what psi will ct20 hold at 7K (maxed out!!)

[Fizzy]

as above pls

[^Trickster^]

It should hold around 16psi, but not totally sure if it will hold till 7k, but at roughly that psi your running out of efficency with the turbo anyway as the restrictive exhaust housing just causes a heat buildup resulting in early failure of normally cylinder 3 as this takes most of the heat.

Graeme

[John Rees]

The ct20b will hold 19psi at 7k with no problem, apart from mine which suffered from a bent shaft, although I think this may have been from not letting it cool down enough.

John

[Fizzy]

but my ct26 will hold 1.1 bar to the red !!!!

[^Trickster^]

It might hold it till the red, but you might only be gaining a few extra horsepower and torque for the extremely increased ammounts of heat in turbo backpressure acting on your cylinders and the turbo itself.

The ct20 suffer from weak shafts at the turbine end anyway, boosting 20psi on it wont be doing it any favors either.

The upgraded ct26 i used to have on my car would hold 28psi to redline, but its totally pointless unless i wanted to start frying piston rings.

At 15psi of boost, there is 20psi of backpressure before the turbine wheel, all heat no significant power gain.

Graeme

[Al-sw20]

The ct20b will hold 19psi at 7k with no problem, apart from mine which suffered from a bent shaft, although I think this may have been from not letting it cool down enough.

John

I second that. Did it on sunday. 19psi all the way to redline in 3rd.

[BenF]

It should hold around 16psi, but not totally sure if it will hold till 7k, but at roughly that psi your running out of efficency with the turbo anyway as the restrictive exhaust housing just causes a heat buildup resulting in early failure of normally cylinder 3 as this takes most of the heat.

Graeme

Cylinder 3 runs lean as the intake runner flows more air than the others - its not to do with the turbo housing ..

[^Trickster^]

The stock intake runner is 13% more airflow on cylinder 3 in rev 1 and 2 engines, rev 3 is a more balanced manifold. I was stating that the heat buildup from the turbo causes that cylinder to go first, there are always alot of factors and yes the lean part is one problem, but most stock cars run very rich anyway especially once you have gone past the stock fcd point which is when they injectors go to 100% duty cycle.

The question was about max boost on the turbo, it has already been proven by alot of people that the safest boost level on the stock turbos is around 15-17psi.

Also i have seen one of my own engine damaged by heat buildup from a stock turbo and it was the perfect example of which cylinders get the most heat, 3 was the worst, followed by 4, 2 then 1. the manifold runners are slightly longer as you go along in that order so obviously some run colder/hotter than others and my compression results had proven that, and i know it was heat and notrunning lean as the actually turbo was jammed.

Vauxhall C20LET turbo engines have a similar problem of heat buildup melting piston 3 as the turbo is directly infront on those manifolds and 3 has a very short runner.

Regards

Graeme

[John Rees]

Also i have seen one of my own engine damaged by heat buildup from a stock turbo and it was the perfect example of which cylinders get the most heat, 3 was the worst, followed by 4, 2 then 1. the manifold runners are slightly longer as you go along in that order so obviously some run colder/hotter than others and my compression results had proven that, and i know it was heat and notrunning lean as the actually turbo was jammed.

Answer, get a more efficient direct replacement turbo, Ohh, like mine

John

[^Trickster^]

PE1919 are a good turbo, but i prefer external wategates, I run a TD06 with a 38mm external gate, and it makes decent power with slightly more lag than the ct turbos but unnoticable really.

Graeme

[John Rees]

PE1919 are a good turbo,

Graeme

Cheers dude, yes they are good and alot better than some might think, and you can fit it in 1 day, everything fits straight to it. I'm glad I stayed away from the CT hybrids I can say that for sure and its not that expensive.

John

[Driftlimits Performance]

PE1919 are a good turbo

I been in John 'The road hugger' Rees's 2, and it's fast! And I didn't notice ANY lag! Just loads of explosive power as soon as pedal hits the metal.

[KiwiMR2]

Iv'e been running anywere from 14 psi-22 psi for about a year now. A mate ran 24 psi everyday all day for 2 years. The other Gen III owners I know vary there boost setting as I do......have been for a long time. Al seems to run decent boost quite a bit as well. None of us have blown anything.

Cheers
KiwiMR2

[Al-sw20]

On the street i only run 13psi, on the strip or when ive got avgas left its 18-19psi

[^Trickster^]

Put them on a dyno, see what power increase you make from 17psi then try 20psi, youll find the difference is not much, but watch your egt's go up. Some people can get away with running high boost, its all engine dependant but the fact remains that the physical restraint of the ct turbos is the exhaust housing, and 17psi is about the limit with efficient airflow. I ran 20psi for ages on a stock ct26 with no harm, but i found no power difference when i put it down to 17psi except less heat.

Graeme

[Wobbs]

Hi Guy's
Reading these threads, why hasent anybody mentioned a decent inter cooler. surley its cheeper to get an intercooler than having to re-build your enging????

[^Trickster^]

An intercooler upgraded will lower the intake temperatures but it wont have a noticable effect on egt's at high boost levels on the stock turbo. Water injection reduces the egt's by introducing humidity into the intake charge, but this also takes power away from the combustion so youd have to run higher boost levels to compensate for it, but water injection isnt for that purpose, its for prevention of detonation and to reduce knock.

Graeme

[MR2Mania]

Put them on a dyno, see what power increase you make from 17psi then try 20psi, youll find the difference is not much, but watch your egt's go up. Some people can get away with running high boost, its all engine dependant but the fact remains that the physical restraint of the ct turbos is the exhaust housing, and 17psi is about the limit with efficient airflow. I ran 20psi for ages on a stock ct26 with no harm, but i found no power difference when i put it down to 17psi except less heat.

Graeme

Mate, I think you're talking rubbish!

I was running 19psi on a stock CT20b for ages, no probs with cyl no3 either. Also, it made more power at 19psi than at 17psi. With better intercooling, it could make more power with more boost.

Also, the pressure build up PRE turbo is not a problem unless it's going over 2.5 times the inlet pressure.

You can't compare CT26 exhaust housings to the CT20b ones, because they're different, as is the size of the turbine wheel (smaller on CT20b).

What do you consider high EGTs then?