[huramentzefix]

I am looking at some Mercedes Benz W208 CLK R170 Eaton (M62 I believe) A1110900380 Supercharger.
My little car is sometimes overwhelmed with it's duties to tow the Humbaur HKT 3500.37 trailer.
It's a 4000kg fully loaded trailer and I can feel it when it's being dragged behind the car but it works.
The 1.7L 83HP engine does it OK and I have no intensions to go fast. This engine has an extremely long intake-duct and good driveability for it's size. but above 4500RPM is not much movement anymore, but that's OK. I barely go up that high.
But some low end torque would be highly appreciated.

If I just use the supercharger up to 2200-2500RPM can I then pump higher pressure than the usual 0.5bar without alteration of the compression ratio? All I want is lot's of torque at low revs. I rarely drive faster than 100km/h, even without the trailer.
Is it possible to start with 1.5bar from Idle if load =>80%/90%. reduce boost when revs go up towards 0.8bar and then switch the supercharger off at 2200RPM?

[PSIG]

Sounds like a reasonable set of project goals. I doubt you need that much boost. Design for the purpose and don't get greedy. Many years ago, I had a similar situation with a SJ410 Suzuki (Samurai), which was just a little under-powered by its 1.3L engine. A 1.5 or 1.6 would be perfect. Other mods like a Weber and headers didn't' quite get it. I added a small turbo for only 3 to 4 psi (.2 to .3 bar) boost. Perfect with about 20-25% more power.

There was no concern at higher rpm, as reduced throttle removed all boost. With how superchargers work, lifting the pedal for cruise would also remove boost, as they only make manifold boost if you demand more power than the engine makes without boost. I hope that makes sense.

You can switch the compressor off and breathe through the bypass (I assume the bypass on that model is vacuum operated?). Or drive the SC full-time and just open the supercharger bypass for times no boost is needed, reducing power loss driving the supercharger but simplifying the drive. This would require the bypass to be electronically controlled (perhaps using the VVT function and table) for switching bypass at any load or speed. Several ways to approach it.

As superchargers increase boost with rpm, you are using a device that works better at higher rpm, for only lower rpm. A small quick-spool turbo sized for your target range would seem a more efficient power adder, but likely worthwhile in any case. Sounds like a fun project, and have fun!

[JHolland]

You're towing a 4 tonne trailer with a 1.2 tonne Lada Niva?

[huramentzefix]

I just had the towing-fairy-tale-action-story nicely typed up, but when I posted it it asked me to sign in. So it's gone ...
The short answer is: why not!

[huramentzefix]

Sounds like a reasonable set of project goals. I doubt you need that much boost. Design for the purpose and don't get greedy. Many years ago, I had a similar situation with a SJ410 Suzuki (Samurai), which was just a little under-powered by its 1.3L engine. A 1.5 or 1.6 would be perfect. Other mods like a Weber and headers didn't' quite get it. I added a small turbo for only 3 to 4 psi (.2 to .3 bar) boost. Perfect with about 20-25% more power.

There was no concern at higher rpm, as reduced throttle removed all boost. With how superchargers work, lifting the pedal for cruise would also remove boost, as they only make manifold boost if you demand more power than the engine makes without boost. I hope that makes sense.

You can switch the compressor off and breathe through the bypass (I assume the bypass on that model is vacuum operated?). Or drive the SC full-time and just open the supercharger bypass for times no boost is needed, reducing power loss driving the supercharger but simplifying the drive. This would require the bypass to be electronically controlled (perhaps using the VVT function and table) for switching bypass at any load or speed. Several ways to approach it.

As superchargers increase boost with rpm, you are using a device that works better at higher rpm, for only lower rpm. A small quick-spool turbo sized for your target range would seem a more efficient power adder, but likely worthwhile in any case. Sounds like a fun project, and have fun!

A turbo is too much work and money. one has to get an exhaust manifold, new downpipe, new exhaust design, oilpiping ...
A supercharger is just bolted on like an alternator. I just need to order a new crankpulley for the belt (50€) and weld a bracket..
Superchargers kick in at lower revs compared to turbos but loose against the turbo at higher RPM in efficency.
You achieve higher end-HP with a turbo.
With a turbo you can't have 2 bar boost at idle

I can get a supercharge installed in a couple of hours (welding the bracket) and changin the crank pulley for a total cost of 200€ (not including the airduct of course)
A turbo with manifold is expensive and takes days with exhaustfarication...

here a supercharger link I haven't looked into it to deep how it works with the flaps.
but yes there has to be a bypass-flap when the supercharger is off.

here a supercharger "damper" only

they have a certain displacement per rev, so I can just calculate the pulley sizes.

here an eaton supercharger in an MX5 without airflap bypass

lot's of people are having fun with cheap superchargers, search for eaton M45, M62, M65 ...

here is an AMR500 supercharger (500cc per rev) which would be a nice samurai package
(once finished with the lada I will bolt a AMR300 onto my 200cc motorbike with a speeduino)

52MM "Big Bubba" Blowoff Valve
I won't be going with "Big Bubba", but some cheap ebay replacement.

[huramentzefix]

what is the secret with the colors in this forum?
links are black, the text is very dark grey?

leaf-blower supercharged tacoma

[huramentzefix]

AMR500 Suzuki Sidekick with a good illustration of the working pop-off-valve

[huramentzefix]

https://www.youtube.com/watch?v=fISNzaYz0So
the AMR500 is good to about 1500cc max. It would be sufficient for what I have in mind with boost at just below 2200RPM.
But the mercedes CLK eaton M62 comes with a nice magnetic clutch, has more volume and cost the same.

[runesm]

Boosting stock engines is often a compromise of horsepower goal, and durability goal.
Usually, if you want a stock engine to perform boosted, and last, you boost very low in low revs, and then ramp up the boost. Its the high cylinderpressure combined with lack of revs that breaks stuff.

What you want is a diesel-like performance, and even if you could control the supercharger like that, engine will 100% guaranteed break.

Controlling it on-off and just boosting 0,3-0,5bar is probably your best bet, and will net you a nice gain of 20-50% if tuned right. Maybe even just tuning it standalone and NA will net you some gains.

[PSIG]

Dude, use whatever you think will work best, or whatever you like, for any reasons you like. This is not an argument of which blower is awesome or crap - it was(?) a discussion of general points, principles, and perspective to approach your stated goals in different ways that could help in best success. Well, it was for me, anyway.

My story of the Samurai was not a social discussion or "do it this way", but to begin looking at the pros and cons of real-world results of similar projects and goals, and how one or another approach worked well (or not) and why.


That info might be helpful to your project. From this, is there a way to configure your SC to be even more effective with your needed boost profile? I have other projects I have done that are also similar, that could be of interest to you for how they worked better or worse, and could benefit your project success. An LQ3 5.7L low-rpm boosted street truck comes to mind that held a lot of lessons for me.

I don't care what you use, but I hope you succeed. You do not need to be defensive about your favorite stuff, as I discuss on technical points and merits, not which one you like to pet. I would appreciate if you are going to argue instead of discuss, that you get more general facts right, or accept other ways they could work that are not typical. I don't argue what color people like, but I'll discuss what colors might have benefits for a purpose, if you see what I mean. Having done a lot of this stuff for many years, I try to help users help themselves to get to where they are happy, quicker and/or better. Well, that's my intent anyway, and that does not appear to be happening here. Let us know how it goes.