Feature Request thread ( make sticky )

This section is dedicated to discussion of DTA engine control units such as the DTA E48 EXP, P8 Pro, DTA S40, S60, S80, and S100, as well as all things ECU related.
rjwooll
Posts: 81
Joined: Wed Jan 28, 2015 5:42 am
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75

Re: Feature Request thread ( make sticky )

Post by rjwooll »

Rob Stevens wrote:Are you adding any air or just expecting it to start on fuel and little air. My own car has no air valve and does require you to open the throttle a little whilst cranking when at -10 or so. I think I use something like 400% enrichment for the first few turns.

However don't forget that the injection pulse is caped at 40ms by the software, I only found this by measuring.
I do use the throttle when starting to increase fuel delivery and add air. Like you I have no idle air valve. Thanks for your comment about the % enrichment you use which is the same as mine (below 0c and for 10 turns), and the limit you discovered on the injection pulse. I see that 40ms is also the limit set on the injector start pulse.

Assuming I use a bit of throttle when starting, 400% enrichment delivers about 20ms injector open time. The start pulse is set at 15ms so I'll start by increasing that to 25ms and increase the enrichment to 500% for the first 4 turns.

Thanks again, Richard
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Feature Request thread ( make sticky )

Post by Alex DTA »

It is difficult to get right, and takes time, there's no way around that unfortunately.
As you say, it's very difficult to repeat the test as things warm up so quickly once running.

As an example, my car only has 53% extra fuel for the first 20 turns, and it starts on the key, no matter what the weather (as long as I have remembered to charge the battery).
It has no idle valve, so the throttle body is slightly open, and the idle controlled with ignition timing.

What engine is it? I'll see if I can find anyone that has a similair engine.
rjwooll
Posts: 81
Joined: Wed Jan 28, 2015 5:42 am
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75

Re: Feature Request thread ( make sticky )

Post by rjwooll »

Alex DTA wrote:It is difficult to get right, and takes time, there's no way around that unfortunately.
As you say, it's very difficult to repeat the test as things warm up so quickly once running.

As an example, my car only has 53% extra fuel for the first 20 turns, and it starts on the key, no matter what the weather (as long as I have remembered to charge the battery).
It has no idle valve, so the throttle body is slightly open, and the idle controlled with ignition timing.

What engine is it? I'll see if I can find anyone that has a similair engine.
Thanks Alex - t's a Lotus 912 HC engine (in a 1981 Lotus Elite) but I think I know or know of most people with a similar engine plus DTA (via Lotusbits). I think those other owners might be able to use whatever I come up with. The starting problem only really exists below 5c, otherwise it starts fine.
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Feature Request thread ( make sticky )

Post by stevieturbo »

Basics.

Ensure engine has enough air to start under such conditions.

Then start with less fuel, and add as required to enable quick starting
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
ECU Model: S100 Pro

Re: Choke

Post by gnutz2 »

rjwooll wrote:Given the difficulty of setting up reliable cold starting with the ECU (because it's so difficult to run repeat tests as once the engine starts it starts to get warm) could a manual choke option be introduced? The choke would be connected to a throttle pot and feed into an aux input on the ECU. The position of the throttle pot would control the % overfuelling, with a maximum of say 200% increase (=3 x normal)

Not a major problem for most on here I know, but for those of us running road cars cold winter starts can be difficult and it requires quite a lot of trial and error to set up the cold start table correctly.
Wire up a potentiometer into any of the analogue inputs, set the fuel modifier from 0 to 200% or whatever you want and you have what you describe. You can also set the secondary input to water temp, say 50c and disable the function above that temp.
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
ECU Model: S100 Pro

Re: Feature Request thread ( make sticky )

Post by gnutz2 »

I've got a really jucy feature here 8-), ok I stole the idea from another manufacturer.

Instead of 2 separate fuel, ignition and boost maps. How about a blending pot between the two maps.

Put a rotary cal switch on the dash and you have 12 different maps (albeit in a linear fashion but better than nothing)

:D
stevieturbo
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ECU Model: No ECU
Location: Norn Iron

Re: Feature Request thread ( make sticky )

Post by stevieturbo »

I guess playing with the flex fuel sensor input could do similar ?

Although that's a strange way to do things if another brand is doing it !
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
ECU Model: S100 Pro

Re: Feature Request thread ( make sticky )

Post by gnutz2 »

stevieturbo wrote:I guess playing with the flex fuel sensor input could do similar ?

Although that's a strange way to do things if another brand is doing it !
Good idea, I guess you could see the fuel flex input as another analogue input with fuel and ignition modifiers, the main thing that bugs me about the fuel flex is the absence of a boost modifier, which means you have to manually lower/raise the boost pressure depending on the ethanol which defeats the point of it! The whole point of ethanol is more boost!

looking at the wiring diagram the e85 input looks digital! does this mean the fuel flex sensor calculates ethanol based on duty and frequency?

Blending 2 maps is defiantly a work around way of getting more maps but is much more flexible than just having 2 maps.
gnutz2
Posts: 190
Joined: Tue Jul 03, 2012 2:33 am
ECU Model: S100 Pro

Re: Feature Request thread ( make sticky )

Post by gnutz2 »

While we're on with boost modifiers, we need a boost column in all the ana/aux functions. I run a dry nitrous system through aux3 which requires the fuel and ignition changing, it also need the boost lowering which has to be done manually.

Cheers Baz :D
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Feature Request thread ( make sticky )

Post by stevieturbo »

True enough, yes the commonly used sensor is digital. I believe frequency indicates ethanol content and pulse width temperature or visa versa.

Although I think there are some analogue sensors available.
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