E40 ECM scaling for 160-190lb injectors

[GraphiteSRT]

How would I scale the E40 ECM for 160-190lb injectors?

I currently have my tune scaled 50% which allow up to a 127lb injector.

[mowton]

like 33%....wow thats alot. Will have little or no resolution down in the driveability area. The actual percentage is 63.5 divided by the rated IFR at 80KpA.

Ed M

[GraphiteSRT]

I do not even like my tune scaled 50%. 33 would not work. Are their any other ways of going about this?

[mowton]

I do not even like my tune scaled 50%. 33 would not work. Are their any other ways of going about this?

Not that I am aware of. If I might ask, why such big injectors? Must be a race car where you wouldn't care about driveability......maybe an add-on EFI system in place of the factory system.

Ed M

[DSteck]

Divide your IFR by some number, and multiply the stoich AFR by the same number.

Example... Your injectors flow 80lb. Divide that by two, and multiply stoich so it says 29.4.

[rynez06]

Divide your IFR by some number, and multiply the stoich AFR by the same number.

Example... Your injectors flow 80lb. Divide that by two, and multiply stoich so it says 29.4.

this is what i do , works great, makes it much better for tranny tuning as well

[GNXClone]

I do not even like my tune scaled 50%. 33 would not work. Are their any other ways of going about this?

What do you not like about it? I recently did the 50% scaling on my E40 and it's working rather well IMO. This is a daily driver type of vehicle too, so driveability is very important to me. The only complaint so far is that it doesn't always start on the first crank, sometime I have to crank it again. But I'm sure that's tunable. Once it's started though, I can't tell a difference from the previous non-scaled tune.

[GraphiteSRT]

Not that is affects the driveability of the car but the loss of resolution down low is somewhat bothersome. With it scaled 50% the spark table is now doubled and I get no where near the end of the table.

I found some 120lb injectors that may just be what I need to avoid fudging the stoich afr

[5_Liter_Eater]

Divide your IFR by some number, and multiply the stoich AFR by the same number.

Example... Your injectors flow 80lb. Divide that by two, and multiply stoich so it says 29.4.

Jez this is the first I've heard of this (scaling stoich). So all the complicated scaling we've been doing for years is now obsolete? Beauty idea.

[DSteck]

The stoich trick doesn't address airflow limits.

[5_Liter_Eater]

Yea but with an E40 speed density tune that doesn't matter. Still not sure I get it though; So I have 100 #'ers, if I was starting off with a stock tune with 33# injectors I would just triple stoich and thats it?

[5_Liter_Eater]

Of course stoich only goes to 32:1. I guess thats why you use an IFR of half of your injectors and just double stoich.

[gn2beatu]

Did someone recently post something about the E40 having an issue with the easy way (cut IFR in half and double stoich) or was that another ECM?

[DSteck]

Yea but with an E40 speed density tune that doesn't matter. Still not sure I get it though; So I have 100 #'ers, if I was starting off with a stock tune with 33# injectors I would just triple stoich and thats it?

The E40 still hits an airflow limit in SD. At least the blown TBSS I worked on did. No matter what, it would lean out until I scaled it.

[5_Liter_Eater]

Well shoot. E40 strikes again.

[GNXClone]

Scaling the entire calibration by 50% instead of the Stoich AFR table has been working great for my setup, even with an E40.

The only real issue I had was with cold and warm cranking. Setting the "Cranking VE vs MAP vs RPM" to 65 versus 100 helped. I also modified "FA Mult Stage 1 vs Time". Most of the time, it would start on the first crank, but not always. Occasionally it would stumble and die. Other times it would crank and crank and finally catch.

Then I stumbled upon a trick. I leaned out the Primary VE cell at 400 RPM / 105 kPa, and it starts each and every time now, on the first crank, cold or warm, gas or E85.

There's no other time this cell even comes close to being referenced except during cranking, so it does not affect normal driving.

[jakebdb56]

Nice. The Cranking VE must be scaled whether III/IV to get cranking correct. Sometimes when vehicles have problems throwing the MAF codes at cranking I'll have a scaled MAF value at the first cell in the MAF tables to help with cranking if they just replaced a battery or something that would cause the codes to clear.

[DSteck]

Cranking VE bit me the first time I scaled a tune... I couldn't figure out why it started like hell until I finally realize it. Backed it down the same percent, and all the sudden it was fine. D'oh.

[backchannel]

Divide your IFR by some number, and multiply the stoich AFR by the same number.

Example... Your injectors flow 80lb. Divide that by two, and multiply stoich so it says 29.4.

This req' PE x the same stoich factor?

[DSteck]

No.