Another Auto rear Conversion

[SpiderJim]

Well I must say that Fiat should have used the Auto rear end on the Fi 2000 out of the factory. What a difference. I seem to have lots more power but obviously an illusion due to all the gears now being a little taller. Fifth gear cruise is now more comfortable with less RPM and noise. 4-3-2 Gears are just right for spirited driving with virtually no loss of power... in fact it seems like more? 1st gear now gets me through the intersection prior to changing gears. In fifth it seems that doubling the RPM is gives you the actual speed as tested against GPS..... so 3500 rpm is 70 MPH etc. that 3-400 less RPM just makes such a difference. I live in the northern Nevada desert with lot's of long steep hills and curvy mountain corners and love it now. I have finally gotten to put 150 miles on it after blowing out my fourth gear just after I installed the diff. In a nutshell well worth doing if you like cruising with the top down and bugs in yah teeth.

NOTE!!! Later model 2L engine would probably be the minimum unless you have a super hyped up engine putting out lots of torque.

[coise]

Where did you get your auto rear ? It might be a stupid quetion but I´m not sure of the words in English... do you mean , A limited slip differential?
Thanks

[SpiderJim]

Where did you get your auto rear ? It might be a stupid quetion but I´m not sure of the words in English... do you mean , A limited slip differential?
Thanks

No I'm describing the differential and axle from an Automatic car that uses a different ratio

[narfire]

Jim, sounds like something else to keep a lookout for. My engine now has good power and that diff and axle sounds like a good upgrade.
Chris

[coise]

I got it.
I guess it was really a dumb question...
Anyway, where did you get this auto rear axle? Was it hard to install, or was it just a bolt in type of thing? My car is near the Alpes in France and we have a lot a curvee road to have fun with my 77. By the way, I´m not from Dominique strauss Khan family just in case you´re wondering
Thanks.

[SpiderJim]

Straight replacement pull out old and install the auto diff. Alpine france is a little different from Nevada. Unless you have at least a strong 2L engine you may want to stick with what you have or you may find the car under powered.

[coise]

Thanks for the advice. I have a 10/41 ratio right now on a 1756cc high compression engine (piston, cams, 34adf, 4-2-1 exhsaut, 2"1/4 muffler, etc...). You probably right, a 10/39 ratio upgrade would be enought.
By the way if you plan a trip in Europe give me a sign... I´ve been to Nevada quit a few time myself, it´s very nice.
Have a good one.

[DUCeditor]

What is the best final ratio is a question always up for discussion among owners of Ducati motorcycles. Some prefer the rather high stock ratio, others one of several choices.

The reason for the varying opinions is most often found in the type of riding/driving that is done.

People that ride on the highway a lot prefer the lower rpm and better gas mileage provided by the original ratio which is in truth an "overdrive" in that higher top speed is available is 5th rather than 6th. Riders like myself who do most of their riding on lower-speed, two-lane, roads like lower final gearing.

I suspect that the same is true for our Spiders although the choices are fewer and the change far more difficult (and expensive) to make.

On many drives I rarely get my `77 Spider into fifth gear. Since high speeds on straight roads bore me I typically drive on narrow two-lane roads with lots of tight turns. Fortunately that is mostly what we have in The Monadnocks. Indeed that is one major reason I chose to live here!

-don

[Redline]

I quite like the ratios in my '71 Coupe. Sure, it's twisting at about 4'000 at 110 kph (70 mph), but it's happy there. It will do that all day. The speed limit here is 120 kph, traffic tends to flow at about 130 kph (80 mph) and the Fiat has no problem keeping up and feeling comfortable, although I tend to take it easy and settle in at 120. What I like is the feeling that it is alert and instantly ready to go. Maybe it's the 1608 with the twin carbs, but at 70 mph, just a little prod of the throttle and I have good power and a great sound.

My friend had a 124 Spider ten years ago, and we always got a good laugh out of the gears; shifting up from 4th to... 4th-and-a-half! Same now, but I like it.

[TronDD]

I get a chuckle out of "5th" gear, too. I think it only drops by 500 rpm. Hardly worth it.

All we really need is a better 5th gear ration. The rest are fine to me, so I wouldn't want to change the rear gears.

Tim.