Twin turbo questions

[Guest bastaad525]

Just out of curiousity... could someone here explain to me the how's and why's and differences between a sequential turbo setup, such as on the last gen Supra Turbo's, and the turbo setup on the last getn 300ZX TT's? Do they work differently at all? I always thought the purpose of the Supra style setup was to have a smaller turbo, that would spool up fast for lag free performance, and a bigger turbo to come on after that for max power, but I remember someone here, Tim240Z I believe, mentioned in one thread or another that this setup actually produced MORE lag, is that right? How does the 300ZX TT setup work? The turbos on the 300 are one on each side right? Are they also sequential?

[Moridin]

From what I remember, the 3rd gen RX7 and MK4 Supra both had a sequential setup. The Z is done in a more traditional way (as traditional as you can get with twins).

 

Hopefully, to answer your question, I'll relay what my friend said about his Supra. He has the ability to change from sequential to standard (by changing a fuse or two), so he can tell the difference. The sequential had more lag, but got him better gas milage, because he wasn't in the second turbo's boost as often. With the standard setup, boost came on sooner, making more power earlier in the rev range.

 

Maybe someone here with a little more experience can validate what I said, or correct it.

 

Hope this helps. I also believe there's a huge MK4 Supra site with a ton of info.

[SleeperZ]

Turbos on the Z32 are parallel, like a typical twin setup found on a V8, with one cylinder bank feeding one turbo. This is done for plumbing ease, and will not spool as fast as an equivalently flowing single turbo. I'm not familiar with the stock MKIV Supra setup, but I believe they have some sort of trick controller that spools the smaller turbo first, then opens the big one. I don't know how the plumbing is done at all. As you know, one of the better upgrades for the Supra is a big single turbo.

[280Zen]

Sequential Twin Turbo charging means #1 turbo charger gets pretty much ALL the exhaust from the start, providing pressure, and then a gate opens allowing exhaust to move through the #2 turbo, until it has full spool-up, at which point the whole thing opens up and both pressurize the intake.

[Guest FATEV12]

280Zen is correct. I owned a 95 supra twin turbo so I have some background with the sequential setup. The sequential setup minimize turbo lag with two small-SAME SIZE turbos. One is set to spool just pass 2k rpm and the second kicks in around 4k rpm. Both spools together from 4k rpm onward. Physically you feel two boost sequences. Many have bypass the sequential setup in their 4th generation supras to get both turbos spooling simultaneously. This increase turbo lag but has one huge boost surge instead of in sequences.

 

Mike