2.54, 1.70, 1.26, 1.0, and 0.85. The first 4 ratios are somewhat similar to our 4 speed transmisison, with an added 5th. the 1st to 2nd ratio drop is 50%. Shifting at 6500 brings the revs back to 4400. And the potential top speed at 6500 is 133. This probably is the ratio set to use if you can find it from some Alfa specialists, although the previous set would be quite satisfactory.
The last homologated set is 2.33, 1.58, 1.21, 1., and 0.88. These are similar ratios to the Quaife T9 semi-helical rally gear set. The 1st to 2nd ratio drop is 47% and the potential top speed at 6500 is 129. However, it is probably geared too high in 1st to be a good street box, giving 49 mph in 1st gear
The above information was produced using a spreadsheet that allow easy modelling of different car parameters. It is invaluable when considering some of these possible scenarios, particularly when considering different tire sizes, diff ratios, and engine speeds. Request a copy from me by sending an email to [email protected].
David
1968 36/7988
There is more info at this link on ratios and tooth count and so forth.
and click on Alfa Gearbox Ratio Chart
The ratio options are very worthwhile and helpfull. I can not say that I have experienced the bogging between gears but that is likely due to my engine being a 1710 cc that makes about 120 Ft Lbs at 3300 revs. Next time the box is out I may try an alternative gear set. Thanks