View Full Version : TO4B for the KA Pros and Cons with this turbo

02-20-2003, 12:35 AM
I'm think about buying this turbo for the KA. And I would like all to give their info on helping me with this turbo.

The compressor A/R is .60 and the turbine A/R is 1.15 . The compressor has a 51.6 mm inducer and a 70 mm backwall and the turbine wheel has a 74.2mm inducer and a 64.6 mm exducer with a P trim

Please help


02-20-2003, 01:15 AM
Turbine side is far too large. Much too large. That's a turbine that a 700rwhp Supra might use.


02-20-2003, 01:18 AM
asad do you think that the stock KA would not be able to spool this mother up and would you buy it for $250 and change the trubine side later.

02-20-2003, 02:52 AM
The compressor A/R is .60 and the turbine A/R is 1.15

whoa is it off a diesel?

02-20-2003, 08:36 AM
The turbine is the pricey part of the turbo...if you buy this turbo, then get a new turbine wheel and housing...you're looking at the price of a new turbo that really fits what you want.

Turbine wheels include the shaft...and cost ~150 new. Turbine housings cost ~200 new from Turbonetics. If the turbo is rebuilt properly, then the compressor should be balanced independently from the turbine wheel/shaft...so you could just swap wheels.

Perhaps you could just get away with swapping turbine housings...and maybe you can find a deal on a used, blown turbo with the housing you want...and just swap over. That is the only way it'll really be cost effective.


02-20-2003, 10:15 AM
Hey dennis i tought you can't buy from turbonetics direct any more ..... i was told you have to go and get them from a dealer.

02-20-2003, 02:06 PM
I dunno...but it probably is better to go through a dealer.

The highest level of account with Turbonetics (who buy a lot) get 40% off retail. With a regular shop account, you get 20% off retail On a $200 item...I found you can get it cheaper through the top tier guy than through a regular Jobber account...last time I bought something from Turbonetics, I had Joel at Diesel Injection order it for me...and got it for ~30% off list.


02-20-2003, 02:16 PM
dennis thanks for the info

Well i have called around and with the 1.15 on the turbine side the turbo will spool up at 4200-5000. i'm going to take this chance and be cheap and use this turbo ..... if it doesn't work then i'll just have to change the wheel and turbine housing....... I would do it right but working with a really tight budget right now.

02-20-2003, 02:31 PM
Well i have called around and with the 1.15 on the turbine side the turbo will spool up at 4200-5000.

I think 5000 RPM is optimistic. Look, for example at the NSport kit -- it uses a T04B with a 0.58 A/R turbine housing, and likely a smaller turbine wheel (my guess is O-trim, but nobody's been able to confirm that for me), and it reaches 6 psi at around 4000 RPM. Granted, the Nsport setup also uses an on-center turbine housing which is supposed to be less efficient, but still... a P-trim/1.15 is BIG.

02-20-2003, 02:42 PM
asad i have been trying to find out the nsport spec on the exh. side with no luck too.

I guess the only way i will know for sure is to put the trubo on and hope for the best. I called Turbonetics and they said i should stick with a .58 on the turbine side and they said it should spool up in 3200-4000. I guess the only real way to figure this out is to sit my ass down with my friend and do some math, even then it's only in theory.

02-20-2003, 03:08 PM
1.15 is huge...just do it right the first time...other wise you are just inviting a big pain in the arse...

i can't see that turbine being very effective

02-20-2003, 03:13 PM
don't waste your time with that turbine.

02-20-2003, 03:22 PM
Remember...the KA dies off about 5800-6000rpm. So you spool by 4800-5000, then have good power in a burst for 1000rpm, then SHIFT...wait...wait...then a little burst again....SHIFT.....wait.....wait....

It would suck around town, the area under your torque curve would be limited, you'd get owned by stock SRs even if you were running 10psi...

Don't get that turbo.

Buy it right the first time - T3/TO4E, 50 or 57 trim, .63 A/R exhaust side. $550 from Cheapturbo.com...

Later - Brian

02-20-2003, 03:42 PM
This is the problem i have a manifold drilled for a t4 so i'm suckusing a str8 t4 turbo only. so i guess from all the info you guys have given i will not buy this turbo and look around for another turbo

02-20-2003, 03:55 PM
Swapping turbine housings isn't a problem...if you can find the right housing cheap...this may be an ok deal.

02-20-2003, 05:10 PM
I would have to change the wheel and shaft and the exh. housing so by this time it would be running at another 300 bucks maybe....

Hmmmmm i have to make a choice, but thanks all of you for ur info.

02-20-2003, 06:13 PM
I've been seeing this alot and I just want to clarify something.

Boost threshold is when the turbo actually begins to build positive pressure right? So when you guys are saying "that turbo will boost at XYZ"

are you saying thats when you will get full boost? Or the boost threshold has been reached?

02-20-2003, 06:16 PM
most of the time they are talking about target boost.

02-20-2003, 06:32 PM
One other thing any of you running ka with a t4 by any chance will my cusco bar clear the turbo with a rev hard manifold

02-20-2003, 09:20 PM
this turbo has no pros only cons. the hot side is way too big, unless it's an all out drag car. you won't be able to spool it w/ the exhaust energy you put out. you won't be able to rev high enough to hit it's sweet spot. you'll fall out of boost between shifts, meaning your car will fall flat on its face btwn every shift. even super high hp street supras don't go w/ an a/r that big, the trend for street cars these days is to go w/ a smaller turbine for better spool. only the rotary guys can really get away w/ a turbine that big for street use.