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So I came across a possible alternate explanation for the KR. My passenger side motor mount was sagging and the center bolt was resting on the cross member under the mount. I have the RX8Performance mounts, which I am really happy with, but it seems the heat from the downpipe is just too much for the bushings. Scott was nice enough to send me a replacement set of bushings (thank you!) after the first one started squishing. I put some heat shield between the pipe and the mount and this one lasted quite a bit longer. I noticed my idle has been getting lumpier so I checked it today and that is when I found that the bushing had sagged enough to the point where the bolt was resting on the cross member. I shimmed it up so the bolt is no longer touching. Idle is noticeably smoother. I did 3 more logs and 2nd gear is pretty much worthless for logs now as the wheels just spun in all three logs Still no sign of timing getting pulled. The scientist in me wants to run my previous timing to compare but I'm getting good results now so the risk isn't worth the data for me at this point...
As far as I'm aware .... IAT has no effect on timing .
My understanding is that IAT has a separate (and subtle) ignition retard table that is inaccessible in ATR and similar to the coolant compensation. BUT I have never done a back to back test under load. Trying to find the info on it, but searching is only getting a lot of crap threads.
The IAT map applies a load factor, so how you have the ignition load map set up determines the impact. I suspect that the relationship has never really been explored in detail here. The limited number of map cells is a factor as well.
Could be motor mount related, but then wouldn't it be constant or at least predictable?
Just to preface, I am not convinced of anything here. I am just looking at all the pieces and considering what is possible/plausible. Here are a few logs I found that had similar IAT and load. The earlier logs (4.15) had no timing pulled, but the later (4.34) did have timing pulled. I looked at the ptm file differences and I had actually thrown more full in to combat the KR in the 4.34 version. Could be that the mount had became more deformed between the 4.15 logs and 4.34 logs allowing metal to metal contact where previously there was none. Could be other things...
The IAT map applies a load factor, so how you have the ignition load map set up determines the impact. I suspect that the relationship has never really been explored in detail here. The limited number of map cells is a factor as well.
This is interesting to me. But I'm a little confused on which direction this would go. With a higher IAT we would see a higher or lower calc load, all other things equal? I need to spend some time reading about load calculation and how all the variables play into it...
The IAT map applies a load factor, so how you have the ignition load map set up determines the impact. I suspect that the relationship has never really been explored in detail here. The limited number of map cells is a factor as well.
Vaguely remember something effecting load calc as it applies to AFR and timing, but not actual load. That is, it pushes you from the 1.0 load to 1.05 load on timing and desired AFR but it does not effect actual g/sec. There has been so much misinformation strewn about it's hard to get a straight answer from searching.
Is that what you're talking about for IAT? and if so is there any good reference you can link? I'm about to start looking in the subie forums for better info.
The IAT map applies a load factor, so how you have the ignition load map set up determines the impact. I suspect that the relationship has never really been explored in detail here. The limited number of map cells is a factor as well.
It applies a factor to the 'max calc load ' table but does nothing to the actual calculated load .
The only way the 'max calc. load ' table can affect timing is if the actual load exceeds the values set in that table. This never happens at any stage unless the values in that table are set too low (or there is a sensor fault) , in which case the effect would be negligible anyway.
It is possible that once the 'max calc load' cieling is breached that timing will switch to this table :
I have never tested this but it does seem logical that Mazda would want to reduce timing if the load was too high.
If it was the case , trying to use this map in an FI application would be very risky.
Edit : scratch that thought ..... just remembered some logs i did a couple of days ago on an NA car where max calc load table was exceeded .................timing is still per the 'leading timing' map .
As you can see it applies a percentage compensation to mass air flow which is very low until you get into both high flow and high temperatures. Maybe someone can find it on our ECU with Mazda Edit, or if we still have an ECU expert on the site they can chime in.
As you can see it applies a percentage compensation to mass air flow which is very low until you get into both high flow and high temperatures. Maybe someone can find it on our ECU with Mazda Edit, or if we still have an ECU expert on the site they can chime in.
Had a quick look through .......... saw nothing like that in M/E
It would be easy enough to do an experiment proving if temp affected load just by adjusting the temp compensation table on back to back logs with the same IAT
IAT clearly an integral part of the control system. Mazda went to great lengths to monitor it for accuracy if you go through all the literature. We likely do not have access to all the locations where it comes into play ...
IAT clearly an integral part of the control system. Mazda went to great lengths to monitor it for accuracy if you go through all the literature. We likely do not have access to all the locations where it comes into play ...
That is a generalised formula that doesn't take into account that the mass flow sensor used on an RX8 (and most modern cars) does not need correction factors for temp or baro.
How about doing the test I mentioned above to prove it one way or the other .......
sense we know that the calc. load max, calc. load max-Baro, calc. load max-IAT, all multiply. but how and when is speculation.
I noticed with the IAT max load at higher temps the multiplayer goes down, meaning the calc load could go down placing you in a different spot on the map, if it multiplied all the time, but it doesn't seem too, or the weight it carries isn't much. that makes sense to me. and for a NA car when its hotter you need less fuel. but a boosted car should pull timing.
regardless we mess with those values to make it so we can exceed 200% calculated load. so I think by doing that we are basically just overriding any kind of effect temps can have on us. and with the original intent of a NA car maybe its a minimal effect, while boosted cars its different.
I have a version of Mazdaspeed ATR it has 3 maps regarding Ignition BAT (Boost Air Temp) and ECT (Coolant Temp)
As you can see not only does it pull timing based on BAT, it also does it on coolent temp.
the other map shows at what load does it use that map, its pretty much flat but at 6krpms it will only use 70% of the requested pull of timing if those temps are reached.
I am glad there is no ill effect of moving the IAT sensor, maybe its for the maf to better understand what kind of airflow its getting? hot air would require less voltage from the filiment meaning it would read less air.
also note that the mazdaspeed has IAT with Maf sensor, as well as the BAT sensor.
I am glad there is no ill effect of moving the IAT sensor, maybe its for the maf to better understand what kind of airflow its getting? hot air would require less voltage from the filiment meaning it would read less air.
also note that the mazdaspeed has IAT with Maf sensor, as well as the BAT sensor.
Awesome stuff Fazda! This was my understanding of the IAT sensor in the RX8 MAF, so the MAF can autocorrect based on temp.
Interesting the the Speed3 has a separate BAT sensor. So is it that the IAT in the Speed3 MAF perfoms the same auto correcting function for the MAF as ours, but timing is only affected based on the BAT?
09-05-2015, 04:52 PM
Still no sign of timing getting pulled. The scientist in me wants to run my previous timing to compare but I'm getting good results now so the risk isn't worth the data for me at this point...
maybe I'll post a thread on my build. Stay tuned ladies.
