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CDAN4 Injectors Slopes

Unread postPosted: Thu Sep 28, 2017 4:31 pm
by galaxis
As far as I can tell from personal experience and from reading online, CDAN4 ecus don't appear to handle large injector slopes properly.

Here's my situation:
Cobra 39# injectors & 90MM LMAF
4.6 2v PI heads with SVO supercharger CDAN4 BE2012 Sailorbob strategy

No matter how high I set the slopes in my calibration, my car runs ~20% rich unless I change my MAF flow to account for it. I know that a stock LMAF transfer likely won't be perfect for me, but being pretty consistently 15-20% off across the board seems suspicious.

The other cue to me that changing the MAF is lying to the car: my load values are lower than I expect. With no blower, stock injectors, and multiple different MAFs I used to see somewhere around 95 MAX load in a pull on a good day. Now I see somwwhere around 90 load at like 7psi of boost; my 0 boost 0 vac load is around 65.

I have NO other scaling in my tune (my displacement parameter is my ACTUAL displacement, etc.)

As far as I can tell, the SCT tune I have also does this.

I guess I just want to make sure I'm following 'best practice' and not missing a better solution.

Re: CDAN4 Injectors Slopes

Unread postPosted: Thu Sep 28, 2017 8:23 pm
by decipha
yea the clockconversion clips the max slope value on all eec Vs

when i get to my laptop i can tell u the exact value

best to scale it in half i always do

Re: CDAN4 Injectors Slopes

Unread postPosted: Thu Sep 28, 2017 8:41 pm
by galaxis
Okay it just clips it at some point?

So if you scale everything down enough, it brings your injector slopes back into the non-clipped, valid range of adjustment...
And 50% is easy to work with.

I think I'm definitely going to give this a try; thanks

Re: CDAN4 Injectors Slopes

Unread postPosted: Fri Sep 29, 2017 4:38 am
by sailorbob
The CDAN4 injector size limit is 40.23 lb/hr.

Re: CDAN4 Injectors Slopes

Unread postPosted: Wed Oct 04, 2017 5:15 pm
by shine1stang
sailorbob wrote:The CDAN4 injector size limit is 40.23 lb/hr.


so the values higher than 40.23 aren't recognized by the ecu? are we talking about Alosl injector low slope? I have mine set to 101.46 the 80lb value. Ive got a pretty good running tune on my car and have taken a few wot rips since going with the qh. all seemed well though

Re: CDAN4 Injectors Slopes

Unread postPosted: Wed Oct 04, 2017 10:18 pm
by decipha
correct, the ecu cant calculate a slope that high, anything above 40 will return the same value that the ecu uses

yea all will be well, u can dial in anything, but if u want the true injector values in there youll have to scale it back

on cdan4 i always divide the injector values and maf by 3 to get it under the max slope

Re: CDAN4 Injectors Slopes

Unread postPosted: Thu Oct 05, 2017 12:05 am
by motorhead1991
Taking notes, since I'll have to do this on FLH2 as well. Perhaps that's why I had o pull so much from the offset table...

Re: CDAN4 Injectors Slopes

Unread postPosted: Thu Oct 05, 2017 1:36 pm
by shine1stang
decipha wrote:correct, the ecu cant calculate a slope that high, anything above 40 will return the same value that the ecu uses

yea all will be well, u can dial in anything, but if u want the true injector values in there youll have to scale it back

on cdan4 i always divide the injector values and maf by 3 to get it under the max slope


will i have to scale anything else? just high/low slope and maf? Or should i just scale everything>vlt offset, breakpoint,displacement ect?

Re: CDAN4 Injectors Slopes

Unread postPosted: Thu Oct 05, 2017 1:39 pm
by decipha
the offset isnt affected by scaling leave it be

u have to scale the breakpoint though

if the engine is going to be making a lot of boost then leave sarchg be and scale perload (fn035) and the spark table load scaling, otherwise, scale sarchg down too