M103 detuned...?
I'm fairly certain that someone posted a remark about the M103 in a G being a "detuned" version of the M103 in a car. Can't remember who posted it or what exactly what was written. Did a search and can't find it either. Any ideas anyone? I'm keen to know more about this.
Thanks
Whirr whirr ching ching - could it be this - http://www.gwoa.co.uk/content/g300-thermostat
Arnie's comment No. 7 about half way down.
Hi Ian
There are two quite a lengthy and detailed threads about turbo charging a M103 engine in these links...
http://www.peachparts.com/shopforum/performance-paddock/251302-190e-3-0-...
http://www.peachparts.com/shopforum/performance-paddock/174080-300e-12v-...
Although they relate to saloons rather than the G you might find them useful. They have apparently been getting over 600hp out of the M103 on standard internals .
The first link is fixed now.
i think that there is very little difference between 9.1 and 9.2. Gasoline engines use a throttle so the cylinder is hardly ever 'full' of air to begin with. The amount of air compressed depends on the throttle position. A CR of 10:1 is more normal for a high-performance, naturally aspirated engine., so going to 9.1: 1 or 9.2: 1 would make little difference, I think. If pre-ignition is a concern, just use higher grade fuel. The premium fuels will give higher mileage anyway. Or you can change the resistance plug to set the engine ignition timing for a lower octane.
As for making a gasket. you can work out the compressed cylinder volume (1/6 x 2960 / 9.2) in CC and then work out the effective cylinder compressed length from that = (Pi x r^2 x L), where r is the cylinder radius ( = [88.5 mm / 2], I think - need to check)
so, L1 = (1/6 x 2960 x 1000 / 9.2) / ( Pi x r2 ) (note x 1000 to convert CC into mm3)
Then, do the same for a CR of 9.1:
L2 = (1/6 x 2960 x 1000 / 9.1) / ( Pi x r2 )
required gasket thickness = ( L2 - L1 ) in mm
Hi Ian
I know you said that you did not want to go down the aftermarket ecu / fuel injection route but that is the easiest way to control any issues with pre-ignition when running a turbo.
With a modern programmable ecu that can alter ignition timing to suit different levels of boost there is no longer the same need to reduce the compression ratio. I imagine that it might work out cheaper than the machine shop as well.
Sorry I'm asking, but do you think there is room for a t/c? I had a look into my car and it looks pretty full up with the a/c compressor, piping ABS module, alternator snorkel etc etc heat shields . I am told that for this engine, "porting" and changing the inlet valves is probably a better way to boost up. No major surgery, running gear remains the same , no special lubrication or cooling. Unfortunately there is no way of re-mapping the ECU, otherwise this would have been probably the less painful way of acquiring the extra horses.
I assume that a 3.2 24v transplant is not the answer to the question of more power?
No contest then!
I did have a M103 engined Mercedes for 5 years and the only problem I encountered with it was distributor caps. It needed a new one every 12k miles.
Good luck with the installation - it is nice to see upgrades on a petrol G.
The 3.2 m104 engine would not be compatible with the ke-jet system in the ge300, it would need the head off a m104 24v 3 litre engine which is k-jet, altogether too much fuss.
Forced induction is better at giving the torque needed in a hefty vehicle.
The higher octane fuel now available might mitigate the need to fit shortened con rods as specified in the original conversion. I belief the highest octane fuel now available is higher than that available in the late 80's when TT conceived the system
the instructions for fitting insist on what was then 98 octane fuel
http://www.supercars.net/cars/4531.html
http://forums.mercedesclub.org.uk/archive/index.php/t-38989.html
I'm pretty sure its in the paperwork, but the advantage is less work modifying the pistons or shortening the con rods
I've probably got this wrong, but I thought lower octane fuel was better when running turbo chargers...??
From what I understand Octane Rating is a measure of how much a fuel can be compressed before it detonates without an ignition source.
High performance engines, normally aspirated or turbo charged, need a higher octane fuel because of the higher compression and increased heat they generate which would cause detonation (knocking) with a lower rated fuel.
You can get around the detonation problem with standard fuel by retarding the ignition (which is what a modern ecu does) but then the engine is not running at its optimum level of performance.
Whirr whirr ching ching - could it be this - http://www.gwoa.co.uk/content/g300-thermostat
Arnie's comment No. 7 about half way down.