DIY Sequential Turbos

[kugzs]

Just wondering what the deal is with running different sized turbos on something like a 1J or a 1G?

thanks

[TA-022]

from my understanding its just a case of mount them like the twins normally except with one being smaller than the other the smaller one will spool faster helping to also spool the larger 1.

Parts I don't understand is how the smaller turbo doesnt become a restriction once its ran out of puff and the large one continues to power on. ?

[Norbie]

You're both misunderstanding the concept of sequential turbocharging, which in almost all cases is done using turbos of the same size (this is definitely the case with the 2JZ). The sequential operation is acheived using a system of ECU-controlled valves which direct all exhaust flow into one turbocharger at low load/RPM, and at a pre-determined load/RPM point allows the exhaust gases to flow through both turbos. This is a pretty simplified view of the process - getting it to work smoothly and seamlessly is actually pretty complicated, which is probably why no-one to my knowledge has put together a home-grown sequential setup.

Short version: you could do it, but you'd need to spend countless hours in R&D to make it work properly.

[kugzs]

okay, so a DIY 2JZ-like setup is a no go, but what about a setup involving different sized turbos. Is, as ta022 mentioned, the smaller turbo running out of puff going to be the main factor limiting the success of such a set up? What about if the two turbos are not significantly different in size?

[o_man_ra23]

If you run a big wastegate for the smaller turbo and put an analog ECU control to it, then its not a problem. I am considering a setup like this myself, but will be a number of years before it is realised.

Cheers, Owen

[thanhngo]

I am pretty sure on my previous rx7 it had 1 smaller turbo and 1 bigger one but only slighty. Hitachi 10 and 12 or something like that...its been awhile. Anyway that is just control by a vacuum solenoid system and acutators. If you have enough aux outputs on an aftermarket ECU you probably could control them. The PowerFC P&P for the RX7 allowed you to control and tune the transition points.

You can get them for around $200-300 a set including manifold Cosmo had them FD3s. Series 8 rx7 ones are highflowed from factory.

I liked Sequential turbos boooooooooost with minimal lag.

[joecoolmk2]

with the two different sized turbo's, what if you plumb the wastgate of the smaller turbo back in front of the bigger turbo?

[o_man_ra23]

with the two different sized turbo's, what if you plumb the wastgate of the smaller turbo back in front of the bigger turbo?

That was my plan... just didnt word it right, I reckon it would work, and would be well worth looking into.

Cheers, Owen

[IN 05 NT]

I am pretty sure on my previous rx7 it had 1 smaller turbo and 1 bigger one but only slighty. Hitachi 10 and 12 or something like that...its been awhile. Anyway that is just control by a vacuum solenoid system and acutators. If you have enough aux outputs on an aftermarket ECU you probably could control them. The PowerFC P&P for the RX7 allowed you to control and tune the transition points.

You can get them for around $200-300 a set including manifold Cosmo had them FD3s. Series 8 rx7 ones are highflowed from factory.

I liked Sequential turbos boooooooooost with minimal lag.

that the same as the T6 volvo engines, one tiny lil sucker, then ine medium sized one....

blake