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

[DBCooper]

Like a light switch, huh? I told you you were going to have to re-learn some things to go fast in a turbo car. Ask Alain Prost. Funny thing is you didn't SEEM like a crazy man, but from this thread it's obvious you are. And that JP guy, he's having almost as much fun egging you on as you're going to have aiming that thing and pulling the trigger. Cool. Very well done. I'm a fan.

[BMXerror]

...Funny thing is you didn't SEEM like a crazy man, but from this thread it's obvious you are...

It's the quiet ones you've gotta worry about. (IMG:style_emoticons/default/stirthepot.gif)
Well, how did it go today? The 'World is dying to know.
Mark D.

[Britain Smith]

Went well. Still dealing with boost controller issues and wheel slip on the dyno making it difficult to tune properly, but the car is now running on E85 and it the craziest thing I have ever driven at speed.

-Britain

[DanT]

details (IMG:style_emoticons/default/biggrin.gif)

[Downunderman]

You should keep a close eye on your fuel plumbing and fuel pumps using that stuff. The V8 Supercars use it down here because it's so "green", but they regularly replace lift pumps and high pressure pumps because the fuel destroys all the rubber bits and seals.

I was in NZ looking after as friend's historic car at the Bruce McLaren Festival last year, and the fuel supplier unfortunately supplied E25 instead of AvGas and didn't tell anyone. The fuel dissolved the foam in bladder tanks and everyone with Lucas injection had to replace every seal. The fuel even pissed out of one metering unit enough to set a car on fire. All manner of problems ensued. The litigation is ongoing.

We weren't so lucky, detonated Repco Brabham motor which required two new cylinder heads.

Cheers,

[Britain Smith]

Howard....thanks for that tip. I built the entire fuel system to be compatible with E85, but I didn't think about the foam inside the tank. I just called RCI where I got the foam that they indicated that it will break down and shouldn't be used with E85. Now I need to find a safety foam that is compatible...any suggestions?

-Britain

[messix]

Howard....thanks for that tip. I built the entire fuel system to be compatible with E85, but I didn't think about the foam inside the tank. I just called RCI where I got the foam that they indicated that it will break down and shouldn't be used with E85. Now I need to find a safety foam that is compatible...any suggestions?

-Britain

Check with a sprint car supply

[Downunderman]

I would try ATL. I'm off to Phillip Island this afternoon for the big historic meeting with the same car, it only took 15 months to have new heads cast, machined and installed.

[Downunderman]

Bugger, heads are porous. Now spectating.

[bfrymire]

Britain,

When is your first autocross? I am really curious about what this is going to be like. For instance, does the boost hit in the right place (If not linear, could be a real surprise when boost come on.)? Does it come strong out of the corner, and what is it like off throttle entering a corner.

I have always done NA for autocross, as the turbo guys had a handfull.

-- brett

[FourBlades]

Very educational build. (IMG:style_emoticons/default/smilie_pokal.gif)

Take off the spoiler, get a different tranny and you may have a Land Speed Record car...

John

[Britain Smith]

Few updates.

I was having some issues with the Vehicle Speed Sensor set-up. I did a sort of shotgun approach to addressing the issue. I converted from a solid state hall effect sensor with the magnets in the trigger wheel to a proximity sensor and a notched trigger wheel. I also installed an ignition relay for the rear fuse panel instead of running straight through the master switch. I believe that I was getting voltage spikes when starting the car which may have cause premature death of the sensor. Either way, the combination proved reliable and ran all weekend without issues.

Here is the new Vehicle Speed Sensor installed with trigger wheel that I had cut on on the waterjet.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a6.sphotos.ak.fbcdn.net-364-1302158117.1.jpg)

Clearance between the VSS and the trigger wheel. Spec is 1.5mm and because it is threaded, it is fully adjustable.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a8.sphotos.ak.fbcdn.net-364-1302158117.2.jpg)

Also installed a pair of Tilton master cylinders. Previous set-up was 22mm front/19mm rear and the pedal pressure was significantly too high. New set-up is 18mm front/16mm rear which is still a bit high, but much more manageable. I currently run 911S aluminum front calipers, but I plan to switch to boxster calipers in the future.

(IMG:http://www.914world.com/bbs2/uploads_offsite/a4.sphotos.ak.fbcdn.net-364-1302158117.3.jpg)

Ran the car this past weekend at a Test and Tune event in Eugene. Mixed weather conditions made set-up difficult, but we got some good shake down runs in without any major issues. Need some more time to get the brake bias correct and we had a slight issue with the hydraulic clutch, but I suspect it needs to be bled better.

Just in case there was any question...the car is much faster than it used to be.

I will get some video and pictures at the next event when I am not spending all my time working on the car.

-Britain

[cary]

Congrats on the progress.

[J P Stein]

Congrats on the progress.

Yeah, it'd be great if he could find a dry parking lot. (IMG:style_emoticons/default/biggrin.gif)
Ain't spring in the PNW great? I retired for ths shit?

[Walter]

Nice speed sensor solution Britain!
Most use the sensor on the front axle with a RWD car though; just be mindfull reading it when you've experienced some rear wheel slip ;-)

[Britain Smith]

Yes, but in this case the actually speed is relative as the ECU just needs to know that the car is moving in order for the active valve timing to engage.

-Britain

[DBCooper]

And... how's it all going?

[Britain Smith]

All is going well actually...thanks for asking. I guess it is time for an update.

I ran the car the weekend before last and although it was very fast, I still have a few items to get sorted out.

First of all, here are some cool pictures taken at the event:
(IMG:http://www.914world.com/bbs2/uploads_offsite/a7.sphotos.ak.fbcdn.net-364-1303861030.1.jpg)

This seems to be the never ending story when running a prepared/modified car...working underneath the car.
(IMG:http://www.914world.com/bbs2/uploads_offsite/a7.sphotos.ak.fbcdn.net-364-1303861031.2.jpg)

My co-driver clipping an apex cone:
(IMG:http://www.914world.com/bbs2/uploads_offsite/a6.sphotos.ak.fbcdn.net-364-1303861032.3.jpg)

Me in the same corner with a little bit of rear brake lock-up.
(IMG:http://www.914world.com/bbs2/uploads_offsite/a4.sphotos.ak.fbcdn.net-364-1303861033.4.jpg)

Also, here is a video of one of my runs.
http://www.youtube.com/watch?v=pFjPYWhQ1fE...eature=youtu.be

If you watch closely you can detect the two main issues while driving the car.

First, the car was making way too much power for the cold weather, old tires, and crappy asphalt surface. Just before this event I installed a separate boost gauge to monitor pressures and it was reading 14psi which is double what my low boost setting is supposed to be at. I have recently installed a Turbosmart e-boost electronic boost controller so I can tune the boost curves and accurately set the boost value based on the driver and surface conditions. I also replaced all the silicon boost lines with proper AN-4 fittings and line. I will be on the dyno at Cobb Tuning Surgeline next Thursday to dial it in.

Here is a picture of the new Turbosmart e-boost controller:
(IMG:http://www.914world.com/bbs2/uploads_offsite/a2.sphotos.ak.fbcdn.net-364-1303861034.5.jpg)

Here is a picture of the solenoid in the engine compartment:
(IMG:http://www.914world.com/bbs2/uploads_offsite/a6.sphotos.ak.fbcdn.net-364-1303861034.6.jpg)

The second issue I was experiencing was brake balance. At every hard braking area I had to keep the car in control to keep the rear in from coming around on me. You can actually see it at the end of the video where the back in whips around unexpectedly. It made the car virtually impossible to drive at 10/10ths. No matter what adjustments I made the pedal assembly, nothing seemed to dial in correctly or be consistent. Later analysis determined that even though it was delivered from Tilton pre-assembly without ANY instructions, the positioning of the two clevis on the balance bar were incorrect. This was resulting in variable brake bias depending on which was the bar was resting in relation to the pedal assembly.

Here is an older picture illustrating the incorrect position of the clevis's:
(IMG:http://www.914world.com/bbs2/uploads_offsite/a1.sphotos.ak.fbcdn.net-364-1303861036.7.jpg)

Here is how the position of the clevis's should be...tight up against the pedal to minimize the movement of the bearing:
(IMG:http://www.914world.com/bbs2/uploads_offsite/a8.sphotos.ak.fbcdn.net-364-1303861036.8.jpg)

The only other observation from the event was that the fuel tank was very hot to the touch due to the close proximity to the radiator. I am limited by the SCCA rules on what type of ducting is allowed behind the radiator, so for the time being I am working on constructing an aluminum air deflectors/air gap which will be covered in heat reflective foil. This should be sufficient to keep the fuel tank temperatures at acceptable levels. Another option if it become necessary would be to run an aluminum fuel line thru a coil in the icebox for the intercooler, but we shall see.

Here is the initial mock-ups of the air deflector:
(IMG:http://www.914world.com/bbs2/uploads_offsite/a7.sphotos.ak.fbcdn.net-364-1303861036.9.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/a1.sphotos.ak.fbcdn.net-364-1303861036.10.jpg)

More to come after this weekends event and further dyno tuning.
-Britain

[McMark]

I would bet that a simple jacket of foil lined 'bubble wrap' would keep the heat from penetrating. That bare aluminum is probably grabbing all the heat it can.

If you make the deflector, maybe use SS since it's much slower to absorb heat.

[Downunderman]

Perhaps the issue with the brake balance is that the smaller of the master cylinders should be on the front and the larger on the rear.

Cheers,