"Sweet spot" challenge. Best of multiple worlds? - PeachParts Mercedes-Benz Forum

CoyoteStarfish · #1 07-24-2008, 08:43 PM

Alright, I've got it in my mind to come up with and implement the best mix of Mercedes-Benz diesel and automotive technology to come up with a reliable, (relatively) high output, economical (within reason) Mercedes-Benz capable of running 100% homebrew biodiesel (fully mechanical engine) all housed in a classic 123 chassis without spending arm+leg to get it done.

Goal:
250-400HP, mechanically injected (Myna mod is obvious here)
~2,000 - 2,500RPM @ 75MPH - dependent on the power band of the engine
30MPG +/- 5MPG
5 or greater speed transmission

Got some ideas, but I need some help.

I'm thinking:

- 606 w/ 603 Myna'd injection pump. Or a 603 w/ 606 head (I think I read that is possible)
- VNT turbocharger w/Front Mount Inter Cooler
- Five speed a must- manual or auto, what models mate to the 60x engines? Manual preferred!
- Rear end ratio in the 2.50's or lower? - Fabrication is fine so long as it will "kinda" "sorta" fit, maybe needing new diff mounts

Drop any suggestions all you want, input is good. If you know of a part/application please share. If you have the part number it would be even better. Stats would also be nice. Ratios, specs, etc.

#2 07-24-2008, 09:23 PM

Quote:

Originally Posted by CoyoteStarfish

250-400HP, mechanically injected (Myna mod is obvious here)

That takes the "without spending arm+leg to get it done" part out of the question. That alone you are looking to spend at least $2800.

TMAllison · #3 07-24-2008, 09:28 PM

97-99 606's already come with a 5spd gearbox. Manual's ought to be avail in Europe.

The 606's 10% mpg (read hp) loss buring Bio means you are already in a hole.

Skippy · #4 07-24-2008, 10:08 PM

Quote:

Originally Posted by ForcedInduction

That takes the "without spending arm+leg to get it done" part out of the question. That alone you are looking to spend at least $2800.

That depends on you definition of "arm+leg". Have you seen what some people are paying for new cars these days?

I have seen pics of a 606 in a W123, so I know that part can be done. A 2.88 diff and overdrive should get you about the cruise rpm you want.

Your goals sound reasonable, and while more expensive than what most of us are used to spending on our cars, you will probably end up going faster for cheaper than the Powerstroke, Cummins, and Duramax guys.

Cervan · #5 07-24-2008, 11:53 PM

spend some time lightening the body of the car as well that will help tremendiously.

#6 07-25-2008, 12:08 AM

Mauri (I'm fairly sure its him, I'll check on that later) in Finland is selling a pre-built Superturbo 400hp+ OM606 for around $12,000 +shipping.

CoyoteStarfish · #7 07-25-2008, 03:04 AM

Thanks for the feedback.

My definition of an arm and a leg is approx. what a W210 E300 (turbo model) can be purchased for every other day of the week: $10k

The ~2-3,000 on the Myna is a given , and well worth it.

That figure, however, includes a full restoration + upgrades. Body work, paint, AMG rims, W211 or 10 interior components (seats, partial dash, steering wheel w/full functionality), dynamat inside and out. Classic look, new car feel.

There is absolutely no reason this car needs to weigh as much as it does, so weight reduction is on the list.

IMO a Mercedes-Benz produced 20+ years ago has just as much class and aesthetic appeal - if not more - as one that rolls off the assembly line today. All that has changed is driveability comfort and economy.

If I can build up a turbodiesel sedan with all the amenities of a vehicle produced in the last 10 years for the price of a 97-99 E300 and still have more power, rebuilt (read "new" - 0 miles) engine, along with fresh paint and interior?

Why not? Sure beats $10-12k for a E300 that already has 150-200k on the clock, on the low end of $10K are the non-turbo models. Top that with the fact that a mint/restored condition W123 300D can sell for as much as a E300? Again, why not?

vstech · #8 07-25-2008, 08:46 AM

what can be done to lighten the 123? it's unibody already, so it's pretty light in the body. I suppose holes could be drilled. the front seats are heavy due to all the springs, they could go and put in some plastic framed ones... with foam. the steel calipers have some heft to them, you could replace them with aluminum aftermarket binders... lets see... pull the springs and substitute in some coil over shocks... and we're done... what else can be removed? glass?

Cervan · #9 07-25-2008, 09:18 AM

Quote:

Originally Posted by vstech

what can be done to lighten the 123? it's unibody already, so it's pretty light in the body. I suppose holes could be drilled. the front seats are heavy due to all the springs, they could go and put in some plastic framed ones... with foam. the steel calipers have some heft to them, you could replace them with aluminum aftermarket binders... lets see... pull the springs and substitute in some coil over shocks... and we're done... what else can be removed? glass?

all interior can be tubbed and then replaced with racing seats. thats atleast 100 pounds right there, cut out everything that isnt needed for structeral integrity probibally 50 pounds. chaning all four wheel rims and tires with performance tires/rims that weigh less and have better traction/grip. will net you better acceration because of the lower mass and wider tire. take off bumpers (easy 60 pounds right there each.) take off all trim, take out spare tire and take out fuel tank metal sheet's, remove sunroof and replace with plexiglass, remove all windows (except for windshield,) replace with plexiglass (those things are very very heavy) Weld rear doors shut to strengthen body, and remove everything from the inside pannels (cut them out.) Stitch weld body to strengthen it. thats preetty much all you can do.

Thats about 4-450 pounds that you can remove. lowering the vehicles weight down to about 3800 pounds with the driver, thats a huge upgrade considering that every 100 pounds you take out, you give your vehicle about 10 hp.

vstech · #10 07-25-2008, 09:32 AM

ahh, well, yes I am sure all that would lighten the car, but I think that's a bit beyond "the sweet spot" in terms of keeping the car useful.

Jetmugg · #11 07-25-2008, 09:42 AM

My 2 cents - forget about the W123 body shell. The aerodynamics stink.

Stay with the W124 body, set it up for manual climate control, manual seats, manual windows, manual transmission. The 603 engine can achieve the 250 min HP you are looking for. Build it. Drive it and enjoy it.

SteveM.

CoyoteStarfish · #12 07-25-2008, 09:45 AM

Whoa whoa. Let's not get too crazy here.

Lighter AMG rims, drilled/slotted rotors, coilovers, and W210/211 seats front and back are what I had in mind. Or I may just have my seats redone in memory foam. Carbon fiber hood/trunk lid (painted of course, no rice please!) and maybe if I get crazy(er), front fenders and door skins.

My first thought is that if I rip out all of the old 1983 insulation in the vehicle I'll drop the weight a good 30-50 pounds. Any steel I can replace with aluminum I probably will.

If I can find the fiberglass body kit used on a AMG W123s to delete the bumpers I'll jump on that as well.

Another thought I had was, would the weight of a skid pan make up for itself in aerodynamics?

Cervan · #13 07-25-2008, 09:49 AM

Quote:

Originally Posted by CoyoteStarfish

Whoa whoa. Let's not get too crazy here.

Lighter AMG rims, drilled/slotted rotors, coilovers, and W210/211 seats front and back are what I had in mind. Or I may just have my seats redone in memory foam. Carbon fiber hood/trunk lid (painted of course, no rice please!) and maybe if I get crazy(er), front fenders and door skins.

My first thought is that if I rip out all of the old 1983 insulation in the vehicle I'll drop the weight a good 30-50 pounds. Any steel I can replace with aluminum I probably will.

If I can find the fiberglass body kit used on a AMG W123s to delete the bumpers I'll jump on that as well.

Another thought I had was, would the weight of a skid pan make up for itself in aerodynamics?

having an underbody set of pans welded will help tremendiously with aerodynamics and interior sound reduction. ( i mean the mercedes underbody is no airplane under there...) Do not forget the stitch welding, it really really helps its so cheap too, if you have a mig or arc welder you can do it by yourself too. Just go slowly along all of the seams in the car, it will add about 10-30 pounds to the weight of the vehicle but it will stiffen it up substancially.

vstech · #14 07-25-2008, 10:00 AM

a skid pad... I always wanted to put an entire plate under a car. completely remove any underbody air drag. total front to back... I can get 5x10 sheets of aluminum... (gosh they must be pricey nowadays...) I was thinking of setting one under a car and seeing how much of the stationary underbody I could cover.

Cervan · #15 07-25-2008, 10:01 AM

Quote:

Originally Posted by vstech

a skid pad... I always wanted to put an entire plate under a car. completely remove any underbody air drag. total front to back... I can get 5x10 sheets of aluminum... (gosh they must be pricey nowadays...) I was thinking of setting one under a car and seeing how much of the stationary underbody I could cover.

You could probibally get one huge sheet to go from the tranny bellhousing all the way back to the RLCA's and the bumper.