E46 into Jowett Jupiter 1951

[Carl Ring]

Hi folks,
I have an old sportscar, a Jowett Jupiter which has a strong tubular frame and aluminium body. Curb weight is 860 kgs. The BMW engine that goes in is M54B30 with 231 hp. The original engine had 63 hp, although the car won Le Mans three years i a row, Monte Carlo, RAC and other races. Only a year ago it won Le Mans Classic again.
So, now with the new power plant it should beat the shit out of most cars. The road holding was this cars strength with torsion suspension all around. The former engine was positioned forward of the front axle! Now the B30 will sit behind it. You will shiver and tremble when you see this coming- if you reach time to observe...
Now, head into questioning:
The Jupiter has a body width outside the wings of 1570mm. Inside and clearance the track forward/aft can be 1559 mm maximum.
The car is light and will have a track of 1490 in front and larger 1490 aft. Why is that on E46?
What do I do to get the wheels inside 1550mm? Or do I have to make a beating on this jewel to make it wider on the body?
Understand that I will take the whole drive train from E46.
With standard rim (8" and 225 tires ?) it needs 1593 front and 1653 rear if I go for 195 front and 245 rear., meaning widening 43 body front and 46 rear, an action I would not find handsome. This based on E46 original ET 41.
Now, how would a higher ET rear and 225s change the handling of this car?
Other than this-
What if I have wide rear tires on this light car? Will it run steady as a glue stick on the road?

I would enjoy to hear your expertise on this. Thankyou. By the way, I don´t know how to insert pictures, so google pictures of the racing version.

[legoman67]

What are you trying to do? The e46 is unibody frame.

The largest factor in handling of these cars is the 50/50 weight distribution. Doesn't matter how wide the rear tires are, if the back of the car weighs nothing you wont have traction.

[Carl Ring]

What are you trying to do? The e46 is unibody frame.

The largest factor in handling of these cars is the 50/50 weight distribution. Doesn't matter how wide the rear tires are, if the back of the car weighs nothing you wont have traction.

My Jupiter has a strong tubular frame and alubody.It will have 50/50 weight dsitribution, As we go, the weight will move back substantially in the acceleration phase. Wider tires in rear are there to allow for better friction as we all know. The whole drive train is E46.The car has 850 kgs curb weight and will give Ferraris headache.
The E46 has a wider track in rear due to weight distribution. This I found out. Note that I will have the entire engine behind the fore axle- That is a dream for most car builders.

[Honolulu]

Putting the much heavier BMW engine almost entirely forward of the front axle may have worked on the original which had a much lighter engine. Using a bimmer motor in that position will make is severely front-heavy and likely destroy handling without miraculous suspension engineering.

Also, I wonder if four times the power will simply twist the tubular frame to knots - destroying whatever suspension and chassis engineering was intended to compensate for the severely front-heavy machine you'll need.

The modifications to accomplish this may leave you with something that remains a Jowett in exterior appearance only, like USA "stock" cars that are tube-framed, composite-bodied cars that only superficially resemble their claimed ancestors.

[Carl Ring]

Putting the much heavier BMW engine almost entirely forward of the front axle may have worked on the original which had a much lighter engine. Using a bimmer motor in that position will make is severely front-heavy and likely destroy handling without miraculous suspension engineering.

Also, I wonder if four times the power will simply twist the tubular frame to knots - destroying whatever suspension and chassis engineering was intended to compensate for the severely front-heavy machine you'll need.

The modifications to accomplish this may leave you with something that remains a Jowett in exterior appearance only, like USA "stock" cars that are tube-framed, composite-bodied cars that only superficially resemble their claimed ancestors.

Yes, the frame is rebuilt and rigid and strong enough now. The engine with gearbox is 233 kgs and balances on the front axle. Weight ratio is 50/50. Curb weight 750 kgs.

[BidNo]

That's a beautiful car. Crazy that the highest grade fuel available when built was 72 octane