<VIDEO> RADIUM Elise Turbo Kit at Thunderhill, California

[Radium]

http://www.youtube.com/watch?v=ryQEy_2vOnE

We had the great pleasure to spend a day at Thunderhill Raceway Park with the Golden Gate Lotus Club. We drove 9 hours from Portland, OR to Willows, CA with our prototype turbocharged Lotus Elise in tow. The goal of the trip was to test our products at elevated temperatures and at racing driving conditions.

We participated in six 20 minute sessions throughout the day, for a total of 2 hours of high-speed driving. We were running our Stage 2 GT2860RS turbocharger kit that was making 300Hp at the wheels. We are also using the stock engine, transmission, and clutch. Ambient temperatures for the day topped 100 degrees F and this definitely had an effect on the vehicle. The car was not babied either. Shifting was always done at or near 8,500 RPM, and the engine spent most of the track above 5,000 RPM. The added low-end torque of the turbocharger did help to pull the car out of the occasional botched turn without the need to downshift. The stock radiator was working hard, but successfully held the coolant temp at no hotter than 205F. Intake air temperatures did climb, but ignition timing was automatically reduced to account for the hotter air. This reduces power, but also keeps the engine safe by preventing knock. Even in these extreme conditions, driveability of the car remained perfect. The power delivery was instantaneous, but always smooth and very controllable. The GT2860 is definitely a very good match for the Toyota 1.8L.

At the mid day lunch break, we removed the rear clamshell for a full inspection. Heat is a constant menace to the engine bay and we have been experimenting with different solutions. First off, we added a duct that directs fresh air from the driver-side intake vent directly to the underside of the intercooler, where an electric fan then forces it through the intercooler and out the rear deck lid. We also created an air dam to prevent hot air from the turbocharger from entering the suction zone of the electric intercooler fan. These solutions seemed to work very well, as the intercooler was not becoming heat soaked and consistently cooled the charge air by about 30 to 40 degrees. We were also experimenting with ceramic coatings. Out exhaust manifold, turbocharger, and downpipe were all treated with a thermal barrier coating designed to reduce the radiated heat. We made improvements to our stainless steel exhaust manifold heat shields and were testing those as well.

During the mid-day inspection, we were pleased to see no physical damage from the heat. All components were intact and functioning just fine. But just because nothing broke, doesnt mean that we aren't going to make any improvements. We are currently exploring other heat management devices that can control the heat even more than what we have already. Keeping the heat trapped in the exhaust system not only lowers under-hood temps, but also improves spool-up of the turbocharger.

At the end of the day, I did get the pleasure to ride shotgun with a much more experienced driver in his '05 Elise. Robert S. had no mercy on his vehicle and was able to push it around the track at an unbelievable rate. We look forward to the day when we let an experienced driver like Robert track our turbocharged Elise and push it to its full potential.

Thank you to the Golden Gate Lotus Club for holding the event and running it in a relaxed and open format. And thank you for the opportunity to mix it with you guys out there. It was a fun day, and we look forward to doing it again.

[robin]

Hi,

Interesting write up (though perhaps nobody else from Scottish Elises was there ).

20 minutes at a time is probably not going to allow heat soak to reach its maximum, assuming you're back in the pits for 40 minutes afterwards?

I know that some of us often drive the cars for up to an hour at a time on circuit and in (for us) hot ambients up to around 40C (which is more or less 100F). My Exige S certainly suffered in those conditions both in terms of the amount of power it produced and also the air cooling available to the engine.

Assuming you're making more power than the supercharged versions most of the time, have you done anything to beef up the oil and/or water cooling?

I've seen people use air-water intercoolers with front mounted radiator too - any thoughts on those?

Cheers,
Robin

[Radium]

Robin-Thanks for the reply!

20 minutes at a time is probably not going to allow heat soak to reach its maximum, assuming you're back in the pits for 40 minutes afterwards?

Actually, right at 15minutes in each session is where I am noticing the intake air temperatures begin to slow down and flatten out in the data logs.

I know that some of us often drive the cars for up to an hour at a time on circuit and in (for us) hot ambients up to around 40C (which is more or less 100F). My Exige S certainly suffered in those conditions both in terms of the amount of power it produced and also the air cooling available to the engine.

Ditto! With the top off in the Elise, you can feel the 200F (93C) radiant heat coming off the front heat exchanger over the windshield. You can feel the car reacting to the elevated temperatures for sure. I have the ECU programmed to retard ignition timing proportionally with air temperature to keep the engine safe.

Assuming you're making more power than the supercharged versions most of the time, have you done anything to beef up the oil and/or water cooling?

So far we have not monitored oil temperature, only oil pressure. Water temperature, even on this day, was surprisingly quite normal. We never saw above 215F (102C).

I've seen people use air-water intercoolers with front mounted radiator too - any thoughts on those?

Absolutely. That was actually our first concept. But we wanted to test a lighter, cheaper solution first to see where we are at. With the proper ducting we have recently added and the fan we are using, an air to air intercooler is a viable alternative.

The main problem stems from the manifold and turbocharger heat. We believe we have solved this though with this heat shield constructed from multiple layers consisting of metal foil, ceramic fiber, and silica fabric, custom fit for our application and sewn together with Inconel thread.

http://www.radiumauto.com/blog-new-products.php

When we enter the Stage 3 territory, however, we will be experimenting with an air to water intercooler.

[tut]

Good to see this sort of feedback from someone who is a real enthusiast in upgrading our Elises/Exiges and has turned it into a business.

As you have seen from Robin, there is a wealth of knowledge and enthusiasm on here, we also pride ourselves of dicking most of the rest of the UK and Europe on track, especially in the rain and snow, we do live in Scotland.

Unfortunately we will not get the chance to join you on track, I have an Elise S1 with a S/C Honda engine installed, so at 750kg, we would not be too far out on a bhp/wt ratio.

Cheers

tut

[andyc]

Tut said: Unfortunately we will not get the chance to join you on track

Speak for yourself....I'll probably be in San Francisco nearer the end of next year.....might take a run up there
Same kind of distance from my mates house as it is from mine to Knockhill!!

[Radium]

I'll probably be in San Francisco nearer the end of next year.....might take a run up there

Andy-If you have time, you are welcome to meet up with us in Portland. Maybe Northwest Lotus Club will be holding there last P.I.R. trackday meet of the year while you are here.

Portland International Raceway does not have the elevation changes like Thunderhill, but is still very fun. Here is a video of us running the turbocharged Stage 2 "Sport Kit" Elise around the P.I.R...

http://vimeo.com/15573136

-Radium Engineering

[Scotty C]

looks like a nice piece of kit and a couple of very nice tracks to. shame you didn't show a complete lap so we can get a better idea of how it runs.

Nice slicks as well