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Discussion Starter #1 (Edited)
Grettings guys, I'm new to the forum and I'd appreciate some opinions on how to improve my car's performance. I have probably the slowest R129 of all you you as it is a 1991 300 SL. Fortunately the car has been restored nicely, has just 95,000 Miles on it, and I have replaced many of the worn parts including the fuel accumulator, all four shocks, the front brakes, the spark plugs, fuel injectors, 2 cylinders (which weren't working at 100%). I had the dealership tune the car up, and check everything, and now it runs really well.

I have begun a project with a friend to try to make my car quicker off-the-line, because it's a real "dog" from 0-20. We did some 0-60 & 0-80 MPH time trials, and then installed 2 new parts but the performance has not changed! We ran the tests on the exact same stretch of road both times.

This is what we have done so far and the pictures are posted below. We removed the stock air filter and installed a Twister Electric Supercharger. The Supercharger works as an air filter and also has a "trigger mechanism" which activates a fan for more intake when the throttle is pressed down at around 70%, we set the trigger so you can hear the fan begin to spin when the pedal is pushed at 70% even when the car is off as it's getting power from the car battery.

The second item we installed was a X2 Engine performance chip, which we attached to the IAT sensor. The Chip has 7 different settings, and we did our time trials on the highest setting.

Unfortunately after installing these parts we actually measured very little or no change off-the-line. It doesn't make sense as we are sure more air is being sucked into the chamber. We are also not sure if the Chip is doing anything at all. Currently we suspect that the stock muffler is holding us back.

Well, that's what's going on, I know this forum is filled with R129 luminaries, so any help, thoughts, ideas, or solutions will be greatly appreciated. Thanks guys.
 

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Save your money! The electric supercharger does zero! It can't deliver the volume of air to do what the makers claim that it does, in fact the axial blades create drag and resistance, so that's a no go (looks cool, though). The IAT just dumps more fuel into the throttle body by making the vehicle think it's colder than it is.
Read some forums on these devices
 

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I have a 300-24, your best bet is a BMC CDA airfilter (it has a carbon fibre heat shield) so it wont be sucking in hot air like your current setup (ill try to post pics of the setup).
Next, remove your center resonator to help with expelling the gases faster.
You could either go the supercharge route or turbocharger route using STS turbos
 

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Discussion Starter #6
I have a 300-24, your best bet is a BMC CDA airfilter (it has a carbon fibre heat shield) so it wont be sucking in hot air like your current setup (ill try to post pics of the setup).
Next, remove your center resonator to help with expelling the gases faster.
You could either go the supercharge route or turbocharger route using STS turbos
Thanks Spitfire, yes I would love to see the pics, did you notice a performance enhancement w/the BMC Airfilter, & was it a direct fit? Removing the rosonator may interfere w/my car passing California's smog laws, I have to get tested, but I am at least going to modify the current stock muffler.
 

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0-20 time - are you n Drive ?

yes the 0-20 is slow, if the transmission is left in "drive" you are starting out in 2nd gear. You need to put in at least 3 or 4 to force it to start in 1st. Hole shots are not what the 300SL is about. that what the 500SL is for. 300SL will give reasonable performance while returning acceptable mileage. You already are getting 1.25 horsepower per cubic inch...its only 180 cu in. The 300SL-24 is already fairly well tuned out with not much left without forced induction.
 

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When you think about it, if supercharging an engine was as simple as putting an electric fan into the inlet, everybody would do it as standard. No, sorry it's not going to work to any extent that would be noticeable. I reckon your main enemy is WEIGHT, not lack of power.
regards
steve
 

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Hole shots are not what the 300SL is about. that what the 500SL is for.
Even though the 500 has significantly more torque than the 300 I think the 500 is still a tad slower than one would expect from a 350 lb-ft V8. R129s are very heavy cars with limited traction and the Mercedes engineers geared them accordingly.

Just remember Mercedes cars aren't designed for 0-60s....they are designed for the 60-120 pulls. :D
 

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OK.

First, chances are the unencumbered intake track flows more CFM at speed without the "supercharger" than with it. Think about it. Imagine that you were blowing into an empty cardboard paper tube, air in, air out. Now take a balled up wad of newspaper and stuff it into one end so that there's no free flow of air through the tube, make sure to secure the newspaper to the tube so it can't flow out. Now blow.

If you want a faster launch for your 228HP 4,000lb car, try one of the transmission devices that force the tranny of this era into first gear. Do a search on this site. Air filters won't do it either.

In the end you'll have to come to terms with reality and accept that you don't own a 5,000HP dragster. Unless you strap a JATO or RATO pack to the roof of your car, it's not going to be quick, ever. Instead, enjoy the car for what it is, a sporty cabriolet and take a nice drive somewhere with the top down.
 

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OK.

First, chances are the unencumbered intake track flows more CFM at speed without the "supercharger" than with it. Think about it. Imagine that you were blowing into an empty cardboard paper tube, air in, air out. Now take a balled up wad of newspaper and stuff it into one end so that there's no free flow of air through the tube, make sure to secure the newspaper to the tube so it can't flow out. Now blow.

If you want a faster launch for your 228HP 4,000lb car, try one of the transmission devices that force the tranny of this era into first gear. Do a search on this site. Air filters won't do it either.

In the end you'll have to come to terms with reality and accept that you don't own a 5,000HP dragster. Unless you strap a JATO or RATO pack to the roof of your car, it's not going to be quick, ever. Instead, enjoy the car for what it is, a sporty cabriolet and take a nice drive somewhere with the top down.
.....and a pretty lady in the passenger seat. :)
 

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Steve6.

Well said.

Chicks dig the car and you look like a rock star with the top down. It's a handsome convertible.
 

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Like I said, lay back and enjoy the ride. You can tack on all the dildoos on the planet, but your 300 will never give you the linear preformance of a race car.

On the other hand, you've got one of the best looking and most congenial cars on said planet, so why worry?

Jack
 

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I told my friend I have a donkey but I want to make it run fast as a race horse. My friend thougth I was unreasonable.

Find the hidden message in the story.
 

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I told my friend I have a donkey but I want to make it run fast as a race horse. My friend thougth I was unreasonable.

Find the hidden message in the story.
Donkeys are long - lived and faithful friends just like a 129 :), race horses are highly strung and prone to kicking you in the butt occasionally :(.
Regards
Steve
 

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Donkeys are long - lived and faithful friends just like a 129 :), race horses are highly strung and prone to kicking you in the butt occasionally :(.
Regards
Steve
All this just goes to show how philisophical one must be when sitting behind the wheel of an R129. No matter the caliber of the beast, it'll have a hard time scratching a stock Moped off the line, but then again, who cares?

Jack
 

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A belt driven Supercharger will add roughly 100HP -

Since it's the 2 valve engine - you've more low end Torque
than a 4 valve would develop of similar displacement.

6 lbs. Boost is Tops for your engine without resorting to
Water or Methanol Injection.

So your 228 HP will then rough out to 328 HP ..
just 5 short of a S54B32 BMW 3.2 M-3 333 HP USA motor.

You won't be hauling around that huge 5 Liter Lump of
swinging weight either .. suffering the Handling :thumbsup:
 

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Do a search on this forum - there's a couple of twin turbos - those sixes have PLENTY of power. I had a twin turbo Mitsubishi 3000GTVR4, it was quicker that my SL500, but not as quick as my Porsche 930 (single turbo six). Now that was a QUICK and FAST car.
 

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SCITEL

OK... late responce but try this. My smog pump was going out so I removed it and installed a shorter belt. I noticed a big bifference in the low end / take off power and love it. I don't know what this means but in cooler weather the take off speed is even better and on hot summer days it is a little sluggish. Bottom line, REMOVE or bypass the smog pump!
 

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Im a little late too but I think my 300sl has some good power. I can roast the tires at a dead stop and all it has on it is a full Lorinser exhaust. Its definitely not a race car but I still beat my cousins 2010 v6 mustang by atleast 2 car lengths in a 0-50(didn't wanna speed lol) o and ur car is faster when its colder because the intake air temp is colder. Thats why people put cold air intakes on their cars.

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