Several members have been by to checkout my car, I think at least a couple have placed an order. Those that have been by know that I was planning on running BBORR, so thought I would share the results...
FYI, my car has a stock LS-7 and V10 Graz.
For those of you not familiar with Open Road Racing; It is on public roads, closed to the public. Classes are timed (winner closest to correct time for their speed), except the Unlimited Class which is what you would expect. Each class has a 'tech' speed, which you cannot exceed (radar on course so you will get DQ'd and put on the not welcome list). It takes years to work your way up to Unlimited, and rightly so. We don't need some yahoo getting himself killed and ruining things for everyone. You can choose to run with/without a navigator/co-driver (you can split driving if you would like). Most choose to run with a navigator. Big Bend is probably the most challenging of the bunch in the USA because the Sanderson end of the course is windy and hilly. So while top speeds tend to be 210-215 for unlimited cars, the winning speed is usually 170s. More info for Big Bend at www.bborr.org
While I can't call my car 'finished', I did have it on track in February, and ran BBORR a couple of weeks ago.
While out at MSR Crescent, I did identify several issues. They boiled down primarily to:
- Bad voltage regulator (too much voltage)
- Needing MUCH stronger springs front and back
- Needing downforce on the rear
To get ready for Big Bend, we replaced alternator, battery (fried), headlights (fried), installed the rear wing, front fender vents, moved to 850f/900r springs and trimmed the fenders to better clear the tires.
Car passed tech with no issues - the factory 4 point cage is good for Grand Sport (168 tech speed). Past that, the car will need a full cage with a steel inner roof. As a purpose built car, we needed a full fire system to run Grand Sport (but a Corvette does not, go figure).
For practice, officials close off a short (9-10 miles) section of a different highway for short periods of time and let a limited number of cars run down and back before re-opening the road and letting traffic through. At Big Bend, the practice course is reasonably challenging and seems to eat one car a year from the higher classes.
In practice the car felt much better than it had on track. Could have used a bit more caster, but tracked reasonably well and the additional downforce had it planted in the corners and stopped the tires from spinning in the upper gears. Ran it up to about 6800rpm in 6th. Still needs stiffer springs, but now that is probably because of the downforce. We have the front lift so had to move to 2.25" springs, but now we have a good selection available. If you want to move to the smaller diameter springs, PM me and I will share what I learned.
We did have some motor issues and struggled for days to get to the bottom of them. Finally did about midnight before the race. Turned out the fuel pump circuit breakers were toast. The original high voltage could have caused the issues, or engine compartment heat, or ???. But they are toast. Ended up re-wiring around them. For anyone interested, these are the breakers supplied with Summit brand kits and are rated at 30 amps. We have 3 pumps (one tank to surge and two pressure), all the circuit breakers fell apart when removed.
On race day, we had some clutch slippage which we had never seen before and had to baby it up to 6000rpm in 6th. Was 10 miles in cruising at 6000rpm when the motor lost a bit of power and then grenaded. Smoke and fire followed immediately but the fire was out by the time we got the car stopped. When the motor let go the cabin filled with smoke, which surprised me. We were running w/o side windows, but do have the bulkhead and the side 'tunnels' well sealed. Thankfully we were on a straight, so it was just a matter of holding it straight until the yellow line re-appeared.
We coasted to a gate marshal, so had shade, food and water while watching the rest of the cars go by. The officials said it was pretty spectacular, but no video.
The engine is a GM Performance LS-7 with no mods (other than flipping the intake). Since it took quite a while to get the car done, I've had it for a while. But first started the engine about 6 months ago. I am going to see what GM says about it. There is a whole in the block near cylinders 3/5 just at the oil pan. Oil pressure, water temp and MIL were all good when it let go. Had a few hundred miles on it and I don't think it had ever hit the rev-limiter.
In any case, I will have to do something about the Graz gearing as RPMs are through the roof unnecessarily. While the low 1st is OK for the parking lot, it is useless otherwise. I find I only really need 3rd and 6th gears for normal driving. For spirited driving 2-3-4-6 are the appropriate shifts. Still contemplating what to do about this.
Car is still in the trailer. I managed to crumble a piston in our Lotus this week so I feel obligated to help my son fix it. The SLC will probably sit for a couple of weeks before I tear into it.
FYI, my car has a stock LS-7 and V10 Graz.
For those of you not familiar with Open Road Racing; It is on public roads, closed to the public. Classes are timed (winner closest to correct time for their speed), except the Unlimited Class which is what you would expect. Each class has a 'tech' speed, which you cannot exceed (radar on course so you will get DQ'd and put on the not welcome list). It takes years to work your way up to Unlimited, and rightly so. We don't need some yahoo getting himself killed and ruining things for everyone. You can choose to run with/without a navigator/co-driver (you can split driving if you would like). Most choose to run with a navigator. Big Bend is probably the most challenging of the bunch in the USA because the Sanderson end of the course is windy and hilly. So while top speeds tend to be 210-215 for unlimited cars, the winning speed is usually 170s. More info for Big Bend at www.bborr.org
While I can't call my car 'finished', I did have it on track in February, and ran BBORR a couple of weeks ago.
While out at MSR Crescent, I did identify several issues. They boiled down primarily to:
- Bad voltage regulator (too much voltage)
- Needing MUCH stronger springs front and back
- Needing downforce on the rear
To get ready for Big Bend, we replaced alternator, battery (fried), headlights (fried), installed the rear wing, front fender vents, moved to 850f/900r springs and trimmed the fenders to better clear the tires.
Car passed tech with no issues - the factory 4 point cage is good for Grand Sport (168 tech speed). Past that, the car will need a full cage with a steel inner roof. As a purpose built car, we needed a full fire system to run Grand Sport (but a Corvette does not, go figure).
For practice, officials close off a short (9-10 miles) section of a different highway for short periods of time and let a limited number of cars run down and back before re-opening the road and letting traffic through. At Big Bend, the practice course is reasonably challenging and seems to eat one car a year from the higher classes.
In practice the car felt much better than it had on track. Could have used a bit more caster, but tracked reasonably well and the additional downforce had it planted in the corners and stopped the tires from spinning in the upper gears. Ran it up to about 6800rpm in 6th. Still needs stiffer springs, but now that is probably because of the downforce. We have the front lift so had to move to 2.25" springs, but now we have a good selection available. If you want to move to the smaller diameter springs, PM me and I will share what I learned.
We did have some motor issues and struggled for days to get to the bottom of them. Finally did about midnight before the race. Turned out the fuel pump circuit breakers were toast. The original high voltage could have caused the issues, or engine compartment heat, or ???. But they are toast. Ended up re-wiring around them. For anyone interested, these are the breakers supplied with Summit brand kits and are rated at 30 amps. We have 3 pumps (one tank to surge and two pressure), all the circuit breakers fell apart when removed.
On race day, we had some clutch slippage which we had never seen before and had to baby it up to 6000rpm in 6th. Was 10 miles in cruising at 6000rpm when the motor lost a bit of power and then grenaded. Smoke and fire followed immediately but the fire was out by the time we got the car stopped. When the motor let go the cabin filled with smoke, which surprised me. We were running w/o side windows, but do have the bulkhead and the side 'tunnels' well sealed. Thankfully we were on a straight, so it was just a matter of holding it straight until the yellow line re-appeared.
We coasted to a gate marshal, so had shade, food and water while watching the rest of the cars go by. The officials said it was pretty spectacular, but no video.
The engine is a GM Performance LS-7 with no mods (other than flipping the intake). Since it took quite a while to get the car done, I've had it for a while. But first started the engine about 6 months ago. I am going to see what GM says about it. There is a whole in the block near cylinders 3/5 just at the oil pan. Oil pressure, water temp and MIL were all good when it let go. Had a few hundred miles on it and I don't think it had ever hit the rev-limiter.
In any case, I will have to do something about the Graz gearing as RPMs are through the roof unnecessarily. While the low 1st is OK for the parking lot, it is useless otherwise. I find I only really need 3rd and 6th gears for normal driving. For spirited driving 2-3-4-6 are the appropriate shifts. Still contemplating what to do about this.
Car is still in the trailer. I managed to crumble a piston in our Lotus this week so I feel obligated to help my son fix it. The SLC will probably sit for a couple of weeks before I tear into it.