Jim...I like your design...seems a little complex though...I don't know what numbers your looking for, but have you thought about going with Parallel twins, go a step smaller on the the turbo, like a 67, then use just the fuel solenoid and a small jet (like a the jet that would go with a 25shot), tied into a WOT switch and a pressure switch, so it sprays in fuel that will fatten up your mixture below like 5psi, which all that fuel can't burn easily in then CC, and it should help the spool on your turbo. That would take care of your day-day driving spool too if you didnt put it on an arm switch so its always working...I don't really know...just a thought

 

It will work, a similar setup has been done . Wastegates should be a pair and place them on the logs themselves. Next move the downpipe flap to the log at the turbine inlet.

 

twin 68's are barely bigger than the 88. if i am going to do this i want to give myself some room to grow.

i am running megasquirt wich is a fully programable speed density set up. i can add as much fuel as i want any time i want. i tried more and less fuel and never really got much change in spool up time. my timing is still on the stock pcm so it isn't as easy to mess with. there is probably some gains to be had optimizing my timing in the lower rpms and lower boost settings.

 

I think they are mostly hype... Vapor Ware or at least I haven't been able to get any info on them MAP's sizes availablity ect..

 

I know Aerocharger's old VATN turbos worked, and they actually published maps of them too. On paper they had crazy-fast spool times, but I've never experienced one first hand. Besides the biggest ones they made could only feed smaller engines. If Garrett's are similar then I would go that route. Hopefully they'll spill the freakin' beans.

 

We have some VNT turbos here off some of the diesels, like the Powerstroke and others. Typically they are pretty much very complicated piles of junk. They are not very reliable or at least so far.

 

Could you elaborate further? Are these the ones that are electronically controlled via a turbine angle sensor? Who are these made buy? If these are the ones Garrett keeps boasting over then it's nice to finally hear some info on them.

 

bump for moregrip

 

haha, it's on now

 

i think the wastegate/flapper on the secondary turbo should go between the engine and the turbo, not in the downpipe, because you dont want all that exhaust gas backing up through the turbo. just block it before it gets there and send it over to the other side. this is more or less how the sequential system on the supra works. but its a very complicated system of vacuum lines and pipes. and most people take them off, or disable the sequential operation immediately. i think its a neat idea because it hasnt been explored, but i think you might be able to get good-enough results with the right sized twins.