rollex

My old skyline didn't have one however it used a flap MAF air meter so it could meter air effectively. You did have to tune it in the hottest weather you would drive it in to be sure it wouldn't ping though, pulling timing on coolant temp helped but would have been better with proper IAT.

Yeah it might get heat soaked but I guess the air is a similar temp and taking up that heat so it is accurate.

Ok cool, it seems intercoolers work much better than I thought. I had no idea.

There are too many sensors I know what is what. I'll try and find a workshop manual.

IAT seems to have an inverse relationship with vehicle speed and almost nothing to do with boost level at all... learn something new everyday! Just to confirm, the IAT sensor is DEFINITELY after the turbo right? It isn't sitting in the intake piping??

Something else, the intake air temperatures seem to drop when I get on boost. Even on the freeway when my speed is already up they always seem to drop after a pull. The only time they go up is idling or cruising after a big pull. I thought the turbo compressing the air would always increase the air temperature due to compression? The only answer I have is the IAT sensor is before the turbo, as higher speed and lower pressure (vacuum in the intake when on boost) results in lower temperature. Someone told me the IAT sensor is part of the MAP sensor and is in the manifold, if so why does the IAT drop when on boost?

What PID can I log knock with in livelink? If I load all variables for my strategy after validation there are no knock variables left. All I can seem to log is spark adder? Are there other PIDs that don't show up in the database that I could log?

Awesome, thanks for that.

The datalogging seems pretty good in livelink. I think I'm understandin the difference between the variables, some can only be polled via the slower speed datalogging methods with lower resolution. Trying to figure out the best way to datalog knock, think I'll need to better understand how the spark adder is calculated as that will most likely tell me what the "knock" is. Found that in my old tune (before I got it retuned with sct) they had turned knock retard down to a max of 3 degrees.... boost map looks really odd as well which explains why the boost was improved so much when I got it retuned.

lol I was wondering why he wasn't posting in here. maybe he is allergic to newbs like me

Ok that helps. Can someone explain the difference between OBD, DMR and PID in livelink? I'm guessing PID is the raw value but I'm unsure the difference between the other two. Also any good guides of which items to log. It appears there are multiple that seem to be the same thing so it is quite hard to filter through them to find the most "correct" one.

How do you determine the breakpoint? Can someone explain why a breakpoint is needed as well, what is the physical process which makes the injectors not flow linearly? Do some PCMs have a full 2D injector map? Or do they all have a simple 3 point curve ? Excuse my ignorance, when you say manifold you mean after the throttle body yeah?

Yep I agree that sounds much easier. I guess what I was saying is use ID1000 data, get commanded AFR matching actual AFR and then once it is all done I can tweak the injector slope slightly, then just offset the map slightly (make it slightly leaner to account for the increased slope) then I will effectively have a rising rate fuel reg meaning if I get a higher duty cycle for any reason it will run slightly richer than I've asked it to, eg running more boost due to something failing etc. I guess if I tune it at 11.5 everything will be fine, I just like building some AFR safety into the tune if something happens as I've done on other cars with real time tuning. Perhaps I'm better off using the other built in protection like max airflow or something like that or simply not worrying about it. Something else is intake temperature measured before or after the turbo? If it is after the turbo I could manipulate the air temp enrichment to achieve what I'm after as more boost equals more heat.

Yeah I just got thrown by people saying a "full SD tune" is a lot of work. It sounds like I don't need to do much at all if the factory maps are spot on for my changes. It also sounds like I can achieve my richer at higher boost just by doing the good old injector slope hacking. If I get everything spot on at the boost I want, then I can increase the injector slope slightly to get effectively a rising rate. To be honest it sounds pretty easy to do all of this, sounds like easy money for some of the big workshop tuners! Now it is time to start reading about the spark side of things as I think I understand how the fueling works now. edit: Is there anyway to increase the resolution of the TPS vs RPM map? Manual BF xr6t november 2006 build. Does this change much?

Yep mine has the high resolution tables. So anther question, if I have only changed injectors and front mount and get the injectors dialled in correctly why do I need to adjust the speed density tables? Shouldn't they still be accurate for the engine /cams and deliver commanded afr.

Anyone ?

Another question is how good is the knock detection in these cars, can I simply log knock and it will let me know if there is mild detonation? Or do I require knock ears?

Well if I'm running low boost then I can probably get away with 12 or 12.5 AFR without detonating, eg half throttle on a straight line or 1/4 throttle up a hill. If I'm WOT then I will need closer to 11-11.5:1 with 16+ psi. The issue is load isn't proportional to your foot position, you can get close to full load with half throttle going up a hill. Going down a hill at a lower speed you won't get f*ck all load with half throttle. The reason I asked is I normally tune load vs rpm. Eg very easy to simply add more fuel at peak torque at full load, doesn't matter if I'm 25% or 100% throttle, if there is that much airflow it will be that rich. There is a good reason why the ignition tables are load vs rpm, because going up a hill vs going down a hill at the same boost and throttle position will accept differing amounts of spark before detonating, I just don't get why AFR is programmed differently in these cars.

I posted this on HPT but wondering if anyone has different answers here: Ok so I've been reading the lasota racing manual and msot of it is stuff I already understand but it is definitely a good read. The following questions are mainly about speed density as that is the thing that is doing my head in. To try and understand things better I've assumed two things in this scenario, wide open throttle (TPS of 50%) and no variable cam timing, eg it is locked and no other correction maps in play, eg ignoring temp etc. This means the simplified equation is:fuel_injected = commanded lambda (fuel base vs rpm vs tps) * MAP at x cam degrees at y rpm * actual air pressure in inlet This means the PCM will figure out the fuel to inject based on the air pressure * volumetric efficiency in the MAP per airmass high res table * commanded AFR Now this brings a few questions up. What if I want to run 11:1 AFR at WOT with 18psi but I want to run 12:1 AFR at WOT with 12 psi? The main fuel base map is rpm vs TPS? Why is it not rpm vs load eg like the spark maps? Now I'm sure I could get the result I'm after by tweaking the injector slopes or a bunch of other methods but that means making a hack tune which isn't what I want to do. The next question is what about the cam position, how is this commanded? I'm guessing the reason the cam angle vs rpm table exists is because the different cam angles change volumetric efficiency? eg the amount of fuel required to obtain a given AFR at a given psi changes Also can anyone answer this question about map resolution?http://www.hptuners.com/forum/showthread.php?53120-help-rolls-transition-from-a-tuna-to-a-tuner&p=395279&viewfull=1#post395279

Yeah I'm going to spend the weekend reading all of the guides to get an understanding then start doing some datalogging to confirm what my car is doing with the current tune. I still need to purchase a wideband so be a few weeks away before I start playing.

I just bought it, $75 isn't much for something that I'll get enjoyment out of doing. Can you use the moates software with our PCMs? Looks like it would be an interesting way to get into the more "custom" side of things, eg if you want to make the check engine light flash on knock or other random software mods. edit: Looks like it is for the previous ECUs before the ones we use now.

$75 for his book, is it that high quality to be worth buying? If it is a proper book with long winded explanations I would consider buying it, but if it is just some guy who has compiled effectively free forum posts maybe not.

Fudging injector values sounds like a hack way to tune a car, I've got the rest of my life to get this right so learning to do it the proper way will be interesting for me. What does "full SD" mean?

Cool thanks

http://www.hptuners.com/forum/showthread.php?53120-help-rolls-transition-from-a-tuna-to-a-tuner&p=394600#post394600