Verb04

The one that offers the most HP gain. How much is it? Where can I order one??
Thanks

tifosiv122

As far as I know there is no retail one out yet.

Erik

Verb04

Is anyone planning on makeing one? They gain you get on the 2.3K is amazing. I hope the gain on the 1.8K is just as impresive.

TimmyC230boy

It took about a year after the release of the 2.3L for a pulley, so in about another 9-12 months you should start looking for one.

Buellwinkle

Timmy, that may optomitic as the SLK230 and C230K sedans with the same exact motor/pulley as the coupes came out in March 2000 so it took about 2 years for that pulley to come out and even then they were already experienced from the pre-2000 2.3L motors in the older SLK230 and C230K sedans since 1997. The 1.8L is a totally new motor and unless someone takes the initiative and does it themselves I don't think a year is realistic.

trench

I agree with Buell. Plus, don't forget, supposedly the 1.8L (230K version) already is supposedly boosted to around 11psi stock (compared to the 5 psi of the 2.3). As best we've been able to determine, MB varies the power output of the kompressor versions of the M271 motor simply by changing the amount of boost (the 1.8L 200K motor probably has around 6-7 psi, etc.) Since the boost is already so high this could be a problem. Although, one thing worth looking into is that the 11psi 1.8L apparently uses the same intercooler as the 5psi 2.3L - simply changing this should therefore provide more power as a stand alone bolt-on for the new engine (than would be achieved on the 2.3L).

Cheers, BT

Lynn

https://mbworld.org/forums/showthrea...ghlight=pulley

trench

Hadn't seen that thread (Lucas usually knows what he's talking about). Surpised to see that the 46 hp difference between the 180K and 230K is due to software alone. The easiest way to do this would be the for lower powered ones to get less fuel at all engine speeds - which also improves fuel economy at the same time.

- BT

DCXdynodog

Not surprising at all, superchargers and turbochargers make variable hp easy using a bypass or wastgate to vary the air pumped into the engine and this engine does have a bypass as far as I know.

If they are doing it with software (via the calibration of the ECU), they would control the bypass valve to control the boost. Absolutely no reason not to do it this way, saves a lot of cash to build just one engine.

You can't just vary the fuel alone, the fuel/air ratio must remain constant thus if you push less air into the engine, the cal will put less fuel in to go with it. So under heavy throttle conditions, yes, fuel economy will be better (but the car won't accelerate as good either).

But at cruising speeds your fuel economy will not change because it takes X amount of power to move the car and the engine is the same (so internal friction and pumping losses are the same) thus it will use the same amount of fuel.

trench

I assumed that the engine's ability to ingest air would be reduced concurrently with a reducton of fuel flow - if the computer puts in less fuel the engine will be unable to rev as quickly reducing the need for additional air to keep stoichiometry constant. I guess I'm basing my assumptions partly on thinking about the way the rev-limiter works, which is a fuel cut-off.

You're saying it's more likely that the computer just opens the bypass to bleed excess air into the exhaust to reduce the fuel consuption/power. I defer to your expertise since you actually are an automotive engineer and not a wanabee like myself.

Of course, any changes in fuel economy will only be realized during acceleration (as long as the gearing is the same between the different versions).

Cheers, BT

DCXdynodog

Why are you calling me names? No engineer here, I just have to work with em

Rev limiters using injectors basically shut off fuel completely to one cylinder at a time in a rotation to maintain engine speed, the air still moves through the engine. On our cars they could just close the electronic throttle for a rev limiter. (I don't know if is the case)

If you just lowered the fuel rate at high loads, you would reach a point where temps would go up and detonation would occur. (engine and owner not happy at this point) If it gets lean enough and passes through that point and won't hurt itself but combustion fails, the engine misfires and hydrocarbon emissions go way up.

The bypasses on superchargers recirculate air back into the inlet side of the blower, so the air just goes in a circle instead of into the engine. This helps part throttle effeciency because it takes less power to turn the blower than if it was working to make boost all the time. It also gives the calibrator control over the airflow into the engine (boost) and they can use that to control power / driveability.

Turbos are different since they use exhaust heat and flow to drive a turbine wheel which drives the compressor, they generally use a bleed valve (wastegate) in the exhaust to bypass the turbine part of the turbo. This would be analogous to a variable size pulley on a crank driven supercharger without a bypass.