You can barely see it in the pics above, but the sides of the grill were trimmed to allow the grill to be pulled through the front body work of the car without interference. The two bumps on either side, under the grill will also be trimmed flush with the bottom surface of the grill to prevent contact with the front bumper when the grill is swung out through the front.
Discussion of Chassis Setup for 8 Sec. Assault
- Thread starter Alky V6
- Start date
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I'm going to build a support structure out of small square tubing and rivet it to the backside of the block off panel to give it support. I'm still figuring out the basic layout for the framework. All the mounting point loads will be handled by the radiator support. The block off plate will be transferring any load directly to the mounting structure. The plastic grill will basically just be sitting in front to the block off plate.
You can see at the top of the block off plate that it overlaps inside the top of the grill mounting points. The three holes will be slid onto three angled pilot stubs. The stubs will be mounted on a framework that will be supported by the top framework of the radiator support. The pilot stubs will be angled such that when the air pressure is pushing on the grill, the grill will be forced up and back tighter onto the stubs. When the grill needs to be removed, the bottom of the grill will be swung out first, pivoting on the angled pilot stubs until the bottom of the grill is clear of the bumper, then the top of the grill is simply pulled down off the pilot stubs at the top. At least, this is the plan at this point. As things progress, I may find that I will need to change something to make it work better. You know how that goes.
Another option may be to unfasten the grill at the bottom, drop the grill off the pilot stubs, then swing the top of the grill out first, followed by the bottom part of the grill. That makes the bottom mounting structure more interesting.
I thought you guys may find this site to be useful to this thread
http://www.racetec.cc/shope/
http://www.racetec.cc/shope/
Some pictures of the progress on the blocking of the front grill. I still need to fab the framework that will support the lower section of the grill and carry the load to the radiator support. I also need to angle the air filter a little different.
Attachments
Which file are you referring too? The full suspension file?
I did some testing this weekend. A complete disaster. The car has never been so loose.
The main thing that must be worked out before I can properly evaluate the chassis is the boost controller pressure curve and the nitrous system shut off timing. With the larger nitrous shot, the boost rise is now steeper and I'm having to radically adjust the boost controller pressure curve to get the boost tamed down. By the very last run of the weekend I found a control pressure that finally seemed to nose the boost rise over for the 1-2 shift. The point where the boost nosed over was still too high, but at least it did nose over. It's just a matter of lowering that point now.
This weekend was the first time that the car blew the tires away after the 2-3 shift. I don't know what that's about. After I get the boost control squared away, I should have a better idea.
Max boost level over the weekend was 295 kPa.
I lowered the rear tire pressure from a 10 3/4 hot to 10 1/2 hot, to 10 1/4 hot. Measured after returning to the pits. The car seemed to be more stable with the lower pressure when the car did break traction.
The main thing that must be worked out before I can properly evaluate the chassis is the boost controller pressure curve and the nitrous system shut off timing. With the larger nitrous shot, the boost rise is now steeper and I'm having to radically adjust the boost controller pressure curve to get the boost tamed down. By the very last run of the weekend I found a control pressure that finally seemed to nose the boost rise over for the 1-2 shift. The point where the boost nosed over was still too high, but at least it did nose over. It's just a matter of lowering that point now.
This weekend was the first time that the car blew the tires away after the 2-3 shift. I don't know what that's about. After I get the boost control squared away, I should have a better idea.
Max boost level over the weekend was 295 kPa.
I lowered the rear tire pressure from a 10 3/4 hot to 10 1/2 hot, to 10 1/4 hot. Measured after returning to the pits. The car seemed to be more stable with the lower pressure when the car did break traction.
I'll get them to you.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
- Messages
- 5,802
The height isn't any higher than it's always been for years. I'm just curious if the traction will come back. Have to try things to find out. Besides, too much tire rubbing with the car being lowered.A lift kit for a drag carLower the car Don before you hurt yourself.
I lost you guys way in the begining with all the numbers.But from experience. If you try too many things at once you will get lost. Trust me that's where I'm at. Right now I'm heading back to basics. To me that is putting all my weight back over the rear axle and loosening up the front all the way. I will dial it back from there.
Second I agree on blocking off the front grille. You did a great job on that Don. My car at 167 felt like it had very little steering control. I've had an aluminum form made for the back of the grille for years, just never followed through.I will be completing that soon. I also believe that the solid front airdam helps. I will try and re pro a similar airdam that is lower by at least 1.5 inches.
Second I agree on blocking off the front grille. You did a great job on that Don. My car at 167 felt like it had very little steering control. I've had an aluminum form made for the back of the grille for years, just never followed through.I will be completing that soon. I also believe that the solid front airdam helps. I will try and re pro a similar airdam that is lower by at least 1.5 inches.
One major difference I noticed right away with the blocked off grill. I have to make a bee line to the pits and get her shut down. The engine temp gets hot much quicker and higher. I don't have a radiator fan, and got away with it as long as some kind of airflow was going through the radiator. I may have to add a fan now.
This last weekend netted some great new numbers for the car.
5.80@126.2 mph, 1.37 60'. The car was a dream to drive.
I can officially state that the car is at least back to the same performance level I was getting with the smaller turbo, with the mph being much better. There is still some tune left to throw at her.
The key adjustments to getting the car over the hump was dialing in the boost controller and playing around with the rear tire pressure. It wasn't any more sexy than that. The shock, sway bar, alignment, and spring settings have been unchanged since the last major suspension upgrade work.
The boost controller is leveling the boost at 200-210 kPa (14-15 psi) for the 1-2 shift and the max boost level for the rest of the pass for this last test & tune was 290 kPa (27-28 psi). Still a couple more pounds to throw at her, and with the performance increases I've been getting from just a .5 psi increase in boost, I don't think the car will handle it. We'll give it try anyway. :biggrin:
The tire pressure turned out to be very important. As was suggested by some, I started out by raising the rear tire pressure to 10.75 from 9.75 I had been using for quite some time. The results were disasterous, if not downright dangerous. I had a very big problem getting the car to hook throughout the whole pass.
I then lowered the tire pressure to 9.25 and immediately noticed a big difference in tire slippage, stability and mph. I then dropped to 9.0 psi and finally 8.75 is where it's at now.
A video of a latest pass with the car. YouTube - Spooling a 91mm Turbo
5.80@126.2 mph, 1.37 60'. The car was a dream to drive.
I can officially state that the car is at least back to the same performance level I was getting with the smaller turbo, with the mph being much better. There is still some tune left to throw at her.
The key adjustments to getting the car over the hump was dialing in the boost controller and playing around with the rear tire pressure. It wasn't any more sexy than that. The shock, sway bar, alignment, and spring settings have been unchanged since the last major suspension upgrade work.
The boost controller is leveling the boost at 200-210 kPa (14-15 psi) for the 1-2 shift and the max boost level for the rest of the pass for this last test & tune was 290 kPa (27-28 psi). Still a couple more pounds to throw at her, and with the performance increases I've been getting from just a .5 psi increase in boost, I don't think the car will handle it. We'll give it try anyway. :biggrin:
The tire pressure turned out to be very important. As was suggested by some, I started out by raising the rear tire pressure to 10.75 from 9.75 I had been using for quite some time. The results were disasterous, if not downright dangerous. I had a very big problem getting the car to hook throughout the whole pass.
I then lowered the tire pressure to 9.25 and immediately noticed a big difference in tire slippage, stability and mph. I then dropped to 9.0 psi and finally 8.75 is where it's at now.
A video of a latest pass with the car. YouTube - Spooling a 91mm Turbo
