An Evo IX with a full exhaust has a dyno plot before and after a fuel pump, remap and boost controller are fitted.

The ignition and valve timing are unchanged.

At 6000 RPM, we have the following:

BEFORE: 257 WHP at 1.24 bar, 0.78 lambda
AFTER: 300 WHP at 1.33 bar, 0.76 lambda

Atmo pressure was 0.98, so we have absolute manifold pressures of BEFORE 2.22 bar and AFTER 2.31 bar.

In an engine of approx 2 litres, we have the following WHP/litre/bar absolute (as a measurement of efficiency):

BEFORE: 257/2/2.22 = 58 WHP/litre/bar absolute
AFTER: 300/2/2.31 = 65 WHP/litre/bar absolute

Where does the extra 12% efficiency come from? Remember the ignition and valve timing are unchanged.

Doing the same sums at 5000 RPM gives a 10% extra efficiency which I also can't explain.

Discuss.

 

Well the only thing I can think of is the boost went up about a pound to pound and a half....IDK.....BUMP!

 

oops

 

Do you have a MAP log for before and after?. If the MBC allowed you to hold the 1.33 bar to redline, I see about 30-40 whp right there, with the taper on the stock IX. The extra psi or so from before/after on top of that is another 10 HP.

Also, did the previous run have any knock? Pulled timing would obviously net lower numbers.


Eric

 

Was the fuel pressure higher with the install of the new pump? If so, it's possible the higher fuel pressure may have led to better atomization of the fuel.

 

your looking at peak numbers, I bet the average of both torque curves (sum of area beneath line) throughout rpm range will give you the correct mathmaticvl answer

 

This was before I got the car so I don't have logs.

I'm looking across the range and the pattern is similar. The after plot has a considerable increase in efficiency.

The MAP readings are taken off the dyno plots at the same RPM points I'm reading the power numbers.

The exhaust is unchanged - 3" elbow back decat.

Yes the new pump could run higher pressure and atomise better, but the fuel maps and AFR would suggest there is little change in fuel pressure.

I'm wondering if anyone is as cynical as me...

 

Here are the WHP before-after charts, one with lambda and one with boost. See the whole curves tell the same story...

http://john824.fotopic.net/p28539238.html

http://john824.fotopic.net/p28539237.html

 

Holyschit, that graph was increased a %age throughout as if you just enlarged and moved the line up.

Was run done on same day, fuel, airfilter, soforth - maybe you were in lo oct mode for some un Godly reason the first time before the boost

Cynical or skeptical? Cynical on the mitsu engineering (or denso hehe), whats your ultimate statement?

It could be a decent claim to say that the 43 whp increase was obtained from
1) 1psi boost increase
2) running hi Oct maps (did you have lambda reading thhe first time?)

Unless fuel regulation trouble prior, then what else can it be?

Nice gallery, that pic shows that you need to catch some oil vapors before they reach the turbo


Wait one second: What about tire (excuse me - tyre) pressure and size, were they the same?

 

The boost increase likely put you in different load cells, so although you may not have adjusted the ignition timing table, the car is running different ignition timing. If the before pull was seeing a lot of knock and pulling timing but the second was not that could explain the power difference. That's the only thing I can think of to explain it (other than environmental changes).

-Paul

 

Although I don't have logs of these runs since they were before Evoscan and before I had the car, the standard map on this car is very safe and runs fully off the high octane maps with trivial knock sums. On the remap running higher load it would be running less ignition timing.

I can't think of any other variables related to real power output, it was the same tank of fuel, same day, same airfilter, same exhaust, just the fuel pump, boost change and the fuel maps were tweaked slightly (although not much and I think they're worse afterwards from the plots).

My opinion is that the 43WHP comprises:

At most 10 WHP from the extra boost (assuming the same efficiency)

At least 33 WHP from the lower drag on the transmission from the heating of the transmission oil from repeated runs. I suspect that the worst and best dyno plots have also been selected for the before-after presentation to the customer.

I know you guys in the US like WHP figures, but the above is part of the reason I like the coastdown run and extrapolated flywheel figures. During a dyno session the flywheel figures appear to stay consistent as long as you keep the engine temps under control.

 

C6C6, the breather deposits were there at only 5000 miles and the car had been never running more than the boost shown on the plots at that point. I think the HKS panel filter maybe let go of some of its goo which makes the oil stick down. It takes good ignition timing so I've not done anything with it, and it doesn't use oil. It shows up a lot in that hard pipe and with the camera flash.

 

it's gotta be an anomaly.

 

I have another example from the same rollers -

5500 RPM, 228 WHP & 0.73 lambda before, 268 WHP & 0.78 lambda after, the BOOST WAS THE SAME.

Not my car, don't know what the ignition timing was but there were no other changes except a map I believe. I can believe that 0.05 change in lambda would give perhaps up to 10 WHP gain, maybe another 10 WHP if they played with ignition (just pump fuel by the way).

 

So over there you get a guy who used to freeze chickens for a living and me replying. OK so DaveG has amassed quite a bit of knolwage about turbos, but the thought of him in a ***** Wonka style cooling silo made me laugh.

MB