Thanks for the reply.

Does this HKS AFR module have a bypass switch? I could then leave the unit off normally but switch it on if i'm going for a blast!

Gethin,

I have utilised an HKS AFR - it is looped into the AFM circuit and needs a 12v supply. Maximum improvement, I believe is 1% extra fuel. Typically you utilise +3 (0.6%) increments as more causes flat spots.

I have actually discarded my AFR as it was causing corruption of the AFM reading - almost certainly because it was faulty.

In answer to you questions - if the AFR is located sensibly you can get easy access to it in the passenger footwell - where you can increase/decrease increments with a small screwdriver - including setting it to zero.

The HKS item is very basic and increases fuel right across the range. MRT/Training WRX describe a number of units that manage fueling according to engine needs, linked to Boost/Lambda/Temperature sensors - these cost around A$6-900 and like Mark says will need carefull setting up.

An alternative path would be to go the whole hog and get something like Possum LINK.

There is one STi V with Possum LINK fitted and apparently is running very well - nice grey exhaust - not black and sooty - and very smooth across the range.

I am not convinced that the AFR did much for my car - even when it was working! It is a crude tool to a bigger problem.

Cheers,

David...

...man with very lean running car :-(

After my visit to PE on Saturday, and after a chat with the guys there, I am considering fitting the HKS AFR module to increase the fuelling at the top end of my range as the car is running lean which will cause me problems if pushed hard.

The car was lean before at 289/234 but as it's now increased to 313/264 with the cold weather and scoobysport downpipe and decat centre section I would be happier if more fuel was used in the upper areas of the curve.

Has anyone fitted this module from HKS? How simple is it to fit? Can it supply more fuel only when a certain RPM is reached?

Any comments appreciated.

Gethin
MY97 WRX

Gethin,

The HKS AFR changes the voltage output from the AFM across the range. So it will make the car richer overall.

There are alternative products that have more adjustment. I know Grid do one, and most of the other Jap tuning Co's.

They are easy to fit, but take time to setup. Really need a rolling road, or an AFR meter, and ideally a EGT gauge.

Try Racelogic/Blitz.

Mark.

Hmmm.....

The Possum LINK sure seems the way to go....when funds will allow! I have seen the unit in action with Bob Rawle and it seems the business.

I might give the HKS AFR a try to see if will enhance the richness at least a little...if I get no joy then it's saving up time !!!

Thanks for the inputs,

Gethin.

Why does everyone say that HKS AFR only INCREASES the mixture and makes it richer when it very nicely also DECREASES the richness and leans the mixture (6 steps each way). As those of you who contributed know from my humble self, I tried the effect of the AFR module with the standard(STi5)ecu and the LambdaLink and the mixture was just about to become reasonably correct when the AFR switch was in 3rd and 4th position in the MINUS direction. So, AFR module can do things it has been made for if used with another device which can tell us a) what is actually happening, and b) what to do in terms of necessary adjustments. Surprised (once again) to see how people dismiss things without ever having used them to their complete ability. Which, of course, does not mean in any way that other devices could not be more precise, advanced, etc.

Gethin, get an AFR and get a LambdaLink and you will be able to achieve pretty good results. Talk to Bob R. who will also be able to tell you what a device called InterceptLink from the Possum brains in NZ can do. It is fundamentally the same thing, but far more advanced,elaborated and precise.

Oh, yes AFR module has a '0' position which is (as per manufacturer's claims) a bypas to the normal ecu operation in terms of air/fuel mixture.

regards
q.

[This message has been edited by quattro (edited 13-12-1999).]

Forgot to mention something. Pardon my total ignorance, Sti5 ecu, if anything, runs the engine extremely RICH throughout its operating range, and, unless there is a missing fuel pressure or similar there should be no problem with lean mixture. I tried my engine with 97RON up to 6500rpm with the standard ecu and AFR module set midway down the MINUS half of the adjustment range and nothing detonated!

q.

Who supplies the Lambdalink ? How much ? What is the InterceptLink ? How much !!

I can probably fit the AFR myself, is the Lambdalink / InterceptLink quite straight forward to set up? Bob R what do you think on this one? We briefly had a chat on Saturday, but I did not want to totally monopolise your time there!

I'd also like to get some gauges like AFR, EGT, Boost etc... is there a all in one digital device to do these things? Or do I have to get seperate gauges? Are they straight forward to install? ( How long is a peice of string?!! http://bbs.scoobynet.co.uk/smile.gif )I have good eletronics and computers experience.

Thanks for any advice again!

Cheers,

Gethin.