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Forum Admin
13-11-2003, 07:23 PM
I am curious to hear back from users what AFRs they are seeing after they have tuned their cars for water injection?

See the related thread on calibration but also curious what if any calibration was done on the lambda sensor with an exhaust gas analyzer or otherwise.

spool
03-03-2004, 02:23 AM
I have Derek devices.com kit.

I've tuned to 11.5 AFR and it pulls very hard on my '98 Supra TT BPU car.

It's a great system.

honki24
06-05-2005, 04:43 PM
a friend on EVOM said he leaned out to 11.4 on his EVO, AND added timing, as well as bumped up to about 22 psi.

tici
04-06-2005, 11:24 PM
With water alone it doesn't change (WB).
With water and alcohol (ethanol in my case) I saw lower AFR's - alcohol burns oxyges same as fuel.

themadscientist
16-07-2005, 01:49 PM
I just tuned my first WI WRX.
Tuned AFR is 12.5-12.8:1 I was able to add 4 points of timing, and the TD04 is blowing 20psi in the mid range tapering to ~16psi at redline without det. Next week I should have it on a dyno to try and lean it out even further and see if it makes more power. :D

TMS

tici
17-07-2005, 01:40 AM
I bet it won't : 12.5 - 12.8 is pretty good!
OK, I'm talking V8 engines, but I can't imagine that different engines are different about AFR.
I also tuned it with water alone exactly in the same range as yours, then switched to 50% ethanol (same quantity) and had the feeling the car was running better.
On the dyno I changed timing (from 17 to 23*) and AFR (up to 13.:1) but I saw no power difference, I guess there is an optimum.
Please let us know about the result, Im curious!

unior
28-07-2005, 11:30 PM
peak torque occurs at 13.2:1

best for turbo car is 12.5:1

according to RB racing that is

RICE RACING
09-12-2005, 08:18 AM
We dynoed a Toyota supra with auto gearbox and it made following

470rwkw on 11.0:1 AFR 12 deg timing 34psi boost
470rwkw on 12.5:1 AFR 12 deg timing 34psi boost
471rwkw on 12.5:1 AFR 18 deg timing 34psi boost

We have dynoed FSAE engines and made no difference in power or torque from 10.8:1 AFR to 13.9:1 and all ratios between. Some of the gains are over stated for pure power differences, all I have experienced over the years points to this especialy if you have a racing derived ignition system that is capable of firing the air/fuel mix regardless of mixture.

What you gain in BSFC you loose in total energy mass thrown into the engine (less fuel = less power) but its net effect is quelled by increased BSFC). If your ignition system is marginal then you can make big gains with running leaner more acceptable mixtures.

If fuel efficiency is not an issue (def not for street or sprint race circuit car) as time spent on WOT and high revs is very small percentage of duty esp on street than I simply set up cars with maximum fuel cooling rate even with WI as durability is enhanced, any marginal gains in power "and they are very marginal" running leaner mixtures are not worth the hassel unless your fuel system capacity is stretch (not enough injector) or as stated before you need "racing fuel efficiency gains for longer time on track to increase pit window etc.

I generaly use 10.8:1 to 11.8:1 in all applictions running pump 98 octane and up to 36psi boost pressure on 8.5 to 9.0 compression.

JohnA
09-12-2005, 09:02 PM
We dynoed a Toyota supra with auto gearbox and it made following

470rwkw on 11.0:1 AFR 12 deg timing 34psi boost
470rwkw on 12.5:1 AFR 12 deg timing 34psi boost
471rwkw on 12.5:1 AFR 18 deg timing 34psi boost

We have dynoed FSAE engines and made no difference in power or torque from 10.8:1 AFR to 13.9:1 and all ratios between....

My auto supra registered 5-7% more power just by trimming off fuel from the stock 10.5-11:1 up to 12.5:1
That was at holding 18psi on stock turbos.

Richard L
31-01-2006, 11:30 PM
I am curious about the product coming out of the exhaust pipe afe 10.8:1. Unless the content contains only "water", "carbon dioxide" and ""gasoline" and 0% "carbon monoxide" , I can then accept that there are no charge in power output.

As long as Carbon monoxide exists, there should be some loss in power since some oxygen is being taken away by carnon monoxide, yields only 30% power of Carbon Dioxide.

Richard

RICE RACING
01-01-2007, 02:40 PM
We dynoed a Toyota supra with auto gearbox and it made following

470rwkw on 11.0:1 AFR 12 deg timing 34psi boost
470rwkw on 12.5:1 AFR 12 deg timing 34psi boost
471rwkw on 12.5:1 AFR 18 deg timing 34psi boost

We have dynoed FSAE engines and made no difference in power or torque from 10.8:1 AFR to 13.9:1 and all ratios between....

My auto supra registered 5-7% more power just by trimming off fuel from the stock 10.5-11:1 up to 12.5:1
That was at holding 18psi on stock turbos.

the above was with racing modified hi output 500r autronic CDI box (it will fire anything) running elf racing fuel. autronic ECU set to throttle map mode so simple AFR program change (input new target AFR line) = instant perfect tune in that load site. it made little difference in that application........ though turbo was maxed out and cant count for other variables that may have influenced that particular result

nothere
01-01-2007, 08:32 PM
help me out, I would have though the low afr (11.)would have meant you needed more timing to compensate for the slower burn. Was timing automatically adjusted to make max power during each run?

470rwkw on 11.0:1 AFR 12 deg timing 34psi boost
470rwkw on 12.5:1 AFR 12 deg timing 34psi boost
471rwkw on 12.5:1 AFR 18 deg timing 34psi boost

JohnA
01-01-2007, 09:02 PM
What slower burn?
I very much doubt that the speed of burn is slower at 12:1 compared to 10:1

The fastest burn speed for gasoline tends to be around 12.5:1 (all else factors being equal)

RICE RACING
02-01-2007, 12:22 AM
help me out, I would have though the low afr (11.)would have meant you needed more timing to compensate for the slower burn. Was timing automatically adjusted to make max power during each run?

470rwkw on 11.0:1 AFR 12 deg timing 34psi boost
470rwkw on 12.5:1 AFR 12 deg timing 34psi boost
471rwkw on 12.5:1 AFR 18 deg timing 34psi boost

maxtiming at full power as listed on tests.

another example of timing was from a friend of mine in norway (frode) not sure if he posts here or not? but i gave him some proven parameters for setting up his WI and on pump gas.

he has a max spark lead of 13deg @ 580bhp level as recorded on engine dyno, advancing spark another 2 degree's only net'd 4bhp increase in power, afr from memory was 11.0:1 region??? from my years of experience and track data i know rotaries dont pick up any noticable gains with greatly increased spark lead (again application specific) but they do have a great tendency to deposit apex seals in the turbine housing if you go for what should work out of a text book ;) his EGT was 840 to 850deg c pre turbine too.

we have other cars here that dont run WI at all (i want them too!) and on C16 race fuel need to run 10.5:1 AFR to live @ 36psi and only use 10 to 12 deg of advance, cars hold records in their class and infact beat others with much larger engines (12a v's 13b & 20b !) run 160mph in 0-400m test.

nothere
02-01-2007, 02:03 AM
RR, oh, those results I quoted from your post were with water injection? I missed that. Were they with great quantities of water?


John, I don't always speak very clearly, chalk it up to a liberal arts education, I was trying to suggest that an afr of 11 should burn slower than 12.5. So I think we are in agreement.

RICE RACING
02-01-2007, 07:30 AM
the supra ones are on stright racing fuel (no WI)

frode's are with wi ;)

I will have my new project ready in a few weeks and hope to add some more info

RICE RACING
13-09-2007, 02:44 AM
RR, oh, those results I quoted from your post were with water injection? I missed that. Were they with great quantities of water?


John, I don't always speak very clearly, chalk it up to a liberal arts education, I was trying to suggest that an afr of 11 should burn slower than 12.5. So I think we are in agreement.

Had some other example which I forgot to post up

RX2 making 578rwhp@21psi~18psi 13B running probably WtoF ratio (cant disclose exact amounts but its *high*) depending on zone in map, AF 9.8:1 to 10.1:1 Excellent power on this richer setting and not much diff to running less rich (11.2:1 or 11.5:1).

When you run leaner even with WI ratios of a higher amount you will not be able to run as much manifold pressure on normal 98 oct pump fuel (which we only use, no dyno race fuel queens alowed) which wont give you as much power either obviously.

I always run towards richer ends pretty rare to ever use some figures stated by others unless its on a car not making much power and there is more than enough cooling capacity and fuel quality to allow such things.

JohnA
13-09-2007, 09:12 AM
Could it be that fuel atomisation is degraded at high boost levels, so running richer mask this up?
I'm just speculating here (wildly!), but if boost pressure were very high, maybe some of the air would be moving too fast for the fuel to spread so we end up with rich layers and pure air layers.

Running richer might help shift this imbalance perhaps.

...or are the rotary inlet ports totally different?

RICE RACING
13-09-2007, 03:59 PM
Could it be that fuel atomisation is degraded at high boost levels, so running richer mask this up?
I'm just speculating here (wildly!), but if boost pressure were very high, maybe some of the air would be moving too fast for the fuel to spread so we end up with rich layers and pure air layers.

Running richer might help shift this imbalance perhaps.

...or are the rotary inlet ports totally different?

when I was doing thermodynamics my teacher did say to be that the rotary engine does have a higher index in the area of the curve in the PV diagram prior to igniton which gives higher values in those calcualted conditons during compression phase need to look through my old lecture notes but a vlaue of 1.4 v's 1.3 comes to mind (13 years ago now lol) ....... practical impact I dont know can only theroize.

The decent lab tests i have seen on either reciprocating or rotary engines boosted all do not show massive drops in IMEP as those would have you believe on the plethora of inernet tuning expert sites nowadays (even when tested down to 8.5:1 AFR's) so go figure??? I know from some decent references i have (re racecarengineer) of turbo cars, lots of those in pre fuel rationing ranup to 60% excess fuel ratios ! so another validation of the rich mindset and a necessary one to make engines live and make *maximum?* power......... if not efficeint in fuel usage terms ;)

I think the thing with water as shown in lots of older tests is that it is so good (so long as used in sufficient qty), in my tests thus far anything under 20% water to fuel ratio still benifits in very rich AFR's without the biglosses in power asuming you have a decent igniton system to do the job at hand, and sadly most do not have anything of the sort & probably is the single biggest reason for the abnormal losses of power at these rich settings? thoughts????

RICE RACING
14-09-2007, 02:37 AM
What I meant to say to clarify the above is that rich *insert figures* gives maybe 5% drop in power BUT allows 10% increase in IMEP (through extra boost ability, while things staying under less thermal stress despite extra power) so you end up with a net gain of 5% more power...... but I'm sure you kinda got what I was on about, just for the benifit of others ;)

and the richness factor is still very important when dealing with relativley small qty's of water to the fuel volume......... hence why I still run the way I do, given the fuel being the biggest *handicap* in the system (next to me the driver/tuner lol :lol: )

RICE RACING
12-02-2010, 12:16 PM
Some good info here, so long ago too!

I will post up some info from my new car here if people still read this????

Howerton Engineering
13-02-2010, 03:30 AM
Please post it up. Many people use the forum for help and information. The more knowledge the better.

ziad
13-02-2010, 06:04 AM
yes agreed. i have been thinking of just running water when i take my car on track (when i do). as with meth/water it will be too much power for the engine and tcase/gearbox. so i want to run WI for its knock supression quality.

obviosuly i understand that results might be different usign different cars.

Tom_UK
17-10-2010, 06:58 PM
Yes, please post more! It's great to see such detailed data on the net form someone who obviously works from first principles!

RICE RACING
08-11-2010, 01:00 AM
I posted alot of detailed information in my own road car thread showing application of water inection on a 13B-REW (rotary engine). It's in the members rides section for those interested.

EVILLUSION
02-10-2011, 06:43 AM
thread revival time, I have a LC-1 WB in my Evo and had it tuned to 11.2 on PULP anyway I proceeded to tune it to 11.5 with water/meth but had alot of trouble trying to introduce any timing to it as it would knock.
At a recent dyno day, my WB read 11.5 as i had tuned it to, but the dyno one read 13.8 and the car was down on power.
I put my non-water/meth fuel map back in, which was approx 8% more fuel on the fuel tables tested it no water/meth and it read 11.8ish (hot day autronic ecu charge temps etc) turned on the water/meth and the WB read 11.5 again, I added 2 deg timing and picked up 50kw on vdr.
Is it normal for the WB to be affected but the water/meth, what can be done to compensate for it.