CT26 w/billet compressor boost limit ?? (1 Viewer)

[Drewscruiser]

Hi all.

I have a question for all the turbo gurus out there. I have 1HDT, 3" exhaust with no intercooler as yet. It has a standard CT26 fitted with a KTS billet compressor wheel. The compressor wheel has the same size inducer and exducer as standard but because the billet compressor has a smaller diameter hub, it actually has more blade area. For example; the leading edge of the blades are 2mm larger than the standard compressor wheel. Which my rough calculations gives me aprox 10% - 15% more blade area over the standard compressor. The billet wheel also has 12 blades instead of the 10 blades on the standard compressor.

I have read Graeme's posts in regards to a standard CT26 on a 1HDT has a limit of 14psi with limited rpm over 2500, any higher psi and the compressor speed gets too high and can cause failure.

My question is, given the larger blade area and the extra 2 blades on the KTS compressor, how would that effect the max safe operating psi?

My thoughts are, that at any given psi the KTS compressor wheel would be operating at a lower rpm due to the larger blade area??? therefor I should be able to run slightly higher boost safely??? But would love to hear some thoughts from any turbo gurus out there.

Cheers.

 

[wrongway around]

14 psi limit with limited rpm over 2500 . I saw that as a sales thing.

 

[Drewscruiser]

It may have been a little bit of that ?? but either way it seems to be the general consensus that 14psi would be the maximum boost you would want to run on a standard CT26 and retain long term reliability.

 

[TheBigBoy]

14 psi limit with limited rpm over 2500 . I saw that as a sales thing.

It most certainly is NOT a sales thing. Plenty of broken and destroyed factory CT26's. The same kind of results for "some" highflowed turbo's. Even last weekend a customer came for a tune with a MTQ highflowed "7MGTE" CT26 turbo. He has been running 14psi for a while. They told him it would be fine for 18psi. With in 48hours the seals in the turbo had gone pumping oil straight into his engine and cracked a piston. Others running 16psi have had their compressor wheel smashed to pieces. Its not nice, and not pretty. Neither is the bill to rebuild your engine. So be careful who you listen too.

 

[wrongway around]

Exactly . And you sell who's turbo? I remember when you guys were so anti anything made from Chinese parts. I personally have a couple hundred thousand miles of over 14 psi and defiantly at the top of the food chain in the rpm"s. Never had an issue with 18 psi. But that is only my own personal experience and i don't sell t urbos or hp add ons. I thought everyone was runnning 17-18 psi now.

 

[TheBigBoy]

Read (FACTORY CT26). Not all CT26's are created equal. I would run what ever boost the manufacturer says to run with their reputation on the line.

 

[gerg]

But wrong way your running a totally different turbo right I thought? If it's balanced and has good bearings and isn't overspeeding it should stand up fairly well. I think biggies basically saying if you over speed it, it will die. I agree.

 

[wrongway around]

Yes i have been running a $300 China knock off for two years maybe. But i was running the ct26 in stock form well over 14 for years. I even had a few built up ct26's that were constantly in the high 20 's. Hell look at the g turbo itself i think they can even handle high 20's . All of which are still only a high flowed ct26 .

 

[Tapage]

I don't sell turbos or actually anything .. but in my experience over 14 PSI ( could be 15 or 16 depending on the outside temp and humidity ) you will loose performance beyond that threshold .. then you swap supra CT26 cold side and go adventure to 18 and 20 PSI .. and the same happen this time could be over 16 or 18 PSI ..

all the above it's my own experience and but dyno talking .. so take it in this just dimension ..

 

[Dougal]

It most certainly is NOT a sales thing. Plenty of broken and destroyed factory CT26's. The same kind of results for "some" highflowed turbo's. Even last weekend a customer came for a tune with a MTQ highflowed "7MGTE" CT26 turbo. He has been running 14psi for a while. They told him it would be fine for 18psi. With in 48hours the seals in the turbo had gone pumping oil straight into his engine and cracked a piston. Others running 16psi have had their compressor wheel smashed to pieces. Its not nice, and not pretty. Neither is the bill to rebuild your engine. So be careful who you listen too.

Sounds like something dumped in his engine resulting in high crank-case pressure. Turbo seals are labyrinth type* and only pass oil when the pressure difference across them reverses.

*Yes I know some CT26's run a carbon face seal in the compressor side. But these last longer than 48 hours.

 

[Drewscruiser]

Thanks for your input guys.

Any specific thoughts on the increased blade area and extra 2 blades and how this would effect the safe or efficient operating RPM of the turbo?

I would love to hear Graeme's thoughts on it if you happen to read this.

 

[Dougal]

Thanks for your input guys.

Any specific thoughts on the increased blade area and extra 2 blades and how this would effect the safe or efficient operating RPM of the turbo?

I would love to hear Graeme's thoughts on it if you happen to read this.

Larger intake area makes the turbo capable of more airflow but also less resistant to surge. Whether you can use this extra airflow capacity depends on the match with the engine.

 

[TheBigBoy]

@Dougal, This turbo has been on for almost a year with no issues (to my knowledge) its only when the boost was increased there was a problem. I will find out what actually happened when I strip down the engine.

 

[Dougal]

@Dougal, This turbo has been on for almost a year with no issues (to my knowledge) its only when the boost was increased there was a problem. I will find out what actually happened when I strip down the engine.

Graeme ran "Supra" wheeled CT26's many years ago and to far higher boost. So something else is definitely up. Strip down should be interesting but it can be hard to find the original cause if the mess is big enough.

 

[Crick60]

You guys that boost your CT26's really baffle me, what are you doing that requires more power than standard????

The factory setup power is ample, we don't drive race cars and the drive it like you stole attitude doesn't lend itself to reliability so what's the point?? I can drive my fully laden HJ61 up very steep and long hills between Sydney and Wollongong cruising at 110kph without putting my foot right down and I struggle to come up with any other situation where I would require more power that I would risk the reliability of my 12ht.

 

[Drewscruiser]

You guys that boost your CT26's really baffle me, what are you doing that requires more power than standard????

The factory setup power is ample, we don't drive race cars and the drive it like you stole attitude doesn't lend itself to reliability so what's the point?? I can drive my fully laden HJ61 up very steep and long hills between Sydney and Wollongong cruising at 110kph without putting my foot right down and I struggle to come up with any other situation where I would require more power that I would risk the reliability of my 12ht.

Try towing a 1.5tonne camper through knee deep bulldust or really soft sand, a situation where you really must keep your momentum up, and then you really appreciate the extra torque!

I'm not trying to squeeze every last hp out of it, just sensible improvements and tuning that unlock some of the power that 1HDT's can easily handle.

It all depends what you using it for I guess.

 

[Crick60]

I've towed a shorty up nth point hill at Fraser Island in a hj60 non turbo.
The 1HDT is an excellent motor with excellent power, I don't buy towing a camper through sand or bulldust as a reasonable justification for boosting a turbo especially seeing as places as remote as the Simpson or Kimberly where you experience these conditions are the last places you would want to risk the reliability of your vehicle.

I agree with the idea that there is room to pump up the pressure on a landcruiser turbo as the motors are deliberately over engineered and the turbo adjusted down a little but this is a deliberate decision made by toyota across almost every facet of the landcruiser which is why they have such a legendary reputation for being reliable and why I would never change a thing about them.

Any way sorry I've taken things off topic here.

 

[gbentink]

14 psi limit with limited rpm over 2500 . I saw that as a sales thing.

Because I now sell turbos doesn't mean everthing that I say is laced with sales boosting commentary. People buy my turbos when they want one custom made for their application.

It's easy for anyone to see that your far more slanted than me in your commentary. I think you've spent a year now justifying your purchase.

I have a box of parts on my front office of std turbos that people have run over 14psi because someone said it would be ok etc. they aren't happy people and I don't blame them. Most people aren't hobbiests so they aren't able to cost effectively change a turbo themselves or fix themselves if something goes wrong. So it's irresponsible to mislead people into a false sense of security.

The figures I gave regarding boost, rpm limit (intercooled) were made based on having assurity of reliability. Certainly you can push things and see what happens and sometimes you will be ok.

I don't mind if someone does this as long as the information has been provided so they can assess the risks.

The main reason for the limit in short term use is overspeed. The Billet wheel will give you some headroom in this regard. How much I don't know without doing a simulation. Flow wise the 2mm extra is at the centre of the hub so when you work it out it's prob a 3% improvement. Longer term the issue is oil usage through wear of oil seals caused by thrust bearing wear. So installing a 360 degree thrust at the same time would reduce this.

Have a go if you want to try it. It's not going to be worse than a std turbo.

Oh, Dougal the reason the oil run on issue happens is because the shaft bends, it breaks all the aluminium seal sleeve and since these turbos take unrestricted full oil flow/pressure the oil rushes out.

14 psi limit with limited rpm over 2500 . I saw that as a sales thing.

 

[gbentink]

You guys that boost your CT26's really baffle me, what are you doing that requires more power than standard????

The factory setup power is ample,

Well it's nice that your happy and your lucky because it's a cheaper life for you, but everyone is different.

If you were happy towing with a 2H then your goals are different to many here and that's ok

 

[niffa]

Well said on all fronts graeme