why does boost change so much?

[rug]

Hi,

I have seen some people post on this board that boost fluctuates between 12 and 17 psi for chiped cars. Why is this? What makes the computer change boost that much?

The reson I am asking is because I am thinking of installing an HKS Profec B boost controler (used to have it in my mazda 323 4WD turbo) in my 20VT Cordoba Cupra :) Since this thing would control boost independent from the computer, it would be nice to know why it sometímes increase boost, and sometime lowers it.

Carl

[Crofter]

I was under the impression that such devices wouldn't work with the 20VT due to incompatibility with the ECU etc :(

[m0rk]

Crap software on the original chip.

APR levels it as can Jabbasport chips.

Oettinger, original & (I think) AMD are spikey with the boost levels.

M

Originally posted by rug
boost fluctuates between 12 and 17 psi for chiped cars. Why is this?

[rug]

Crofter> I dont thing it would be a problem since it works independent from the ECU. If you leave the original boost solenoid connected to the ECU it should work fine. The only electronics the HKS unit connects to is 12V power :)

Carl

[ibizacupra]

Originally posted by rug
Crofter> I dont thing it would be a problem since it works independent from the ECU. If you leave the original boost solenoid connected to the ECU it should work fine. The only electronics the HKS unit connects to is 12V power :)

Carl

It will affect the factory ecu as the factory ecu reads actual boost as part of its control. If something else is controlling the boost (like another boost controller) then the factory ecu will try to get to its set point and more than likely get a strop on (technical term :D)

Not saying it can't be done but I doubt its as simple as that.

regards
Bill

[rug]

DOH!

Oh well.. it was a nice thought..

Carl