Alky and how it affects o2 numbers

[d0n_3d]

When you are spraying straight 100% denatured alcohol...how does it exactly affect the o2 numbers on the top end? I noticed when I run my car, the o2s start in the 830's and then drop according to rpm and mph and right around the 110 mph mark which is nearly 5000 rpms, the o2s are at 765. I thought the alcohol added fuel thus raising the o2s a little higher on the top end? I've been told the alky will also throw off the o2s at WOT because it is an oxygenated fuel unlike gasoline. I'm running about 24-25 lbs of boost right now with straight 93 pump gas and the dual nozzle SMC kit is at pump speed 6 right now with no knock the entire run. I can probably still go down the pump speed but if the 02s are in the 760's then maybe I shouldn't? I'm just confused a little. Thanks.

 

[4sfed4]

Originally posted by d0n_3d
I've been told the alky will also throw off the o2s at WOT because it is an oxygenated fuel unlike gasoline.

I am wondering the same thing Don!

I guess there is one way to find out......spray the heck out of the car with the alky and see what happens to O2 voltages.

I do know this.....

I buddy of mine had a supercharged car with the simple Spearco water injection system on it. While on the dyno, we played with the size of the nozzles (the kit came with three sizes). We were using straight isopropyl alcohol.

Well.....on the dyno wideband, with each size UP in nozzle, the reported A/F also went UP! In fact, the wideband showed his car running at almost 16:1 up top with the largest nozzle and we were practically flooding the car. There is no way his A/F was actually 16:1. And, theres even less way that the real A/F increased as we were adding alky.

My unscientific conclusion.....

The wideband was getting tricked by the oxygenated fuel (the isopropyl). The widebands, as I understand them, are generally calibrated for gasoline. When you throw a different fuel in there (or a mixed situation like gasoline with alky spray), the sensor can get confused. The oxygen from the alky has to go someplace and I guess it goes right out the exhaust (i.e. the stoichiometric balance is different) and the sensor reads that as a leaner condition.

I am not sure if a narrow band O2 would read things the same way? Hopefully, this question wont start a riot!

 

[bruce]

The stock O2 sensors are temp sensitive, change the EGT much and their output can go to dodo.

Get a WB if you want to actually know what your AFRs are doing.

Not to mention that EGTs peg at stoich., and unless you know which side of stoich your starting with, even EGTs can be misleading.

 

[TT/Ameasap]

Originally posted by d0n_3d
I'm running about 24-25 lbs of boost right now with straight 93 pump gas and the dual nozzle SMC kit is at pump speed 6 right now with no knock the entire run. I can probably still go down the pump speed but if the 02s are in the 760's then maybe I shouldn't? I'm just confused a little. Thanks.

Try pulling some fuel out(93 octane) and adding more alky. It seems you are on the wrong side of the board with its current tune.You are not taking advantage of the cooling effects. I bet you change your tune to more alky and less 93 and you will feel a power increase.I have already been there.

just some advise

Bo

 

[tim87tr]

Re: Re: Alky and how it affects o2 numbers

Originally posted by TT/Ameasap
Try pulling some fuel out(93 octane) and adding more alky. It seems you are on the wrong side of the board with its current tune.You are not taking advantage of the cooling effects. I bet you change your tune to more alky and less 93 and you will feel a power increase.I have already been there.

just some advise

Bo

Yes exactly. This is how I tune also with the Razor kit and straight Methanol. I run a low timing Turbotweak street chip, and at higher boost it would be lean due to the lower boost fuel curves for the street chip. This worked well for me running alky because I can run 42 to 44 lb fp and add the extra octane and fuel requirements in higher boost with the Methanol. This chip is around 16 ms Injector PW at WOT in 3rd.

 

[bruce]

IMO, if your going to start to reply heavily on Alky for more then just a moderate amount of cooling, then you want to make sure that your *tune* is safe enough that under the worse case scenario your Knock Retard Limit is high enough to still keep the motor out of detonation. If you're running that much alky, then you might want to consider some sort of audio/visual knock warning devise.

I forget which code it was, but when I increased the knock retard limit to like 25d, the code went to lunch.

 

[d0n_3d]

well I am running those new 65 lb (60's as some call it) with a bone stock motor...maybe the chip has too much fuel on the top end? but why would the o2's drop like that on the top end if it had too much fuel? unless it's the alky showing me those false numbers...

i am gonna go to the track very shortly and do a race tune with c16 and a race chip and see what happens...probably right...i might have too much fuel on the top end for the alky to really take effect...thats why my mph is so low for this combo...hell i went 112 mph on a stock turbo and injectors!

 

[tim87tr]

Don, based on your info, and if you are not running a progressive system, I suspect that you are too rich in lower rpm and gears, and then at that same pump output that remains constant, you go lean in 3rd. I tune rich with just the alcohol and then just lean it out from there if necessary, although running a little rich with the alcohol does not seem to affect the car as much as rich with pump gas. I use EGT and DS to moniter the car.

bruce, you're right on the kr alert. Might be a good idea because I watch my SM going down the track.

 

[d0n_3d]

my kit is a progressive setup...guess i just gotta keep playing around with it...my goal was 11.50's on the alky and 11.00's on a race tune

 

[TT/Ameasap]

Originally posted by bruce
IMO, if your going to start to reply heavily on Alky for more then just a moderate amount of cooling, then you want to make sure that your *tune* is safe enough that under the worse case scenario your Knock Retard Limit is high enough to still keep the motor out of detonation. If you're running that much alky, then you might want to consider some sort of audio/visual knock warning devise.

I forget which code it was, but when I increased the knock retard limit to like 25d, the code went to lunch.

Yes, I totally agree whith you, but the more alky you spray in the motor, the higher the octane.The higher the octane, the more detenation is surpressed.The cooling effect seems to be relavent on the other end of the spectrum allowing for more hp.

Bo

 

[Razor]

I dont have any information on how the SMC progressive works. So to offer you any tuning advice on what to do with it??? Would be inappropriate. And that is something you'll need to work on/figure out.

My kit replaces probably over 20-25% of my fueling. If I tune for like 780-800's with alky and dont run the kit, my O2's drop into the high 600's low 700's on fuel. IAT's go to the 170 range at 20 PSI. With the kit spraying, same injector DC, I run 780-790's and IAT's of 90's through the traps.

Your chip may also be suspect, I know you run one of Joe's chips and I dont know if he's got a handle on making a chip that takes advantage of a progressive style controller. Remember IF its a progressive it will give you a flat linear response curve through out your boost. So the chip needs a ton of fuel pulled out throughout the entire PE tables to compensate. Unlike the old style kits that "HIT" the motor at a certain PSI..then the chip guy meerly tuned that out.. kinda.

An alky chip will make your car lean out pretty bad without the kit spraying.

So your really fighting two battles. Less gas and more alky.. less timing and more boost.

Leave you with this, on my 11.2 pass, my 50lb injectors were at 79-81% DC at 43 base pressure running 760's through the traps.

HTH

PS.. you got pink injectors

 

[d0n_3d]

pink injectors eh? LOL

yes this is very true...well it seems the car is running really well right now...I just need to "fine" tune it...I mean come on...25 psi of boost on a 61 turbo with the new 65's and no knock at about half the pump speed is pretty good? it ran 11.99 on 23 psi...probably could have been alot lower if i had the boost higher...i'll just be happy with a consistant mid 11's 93 pump gas and alky combo full time on the street and low 11's high 10's on a full race tune

remember this is all on a bone stock motor absolutely no mods except stronger valve springs done to it, full weight with all options GN, running heavy stock wheels with slicks, no trans brake just going off foot brake, and tuning with a combo that hasn't existed before...i guess i am not doing too bad so far?!

 

[Razor]

Hey,

You really have to be secure in your manliness to run 65's.. hehe

On a serious note, remember there is no "pump speed" on a progressive. There is a ramp . And that ramp dictates how fast and how hard the controller sends voltage to drive the pump. So I would hope your running it in mid position as that gives you the ability to go up or down on the delivery rate of progression.

My knob too is at half way




Back to chrome injectors with pink highlights.. bling bling..

 

[d0n_3d]

actually Razor...the 65's that I have are not "pink" (I thought you meant they were pink as in brand NEW never tried before so they haven't been tuned before)...actually they are the new Mototron 65 lb high impedence injectors that we sell...they are the long black skinny injectors...

but anyways...I will continue my fine tuning process...I actually turned down the pump speed this morning to 5 instead of 6 and I still got no knock even at 106 mph when the o2s read 777.

 

[4sfed4]

If anyone is ineterested, I did a quick test with the methanol to see how it affected my O2s and EGTs.

WHOA....It reduces EGTs bigtime.

It acted a little differently on the O2s than maybe some other guys have seen?

Normally for a given boost/power level, on gasoline only (race gas), the EGTs would be around 1775 F if O2s were 0.86V. (My Dodge doesnt run the same O2 voltages that Buicks do as I understand this would be very rich for you guys. But, its quite lean on a Dodge. This EGT and O2 voltage was about 13:1 A/F on the dyno wideband.)

Now...with the methanol, and 93 pump gas, at the same boost level I saw a peak EGT of about 1575 F while O2 volts were about 0.92V.

So...the O2 volts came up about 0.06V and EGTs dropped 200 F. What has me thinking is this.....

The reduction of 200 F in EGT alone would bring the O2 volts up even if actual A/F ratio didnt change. (Thats just a property of O2 sensors. The hotter they are, the lower the voltage output for a given A/F ratio.)

But, there is no doubt the methanol is adding alot of extra fuel (DUH). In fact, I could easily turn the gain up on the PAC and get the car to misfire due to overfueling and yet the O2 voltages were nowhere near the level they would be if I overfueled the car with gasoline?

 

[4sfed4]

Also...as many have mentioned...there is no new news here....IAT temps drop huge amounts with the methanol.

I was cruising around and IATs were in the 120 F range. Going to WOT with the methanol spraying I watched the IATs plummet even faster than my stock sensor could read them. Under 20+ psi boost, they were into the 90's and looked like they were still going down when I let out.

 

[Razor]

So while spraying your O2's went up and the EGT's went down..

And the IAT's went down as well..

Surprise

Now pull fuel out and drop the O2's with the kit spraying aggressive... and get it down to .86.. And watch the power take off...

Thats how you start the replacement.. from there timing.. and keep an eye on the egt's. as the O2 and EGT will always correllate unless there is detonation. At which point the egts will climb.

So you can bring it to its knees.. thats a wonderful thing

 

[4sfed4]

Originally posted by Razor
So while spraying your O2's went up and the EGT's went down..

And the IAT's went down as well..

Surprise

Yeah...I figured that would happen! But, I was surprised the O2s werent a little higher considering how rich I was running it and how cool the exhaust gas was. But hey.....who cares. The car seemed to be running fine

I will however put this issue to bed when iI hit the dyno in a few weeks. I am going to vigorously log O2s, EGTs and the wideband A/F and see how all of these relate to power. Once I find the "sweet spot" for the car, Ill know what to shoot for from then on.

Now pull fuel out and drop the O2's with the kit spraying aggressive... and get it down to .86.. And watch the power take off...

Thats how you start the replacement.. from there timing.. and keep an eye on the egt's. as the O2 and EGT will always correllate unless there is detonation. At which point the egts will climb.

So you can bring it to its knees.. thats a wonderful thing

I will try to get O2s down a bit and see what happens.

Question......

If I change the initial turn on psi on the PAC, will I then need to readjust the gain knob to get the same amount of spray under full boost? I currently have the turn on point the same as the PAC is shipped, which is about 4 psi or so I believe.

I ask this quesiton as when I turn the boost up a bit and set the gain so it gives perfect spray up top, it sprays a little too much down lower (in the 4000 rpm range).

Heres the other thing I found......surprised me big time.
When I overspray the car with methanol down low, the turbo spools faster! I noticed the car felt snappier down low after I added the methanol, but thought it was in my head. Then I datalogged it. Boost definitely ramped on faster. In fact, the boost came on in the same fashion with the methanol as it did when I spray a 15 shot of N2O!

Take a peek at this quick screen shot. The runs were started at slightly different rpms, so thats why one is much below the others right off the bat.

The dark blue line is boost with 93 octane gasoline and methanol spraying at 4 psi turn on point and the gain knob set at 12.5 oclock. The light blue line is is with 93 octane gasoline at 50m psi base fuel presusre and a 15 shot of N2O. The black line is on just 93 octane gasoline at a 50 psi base pressure.

The boost goals for these runs was obviously a little different as you can see where the curves level off You can also see the ignition misfiring on the dark blue curve as the boost line gets funky looking.

Any ideas why the turbo spools so much faster? No complaints of course

 

[Razor]

Ohh boy I found a tweaker

One thing that may happen is you spray too much alcohol and it burns in your exhuast. That heat may cuase your turbo to spool up faster. On our cars it was practice to spike the fuel tables at 2800 RPMs for such a purpose.

Now the turnon point i'd leave alone, but I understand you dont have control of your fueling so you may play with turning it on latter.

Now mind you the controller will ramp up exactly from whatever point your adjust its turnon point. To make the ramp more aggressive, increase the initial.. and vice versa. Remember the resolution discussion

The gain tweaks the initial control +-

 

[DR BOOST]

Originally posted by Razor
Back to chrome injectors with pink highlights.. bling bling..

i had to have bling bling injectors. fell in love with them when i saw em.

i also armor all my slicks.