DazC

iTrader: (1)

I have a small issue with getting the transients right on a 1600cc CVH 600cc injectors, 7.5:1 CR, big valve big port head, YB throttle body.

Basically, I set the positive gain to the point were it'll hold a steady AFR from idle and when opening throttle and the decay rate to match.

Now if I rev it slowly, It'll rev reasonably well. If I snap the throttle open, it'll hold back. If I watch the afr, it'll run lean and as soon as it starts to hold back I lift off and it'll go rich for a brief moment. The lean point appear at 1750rpm to 200rpm. This occurs at the same point all the time. Once above 2k rpm, it'll rev clean with no issues.

So I then richened it up on the positive gain and then all it does is dump that much fuel in that it won't even rev (9:1 afr and richer), then when it gets past the flat spot, it's got the same lean spot immediately after. If I up the gain and decrease the decay, It does exactly the same. I can get it to rev clean for a few 100 rpm and then it hits the lean spot.

I even added some negative gain and decay but all that does is make it rich after I have come off throttle.

If I open the throttle and hold it at a constant, It'll rev, hit the lean spot then just hunt/kangaroo. Whilst this is happening, the AFR is rich/lean/rich/lean. Afr's ranging from 13.4:1 to 21.5:1.

The only way I can seem to get it to rev cleaner is if I highlight the base fuel injection map along the 800 and 1000mbar line from 1000rpm to 2000 rpm and set them to around 10ms injector duration with idle and cruise being around 1.8ms. Obviously this is wrong as it creats a huge lump in the middle of the map but it's not in the cruise or idle sites so won't affect it detrimentally. It's also not perfect when I did this either as the flat spot was there ever so slightly but nearly gone.

Anyone have any suggestions? I'll get some screen grabs of the software some time and a bit of an explaination about what I have tried.

To me I have it in the back of my head that there is a setting somewhere that is affecting the fueling between 1 and 2k but it's nothing within the fueling corrections that I can see.

Any input is most appreciated!

The DIVA

iTrader: (3)

Daz, what you using to map ? IEMS ?

DazC

iTrader: (1)

Life Racing LifeCal, Rob.

It's for an F88RS ECU, not IAW.

markk

iTrader: (2)

is the software downloadable from somewhere mate so we can have a look ?

its not good me telling you how to have a go with it with my Gems software if its nothing like !

DazC

iTrader: (1)

Mark,

Whats your e-mail address?

SiZT

Is it a freshly ported head or has it been on a perfectly good running engine before?

DazC

iTrader: (1)

It was on a perfectly fine engine before. All it's had is a new set of valves. It's one of Karl's heads.

markk

iTrader: (2)

hmm strange with the mail, mail me without the attachment daz

DazC

iTrader: (1)

Done.