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QWKSNKE
04-12-2009, 07:43 PM
Great info from Eric Brooks on modularfords


Ever wonder if your airfuel will change with race gas? The answer is yes....

Real gasoline has various different stoich points due to the blend, how much ethanol is in it, etc. It is somewhere between 14.1 and 14.7 though.

Finding the information on race gas isn't easy. It is not posted anywhere on the internet that I have found. VP does not publish it, nor does Sunoco (TurboBlue)

Several weeks ago I got in touch with the chemist at VP and got all the stoich points of their fuels. Last week I got in touch with a Sunoco chemist and got the data from him as well.

When I asked the guy from Sunoco why they don't publish the information on the TurboBlue website he said -

Quote:
Eric - you're right, stoichiometry is important. Fact is many people have no idea what it is - kudos to you for knowing. Unfortunately many folks we talk to think the stoichiometric air/fuel ratio is where they should set their fuel system at wide open throttle. So we are torn about posting or not posting stoichiometry data because of that potential problem.
Shocking right? Especially when you see how different the fuels are...

Here is a list of the ones I have gathered.

Sunoco MO2X UL – 14.5
Sunoco 260 GTX – 14.4
Sunoco 260 GT – 13.9
Sunoco 260 GT Plus – 13.7
Sunoco Standard – 14.8
Sunoco Supreme – 14.9
Sunoco MO2X – 14.5
Sunoco HCR Plus – 14.8
Sunoco Maximal – 15.0
Sunoco MaxNOS – 14.9


Turbo Blue Unleaded (100 octane): 13.9:1
Turbo Blue Unleaded Plus (104 octane): 13.7:1
Turbo Blue 110: 14.7:1
Turbo Blue Advantage: 14.9:1
Turbo Blue Extreme: 15.0:1


VP Street Blaze 100 = 14.16
VP C10 = 14.53
VP 110 = 15.09
VP C16 = 14.77
VP MS109 = 13.41

Back to pump gas.... While I had the Sunoco guy's ear, I tried to get an answer about the stoich of their fuel and to find out how much actual Ethanol is in it, when the label says up to 10%...

Here are his comments...

Quote:
I know plenty about pump gas, enough to say that there is no useful stoichiometry data on pump gas. Composition varies WAY too much, regardless of brand/refinery/etc... especially on the lower octane grades.

But I can tell you that Sunoco 94, which is very hard to find these days, will contain some ethanol. Per the first sentence, it will depend on the blend though. I would go out on a limb and say it is nearly 10% most of the time (keep in mind 10% is the max allowed by law).

Street gas blends change all the time thanks to environmental requirements (fed/state/local), seasonal adjustments, and price pressures.

SlowJoe
04-12-2009, 08:06 PM
so me running VP110 it needs to be 15.09?????:think:

QWKSNKE
04-12-2009, 09:52 PM
.....EDITED this post.......

another quote
Some of the race gas like C16 has a similiar stoich point, so there is little change.

If the stoich is numerically lower than pump gas, it will run leaner.


EDIT.. Here is the original thread Joe http://www.modularfords.com/forums/showthread.php?t=132632
EDITED again...disregard original post I was wrong in my thinking.

waypastcrazy
04-13-2009, 07:20 PM
so me running VP110 it needs to be 15.09?????:think:a few variables come into play here alot depends on the blue print of the engine such as is block sqaured decked is is engine set up for quench aluminum vs cast heads are all the chambers cc'd the exact, are all injectors performing exact same,valve adjustments, ring gaps,are intake runners flowing exact same etc etc. one misconception is sometimes or alot of the time when afr is set at the perfect stoich the engine will mis or vibrate and people think it is detonation when in reality it is opposite cylinders are making different amounts of power that is one of the reasons you will see tuners run to the rich side to smooth things out. as such was learned from airplane techs way back when.lol it takes alot of careful machining and planning to produce an engine that will run at or near perfect stoich. one key tool would be to have a sensor on each individual cylinder.lada da da da da! enough said for now.but it is good to know the stoich of each fuel as such to get as close as possible and still run smooth. but what do i know?jmo.lmao budlight time. brain needs a break.

SlowJoe
04-13-2009, 07:25 PM
a few variables come into play here alot depends on the blue print of the engine such as is block sqaured decked is is engine set up for quench aluminum vs cast heads are all the chambers cc'd the exact, are all injectors performing exact same,valve adjustments, ring gaps,are intake runners flowing exact same etc etc. one misconception is sometimes or alot of the time when afr is set at the perfect stoich the engine will mis or vibrate and people think it is detonation when in reality it is opposite cylinders are making different amounts of power that is one of the reasons you will see tuners run to the rich side to smooth things out. as such was learned from airplane techs way back when.lol it takes alot of careful machining and planning to produce an engine that will run at or near perfect stoich. one key tool would be to have a sensor on each individual cylinder.lada da da da da! enough said for now.but it is good to know the stoich of each fuel as such to get as close as possible and still run smooth. but what do i know?jmo.lmao budlight time. brain needs a break.

so i could lean on mine a little more with vp110

waypastcrazy
04-13-2009, 07:27 PM
so i could lean on mine a little more with vp110yes you can

QWKSNKE
04-13-2009, 08:15 PM
one key tool would be to have a sensor on each individual cylinder.....

l would think this would be very beneficial when tuning a carb motor, right?

waypastcrazy
04-13-2009, 08:50 PM
l would think this would be very beneficial when tuning a carb motor, right?it depends on how much a person knows about setting up a carb for tuning and how well balanced the intake runners are but yes it definitely will show just how much a copy cat knock off intake or out of the box carb is way off on afr from cylinder to cylinder.very few people take the time to study and learn how to tune a carb i have met 0 that have.fuel injection is far easier but myself i enjoy the learning process of both.if i get into carbs we will be here for a while lol iab,mab,tc,iam,etc,etc:boxer:

waypastcrazy
04-13-2009, 08:53 PM
:chug:

SlowJoe
04-13-2009, 08:56 PM
something i will start on sat!!! another learning curve.:banghead:

QWKSNKE
04-13-2009, 09:43 PM
.....and how well balanced the intake runners are but yes it definitely will show just how much a copy cat knock off intake or out of the box carb is way off on afr from cylinder to cylinder....

That is exactly why I asked that question. Seems to me it would be hard to 'tune' a carb car without measuring AFR or exhaust temps on each cylinder. Based off the carb intakes I have been around it seems like it would be real easy to either have the cyls 1,4,5,& 8 to lean or to fat when trying to balance out your power per cylinder.

Is it safe for me to assume that on your standard single carb setup that cylinder a/f mixture will never be balanced because of the typical intake design?

waypastcrazy
04-13-2009, 10:05 PM
That is exactly why I asked that question. Seems to me it would be hard to 'tune' a carb car without measuring AFR or exhaust temps on each cylinder. Based off the carb intakes I have been around it seems like it would be real easy to either have the cyls 1,4,5,& 8 to lean or to fat when trying to balance out your power per cylinder.

Is it safe for me to assume that on your standard single carb setup that cylinder a/f mixture will never be balanced because of the typical intake design?yes i agree.that is why it is important to blue print everything else. if you dont then the cylinders that are off would be magnified even more so.most power would be made by taking the leanest cylinder and getting it as close to stoich as possible this would give the smoothest operating hp.details details makes it fun to play.i beleive that the taller the plenum the more consistent a carb setup is.just wish i had the dough to efi my little motor.guess i will have to settle for one tall arse intake.lol makes for good chat though.ps i do know of 2 porters that get the runners within a few cfm though.$$$$$$$$$$$

waypastcrazy
04-13-2009, 10:08 PM
What would be nice is if i really knew what i was talking about then i would be dangerous!

SlowJoe
04-13-2009, 10:12 PM
so it would be a good ideal to have my injectors flowed?

waypastcrazy
04-13-2009, 10:15 PM
so it would be a good ideal to have my injectors flowed?from my understanding the obdII is adjustable from cylinder to cylinder maybe someone with more experience will chime in.

QWKSNKE
04-13-2009, 10:34 PM
so it would be a good ideal to have my injectors flowed?

Are we talking on your mod motor? I would say no. Ford injectors are usually close enough from what I have read. You would have to have a pretty radical combination to worry about going that far

waypastcrazy
04-13-2009, 10:38 PM
That is exactly why I asked that question. Seems to me it would be hard to 'tune' a carb car without measuring AFR or exhaust temps on each cylinder. Based off the carb intakes I have been around it seems like it would be real easy to either have the cyls 1,4,5,& 8 to lean or to fat when trying to balance out your power per cylinder.

Is it safe for me to assume that on your standard single carb setup that cylinder a/f mixture will never be balanced because of the typical intake design?lol my setup will not be typical carb setup up intake will be balanced.heres a question to show how old you are how would you change timing to off set it from cylinder to cylinder on a good old plain duraspark setup?

Dale McPeters
04-14-2009, 07:27 AM
I do not see anything on pure old hillbilly grain alcohol......:D

QWKSNKE
04-14-2009, 07:58 AM
lol my setup will not be typical carb setup up intake will be balanced.heres a question to show how old you are how would you change timing to off set it from cylinder to cylinder on a good old plain duraspark setup?

Sorry I didn't mean YOUR setup. I was using the word as a generalization. I guess I should have just left it out.

To answer your question, I have no idea. I have never had the desire to build a carb motor for the strip. Hell, I haven't owned a carb motor since 1995.

waypastcrazy
04-14-2009, 11:07 AM
I did not take offense I just having good ol hotrod chat. The answer is the tangs on the stator can be shaved or even some older guys have bent them slightly. Kinda one of those things like placing pipe cleaner in the pushrods to slow oil flow down to the rockers back when the pipe cleaners were made of real material not the cheap stuff today. Lol I just having fun. Got an oversize load today so back to work I go.

waypastcrazy
04-14-2009, 11:15 AM
On the upside I am just starting to learn efi the spanish oak processer is really making it the way to go.I like doing things the easy way if it works and modern day efi really does. So keep on posting any new info because I really do pay attention to all that is posted. Thx clyde

SlowJoe
04-14-2009, 11:27 AM
On the upside I am just starting to learn efi the spanish oak processer is really making it the way to go.I like doing things the easy way if it works and modern day efi really does. So keep on posting any new info because I really do pay attention to all that is posted. Thx clyde

+1 i do like to tune on fuel that i know is the same everytime.

QWKSNKE
04-14-2009, 12:02 PM
On the upside I am just starting to learn efi the spanish oak processer is really making it the way to go.I like doing things the easy way if it works and modern day efi really does. So keep on posting any new info because I really do pay attention to all that is posted. Thx clyde

I agree. The Spanish Oak seems to have a lot of opportunities to be dug around in.

waypastcrazy
04-14-2009, 04:11 PM
You should clean up my mess here and make the fuel stoichs a sticky it is good info.

waypastcrazy
04-14-2009, 04:20 PM
There was this guy that used a carbed intake and fuel injected it and went lean on the 4 center cylinders.right the opposite of a carbed setup. His set up was 4 inj on each bank so he was limited on adjustments. His fix was he put the 4 center 2. 3 and 6 and 7 cylinders on 1 bank and 1 4 5 8 on the other kinda like 2 v4 engines. That was pretty cool.