Ok boys and girls. A few pages back I said I would give you a subjective comparisom between the GXII and the MG66 once I had a bit of fuel through one of the new motors.
I have a GXII with 1.5 litres through it. It still has considerable metal pinch, but can just be turned over in the buggy by hand when hot, so I feel it is performing well enough to make a fair comparison between the two motors, allowing for the fact the GXII will free up some more with another couple of litres through it.
I spent an afternoon at the track with the following set up -
X-Ray 808 buggy, standard gearing, same as I run with my MG66
GXII motor running 25% fuel, stock shims, O'Donell 97T med temp plug, JVD 4 shoe clutch with 4 x alloy shoes and gold 1.0 springs, and Werks 2013 pipe.
Bottom end -
The GXII has more bottom end than the MG. This is obvious even with only 1.5 litres through it. The bottom end is sharp and snappy, but not like a light switch. The power is there on demand but the application is a steady pull of power. This is with the JVD clutch, which I don't run on the MG as I find it is too soft for most tracks I run on.
This clutch set up is perfect for the GXII in the buggy. Running a stock 3 shoe clutch with alloy shoes and 1.1 springs would make the GXII very similar to the GX-5R, so that's what I would run in truggy with the new motor.
As a reference, I used our six pack jump as the ultimate test for the bottom end comparison. With a nice straight run up the MG66 with three shoe clutch and 1.1 springs does the 3 and 3 jump easily, but if you get offline and have to slow too much before the jump, it is a 2 x 2 x 2 as I don't normally have the launch to clear it 3 x 3.
With the GXII it clears the 3 x 3 easily from any speed of appraoch. To prove a point to myself, I did several runs where I stopped completely about 5 metres short of the first jump, then gunned it. I cleared the 3 x 3 easily every time from a standing start. Remember, this is with the softer JVD 4 shoe clutch fitted, as opposed to the stronger 3 shoe fitted to the MG, plus limited fuel through the motor.
Mid and top end -
Here the motors are very similar. I would say at present with only 1.5 litres through the GXII that it has the mid and top end of the GX-7R.
I would say with more fuel through it, the GXII would be on a par with the MG for mid range power, and somewhere between the GX-7R and MG66 for top end - which is not a bad place to be.
Power application -
The GXII and the MG have a very similar power band. They both have smooth turbine like power that makes driving very easy. What you pull on the trigger is what you get directly and immediatly. There is no bottom or top end feel to either motor, just an instant response of power no matter where you are sitting in the rev range.
So to sum it up - the GXII once fully bedded in will be very much like the MG66, but with quite a bit more bottom end.
Buggy application - with mid range pipe and medium clutch set up = perfect
Truggy application - with a stronger clutch and long header pipe (like the 2072) = excellent.
I don't run a truggy presently, but have a lot to do with the truggy guys that run the GX-5R's purchased from us here at GO Racing NZ, so have a very good idea of how the new GXII will compare, going on what I have experianced with this motor so far (plus having run a GX-5R in my buggy for fun events on ocassions).
Well, that's as fair and impartial as I can be. Remember, I sell both motors, so have no reason to favour either model over the other one.
I have been racing the MG66 in my buggy since it's introduction (engine # 00031) so am very familiar with it, what clutch it likes etc, etc, so I think the comparison is a pretty fair one.
With it's extra bottom end the GXII will suit the tracks I run a little better I think.
I will be running it as my #1 motor this season.
And please remember - this is just my personal opinion, Others may disagree
