staged injection

whatsup guys , looking to get some opinions here

im busy building a forged Nissan ca18det engine

so i have been thinking for some time about doing a staged injection setup with 8 injectors,

but here the kink , i want to run dissimilar fuels , doing a pump gas tune on the first set of injectors 440's

and then E85 on the second set of 800's

has anyone done this ?

planning on using a haltech elite , is this possible to run different duty cycles etc on different injectors etc ,

anyone with more info please do speak up

What's the purpose of two fuels though, are you going to run two seperate fuel tanks?

Seems like unnecessary weight and a lot of extra complication (potential points of failure) in your fuel circuit.

I'm using staged injection with a Link ECU, using 440cc inboard and 1000cc outboard on an NA setup.

You'll need 8 independant injector drivers + the ability for the ECU to control them in a meaningful way.

In my case, the outer injectors start at approx 5500rpm (just after a major harmonic in the intake manifold) and graduate towards 95% outer injectors 8000rpm onwards.

For your case I would think it's a better option to run a flex fuel sensor and then just fill up with E85 when at the race track or whatever and then just fill up with pump gas when you're finished.

The new GP packages for the MoTeC M1 have this functionality built in. You can download the package from here and open it in M1 Tune to look at the functionality.

the reason im looking into this is because here in south africa E85 is not yet available at the pump , with flex fuel precise control cannot be achieved unless the fuel tank is drained and filled with e85 , yes i do plan on running a seperate fuel cell , with an added fuel pump , using this method i believe one can achieve the perfect fuel mixture by the flick of a switch thus having a 800cc shot of E85 available at any given time , which is added onto the 440'cc of pump ,

so say for instance you are at the track /drag strip you can achieve the best possible fuel mixture without having to drain fuels , take fuel with you to the track etc

If you are able to get your hands on E85 then I would invest in a ethanol content sensor, tune it on pump fuel, drain the tank, fill it with your E85, check the true content with the sensor and tune it to suit, the more you tune on E85 the less pump gas will be in the mix and then you can just mix the fuel in tank and the flex fuel system will take care of the middle ground.

Andre covers the theory and practise of E85 and flex fuel in a couple of recent webinars:

https://www.hpacademy.com/previous-webinars/076-tuning-for-e85-motec-m150/

https://www.hpacademy.com/previous-webinars/077-flex-fuel-tuning-link-g4/

Running 2 fuel systems will be totally counter productive in the long run because of the extra weight involved, if you were after a shot of extra power I would probably choose nitrous, the system would be a lot smaller and lighter.

Right now the only ECU I'm aware of with this sort of dedicated functionality is the Motec M1 as mentioned by BlackRex. It would be possible to get the Elite to run this sort of system but you'd need to fudge the parameters to get a VE map that still looked somewhat meaningful as the ECU can't account for the different fuel characteristics. Alternatively I guess you could get a similar result by fudging the injector flow data for your secondary injectors. Neither option is particularly nice but probably workable.

In the past I've set up a couple of dual fuel cars, albeit just so we could switch between pump gas and race gas easily without draining tanks. It's a pretty big job and you need to factor this in along with the expense.

thank you gentleman for your inputs , i have decided only to go with the 800's and flex setup and see whether ill max the injectors out before i get to my performance goals ,then ill just upgrade to a 1200cc

Hi guys.

I was planning this setup with a link G4+ thunder.

Running an oe injector for primaries and bigger injectors as secondary with e99 in secondary and pump 91 in primaries.

E85/99 isn't available here and I'm not looking to be power limited but I also don't want to rip through the ethanol because it's a 4 hour drive to get more.

My original rhought was to tune the car onlow boost up until 90% duty cycle and then stage the ethanol secondaries in with them goingquickly to total fuel control at whatever map pressure that end up being.

Willthere be issues with air/ fuel monitoring?

Has anyone tuned a setup like this with dual fuels that would have insight into other complications I may be faced with?

With the staging on the G4+ this is controlled via MAP rather than IDC. There's probably a few ways that you could achieve the results you want. My first thought would be to run a boost level that will allow you to run solely on the primary injectors for most of the time. You could then use a digital input to trigger a higher boost set point and also enable the second fuel pump. you could then stage in the secondary injectors.

The fuel and ignition timing maps are going to look somewhat unusual but there's no real way around this. You would want to ramp up the timing and potentially boost as you stage more ethanol injection in and hence the knock resistance increases. Without a specific dual fuel capability there is probably the potential for engine damage if you're not very careful with the configuration and tuning of this system. In particular you're going to need a way of monitoring the fuel level in the secondary fuel system as running low could be a potential disaster.

Thanks Andre. I will be doing more research into the system and how to get it to work with this as a very good starting point.

Im not sure how Link does it at the moment but I know something like a second ignition and fuel map similar to how the Honda VTEC k series uses would be optimal I would think in that I could run my low map (base injectors) with optimal fuel and timing and when on the "vtec" map with the ethanol injectors you could run it with higher timing throughout so that the timing isn't an abrupt increase?

Noted on the engine protection strategies. I will add that to my list of things to consider an output for.

You could run a second fuel and ignition map on the G4+ with no trouble but there won't necessarily be a defined cut over as you will be staging the secondary injectors in relatively slowly. This would mean for example you can't make a dramatic jump in timing right away.