got a idea to pass by everyone. tell me why it wouldn't work.

i had a t76 on my 408 and it spooled instantly. steped up to the pt88 and it had significant lag. my next step will be someting in the twin t72 range. i expect that to be more laggy than the pt88. i could go with a trans brake or maybe a 2 step(not sure if that works on an auto) but i dont want a race car. i want a quick spooling set up for everyday driving. so... my idea i think would give quick spool when you punch it with the full potential of the t72's up top.

2 log headers conected to the turbos, out the back of the logs have a 2.5" cross over tube that conects one log to the other. put the waste gate on that cross over.

out the exhaust side of each turbo have a 3" down pipe. have a block off on one of the down pipes. it could be a high quality cut out style block off or maybe a pair of 50mm waste gates. then on the intake tract you would have the turbo on that side of the motor have a one way flaper valve that would block air if it tried to feed back into the turbo from the other turbo and once the presure was up high enough it would let the air from both turbos into the motor.

the idea is when the truck is under lets say 10psi no exhaust would flow thru the one turbo. because the down pipe is blocked off all of the exhaust would be forced into the one turbo. it would spool fast. once it was up to a preset psi the block off in the down pipe would open and the 2nd turbo would spool up. it should spool up real fast since the motor is all up to speed and making 600+hp allready. the intake tube on that one turbo would need to have a one way flapper on it so when it wasn't pumping the air from the other turbo wouldn't push it's way out thru that turbo.

you could have the block off gate open fast(waste gates) or open slow(like the sliding gate). you could also not have it close 100% so it would be pre spooled a little.

check out my crude drawing, my woman says it looks like a *****.

 

I think that is new way of thinking about a sequential turboi set-up.
International trucks use two turbos, One is smaller for low rpm, and on larger for high rpm, they do use a valve, but it is a bypass valve on the larger turbo. the valve is controled by map, once the manifold "sees" a pre set psi, the vavle closes and forces the larger turbo to take over, the smaller turbo is sill spinng, but really not making any pressure. Kinda hard to imagine. I'll try and get some pics and specs. if anyone is interested.

 

I can't see why it wouldn't work. How well it works would depend on the operation of the "intake one way flapper and exhaust cut out" Using a couple of was gates is a pretty nice idea, how big do those things come?

Its a cool idea, Its kind of boring without you breaking parts and records lately

 

i have seen waste gates in the 50mm and 60mm sizes. 50mm is about 2", 2 of them would be about the same as one 3" pipe. 2 waste gates would be the quickest acting valve and they would last forever too. i dont think they would add much restriction.

 

Quite a few crotch rockets use electronic servo controlled exhaust valves to vary back pressure. Maybe this type of technilogy can be adapted to be used for a stop valve.
I did see a servo controlled exhaust valve for ricer stuff a while back but can't find the link yet.
I think your idea is sound.

 

I think you are better off running conventional twin setup that has 2 smaller turbos.If you look a the Toyota Supra it has a super trick[complicated]sequential setup that most of the big time builders scrap in favor of big single turbo or non sequencial twins.The sequential turbo will drive you crazy trying to make it work right.

 

i want to increase my max hp potential so i will need some good sized turbos.

if i do try it i will make it easy to pull off. the way i see it only the flaper valve and exhaust block off would need to be removed and the rest of the kit wouldn't change. the cross over pipe with the single waste gate under the truck would save me the cost of 2 waste gates and also give more total exhaust flow, twin 3" dp's and the seperate 2" waste gate pipe.

 

Better get that napkin/blueprint copyrighted

 

I'm lookin.

http://en.wikipedia.org/wiki/Image:Twinturbo.JPG

 

wow you got 1000+ hp and still want more? hope you can make it work, looks like a good plan.