M117 to M120 Weight Impact
 

Well I finally brought my cars down to be weighed. Both cars were cleaned out and weighed without a hard top. The hard top weight is unknown at this point. Both cars are fully operational and weight of additional 10 Lb, for condenser and RD and Freon was added to the M120 560SL since it will be added later.

Both cars were weighed with ~ 1/2 tank and estimated weight of gas was subtracted.

Stock 1988 560SL. = 3472 LB
1986 560SL with M120 Engine and 722.6 Transmission installed = 3770.5

So the addition of the M120 engine and 722.6 Transmission cost 298.5Lb.

The engine and trans by themselves account for 174 Lb additional. Subframe modifications account for 17 Lb. The additional 108 LB is probably mostly due to larger wheels tires and breaks from the SL600 and rear subframe mods as well as other small unaccounted for brackets and weldments.

Unfortunately I wont know the hard top weights until the winter when I take them down. But it looks like the car is coming in at around 3850 LB.

hmm a extra 300Lb for something close to double the power and a much smoother running engine with a lot better gearbox is one great trade off. :) Plus its going to sound awesome.

Already does ;)

http://www.peachparts.com/shopforum/video-forum/242976-m120-v-12-into-560sl.html

I think John, the extra 300LB shouldnt be a hindrance given the additional BHP. The 450SLC 5.0 weights in at 4420LB. Perhaps a consideration to the front end that takes most of the additional 300LB could be a spring replacement with the blue mark springs (long) if you have the red mark (short) springs and thicker spring pad to keep the nose off the ground. Presumably a good spring setup would be spring number 1143210704 with a reduced spring travel per 1000 N load of 16.4 and wire diameter 16.3. There are 7 variances of front springs for this model. An awesome achievement.:eek:

Thank you Deltacom

4420 for the 450SLC 5.0. That is an alloy engine correct. I would assume that the 4420 is a Gross Vehicle weight, including driver, passengers, fuel and stuff. Yes/No?

I was actually surprised with the stock springs in that the car does not appear lower. It is but only slightly. The right side is actually lower than the left slightly and I may try to swap spring sides to correct that or just a new pair of the stock setup.

I woulds estimate ~200 Lb to be additional sprung weight on the front axel, 30 Lb to be additional sprung weight on the rear axle and 70 Lb to be additional unsprung weight on all wheels tires and breaks.

So tell us how does it feel driving it? i love the M120 and in such a light car i bet it really has a sting in it’s go :)

you have managed to put one of merc’s master piece engines in one of its timeless work of art

what’s more is you did it in style making it look like it was factory work.

We demand a photo thread, plz

Thanks Jay

How does it feel to drive it?

Well the fastest car I ever drove was a BMW 750. That car weighed about 500Lb more and had 89HP less. But that was also 20 years ago and I was 20 years dumber. Now 52 years old and having just got out of the hospital for heart trouble I suffered last week I will take it easy with this. I have had very few momentary full throttle burst.

As far as driving it. At this time I have not observed any weird handling characteristics but I haven't brought it to the limits of adhesion either so its too early to tell. I'm sure there will be massive playing around with bars and springs once I get my wheels straight.

Driving it is smooth as glass and really fun. I'm kind of taking it easy for the moment because I want to take it to Buffalo next month and I don't want anything to happen to it.

Pictures are posted in the attached link. I had asked Adam to lock up the thread since the build was essentially complete. If it was left open it would become a chit chat thread with no more build action. We can start other thread for chit chat like this one.:D

http://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/178997-m120-into-560sl-pictures.html

God bless u john, and wish u a healthy life man.