I'm bringing this thread back from the dead because I can't find adequate information on this setup and I'm not a member of the Supra forums so I cannot see the linked thread. I've been googling and searching these boards to find more answers and information about compound turbocharging and imparticular the Boost Logic kit that's being sold now for only $7k albeit you still need an IC & piping, plus a hundred other micellaneous items not to mention fuel. As I understand it, it delivers significant gains over twins or singles in both fields of low-end torque and high-end horsepower. I've only seen one one set of dyno numbers comparing the compound setup to a large single and it was impressive making in some cases two and three times the amount of power and torque at a given RPM.

Power delivery is very important to me. For this reason I've always considered twins for their inherent benefits with lag. But a traditional twin setup has been proven to not be of a huge benefit with the power delivery and in the end you are sacraficing somewhat especially with the size constraints of the SC engine bay compared to the Supra. However, having a smaller turbo coupled with a larger one may fit in the engine bay better and act almost as a sequential setup giving you gobs of torque at the low revs and then allowing the larger turbo to do it's thing and produce huge horsepower for the highway runs against the likes of Corvettes and Supras...sounds awesome to me. Anybody have any input?

 

^^^^ I like BL's compound kit setup but I rode in a Supra (GT4580) with the SP Spool Valve setup and I must say I was pretty impressed.

Info Here--> http://www.spracingonline.com/projec...ve/3643”

 

It looks very clever and an ingenious design. But my worry with that is the timing and the reliability. That crossover point I think would take some time to hone in and what if it sticks. Now your $1500 turbo is giving you half the puff it should. Nonetheless a very cool gadget.

 

Oh yeah, and there is an SC that has the Boost Logic kit and he's putting down ~750WHP @ 25psi...not bad.

 

whats the difference between a "compound" setup and a "sequential setup" as on the stock 2JGTE's ? Sounds like the same concept just bigger turbos....

 

The basic difference is that with the compound turbocharging you're taking the entire exhaust displacement and feeding it to only one turbo. The exhaust gases that pass thru the first turbo then are routed to the second larger turbo which gets the larger turbo going. Once the smaller turbo reaches it's desired boost level of...say 20lbs there is a type of wastegate that is positioned before the first turbo. That "wastegate" then re-routes excess exhaust gas around the first smaller turbo and into the second larger turbo for the big kick on the top end. So, you now have the small turbo pumping everything it can and the large turbo pumping everything it has as well. Thereby, giving you initial torque and horsepower of a smaller turbo and the huge top end power of a massive turbo, without the lag.

A sequential setup, feeds full exhaust gas to both turbos simultaneously. Then thru a series of vacuums, solenoids and other actuating devices gives you very good throttle response and torque as well as good top end power for a very linear powerband. But it's a very complex setup and most prefer to do away with the headaches of sequentials when pursuing a big horsepower figure.

With the compound turbo setup it's like having two cars in one. Imagine if you could have a 450 WHP streetable car with say a GT28 AND a 800 WHP highway rocket with a GT42 simultaneously!! That is essentially what this technology does for you. According to one owner I saw on a YouTube vid, you can even hear the car spool up two seperate times which is kinda weird but cool.

I'm dying to see a dyno from one of these cars but I haven't seen any yet. Anyone a member on the Supra boards? Maybe there are some there??

*NOTE* My knowledge of sequential turbocharging is limited to say the least but I think my statement is just about correct.

 

http://www.youtube.com/v/y-Me6yWApzY..._embedded&fs=1

Here is the link to the YouTube vid I saw...

 

I have seen this in action. You can actually hear it spool twice. Pretty cool

 

Hey guys is BL still the only company making one of these kits? Now that is has been around for a while what are people's thoughts on them?