1974 450 SLC performance

[cgoodwin]

I am looking for any information of increasing the HP of this engine.

Headers?
Swap the injection system to a Megasquirt?
Different cam grinds?

Any thoughts???

[cgoodwin]

Also looking at the installation of a LSD, it looks like the 560SEL diff might work from another old post, although the gearing would change from 3.07:1 to 2.47:1 and that might cause serious off the line power loss:

560----------2.47:1 LSD standard equipment
380----------3.27:1
450----------3.07:1
*450---------3.06:1 US 1979
*450---------2.65:1 US 1980
450SLC 5.0---2.72:1

[GaryF]

Hi,

There's a few threads about this if you do a search, I think the general opinion was to replace the heads/cams with some from a Euro engine. Higher compression and more agressive cams.
I've not seen hard evidence (dyno results) that megasquirt gives more power but can improve economy and smoothness.
With only three gears any changes to the diff ratio will leave the car compromised.

Maybe start with a different car if you want a tyre smoker ?

Good luck

[cgoodwin]

The goal is to build 4 matching 450SLC rally cars so any other car is not an option, I am not looking for tire smoking if there is none to be had, I am simply looking to get ALL the power that is available. The cars that Mercedes campaigned were said to be basically stock motors and transmissions and they performed well, if however, a simple cam change would give more grunt, I would love to know. The LSD is also a must as without it off-road performance would be greatly reduced.

[GGR]

The cars raced by Mercedes were 450 SLC 5.0. They were equipped with 5.0 alloy engines. The power of the version available to the public was 240 hp DIN and 41 kg of torque. They had alloy bonnet and trunk lids as well as alloy rear wheel arms and alloy valances in the front and rear bumpers. These are relatively rare cars but they still go for rather cheap on the net. You could find one (or four) and bring them to your expected level of restoration for cheaper than modifying 4.5 SLCs. If you already have the cars your best option is to find four 5.0 liters alloy euro engines out of grey market W126s. They develop 250 hp DIN and 39 kg of torque. They are the closest to their original engine and they would be cheaper (and lighter) than all the work needed on the 4.5 iron block to bring it to that level of power. You would then need to find some rare Tri-Y exhaust manifolds, or go with 560 SL manifolds. You can also find alloy bonnets and I believe alloy trailer arms on the 560 SLs. If you need a specific 450 SLC 5.0 rear end with alloy trail arms (but no LSD) I can put you in contact with someone who's got that in West Virginia.

[alabbasi]

And if you want a real deal 450SLC 5.0 with an LSD, hit me up because I have one for sale

[cgoodwin]

I am pretty sure I had read that the 5.0 was introduced several years into Mercedes short ralley career, around the time of the Acropolis Ralley.

[GaryF]

Originally Posted by cgoodwin

I am pretty sure I had read that the 5.0 was introduced several years into Mercedes short ralley career, around the time of the Acropolis Ralley.

I believe the rally version of the 450SLC which started in 1978 had the newly developed 5.0 all alloy engine from the start.
The confusion might be that they still called it a M117 engine

[GGR]

I had the 450 SLC 5.0 n°52, one of the earliest ones, and it was a '78. Initially only 500 of these cars were made for homologating purposes. More were done later given its commercial success.

[cgoodwin]

What about headers? I can't seem to locate headers.

[bwostosh]

If I had the space I would buy this Euro SLC,
I heard it run, It may go cheaper
Pictures in ZIP file
http://members.cox.net/bostosh4/450SLC/450%20SLC.zip

[ja17]

Hello,

I built a FIA spec. 450SLC Rally car. I ran it in Australia a few years back. Weight is your biggest enemy. Weight will fight you every bump and jump in the road. Weight will eventually break things. Anything you can do to reduce the weight of these over weight rally cars will help performance and durability.

My SLC turnes the quarter mile in the low 14 second range. It has a alloy hood, no AC, and lighter roll up windows. The fact that the 5.0 engine block is aluminum and lighter than the old cast iron engines is a double bonus, more power and lighter. The magnisium rear control arms are a bit ligter also. These are found in other models besides the SLCs. My euro bumpers are quite a bit lighter and better looking than the massive USA safety bumpers which add weight and length to the car.
My car is a 450 SLC and has the original 4.5 cast iron block. It is a euro car and is all euro spec; no emission devices, high compression no cats. I believe these were rated at 245 hp. In additon I installed a four speed standard transmission which is lighter than the automatic and more aggresive off the line over the three speed automatic. If you research the factory rally cars you will find that they used a very high ratio rear diff I believe it was a 3;69 to 1 !!

I am using a 3;27 to 1. These ratios give you lots of torque and accelleration. Top speed will suffer a bit.

I have run 14", 15", 16" and 17" alloy rims and up to 245/50 17" tires with no clearance issues. The 17" were used on SLK 32 AMG rims which have a slightly different off set which helps clear steering parts and inner fenders.

The resonator (center muffler) has been removed and straight pipes installed with just the rear muffler to save weight.

Progressive rate springs have been installed all around with standard bilstein shock absorbers. Polyurethane bushings on the front sway bar.

Safety equipment like a roll cage, fire extiguishers etc. will add weight back on.

Hope this helps.

[cgoodwin]

I plan on using euro bumpers and ditching all emissions gear, no cats, dropping every ounce possible but keeping the auto. Starting with the 5.0 would be nice but expensive, I can get a straight slc for $1000 - $2000 all day but a 5.0 will run me at least $6K

I can't seem to find trunk spoilers or headers anywhere! Are they available?

I plan to use the cars in vintage long distance rallys and adventure trips down the Baja and mainland Mex. So they will be competing with Volvo 122's and the like so I think the durability and power will have the same results Mercedes had in the Bandama etc.

[alabbasi]

Originally Posted by cgoodwin

I can't seem to find trunk spoilers or headers anywhere! Are they available?

I have an AMG front spoiler on my black 350SLC that I plan to make copies off at some point before I sell the car. The 350SLC has a rear rubber spoiler but it's worse for wear. Maybe a mold can be made from it.

I have good friend who is very good with fiber glass and should be able to make a mold.

I also have a brand new rear spoiler that I plan on installing on my black 500SLC as it does not have one.

[mercmad6.3]

You can buy then easily off ebay.de. I had a Zender front spoiler and AMG boot spoiler on my last SLC. The genuine parts are not fiberglass but ABS plastic which is far more durable.
I think the only difference with a Euro 450 is to do with the pistons and cams,the heads are all the same.
The really good driving SLC's (apart from the 280's) are the 350SLC with 5 speed. not only faster than the 450's but are also economical. 'Don't bother chasing around looking for alloy W107 rear trailing arms (I thought they all were any way..) just get the back end from any W116. Get the back end with the anti dive link. Same parts,even the W116 450SEl 6.9 has 107 parts and numbers on the back end. The Front end is just a common or garden W114 item,nothing special there either. You can buy complete W126 500SE/SEl's any day of the week for peanuts but if you are worried about costs now,how are you seriously going to rally a car,any car for that matter?