Postby Hasbeen » 12 Mar 2013 02:38
Trixy, now even more of the belief that any problem is likely to be tuning, & that is the mixture at idle, & small throttle openings, at low revs.
Some time back I did an extended post on cooling the 8, with it's 4.6L, & airconditioning, but I can't find it now.
I chased it's cooling for about 6 years, keeping the thing just drivable, without air, in city traffic. A drive in the suburbs often required parking, engine off with the fans going for a while on a hot [35/40] day. Out on the open road it was never a major problem, but you never felt really on top of it.
It has a VN Commodore radiator, with a 4 core conversion, which I often thought of changing, but ultimately it proved quite OK.
During one of those strange turns my son sometimes takes, he bought & fitted a more highly worked inlet system, with a much bigger throttle body, bigger injectors, & a very high tech spark generating setup.
When the old Haltech would not let us in to tune it, he fitted the latest Haltech, & converted to computer controlled ignition, as well as injection.
The thing picked up a great deal of power, & I expected it would prove to be an even better water heater, but probably undrivable on the road. It is now difficult to get it away from a standstill, with out spinning wheels, until you've had some time to get the feel of it.
Not only does it now run so much cooler that you can drive it anywhere, in the comfort of airconditioning, but the economy is way better.
On a 2900Km run after the modifications it gave 10.1L/100Km, where 14L/100Km was hard to achieve previously. On one famous occasion, my son achieved 25L/100Km, without really trying, with the old setup.
The thing is tuned much richer at low revs, & small throttle openings, & as you now drive it on much smaller throttle openings, we have decided it was running lean in that area. Everything looked good on a dyno previously, but of course, you are using large throttle openings when tuning for power, & we never even thought to look at light loads.
The thing is now with my son, in Kiama. You should get together & swap notes. He has now fitter a much larger exhaust system from the extractors back, so I hope all the above is still true.
Hasbeen
