5 Speed Transmission

Does anyone have advise or information on a 5 speed transmission option.

IM and I would guess others offer a 5 speed speed, or 901 -5 speed transmission option on the Roadster or Speedster.

Does anyone have experience driving a IM with a 4 speed and a 5 speed? My car has the 2160cc engine, strong torque, and runs well with the 4 speed and 3:44 rear end, but it just seems to be missing a gear...like shifting to third may give it good legs (low rpms) but loses a bit of the zip or wind up in rpms....

I am wondering the cost versus benefit..anyone know about what it costs to have this option added to an IM in lieu of a 4 speed?

Henry.

A 5 speed transmission is expensive...the alternative is to have a 4 speed trans built for your needs

I've never been a fan of the old Porsche 901 5 speed. I had one in my 911 powered VW single cab and I hated the 'dog leg' first gear. In my opinion, the 915 is a better tranny. Of course, the G50 would be the best choice, but it's so darn long. Gene Berg makes (not sure if they still do) a 5 speed conversion for the beetle tranny, but fabrication must happened, and this kit is not cheap either.

Berg 5speed. About $3200

Robert,

An excellent question when you look at the power to weight ratio of early 911 its clear that the 901 is an excellent choice for the Speedster Replica. The 901 was used in early 911s with hp ranging from 110 to 180. These cars weighed a few hundred pounds MORE than a typical Speedster Replica. 1972 saw the introduction of the 915 trans and the 2.4 911S engine producing 190hp that was the reason for the stronger 915 trans to handle the higher output from the 1972 2.4 911S engine. If you look at a VW engine producing 150 hp in a Replica that weighs a few hundred pounds less than a 911 one could expect similar performance from a 901 trans.

Interesting enough Porsche also used the 901 trans in the 914 with hp ranging from 80 to 100. You can use the Type IV engine from a 914 in a replica with the 901 from a 911 but you should change 3rd and 5th gear to better handle the torque curve of the Type IV. It is a direct replacement from the 914 trans, swap 3rd and 5th gear and you are good to go.

The problem with using the 901 in a Replica is that the mounting points for the trans are different. If it is a tube frame it

Karl, thanks for the feedback. I was trying to get as much information as I could about 5 speed options for a IM speedster/ roadster.

Are you going to be at Carlisle this year? Will your car be there with you? I would like to see it and/or maybe get a ride in your car with the 5 speed.

If you are, I look forward to meeting you and seeing your IM.

Robert,

Not only will I be at Carlisle but Henry from IM will be there as well. Henry can tell you much better than I if it

I too looked at changing the 4 speed in my IM when I switched engines last month from 2100 to 2332. On Henry's advice I stayed with the 4 speed. He has the 5 speed but really felt that it would not be valued added for my situation. Also there is some modication work that he would need to do so additional time and money there as well.

Must say with the engine switch I am much more pleased with the engine/tranny package.

Dean

lol, there's nothing like a little extra HP huh Dean!

Okay. I actually traded e-mails with Henry. I'll speak to him at Carlisle. I look forward to meeting the rest of you that are attending.

Thanks for the responses.

I have the 901 in my pan based speedster. I also have a 69 1600cc 912 engine(about 90hp). Does great in my car. Looking at the instalation, the hardest change is the shifter. The old VW base has to be cut out and the Porsche shifter base welded in. There is some cutting on the pan but the brackets to mount it in the pan are fairly strait forward.

I will post some pics when I get back from vacation.