I own a 1986 Mercedes Benz 300 SDL.

I did a search on this site on performance modifications for this car; the only one I found was to run a straight pipe exhaust, which increases the boost of the turbo. How much of a horsepower increase is typically found with this modification?

What sort of aftermarket turbo kits are available that will fit this car?

Is the engine capable of reliably handling increased amounts of turbo boost without expensive things breaking and if so, how much boost? I know these engines are very reliable in their stock configuration, but I've heard conflicting reports from different mechanics on how well these engines hold up(some say 400,000 miles is typical but the bottom of the engine is stressed due to the high compression and tends to crack WITH tock configuration, others say the engine is nearly indestructable and I've also seen videos of 300+ hp configurations)


I do have aftermarket transmission components installed, that can supposedly handle 600 lb-ft of torque.

I do plan to design and implement body panels that will reduce aerodynamic drag first and foremost, and may add downforce; this is being done moreso for fuel economy than anything, but with gearing changes, significant improvements in top speed could result along with a small increase in acceleration above 60 mph.

It will also be using either a greasecar or frybrid kit, with dual tanks, so as to prevent engine damage from improperly prepared 'fuel'.

 

Presumably you want to go faster when you talked about swapping a performance turbo on your W126 300 SDL. This is a very heavy car for the 5 cylinder diesel. I had a 560 SEL and it was sluggish with 230 bhp or so, with the two "side mufflers" removed. You need to bring the engine up to at least that number before you will notice any "performance".

You also talked about bio-diesel or SVO conversion. This will reduce the power of the engine not enhance it.

 

It would be a 6 cyl in the SDL, but even with the extra cyl it's still a tuna boat.

Best performance mod for the buck you could get would be a lead soled right shoe IMO.

It was designed to be a luxury cruiser, not a sprinter.

 

You Ain't gonna get her much faster, she's old and is about 3500-4000 Pounds. Maybe, a little, but not much.

 

Your car is from the era that takes allot of work to get some power gains. The new diesels, we simply tune the ECU and voila! 50hp/75lb ft tq.... at least.

 

I would be quite pleased if I could obtain even that modest figure. I don't want a race car from it; I have a Triumph GT6 electric vehicle conversion in progress for that...

Even getting to only 170-180 horsepower would satisfy my wants for this Mercedes.

While usually true(I've seen also dyno results showing small gains from SVO/WVO on some cars, but I expect a 10% or so decrease in power on mine), the purpose of that mod isn't performance. The reasons are for saving money and reducing environmental impact.

I'd be quite pleased with 'a little'. 0-60 mph ~9 seconds would be satisfactory, but if better can be obtained without costing more than $3-4k or compromising reliability, I will definately consider it.

I wish mine were compatible with a rocketchip. A E300D will see significant gains with one, allowing perhaps 0-60 mph in 7 seconds. I wasn't able to find one near me though, and at the time, only had a bicycle as viable transportation; the SDL was close and available.



Does anyone here have experience running an older diesel with straight-pipe exhaust, and if so, what power gains can be expected? With me running WVO in this, emissions and environmental impact wouldn't be much of a worry.



Thanks for your answers. I did more searching on these forums and didn't find much; I can't help but wonder how those individuals from Finland got 300+ bhp out of these.

 

I think you are talking about the Finnish diesel cars on You Tube. Both cars are modified AMG diesels in 190 D bodies. Differences are:

1) those cars are much much lighter.
2) they have what appeared to be either AMG and/or heavily modified 5 cylinder engines.
3) they have manual gear shifts.
4) did you see the beautiful thick black smoke belching out of the exhaust pipes? Say bye bye to Earth Day.

A straight pipe would help the turbo spool up faster. I do not know about power increase. Visit this good diesel site, tdiclub.com and see.

Personally, I would go for a MY 2010 Chevy Camaro for performance. 400 bhp out of the box and still returns good fuel economy.

 

"240D 3.0T" has already done all the mods you've discussed and more an can answer all your questions.

I doubt you are going to go from ~130hp up to 170 levels without a much bigger turbo and bigger injection pump valve elements.

Would be cheaper and more rewarding in the end to dirve what you have while you save that $4k (and your SDL) and shop for a 98/99 E300 turbo'd car. They are rated at 174hp and chippable for $250 to get you over 200hp easily.

All of the above is moot if you are going to burn waste oil. I can promise you that even using commercially prepared B99 that power for my E300 is down a good 10% and that economy suffers equally as you give it more throttle to maintain accel and speed in normal driving. I would expect even less economy/performance with waste oil. There is a point at which you begin causing more harm than good.....

 

You can easliy make the power you want with an intercooler, more boost, and head/intake porting.

40 hp on ANY turbo car is a walk in the park.

 

I still think the new Camaro is a better deal for performance. 420 bhp with the 6 speed manual without cylinder deactivation. If the President and his greenies had not forced GM to kill the supercharged CTS-V engine that would have gone into the Camaro as the new Z28, the Camaro of the century. 556 bhp with a 6L90E transmission this monster will be the King of the muscle cars.

For mileage use the MB diesel.

 

I am talking so much about the detuned ZR-1 engine because I was listening to one singing for about 10 minutes. Beautiful. The sales guy offered me a 10% discount off the windshield sticker without any prompting. This CTS-V is a much better buy than the Corvette. Less power but gives you so much more for the money.

The new E63 will have 525 bhp at a much higher price, maybe double, at the price GM is blowing these babies out these days. Sad but true.

 

0hp.

None. If you want a different turbo you'll have to adapt something yourself.

Yes. The engine is capable of over 300hp reliably without internal modifications. It just takes a lot of external fabrication and money to get above 180hp.

Details, please.

Increasing downforce increases drag, reducing fuel economy.

That doesn't matter. Waste veggie junk is an improper fuel that will damage the engine no matter what "kit" you waste money on.

So, spending thousands of dollars on a "kit", increasing fuel consumption and sending your car to an early death is somehow "saving money and reducing environmental impact"?

None. A straight pipe only increases noise. The power gain is very little.

BS. The 603 needs none of that and a 40hp increase is all the injection pump is capable of supporting.

 

The injection pump has a diaphram on the top rear. Pain in the butt to get to. It may still be capped off, although most older MB's have been fiddled with. You can pull the intake manifold to access. Take cap off. There is a lock nut and straight screw on top. Make an adj. wheel that will fit this and reinstall intake man. Turning this in will increase the mixture. Turn in until engine smokes under heavy accel. probably 1/2-1 turn. This will get you a little more power. Be gentle w/ the lock nut (10 mm) it will pull the threads in the aluminum if you crank on it too hard. You might try having injectors rebuilt also. Did this to my 350 SDL and helped it some.

 

the turbo should run 15-16 psi before the waste gate kicks in. Waste gate is adjustable. these 6 cly engines are not designed to run more that that. you will blow a head gasket/engine if you go more than that.

 

Adjusting the ALDA does not increase horsepower.

That is 100% false.

From the factory they are set at 9psi boost, despite the specs calling for 12psi.
The engine is capable of more than 300hp on bone stock internals when the injection pump and air induction are modified to supply enough air and fuel.

 

The ALDA does adjust the mixture. It normally compensates for changes in air pressure. You trick it into thinking the air pressure is higher. I have done this on my 300 5cly and 6cly 350. I'm sorry but it works. It increases the mixture, when it runs richer, it smokes under acceleration.

My factory engine manual must be wrong also. It says 1 to 1.2 bars on the wastegate. When you stretch the head bolts and blow the head gasket on your 300 6 cly trying to get too much HP from it, Ive got a #14 head (straight injectors) I pulled of a wreck I'll be glad to sell you. I'm sorry I'm so stupid but my 350 is still going strong and has enough power.

 

I had a 97 E300D ( non-turbo) and was not impressed with the car. My 85 and 90 have turn signal flashers that cost $15, the 97 had a $300 computer module you have to replace to fix your flasher. Seat brackets where junk-well everything was cheap plastic crap. I ended up asking the dealer if AMG was American Motors of Germany. If you want to drive the car more than 150K stay with 1990 or older. Depends on what you want and if you work on the vehicles yourself. As far as WVO- I run on a 25% mix of WVO. I clean and set the injectors myself. The oil has to be heated to get rid of water. I filter thru a 1 mic filter then let it sit for 2-3 days for anything else to settle and add injector cleaner. I have put a water seperator and two clear plastic gas filters in parallel. I have run this way for 50,000 miles, only problem hanging injectors and gas filters plug every so often. My local injection pump guy says running WVO is OK but he has seen problems with biodiesel. Anything air can get to with WVO will create gummy residue if not flushed, thats why I pull the injectors and clean every so often. All in all probably better to stick with diesel fuel. The conversion kits are a lot of dollars if you don't drive much. Of course, as we've been told I'm stupid and don't know what I'm talking about

 

READ: It does not increase power.
Adjusting the ALDA changes the boost:fuel curve, it does not alter how much fuel is injected. You had 143hp before adjusting it and you'll have 143hp after.

That won't do anything for the fact it still has harmful contents that don't burn.

You bought a rod-bender and use WVO, it doesn't get much more so than that.

 

The "rod bender" has 250k on it, is not burning oil and runs just fine. As for the ADA or ALDA or whatever you want to call it. To quote the MB 602,603 Dieisel Engines Service Manual page 07.1.10 -010/16 to 17. I'd quote the whole thing but don't type that well "... if the aneroid boxes expand, the control rod is pulled in the direction of "stop" and the the delivery volume is reduced; if the altitude decreases, the control rod is moved into the the direction of "additional volume", resulting in an increase of the delivery volume." (More volume of fuel is a richer fuel/air mixture for those of us who are mentally challanged). What this does is move the rack in the pump further in so you get more fuel when you put your foot down, that is why if you do this the engine runs rich enough to put out smoke. I did make an error in direction though, unscrew the adjustment screw for more fuel. As for the WVO, been doing it for 50,000 miles. The only problem is sticking injectors and changed o-rings to viton, WVO detiorates standard rubber O rings and fuel lines. As far as the turbo settings for a 603 from the service manual page 09.10 100/2 "Boost pressure at full load in drive position "3" at n = 4000 RPM is 0.85-0.95 bar (approx 12.75 - 14.25 psi). Page 09.10 -200/1 "A pressure switch is installed in the charge air pipe as an overload protedtion for the mechanical parts of the engine. In the event that the boost pressure rises above 1.1 plus or minus 0.15 bar (approx 16.5 psi) gauge pressure, air is admitted to the ALDA unit through the switchover valve and the fuel quantity is limited to that of a naturally aspirated engine." (Translated, mixture leaned by ALDA). I raised the boost up to 16 psi (YES, I have a boost gauge in the car.) MB in their ultimate stupidity saw fit to limit the boost to this pressure in order to prevent MECHANICAL DAMAGE. The 5 cly is a much tougher engine.

 

Again, an intercooler and head/intake porting will get you there no problem. Of course, you can take the advice of someone who has built and tuned his own 700hp street/drag car, or you can take the advice of someone who has a Volvo with a Mercedes motor in it... Which makes less hp and gets worse gas mileage MODIFIED than my wife's stock Hyundai..


The choice is yours.

 

Impressive advice so far; like always. The more you write the easier the choice becomes.

 

Talking about your wife's Hyundai, have you seen the new Genesis coupe yet? According to a review in the Toronto Star today the base car has the detuned 4 pot engine in the Mitsubishi Evo. It has 210 bhp out of the box and built with tuners in mind.

Why did MB built a weaker 6 cylinder diesel engine after the indestructible 5 cylnder in the eighties?

 

You've got that backwards... The 86-87 6 banger was the better of the two... The 5 banger was the junk that ate up timing chains after 100K.. 6 is better in every way, gas mileage, power, reliability.

The 90-91 cars has a problem that was traced back to the foundry where the blocks were cast. Not MB's fault. The revised ones, some say, were better than any other ever made.

 

Thank you for proving my point that adjusting the ALDA does not increase horsepower!

From mechanical failure of the wastegate. Proper tuning is required to get the 300hp reliably. You will NOT blow the headgasket or damage the engine.

It will do diddly squat without an injection pump capable of pumping enough fuel.

Which has nothing whatsoever to do with Mercedes or Diesels. Stick with your Korean engines, you obviously know little to nothing about diesels.

Speaking of Korean made junk, call me when that car gets to 300,000miles and is still worth $2000. Thats right, your pile will be worth less than $1000 before it even gets past 150k miles. My Mercedes will still be running long after your Korean junk has been turned into low-quality soda cans.

It isn't weaker, its stronger and much more efficient.

Thank you for further demonstrating your ignorance of Mercedes' Diesels. Stick with your Korean engines.

That is false information. The actual cause of the problem has never been determined, everything has been speculation and guessing as you did. Mercedes never officially admitted the 603.97 has a problem.

 

LOL. Whadda maroon...