Better turbo or bigger IC? Help me decide

[GreddyMR2]

Hi,

Firstly what I have and what is the problem.

I have a hybrid CT20 turbo which has bigger compressor wheel and stock exhaust side. Also I have ARC side mount intercooler.

The problem is with my IATs. They are extremely high. When boosting from 2nd to 5th gear, IAT raised to 90 deg celsius! We played with a timing, but it didn't help a lot. Managed to lower it to ~75. When cruising, IATs are good, around 25 deg...

I am using my car mainly only for track so it's not acceptable to have such temps.

What do you think, boot mount IC would help to lower temps or do I need to change a turbo? I decided to go for boot mount, not for charge cooler or meth injection because of price and complicated installation.

I am wondering that if this turbo blows only hot air, then maybe IC won't help in this situation? Do stock CT20 turbos blow such hot air on constant boost?

I am quite happy with performance, but not happy with IAT so now wondering what to do.

Apprieciate all for your help!

[2mad]

Not being funny are you 100% sure thats the numbers .. i got 50c full boost full tilt on an ebay intercooler ... w/m got me 25c or less

[GreddyMR2]

Not being funny are you 100% sure thats the numbers .. i got 50c full boost full tilt on an ebay intercooler ... w/m got me 25c or less

At least my MAT sensor is faulty, but I doubt it... It's new.

But I would be happy that it's faulty and shows silly numbers But it shows ok at idling or cruising.

Which turbo do you have?

[2mad]

90 deg celsius is really high .. i've done loads of data collection on both my mr2 and gt4 ... 50c is the average full boost number when going for it .



CT20B on both mate

[GreddyMR2]

90 deg celsius is really high .. i've done loads of data collection on both my mr2 and gt4 ... 50c is the average full boost number when going for it .



CT20B on both mate

OK, interesting. What boost were you running?

[2mad]

1.1 bar mate .. 50c+ after 3 pulls .. very reliable air charge temperature gauge


Taken from the manifold .. runner one

[GreddyMR2]

1.1 bar mate .. 50c+ after 3 pulls .. very reliable air charge temperature gauge


Taken from the manifold .. runner one

I am wondering if CT20 with a bigger compressor wheel could cause such increase in temp.
I thought maybe IAT sensor needs to be calibrated, so will check for this.

[2mad]

1.1 bar mate .. 50c+ after 3 pulls .. very reliable air charge temperature gauge


Taken from the manifold .. runner one

I am wondering if CT20 with a bigger compressor wheel could cause such increase in temp.

From my experience over 11 years "nope" the less work it has to do the colder charge it will push

[2mad]

If you have a leak it (the turbo) will push harder (hotter)

[GreddyMR2]

If you have a leak it (the turbo) will push harder (hotter)

Surfaces are clean and all new genuine gaskets, so I doubt there are any leaks. Also new manifold and turbo bolts and nuts are all new.

However after this weekend's race event some of the exhaust gasket blown, but it's probably turbo - downpipe gasket as performance did not suffer.

[2mad]

Somethings a miss .. 90c is crazzy high

[GreddyMR2]

1.1 bar mate .. 50c+ after 3 pulls .. very reliable air charge temperature gauge


Taken from the manifold .. runner one

I am wondering if CT20 with a bigger compressor wheel could cause such increase in temp.

From my experience over 11 years "nope" the less work it has to do the colder charge it will push

My guess is that exhaust side is now too small and there is not enought flow tfor hot gases to exit and they come back to engine. Is that possible? The turbo is also creeping.

[2mad]

Doubt it .. 90c is a mega and i mean mega high number greddy ..

As for creep .. port it .. you running the turbo i sold .

[C35Rob]

I am wondering if CT20 with a bigger compressor wheel could cause such increase in temp.

From my experience over 11 years "nope" the less work it has to do the colder charge it will push

My guess is that exhaust side is now too small and there is not enought flow tfor hot gases to exit and they come back to engine. Is that possible? The turbo is also creeping.

kind of, there will be pressure in the exhaust manifold that is relative to the boost pressure you run, a bigger turbine housing will help to reduce this somewhat but the effect of the increased pressure would be increased cylinder temps, not IAT

having a bigger compressor wheel should lower IAT, assuming the same boost pressure. assuming you're on the standard IWG, the bigger compressor wheel will be contributing to the boost creep. what downpipe do you have? if it's a cheapo xspower/ebay one then that will also be a factor as they're pretty crap.

90 degrees is mega high though, I'd re-check preferably with a different/known good sensor before doing anything else.

[GreddyMR2]

From my experience over 11 years "nope" the less work it has to do the colder charge it will push

My guess is that exhaust side is now too small and there is not enought flow tfor hot gases to exit and they come back to engine. Is that possible? The turbo is also creeping.

kind of, there will be pressure in the exhaust manifold that is relative to the boost pressure you run, a bigger turbine housing will help to reduce this somewhat but the effect of the increased pressure would be increased cylinder temps, not IAT

having a bigger compressor wheel should lower IAT, assuming the same boost pressure. assuming you're on the standard IWG, the bigger compressor wheel will be contributing to the boost creep. what downpipe do you have? if it's a cheapo xspower/ebay one then that will also be a factor as they're pretty crap.

90 degrees is mega high though, I'd re-check preferably with a different/known good sensor before doing anything else.

Thanks a lot for your answer!
I have cheap downpipe I assume, but never had problems with boost creep when I had stock CT26 turbo. So I assume it's working fine.

I just found the tech sheet of my IAT sensor and made adjustments in ECU file.

Here is how this table looked before and after calibration.
Maybe this was the problem? You can see in "before" picture, that line chage its direction at 40 deg. celcius. And we noticed that temp was increasing slowly up to 40deg and then started to increase very fast from that point.

Also, I will try to fit thermometer from electronics shop and will see what it will show

BEFORE


AFTER

[C35Rob]

that's the difference between berk and the cheap ones... restrictive at best, some are bad enough that the wastegate flapper hits them.

[GreddyMR2]

Image Replaced With URL For Quote

that's the difference between berk and the cheap ones... restrictive at best, some are bad enough that the wastegate flapper hits them.

But I think WG is supposed to hit DP? It hits stock DP as I saw marks on it. I had a DP that was fat like Berk and WG was not hitting it and so it opened too much and stuck open.

[C35Rob]

Image Replaced With URL For Quote

that's the difference between berk and the cheap ones... restrictive at best, some are bad enough that the wastegate flapper hits them.

But I think WG is supposed to hit DP? It hits stock DP as I saw marks on it. I had a DP that was fat like Berk and WG was not hitting it and so it opened too much and stuck open.

wastegate valve is not supposed to hit the dp

[GreddyMR2]

Image Replaced With URL For Quote

that's the difference between berk and the cheap ones... restrictive at best, some are bad enough that the wastegate flapper hits them.

But I think WG is supposed to hit DP? It hits stock DP as I saw marks on it. I had a DP that was fat like Berk and WG was not hitting it and so it opened too much and stuck open.

wastegate valve is not supposed to hit the dp

So why it was sticking open when I had another DP? It opened to much and did not close.

[C35Rob]

But I think WG is supposed to hit DP? It hits stock DP as I saw marks on it. I had a DP that was fat like Berk and WG was not hitting it and so it opened too much and stuck open.

wastegate valve is not supposed to hit the dp

So why it was sticking open when I had another DP? It opened to much and did not close.

possibly a faulty actuator and/or incorrect rod length - the spring should pull it shut, if the arm goes "over centre" then it would stick