Before we get too far, this is being built entirely from things that we have just laying about here at our workshop, just for fun after work, and to tackle the local 1/8th mile twice a year. The idea is to spend as little as possible and to see what works, fuel system being the only area we intend to spend any real money.

The car is a 1996 VS Holden Commodore that I got off a person to replace a set of wheels that I gave them a lend of and they misplaced one of.

The turbos are units that were replaced on engine rebuilds at work, the larger from a Komatsu S6D125 engine and the smaller from an Isuzu 4BD1 engine. I can get specs for the turbos if anyone is interested in working out how poorly we matched this whole arrangement.

The idea came about one Friday lunchtime when I said we should do something with the Commodore for fun, and out came all of the leftover turbos from under everyone's benches, those two looked like they could be fun, and I was interested in what would happen if we tried to compound them.
5:00 rolls around, and out came the welder, and by 7:30, we were out making noise.

The plan now is to slowly improve the pipework, add an intercooler and get a decent fuel system and some tuning happening as we come across the right bits.

The best part of the whole thing is that stock engines, transmissions and diffs for these things are a dime a dozen.

More photos to come as we improve things and make changes. #ad
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Subscribed. This is going to be GOOD. Is that a gm 60* v6?

 

The big point I"ll make is I think you have the turbos backwards. You really want the smaller turbo closer to the engine, otherwise it will "choke" the system off. The big turbine is blowing through the small one.

ED:

I'm guessing 3800. The intake is cool regardless, nothing like that in the states really. Did you guys ever get any 4.3L V6es down there? If so, what intakes did they come with.

 

I'm watching

 

It's a 90* V6, 3800, as Drac0nic said, we never got much 4.3L stuff here, and the only one I've ever actually seen, someone imported and stuffed in a Ford Capri, so I don't think there would be a lot of stuff just laying about.

I may have to investigate switching the exhaust plumbing around, when we were putting it together' I was just trying to remember back to the last ACERT Cat and NTTA Cummins engines I had worked on to figure out which way around it all goes, thanks for the hot tip.

 

One of the forums I'm on is a 3800 cult practically, and they would probably drool over that intake. Disappointed on the 4.3L but expected it somewhat. I wouldn't be surprised if there's an equiavelent Holden based on one of their V8s with 2 cylinders removed.

This looks fun regardless, hope to see how she runs. I'd be looking at some race fuel, methanol injection or E85 if you're going to run compound PSI. Fuel and engine management should definitely be your first investments.

 

We never got so lucky as that, we went from the old Buick 3800 to what they call the Ecotec 3800, or L31, to a 3.6 quad cam turnout they called Alloytec, as cor V8s we had the old carbi 308, then to an injected 304 they called the Aussie 5L, which was heavy on fuel and hard/expensive to wring any power out of, and from there, in about 2000, we started on LS engines, so there really wasn't any parts sharing between V6 and V8 engines locally, the 3800 had a divergent block and head design to any of the V8 engines used, and was also the only capacity we got them in, though we did get the supercharged L67 for a few years, which might help us in the persuit of a happy pressure fed V6.

As for fuel, we're in a fairly sparsely populated country area, so there isn't really easy access to race fuels or E85 even, so good old premium 95 will have to do.

Once we get a few things tidied up and get some progress happening with fuel and tuning, we'll find a time to take it somewhere and get a couple of decent videos to post up.

Hopefully out of all of this we gain a good understanding of how to do this right, and can apply our knowledge to building good reliable road going cars for ourselves.

 

The most successful setups had the compressor side of the small turbo being fed by the large turbo like this one is being done.
But he has found it works best with small turbo turbine feeding the large turbo. BUT, he routed pipes around the small turbine with wastegates to the large turbine so the small turbine housing doesnt restrict.

That being said, this combo will still work. Just wont be as effiecient as it could be.
Have a local guy to me that has a vortec supercharger feeding an hx50 holset. Its backwards, but it works well.
And can we count how many horrible cold side and hotside pipes that Sloppy Denmah has done, only to put nice stuff on and gain almost nothing.

 

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Backwards is ok, I suppose, if it works ok, which this does for now. Switching the exhaust piping around is on the cards now anyhow, thanks to you guys, and it will be interesting to see how different it is.

Anyhow, here is a little update of some pipework we changed around with some new free bits we came across, and a wastegate and blow off valve we found.

 

A couple of crappy videos I took.

 

Oh wow!

 

Small developments, small second hand turbo having a leak, has been removed, back to single. Had a closer look at large turbo, found a 1.52 A/R on the turbine housing, bad deal. Found a crate pronouncing "old turbos"on the top shelf of the pallet racking at work, I fished out a couple of different ones to try. Looking into Kalmaker for the purposes of tuning the Delco ECM, or possibly a cheap second hand EBay Wolf 3D or something so we can get some control over fuel and timing.

 

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