ExRotary

It seems that Mitsubishi has given up on performance cars to concentrate on other priorities. In the meantime Mercedes with their AMG tuning arm have moved into the space with the A45 and/or depending on market CLA 45. Here the A45 sells for about 15% over the MR.

The A45 has the highest specific power output of any production car in the market today at 133kW(178hp)/litre and they seem to be good for sub 13 second 1/4 miles off the showroom floor.

Now before I get buried with details of modified EVOs that will better this, sometimes by massive margins, let me say that I am not aware of any EVO achieving 350 hp the way that the A45 does. The Mercedes marketing department has produced this air brushed wet dream:



As if dyno charts are that smooth in real life Note the torque curve, maximum torque is in at 2250 rpm and hangs in there to 5750. But this doesn't seem to be too far from the mark. If you poke around the net you will find any number of independently generated charts such as the one below. The black line is the stock tune.



You can see from the tuner’s chart above that the A45's flat torque curve has been generated by keeping boost pressure flat after it gets to the desired level. For the tuned version the tuner has allowed the boost pressure to continue to increase to a higher level at around 3,500 rpm to get a more EVO like torque curve. But the thing is that the A45's stock boost level is 1.8 Bar (26psi) and this is being achieved at 2250 rpm. This early spool up is not achieved by a small turbo that goes on to quickly run out of puff. Even with the stock tune the A45 gets past 5,500 rpm before torque drops away! Looking at the tuned version it may be possible to get the turbo to hang in at 26 psi past 6500 rpm.

The stock EVO torque curve peaks about 3,500 rpm and 21 psi boost and then falls away to the red line. Tuning doesn't seem to do much to the curve before 3,500 but allows the turbo to continue to spool up to producing a higher peak further up the rev range. Going to bigger turbos moves the torque curve further up the rev range.

For a number of years VW, Audi and BMW have been on a similar path in bringing turbo boost in early and being able to hold boost through the rev range. It makes for a good drive on the road. The Japanese makers seem to be getting left behind in this respect.

So here is the challenge; with the tuning talent on this forum, why can’t we match AMG? Else, if it is too hard maybe we should just line up at the Mercedes dealership.

Mystykalbaby

Very insightful!

ExRotary

There are not a lot of details about the A45 turbo out there. Seems to be a Borg Warner (ex KKK) B03 twin scroll unit which is about as handy as knowing that the EVO X has a TD05 turbo.

In any case it must have a fat, fat, fat compressor map. You would have to think that there would be some fancy wastegating going on to boot.

Enclavet

I think its the twin scroll unit that is able to achieve fast spool with still top end performance. That a probably some mid range cams. I really dont see what is so impressive about it when you get a car with a similarly sized turbo with all the modern improvements like variable vane, twin scroll etc....

Has anyone actually tried using a smaller EFR in their 2.0? I would assume similar results.