CharlieUK

I was reading on the Aquamist site that the FD3s by design dumps fuel to aid with coolingor something like that (perhaps I read it incorrectly), so if you are using AI with water, would the engine still need to "dump" the fuel.

I'm guessing if it didn't dump fuel anymore then the engine would be more economical?

CharlieUK

come on guys, I was hoping that some clever person would be able to give their opinion, that's why we're here afterall. Please.

WaachBack

iTrader: (21)

Yes you can lean it out some if you are running ENOUGH water. Usually at least a 10% water to fuel ratio. I am running 12 A/F at 23psi on pump gas with 550cc water.

Turblown

iTrader: (12)

I have been up to 19psi at a 12AFR, I was scared to go any farther in the power at that AFR( engine made of almost all new parts)... Managed 20+passes like that..

I recently took another car to 450rwhp @ leaner than normal afrs too, only 300cc of water...

WaachBack

iTrader: (21)

Ive been on 18psi with 300cc water and 12 a/f before with no knock.

20psi no water injection at 10 A/Fs is worse then 25psi 12 A/F's with 500cc water. When you break it all down, 3% water to fuel ratio makes up for one whole point of A/F when leaning from 10-12 A/Fs.

Thats why I tell people run at least 10% to be on the safe side. Im running about a 12% ratio, I believe Brent is too.

CharlieUK

so, there's no way that you can stop the FD "dumping" fuel then?

Liborek

WaachBack perfectly answered your question. If you want straight answer, Yes. Leaning out the mixture will lower specific fuel consumption.

There are many ways you can change AFR and water to fuel ratio.
http://www.riceracing.com.au/resourc...rinjection.pdf

This report clearly indicates, that they run as much as 1.5 water to fuel ratio at 16.5 AFR at 60 in.Hg absolute. In this case, best knock suppression was at lean mixture...
It seems, that higher water to fuel ratio and boost they run, leaner mixture was best for knock suppression and power. At lower water to fuel ratio, best permissible power was around 10.5 AFR, with no water even more towards 10:1, then detrimental...

CharlieUK

ok, from what I can see, the FD runs very rich as to aid in the cooling procedure, now it doesn't need to use so much fuel because it is running with AI, so I'm guessing that it would be ok to lean the fuel quite a lot as now there is no need for the extra fuel to cool the combustion chamber?

Liborek

You probably know answer.
Internal combustion engines are very interesting stuff, simply saying yes or no would be vast generalization... That extra fuel isnīt cooling mixture-to the point yes, but this isnīt what prevents detonation. Fuel molecules physically prevents infrared rays(which travels at speed of light-much faster than actual flame front)from combustion initiated by spark from reaching far end of combustion chamber before actual flame front reach it-but to much fuel will again increase detonation possibility...

Read the report what I posted-many things to learn.
Also something here http://www.fipswaterinjection.com/te...tsreports.html

_Bahrx7_

iTrader: (8)

So what your saying is that you were able to pull fuel and get your AFR's into the 12.xx with just the use of water?

-What was your knock/EGT's like?

-Did you notice a big difference in power between rich AFR's and no water vs. lean AFR's and water?

-Did you play with timing at all, or just pull fuel out?

WaachBack

iTrader: (21)

Yes.

No EGT gauge. Knock is in the 20's.

Yes, no actual dyno numbers (no dyno on my island) but you can feel it.

Timing is 12 advance at 23psi, which is mildly safe.