Finally got out this week-end to get some real seat time on the sled. Up until now most of the riding has been on our test track (1/2 mile at a time) to test various parts of the design. We shot a piece of welding rod through the turbine blades a few weeks ago after making a new exhaust system (though I'd cleaned the exhaust thouroughly inside, must have missed a piece).
Anyway, after some final wastegate adjustments we're showing a nice even 6lbs boost. The manual boost controller worked well also, 10lbs can easily be dialed up while still riding the sled. Doesn't look like we'll be needing 10lbs though... Even at 6lbs a setup that would barely pull 10k rpm pre-turbo is bouncing off the rev limiter almost immediately. The Pop-off valve seems to work well, and throttle response is excellent. Boost spools up pretty quick, and the 1.25 Ripsaw along with a Cat ZR skid underneath are doing a decent job of getting power to the ground. Didn't touch the skid this week-end, but it will need a little more ride-in, and a bit more pre-load on the front.
One of the problems we were having initially was oil getting past the seals in the turbo. Originally thought that 60+PSI was a little high for a turbo (and it is) so we'd been running a .045" restrictor in the supply line to bring oil pressure down to about 45PSI. That was working much better, but we still would occasionally get some oil in the exhaust/intake. We've since re-designed part of the oil return system and didn't see any signs of oil in either the exhaust or intake all week-end, and that was with the restrictor removed. I think this one is solved.
All of the electrical systems worked perfectly. The A/F guage shows the motor as a little lean down low, and progressively richer as boost comes on. Some quick adjustments with fuel pressure moved things in the right direction, but will probably require a little jetting as well. For now running fat is just fine with me. I have two LED's on the pod, one showing that the fuel pump is running, and the other hooked to a pressure switch that gets its air from the Fuel Pressure Regulator's boost line. When the motor sees 4LBS boost, the light comes on. If I see boost on the guage but no light to go with it, something bad is about to happen. I didn't like the idea of possibly smoking a motor because of a kinked hose or 20 cent clamp not doing it's job, and this seems like cheap insurance...
We took it fairly easy this week-end, starting boost off at 3 pounds then slowly adjusting it up to 6-7. Even with a poor clutch setup, the sled will walk up to 120 MPH indicated without effort. No question that with proper clutching and suspension set-up, the sled will see well in excess of 130 MPH on the speedo.
Overall, I would say the weekend was a success. Clutching this thing is going to be interesting, but I have a few ideas on where to start. The intercooler blew off once after coming off throttle, and the POV needs a quick tweak, but otherwise everything worked out really well.
Anyway, after some final wastegate adjustments we're showing a nice even 6lbs boost. The manual boost controller worked well also, 10lbs can easily be dialed up while still riding the sled. Doesn't look like we'll be needing 10lbs though... Even at 6lbs a setup that would barely pull 10k rpm pre-turbo is bouncing off the rev limiter almost immediately. The Pop-off valve seems to work well, and throttle response is excellent. Boost spools up pretty quick, and the 1.25 Ripsaw along with a Cat ZR skid underneath are doing a decent job of getting power to the ground. Didn't touch the skid this week-end, but it will need a little more ride-in, and a bit more pre-load on the front.
One of the problems we were having initially was oil getting past the seals in the turbo. Originally thought that 60+PSI was a little high for a turbo (and it is) so we'd been running a .045" restrictor in the supply line to bring oil pressure down to about 45PSI. That was working much better, but we still would occasionally get some oil in the exhaust/intake. We've since re-designed part of the oil return system and didn't see any signs of oil in either the exhaust or intake all week-end, and that was with the restrictor removed. I think this one is solved.
All of the electrical systems worked perfectly. The A/F guage shows the motor as a little lean down low, and progressively richer as boost comes on. Some quick adjustments with fuel pressure moved things in the right direction, but will probably require a little jetting as well. For now running fat is just fine with me. I have two LED's on the pod, one showing that the fuel pump is running, and the other hooked to a pressure switch that gets its air from the Fuel Pressure Regulator's boost line. When the motor sees 4LBS boost, the light comes on. If I see boost on the guage but no light to go with it, something bad is about to happen. I didn't like the idea of possibly smoking a motor because of a kinked hose or 20 cent clamp not doing it's job, and this seems like cheap insurance...
We took it fairly easy this week-end, starting boost off at 3 pounds then slowly adjusting it up to 6-7. Even with a poor clutch setup, the sled will walk up to 120 MPH indicated without effort. No question that with proper clutching and suspension set-up, the sled will see well in excess of 130 MPH on the speedo.
Overall, I would say the weekend was a success. Clutching this thing is going to be interesting, but I have a few ideas on where to start. The intercooler blew off once after coming off throttle, and the POV needs a quick tweak, but otherwise everything worked out really well.
