OTR CAI tune with stock intake

[moveage]

Hi Dirk!

What does that mean?

 

[Hq King]

You can definitely overthink Cold Air Induction (CAI) on a GenIV. Firstly the purpose is not about (flow) restriction near stock where the factory unit flows 420 CFM.
Actual intake demand depends on quite a few things apart from RPM but bottom line is that with 300° advertised intake you are covered up to max torque (~4500) with stock intake. Taken to 5% redline margin at 100% VE max CFM is less than half that available with most aftermarket CAI -some OTR setups boast 1500+ CFM - totally ridiculous but the whole restriction thing is old school. What becomes important is velocity (air speed) in FPS when you introduce a massive cross section at an early length. Old schoolers just think oversized carb effect.
The centreline length from valve seat to plenum, its volume, through throttle opening area to second harmonic all affect tuning pressures more than oversized air-box and other pre throttle “flow restrictions”.
Ideal is about tuning predictability with reasonably cold air that is not turbulent, not air that changes drastically when idling in crawling traffic vs 125mph down a near freezing drag strip.
Given fixed cross section and runner length the importance of ECU being fed exact mass data for Electronic Throttle Control is far more important than affixing a branded bolt-on, when you don’t factor that by changing relevant parameters (tuning).
Logging MAF data near and beyond max torque is going to inform tuning, including size shape and location of mechanical devices pre TB to maximise velocity (torque) without sacrificing flow at high speed (HP).

So are you are saying cold clean straight air and no more than what is needed , if so now all I need to do is work out how much is enough for . I think you just explained it lol but ???

 

[Ron Burgundy]

What does that mean?

I think they are talking about another member that used to frequent on this forum and has been banned since.
He used to write a lot about tuning etc...although less eloquently and not always right...

 

[RevNev]

Actual intake demand depends on quite a few things

Here's the easy way to test it:
Run the car up on the dyno and graph the power and air/fuel ratio. Remove the air intake from the throttle body and run it up again. Does it lean the air/fuel ratio and make more power? If no, leave the airbox alone it works fine. If yes, try a different airbox or do some airbox/intake mods. You can also datalog the manifold pressure (MAP) to see if it remains at atmospheric pressure at maximum power/RPM. If yes, the manifold/throttle body is well sized for the engine and if not, a restriction exists within the manifold/throttle body. This can change of course with engine mods, camshafts/exhausts etc.

Keeping in mind, the manufacturer isn't as stupid as we think they are. Holden stuff it up with their V6 air box fitted to the LS3 engine then HSV discovers that GM (Chev) got it pretty right with the Camaro (HSV 340) air intake they designed for the LS3 engine. Ultimately, the LS3 should've had the Camaro (HSV 340) air intake as a standard fitment on all VF2 V8's. The colder in the intake charge, the more power potential exists.

The stock ECU won't support much more of a technical approach and will then take a MoTeC M150 ECU where injection timing and lambda trim can be optimised on each individual cylinder in real time.

 

[Ron Burgundy]

Here's the easy way to test it:
Run the car up on the dyno and graph the power and air/fuel ratio. Remove the air intake from the throttle body and run it up again. Does it lean the air/fuel ratio and make more power? If no, leave the airbox alone it works fine. If yes, try a different airbox or do some airbox/intake mods. You can also datalog the manifold pressure (MAP) to see if it remains at atmospheric pressure at maximum power/RPM. If yes, the manifold/throttle body is well sized for the engine and if not, a restriction exists within the manifold/throttle body. This can change of course with engine mods, camshafts/exhausts etc.

Keeping in mind, the manufacturer isn't as stupid as we think they are. Holden stuff it up with their V6 air box fitted to the LS3 engine then HSV discovers that GM (Chev) got it pretty right with the Camaro (HSV 340) air intake they designed for the LS3 engine. Ultimately, the LS3 should've had the Camaro (HSV 340) air intake as a standard fitment on all VF2 V8's. The colder in the intake charge, the more power potential exists.

sv340 airbox picks up the air from the same location as the stock intake duct. as you know it has an additional inlet and slightly larger duct. I think air intake temps would be the same as stock...

The elbow that connects to the throttle body seems much better than the square oem abomination...

 

[moveage]

.

Here's the easy way to test it:
Run the car up on the dyno and graph the power and air/fuel ratio. Remove the air intake from the throttle body and run it up again. Does it lean the air/fuel ratio and make more power? If no, leave the airbox alone it works fine. If yes, try a different airbox or do some airbox/intake mods. You can also datalog the manifold pressure (MAP) to see if it remains at atmospheric pressure at maximum power/RPM. If yes, the manifold/throttle body is well sized for the engine and if not, a restriction exists within the manifold/throttle body. This can change of course with engine mods, camshafts/exhausts etc.

Keeping in mind, the manufacturer isn't as stupid as we think they are. Holden stuff it up with their V6 air box fitted to the LS3 engine then HSV discovers that GM (Chev) got it pretty right with the Camaro (HSV 340) air intake they designed for the LS3 engine. Ultimately, the LS3 should've had the Camaro (HSV 340) air intake as a standard fitment on all VF2 V8's. The colder in the intake charge, the more power potential exists.

The stock ECU won't support much more of a technical approach and will then take a MoTeC M150 ECU where injection timing and lambda trim can be optimised on each individual cylinder in real time.

I’m sure there’s a happy median in there too
My point is what’s outside the TB does matter, two butterfly throttles along the intake to improve torque are definitely a thing, as they are along the exhaust. Is not about flow per sé, rather best cylinder fill / torque.
I looked into the 340 intake when it was released too, still intrigued about the trap door’s control module and harness. A few were looking into PWM / firmware of the bimodal exhaust, was part of the FPCM co-processor under the battery. All became a bit hard in the days before the bimodal exhaust actuator firmware was hacked.
There are CANBUS modules using PWM to control that now according to load / RPM.
It would be for shiz and gigs, a bit of noise control and the under bonnet yarns more than race tech, agreed.

 

[moveage]

sv340 airbox picks up the air from the same location as the stock intake duct. as you know it has an additional inlet and slightly larger duct. I think air intake temps would be the same as stock...

I thought the trap door connected to a fresh air duct in the grille, or was that just in the Camaro?

 

[Ron Burgundy]

I thought the trap door connected to a fresh air duct in the grille, or was that just in the Camaro?

Trap door is not connected to anything...

Just opens up at certain rpm..

 

[moveage]

Trap door is not connected to anything...

Just opens up at certain rpm..

Wonder what this thread was about then?

Bi Modal Air Intake

lol. The Type S was promoted as some secretive exclusive product, and when it was finally revealed... Baaaahahaha!!!

forums.justcommodores.com.au

 

[Hq King]

Trap door is not connected to anything...

Just opens up at certain rpm..

Thought it wasn't just rpm maybe tps or vacuum aswell . Not real sure and as far as the trap door opening I not sure if it would get air from engine bay or maybe wheel arch or some from what doesn't go down snorkel . Which every way it's doesn't look like good air . The 340 snorkel is larger than stock but the fit of snorkel to airbox is poor . The trapdoor does have good line of sight to the filter when opened and as Ron said the elbow looks as though it would flow better. Just my very uneducated thoughts and unfortunately no testing has been done