patsmx5

iTrader: (16)

It doesn't look that bad in the pics. Guess I'll see, I think mine arrives tomorrow or friday. I'm planning to port it a bit for the wastegate if needed, since I'll need lots of flow for that. Not even sure if a 38mm gate and the turbo's internal gate will be enough, but we will see.

My goal is to be driving it compound boosted by 2/12/2016, next friday. Not sure I can pull that off, but that's the goal. I've taken a few pics, will post some tonight when I have something done worth showing. Still working on the turbo mounting system in the rear, but I got the turbo placement nailed down and a T4 to 3" adapter made and bolted up.

sixshooter

iTrader: (12)

Production cars, Group B Rally cars, and other fun things back to warbirds in WWII had both a turbo and a supercharger. They work well together.

The low-down on twin-charged engines

https://en.wikipedia.org/wiki/Twincharger

The Turbosupercharger and the Airplane Power Plant

glade

iTrader: (2)

I was gonna say, only recently have you seen compound charged vehicles become popular, I.e. the diesel crowd. So, pat, just exactly what the hell are you talking about?

And those compound systems literally put the top turbo on the other, not with 6 feet of charge piping between them, so I'm confused about how your system is going to function.

I get the theory, just confused on exactly how it's supposed to act as a twin charge. Are you feeding the rear turbo into the inlet of the forward? Vice versa? Are both being plumbed into the intercooler, and gawddammit one of em shoot push air?

sixshooter

iTrader: (12)

So, slow the whipple down to a speed where it is more efficient and rear mount a turbo at about 10-15psi so it doesn't make lots of inefficient heat either. Boom boom.

deezums

iTrader: (3)

All he needs is a small turbo up front for response, then a large enough wastegate to allow the rear turbo to spool still while letting the front turbo level out in it's efficacy island, no creep disturbing flow out back.

The lag on the big turbo and charge pipes ought to be nearly undetectable.

At least that's how I understand what he's doing now.

patsmx5

iTrader: (16)

If I did a twin charged setup that bypassed the SC, I would have a smaller SC (wouldn't need a huge one anymore) and put the turbo up front.

As the title says, Compound Boost, not twin charged.

The air path will be: Air filter, Big turbo, small turbo, intercooler, intake manifold.

The exhaust path will be: Cast Iron Taco manifold, small turbo, downpipe, catalytic converter, glasspack, large turbo, some type of muffler/glasspack, out the rear of the car.

Small turbo in normal spot, large turbo in rear of vehicle.

Essentially think of it as normal turbo setup, but at high revs, the normal turbo gets a "boost" of compressed air from the big turbo to up the HP some more.

Maybe one day, going to build a regular compound setup for now.

aidandj

iTrader: (5)

Will the big turbo be a giant restriction while trying to spool the small turbo?

patsmx5

iTrader: (16)

Yes, this is correct. It will drive like a regular turbo miata from idle until the small turbo is spooled and pulling, then somewhere around 5,000 the big one will seamlessly spool up and prop up the top end power a lot.

aidandj

iTrader: (5)

I think instead of all this you should get an he351ve vgt turbo. And run allofthe boost.

Cheap, easier, better all around.

patsmx5

iTrader: (16)

T4, 1.05 AR turbine, 77mm exducer. Hard to call it a giant restriction. My catalytic converter, or old muffler, were both likely more restrictive than this turbine while the little turbo is spooling.

aidandj

iTrader: (5)

I meant the other way. Intake restriction.

Do an he351ve instead.

deezums

iTrader: (3)

Wouldn't blowing through the little turbo overspool it, choke it, whatever? Wouldn't it be better to just Y them together at the intercooler?

If the big turbo is stalling little turbo spool you should look into vacuum operated wastegates, then you could hold big turbo wide open till 4K, let the little guy breathe. A little electric vac pump should be enough to actuate it.

aidandj

iTrader: (5)

Y them toghether would send all the boost back towards the big turbo.

Run an he351ve

patsmx5

iTrader: (16)

No it won't, it will help it actually.

patsmx5

iTrader: (16)

Blowing compressed air into the small turbo won't overspool it, the turbo will just compress it further and send it to the intercooler. But all that extra air has to escape, and the T2's wastegate/turbine is too small. I'll be running two wastegates up front, a 38mm external gate, and the T2's internal gate as well. I don't know if this will be enough, will have to build it and find out. Going larger than a 38mm gate would require some extra work so doing the 38 for now.

deezums

iTrader: (3)

My only advice is lay out the IWG flapper on the turbine housing, trace it out as much you can and open the hole up to within 1-2mm of the flapper diameter. Diameter is more important than blending, everything in the turbine housing is under pressure and will blow out if blended or not.

For some reason all the china turbos I've seen have midget holes compared to the flapper. I assume it's because they're meant to be universal, lots of output flanges need to work.

patsmx5

iTrader: (16)

Thanks, will do. I'm gonna do the same on the external wastegate part of the manifold, it's china and the hole is maybe 1" for a 38mm gate... Very undersized.

patsmx5

iTrader: (16)

Also I got the turbo mounting system like 95% done. Going to finish that up now. Then I think run the boost pipe to the front if I have all the reducers to do so.

stefanst

iTrader: (1)

Pictures of what you have so far please? I need to see it to believe it!

18psi

iTrader: (76)

My guess is smaller turbo's hotside will choke and you will need to run massive ewg or something. and route it back into exhaust otherwise big turbo won't do nothin