So how would that work?

I'd like to know because as I said, i'm just trying to use my common sense.......

Thanks,

Tony

 

It doesn't matter whether the MAF is before or after the turbo. It meters how much air the motor is using, which tends to go up with any mod that increases flow (more boost, bigger cams, larger turbo, etc.). What I don't know for sure is whether tuning has a significant impact on the air consumed by the motor, or whether tuning just makes the motor use that air more efficiently to generate power.

Where is the little hammer and red box with the glass cover so we can get an EvoM Guru in here to comment

 

The turbo compressor has an inducer, which draws air into it, and the exducer, which blows the air out of the turbo. What goes in must come out. Its those stupid laws of thermodynamics at work .

I do find it odd that EVO8LTW had no change in the MAF readings.

 

any 425 + dyno runs yet?

 

My best guess is that this turbo shines above 21 psi where the stock turbo runs out of breath. The dyno graphs that were posted by Switzer were at 23 psi. I'm only running ~20 psi for now until I get it tuned. Seems like this could have implications for those who plan to run only 91 octane.

 

Or it could just be that the MAF is maxed out, what voltage is it reading?

 

Not even close. The peak airflow numbers that I saw were around 1780 or so. The MAF is good up to 2400+. Not sure what units those are...whatever the UTEC spits out.

 

I don't have time to be long winded right now, but my car fell on it's face trying to run it conservatively on the OE turbo tune. After some ADDED timing and fuel, it came alive at anything over 3000rpm... I get tuned Saturday, and re-dyno'd where I last dyno'd on the 17th...

 

Those MAF numbers of 1780, the units are Hz (hertz). That is the output from a Karman Vortex meter. You are seeing 1780 Hz at 21 psi. I see about 1920 hz at 21 psi with the stock TME turbo. However the MAF readings do vary depending on which air filter that you have. Some Air filters cause the readings to be higher than others, that is why you need to tune you car when you put on an intake.

If you are only flowing 1780 hz, then you dont have a boost leak. If you had a boost leak and running 21 psi, the MAF readings would be higher. The turbo would be sucking in more air than the intake manifold pressure would be showing. It doesnt sound like you have a boost leak to me.

Brian

 

What is your boost tapper looking like? I'm thinking I have a tiny leak as I peak at 23 then tapper down to 19.

 

Please keep us posted Zeus.

 

The MAF readings will not be significantly different at the same boost levels. For x amount of boost and y amount of RPM the MAF will see the same basic values if given the same psi from the turbo. You would have to have a LOT larger turbo moving a LOT more air to even begin to see a difference, the engines Ve dictates this. Where the turbo will begin to shine is at higher rpm's where it will be able to sustain a given boost value at a higher rpm, this is where the MAF values will differ. Just get it tuned, then make a judgement. I truley believe that this will be a hell of a responsive, higher flowing, ideal street turbo, I would have gone with a GT30 if I thought that it would be a better street turbo. I do however think that my 2.3 rabbit will pull like a big block once tuned though!

 

I am seeing about the same taper as with the stock turbo -- around 1 psi or less (I have MAP sensor datalogs), but I don't have my boost turned up as much as you do (yet).

 

how high can you boost with the WR on 93 octane?

 

This is a bit offtopic so I'm reluctant to make a very technical post.. But I wanted to point out that two turbos at the same pressure, can indeed have different MAF readings, given one is more efficient than the other at that pressure, then the air density would be higher, and that should result in the slightly higher reading.

I suspect at 19-21psi, the stock turbo is at the tail-end of its efficiency window, and the white rabbit is just getting into its window, so given that overlap, its likely the numbers would be the same in that range. Where the WR would shine is beyond that point where it can still provide a decent cooler/denser air charge at higher boost levels, and maintain that level of pressure through a higher RPM, so at readline at higher boost, you'd probably see MAF readings over 2000hz where you might see a max of 1990hz or so on a stock turbo (I've seen over 2000hz but not by much)

I'm by no means a thermodynamics or fluid dynamics expert, so I can't argue too much about what or why this works the way it does, but there are some obvious differences between the two compressor wheels which would indicate to me its efficiencies are at different points.