Hypothetical Small Turbo VS Larger

[Mike T]

hard to say,here is a bad scenerio.large turbo/low backpressure small rpm window,so when your trying to push boost your not getting it till its too late or it wont make it to the higher number.the aero is so much better on the new stuff it moves the air with less.in your case i would try and turn it up before i switched the turbo,see what it makes and go from there.

Each of your replies have provided additional food for thought. My instincts are that the motor is going to react in a positive way to more rpm.

 

[bison]

you said 20 psi across the board from start to finish ...60 vs 70 .. volume plays into it

Since boost is restriction would we need to see RPM increase for volume to increase?

Exactly. What if the converter was a little looser and the valvetrain could handle the additional rpm? I’d bet that 70GTQ would walk all over just about anything. It’s been 9.0 iirc.


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[Mike T]

Exactly. What if the converter was a little looser and the valvetrain could handle the additional rpm? I’d bet that 70GTQ would walk all over just about anything. It’s been 9.0 iirc.


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I have looked everywhere for a GTQ 70 compressor map. Any idea where I could find one?

 

[TTipe]

This has digressed. The solution is whatever turbo allows you to pack the most molecules (air mass) into a unit volume while wheel rpm is at the high end of the compressor wheel efficiency island. This only applies to the turbo itself less any external influences. If we bring in external influences (ie drive pressure,back pressure, ambient air air temperature, A/R, etc.) there is no way to use a fact as a common understanding without a large amount of noise.

 

[Mike T]

This has digressed. The solution is whatever turbo allows you to pack the most molecules (air mass) into a unit volume while wheel rpm is at the high end of the compressor wheel efficiency island. This only applies to the turbo itself less any external influences. If we bring in external influences (ie drive pressure,back pressure, ambient air air temperature, A/R, etc.) there is no way to use a fact as a common understanding without a large amount of noise.

Yes a little. Compressor map was for personal use.

 

[Jerryl]

I have looked everywhere for a GTQ 70 compressor map. Any idea where I could find one?

I think this might be it:
http://turbocharged.com/catalog/compmaps/t70.html

 

[Mr.Spool]

My instincts are that the motor is going to react in a positive way to more rpm.

then hang on

 

[Mike T]

This has digressed. The solution is whatever turbo allows you to pack the most molecules (air mass) into a unit volume while wheel rpm is at the high end of the compressor wheel efficiency island. This only applies to the turbo itself less any external influences. If we bring in external influences (ie drive pressure,back pressure, ambient air air temperature, A/R, etc.) there is no way to use a fact as a common understanding without a large amount of noise.

It didn't hit me until rereading your post. I got too focused on explaining why I was asking for a compressor map and missed the bigger message.

Your post is exactly on point given the guidelines provided. It is important to keep it basic so we can all participate. It is also nice when someone can explain the physics behind the subject as well.

 

[TTipe]

Thanks for the positive response These cars can be made remarkable with the proper adjustments. Look at what the "cats' turn. There are turbo regals that run with them/ better.

 

[turbo89]

Exactly. What if the converter was a little looser and the valvetrain could handle the additional rpm? I’d bet that 70GTQ would walk all over just about anything. It’s been 9.0 iirc.


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For the OP's Scenario .. just as he posted it ... with the criteria he outlined ... the 70 will outrun the 60 it's simple

and I have witnessed this on a specific car that was "UNDER Turbo'd" some of the responses here are looking further into things than what were posted ... if we change other criteria or the scenario.. results would be different

 

[bison]

Exactly. What if the converter was a little looser and the valvetrain could handle the additional rpm? I’d bet that 70GTQ would walk all over just about anything. It’s been 9.0 iirc.


Sent from my iPhone using Tapatalk

For the OP's Scenario .. just as he posted it ... with the criteria he outlined ... the 70 will outrun the 60 it's simple

and I have witnessed this on a specific car that was "UNDER Turbo'd" some of the responses here are looking further into things than what were posted ... if we change other criteria or the scenario.. results would be different

its not that simple. If it was running on a stock engine/config it most likely wouldn’t.




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