VF35 "safe boost" threshold. - Page 4 - Perth-WRX.com

dnbosiris · #31 25-06-2015, 10:39 AM

Quote:

Originally Posted by RJ999

What you should really assume is the fact that your tuner's software isn't configured correctly and isn't reading your engine parameters correctly...
...and also sees knock on engines that are running perfectly.

The assumption here is that the tuners software is configured correctly, I've got no reason to believe that's not the case.

RJ999 · #32 25-06-2015, 10:44 AM

Quote:

Originally Posted by dnbosiris

The assumption here is that the tuners software is configured correctly, I've got no reason to believe that's not the case.

reading 24 when pushing 28 psi is a perfect reason.

Jacob92 · #33 25-06-2015, 10:45 AM

Ah which model JDM 207 did you buy? I hope for your sake its a v7 with 2 bar going into it

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dnbosiris · #34 25-06-2015, 10:51 AM

It's a my03 with hypereutectic pistons

Tony · #35 25-06-2015, 10:54 AM

This is literally going to end bad. More boost=more heat. Something you dont want with hyper pistons.

Jacob92 · #36 25-06-2015, 11:03 AM

Tick tock till hole in the block

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Rossco · #37 25-06-2015, 11:26 AM

Quote:

Originally Posted by dnbosiris

Seems most people don't tend to stray above about 1.4/1.5bar on the 207, however theres the odd person running up to 2bar seemingly without issue. I found it very interesting when my tuner said that the much higher boost is safe so long as your afr and timing is safe as well, which I believe it is. I will keep asking around though.

The main reason is that 2 bar for those on 98 means that a lot of timing needs to be pulled (which means lower efficieny & Torque) even on E85 winding in big boost won't net the gains a slightly larger (higher CFM) turbo would with less boost - mainly because the VF turbo is working outside it's efficiency range & adding exponentially more heat to the intake charge v additional boost.

Let's look at flow: A VF35 (420cfm @ 14.7psi) isn't flowing anything like the amount of air a bigger turbo does, ie a Td05-18G flows (585cfm@ 14.7psi).

The main point being the bigger turbo is running in it's proper efficiency range whilst providing more air volume at far lower outlet temps than the VF35 would to produce the same CFM at higher pressure ratio's - which means more timing & more power.

All of the Techy stuff aside, I ran 1.7 bar daily with a VF34 on 98 (and P100) in my 'entry level build' 207 since it was built - it made just over 300hp. Turbo outlet temps would peak at 106 degrees during long pull on boost..... No point in pushing more boost on those temps.