Out with the old...in with the new...Britain's Racecar Development, Subaru Engine, Lotus Suspension! Time to go racing! Options

[grantsfo]

Best thing you could do for a 914 is put a real suspension from lotus on the thing!

Can you legally put rear suspension on the 914 in XP?

I think the Boxster had a "slight" handling edge over your car on the West course. (IMG:style_emoticons/default/beerchug.gif)

2100 lb Boxster getting done on West course with 200 HP.

http://www.youtube.com/watch?v=6bSamEj-9CA

Well maybe East course too.

http://www.youtube.com/watch?v=DJ0r1g2HgOM

FYI we were running 315 rears and 285 fronts. A6's rule!

This post has been edited by grantsfo: Sep 12 2011, 03:28 PM

[Britain Smith]

Slight handling edge is an understatement...I had horrible understeer that I couldn't dial out. In addition, when I got back to Portland I determined that I didn't have full throttle either. Even with my 40year old suspension I shouldn't have been that far back behind the Boxster.

-Britain

[grantsfo]

Slight handling edge is an understatement...I had horrible understeer that I couldn't dial out. In addition, when I got back to Portland I determined that I didn't have full throttle either. Even with my 40year old suspension I shouldn't have been that far back behind the Boxster.

-Britain

Lol! You seemed to have "throttle issues" at San Diego when the boxster cleared you by couple seconds too. A lot more development has gone into that Boxster since you ran against it at National Tour. We got 10 more hp by fixing headers and by intalling more free flow exhuast, sorted suspension with full mono balls and better GT3 rear arms and while it was only 60 lbs lighter than when you saw it in San Diego it has far more weight up front. Over 100 lb change in front weight bias. I spent many weekends after getting it back from Brad pulling more weight off back so we could put radiators back up front. Based on few straights in video your car was getting to speed fine. As you know West course wasnt about power but holding speed. Your corner entry speeds were much slower then both me and my co-driver. We were carrying more consistent speed in slaloms as well. And the gearing with 18s was Eriks plan that paid off big.

Look at Tobys Times against Zust in 2010 NT in his FP BMW when he ran XP. He cleared your FP car by even more than his co driver and Evan in the Boxster.

http://www.scca.com/documents/resultfiles/results16.pdf

Zust only beat him by second and a half. Boxster beat Toby the new FP national champion on the West course this year. Don't underestimate the car it is very quick. I can assure you Boxster put appropriate distance on you. You will see once you get real suspension under you. But then we were prepared and well rested for Nationals with a car that we froze development on months before nationals. We had weekly calls etc to get it set. Had all spares we needed too and then Chose the right driver to get job done. Fast guy with mid engine driving experience. We didn't show up to Nationals to sort the Boxster.

Once you get real suspension under the "914" you should be able to keep up with the Boxster. You are on the right track but have to say you are doing exactly what I said would have to be done to make a 914 nationally competitive. I didn't have time or resources to spend several years developing a full on XP 914 build like this one. With suspension mods your likely 2 years out from being ready now. Boxster was quick and simple path to a national level car in FP. Very capable car right out of the box. Erik who drives a national level SSM car says Boxster out handles his Mazda. And Boxster has abs. You have abs plans too? We did lots of work on brake balance this year. Car was amazing under braking. Especially that fast sweeper. I was under driving the car.

Good luck with the lotus suspension. This should be very interesting!

This post has been edited by grantsfo: Sep 12 2011, 10:10 PM

[Britain Smith]

What do you want me to say Grant...I have explain the amount of issues that I had so comparing times is not relevant. I rolled the dice and made a change before Nationals and I ended up paying for it. You are correct, I had slow corner entry speed...the car pushed so badly that it was the only way to get it to turn. However, you are not correct about the throttle issue. I didn't know exactly what was wrong so I had turned the boost up almost all the way to get that kind of speed. After fixing the throttle for this past weekend's event I had those kinds of speeds at the lowest boost setting possible, the difference was night and day. I can now light up the rear tires easily, something that I couldn't do at Nationals. I will continue the development of the car and try again next year.

-Britain

[Britain Smith]

Ok...this winters project has official begun. It was very difficult to make the first cut, but after four 12-15hr days we finally have a Lotus double a-arm front suspension mounted in a 914. In the spirit of the SCCA X-Prepared rules, I wanted to integrate the assembly into the unibody the best that we could without completely tubing the front of the car.

I began by mocking up the Lotus suspension assembly in the Lotus front sub-frame.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a8.sphotos.ak.fbcdn.net-364-1319269899.1.jpg)

Then I secured the hub and built a quick jig to locate the chassis pick-up points to translate to the 914 chassis.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a6.sphotos.ak.fbcdn.net-364-1319269900.2.jpg)

This is the completed front jig.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a3.sphotos.ak.fbcdn.net-364-1319269900.3.jpg)

Start of rear suspension mock-up. The lower front mount is actually part of the Lotus chassis and not part of the rear sub-frame assembly so I had locate it separately for the jig to be properly built.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a5.sphotos.ak.fbcdn.net-364-1319269900.4.jpg)

Driver side rear mock-up.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a6.sphotos.ak.fbcdn.net-364-1319269901.5.jpg)

Driver side rear jig in place.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a4.sphotos.ak.fbcdn.net-364-1319269901.6.jpg)

Driver-side front and rear jigs completed. I passed a solid rod through the lower pick-up points and it is interesting that the arm length of both front and rear are the same.

(IMG:http://www.914world.com/bbs2/uploads_offsite/hphotos-sjc1.fbcdn.net-364-1319269901.7.jpg)

[Britain Smith]

With the jigs completed, it was time to remove the stock Porsche suspension. It is amazing how much time and effort one can put into the stock set-up and still not overcome the compromises. (Full Rollerbearings, raised spindles, Elephant tie-rod droplinks, S-calipers, Carrera rotors, Wevo strut tower mounts, seam welded control arms, bump-steer rack spacers, etc. etc.)

(IMG:http://www.914world.com/bbs2/uploads_offsite/a2.sphotos.ak.fbcdn.net-364-1319270479.1.jpg)

With the stock stuff out of the way, it was time to put the Lotus jig in place.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a3.sphotos.ak.fbcdn.net-364-1319270480.2.jpg)

Now....skip ahead 4 days of gruel work...and you get this...

(IMG:http://www.914world.com/bbs2/uploads_offsite/a4.sphotos.ak.fbcdn.net-364-1319270480.3.jpg)

Like I said previously, we did out best to integrate into the stock unibody of the 914 chassis in the spirit of the SCCA rules. Additional support will be added once the shock mounts are completed and the cage is tied in.

Here is the stock Lotus rotor/wheel mounted and suspension set on middle adjustment hole with lower a-arm parallel to the ground.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a6.sphotos.ak.fbcdn.net-364-1319270480.4.jpg)

Side shot:

(IMG:http://www.914world.com/bbs2/uploads_offsite/a3.sphotos.ak.fbcdn.net-364-1319270481.5.jpg)

Inside look of the control arms and the lower subframe. One of the days I will strip all the undercoating and make it look all pretty.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a8.sphotos.ak.fbcdn.net-364-1319270481.6.jpg)

Placement of the steering rack. Adjustment built in to allow for changes in both the control arm height and bump-steer. Again, additional bracing will be added to the mounts as the steering rack takes a lot of force.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a5.sphotos.ak.fbcdn.net-364-1319270481.7.jpg)

Placement ideas for the front shocks. No, I won't be running two shocks...the outer shock will be replaced by an adjustable push rod and a rocker assembly will be designed and installed in this approximate arrangement.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a1.sphotos.ak.fbcdn.net-364-1319270482.8.jpg)

[Britain Smith]

I have a few additional parts to design and make before completely finishing the front assembly. I will then move on to the rear as I believe that it will be a bit more challenging. With both ends completed, I will cut out the existing cage and built a new one that ties everything together.

-Britain

BTW...all the suspension parts from the car will be sold if anyone is interested.

[DBCooper]

I'm interested in the suspension. I'll PM.

And again, wow. Wow. Wow.

[maf914]

Great work, Britain. Since you are no longer using the 914 inner fender strut mounts will you be cuting away sheet metal for weight savings?

Adding Lotus components to your Porsche 914 chassis made me think of some historical precedents. In the 60's George Follmer attached a Lotus 23 chassis to his Porsche 2.0L and proceeded to win the USRRC championship. Also I want to say that Porsche bought wheels and suspension components from Lotus for some of their early 550 Spyder-type racing cars, but I am not sure of the details, something I read, long ago. These little bits of random information keep swirling around in my head....

[Britain Smith]

Great work, Britain. Since you are no longer using the 914 inner fender strut mounts will you be cuting away sheet metal for weight savings?

Adding Lotus components to your Porsche 914 chassis made me think of some historical precedents. In the 60's George Follmer attached a Lotus 23 chassis to his Porsche 2.0L and proceeded to win the USRRC championship. Also I want to say that Porsche bought wheels and suspension components from Lotus for some of their early 550 Spyder-type racing cars, but I am not sure of the details, something I read, long ago. These little bits of random information keep swirling around in my head....

I am actually using the inner fender for part of the support of the subframe so I am not sure how much more I will remove. I need to be in the spirit of the XP rules so I don't want to go overboard with tubes everywhere. The material in those fenders is pretty thick and structural so I will take advantage of that.

Regarding the Lotus suspension on early Porsche racecars, I was specifically walking around the paddock at Rennsport Reunion last week taking pictures of early Porsches suspension designs.

-Britain

[Randal]

I have a few additional parts to design and make before completely finishing the front assembly. I will then move on to the rear as I believe that it will be a bit more challenging. With both ends completed, I will cut out the existing cage and built a new one that ties everything together.

-Britain

BTW...all the suspension parts from the car will be sold if anyone is interested.

Looking good Britain.

Man what a job, unbelievable amount of work.

So the attachment points of that weight reduced subframe are on the body sheet metal (where you can see them in the picture) and where else?

[Britain Smith]

There are metal plates for the rear crossbar into the frame rails. I will be adding addition plates from the front subframe to the inner fender panels. In addition, there will be tubes from the a-pillar bars of the cage to the front cross member. From that I will add tubing to pick up the upper control arm mounts.

[campbellcj]

That is just amazing. When you mentioned this project up at Rennsport, I was having trouble visualizing...pictures tell the story nicely.

[Andyrew]

VERY Nice!

[Dave_Darling]

In the 60's George Follmer attached a Lotus 23 chassis to his Porsche 2.0L and proceeded to win the USRRC championship. Also I want to say that Porsche bought wheels and suspension components from Lotus for some of their early 550 Spyder-type racing cars...

There was at least one Lotus-Porsche. There were also a number of Elva-Porsches (three or four were at the Quail last weekend), and of course the famous "Poopers".

The Lotus uprights and brakes were used on the 904s, I think.

--DD

[campbellcj]

There was at least one Lotus-Porsche. There were also a number of Elva-Porsches (three or four were at the Quail last weekend), and of course the famous "Poopers".

The Lotus uprights and brakes were used on the 904s, I think.

--DD

This is apparently a Lotus 19 with a modified body and a 911 engine. It ran at Rennsport IV.

(IMG:http://www.914world.com/bbs2/uploads_offsite/farm7.static.flickr.com-21-1319342263.1.jpg)
Porsche-powered Lotus (?) by cjcam, on Flickr

[JRust]

What do we call it now? The ShitsubyusBox (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/biggrin.gif)

It is looking great Brit! Excellent work as usual (IMG:style_emoticons/default/beer.gif)

[J P Stein]

I like it, I like it.......

[Hontec]

Very, very nice!!!!! good choice the Lotus parts, very strong and light!

take a look at these; even kinky-er!!

front racing hubs

rear racing hubs

racing wishbones


you're not done pimpin"

(IMG:style_emoticons/default/biggrin.gif)

PS: use the S2 wheelbearings with ABS rings/sensor incorporated and use a racelogic traction control.....you will be truly amazed......

[Brett W]

So why did we pick the Lotus suspension instead of running a 928 front spindle with custom a-arms and a multilink 996/997 setup in the rear? It would all be Porsche stuff. You built the subframe, so building it using Porsche parts would have been easy.