I believe Sav said he thought it would be a 500 RPM boost in spool. That would be great, but still seems high. Current setup is 16 PSI at 7K ish. It would be great if VVT helped a lot.

Any numbers? I think y8s tested this on a dyno a long time ago and there was a difference, I actually don't remember how much though...

big difference

https://www.miataturbo.net/attachmen...ine=1374018533

I didn't drive it very far because I thought I legitimately broke something (just forgot to plug something in instead). But my car normally hits positive manifold pressure just above 2k in higher gears and "full boost" of 6psi before 3k. With the VVT unplugged I had almost nothing at 3k, just cresting into positive pressure. And then I immediately turned around and drove home babying it. Thats the best I can do for numbers, and that on an efr6758, running a 6psi wastegate on the wastegate only.

Well I didn't think it made that big of a difference, but it sounds like I'm wrong. I REALLY hope it helps as much as you experienced.

lol I keep forgetting you're running this thing without vvt control. actually even worse: its fully retarded all the time.

there are over a handful of major things holding your car/setup back.

sounds to me that with everything you're doing, once its squared away it will go from mediocre to 5x overkill LOL

tuning afr, getting ait under control, having a sc pushing 18psi, controlling vvt, and getting the timing in check will make the car feel so different you will piss yourself

start planning a drivetrain upgrade and driving on slicks full time

Well I have a 6 speed and RX7 LSD in an RX7 case with stock 99' one piece axles right now. I would love to get the drivetrain beefed up better, but it doesn't look like there is any bolt-in solutions stronger than what I have. I dunno what transmission I should eventually install, but the rear diff, it looks like the 8.8 ford setup is the way to go. Hopefully the 6 speed and RX7 stuff holds up for a while.

And yeah, when I get all the stuff fixed and dialed in, it should be fun. :)

I intend to do this with a toyota SC14 and something big and cheap (T04 or something).

The sc14 will be mounted below the turbo, allowing intercooling of both, I also intend to spray before the blower.

SC14 also has a bypass for experimenting with it. Although I know an SC14 can do 400whp on the right setup on its own, so I dont see it becoming a restriction unless I went for the ultimate record.

Dann

I can't even picture this...Will your car have no hood?

Yeah I'm kind of confused here too. You need to intercool between the turbo and the blower and between the blower and the engine. One would argue that the intercooling between the two compressors is more important than the one between the final compressor and the engine.

huh?
I don't get that part at all either.

If you take hot air and compress it again you get REALLY REALLY hot air, which after being intercooled will just be REALLY hot air. If you intercool hot air, to be warm air then compress it again it'll be rather hot air. It has to do with thermodynamics that I cant quite remember off the top of my head. Basically compressor efficiency will be higher with lower intake temps. The equation is coming back all fuzzy right now. I'll probably wake up at 3am and remember it. :rofl:

I think making serious power (500whp) when your final compressor stage is unintercooled is a pipe dream, no matter what's happening in between the turbo and the supercharger.

If I were to attempt something like this, it would involve a low-mounted turbo and a hotside MP62. Either feed the blower through the turbo's compressor wheel or feed them both into the same intercooler. Feeding the blower with the turbo could work, but I'd be concerned about boost control.

Boost control on this setup is going to be difficult. It would probably be easier to control the turbo based on desired pressure at the blower inlet than trying to control it based on the manifold pressure.

Air filter
Turbo
E85 injection
Big throttle body
Supercharger
Intercooler
Intake manifold throttle body
IM
e85 injection again

Combustion.

Like that.

A low mount sc14 with a sidewinder manifold, kind of like crtndrftr's manifold.

Fed into a front mount, with a rear mount radiator.

I have an NA shell just sitting here about to be chopped up and a personal challenge on the aus forum to build a car that does x time for 5k. After that, Ill go nuts on it with the big turbo and blower.

Dann

Yes, EBC with reference between the turbo and blower, an sc14 will give a constant (ish) pressure ratio so controlling boost going into it is where its at.

According to my logic.

Dann

Great to see someone brave enough go against the grain and build twin charged engine. My hat's off for you sir.

Few thing's that came in mind.

1. why dont you get better flowing exhaust manifold?
2. how will you control IAT?
3. how will you control boost?

Here's a video to keep the spirit high.

To nitrodann
Why are you going to fit the SC below the turbo? Why not fit it like hotside on top off the exhaust manifold?

Then just a thought. Instead of using old school SC blower, one would use Rotrex (like in the video) with proper gearing, it would be easier to install, would create less heat and off course SC would be more expencive to buy..

Then use a teenie tiny turbo to 'spool' the rotrex?

Dann

it's a bad thought. a very bad thought.