sc_sjo

iTrader: (7)

Hi all

I've been pondering this for a while. The OEM ECU on a UK classic (or specifically a MY99 UK car) does not measure inlet charge temperature (as no sensor is present). I can only assume that the knock strategy is relied on when it comes to high IAT's.

Now from what I understand, the Apexi PFC doesn't have a very good knock strategy, I think i've only seen a "knock count" value (does it have knock retard at all?).

If the above assumptions are correct, i'm curious as to how dangerous PFC really is on these cars in high IAT conditions (eg a hot summers day with a standard i/c). I mean, if the car is mapped on a cold day, what's it going to be like on a hot one? I'd be curious to how the mappers get around this, if they do at all.

I'm pretty surprised these cars don't all come with IAT sensors. Pretty daft.


Discuss

joz8968

iTrader: (13)

The PFC doesn't alter ign. tmg. whatsoever. It relies on the expertise of the mapper, so that it "never" causes det - i.e. mapped safely.

If you also have the Commander, then you can monitor the knocking level, so can see what's happening at any point in time.

Not sure how projected ambient temps are mapped around, though.

sc_sjo

iTrader: (7)

Yes, this is what I suspected. I'm curious to know though how a mapper can predict how much spark will need to be taken out when the charge temps are considerably higher in the summer. I would expect this to have quite a negative effect during the cooler periods.

When I map a car I have a rule of thumb of retarding so many degrees of spark angle for every degree increase in inlet temps above say 55c IAT. Not really sure how you could simulate this on the PFC with mapping.

Always interested on being educated though

joz8968

iTrader: (13)

Yeah, I'd like to know how the mapper/knows how much ign to take out on a hot mapping day (to account for colder days) too. Or what the strategy is........

Sabas

iTrader: (22)

this is something I would like to know too

joz8968

iTrader: (13)

lol were all like expectant chicks waiting to be fed:-

sc_sjo

iTrader: (7)

Bump

sc_sjo

iTrader: (7)

Shame noone in the know has replied yet, or perhaps they're not in the know?

joz8968

iTrader: (13)

I would have thought JGM knows the strategy for mapping it...............

Alan Jeffery

Basic principles here. Intake temp is only partially referred to on any car. It's to allow for the differences encountered by running the car in either a Swedish Winter, or an African Summer. On a turbo car, it's charge temp that's the issue, which can be high even on a cold day. A stock Impreza ECU doesn't refer to it, relying only on knock detection, which is patchy at best. All mappers have at some stage come across a Scooby that's detting its head off, totally ignored by the ECU.
I'd say the trick is to set it up so it doesn't do it in the first place.
Correction tables have a measure of sliding scale, which should allow for extremes, if properly set up.

sc_sjo

iTrader: (7)

Thanks for the comment Alan. In the above I was solely referring to the inlet air temps the engine actually sees, charge temps.

Unless I misunderstood what you said, it seems that the way to safely map these is to do it 'worst case scenario' based on final spark angle you'd use with very hot IAT/ICT's to avoid det.. To me this seems that the final spark angle will end up much less than optimum for those cooler days..


Time for a decent ecu methinks...

Dutch Scooby lover

iTrader: (3)

I might know someone who wants to buy the PFC, if you decide to sell it.s

Sabas

iTrader: (22)

so the apexi ecu isn't that great?

typeRv4

It has limitations like any ecu.

I'd say the apexi is good but if you pay more there are better ECU's out there.

To the original posters question - yes the apexi is safe on a non sti. The temperature sensor has a very limited use.

71/200

iTrader: (2)

You claim to be a mapper, i view this from the statement "when i map a car" so i could be wrong here but the way im reading this is ,

You map cars for a hobby or to earn money? Have You have been asked to map a scooby on a PFC but you dont have a clue, so you come on here to extract the answers from the guys that do know!

Sorry mate if you have to ask, you should not be doing it!

Maybe i got you totally wrong and you want to map your own car on a PFC lol.

Too many self proclaimed mappers on here, the guys that really know what they are doing dont ask questions like this and are well respected. If this is some kind of ploy to get you out of a hole for something you dont know the solution for, pack away the laptop and get the sponge and bucket out again mate!

Alan Jeffery

"Worst case scenario" is the fact that the owner sometimes drives it ..

sc_sjo

iTrader: (7)

I never claimed to be 'a mapper' (as in professional tuner), so yes you are wrong.

Hobby.

Nope

I must disagree, information on Apexi strategies is extremely sketchy, hence asking the community.

Correct.

It's not a competition. And yes, i'm sure all the well respected guys on here were born with their knowledge and didn't have to ask any questions.

Actually it's not a ploy for anything beyond my original question. I have broad general knowledge on engineering and tuning but my question was specific to how scooby 'mappers' as you call them getting around (read: bodging) the limitations of the OEM ECU and Apexi PFC with regards to managing charge temperatures. It was a question out of personal interest and curiousity, so no need to start piping up really