CT20 turbo overboost Options

[Island_Racer]

How capable are these turbos at surviving pressure above 18psi. Ive heard "hot air" etc...but i have a water injection system....i can clamp the signal and tune beyond the 18psi fuel cut but what other than hot air should i be concerned about? and do you think the water injection can cover that?

[Smaay]

wont make a difference. you are out of the efficiency range of the turbo.

[Island_Racer]

wont make a difference. you are out of the efficiency range of the turbo.

I thought that as well, however i was tuning on the weekend and did a run at 16 psi...made 290whp....when I did my last run however i took off the air filter and in my run the car went to 21psi (filter was blocked up) i lifted off the accelerator when i noticed we hit 21psi but when we looked at the dyno sheet it was at 310 just before i came off....there was way more rev to get (i lifted as soon as i noticed the 21psi).

This is why i ask...because im intrigued by what happened....can you explain that....i havent found a compressor map for the ct20...if you have one can you post it for me?
Id love to do this again and have more to say, but i just wanna know if the turbo is structurally capable of maintaining 20psi....

This post has been edited by Island_Racer: Mar 25, 2015 - 11:59 AM

[Smaay]

sure the turbo had less restriction allowing for more boost to be made, however at 20psi the turbo isnt efficient. Like you said in the first post, its just pushing hot air. I cant think of a metaphor to relate it to.

lets say you take 10psi through a small turbo its moving X amount of CFM. then you install a large turbo and boost the same 10psi. its going to be moving Y amount CFM. another example is water flowing through a straw and a garden hose. both at 10spi but the hose is moving much more volume. So when you beyond the efficiency range. its the same amount of volume in the garden hose but now its flowing through a larger pipe. there is wasted air in that volume.

[Island_Racer]

sure the turbo had less restriction allowing for more boost to be made, however at 20psi the turbo isnt efficient. Like you said in the first post, its just pushing hot air. I cant think of a metaphor to relate it to.

lets say you take 10psi through a small turbo its moving X amount of CFM. then you install a large turbo and boost the same 10psi. its going to be moving Y amount CFM. another example is water flowing through a straw and a garden hose. both at 10spi but the hose is moving much more volume. So when you beyond the efficiency range. its the same amount of volume in the garden hose but now its flowing through a larger pipe. there is wasted air in that volume.

I think youve gotten a little confused about what I'm saying man. Im asking....can the ct20 turbo actually hold 20 psi for extended periods...i understand that it wont stand in any of the efficiency islands...but will it surge or choke at 20.....and can i use the water injection system to bring the air temps back down. If you look at the parts list for my car, u'll see the only thing left to do is buy a larger turbo (just wanted to push this one really really far...just to see what it does)

I know i could very easily buy a gt30 or t series, run 16psi on that and make way more power....but im just choosing to use the ct20 out of curiousity...

This post has been edited by Island_Racer: Mar 25, 2015 - 1:55 PM

[3WayStunna]

sure the turbo had less restriction allowing for more boost to be made, however at 20psi the turbo isnt efficient. Like you said in the first post, its just pushing hot air. I cant think of a metaphor to relate it to.

lets say you take 10psi through a small turbo its moving X amount of CFM. then you install a large turbo and boost the same 10psi. its going to be moving Y amount CFM. another example is water flowing through a straw and a garden hose. both at 10spi but the hose is moving much more volume. So when you beyond the efficiency range. its the same amount of volume in the garden hose but now its flowing through a larger pipe. there is wasted air in that volume.

I think youve gotten a little confused about what I'm saying man. Im asking....can the ct20 turbo actually hold 20 psi for extended periods...i understand that it wont stand in any of the efficiency islands...but will it surge or choke at 20.....and can i use the water injection system to bring the air temps back down. If you look at the parts list for my car, u'll see the only thing left to do is buy a larger turbo (just wanted to push this one really really far...just to see what it does)

I know i could very easily buy a gt30 or t series, run 16psi on that and make way more power....but im just choosing to use the ct20 out of curiousity...

Sure you could do it and it would work swimmingly. But why? Just because you can do it, does not mean it makes sense to do it. Reason being is that you just aren't making any more power to risk running your turbo like that. You are better off getting the Gt series turbo and pressing on from there.

[lagos]

People have installed helper springs on the waste gate to allow the turbo to hold high boost like that, so technically you can do it.
The only problem is that this is a bit too much for pump gas and the stock timing map to handle. You can add methanol injection, but you might need more of it than you realize to combat detonation at that boost level.
To do this safely, you would need something like a J&S Safeguard to monitor knock as you experiment with boost and methanol amounts.

[Island_Racer]

sure the turbo had less restriction allowing for more boost to be made, however at 20psi the turbo isnt efficient. Like you said in the first post, its just pushing hot air. I cant think of a metaphor to relate it to.

lets say you take 10psi through a small turbo its moving X amount of CFM. then you install a large turbo and boost the same 10psi. its going to be moving Y amount CFM. another example is water flowing through a straw and a garden hose. both at 10spi but the hose is moving much more volume. So when you beyond the efficiency range. its the same amount of volume in the garden hose but now its flowing through a larger pipe. there is wasted air in that volume.

I think youve gotten a little confused about what I'm saying man. Im asking....can the ct20 turbo actually hold 20 psi for extended periods...i understand that it wont stand in any of the efficiency islands...but will it surge or choke at 20.....and can i use the water injection system to bring the air temps back down. If you look at the parts list for my car, u'll see the only thing left to do is buy a larger turbo (just wanted to push this one really really far...just to see what it does)

I know i could very easily buy a gt30 or t series, run 16psi on that and make way more power....but im just choosing to use the ct20 out of curiousity...

Sure you could do it and it would work swimmingly. But why? Just because you can do it, does not mean it makes sense to do it. Reason being is that you just aren't making any more power to risk running your turbo like that. You are better off getting the Gt series turbo and pressing on from there.

O yeah man, i have intentions at some point of going to a more capable turbo....like i said, i just happened to accidentally boost to 21psi on the dyno one day and saw that at like 4900 rpm the engine produced 315whp (graph fell off because i stopped accelerating when i saw the 21psi) which is like 30whp more than what i usually make at 16-17psi ...am i wrong to just be curious how much it wud happen to make if i fulfilled the conditions to prevent knock (especially since i have meth injection)...not saying i wanna run that as a daily setup...just wanna kno if the bearings, turbine wheel, shaft etc will survive a pull or two to 7000rpms at that boost....

This post has been edited by Island_Racer: Mar 26, 2015 - 11:04 AM

[lagos]

Island Racer, this has already been done.
http://www.6gc.net/forums/index.php?showto...39452&st=20

[Island_Racer]

Island Racer, this has already been done.
http://www.6gc.net/forums/index.php?showto...39452&st=20

you sir, are a great help...Jim seems to have done what i was curious was possible....im just curious now how long his turbo lasted....

one other thing....its kinda interesting that "Jim" made 330whp @ 21psi using the ct20 while "cuts the pilot" two charts after made 355whp @ 22psi using a gt30...id have thought it would have made a bit more at that at that amount of boost......i can imagine though his turbo was prolly just yawning compared to the ct that prolly having close to a heart attack....lol

This post has been edited by Island_Racer: Mar 27, 2015 - 12:01 PM

[lagos]

Island Racer, this has already been done.
http://www.6gc.net/forums/index.php?showto...39452&st=20

you sir, are a great help...Jim seems to have done what i was curious was possible....im just curious now how long his turbo lasted....

one other thing....its kinda interesting that "Jim" made 330whp @ 21psi using the ct20 while "cuts the pilot" two charts after made 355whp @ 22psi using a gt30...id have thought it would have made a bit more at that at that amount of boost......i can imagine though his turbo was prolly just yawning compared to the ct that prolly having close to a heart attack....lol

And Batman made 329hp at 19psi.

Tuning the ignition timing map has a lot to do with how much power is made. Cuts The Pilot is running an aftermarket ECU that is not properly tuned.