Main British Car:
1969 MGB Buick 2.0
Mark Sawatsky's Turbo 4 powered MGB-Part 5
Posted by: loosecannon
Date: July 11, 2016 12:22PM
Briget and I competed in another local event that took place on a road course with some fast sweepers and good acceleration zones. The balance of the car was great, as was the acceleration and braking, however neither of us were getting the lap times we needed to do well in PAX. My best time was good enough for Fastest Time of Day but was about 4 seconds too slow for a PAX win. I may have not been driving like an alien but I felt that my times should have been better. I looked at the data when I got home and my peak lateral load was only 1.05 G so it's clear that my 4 year old Avon tires are done, done, done. I had the diffuser on for this event and the car was noticeably more stable at high speed so that's all the incentive I need to move forward with aero development. Check out what a pylon hitting Alumalite at 70 mph looks like:
Video of one run here: [www.youtube.com]
I finally switched to the beautiful Keizer aluminum wheels
Video here: [youtu.be]
I hate the spoilers used in EMod because they don't look good on anything but it's all we are allowed and having one will make me quicker so I built one. It's the same Alumalite I used for the splitter, riveted together. I will be changing its color to mask it a little bit.
Video here: [youtu.be]
I had my first event today with the Keizer wheels, Hoosier tires and spoiler and I don't know how much each of those things contributed to my performance but I think I was 2-3 seconds quicker than before based on my times relative to my competitors. Despite the extra grip of the tires, it was much easier to spin them and I'm not sure if it's because the rotating mass is so much lower or because fixing all the boost leaks has resulted in a bunch more power. The braking was also much more confidence inspiring and I didn't hear or feel any lockups but I did smell something when I hit the brakes hard for one of the hairpin turns so maybe a tire was locked up. Because of the extra grip, the car now leans a lot more so I stiffened the front sway bar one notch and raised rear roll centre. I had my best PAX result yet (10th) and had Fastest Time of Day by nearly 4 seconds but it wasn't all rainbows and unicorns, the right rear tire and wheel rubbed on the Panhard mount so I need to make some changes to the rear track width.
Video of quickest clean run: [youtu.be]
After the event I did a post-race inspection, a habit I picked up from karting, and discovered some clearance issues with the new wheels and tires. The right rear tire and wheel had enough deflection to touch the Panhard bar under hard cornering. I couldn't use any more wheel spacers so watch the video and see how I got some more clearance
During the last event, the extra grip of the Hoosiers caused the car to lean a lot more and scrape the splitter in turns. For todays event I raised the front half an inch and made some changes to the sway bar and roll center and the car felt amazing. The end plates of the spoiler were also changed and now are at the 100 square inch maximum. I didn't change a thing through all 4 regular competition runs and had my best PAX finish of 5th. I watched Briget wiggle the car through the course and it appears to rotate around the rear wheels, which is also what Jeff Keisel's Sprite appears to do so maybe I'm on the right track? I meant to try the car on a fun run without the rear spoiler on just to see what the difference was but instead I messed around with roll center. So, the car has 97 autocross runs, 7 road course laps and 3 passes down a drag strip with the worst thing happening being a tire rubbing on a Panhard Bar.
Video of a couple of runs: [youtu.be]
I was out of adjustment on the axle side of the Panhard bar so I decided to take the opportunity to make the whole mechanism better. The axle side and the frame side were simplified and lightened and I took 10 lbs off the car, much of it unsprung weight.
Video Here: [youtu.be]
Today I had my first chance to try the changes I made. For my first run I was very aggressive with throttle and steering and the car would get sideways in one part of the course and would understeer in another part. Initially, I thought I needed to stiffen front sway bar but on my next run I realized that my driving was a bigger problem. I landed up raising rear roll center a bunch then driving it like a tail happy car I.E. Brake sooner and accelerate through the turn. This worked well and I set Fastest Time of Day and 9th in PAX. The course had great average speed and was very much about speed maintenance, there was very little acceleration or braking except at pivots. I have a ton of work to do before Nationals because the combination of settings is almost infinite.
Video here: [youtu.be]
I went over the engine data logs from the last event and they confirm what I felt was happening. On my first run, I had the gas pedal 100% down for 2.71 seconds where on my quickest run, I had the pedal down for only 0.6 seconds. This week I have had the car in the garage and have been checking everything over in preparation for Nationals. I also changed the anti-squat settings in the rear suspension, installed a switch that only allows the car to be started when clutch is depressed and stiffened the Panhard bar frame mount. If you look at the rear suspension in that last video I posted, you will see that the 2" square tubing Panhard mount flexes as I pitch the car into a turn. I welded a 2" x 1/4" flat bar to the mount so that shouldn't happen again. I blocked off all the openings in the front of the car because they aren't needed for cooling or anything but I made the panels easy to remove if I need more air for the intake.
It was a double header weekend and on Saturday the course was cone intensive and basically a long slalom where speed maintenance was king. For the first couple of runs I had the suspension way too stiff so I pulled the pins on the rocker arms and moved them over to soften the wheel rate. This worked wonders and made the car quite driveable and I landed up with FTD and 10th in PAX. On Sunday the course was fast and wide open with a couple of spots where the course tightened up and you could really hang yourself. Well, I did hang myself and for some strange reason, when braking from high speed the rear wheels would lock up and throw me into a spin. This is only speculation, I can't be sure, but I think it's because I have blocked off the openings in the front end. Maybe it has reduced lift and threw off the balance? I changed the balance and went on to get FTD and 10th in PAX again. Looking at the video of my runs, I left a lot of time on the table-perhaps 2 or 3 seconds just from not trusting the brakes. Check out the video of the spin.
I have lots to tell, so buckle up. We arrived in Lincoln on Sunday morning and immediately got out on the test course. The pre-Nats stiffening of the suspension made the car oversteer, spin the inside rear tire and lock up the rear tire under braking. I would make a change then run again but couldn't get the balance right. If I softened the rear suspension, the spinning tire problem would improve but the understeer problem increased. The same thing would happen if I lowered the rear roll center. I tried various combinations of front and rear roll centers, sway bar settings and even changed caster and anti-squat. The test course workers knew us very well after two days of testing. They say the test course times are meaningless but we couldn't help but look at our competitors times and make comparisons. It looked like we were sort of in the ballpark of the other EM drivers except for Shawn and Jeff Kiesel-they were far ahead of us.
By Monday evening, we had the car feeling the best that it had been. It was still slightly understeery and if we drove smoothly, the rear tire spin was minimal. Jerry from Bad News Racing contacted me and asked how things were going and I mentioned that it would helpful if boost came up quicker. He showed me what to adjust and warned me that if I went too far, the car would start to buck violently. On Tuesday morning, first day of competition, I made the change to the tune and was doing a checkover of the car. It was then that I noticed a big difference in how much rear suspension droop there was from the left side to the right side. The car was sitting perfectly level but the right rear drooped 3 inches and the left rear drooped 1.5 inches. After some thought, I realized that the 80 lb weight difference between left and right side of the car could be the source of my handling problems. At the time I scaled the car, I didn't think much of us because the car used to have a passenger seat and my lap times weren't too affected by having a 200 lb passenger. I borrowed 65 lbs of lead from Del Long and placed it in the drivers seat and got Briget to sit on it. Sure enough, once the car was re-adjusted to be level, I had a bunch more droop on the left rear suspension. Nothing more could be done because we had to work then run the East Course.
Briget pulled up to the line, not having a clue how the car would feel because we never had a chance to test it with the lead attached. She came back reporting that the car felt much better and the boost came up quicker, too. I went on my run and was too conservative but the car did feel pretty good. I made another quick change to the tune to bring the boost up quicker and went a little harder on my next run and got into some marbles but still ran 3/10 second quicker. I changed the tune again and drove harder on my 3rd run and lopped a second off but tipped over the last cone on the course. I was not happy with my lousy driving but the car felt pretty good. We went back to the paddock and I took the lead and bolted behind the rear axle and just above the diffuser. This increased the left rear droop by another half an inch.
On Wednesday morning, I took the car out on the test track and with stone cold tires on a cool 8:00 am track, I matched my best previous lap time. The car felt amazing and I hopped out and let Briget have a go. She came back pretty excited about the handling, too. I increased the rate that boost comes up and went out again. The turbo lag improved and I changed it again. If I was going to go too far with it, I wanted it to be on the test course. I kept increasing it and now the turbo was making a loud whistling that I hadn't heard before. Then it started to rain and I got to see how predictable the car is in slippery conditions. I was very surprised how hard I could push and not lose control, the car was quite good. The braking problem seemed to be cleared up, too. A couple of hours later, it was time to race the West Course.
Briget had been comparing herself to one of the other drivers in the class and on day 1, their times were almost identical. With the changes we made, she was now 3 full seconds quicker! I went out for my first run and overshot two turns pretty badly, getting into the marbles and losing a ton of time. I was still only 1.6 seconds slower than Jeff Kiesel and was pretty confident I could get a lot closer on my following runs. On my next run, I corrected the mistakes from my previous run but made all new ones, getting off the racing line and into the marbles. I changed the boost control again and was now way beyond what Jerry has been able to do on a stock Buick Regal without running into problems with bucking. The boost came up quick and strong with no problems at all but I drove far too conservative and was unable to improve my time. Clearly, the car is much more capable than I am and I need to learn how to drive the beast. Attached is a video of a run from each course and I'll be sharing more videos in the next few days.
Some updates on what I'm doing with the car, the picture is a clue
Video here: [www.youtube.com]
With all local autocross events over and some engine tuning still to be done, I went to the last drag race event of the season. The tech inspector warned me that if I went quicker than 11.5 seconds in the 1/4 mile, I would have to wear a neck collar and wrist restraints. I fully expected to go quicker than that because I car of my weight and horsepower should, with proper chassis tuning, be able to do 10.3 seconds at 134 mph. I knew I would never do that because I don't have the suspension or tires to launch that hard and my car maxes out at 119 mph. but it should still be really quick. I did a little burnout and pulled up to the line. The lights came down and I launched in 2nd gear, the tires just lit up and were spinning all the way through 2nd gear. I shifted to 3rd and they tires got traction briefly then spun almost all the way to redline. I was doing nearly 80 mph by this point and when the tires finally caught and the boost came up, the car pulled pretty hard to the end of the 1/4. My time was a pathetic 12.0 seconds but my datalogger indicates that I lost over a second to wheelspin. I drove back down the return road and the officials stopped me and told me that I had dropped gravel for 50 feet down the strip. I noticed that mine were the only tires that picked up rocks and I stopped in the staging lanes and cleaned them off but as soon as I moved forward, they picked up fresh gravel again. My day was over and I didn't learn anything except that my little Ecotec makes pretty good power and that the car is rock solid at 119 mph.
Video here: [youtu.be]
I finally started on the off season modifications and here's a quick video showing what I'm up to: [youtu.be]
I am way overdue for an update on the car so here is a video of what has been going on: [www.youtube.com]
Recap: At Nationals, the higher grip levels revealed a problem with lifting the inside rear tire and locking up the rear tires. I determined that this was due to the left rear tire having 90 lbs less weight on it than the right rear. To correct it, I moved the battery, fuel cell, surge tank and overflow tank to the left rear side and also moved the intercooler and radiator. Here is a shot of the scales before I did all that:
And now after I have made the moves
As you can see, there was significant improvement in rear weight bias, left/right balance and overall weight. I now have 54.3% weight over the back tires and almost 50/50 left/right balance. This should make the car accelerate, turn and stop better.
Since I no longer have the giant twin fans on the radiator, I have room for a better diffuser. The old one didn't have the right shape for low speed stuff but the new one should be much better. I will be painting it but for now you can see it in it's unpainted form. Here's the video on how I made it: [youtu.be]
When I purchased my transmission, I thought the 82 mph in 3rd gear would be perfect for Nationals because most people agree that we hit 80 mph on the courses. However, I found out pretty quickly that 1st was a little low so we would start off in 2nd and use 2nd and 3rd only. There is a 30 mph spread between 2nd and 3rd and it would take a moment for the power to come up again. Also, several times on course, the car would either be redline in 2nd or lugging in 3rd. I looked at other available gears available for the Super T10 and found one that will work much better. It has a useful 1st gear that is good for 45 mph and a 23 mph spread to 2nd gear and another 21 mph spread to 3rd gear. This should result in better acceleration and more choices of gears on track. It was way cheaper to buy a new gearset than a new transmission so that's what I did. Attached are pictures from a speed calculator for the old gearset (3.42 first gear) and new (2.64 first gear) plus a picture of the actual gears.
Update: My transmission has been sent off to a shop to get the new gears put in and I have hired Kyle from the Kyle Drives YouTube page to help me with the aerodynamics of the car. He is currently modelling the Pink Panther in 3D CAD so he can do a Computational Fluid Dynamics test on it. We Skyped for a while and he has looked over pictures and video of the car and has already given me some suggestions on what to do. Everything he has suggested is easy to do but he is going to do a CFD run before and after the changes to see how big the benefits are. He liked what he saw so far and I'm happy I have not made any big mistakes with the aero. Here is his YouTube page, and he is as friendly as he seems in the videos: [www.youtube.com]
Made a new cowl out of aluminum, video is attached
Here's an update on the car. I had a 30 minute Skype call with Kyle from the Kyle Drives YouTube page. He is an aerodynamics expert from Australia and he gave me some advice on my car. He 3D modeled the car and did some CFD testing on it. It currently makes 100 lbs downforce but most of that is at the back. I remade the cowl and engine cover out of aluminum and they are now really smooth and I'm proud of the panel gaps and how they look. I remade the splitter as well but have just been informed that it doesn't quite follow the rules so some changes will be made there. Kyle is in England, working with a Formula 1 team so I'll have to wait until he gets back to do another CFD run on my car. I also have the new gears in the transmission and they should be ideal for acceleration. Enjoy the pictures.
This picture shows the turbulent air (dark blue) coming off the front tires, having no easy exit.
So, I gave the bad air a place to go
And got to use my Cleco kit for the first time (it's awesome)
Some cutting, bending, grinding, trimming, priming and painting later
I made a video of the whole build, from V12 to V8 and now with 4 cylinder power. If you don't want to spend 8 hours reading a build thread, just watch this
Edited 21 time(s). Last edit at 03/13/2017 09:48AM by loosecannon.