VF HSV airbox ? Whats the deal ?

[Ron Burgundy]

hmmmm.....
Andrew Purcell got John Mazarakis. “HSV Technical Advisor' at the HSV drive day
I attended in 2015 to explain this.
Drive by noise was not the issue like it is with carby engines, closing the bimodal air
intake to slow air intake speed was needed to boost low engine speed torque* was
the reason given

*always an issue since LS1 powertrains were released here

That was my understanding as well. I don't think that stock SS airbox is restrictive anyway with stock tune. The email was from Andrew

 

[07GTS]

some of the US LS's had variable intake manifold runners, which is why in the tune files we have fueling tables for manifold open, manifold closed

 

[RevNev]

hmmmm.....
Andrew Purcell got John Mazarakis. “HSV Technical Advisor' at the HSV drive day
I attended in 2015 to explain this.
Drive by noise was not the issue like it is with carby engines, closing the bimodal air
intake to slow air intake speed was needed to boost low engine speed torque* was
the reason given

*always an issue since LS1 powertrains were released here

That's nonsense!

The engine isn't drawing enough air at low RPM for the airbox intake size to do anything. Better question, why does the LSA engine have the same bimodal air intake with forced induction?

It'll be intake noise exceeding the decibel meter guaranteed!

 

[Ron Burgundy]

That's nonsense!

The engine isn't drawing enough air at low RPM for the airbox intake size to do anything. Better question, why does the LSA engine have the same bimodal air intake with forced induction?

It'll be intake noise exceeding the decibel meter guaranteed!

If that's the case why did they bother with it anyway ?

Slightly more air at higher rpm ?

 

[RevNev]

If that's the case why did they bother with it anyway ?

Slightly more air at higher rpm ?

The 340 intake tube is from the Camaro adapted to fit the Holden airbox top. The stock airbox intake probably is restrictive at higher RPM with the bimodal intake valve when open making more top end power.

I've got the 340 airbox on my Redline ute with the bimodal valve removed, but I didn't run it on the dyno to see a power gain.

 

[RevNev]

Ron, here's the Camaro air box and the intake looks pretty small compared with the bimodal. The Camaro airbox may be a little bigger looking at the picture.

 

[Ron Burgundy]

Ron, here's the Camaro air box and the intake looks pretty small compared with the bimodal. The Camaro airbox may be a little bigger looking at the picture.

View attachment 266529

Yeah, I see. The inlet on that airbox does look quite small. I wonder if the airflow was an issue why HSV did not go with better flowing air filter as they later did with GTSR. I am guessing the development of bimodal intake with all modules, etc, would cost a bit to develop

 

[RevNev]

Yeah, I see. The inlet on that airbox does look quite small. I wonder if the airflow was an issue why HSV did not go with better flowing air filter as they later did with GTSR. I am guessing the development of bimodal intake with all modules, etc, would cost a bit to develop

There was a bit of development with the bimodal intake controlled by the HSV EDI module or without the EDI option in the last MY16 340's, they had a bimodal intake control module.

The 340 was over by the time the GTSR was released with a better air filter, but the GTSR air filter could improve the 340 setup. Quite a few claimed a K&N filter fitted to the 340 airbox made more power.

 

[Ron Burgundy]

I find it very interesting how many hoops they need to jump through to satisfy noise/emission regulations. In reality it's all pointless as most people rip stock setup out and go with OTR and tune. Anyway...

 

[Ron Burgundy]

A bit more info

So basically, some extra air for peak power when open, but closed position was really about the noise...