20 bhp increase offered on e-bay

Seen this?

http://cgi.ebay.co.uk/ws/eBayISAPI.d...485674228&rd=1

20bhp increase. Fools the ecu into thinking that the intake air temp is lower, therefore more power...all for a fiver (ath the moment!)

[Phil Hill]

Only £4.95, that's a mighty expensive resistor !!

I've been avoiding commenting on these things on various Mini boards, but anyway.......... here goes !!

As far as I can make out this is something like a resistor which is connected in-line with either the air flow sensor or the engine temp sensor.

This "fools" the ECU into thinking either the intake air is colder (i.e. denser) than it is, or the engine is colder than it is, which changes the amount of fuel injected. In this way you get more fuel for your current engine conditions.

If the "adaptive" bit of the ECU is any good, when you are in "closed loop" (i.e. crusing) the Lambda feedback will tell the ECU to lean off the fuel which has been artifically increased by the "lieing" sensor. In this way you *shouldn't* see an increase in overall fuel consumption.

When you are "clogging on" you are now running "open loop", and the fuel table will be offset by the "lieing" sensor, so the ECU will put more fuel in. Hopefully the ignition control will do it's bit as well and advance/retard accordingly.

So that's the basics of it. In theory it could and even should work.

But does it actually work ?? I don't know, I've never done it.
Are the testimonials credable ?? I don't know, they look good but let me explain a bit about chassis dynos/rolling roads.

A chassis dyno or rolling road is a measuring device. It is only as useful as the operator using it, the calibration of equipment, and the corrections used on the figures gained from it.

Unless these figures presented were recorded under the *exact* same conditions of ambient temp, barometric pressure, relative humidity, altitude etc or the figures were corrected back to standard ISO day, you cannot directly compare the figures. We assume these figures were all recorded on the same day at the same location on the same dyno, but we don't know anything about the other conditions. We don't know if there were any other works carried out on the vehicles at the same time (new filters, plugs, etc). We don't know if the vehicles were initially tested stinking hot having driven to the dyno, then allowed to cool while the "chip" was installed, then re-dyno'd. These gains are really small, and could easily be "fudged" by a dyno operator.

Now I'm not saying the claims are incorrect, I'm just saying I'm sceptical. I would have to see them myself under my conditions.

Let me put it to you another way, I can get you another 5-10 bhp on a chassis dyno by increasing the tyre pressure by 10psi..........

[b3lha]

This device has been discussed before on other sections of the site.

I think that if Subaru could have added for negligable cost they would have done so at the factory. The factory setup is probably as good as you can get without spending a lot of cash.

Phil.