Hi, mulling over which turbos to use on my engine build... I have a set of recently rebuilt factory auto turbos which are in perfect condition, and pretty much ready to go (motor is just about ready to bolt turbos on). Or on the other hand I have recently bought a factory TT Manual zed as a parts car. The car is still complete so I'm not entirely sure what turbos are fitted, but the rest of the car is stock standard aside from the exhaust and wheels so its a safe guess that they are standard. However I also don't know the condition of the turbos. So basically it comes down to the difference between the turbos. As I understand it the auto turbos have a slightly smaller exhaust housing, giving quicker spool but less top end power, but how much difference is there really? My target for the build is a strong but reliable street motor, if I hit 300RWKW I will be stoked. The rest of the motor is Wiseco pistons, Eagle rods, Manual TT heads and cams, Nismo 555 injectors, AMS sidemount coolers and split dump pipes. Opinions, ideas and experiences welcome!
With the manual turbos you'll be lucky to hit 250 KW ATW, autos less. I'd take off the manual turbos, give them a good look over and fit those if they're up to scratch. Alternatively there is a pair of GReddy turbos for sale on the forum for less than a grand, better choice again to pick up those. You'd probably clear 320 at a guess.
You'll need 1000cc injectors and e85 to hit 300rwkw on standard manual turbos. In your shoes id find an extra $1500 and get the manual turbos high flowed. You already have the supporting mods to run more boost.
Ok, I was thinking 98 octane on about 17 PSI or so would get me close... As high flowing goes, is there any advantage high flowing the manual turbos? Or will it be the same if I did it to the auto turbos which are sitting on the bench? (Read: less work to get them out)
In Australia that gets you closer to the 250-270kw bracket, not enough ground up unicorn in our fuel. IIRC at the UAS dyno day a few years ago the most powerful car with original turbos was about 270kw, some doubt the turbos had original cores in them though. Once you get the thimble turbine wheel out of the way 300kw on 98 with under 20psi is more reasonable. For high-flowing you can get the autos done then put the manual turbine housing on later, the wheels are the same size but the auto has a smaller inlet to the turbine.
Auto turbos are a waste of time. Also you wont get 300rwkw on 98ron and stock turbos. E85 and 20psi will get you close. Aarons car made that on factory dumps, mine around the same but its all due to e85.
Thanks for ideas guys, I got the parts car driving today so now I'm not sure if I want to part it out anymore... One other question, is there an easy way to identify manual or automatic factory turbos? Different A/R values or something?
Yeah, .54 for auto and .63 for manual on the turbine side, stamped on the inside of the scroll at the manifold end so need to pull them off to check.
2nd this - I previously had highflowed auto turbos and wasn't able to boost past 17psi because the turbos became a restriction. Now running manual GT525s and a massive difference at the same boost and ability to go higher. Happy days!
