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I wonder if it's getting into valve float?

Weather has packed it in here so time to have a look through some data logs

I'm thinking I have a valve float issue. Cylair climbs till about 5200rpm and then starts to drop, before the rockers were fitted cylair continued to climb until it changed up. Cylair is up so there is more flow and better yet there was no knock retard and the fuel trim numbers are almost identical bank to bank so the injectors have done the trick and it also looks like the IAT's are down about 5-10°C too.

Screen shot of what could possibly be valve float? Cylair climbs until about 5200rpm and then tappers off until it spikes again as the gear change occurs at about 5500rpm. I'm thinking it might be worth while lowering the shift points so it doesn't go into valve float to preserve the valve springs until I fit some new ones.

Next query, I don't think the injector data is correct. Max injector pulse is showing as about 8.5ms and only 28% DC? ADX and XDL attached.

how does the cylair compare to before hand ? I am assuming with the higher ratio rockers your seeing more cylair earlier than you would have with the old rockers ? it looks like its pretty much flat lining a bit over 3000rpm till redline, is this how it was before ?

Holden202T wrote:how does the cylair compare to before hand ? I am assuming with the higher ratio rockers your seeing more cylair earlier than you would have with the old rockers ? it looks like its pretty much flat lining a bit over 3000rpm till redline, is this how it was before ?

It kinda looks that way due to scaling. The curve seems very similar to before and up a bit. Earlier logs show it peaking just over 900 Cylair.

You have fuel PW calcs that are based on a engine rev not cycle. Try these...
Fuel PW = X / 65.536
Inj DC = (X / (2000 * (1/(Y/60)))) * 100 <--- X linked to injector BPW and Y linked to RPM

The DC is the fuel PW and does not allow for opening time - or the delivered PW. Need to add whatever is in the injector opening time table for the current or an average engine running battery volts. Could also get tricky and add it as a lookup table in the ADX.

Can you have 3 graphs on 1 monitor? I'm not sure the "valve float" (cylinder air spike) lines up with the maximum RPM on that chart. If it doesn't and the RPM is still increasing after the spike then its not valve float because valve float would continue on once it had started until the condition that caused it (high rpm?) had ceased.

VL400 wrote:You have fuel PW calcs that are based on a engine rev not cycle. Try these...
Fuel PW = X / 65.536
Inj DC = (X / (2000 * (1/(Y/60)))) * 100 <--- X linked to injector BPW and Y linked to RPM

The DC is the fuel PW and does not allow for opening time - or the delivered PW. Need to add whatever is in the injector opening time table for the current or an average engine running battery volts. Could also get tricky and add it as a lookup table in the ADX.

Awesome, the numbers look much better now.

MAGP wrote:Can you have 3 graphs on 1 monitor? I'm not sure the "valve float" (cylinder air spike) lines up with the maximum RPM on that chart. If it doesn't and the RPM is still increasing after the spike then its not valve float because valve float would continue on once it had started until the condition that caused it (high rpm?) had ceased.

The spike is after max rpm. see above. The monitors don't quiet line up but both are at the same time interval.

Thanks for the new pic.
The new pic shows the spike is occurring on deceleration. If it was n/a I'd say the exhaust scavenging was pulling air through (high vacuum) but yours is s/c so I'm not sure if that would happen.

The spike is on the gear change, I back off just after it started to pull in 3rd, speed limits and all........