Does somebody use twin injectors settings?

Give input on tuning as well as any tips and tricks you may have. Also feel free to share base mapping files for various engine types.
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: Does somebody use twin injectors settings?

Post by Rob Stevens »

It must bring the 1st set on line if its run out of duty on the 2nd, would seem silly to run out of fuel if you have twice the capacity available. Like I say I'll ask Allan how it copes in this situation next time I see him. I doubt it would be 100% on one set and the balance on the other set as it will be hard to map unless the dead times were bang on trying to deliver say 2% of the duty.
Allan did tell me that the injector never runs at 100%, there is always a pulse.
All this is of course of no concern if you can run on 1 set alone.
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Does somebody use twin injectors settings?

Post by stevieturbo »

When there were no user defined changeover parameters, the change happened as per DTA's instructions.

The only reference in current instructions is "Note that if either injector becomes open for 100% of the time any balance required will be transferred to the other injector."

But all these queries are why I set my blend map under load from a lowish rpm to 50/50. The load will be evenly split over both injectors at all times when it actually matters.
Rob Stevens
Posts: 1247
Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: Does somebody use twin injectors settings?

Post by Rob Stevens »

Thanks, last thing I'd do is read the book! LOL
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Does somebody use twin injectors settings?

Post by stevieturbo »

I dont normally myself...but it has an index for quick reference lol. Sometimes it is worth taking a look !
katana
Posts: 455
Joined: Sun Jan 27, 2013 6:08 pm
ECU Model: S60 Pro
Firmware Version: 29

Re: Does somebody use twin injectors settings?

Post by katana »

Rob Stevens wrote:Mmmm Methanol but only on 650cc injectors, one up stream for charge cooling, biggest drop in ones I could find. 450bhp 1300 bike engine.
Just got to know where to look................and they ain't the biggies! 8-)
http://www.rceng.com/Peak-Hold-Injector ... P11C5.aspx
Seriously though the SSB boys are using upto 1600cc injectors x 4 with gasoline and upto 700hp from Busa's and they still idle like stock! One nice side effect of alky though is that it loves compression & / or boost! I did push a set of 214cc Bosch injectors x 8No to 370hp - that was being silly though! :lol:

Back to the original question though and this probably won't help but the Motec system works on the primaries until the defined blend point then it utilises both injectors but halves the pulse width on each so it might go from primary @ 100% of mapped cell value to 50% to both in next mapped cell value. This way allows big injectors to still run clean down low and keep the max duty over both injectors at reasonable level. ;) + if you reach max number for mapped value upping the %'s of each injector effectively richens the whole map up where the increased percentages are allowing the map numbers to be reduced but still flow more fuel.
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Does somebody use twin injectors settings?

Post by stevieturbo »

katana wrote:
Rob Stevens wrote:Mmmm Methanol but only on 650cc injectors, one up stream for charge cooling, biggest drop in ones I could find. 450bhp 1300 bike engine.
Just got to know where to look................and they ain't the biggies! 8-)
http://www.rceng.com/Peak-Hold-Injector ... P11C5.aspx
Seriously though the SSB boys are using upto 1600cc injectors x 4 with gasoline and upto 700hp from Busa's and they still idle like stock! One nice side effect of alky though is that it loves compression & / or boost! I did push a set of 214cc Bosch injectors x 8No to 370hp - that was being silly though! :lol:

Back to the original question though and this probably won't help but the Motec system works on the primaries until the defined blend point then it utilises both injectors but halves the pulse width on each so it might go from primary @ 100% of mapped cell value to 50% to both in next mapped cell value. This way allows big injectors to still run clean down low and keep the max duty over both injectors at reasonable level. ;) + if you reach max number for mapped value upping the %'s of each injector effectively richens the whole map up where the increased percentages are allowing the map numbers to be reduced but still flow more fuel.
Those are not big, and P&H are not directly compatible with DTA. ie you need resistors or a driver box. And RC are nowhere near as good as the Injector Dynamics stuff.
katana
Posts: 455
Joined: Sun Jan 27, 2013 6:08 pm
ECU Model: S60 Pro
Firmware Version: 29

Re: Does somebody use twin injectors settings?

Post by katana »

Don't go off the deep end! It was only an example that bigger ones are available!
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Does somebody use twin injectors settings?

Post by stevieturbo »

katana wrote:Don't go off the deep end! It was only an example that bigger ones are available!
I know

But likewise, I'm also using 600cc injectors x 16 because at the time when I put mine together no decent larger ones were available.
I had previously used 8 x RC750's and TBH they didnt offer any more flow than the 600's in real terms, and they were much harder to tune. Batch fire probably doesnt help...too lazy to add a cam sensor. But I'd struggle to recommend the RC's based on past experience compared to better performers like Siemens, Bosch etc.
But back then, there simply werent any decent large high impedance injectors, so 2 in per cylinder was the obvious choice.

Yes there are many many options available these days, but not everyone wants the expense of replacing stuff.
welshpug
Posts: 130
Joined: Tue Sep 06, 2011 4:53 am
ECU Model: S40 Pro

Re: Does somebody use twin injectors settings?

Post by welshpug »

i guess its not as important to you guys running boost, but on an n-a twin injector setup the switching point is quite important as it can affect torque and power delivery quite dramatically especially with very wide rev range and fairly wild cams.

though granted, twins are not used in these applications typically for the same reasons as boosted engines, often they use smaller injectors to achieve a higher degree of control
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Does somebody use twin injectors settings?

Post by stevieturbo »

Whilst it seems you can "switch" from one set to another. In general that isnt the ideal way to do it.

the blend map is there to help make the secondaries coming online a smooth process. The secondaries are just there to supplement the primaries. Switching from one set to another is likely always going to have a difficult transition.

But using both injectors, the system should work seamlessly and you'd never know two sets are being used.

One major advantange of twins is so you can still use small injectors for that fine control, but still have plenty of fuel available because you have two of them.
Post Reply