Turbonetics P-trim T66 BB...opinions/info needed

[Stage24u]

I have had this turbo in my garage, and just dusted it off to actually ID it last night.

Turbonetics T-66 P-trim BB
.96 AR
4 bolt

Hp rating?
Stall needed/recommended?

Anyone ever max one of these out @30lbs+ on S2 motor?

Prob not worth putting on my S2 motor, BUT if I did, what could/would/should I expect w/ a 4000 stall?

I have zero experience with this turbo, and most info I found was from ricer forums.

 

[bison]

I ran a 6668 out on one of my engines. It had the t76 cover. It couldn't keep up over 5400rpm and suffered boost fall off with no wastegating. It was on a 233ci with good heads and cam that peaked around 5400rpm. The turbonetics 66 compressor wheel leaves a lot to be desired. There are a couple of cast 66 wheels out there that will flow more than the turbonetics wheel. It made 687whp@24psi (it wouldn't make more boost in the dyno) and low 10's@137mph were the best I ran around 26psi on the same engine. It's a 9 sec turbo with good hook. If it has the small compressor cover (like most seem to these days) it's impossible to get max flow out of the compressor wheel. The large cover has 8 bolts and has a 5.5" diffuser. The p trim wheel is a better match to the compressor. The larger ex wheel I ran out flowed the compressor. About two years later I ran the 6680 up to 655whp on a different engine. Then the same day I switched to an old 72 with a clipped p trim and it made about 680whp peak and picked up over 70whp over 6000rpm.. Definitely not an ex restriction with the t-netics 66, just a shitty wheel that takes a lot of energy to drive. The clipped p trim is good to at least 78lbs/min on the proper built engine . Looks like the t-netics 66 compressor is good to about 74-75lbs/min. The 72 I used if it was a 68 turbine it likely would have made over 700whp with the same or slightly less boost. At higher boost it with the larger turbine it would have definitely made more power. With the small compressor cover I would expect the mass flow to be limited to less than 70lbs/min no matter what was done to tye and increase it. The drive pressure for the compressor is too high with the small cover and 65mm turbine. I observed 600whp on one engine with the small cover turbonetics 6665. It had severe boost drop off over 5300. On another friends engine we observed about 70lbs/min out if a te45a (Garrett cast 66, clipped P) e cover @27-28psi. When we switched to a 7068 with t76 cover it made about 50whp more at 2 psi less boost. With the boost in the high 20's the car trapped in the high 130's. All examples except the 6665 which used a 3 bolt .82 ex housing were 3 bolt .85 a/r and used PTC 9.5" that stalled around 3000@0 and 5400@ full hit. All were ball bearing cartridges. I don't known if cam timing and CR was optimized in this example. On the prior examples it was.