i've emptied my PM's a little

this morning I will attempt a couple of pulls... original ROM just 1 point richer under boost...

 

ok - this is the last known GOOD log:


And this is a pull from this morning, roughly the same airtemp, same tune EXCEPT for the fuelmap which is 1 full point richer - hardware wise the car now has a 3" downpipe and a 3" metal cat:


A back-to-back, same bit of road, moments after the above pull:


Thoughts? Comments?

 

wow seeing the difference a downpipe hfc makes with load and boost. I had a similar problem with afr and knock. I swapped the relay and found the uicp at the intercooler which is stock and never been touched was a little bit loose. It would passed qa smoke test but leak a little once it got hot making the intercooler heatsoak.

 

note the rpm axis on the second graph only goes to 6200rpm, whereas the first goes to 7200 (i ran out of traffic free road )
(edit - I updated top graph to remove rpm's that dont exist in the 2/3 graphs)

So the question is:

Has the 3" downpipe + HFC leaned out the car? OR is the fuel pump on the way out?

I am not sure if 1pt richer AFR in the map equates to 1pt richer in actual AFR...

btw - the car runs pretty good, is it a bit more peppier at part-throttle - this is due to the 3"DP+HFC...

 

ya that was a big oversight on my part. glad you pointed that out since i was lost on that much gain and holding that much boost with out just blowing hot air.

 

Tephra, I would not suspect anything sinister from the DP at all. But I have seen some aftermarket cats that are worse than stock. It wouldn't take terribly long to swap with OEM to try it out. What do you think?

 

yeah i can't see the DP making too much of a difference, cat certainly could..

I guess I could try swapping it back - urg I hate getting under the car hehe

so what about a failing fuel pump theory?

I did 4 back-to-back 4th gear pulls this morning, all AFR's were basically in the same... I've added another pull to the above post, it was done a minute after the second pull, no changes...

 

I have updated the first graph so it doesn't have the high RPM's that was confusing the issue

 

My car is proof positive of a little more detonation in hot weather, but it was very slight, not all of the sudden. Unless the temperature changed dramatically, I think you would have seen it creep up in your logs. If you're too close to the limit, you'll see 2 and 3 counts, not insane 20+ counts.

 

well I tuned in winter, so 15-20C ambient air temps.

the knocks were in hot weather, so 30-35C ambient air temps.

that Hartman guy reckons you need 0.5 octane increase for every 10C increase in air temp.

Yes I think so as well, so that begs the question, is it bad gas, dieing fuel pump, bad relay or something else?

Given the actual AFR only changed by about 0.5 AFR - and I changed the map by 1.0AFR I tend to think its a fueling problem.

hot weather + abnormally lean = big knock?

 

Tephra,

What are your Mivec settings in that area you are having an "issue" with richening up? More exhaust retard / intake advance will make the logged AFR leaner on spool/peak trq.

- Bryan

 

Basically a copy of your MIVEC maps Bryan!

 

wow after reading all this, I dont think I am going to upgrade my X at all. Im way too scared now and this is insane. I hope you get it all figured out, seems the 1B11 is a fail for the evo. Dual Mivec isnt helping either. Weak rings, weak valves, weak rod bolts and many more things are just simply scaring me!

 

lol

well apart from the fuel pump relay, and possible fuel pump issue, and "ring end closeness" theory its all good

 

I've asked the mods, to split the AFR tuning theory into another thread - keep that and this discussion separate. Both being very informative