Thread: compound turbo set up

Chief
It's nowhere near the same as when the Garrett was running on its own. I have my doubts with this Schwitzer though.

Dougal
Not giving up yet , will give the compound set up a chance. I had thought of getting an LP turbo with a waste gate and running it so the waste gate is open from idle and closes when boost builds giving the HP unit time to quickly build boost. Will post HP to air results tonight.

Justin

Originally Posted by DRanged

Chief
It's nowhere near the same as when the Garrett was running on its own. I have my doubts with this Schwitzer though.

Dougal
Not giving up yet , will give the compound set up a chance. I had thought of getting an LP turbo with a waste gate and running it so the waste gate is open from idle and closes when boost builds giving the HP unit time to quickly build boost. Will post HP to air results tonight.

Justin

Hmmm interesting....as dougal said don't stop now
What would the LP hot side A/R be out of curiosity?

Not sure on the LP hot side A/R but the HP exhaust housing is about 115 dia. The LP is about 165 dia, but after a quick test with the HP to air it builds boost as it used to, although still sluggish . So with the intake off the LP at idle you can see the blades turning possibly 2-3 revs a second and you can stop it just by touching it. So in conclusion the best thing for this Schwitzer is tow it behind the quad bike for a couple of hours smiling immensely , then leave it in the paddock for the tractor to finish off.

Now I am no expert but I think I need a smaller turbo in the exhaust side that can process the exhaust better than the Garrettt hence spinning up the air side quicker on the LP.

I'll give it one more crack, so boffins heads down any suggestions??? The local diesel guy has some s/h units but we need some Sizes

Justin

I think you need a bigger LP turbo compressor. This will be less restriction to the intake and exhaust while the little one is spooling up.

Or, fit a bypass valve so the little one can suck air past it until the big one is on boost.

Dougal I did think of some sort of bypass but I think this Schwitzer is still restricting exhaust. Must do so maths maybe . I might put a point in the exhaust and measure pressures . What do you think would be the best spot

Justin

Restricting exhaust is the smaller of the two evils. Once you get the air in, it will be forced out the exhaust. Pumping against extra exhaust pressure does cost power, but that's only a concern once you have enough boost.

I would thread two ports in for exhaust pressure, one in the manifold (or adapter to the HP turbo) and the other between the turbos. Swap your gauge between them as needed.

I would say that the schwitzer's hot side may be suitable but as dougal suggested the cold side may be the problem....after my testing the gt2052s hot side did prove to be a tad restrictive which may also impact the functioning of the LP turbo....

ok
Seeing as I cannot find any info on the Schwitzer (LP) turbo I will head down to our local diesel guy and see what he reckons. He also has some s/h turbo's so I can get the sizes and go from there. Worst case it will be a bonnet off, bolt on different turbo,s and start a spread sheet.

Dougal, Cheif any ideas for a size to start with or look out for??

Justin