Hks Vpc (vein Pressure Converter)

[Cristian]

http://www.hksusa.com/products/more.asp?id=858

Has anyone used a HKS VPC on their skyline before, or does anyone know much about them?

If click on the link above and read to the end it states that it is used for the factory ECU, does anyone think it will work with a Power FC.

Thanks

Cristian

[paulr33]

my understanding of it is that it uses a map sensor and converts the voltage scaling to airflow voltage scaling to the ecu. are you thinking of using this to give you a gtst djetro setup? makes sense if you are.

whats the reason you want to goto map sensor out of couriosity?

[paulr33]

also discontined so you would have to buy one 2nd hand, should be a few on yahoo auctions

[Cristian]

Thanks for the info.

I want to change because while tuning my air flow meter has been reaching 5065mv @6000rpm in 4th. its close to max and i figured if this works its a beter option then upgrading the airflow metre.

[rob82]

Thanks for the info.

I want to change because while tuning my air flow meter has been reaching 5065mv @6000rpm in 4th. its close to max and i figured if this works its a beter option then upgrading the airflow metre.

<{POST_SNAPBACK}>

Shit mate if your having problems tuning a MAF based PFC then a speed density based system isn't for you.

Edited February 18, 2006 by rob82

[paulr33]

just change to a different airflow

i would suggest

z32 which retains same piping and air filter (80)

or q45 afm which is 90 instead of 80

either will support whatever power you are making if your maxing out the stock one

[Cristian]

The airflow metre is maxed at that voltage. I dont think anyone can tune with the airflow metre after its maxed out

[paulr33]

you can it just means the load axis flatlines and doesn't increase (map sensor style) its fine, and besides it's at 6000rpm anyway so no dramas.

it should also be noted that on the stock r33 airflow meter and default voltage ramp on the powerfc for it it will never drop below load points 14-15 so its no big deal.

[Cristian]

you can it just means the load axis flatlines and doesn't increase (map sensor style) its fine, and besides it's at 6000rpm anyway so no dramas.

it should also be noted that on the stock r33 airflow meter and default voltage ramp on the powerfc for it it will never drop below load points 14-15 so its no big deal.

<{POST_SNAPBACK}>

This is with a stock turbo running 11psi.

I want to upgrade the turbo to a high flow and run around 14psi.

The problem is that the airflow meter wont give a correct A/F reading after the signal voltage is maxed out. The airflow metre wont know how much extra fuel to add in as it cant read the correct airflow reading, which means it will lean out every load point above the maxed load point

[paulr33]

do a map tracer of a 4th gear and watch it drop to about load point 15 and then just flatline. all r33's with pfc and stock afm do this and they are tuned fine. the airflow meter will keep saying 5100mv to the ecu which will correspond to about load point 15, so it will work it means you loose some accuracy as the load axis can't increase anymore. i have seen many r33s on the stock turbo running like this and its fine, besides its just past 6000 so thats not a greal of load points you need then anyway. it wont lean or go bang, you just tune the same, but the load axis wont move anymore, a/f will be fine

next step up is the z32 which will read around 4100mv based on the same load. for a hiflow the z32 is ideal as its a direct swap in pipework size, but you will have to retune the fc once you select the VG30 80 AFM in the AIRFLOW menu and the plug wiring is different also

[paulr33]

what you are seeing is exactly what a map sensor does

once target boost pressure is reached the load axis is the same as the value never changes. in this case it is acceptable and tunability is fine. if you were maxing it out at 2000rpm then it would be sucky, but still tuneable and work OK.

map sensor style is basically that. v8s that run a map sensor also work like this. their only increasing axis on say the 20x20 map is revs as the "load" is fixed by pressure that never changes