edited

 

Why do you correlate 180 load to be 13psi?

Load will always taper as rpms increase (since boost is tapering off).

 

All things being equal - if the above is true - say you have some abnormal boost drop off towards redline - can you use this calculated load value to verify boost drop off?

For intsance - if you're tapering to an abnormally low 15pis - will the calculated load value be low as well?

 

I don't know if anyone has ever tried to correlate load back to boost. They are definitely directly proportional, but I don't think it's an accurate way to measure boost. If you see a large dropoff of load, you probably have a large dropoff of boost, but the only way to know if it's 'abnormal' would probably be to have an actual gauge.

 

noooo i run 25 pounds flat out till redline and my load tapers down about 60 points or so also, do not try to guess boost from load, if you are on the stock turbo then you taper down to 18 or so just like everyone else

 

That's correct. Boost is not proportional to load. Load is more directly proportional to a mass airflow/revolution, like g/rev.

The reason why load isn't proportional to boost is because volumetric efficiency drops off at increasing RPMs.


Eric

 

edited

 

Load is a factor of Volumetric efficiency.. Boost is only a component of VE and therefore doesn't really correlate to load the way you'd expect.

 

Don't lots of turbo timers have boost gauges of sorts built in?

 

Are you getting any knock? Maybe you are knocking in the higher RPM's causing your timing to retard (and consequently taper the load down).

 

I don't have the link, but I posted a graph on here of my calculated load against the JDM 3 bar MAP sensor. There was the expected divergence at high RPM from reducing VE.

 

no knock at all.

 

THATS NOT THE PROBLEM AS WE SAID BEFORE, i dont think you have any problems unless you feel as tho you are low on power or something, if not don't worry about CACULATED, or guessed, or estimated, not for sure, load

 

How do most people tune their AF then?
I tune my other car with a speed density setup.
So I tune everything over atmospheric pressure at 11.5. It's very simple and easy for me to do.

On this car, since load isn't directly related to boost...at what load do you want to hit your specific AF's at?

Or should I just guess a nice one (11.5) , and then start playing with timing until knock?

My original plans were to tune everything above 100 load value to 11.5 and then start playing with timing.

But I'm not so sure that is the best way about it.
Do people taper their AFR's richer as load increases?
Suggestions?

 

It is very possible to do this as long as there is no mods that change Volumetiric efficiency, i.e. cams or strokers