ct26 max psi

[TurboFreak]

so hey im in pretty much the same boat as the original poster:

aside from whether or not the stock ct is capable of 20psi, for whatever amount of time,

and aside from the differentiation of flow and boost pressure...

we know what were flowin with and what were flowing into here: stock rebuilt blocks with all new gaskets, yet were also using a 20 y/o turbo. now, assuming the turbo is in relatively good shape, do you all think its safe and reliable to flow 12psi on the daily? im assuming i couldnt hit anything above 12 right now due to fuel cut, and i really wouldnt go any higher anyway for fear of limited turbo life. but does 12psi sound reasonable to everyone here? driving somewhat conservatively, giving it a little throttle here and there, never redlining it, rarely racing it...

should i go with 10 or 12? i guess the obvious answer is that flowing less boost is gonna make the turbo last longer period.. but would you call 12psi a feasibly reliable dd boost level?

thanks guys.

aaron

12psi is a safe boost level for a good condition CT26.

 

[Nihiliz]

in what reality?

On the 7m it will NEVER get to 20 psi. No fucking way. The 7m is already out breathing the ct26 at 14psi. as it goes down to 12 psi by 6500 rpm redline.

my old supra mk3 (7mgte) was boosting 22 PSI with a 60-1 trim CT26 made a nice 550ish hp car

 

[figgie]

my old supra mk3 (7mgte) was boosting 22 PSI with a 60-1 trim CT26 made a nice 550ish hp car

That is not a CT26 is it. Once you modify the compressor wheel. CT26 only in the housing but definetly not flow.

 

[suprarich]

I never seen my name mentioned so many times in one thread that was not a Rich roast.

My ct-26 would do 20 psi as measured by a mech. boost gauge. Perfectly accurate I cannot say. I would say I had it set for 20 psi, but would only see a spike for a few seconds at a time, in each of the three gears my auto would use in the 1/4 mile. Boost would fall off without the nitrous above 4200 rpm all the way down to 12psi at 6000 rpm.

But I would see 17 to 20psi from 3k to 4k.

My car made 340 max rwhp at approx 4200 rpm with the stock ct, them would fall all the way back to 290-300 at 6k.

Don't run a stock motor above 12-14 psi if you want it to last. And don't run your stock ct above 16psi unless you don't care if it blows up. When I was running mine at that level, I did not care what happened, I was out to prove a point and set a record, and it was not to see how long the turbo would last.

 

[IwantMKIII]

^regardless of if you didn't care about the turbo, wouldn't you have run the risk of it blowing in a million pieces and screwing up your engine? Or would most of the pieces get caught by the IC. I have no idea, i've never blown a turbo.

 

[figgie]

Got to love fluid mechanics!!

 

[suprarich]

^regardless of if you didn't care about the turbo, wouldn't you have run the risk of it blowing in a million pieces and screwing up your engine? Or would most of the pieces get caught by the IC. I have no idea, i've never blown a turbo.

I did not care if the motor blew either, when you run your stuff hard, it is not a matter of if. It is a matter of when.

If you blow the turbo, in most cases the motor needs torn down anyway to remove all the turbo bearing material that contaminates the crank and rod bearings.

And lastly, Figgie is pretty much right on the money. Of course we called it Fluid dynamics in my college day. Can't understand why I went through a 5 year Mechanical Engineering degree course just to work on cars....

 

[figgie]

Suprarich

I knew it as fluid dynamics also but they updated the name

 

[MA70witBoost]

Hey Figgie, what would you say that the max reliable psi on a ct26 60-1 with low miles?

 

[suprarich]

Suprarich

I knew it as fluid dynamics also but they updated the name

LOL, well it was a while ago, in fact, we were still using Fortran to program with.


MA70w/B - I would say somewhere around 0 psi. J/K,

 

[zambini]

yeah 60-1 ct26's are notorious for dieing quickly. better to go t4 from what i have read.

 

[tissimo]

60-1 is a large wheel for the small shaft of the ct26, perfect balance is the key to the turbo life with a wheel that large. I would say 17-18 psi ~ the ceiling with a upgraded ct as the turbine speeds are getting up there. You can go higher but the life of the turbo usually suffers.

 

[MA70witBoost]

well i've also been concerned with the effects of cold weather... wouldn't 18psi make 20+ on a cold night?

 

[tissimo]

well i've also been concerned with the effects of cold weather... wouldn't 18psi make 20+ on a cold night?

Thats more of a boost control issues then a turbo issue.

 

[Poodles]

60-1 is a large wheel for the small shaft of the ct26, perfect balance is the key to the turbo life with a wheel that large. I would say 17-18 psi ~ the ceiling with a upgraded ct as the turbine speeds are getting up there. You can go higher but the life of the turbo usually suffers.

Bzzzzt, wrong.

CT shaft is actually larger than the garret shaft (hence why the hole in the wheel has to be enlarged), it's the fact that it's a huge wheel in a small housing that causes surge, surge destroys turbos...

 

[MA70witBoost]

Thats more of a boost control issues then a turbo issue.

no boost controler... shimmed wastegate making 12psi in the summer befor my build (Unleashing The Beast... (56K Beware))

Bzzzzt, wrong.

CT shaft is actually larger than the garret shaft (hence why the hole in the wheel has to be enlarged), it's the fact that it's a huge wheel in a small housing that causes surge, surge destroys turbos...

dont BOV's help this?

 

[tissimo]

Bzzzzt, wrong.

CT shaft is actually larger than the garret shaft (hence why the hole in the wheel has to be enlarged), it's the fact that it's a huge wheel in a small housing that causes surge, surge destroys turbos...

Interesting, always thought the shaft of the turbo was small. But that makes more sense though.


No a BOV does not help as the problem is with the turbo its self, the compressor is outflowing the housing and the causing problems.

 

[MA70witBoost]

so pretty much it means that at some point in my supra's future, imma be swapping out the 60-1 for my spare ct26 if i haven't already upgraded it to a 56trim. I've heard about plain 60 trims and not 60-1's. Heard the 60 Trims are better...

 

[Poodles]

Interesting, always thought the shaft of the turbo was small. But that makes more sense though.


No a BOV does not help as the problem is with the turbo its self, the compressor is outflowing the housing and the causing problems.

Exactly, it's why a lot of modern turbos have ported housings to stop the surge.

IMHO an upgraded CT should be seen as a wear item and treated as such. 57 trim seems to have the best power to longevity balance (as there are smaller trims you can get), going to a 60 or 60-1 (or hell, there is a monster one on ebay all the time) is going to be limited in how long they last, but they might make some nice power...

 

[IwantMKIII]

^from what i've read 60trims are not a big problem, its the 60-1's and larger. They simply outflow the compressor housings.