7mgte fuel and igniton maps? (pics)

**chris davey** · 09-03-2006, 02:10 PM

I have painted on basically where a stock turbo 1jz will go as you plant it. This is just a guide obviously but you get the idea.

P16 and P17 are about the stock boost level. You see in the upper rev ranges as boost increases timing is retarded. See the difference between P16 and P20 at 7000rpm. Increase boost = increased cylinder pressure so you retard to timing to prevent detonation.

Also you should know about ramping up after peak torque. I would imagine that a stock turbo 1j peak torque would be around 5000rpm or so. If the boost level is constant then after peak torque (the point on the map that uses the most fuel to maintain the same air fuel ratio) the cylinder pressures drop a little and a bit more timing can be advanced. ie. teh difference between 4800rpm and 7000rpm at p20.

**chris davey** · 09-03-2006, 02:28 PM

Here is another. The first line that goes to 8psi or so is stock 1jz (approx) and the other line is how my car was going with ta45s in 1st gear. +ve boost at 3000rpm, sits on 5psi for a while and then 16psi at 5700rpm. Gearing and ecu in limp mode to blame!

This isn't my ignition map obviously but that is basically where my car was making boost as opposed to rpm.

**kemicalx** · 09-03-2006, 03:57 PM

cheers man your a legend, that has helped me get a grasp on what needs to be done i'd give you another rep point if i could

**chris davey** · 09-03-2006, 04:00 PM

no probs mate. I am learning as I am going

**kemicalx** · 11-03-2006, 05:28 PM

Another question

This time the fuel maps, I'm just wondering if there is a way of calculating how long i will need to keep injectors running at each load/rpm point, Or is that something that will require the car running (and at the desired rpm/load) and then adjusting each point so the afr is where you want it? I'll most likely get the motor running with the stock 440s to begin with.

Thanks all,
Ashlin.

**chris davey** · 11-03-2006, 05:55 PM

the megasquirt guys doing it by using volumetric efficiency. I don't understand that enough to use it though. Using a wideband o2 sensor is a hell of a lot easier IMO

**pilot** · 11-03-2006, 06:10 PM

As Chris aid, it is possible to calculate it using some parameters like RPM, throttle postion, etc; but you will always need a correction factor (volumetric efficiency) which changes the ideal value pretty much.

**kemicalx** · 12-03-2006, 01:19 AM

mmmk cheers guys, so in that case, should I just set my fuel trim higher for the first engine start so the whole rev range will be running rich, so then I can just knock the trim back to a nice afr (about 13 yer?) as well make any adjustments to individual load points that need it.

edit - for anyones that interested in volumetric efficiency and how to calculate it i found a few sites to have a read through.

http://www.installuniversity.com/ins...n_9.012000.htm
http://www.offroaders.com/info/tech-...eading/cfm.htm

So it looks like I won't be calculating anything until the motor is actually running

but if I can get this EMS to work with my 7m i'll be able to log all the parameters i'll need and then can find it for interests sake

**pilot** · 15-03-2006, 04:16 PM

In the case of my Wolf ECU, I can set an "engine starting condition below X RPM". Then I can set the amount of fuel and ignition advance for that given engine speed. What I did was setting 10ms of injection and 5º of ignition advance so that I could start the engine and warm it a little bit. Afterwards you can start tuning. Obviously, these values are referred to a "common" setup (no boost and injectors appropriate for the engine).