Injector scaling question

[k80rum]

I've got a quick question for those that understand the witchery of injector scaling, as this is my first foray into it.

 

I'm using an Emerald K3 and I think I understand what I need to do, but could do with a second opinion.

 

I originally used the ECU with a different engine/injectors/fuel pressure.

 

I've got a base map for the engine from someone with the same larger injectors and fuel pressure I'm running.

 

Am I right in thinking that ultimately, what's important is that my MSPB figure is the same as the owner of the original map, so that the figures in the fuel map are correct when they get multipled by it?.

 

I can either calculate this by scaling the injectors/fuel pressure, or by directly editing the MSPB figure (which is probably the better thing to do if borrowing a map for the same injectors and pressure)

 

Darren E

 

K80 RUM Website and Emerald maps library

 

Home of the long-term, supercharged Duratec project

[oilyhands]

Darren,

 

That is correct, but the MSPB value is part of the map so if you have used the map in it's entirety then the MSPB value will have carried over too.

 

Mke a note of the injector capacity, fuel pressure and MSPB value in the comments so it will be asy to identify in future..

 

Oily

[rj]

Darren,

 

Just scaling would probably not do it. You need to consider the latency (sp) too.

 

Especially at short opening times this makes a huge difference.

 

/r

[oilyhands]

The latency is pretty much the same for both injectors and is a constant to be subtracted. The nett remaining injector time is the relevant part and this is the only part that is scaled by the MSPB, I'm pretty sure this is netted off before the fuelling calc is made.

 

oily

[k80rum]

Thanks Dave and Regin

 

Regin, I'll double check the latency value, I don't remember seeing it mentioned but I haven't delved into the Additional Maps section much before so I could have missed it.

 

If Dave says it's pretty much the same, hopefully I won't have too much trouble.

 

The car is booked for a rolling road session mid-Sept so I'm aiming for something to get me up and running for a month, just to get some miles on the engine and get it run in.

 

Darren E

 

K80 RUM Website and Emerald maps library

 

Home of the long-term, supercharged Duratec project

 

Edited by - k80rum on 26 Jul 2009 14:46:26

[rj]

Darren,

 

Be careful not to run lean at high RPM

 

What sort of lambda equipment have you?

 

(Might be an LC1 connected to the ECU...)

 

 

 

 

[oilyhands]

It's only when you try to scale the numbers in the injection table itself by a percentage or similar that you get a bproblem because that number *includes* the latency and any scaling will also scale the latency factor and leave you lean. The good thing about scaling the MSPB is that it only applies to the net injector duration after latency has been taken care of IYSWIM.

 

Oily

[rj]

Oily,

 

 

I don't know the Emerald software at all, so I can't comment on it. All I can is to put up the warning finger. However I would think that the latency would make greater impact at lower RPM as the percentage of the "output on" time related to latency is higher at a duration of 1ms than if it's 10ms (IYSWIM )

[k80rum]

Thanks both.

 

Regin, yes I'm using an LC1 with the ECU which'll run in adaptive mapping mode when it's above tickover

 

Darren E

 

K80 RUM Website and Emerald maps library

 

Home of the long-term, supercharged Duratec project