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Posted: Tue Nov 26, 2013 9:19 am
by wurlycorner
Merlin wrote:If you are too rich you will be down on power
:oops: yep I know that :lol: I assumed they'd said something more specific about the ludes that were tested?

Re: the print outs, there were a load from the national meet that can be used for comparison of shape too, if you look at them (if they're up? :? )

Posted: Tue Nov 26, 2013 9:23 am
by NCCMUR
:lol: well i know the o2 sensor is a bit tired (although its not throwing a light) so ill replace that first and see how it goes

Posted: Tue Nov 26, 2013 9:27 am
by Merlin
One or two were running rich either all the way through the rev range or in certain parts. They stick a sensor up your exhaust which monitors the ratio in the exhaust gasses.

Posted: Tue Nov 26, 2013 9:28 am
by wurlycorner
Merlin wrote:Fuelling and having too much fuel in the exhaust gas is controlled and can be influenced by a multitude of things. Off the top of my head (but the service manual will tell you more):

TPS
MAP sensor
IAT sensor
Engine water temp sensor
Ignition timing
ECU
Water temp sensor controls mixture until the O2 sensor has warmed up and starts reading, then that takes over.

If your engine races at idle as it warms up, it's because the mixture is staying too rich because the ECU is running on a default value because your coolant temp sensor is knackered (it doesn't log a fault code for this IME, annoyingly). If it's too rich once the engine is warm, the O2 sensor should have taken over by then, so it's not the coolant temp sensor.

Posted: Tue Nov 26, 2013 9:31 am
by wurlycorner
Merlin wrote:One or two were running rich either all the way through the rev range or in certain parts. They stick a sensor up your exhaust which monitors the ratio in the exhaust gasses.
Oooh, that was good then. Powerstation didn't do that bit at the national (but we did get reliable readouts :10: :lol: )

Posted: Tue Nov 26, 2013 9:35 am
by Merlin
If your MAP sensor or IAT sensor is giving false readings more fuel will be added than is needed too.


Different dyno places will do different things depending on the dyno package they have.

Posted: Tue Nov 26, 2013 9:49 am
by wurlycorner
Merlin wrote:If your MAP sensor or IAT sensor is giving false readings more fuel will be added than is needed too.
Yep - in case my post reads as suggesting the other components Merlin listed don't affect it, that wasn't what I meant. My post was just explaining the way that the coolant temp sensor and O2 sensor interact in their effect on it.

Posted: Tue Nov 26, 2013 9:56 am
by Merlin
:D It is one big ball of sensor readings that influence each other.

Merlin wrote:I have looked a the sheets in detail and I can see that the dyno is not reading torque properly over 5K or so. The torque curves do not increase after VTEC, are not as sustained as other dyno results and fall off very quickly. On other dyno's torque hardly dips until after 7K. On this dyno it show my torque dropping off after 6500, Macky 5750, Andy 5250, and newkid 5750. To say that a VTEC engine doesn't produce more torque once VTEC kicks in (Yo) is bullshit. Your arse dyno tells you that isnt true. The rate of acceleration is much more in VTEC than out of VTEC and that is purely down to torque. After looking on the net a bit more it seems that this is a common issue with the DynoDynamics, not reading torque properly over 5K ish.

I compared my graph with the one from Dino's last dyno and were matched each other (almost to the exact torque/bhp) until 4500rpm. After that the DynoDynamics dyno screwed it up.

I have also spotted a potential reason why some cars gave less of a loss on that dyno in comparison with the Honda's. The DynoDynamics Dyno is a load bearing dyno, it puts a resistive force on the roller and measures the torque against the resistance. The amount of resistance added is the Ramp Rate (RR on the dyno sheets). 4cly N/a cars are ran at a ramp rate of 100 while the Focus ST (4cly FI) was ran at a ramp rate of 150. The ST loss was approaching half that of the N/a Honda's.

The more I look at the results and the graphs the more I think the DynoDynamics platform is crap (maybe more to do with the Hypertech one). Doesn't read torque properly, graphs don't show rpm correctly, graphs don't show torque accurately and the graphs don't show anything to do with power at the wheels. Considering the dyno reads power at the wheel and calculates back to the fly, why doesn't it give a whp reading :?

Posted: Tue Nov 26, 2013 11:18 am
by LewisH
That dyno read out looked a bit off, well... more then a bit!

But, ive been to a dyno day where the read outs werent what everyone expected, and all in, it was a fantastic day out. Would love to go to another!

Posted: Tue Nov 26, 2013 12:14 pm
by toyracer69
Maybe Vtec scared the dyno operator and so when the cars went into Vtec he then took his foot off the gas? :D

Would be nice to see any of the graphs.... :lol: