As many of you know, Ryan and I over here at Cool Tech have been big advocates of Jason's TT kit for the GT. We have installed several of them now and, perhaps more importantly, we have continued to service the cars that we have done the conversion on. This has allowed us the unique opportunity to monitor durability and owner feedback. Every owner who has made the conversion remains "giddy" with their set-up. It is almost like religion! Various circumstances have permitted us to spend a LOT of dyno time on the cars and we can notice both similarities and differences between the unique cars, despite that we are using the same kit.
At our last dyno day here in Socal - with a large forum member turn-out, many people got to witness first hand what it feels/sound like when a clutch starts to let go. This is what we experienced with Apollo (Terry's) car. Unfortunately, it was the end of the dyno day for Terry and time to order a new clutch. Truth be known, to make the access to the transaxle a lot easier, a lot of the turbo installation needed to be removed. Remember the Six Million Dollar Man series? "We can re-build her. We can make him better than he was."
Over the last 12 months or so we had been working with Jason and his team on some new ideas for the system. We KNEW that the changes that we wanted to make would likely give us better long-term reliability and less under-clamshell heat and we further suspected that they could very well yield some performance benefits to boot! Jason was on-board for us to give the mods a try as he was interested to incorporate any positive changes into a "Version 2" of the Heffner TT Kit.
Well, I'd say that the improvements surpassed all of our best expectations. First, under-clamshell heat was significantly reduced which was one of our primay objectives. This offers protection for the TT components, but also all of the under-hood components. The changes are also a little more OEM-like and I think they will also have greater duability/longevity than the components they replace. So, this was the "cake", what about the icing?
When discussion performance for a forced induction car - the common discussion theme is "area under the curve". Anytime you can get even modest improvements in area under the curve, the car is going to perform better. Superchargers are typically great at "area under the curve" as boost (and power) come on almost instantly. But, the trade-off in the SC applications is in top end perfromance where the turbos are king. So, the best solution might be a TT, where you retain the high-end performance and you find ways to get the turbos spun up sooner and bring the power on at a lower RPM. That's exactly what we accomplished.
Take a look at the graphs below. This is Apollo's car before and after our changes. Keep in mind that Terry's car was NEVER slow and, in fact, it was always within spitting distance of the top performing TT and TT+SC GTs at the mile venues. This Blue line on the graph is the BEST dyno run we ever did with Terry's car - right after we first did his TT conversion a year ago.
The red line is after the changes we made. The performance differences were pretty darn spectacular. I want to emphasize:
1. Same Car (Apollo's)
2. Had already proven to be among the fastest TT's
3. Same Dyno
4. SAME tune (Heffner TT 100 Octane tune)
5. Max Boost Approx. the same (The pre-mod boost actually higher)
Note: We added a Boost-a-pump to this car and subsequently tuned it with Torrie to exploit the BAP.... but these graphs were made with the same tune so we could have the most honest comparison possible to the previous results.
Please have a look at the attached graphs.....


At our last dyno day here in Socal - with a large forum member turn-out, many people got to witness first hand what it feels/sound like when a clutch starts to let go. This is what we experienced with Apollo (Terry's) car. Unfortunately, it was the end of the dyno day for Terry and time to order a new clutch. Truth be known, to make the access to the transaxle a lot easier, a lot of the turbo installation needed to be removed. Remember the Six Million Dollar Man series? "We can re-build her. We can make him better than he was."
Over the last 12 months or so we had been working with Jason and his team on some new ideas for the system. We KNEW that the changes that we wanted to make would likely give us better long-term reliability and less under-clamshell heat and we further suspected that they could very well yield some performance benefits to boot! Jason was on-board for us to give the mods a try as he was interested to incorporate any positive changes into a "Version 2" of the Heffner TT Kit.
Well, I'd say that the improvements surpassed all of our best expectations. First, under-clamshell heat was significantly reduced which was one of our primay objectives. This offers protection for the TT components, but also all of the under-hood components. The changes are also a little more OEM-like and I think they will also have greater duability/longevity than the components they replace. So, this was the "cake", what about the icing?
When discussion performance for a forced induction car - the common discussion theme is "area under the curve". Anytime you can get even modest improvements in area under the curve, the car is going to perform better. Superchargers are typically great at "area under the curve" as boost (and power) come on almost instantly. But, the trade-off in the SC applications is in top end perfromance where the turbos are king. So, the best solution might be a TT, where you retain the high-end performance and you find ways to get the turbos spun up sooner and bring the power on at a lower RPM. That's exactly what we accomplished.
Take a look at the graphs below. This is Apollo's car before and after our changes. Keep in mind that Terry's car was NEVER slow and, in fact, it was always within spitting distance of the top performing TT and TT+SC GTs at the mile venues. This Blue line on the graph is the BEST dyno run we ever did with Terry's car - right after we first did his TT conversion a year ago.
The red line is after the changes we made. The performance differences were pretty darn spectacular. I want to emphasize:
1. Same Car (Apollo's)
2. Had already proven to be among the fastest TT's
3. Same Dyno
4. SAME tune (Heffner TT 100 Octane tune)
5. Max Boost Approx. the same (The pre-mod boost actually higher)
Note: We added a Boost-a-pump to this car and subsequently tuned it with Torrie to exploit the BAP.... but these graphs were made with the same tune so we could have the most honest comparison possible to the previous results.
Please have a look at the attached graphs.....

