Recommended Wideband and Target AFR at WOT
Discussion
Had the opportunity to attend a rolling road day on Saturday. results were a bit disappointing, down a few BHP since the last dyno a couple of years ago The car has been de-catted since then and with a few other tweaks I was expecting a bit more.
Result: 320 FWHP / 275 RWHP (Transmission loss 14.0%)
Previous: 337 FWHP / 281 RWHP (Transmission loss 16.6%)
Based on the printouts the car was running very rich, with the AFR dropping into the low 11s / high 10s, on the Dyno gauge. My Zeitronix ZT-3 gauge, which I have been using for mapping on the road, was reading about a point higher according to my MS log, but still richer then I would like.
Just wanted to check what would be a good target AFR at WOT (current target is 12.8) and whether getting this right is likely to have a significant impact on HP. How rich is too rich?
My other concern is with the Zeitronix wideband. I originally bought this for another project and only installed it last year when my Tech edge wideband stopped working. It seems to be set up correctly with the gauge and megasquirt giving the same readings. But is not the most responsive, with relatively large lags showing up in the megasquirt logs. Thinking of replacing this with an AEM Uego, which seem to be well thought off, or the new X-series seems to be getting good reviews. Any others I Should consider?
Result: 320 FWHP / 275 RWHP (Transmission loss 14.0%)
Previous: 337 FWHP / 281 RWHP (Transmission loss 16.6%)
Based on the printouts the car was running very rich, with the AFR dropping into the low 11s / high 10s, on the Dyno gauge. My Zeitronix ZT-3 gauge, which I have been using for mapping on the road, was reading about a point higher according to my MS log, but still richer then I would like.
Just wanted to check what would be a good target AFR at WOT (current target is 12.8) and whether getting this right is likely to have a significant impact on HP. How rich is too rich?
My other concern is with the Zeitronix wideband. I originally bought this for another project and only installed it last year when my Tech edge wideband stopped working. It seems to be set up correctly with the gauge and megasquirt giving the same readings. But is not the most responsive, with relatively large lags showing up in the megasquirt logs. Thinking of replacing this with an AEM Uego, which seem to be well thought off, or the new X-series seems to be getting good reviews. Any others I Should consider?
I`d say 12.8 is about where you want to be. Its what i try to run at.
wot low rpm up to about 3k rpm i go for 12.5 afr and then above 3k rpm i go for 12.8.
From my research on the subject i`d say being normally aspirated, 10`s and 11`s afr are going to loose you some bhp.
As for wideband i`m using an AEM. Seems good but must admitt i`ve never had it checked on a rolling road. I recently asked my MOT man to check it against his tester but he said he couldnt as his didnt measure afr only CO and HC`s.
wot low rpm up to about 3k rpm i go for 12.5 afr and then above 3k rpm i go for 12.8.
From my research on the subject i`d say being normally aspirated, 10`s and 11`s afr are going to loose you some bhp.
As for wideband i`m using an AEM. Seems good but must admitt i`ve never had it checked on a rolling road. I recently asked my MOT man to check it against his tester but he said he couldnt as his didnt measure afr only CO and HC`s.
I took a log during my MOT and thought the wide band was pretty accurate during the test. My gauge was reading 14.6-14.7 during the fast idle test vs the MOT Lambda test result of 1.01.
General concensus on the day was that the dyno lambda was pretty accurate vs gauges fitted on other cars, so looks like mine isn’t accurate when rich. Most of the other guys also reckoned the dyno was giving low results, but I suspect that is normally the case at these events.
General concensus on the day was that the dyno lambda was pretty accurate vs gauges fitted on other cars, so looks like mine isn’t accurate when rich. Most of the other guys also reckoned the dyno was giving low results, but I suspect that is normally the case at these events.
Interesting read through the ‘post your dyno curve’ thread. Regular on here with almost identical engine set up to mine posted 342.5 BHP at the fly and 275.3 BHP at the wheels on a Dyno Dynamics RR. Power at the wheels curve is virtually identical to mine, but transmission losses are 19.6% vs my 14%.
This gives me some reassurance that my engine is in a pretty good state. May be 350 BHP is achievable with the right fueling, ACT carbon plenum fitted and the right dyno!
This gives me some reassurance that my engine is in a pretty good state. May be 350 BHP is achievable with the right fueling, ACT carbon plenum fitted and the right dyno!
Gassing Station | Chimaera | Top of Page | What's New | My Stuff