turbo specs

[bonestocksr20]

I have a guy trying to sell a set of 300zx stock turbos. He is selling them for $150, and claiming that they are safe to 21psi. I dont believe that these turbos can handle this much boost, and is this a good price for a set of used turbos?

[mtcookson]

The Z32 Twin Turbo uses T2/T25 or T22/T25, I can't remember the turbine off hand. I know the compressor is definitely a T25 though. $150 doesn't seem bad as far as the price goes but make sure they're in good shape. You can get rebuilt kits for them for a little less than that price but if they're overly worn, the rebuilt kits won't work.

As far as boost limit... I think 21 psi might be pushing it. I don't recall seeing any limits of them off hand and haven't seen a compressor map but I bet the limit will probably be less than 20 psi. I'll try finding some maps though to see where the limit will be.

Edit: From the T25 compressor maps I can find, it looks like most will support that amount of boost but will be somewhat inefficient in that range. The T25 55 trim compressor map I've found doesn't seem to handle that high of boost but the 60 trim and 45 trim is said to. I'm not sure which the Z32 has though. Off hand, I'd say that might be pushing it a bit for the stock turbos though... especially if they're a bit worn.

[brizanden]

its like 12 for a single t25... at like 13 they blow apart.

[mtcookson]

Now that's definitely not true... Z1 Motorsports has boost jets that puts the boost about 15 psi and I'm sure there are plenty of people running more than that in their Z's.

[brizanden]

i said single t25. isnd boost cumulative on a tt setup? on a sr if u boost it past 13lbs ive heard over and over again the ceramic fins blow apart. its just not built for that.

[mtcookson]

Ahh... the ceramic turbos... yeah, those I definitely would not push very hard. The Z32 T25 has the aluminum compressor wheels and metal turbine wheels, which allows for the higher pressures.

Also, I'm pretty sure each turbo is putting out xx amount of boost each (i.e. if you're pushing 10 psi, both are pushing 10 psi). I'd have to measure boost at each turbo to know for sure, but I'm pretty sure the twin turbo setups aren't cumulative (at least in the standard style setups).

[brizanden]

oh im prolly thinking of how the rx7 runs its turboes. What sequential? I had no idea z32 t25s werent ceramic. Well ****... if they made a non ceramic t28 on a z i would be all over one of those right now lol.

[mtcookson]

A sequential twin turbo setup is where you have a small turbo and a big turbo. The small one spools first for quick power then the larger one spools for top end power.

You can also have a compound twin turbo setup where the compressor outlet of one turbo runs to the inlet of the second turbo for some crazy boost. This setup is most commonly done on diesel engines that run high boost, from what I've seen.

[Bronze MFP]

TT setups, the ariflow is cumulative, the pressure is not. so 10psi, is 10psi coming from each compressor, not 5psi from one and 5 from the other. airflow, say at 10psi, each is flowing 200cfm, then you would getting 400cfm fed to the motor.

[mtcookson]

My post whore post for the day.