5th injector to run E85?

[shelbycsx4me]

Good Day!

I've been kicking around an idea of running e85 in my 89 CSX.
My thought is to add a 5th injector that I could switch on
when I have a full tank of Corn-Power :evil:

Getting fuel to it is not an issue, put powering/pulsing it is.
I do not want to burn up the SMEC injector drivers if I
tap into #3 or #4. I've seen plans out on the internet
about building circuit board transistor driver that takes
a signal from the harness.

Do anyone have a link or plans for a triggered injector
driver ?

Steve

[contraption22]

Simplest solution would be 4 larger injectors and a custom tune.

I think trying to supply the required fuel through one 5th injector would create problems with uneven fuel distribution.

[bakes]

i recommend to get ShelGame to make you a 4 play chip made with 4 different cal 2 for stock fuel and 2 for e85 the just turn the switch as needed.

[Ondonti]

Bad idea? There is a reason so many motors blew up back in the day without making much power.

[MILKCARTON]

I ran a cold start injector on my Shelby Lancer for 3 years/ with +40's at 23 psi boost with never an issue. I was controlling it with a snow performance meth injection controller. They work variable with a low psi setting and a max psi boost setting and builds a ramp between the two. I put the injector in the intercooler line right before the throttle body next to the meth nozzle. I know this aint a perfect set-up and everyone will talk sh*t about it but it worked great. The car made 230 fwhp here at 5800 ft altitude and I beat on it here for a long time with no issues, so take it for what it is worth.Of course there are much better ways to do this, but this worked for me on a budget.

[contraption22]

Many have had success runing 5th injectors for small increases in gasoline flow to compensate for inreased boost levels. While crude, these systems have worked.

But the original poster will have to increase his fuel volume over 30% just to maintain the fuel demand of an otherwise stock TII.

That means this 5th injector would have to flow more than any one of the primary injectors.

Trying to dump that much fuel into your engine via an extra injector, and hoping to get somewhat even fuel distribution through an intake manifold designed for port injection is way too risky IMHO.

[MILKCARTON]

Agreed, I was running meth injection also to help cover up for the +40's but I am at altitude also so wasnt really that far off afr at full boost was 11.4, but yes you are crossing your fingers that something doesnt stop working.

[shelbycsx4me]

Ok.
Will i get the same o2 reading with e85 as regular fuel and
won't the computer make some adjustment to the injector
pulse width if it's in the 'sweet spot" range of the o2?

[contraption22]

The computer does the ability to manipulate pulse-width to maintain a stoich a/f ratio at part throttle and light loads using data from the 02 sensor. I don't think it has nearly the capability to compensate for the increased fuel volume needed to run E85. Once you go WOT, the computer ignores the 02 sensor and fires the injectors based off pre-set tables.

[shadow88]

Also, don't forget it's an oxygen sensor, not a fuel sensor. Maybe with an adjustable fuel pressure regulator, you could add the required 30% (???) more fuel.

[tryingbe]

89 CSX uses SBEC, not SMEC

[tkelly27]

I run E85 and you're going to save yourself a lot of headaches by running a flip chip or chips you've burnt yourself.

As mentioned running 1 extra injector to give you 30% more fuel isn't really ideal, especially when it can't be distributed to all 4 cylinders and that you don't know how you will drive it. Furthermore, this will only bring you back up to the capabilities of 32pph injectors.

Bumping the fuel pressure is a bad idea too.
http://www.rceng.com/technical.aspx

(new fuel pressure/old fuel pressure)^-2 * old flow rate = new flow rate. To get 30% extra new flow/old flow = 1.3.

1.3^2 = 1.69. That times the old base pressure of 55psi is 1.69*55 = 93psi. That's at your base, run 20psi and you're up to 113 at the regulator, easily 120 at the pump. You're going to need 2 Hp whinebros to keep up with that. Assuming your fuel injectors were still opening at that fuel pressure, you're still going to be limited to stock T2 hp. You would still need a 5th injector just like you would with gasoline.

You should choose D, and create the G-child. I got a set of 550cc DSM injectors for doing work for a friend, I'll be getting a set of 880's for $100 from another friend. Both of these are way bigger than +40's. The 550's at 55psi base pressure work out to 65pph. I burnt a chip for myself, ran around on gas, filled up on E85, swapped the chip, and I've not looked back. It takes time, money, and effort, but if you want to go with a different fuel, or make power beyond the stock map sensor, it is the best way.