The alternator problem was caused by a blown 100A fuse between the battery and alternator. I'm fairly sure I did that when I was snaking the external battery connector out of the sidepod and shorted the battery connectors together.
The alternator itself is an ordinary Denso unit, and the local alternator shop is rebuilding it for me. He promised to use high grade parts since it spins at 8000 rpm at times. I'm also converting it to a self-exciting version with an internal regulator of 14.5V.
I'm gonna move the fuse to a spot where I can inspect it without having to remove the sidepod. 🙂
The alternator problem was caused by a blown 100A fuse between the battery and alternator. I'm fairly sure I did that when I was snaking the external battery connector out of the sidepod and shorted the battery connectors together.
The alternator itself is an ordinary Denso unit, and the local alternator shop is rebuilding it for me. He promised to use high grade parts since it spins at 8000 rpm at times. I'm also converting it to a self-exciting version with an internal regulator of 14.5V.
I'm gonna move the fuse to a spot where I can inspect it without having to remove the sidepod. 🙂
That fuse is a bummer !!! Had it blowing twice on my SR3 (one with a single battery) and once on a customer SR3 with twin batteries... First thing to look at if you notice alternator is not charging but so easy to miss ! The one on the SR3 is 30 A IIRC. Strange that they located it in the sidepod on SR8...
That fuse is a bummer !!! Had it blowing twice on my SR3 (one with a single battery) and once on a customer SR3 with twin batteries... First thing to look at if you notice alternator is not charging but so easy to miss ! The one on the SR3 is 30 A IIRC. Strange that they located it in the sidepod on SR8...
I'm not sure of anything on this car as far as how Radical originally built it. It's quite possible that the fuse was relocated by some maintenance action along the way. In any case, that's fixed now. And yes, very easy to miss, especially when one keeps the car on a maintenance charger!
One other thought: why 100A? The alternator puts out a max of maybe 50A. I wonder if the car was blowing fuses and a frustrated mechanic along the way bumped the number to 100A...
That fuse is a bummer !!! Had it blowing twice on my SR3 (one with a single battery) and once on a customer SR3 with twin batteries... First thing to look at if you notice alternator is not charging but so easy to miss ! The one on the SR3 is 30 A IIRC. Strange that they located it in the sidepod on SR8...
I'm not sure of anything on this car as far as how Radical originally built it. It's quite possible that the fuse was relocated by some maintenance action along the way. In any case, that's fixed now. And yes, very easy to miss, especially when one keeps the car on a maintenance charger!
One other thought: why 100A? The alternator puts out a max of maybe 50A. I wonder if the car was blowing fuses and a frustrated mechanic along the way bumped the number to 100A...
I see... Yes 100 Amps sounds like a LOT for this job... Dangerous even if it's meant to protect a circuit and blow at lower amps... Have you checked on the electrical drawings what it's supposed to be ? I may have some SR8 electrical drawings but I think only for the older ones. Having said that it may not have changed.
That fuse is a bummer !!! Had it blowing twice on my SR3 (one with a single battery) and once on a customer SR3 with twin batteries... First thing to look at if you notice alternator is not charging but so easy to miss ! The one on the SR3 is 30 A IIRC. Strange that they located it in the sidepod on SR8...
I'm not sure of anything on this car as far as how Radical originally built it. It's quite possible that the fuse was relocated by some maintenance action along the way. In any case, that's fixed now. And yes, very easy to miss, especially when one keeps the car on a maintenance charger!
One other thought: why 100A? The alternator puts out a max of maybe 50A. I wonder if the car was blowing fuses and a frustrated mechanic along the way bumped the number to 100A...
I see... Yes 100 Amps sounds like a LOT for this job... Dangerous even if it's meant to protect a circuit and blow at lower amps... Have you checked on the electrical drawings what it's supposed to be ? I may have some SR8 electrical drawings but I think only for the older ones. Having said that it may not have changed.
Electrical drawings would be most welcome! My car is a 2007...
This morning's dyno session went much better than last time. The alternator, throttles, and fuel pump worked perfectly today, and I was able to flesh out the rest of the fuel map. The MoTeC-led RPB makes somewhere around 375 hp at the tires at 10k rpm, which matches perfectly with the 440 hp as advertised by Radical.
The car is finally ready, and I'll be out at Sebring on Saturday!!
Congratulations John. I’m glad to see this beast is breathing fire again! I am looking forward to hearing about your time on the track with it.
Charley
This past weekend was track time. I ran 10 sessions over the weekend, and the car was a blast. I had some throttle problems, but was able to resolve them by mid-day Saturday, and it was all about driving from that point on. I've got a LOT to learn on that front.
I ran at SIR (Sebring Int'l Raceway) and posted times that slowly improved over the weekend. I met an SR3 driver with vast experience who was at least 10s faster than me, so I've got a goal now. 🙂 I'm not gonna be too hard on myself -- this was the first time I've driven the car on a dry track in a run group filled with guys who are very very quick.
I think I can say that this MoTeC project has been successful, and the car came home no worse for wear. Now for normal maintenance (oil / gear lube / brakes / half-shafts / etc.
Shifting (the original goal) is smooth and easy, both up and down. I found myself able to downshift as I approached the apex without it upsetting the car. Turns 17 and 1 are too fast to get from 6th to 4th prior to turn-in, so I would get to 5th before turn-in then 4th as I eased off the trail braking. Back on the throttle as the apex approached and away. The joy of paddle-shifting.
One concern: as I got faster, the gearbox got hotter, and the clutch started to get sticky. Coming back in after a session was tricky without being able to completely disengage the clutch. Anybody else have this issue?
I’m glad to hear that you got the car back on track again! Sounds like a good clutch bleeding is a good place to start.
Charley
thanks Charley!
My wallet and I are really looking forward to a normal experience with the car from now on. I've got a whole bunch of normal maintenance items to do to get ready for my next event. Clutch bleeding is definitely on the list.
I'm bringing this old thread back to life... I'm swapping my MoTeC DBW sequential EFI RPB into my 2009 SR8. But I'm incapable of leaving well enough alone. 😮
I was never happy with how the linkage connected to the DBW actuator. There were always minor differences from bank to bank (2 to 4% or so) which the ECU compensated for, but worse was that you could see the throttle blade inertia causing differences up and down the banks. Cylinder 4 was the end of the whole chain and was the last to move in either direction. Careful setup improved it, but it annoyed me. Also -- the MoTeC ECU supports dual throttle actuators.
Hence the new setup. I'm changing the linkage to be in the middle of the banks. Now the farthest away throttle blade is just one away from the actuator (it used to be 5 away). I'm hopeful for a more synchronized engine.. though I doubt I'll see any improvements in lap times. 🤣
Hi John,
Very impressed with all the mods you have done. I’m surprised Jenvey didn’t tell you about the linkage they made to get rid of the short cable between the 2 banks. But looks like you have got around it with the dual dbw motors, great idea going from the centres.
The clutch issues were very common, as in every single race weekend common. The slave cylinder was essentially getting too hot and the piston was seizing up, destroying the release bearing and the clutch fingers in the process. Check the clearance between release bearing and fingers, you may find it’s far too close. Personally I’d change the slave cylinder to Tilton or AP and start again with the spacer. I don’t think the design of the spacer is great for heat dissipation, the hewland setup (which has never had the same issue) has 3 lugs for mounting to the gearbox and steps down in diameter, and back up again for the slave cylinder mounts. Hope this helps if you haven’t already fixed the problem.
This dual actuator setup is a great idea! Well done.
I'm still running with a cable between the two banks, hopefully we'll upgrade to the rod system at some stage.
Thanks! It's track-proven now. Shifting with the RDS Geartronics firmware and MoTeC M150 is amazing. I've been able to tune any bank-to-bank differences, the car starts immediately, and I'm seeing about 380hp at the wheels.
Of course -- the original valve block failed last time out, so I'm upgrading that now. By the time I'm done I could have bought a new SR10. 🙁
What/who’s valve block are you using?
Yeah sure you probably could have bought an sr10, but they don’t sound anywhere near as good as the V8 🙂 And I think a good sr8 will have the edge over the sr10 on overall lap time, but I guess that will have to be proven.
I think the gearbox in the sr10 would be a good replacement for the sr8, hewland tmt. Sort of vaguely looked at that in the past but the car was running in Radical’s championship so that wasn’t possible. Would easily take the 380hp.
What spec engine are you running?
Alex
