 Out with the old...in with the new...Britain's Racecar Development, Subaru Engine, Lotus Suspension! Time to go racing! |
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| Britain Smith |
 Jun 2 2011, 01:16 PM
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#281
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Nano Member  Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364  |
Sorry for the lack of updates guys, been really busy with work and spending time with the family. Got some time this last week to get some items in order.
At the last event up in Packwood, I dealt with fuel starvation and fuel temperature issues. Basically, about the 4th or 5th run in the car (with 2 drivers), I would get fuel starvation issues going thru sweepers and long corners. I would bring the car back into the Pits and top off the fuel tank. While the fuel level was not really low, I would fill it up anyway. After doing this, I observed fuel coming out of the vent tube on the tank. There is a check valve in the tank, however it was fluttering up and down and letting fuel thru. I determined that this was a result of high fuel temperature (E85) that was pressurizing the tank once the cap was installed. I was unable to continue running that afternoon and have made some changes to the fuel system that I will test this coming weekend. In this older image, you can see the position of the fuel pump. I had it mounted about 3" higher than the bottom of the tank and farther forward...meaning the fuel had to go uphill and forward while the car was accelerating. I guess I was under the assumption that these pump had more suction that they really do. (IMG:http://www.914world.com/bbs2/uploads_offsite/a7.sphotos.ak.fbcdn.net-364-1307042188.1.jpg) In either case, I have now relocated the pump inside the passenger compartment and level with the bottom of the fuel tank. The fuel line now snakes by the steering rack and thru the front bulkhead. (IMG:http://www.914world.com/bbs2/uploads_offsite/a2.sphotos.ak.fbcdn.net-364-1307042188.2.jpg) (IMG:http://www.914world.com/bbs2/uploads_offsite/a6.sphotos.ak.fbcdn.net-364-1307042189.3.jpg) This configuration will also have the added benefit of keeping the fuel pump cooler and it is not exposed to the heat coming off the radiator. Further tests and observations will be completed at the upcoming events. I also tried my hand at some sheetmetal work to complete the radiator shroud between the front bumper and the radiator itself. It is really nice when you have access to a shear, brake, and one of those air powered nibblers. It is really hard to take a good picture of this, but it is all sealed up and you get the general idea. (IMG:http://www.914world.com/bbs2/uploads_offsite/a4.sphotos.ak.fbcdn.net-364-1307042189.4.jpg) And finally, got the car corner balanced and aligned. I was surprised to see some of my alignment specs out from where I expected them to be, but I got the car where I want them. The corner weights came out perfect and I have a solid 45/55% weight distribution. -Britain |
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| Britain Smith |
Jun 14 2011, 05:42 PM
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#282
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Despite the work I had done to the fuel system, I continued to have fuel starvation issues. I believe that the combination of fuel slosh and a high flow fuel pump combined to emptying out the sump in the fuel tank quicker than the fuel could return....therefore causing air to be sucked into the system. Therefore, I set about to redesign the fuel system with a much better set-up.
The first thing I did was mock up the approximate size of the JAX Pro Stock fuel tank (8x8x15") in cardboard to determine if I could get it to fit in the stock fuel tank location. (IMG:http://www.914world.com/bbs2/uploads_offsite/a1.sphotos.ak.fbcdn.net-364-1308094979.1.jpg) When I called JAZ to discuss the tank, I was able to order it in the exactly specifications that I needed. I went with a high flow AN-10 fitting at the bottom to feed the fuel pump, an AN-6 return line fitting, and an AN-8 vent line fitting. This is the beginning of the new fuel tank install. I got the tank in "natural" finish so I can monitor the fuel level without having to look down inside. (IMG:http://www.914world.com/bbs2/uploads_offsite/a4.sphotos.ak.fbcdn.net-364-1308094979.2.jpg) Here is the tank completely installed. Worked perfectly all the way down to the level of the fuel in this picture. The engine felt so much more responsive and never bogged down...success! (IMG:http://www.914world.com/bbs2/uploads_offsite/a2.sphotos.ak.fbcdn.net-364-1308094979.3.jpg) Placing the tank in the stock location not only allowed an elevative position in relation to the fuel pump, it also allow me to fab up a new firewall to separate the radiator heat from the fuel system. (IMG:http://www.914world.com/bbs2/uploads_offsite/a8.sphotos.ak.fbcdn.net-364-1308094979.4.jpg) After running the car through 16 runs at the last AX event, the firewall was VERY hot to the touch and the fuel tank was only moderately warm. I am very happy with the results and now I can return my focus on driving. -Britain |
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| DBCooper |
Jun 14 2011, 05:52 PM
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#283
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14's in the 13's with ATTITUDE Group: Members Posts: 3,079 Joined: 25-August 04 From: Dazed and Confused Member No.: 2,618 Region Association: Northern California |
QUOTE(Britain Smith @ Jun 14 2011, 03:42 PM)  I am very happy with the results and now I can return my focus on driving. -Britain With all he radical changes you made to that car if it only took you that long to sort things out it means you've done an exceptional job. Congrats. Be proud, that's VERY well done and we're all envious. |
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| Britain Smith |
Jun 14 2011, 05:58 PM
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#284
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Many Thanks.
It was actually quite frustrating that of all the changes made to the car, I was fighting the fuel tank. Car is ready to go for the WCR in Medford in two weeks. I also bought a new truck to tow my trailer more efficiently on long hauls...can't wait to make the trip. (IMG:http://www.914world.com/bbs2/uploads_offsite/a4.sphotos.ak.fbcdn.net-364-1308095931.1.jpg) -Britain |
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| Chris Pincetich |
Jun 14 2011, 08:39 PM
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#285
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B-) Group: Members Posts: 2,082 Joined: 3-October 05 From: Point Reyes Station, CA Member No.: 4,907 Region Association: Northern California |
QUOTE(Britain Smith @ Jun 14 2011, 04:42 PM) After running the car through 16 runs at the last AX event, the firewall was VERY hot to the touch and the fuel tank was only moderately warm. I am very happy with the results and now I can return my focus on driving. -Britain How did it go? Did you win? (IMG:style_emoticons/default/biggrin.gif) |
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| Britain Smith |
Jun 16 2011, 03:15 PM
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#286
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Here is a video from the last event taken with a friend's Go-Pro. I need to pull the video from my camera to compare. I will be the first to admit that my driving is a little behind after spending all my time sorting the car, but now that the car is working well I can focus on having fun again.
The sound of the engine is awesome, gotta love the Suby spinning to 8200rpm. Enjoy... http://www.youtube.com/watch?v=u8DUqVoMGMk...utu.be&hd=1 -Britain |
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| PeeGreen 914 |
Jun 16 2011, 03:23 PM
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#287
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Just when you think you're done...wait, there is more..lol Group: Members Posts: 10,219 Joined: 21-September 06 From: Seattle, WA... actually Everett Member No.: 6,884 Region Association: Pacific Northwest 
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Looks and sounds great (IMG:style_emoticons/default/aktion035.gif)
Awesome venue (IMG:style_emoticons/default/dry.gif) |
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| Britain Smith |
Jun 16 2011, 03:26 PM
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#288
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Yea...venue sucks. The car is actually a bit to stiff now for that crappy place. I can't wait to stretch its legs down in Medford and then Packwood on the same weekend. Let the fun begin!
-Britain |
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| Britain Smith |
Jun 16 2011, 08:52 PM
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#289
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Here is in-car video from the same run. Little different perspective...just as much!
http://www.youtube.com/watch?v=iNdMq03Zwg8...eature=youtu.be -Britain |
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| jzdu |
Jun 16 2011, 09:55 PM
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#290
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Member Group: Members Posts: 69 Joined: 7-July 08 From: Medford, Or Member No.: 9,268 Region Association: Pacific Northwest |
Looking forward to seeing you run down here
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| Britain Smith |
Jul 25 2011, 11:25 PM
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#291
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Well, it has been a while since I have updated this thread.
Two weekends ago was the Packwood National Tour, me and my co-driver took 1st and 2nd in a field of 14 drivers. While it was nice to finish out on top, we struggled in the car all weekend due to lack of rear grip and changing weather conditions. Here are the video's of my fastest runs. Saturday: http://www.youtube.com/watch?v=L4yHNRq6cbI Sunday: http://www.youtube.com/watch?v=u0lQXPahUvw With the new engine set-up, as more power is dialed in with the boost controller all the shortcoming in the suspension start being amplified. To date I have already corded two sets of rear tires and I have pretty much destroyed a third set after running the Tour and the ProSolo event this past weekend. To dial out the understeer on the car, I went about stiffening up the rear suspension from 275lb to 325lb rear springs. With that change I had difficulty putting the power down and the rear of the car became very tail happy both on and off the throttle. Adjustments to the front sway-bar did very little to help. During the ProSolo this past weekend I decided to revert back to the 275lb rear springs and that made a world of difference in getting the power down and settling the rear end. In fact, it was so dramatic that I red-lighted three runs in a row despite leaving the tree at the same time as I did on previous runs. I won't say that it cured the oversteer, but it helped. Here is a video of the ProSolo fun: http://www.youtube.com/watch?v=cp4KiVPQSr8 -Britain |
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| Britain Smith |
Jul 25 2011, 11:33 PM
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#292
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Now it is preparation time for Nationals. Due to the struggles that I have had with the current tire set-up...I have seen the light and now realize that it is time to try something different and go big!
Therefore, with the 3 free tires that I won thru contingency with Hoosier, I am going to switch from Bias Ply to Radials. I should be able to get at least 2degs of negative camber dial in, hopefully a bit more. I have also decided to increase the mechanical grip in the rear from 10" to 12" wide tires. This will require me to do a little "modification" to the rear fenders...but as they say, Go Big or Go Home! I should get the tires in the next week and I will post pictures when I receive them. -Britain |
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| Britain Smith |
Jul 25 2011, 11:50 PM
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#293
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
So, this brings me to the topic of my next project. I want to ditch the '70 era suspension design and move into the 21st century.
Here is my problem. Front Suspension: Current set-up is McPherson strut design which gives ~2.5" of scrub with 8" wide wheels. You are also limited in available, acceptable, shock designs. Rear Suspension: Semi-Trailing arm which is making it difficult to get the power on the ground. My plan is to move to a double wishbone, multi-link suspension set-up both front and rear. With that in mind, I have made some measurements and decided to basically transplant a Lotus Elise/Extige suspension onto my chassis. I will optimize the positioning of the attachment point for my ride height and basically copy the good hard work from Lotus for the rest of the placement. The best part is that the available shock choices are infinite...I have seen sets of Öhlins for around $1000 to $1500. Here is a good view of both the front and rear set-ups. Front: (IMG:http://www.914world.com/bbs2/uploads_offsite/www.sandsmuseum.com-364-1311659424.1.jpg) Rear: (IMG:http://www.914world.com/bbs2/uploads_offsite/www.sandsmuseum.com-364-1311659427.2.jpg) I am currently working on locating the necessary parts, so the ball is already rolling. I will post pictures as I go. If you know anyone that might have Lotus suspension parts, please let me know. -Britain |
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| cantgo2fast |
Jul 26 2011, 01:33 AM
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#294
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Newbie Group: Members Posts: 9 Joined: 11-July 11 From: Fort Collins CO Member No.: 13,299 Region Association: Rocky Mountains |
Wow this is a fantastic build just read the whole thing tonight. I hope to be going down this road by next year sometime. I will definitely be hitting you up for those wiring diagrams. I just cant justify running an ej207 and not utilizing the avcs.
Not to throw another project on you but have you ever thought about doing an electric shift system. I realize its only two gears but it would allow you to keep your hands on the wheel. Secondly, what is with that rear wing? A class restriction? it looks like its just a wall. If you want to know where to get a really nice carbon dual element wing with real engineering and CFD numbers behind it let me know. Great build either way and looks like a blast. Im hoping to come out to nationals this year with our race car (Colorado state FSAE). We retrofitted an aero package and gained about 30 hp (IMG:style_emoticons/default/shades.gif) so hopefully we can be more competitive. |
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| Britain Smith |
Jul 26 2011, 10:19 AM
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#295
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
Yea, I would love to get more information on a rear wing from you. The spoiler is left over from the days that I ran E-mod.
I look forward to meeting you at Nationals. -Britain |
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| andys |
Jul 26 2011, 01:20 PM
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#296
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Advanced Member Group: Members Posts: 2,165 Joined: 21-May 03 From: Valencia, CA Member No.: 721 Region Association: None
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Britain,
Have you perhaps considered grafting in a suspension from a Boxster. This reasoning is based on a couple of factors: 1.) parts are plentiful and sure to be lower cost than the Lotus parts, 2.) lots of mature race development with spec Boxster racing; they are a very good handling car. I'm a roadrace guy, so I know nothing really about AutoX, but there should be enough similarities. Just a thought. Andy1 |
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| Chris Pincetich |
Jul 26 2011, 01:54 PM
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#297
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B-) Group: Members Posts: 2,082 Joined: 3-October 05 From: Point Reyes Station, CA Member No.: 4,907 Region Association: Northern California |
photos!!
Great job so far, and good luck getting it sorted for the BIG SHOW (IMG:style_emoticons/default/beerchug.gif) |
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| cantgo2fast |
Jul 26 2011, 02:02 PM
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#298
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Newbie Group: Members Posts: 9 Joined: 11-July 11 From: Fort Collins CO Member No.: 13,299 Region Association: Rocky Mountains |
Heres the write up on the wing development. It's definitely tailored to road racing but it has real engineering behind it and is sure to work. Good read too, not too complex.
APR dual element wing It will undoubtedly be a while before production but it might be ready for next season. |
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| Britain Smith |
Jul 26 2011, 02:37 PM
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#299
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
QUOTE(andys @ Jul 26 2011, 12:20 PM) Britain, Have you perhaps considered grafting in a suspension from a Boxster. This reasoning is based on a couple of factors: 1.) parts are plentiful and sure to be lower cost than the Lotus parts, 2.) lots of mature race development with spec Boxster racing; they are a very good handling car. I'm a roadrace guy, so I know nothing really about AutoX, but there should be enough similarities. Just a thought. Andy1 Hey Andy. The Boxster suspension was evaluated, however it is built for a heavier car and still uses strut design which is what I want to get away from. I think you would be surprised how cheap the Lotus parts cost. -Britain |
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| Britain Smith |
Jul 26 2011, 02:40 PM
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#300
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Nano Member Group: Members Posts: 2,354 Joined: 27-February 03 From: Hillsboro, OR Member No.: 364 |
QUOTE(cantgo2fast @ Jul 26 2011, 01:02 PM) Heres the write up on the wing development. It's definitely tailored to road racing but it has real engineering behind it and is sure to work. Good read too, not too complex. APR dual element wing It will undoubtedly be a while before production but it might be ready for next season. Very interesting article...we will be in touch. I have address the power, now I am working on suspension, and finally I will optimize aero. -Britain |
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