Ok, so if I'm scratching the ZZP stuff off my list in favor of a couple hundred bucks of steel and some spare time, that brings me to my next question. I had been looking at just slapping the ebay GT45 on there until I could save up for a better turbo, but if I'm not spending the $1100 for the exhaust piping, that allows for a little more on the turbo budget, but I'm not entirely sure I WANT to spend more.
The V8 guys seem to love the ebay turbos, I've run an ebay 16G on one of my cars for a couple years no issues...and at $263 shipped that GT45 is basically a disposable turbo anyway. I will *probably* be twincharged and double intercooled, so I'm not too worried about exploding turbo parts getting into my engine. I've always been super interested in a twincharged setup and have some ideas for a different route to go with it than I've ever seen. I've always been an experimenter...they aren't always good experiments, I learn what NOT to do a lot, but every now and then I end up with something that actually works and then all the haters start oohing and aahing.
Anyway, what are the thoughts/experiences with turbos? My biggest concerns with the (dnamotoring) GT45 are that it isn't water cooled, and it's advertised as 1000hp, but based on the specs, it looks more like a 600hp turbo. I couldn't find many dyno sheets on it, a couple guys saying they've made around 650. My goals are higher than that. I have had the car on methanol pushing that little M90 to the ragged edge (5% crank overdrive, 2.55" pulleyed gen V with an A/C refrigerated intercooler reservoir) but will be downgrading to E85 for this turbo setup, so I basically have a 1000HP worth of E85 fuel system in place. I basically plan on doing the opposite the conventional wisdom in terms of twincharging. Instead of spinning the M90 slower to rob less power and let the turbo do the work, I want to get my little M90 spinning just as fast as I can through the early RPMs to spool that turbo and then open the bypass when the turbo hits X boost level by utilizing a boost switch, a vacuum solenoid (probably evap purge solenoid or something), and a clutch vacuum reservoir from one of my other parts cars. The turbo's wastegate will be referenced directly to manifold pressure to prevent overboosting.
In theory, I'll get instant boost pretty much off-idle (which I do currently), which should spool even a huge turbo pretty quickly, and by 3000-3500rpms the turbo will have taken over, the bypass valve opens, and the supercharger is effectively idling making only a couple pounds of boost while the turbo is doing the heavy lifting. Will it work? Maybe, maybe not...but it's a lot easier to remove the supercharger later than to build the turbo setup without it in mind and try to add it after the fact. Will be a fun experiment/learning experience. So for what I'm wanting to do, any advice on turbo selection? I do really want to go big, but I'm thinking the thing to do might be to just go with the cheapo GT45 for the "proof of concept"/experiment phase and upgrade to something more durable/larger/better later on. I'm typically one to push my stuff for all it will deliver, and I have the supporting mods for it, so I'll probably find the limits of that turbo. And maybe the limits of a 4t80e in the process.
