UPDATED!!*DYNO NUMBERS* Comparison of Comp Turbo Billet 88mm CT6X-88 & GT91 Garrett!!
08-14-2012, 02:29 PM
#161
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Same here, they are going to send me out a modified ct5. Still t4 but with a 88mm turbine wheel. Im going to give it another try if it fits without me changed the dp. If that doesn't work im done. Borg warner it is
08-14-2012, 03:24 PM
#162
Ya I hear ya thats why I posted my example with a smaller housing (opposite to yours). By the flat hp curve could you assume that peak power was reached and a housing change would do nothing? All other things, IAT,BP,boost duty being monitored?
Amazing how you "think" you are going to do better and end up not.
Amazing how you "think" you are going to do better and end up not.
He now runs a X275 PTE 88mm turbo with a 132mm turbine.
08-14-2012, 07:03 PM
#163
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When will you recieve the modified ct5? You have a 370ci right? I think i'm gonna go with a 94mm turbine on mine but would be interested in seeing what your car does with the 88mm. If the 94mm doesn't work for me i'm going Borg Warner with the batmo wheel. We shall see!
08-14-2012, 08:44 PM
#165
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Your in LA, not sure how close you are to Comp but you can possibly get quicker turn around and some results faster.
08-26-2012, 08:33 PM
#171
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What's the latest with the new housing??? I took my 8079 t4 back the other day and went with a 8094 ct5 t6 with 1.39ar. I think it's gonna work out fine for my combo. Sprayed01 was having 2:1 back pressure and maxing out at around 5300rpm (i think?) with the 8079 t4 @17psi on his 370, so theoretically the 94mm turbine with a t6 housing and 1.39 ar should be a lot lower on backpressure on my 364 lq9 and should spin a lot higher...HOPEFULLY...WE SHALL SEE! I'm gonna start going hard on my project so i can finish up soon and post results for you guys asap.
08-26-2012, 08:49 PM
#172
08-26-2012, 09:36 PM
#173
I had another thought since i use these and used to run them back in the ITS days
I think the turbine is TOO BIG, and the straight cut wheels dont grab enough air, its just too open of a hole. This combined with the fact that the billet wheel is just aggressive as **** and takes X amount of torque to turn, instead of the exhaust being grabbed by the wheel and applying tq, it just flows through with little energy transfer, thus requiring more pressure, as low flow high pressure=high flow low pressure
This also explains why going to a cast wheel which is far less aggressive and requires less tq and more RPM, and as the wheel is at a higher RPM it will get in the way more and transfer more energy at lower pressures.
I am going to try out a CT43 7475 with the old cast wheel and turbine I had used seperately in the early 2000's and they worked great, always thought they would work well together. It will be a rearmount
I think the turbine is TOO BIG, and the straight cut wheels dont grab enough air, its just too open of a hole. This combined with the fact that the billet wheel is just aggressive as **** and takes X amount of torque to turn, instead of the exhaust being grabbed by the wheel and applying tq, it just flows through with little energy transfer, thus requiring more pressure, as low flow high pressure=high flow low pressure
This also explains why going to a cast wheel which is far less aggressive and requires less tq and more RPM, and as the wheel is at a higher RPM it will get in the way more and transfer more energy at lower pressures.
I am going to try out a CT43 7475 with the old cast wheel and turbine I had used seperately in the early 2000's and they worked great, always thought they would work well together. It will be a rearmount
08-27-2012, 04:58 AM
#174
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billet compressor wheels are much lighter, so should be easier to turn. The profiles arent that much more aggressive, they just allow a higher volume of air because there is more room for blade, as opposed to dead casting.
But generally a billet wheel should be easier to turn for any volume of air compared to a cast wheel.
But generally a billet wheel should be easier to turn for any volume of air compared to a cast wheel.
08-27-2012, 11:09 AM
#175
if you havent seen the comp wheels in person that is not really the case.
I have had the 67mm and 74mm billet and cast wheels side by side and the blade angles and openings are much higher and quite a bit more aggressive. I went from a cast 67 Q-trim to a billet 67 Q-trim, same turbo same everything just a wheel change. BP went UP, not down and we had to switch from a 1.0a/r to a 1.32a/r to keep BP the same.
The compressor is spinning a much lower RPM to make the same boost which will require more TQ to be applied to the turbine, resulting in higher BP.
Just putting it out there Ive been kind of perplexed about this for almost a year and this is all I can come up with
I have had the 67mm and 74mm billet and cast wheels side by side and the blade angles and openings are much higher and quite a bit more aggressive. I went from a cast 67 Q-trim to a billet 67 Q-trim, same turbo same everything just a wheel change. BP went UP, not down and we had to switch from a 1.0a/r to a 1.32a/r to keep BP the same.
The compressor is spinning a much lower RPM to make the same boost which will require more TQ to be applied to the turbine, resulting in higher BP.
Just putting it out there Ive been kind of perplexed about this for almost a year and this is all I can come up with
08-27-2012, 11:16 AM
#176
08-27-2012, 11:28 AM
#177
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if you havent seen the comp wheels in person that is not really the case.
I have had the 67mm and 74mm billet and cast wheels side by side and the blade angles and openings are much higher and quite a bit more aggressive. I went from a cast 67 Q-trim to a billet 67 Q-trim, same turbo same everything just a wheel change. BP went UP, not down and we had to switch from a 1.0a/r to a 1.32a/r to keep BP the same.
The compressor is spinning a much lower RPM to make the same boost which will require more TQ to be applied to the turbine, resulting in higher BP.
Just putting it out there Ive been kind of perplexed about this for almost a year and this is all I can come up with
I have had the 67mm and 74mm billet and cast wheels side by side and the blade angles and openings are much higher and quite a bit more aggressive. I went from a cast 67 Q-trim to a billet 67 Q-trim, same turbo same everything just a wheel change. BP went UP, not down and we had to switch from a 1.0a/r to a 1.32a/r to keep BP the same.
The compressor is spinning a much lower RPM to make the same boost which will require more TQ to be applied to the turbine, resulting in higher BP.
Just putting it out there Ive been kind of perplexed about this for almost a year and this is all I can come up with
08-27-2012, 01:45 PM
#179
With the straight cut wheel the air can simply flow through with just the angle on the outlet end of the blade catching the air, which puts very little rotation into the wheel.
Back in the day (ITS turbo) a freind of mine used a 74 Q-trim on a 3.2L v6. It would not come up on boost and had alot of BP, which is what started the reasoning I have been saying. He picked up a 75mm turbine like I have and machined the exducer to 68mm (Q-trim) and put it together, minor machining in the turbine housing. This thing flat out worked, power everywhere, spooled instantly, had to go up to the biggest turbine housing they made which ended up being a 1.5x a/r that he machined to fit
If I remember right the Q-trim 68mm and the 75mm wheels looked about identical, just cut to different sizes, so all he ended up with was a 75/68mm Q-trim vs a 68/68mm Q-trim, and the results were very conclusive with that being the only change. Once that was taken care of the 74mm compressor made major power, over 800whp and the backpressure was less than half of what it was before with 10# more boost
Like I stated previously, this might be totally off base but Ive been thinking about it for years and its the only answer. I guess if the big wheel doesnt work for you guys I would MAKE them to machine the 88mm turbine into a 88/79 and try that, at the very least this can be free testing for them and IMO a 88/79 and the 94mm machined to a 94/88 would be some of the best turbines on the market. Provided what I am talking about is correct.
Gary
