Last year we had great success with our prototype Stage 2 turbocharger kit. We validated many of our parts as well as found weaknesses which were rectified. Stage 2 was running a Garrett GT2860RS turbocharger and a prototype stand-alone engine management system (EMS). It made 310WHP on race gas and spooled extremely well. We did not release it for sale due to the fact that we planned to package it with our stand-alone EMS, which is currently still in development. With the EMS in the hands of our software & electronics engineer, we focused our attention towards our Stage 1 kit.
Stage 2 Prototype, as ran in 2010.
The Stage 1 turbocharger kit was originally conceived to produce great low end torque while staying cost effective. A small-frame Garrett T3 60-Trim turbocharger was selected for its quick spool, compact package, and affordable price. Since a full stand-alone EMS for this kit pushed the price point too high, the kit was designed around a sophisticated Radium piggyback computer to handle the engine control and allow for normal on-board-diagnostics to be retained while integrating with the factory Lotus computer.
We experimented running this setup without an intercooler to keep cost down and simplicity up. This would also aid in better throttle response and quicker turbocharger spooling. The first test drives of the vehicle with this configuration were very promising. The high compression 2ZZ-GE would spool the turbo immediately with the slightest accelerator input and it would reach maximum boost pressure very early in the RPM band. This gave the car enormous low-end torque and immediate power.
Prototype Stage 1, Non-intercooled
After initial street-tuning, we visited Portland Speed Industries to use their dynamometer and calculate results. We carefully data-logged charge temperatures and other vital engine parameters. As anticipated, boost pressure was instant, but intake air temperatures were climbing to 120degreesF over ambient. In addition, the turbo was running out of breath in the upper RPM range. We were pushing the small turbo too hard and were paying the price in increased air temperatures and reduced flow. With this unacceptable performance, we concluded that the T3 60-trim is not a suitable option and we are stepping up to a T3/T4 hybrid turbocharger.
Dyno testing at Portland Speed Industries
The T3/T4 hybrid turbocharger uses the same quick-spooling turbine of the T3, but a larger T4 compressor for more flow. Spool will be slightly affected, but we anticipate it will still be extremely responsive. The high compression 2ZZ-GE works very well for spooling up medium frame turbochargers. More airflow from the T4 compressor will also mean cooler charge temperatures and might make a non-intercooled configuration more realistic. Thorough testing will tell.
The dyno session also provided a great opportunity to test our new exhaust manifold heat shield. This was specifically made for our application and uses materials and technology found in many major motorsports branches as well as military and aerospace designs. Throughout the dyno testing, the outside surface of the shield never exceeded 290degreesF. This is a staggering improvement over our previous attempts at controlling heat and we plan to include these heat shields with every kit. More information on this heat shield can be found here.
We will be returning to the dyno soon with the T3/T4 hybrid turbocharger and will update with results and impressions.
Looking forward, we have decided to eliminate the "Stages" nomenclature and will have one turbocharger kit that can be configured to the consumer’s preferences. This configuration will include a choice of turbocharger, engine management system, and intercooler package. As we move toward production release, we will be incorporating all of this info and more on our website which will soon feature online shopping capabilities. We are anticipating our base Lotus Elise turbocharger kit will start well under $5,000 for the most basic configuration (T3/T4 turbocharger, non intercooled, no engine management) and go up from there depending on selected options. We will continue to include every component necessary for install for a fully engineered solution. This will consist of relocation brackets, fluid plumbing, hardware, exhaust, wiring harness adapters, etc. Performance expectations of each configuration will also be supplied in the form of dyno charts and related information.
Please stay tuned as we work toward final release with solid prices. We will supply as much information as we can on all aspects of the turbocharger kit as we address issues and move toward the final configurations. Contact us directly at firstname.lastname@example.org with questions.