Sequential and twin injectors.

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Borla
Posts: 51
Joined: Mon Mar 20, 2017 2:41 pm
ECU Model: S80 Pro

Sequential and twin injectors.

Post by Borla »

Hi all, have quite a few questions about getting the base map configuration right. I've looked through the manual and searched these forums but haven't found the answer to what I'm looking for. This is for a BMW S1000rr, but is relevant for anyone wanting fully sequention injection. Engine has cam sensor.

Below is a screen shot of the sequential injection window as on the base map supplied.

https://www.flickr.com/photos/153762396 ... res/2Jj5C7

So next step is to tick the sequential box, but what next, do injectors 5, 6, 7 & 8 have to mirror the offset that 1 to 4 are set to, ie 0, 180, 360 & 540.

I have looked at the three other bike engine base maps supplied and none have the sequential and twin injectors set up.

Thanks for any help.
Last edited by Borla on Sun Apr 16, 2017 4:54 am, edited 1 time in total.
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: Sequential Injectors.

Post by Rob Stevens »

Im not sure how the sequential works with twin injectors, even if it does it would be next to impossible to find out what the engine would like? Different timings on each of the twin injectors via the trims?
Borla
Posts: 51
Joined: Mon Mar 20, 2017 2:41 pm
ECU Model: S80 Pro

Re: Sequential and twin injectors.

Post by Borla »

Thanks for the reply, I thought I'd start throwing some questions onto the forum so I didn't need to keep bothering Alex in the office, there must be people that have done this before.

From reading the manual I thought the trim function was to modify each injectors output to account for mechanical differences (eg different tract lengths)?
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: Sequential and twin injectors.

Post by Rob Stevens »

By trim I meen the firing angle for each injector in the same window as the adjustment +/- of the pulse width
Borla
Posts: 51
Joined: Mon Mar 20, 2017 2:41 pm
ECU Model: S80 Pro

Re: Sequential and twin injectors.

Post by Borla »

Ah, ok I follow.
katana
Posts: 455
Joined: Sun Jan 27, 2013 6:08 pm
ECU Model: S60 Pro
Firmware Version: 29

Re: Sequential and twin injectors.

Post by katana »

Surely (bear with me as this experience is with 8 sequential injectors and a MoTec M8) the injection angles will be the per cylinder primary and secondary injectors ie 180 360 540 and 720 then they will be 'fine tuned' for injection point by cylinder. Mine ran 4 primary sequential which blended into the 4No. secondaries across about 2000rpm and against MAP load. The secondaries didn't add to primaries, the primaries backed off and secondaries added what was dropped. It wasn't a one point switch though - more like percentages 25 / 50 / 75 / 100. Wish i'd put the bigger injectors in, in the fist place as we max'd out the smaller ones, got a number and sort of lost interest - i'll revisit it one day now it has 50 odd % more flow capacity.
stevieturbo
Posts: 3578
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Sequential and twin injectors.

Post by stevieturbo »

I dont think you have any control over secondary injector timing ? Whatever is applied to primaries is applied to secondary ?

In general most say to have end of injection prior to the intake valve opening.

Although really if you want to fine tune or optimise for your setup...dyno time is really the only answer.
Although surprising such an engine uses 2 inj per cylinder ? Is that common on production bikes ?

Is there any info on how they use them ?
Borla
Posts: 51
Joined: Mon Mar 20, 2017 2:41 pm
ECU Model: S80 Pro

Re: Sequential and twin injectors.

Post by Borla »

I was under the impression that the secondary injectors completely take over on the standard ecu above a rev point to give the fuel more time to mix with the air. The primary injectors are in the standard place most are in on the intake side of the butterfly. The secondary injectors are mounted in the top of the air box pointing straight down directly into the intake, an idea borrowed from F1. It's not my video but you can just about see the bottom of the top injectors when the active velocity stacks are in the down position here;

stevieturbo
Posts: 3578
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Sequential and twin injectors.

Post by stevieturbo »

No they dont. The secondary injectors do whatever you tell them to do.

If you tell them nothing, they are there to supply additional fuel when the primaries can no longer cope.
katana
Posts: 455
Joined: Sun Jan 27, 2013 6:08 pm
ECU Model: S60 Pro
Firmware Version: 29

Re: Sequential and twin injectors.

Post by katana »

stevieturbo wrote:No they dont. The secondary injectors do whatever you tell them to do.

If you tell them nothing, they are there to supply additional fuel when the primaries can no longer cope.
Big assumption Steve especially as you don't know how or what BMW have actually done!

As the OP has stated, the inlet tract length varies with rpm and with injectors further from the valve it will improve mixing time at higher rpm. Getting 200bhp out of 1litre NA - BMW are doing something right and in racing that engine is over 240hp and probably 14+k rpm (whether that is with upgraded injectors is anyone's guess).

Your statement assumes two separate fuel maps - primary up to 'X' point then flat with secondaries adding a fully scaled map on top, turning on or off based on rpm / inlet tract variations. Why complicate a simple map with something other than blended dual injection or single point injection just further from the valve?

All operation is speculation but the results speak for themselves!
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