Custom ATS Placement

[antus]

Actually air temp makes negligible effect on air density for purposes of fuel tuning. Air quantity is relevant but the MAF does handle that and output the correct data. Air temp is needed for spark timing as hot air will detonate sooner. I did think that density made a difference too, but then I did an efi-live tuning course and they set me straight on that.

[MAGP]

Yes I grant that, but accurate air temp (as the engine actually sees it) is required for best tuning. You simply cannot obtain accurate air temp 12" or more away from where the actual tuning matters (in the cylinder).

On a side note have you done any High Performance Academy courses?

[vlad01]

Actually air temp makes negligible effect on air density for purposes of fuel tuning. Air quantity is relevant but the MAF does handle that and output the correct data. Air temp is needed for spark timing as hot air will detonate sooner. I did think that density made a difference too, but then I did an efi-live tuning course and they set me straight on that.

not according to my understanding of physics, air density changes a significant amount.

I found a table here that shows the density.

http://www.engineeringtoolbox.com/air-p ... d_156.html

https://en.wikipedia.org/wiki/Density_o ... d_pressure

In my own cars and the local climate of my area I can see density changes up around 25% based on engine bay air temps on the vp, and maybe around 15% for the vr as it has a CAI., even greater if I base it off MAT temp readings but there is coolant contribution to that.

[immortality]

Just to get this back on track (sort off), this is my setup going on my Senator shortly.

Ultimately, the PCM on a MAF based system is looking for the air temp at the MAF and all tables and hence it's fancy calculations are based on this location just as the Holden MAP based PCM's use a MAT sensor located in the runner just before the head. Why complicate things?

[MAGP]

not according to my understanding of physics, air density changes a significant amount.

Take air speed into consideration, that is why I "agree" with Antus' previous post. Yes air density changes but air speed is high enough to not let it change alot thus the effect on fueling may not be as much as you and I would think.

[MAGP]

Just to get this back on track (sort off), this is my setup going on my Senator shortly.

0-02-01-4b3037d0ae8925d5e77b3f3e768ed35b727c8ccff9563ff5ce206fc0b48c10f2_full.jpg

Ultimately, the PCM on a MAF based system is looking for the air temp at the MAF and all tables and hence it's fancy calculations are based on this location just as the Holden MAP based PCM's use a MAT sensor located in the runner just before the head. Why complicate things?

It doesn't complicate things all that much it just makes the control system work with information from a different location. I have run my VT stroker with and without a MAF, with a 531 and an 808 with and without sequential injection and the net effect of all these differences is the IAT has remained in the stock VT location. When my engine temps are under control I do not personally notice notice a difference in how the engine runs. When engine temps are a bit high (heat soak?) there is a noticeable difference. The MAF style location simply doesn't perform as well as it should in a wide variety of operating conditions.

Just a question for you on your setup, why did you put the sensor on the "slow" side of the inlet tract? If you followed OEM setup you would have put it in the roof of the inlet tract instead.

I like your air bleed system, does it help much on a street engine?

[VK_3800]

Just a question for you on your setup, why did you put the sensor on the "slow" side of the inlet tract? If you followed OEM setup you would have put it in the roof of the inlet tract instead.

That's an interesting question, I did exactly the same with mine simply to keep things neater and never even thought about that. It does appear to respond quickly when the throttle opens though (with the cold air intake it can drop nearly 50 degrees in a second), I guess the reality is that the sensor bulb sits somewhere in the middle of the port either way.

Looks good immortality, would be interested to see a few more details in another thread.

[immortality]

Just a question for you on your setup, why did you put the sensor on the "slow" side of the inlet tract? If you followed OEM setup you would have put it in the roof of the inlet tract instead.

I like your air bleed system, does it help much on a street engine?

I couldn't put it in the factory spot because there was other stuff in the way unfortunately. It went where it went because that is where the drill and tap could fit without to much fucking around, unfortunately not a lot of room on a low rise DP manifold.

Holdens are notorious for blowing head gaskets around the rear cylinder when you start to really lean on it as it runs hotter than all the rest, this solves that problem. Heat soak is a bitch with the standard banana's mani which is why this is going on.

Plan is to get this down to Meremere next year and it may very well cop a decent shot of NOS.......

[MAGP]

Ah ok, I want to swap my manifold but I will do that after the thing gets re-registered. I have to go through a blue slip and possibly engineer again this time around. So I'm interested in different setups people use and how they go.
Cheers.

[vlad01]

not according to my understanding of physics, air density changes a significant amount.

Take air speed into consideration, that is why I "agree" with Antus' previous post. Yes air density changes but air speed is high enough to not let it change alot thus the effect on fueling may not be as much as you and I would think.

Can you show the equations and your workings?