FML right?

[XoX1de]

How will running high boost on a turbo near redline hurt the turbo?

turbo overspin, exceed rpm limit, and possibly explode... but thats rare, mostly the thrust bearing will give up first.

 

[HondaEat-R]

yes 15psi is no problem from 2500-5000 rpm, hell you can run 20psi on that range, but when u are near redline with that level of boost it will kill the turbo fast. I followed the compressor map to figure it out, so with a boost controller like avcr, you can actunally tune the boost by effency island.

2000rpm 10psi, 3000 25psi 4000 20psi 5000 15psi 6000 8psi, you know what i mean.

I don't run my car even close to redline, ever. As the turbo does nothing good in that range. My car is driven in a manner which showcases only it's strengths...low-mid range torque. "Quickness". I've seen 6k rpm's maybe twice.

 

[Maxx Mazda]

turbo overspin, exceed rpm limit, and possibly explode... but thats rare, mostly the thrust bearing will give up first.

Since when is turbo boost limited by engine RPM? The wastegate will control boost, ergo it controls how fast the turbo is spinning. All the turbo cares about is it's own RPM and boost pressure, it could give a **** what RPM the engine is running at.

Overspinning a turbo (unless it's huge) really isn't possible in the truse sense of the term. Turbos are designed that they will run out of air long before their true maximum RPM is reached. I thin the GT25 is somewhere in the neighborhood of 120,000 RPM, or 2,000 revs per second. I would like to see someone get the GT25 to spin that fast. It's simply going to run so far out of its efficiency range, that it won't happen. In laymans terms, the turbo wont be able to suck in enough air fast enough to create the boost needed by the engine to spin that turbo past that.

When people go outside the efficiency envelope of a given turbo, it's just that. It's going to be putting out air that's so hot that it's not really worth it to run a turbo that small, hence why turbos come in all different sizes. 10psi on a GT25 and 10psi on a GT30 are very different, except when limited by the flow characteristics of the engine itself, but that's a whole 'nuther story...

 

[Maxx Mazda]

I don't run my car even close to redline, ever. As the turbo does nothing good in that range. My car is driven in a manner which showcases only it's strengths...low-mid range torque. "Quickness". I've seen 6k rpm's maybe twice.

That's one of the limitations of the MSP setup, and to some degree the FS engine itself. Do some head work and get that thing breathing, and it will pull right to redline like a bat outta hell.

 

[HondaEat-R]

I'm considering finally doing the 626 mani, just to help a bit up top. I don't think i'll be springing for head-work any time soon, hahah, it'd be nice though.

 

[XoX1de]

Since when is turbo boost limited by engine RPM? The wastegate will control boost, ergo it controls how fast the turbo is spinning. All the turbo cares about is it's own RPM and boost pressure, it could give a **** what RPM the engine is running at.

Overspinning a turbo (unless it's huge) really isn't possible in the truse sense of the term. Turbos are designed that they will run out of air long before their true maximum RPM is reached. I thin the GT25 is somewhere in the neighborhood of 120,000 RPM, or 2,000 revs per second. I would like to see someone get the GT25 to spin that fast. It's simply going to run so far out of its efficiency range, that it won't happen. In laymans terms, the turbo wont be able to suck in enough air fast enough to create the boost needed by the engine to spin that turbo past that.

When people go outside the efficiency envelope of a given turbo, it's just that. It's going to be putting out air that's so hot that it's not really worth it to run a turbo that small, hence why turbos come in all different sizes. 10psi on a GT25 and 10psi on a GT30 are very different, except when limited by the flow characteristics of the engine itself, but that's a whole 'nuther story...

Maybe youre right on the point but its stated on garretts website that running outside of the efficiency zone is hard on thrust bearing and turbo can exceed rpm limit... also I ran 15psi once with gt25, it falls to 12ish psi near redline.

 

[sean22306]

I'm considering finally doing the 626 mani, just to help a bit up top. I don't think i'll be springing for head-work any time soon, hahah, it'd be nice though.

i have parts going up for sale soon to solve your top end problem

 

[HondaEat-R]

i have parts going up for sale soon to solve your top end problem

I'm too cheap, hahhah. Really,