I just completed my first long road trip in the GT40 – 1400 miles through the Canadian Rockies to Calgary Alberta and back.
I drove the car there for its 3000 mile check plus an engine tune. My engine was built to spec by Western Motor Sports of Calgary and I wanted them to check my installation. I also arranged for a tuning session for the SDS on a chassis dyno.
The car handled well at highway speeds on the very, very rough roads – I got a little sore in the rear after the constant pounding; only thing that came loose was a harness clamp and an acorn nut on one of the side vents. The car got pretty dirty so I visited the local fire hall to use their vehicle washing bay.
Not many problems were found – bad coolant hose routing (lucky to find the gash almost completely though the hose at the shop rather than en route in one of the many mountain passes), minor fuel leak and fast idle orifice problem (not big enough). Also got a bunch of suggested improvements – plug wires, oil filler location, heat protection for the remote oil lines, crankcase venting and air filter.
SDS engine management program was tuned on the dyno.
On the way home, I drove winding up and down roads at speed through an horrific rain storm. Got wet feet!! Looks like there is a leak at the front bulkhead (probably where steering shaft passes through) and from somewhere else that soaked the carpet behind driver’s seat! Also a heavy overnight rain highlighted the fact that the light covers and windows don’t seal – lots of moisture and haze on the inside.
That’s the good news – all of that can be remedied; now the bad.
I need some help/input from you guys.
PROBLEM #1:
On the return trip, I noticed that the rear end would drift, skate, feel like it was on ice (can’t properly describe it) whenever I downshifted on a downslope (and there were lots of those, the longest of which was 20km @ 6 degrees) at any medium to high speed with no brake, no throttle and engine was braking/decelerating. Real uncomfortable/scary feeling. I was afraid to “punch it” or drive hard so it kept me on my toes for the last 2 hours of driving. As soon as I got back on the gas (lightly) it straightened right out. Rear end felt really light and “wobbly”. When I got home I checked for the obvious – a loose component in the front or rear suspension – trailing arms, shocks, A-arms, etc.; nothing obvious.
Any ideas?? Could it be something in the transaxle? Bad camber? Tires?
PROBLEM #2:
Ever since day one, I have felt what I thought was an engine stutter/lugging in low (1500-2400) rpm, no load situations. I have tried every combination of ignition and SDS tuning known to (this) man to try to fix the problem – to no affect. I have learned to always drive above 2400 rpm in all gears!! That was one of the reasons to go to Calgary to have the engine builder look at it.
During the intensive dyno work (4 hours), it became obvious the car was “porpoising” front to back with low throttle at low rpms. As I ran the engine up slowly to 4th gear, the car would bob up and down at the front with the rear end tied down on the dyno. My engine builder (and quality race car driver) suggested that it appeared to be suspension related. He noted that the rear springs are fairly compressed and have less than ¼ inch till they bottom out. He also said that some racers have had unusual experiences with Goodyear F1 tires and that the combination could be contributing to the problem.
So -> could it be the shocks, the rear end set up (camber, caster etc.), tires, rear springs/spring rate, front/rear spring combination.
Any input greatly appreciated.
All in all a great experience; I plan on many more road trips once I get all the little problems fixed.
I drove the car there for its 3000 mile check plus an engine tune. My engine was built to spec by Western Motor Sports of Calgary and I wanted them to check my installation. I also arranged for a tuning session for the SDS on a chassis dyno.
The car handled well at highway speeds on the very, very rough roads – I got a little sore in the rear after the constant pounding; only thing that came loose was a harness clamp and an acorn nut on one of the side vents. The car got pretty dirty so I visited the local fire hall to use their vehicle washing bay.
Not many problems were found – bad coolant hose routing (lucky to find the gash almost completely though the hose at the shop rather than en route in one of the many mountain passes), minor fuel leak and fast idle orifice problem (not big enough). Also got a bunch of suggested improvements – plug wires, oil filler location, heat protection for the remote oil lines, crankcase venting and air filter.
SDS engine management program was tuned on the dyno.
On the way home, I drove winding up and down roads at speed through an horrific rain storm. Got wet feet!! Looks like there is a leak at the front bulkhead (probably where steering shaft passes through) and from somewhere else that soaked the carpet behind driver’s seat! Also a heavy overnight rain highlighted the fact that the light covers and windows don’t seal – lots of moisture and haze on the inside.
That’s the good news – all of that can be remedied; now the bad.
I need some help/input from you guys.
PROBLEM #1:
On the return trip, I noticed that the rear end would drift, skate, feel like it was on ice (can’t properly describe it) whenever I downshifted on a downslope (and there were lots of those, the longest of which was 20km @ 6 degrees) at any medium to high speed with no brake, no throttle and engine was braking/decelerating. Real uncomfortable/scary feeling. I was afraid to “punch it” or drive hard so it kept me on my toes for the last 2 hours of driving. As soon as I got back on the gas (lightly) it straightened right out. Rear end felt really light and “wobbly”. When I got home I checked for the obvious – a loose component in the front or rear suspension – trailing arms, shocks, A-arms, etc.; nothing obvious.
Any ideas?? Could it be something in the transaxle? Bad camber? Tires?
PROBLEM #2:
Ever since day one, I have felt what I thought was an engine stutter/lugging in low (1500-2400) rpm, no load situations. I have tried every combination of ignition and SDS tuning known to (this) man to try to fix the problem – to no affect. I have learned to always drive above 2400 rpm in all gears!! That was one of the reasons to go to Calgary to have the engine builder look at it.
During the intensive dyno work (4 hours), it became obvious the car was “porpoising” front to back with low throttle at low rpms. As I ran the engine up slowly to 4th gear, the car would bob up and down at the front with the rear end tied down on the dyno. My engine builder (and quality race car driver) suggested that it appeared to be suspension related. He noted that the rear springs are fairly compressed and have less than ¼ inch till they bottom out. He also said that some racers have had unusual experiences with Goodyear F1 tires and that the combination could be contributing to the problem.
So -> could it be the shocks, the rear end set up (camber, caster etc.), tires, rear springs/spring rate, front/rear spring combination.
Any input greatly appreciated.
All in all a great experience; I plan on many more road trips once I get all the little problems fixed.
