Hello guys, thanks for all your welcome backs. It is great to see so many of you I remember well still around.
Quack....This turned out to be a bit of a longer post than expected!
Seems like lots of you are interested in the charger drive power. It is easy to work out and can be done for any charger.
You need to know the pulley ratio, flow per revolution of charger, boost map (or efficiency at stated RPM) and your inlet boost pressure.
To give you an idea check out a screenshot of the spreadsheet I created below (click the thumbnails). If anyone wants this xls file please shout.
BTW does anyone know the efficiency of a G-Lader and the flow per rev?? I will post one for a G-lader should I get the data.
The M45 flows 750cc per revolution.
Its boost map is available (see thumbnail)
At 7000 RPM on my setup the charger is doing just over 15000 rpm and has an efficiency of 50% (see boost map in one of my polo albums below, -please tell me should it not work)
At 8000RPM the eaton is an estimated 45% efficient (maybe lower, it is not on the map) and draws 59.8HP from me engine (check out the northern twang!).
Put the boost up and charger power gets even higher, this is the reason many eaton setups are pulling 20+ PSI and struggling to go much above 200BHP. Longer overlap and good flow matching is needed to get inlet boost into the cylinders. It drops pressure ratio, increases charger efficiency and takes less from the engine.
You can see the power curve shows no timing advance. Looking at the torque curve you can also see the ecu switching to static mixture mode at 6500RPM (The G40 did not have a timing advance data table above 6500 as this was the rev limit, timing above this rpm remains fixed at one setting hence the dip in torque. I think an aftermarket ECU would give good gains here but you really don't need it.
The little polo is in a fairly hefty state of tweakage and I have done lots of little bits that all add up to give a useable, torquey setup. I can always get full power when dry on the tarmac in 2nd, I did do it once in 1st but only once! (the diff is a little bit harsh -I am on that one though) When it is wet 3rd, and if bumpy will spin both wheels in 4th!
I have a great crack in my chassis that I found today to illustrate how nippy the little motor is too!
(Bastard thing, I wouldn't mind but my chassis has had lots and lots of attention and reinforcement. Now it needs some more......)
I really don't think that my 50HP to turn the eaton has been wasted.
Since the remap the car is way way quicker. Power comes in hard from 3000 and peak torque now feels at 5500rpm and is savage (best way to describe is it feels like your 2nd turbo just kicked in). The car pulls equally hard really from 3500-8000 apart from the peak where it pulls plenty harder. I don't really drive it above 7K much unless.. erm driving enthusiastically alongside some erm middle aged bloke in his 50K motor with my shopping trolley!
for the sake of engine longevity.
I do need to get it back on the rollers to prove out what power she is putting out. My estimate is 240BHP and potentially 260 on a cold day. This means the engine is pulling in the region of 300BHP before charger losses.
Fire!
To be honest it is too quick for the road (if you can fathom that) and on a cold day still scares the crap out of me.
I do look forward to taking it down the strip should I ever get around to it. Shame it cant be when it is cold.
I would like to see a gearbox that can handle 300BHP and I am sure the engine would be fine for it on a turbo setup.
As for the beauty of an eaton, should you see me I will take you for a spin, just ask.
The charm is good grunt and lack of lag whilst getting the power curve of a good turbo car with almost the low down torque of a G-lader. The G40 unit runs out of real good puff around 170BHP where it can still maintain optimum driveability, above this it starts to feel less progressive. Going back to a quick G always feels a little flat vs an eaton even though they are very potent cars and probably better for everyday driving. Then we have turbos that have to be kept in their happy zone and are in my opinion not even near as responsive when coming on the gas.
Meanwhile I do have to figure out how to quieten my eaton whine (you guys are for sure right about that!) should be easy, - as I seem to be an acoustic design engineer for a living......
If anyone wants some files/pointers on the boost/charger power thing I would be happy to help.
All the best, later guys.
Quack.