Vp ms109

Riptide

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I ran 5g of MS109 through the car on a 91 pump tune. Several WOT pulls and some normal driving.

I am reading this may have caused the car to run lean due to the lower stoich of the VP fuel.

Question. If the car was leaning out then why was no knock recorded in the WOT logs? Timing even advanced by 3 deg. What am I missing here?



http://www.svtperformance.com/forum...-Has-anyone-had-any-issues-running-MS109-Fuel
 

corepwn

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Ms109 is more tolerant and less likely to knock even at a lean mix on a 91 tune than 91. That's why you could run it on the same tune where it was lean but you saw full timing your tuner allows on 91.


People have run boosted ms109 cars at proper airfuel to 23 degrees and more of timing. I bet your 91 tune peaks at 19 or less when running ms109.
 
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Riptide

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Thank you. I guess this ms109 really is good stuff then. Better be for 77$/5g lol

Henceforth I will run it only when I have a tune loaded for it. Back on pump soon. Maybe I ought to reset the ECU before I do that.
 

wile2k

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What were your short term fuel trims when you were running it

Aaron, good to see you on this post. This has me wondering if I have a fundamental flaw in my understanding of this.

In the above mentioned thread, both Eric@JPC and Beefcake (both of whose knowledge I respect) seem to indicate that running MP109 on a E10 tune will cause you to run leaner than expected at WOT. I don't see how. E10 is going to be stoich of ~14.1:1 while MP109 is ~13.4:1, and let's say we are commanding a .788 lambda in the tune... For the E10 that is going to be an AFR of 11.1 and for MP109 it is going to be 10.56 (thus slightly richer than what would have been expected and seemingly very safe).

I'm more concerned in the other direction, for example in my tune lambda is set to 14.08 (expecting E10) and .788 at WOT is 11.1... If I run non-Ethanol gas (14.7:1 stoich), then that same .788 is now an uncomfortable AFR of 11.6 which I think is too lean for a boosted car on 91 (even given my conservative timing of 14.5 degrees).

Anyway, Riptide, I just don't see the concern with MP109 on your E10 tune. On top of MP109s crazy octane rating, it seems to me that you are actually running slightly richer than your tuner commanded due to the change in stoich. You probably aren't getting your money's worth without tuning for all of the octane but from a safety standpoint, I just can't see a problem.

I can see a problem if you were tuned for MP109 and ran E10 (not even talking timing, just stoich). If you were tuned for 11.0:1 on MP109's stoich of 13.4 (.821 lambda), then ran E10, your AFR would be 11.56 (14.08*.821) which would then be leaner than expected, and perhaps too lean... Heaven forbid if you ran non-ethanol on that tune (14.7*.821 = 12.07 AFR, much leaner than you'd like for a boosted application).

Aaron, I hope you pop back in to correct my understanding if I'm off...
 

corepwn

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You have a fundemental misunderstanding of how lambda works.

14.1 stoich x 0.78 lambda = 10.99AFR
13.4 stoich x 0.78 lambda = 10.45AFR

When the computer is tuned for a e10 stoich (14.1~) the computer is going to use the WB02s to target the commanded lambda for the set stoich. In this example, that's 10.99AFR. The problem is that the stoich for MS109 is different, and requires even more fuel to hit it's lambda of 0.78 which would be a 10.45 AFR.

So in Rip's tune the lambda has remained the same in the tune but the stoich is wrong, which causes him to run a 10.99 AFR where the fuel should really be at 10.45AFR, hence the lean condition.

The only thing that needs to change in the tune is the stoich value (and timing), lambda tuning is great.
 

Aaron@JPCRacing

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Alright so here's the deal.

MS109 requires roughly 6% more fuel then E10.

So if you had a car that didn't have wideband correction (open loop) your car would run 6% leaner then it would on E10. That means if on E10 your car was 11.4 @ WOT it would be about 12.08 AFR on MS109.

I think the part your mixing up is that MS109's Stoich of 13.4 is actually 1.0 lambda on MS109.
Just like on E10 14.2 is 1.0 Lambda
E85 stoich is 9.72 and is 1.0 Lambda
 

wile2k

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Every time I think I have it, I lose it :). Thanks for taking the time to reply and help me get it clear in my head.

I'll have to sit down and play with the math to get it right again (poor brain must be getting old). Both responses should help me get there and thanks again.
 

wile2k

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Alright so here's the deal.

...
I think the part your mixing up is that MS109's Stoich of 13.4 is actually 1.0 lambda on MS109.
Just like on E10 14.2 is 1.0 Lambda
E85 stoich is 9.72 and is 1.0 Lambda

I do understand the idea of Lambda, I'm just mixing something up in my head on the way the ECU calculates it, specifically I think it is just related to where we set stoich in the tune, and how it calculates off of that number (and how that relates to using a different fuel with a different stoich). Thanks for the pointers Aaron!
 

Rct851

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So mixing a few gallons of this stuff to a 93oct tune is dangerous and has no benefit without the tune being specific for it?
 

wile2k

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So mixing a few gallons of this stuff to a 93oct tune is dangerous and has no benefit without the tune being specific for it?

It can boost octane (for some safety when you are beating on it, say a track day) and help rule out false knock. All anyone is saying is that it alters the Air Fuel Ratio a bit (based on how much you mix in). Other high octane fuels are closer in stoichiometric to regular gas and will have less effect on AFR. I'd talk to your tuner about it to see if they have any concern but I personally don't think it would hurt anything for the limited purposes I've listed.

I will say that you won't get much HP benefit from it without being tuned for it (unless you are knocking and the ECU is retarding timing badly).
 

wile2k

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So back to the post Rip referenced in the OP.

I'm still at a loss on where this would cause a problem on our cars (why would a tank of MS109 "make it run lean")? We tune for lambda, the WBO2 sees lambda, and we command lambda in the tune, right?

Back to Riptide's example... If his tuner is commanding .78 lambda on his E10 tune he will be running 10.99 AFR on E10. Say he then puts in a full tank of MS109 it is still going to command .78 lambda which now equates to 10.452 AFR. Even if he throws in a full tank of E85, it is going to command .78 lambda on that, so now running about 7.68 AFR (assuming his fuel system can keep up). All of those are close to the AFR required for those fuels (maybe not perfectly optimal but also not dangerous). I can see a problem on older technology where we would set fueling statically, but with the Coyote, WBO2 sensors, and closed loop fueling, why would this cause him to be "lean"?

One area that I need clarification on is why do we have a parameter to set a reference stoichiometric in the tune (in my case set to 14.08)? The only reason I can see for that is if the ECU was to output (or use) a calculated AFR it would need to know the fuel stoich to calculate off of based on WBO2 lambda reading. What am I missing there? Maybe this is where I go astray but I'm just can't put my finger on it.

Thanks for the interesting discussion.
 

Riptide

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What were your short term fuel trims when you were running it
My log files are unfortunately unavailable at the moment on another PC.

To make a sorta long story short as possible.

I had a base 91 tune for my tvs and had a lot of knock activity. To rule out gasoline as the cause I bought the 5g of MS109 and put it in and tested again. No knock and ECU advanced timing 3 degrees. Thusly proving the knock had been caused by the poor quality 91 I put in the car and not false knock.

That was the whole point of running it. The tuner told me to remind him that it was in there since the trims would be off.

I am almost done with the MS109 in the car and am going to reset the ECU and load some 91 from another station and try again. Incidentally I bought 25g of MS109 today because I eventually want to get a tune for it and run it mainly at the race track. From now on I will not run it with the pump fuel tune.
 
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corepwn

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So back to the post Rip referenced in the OP.

I'm still at a loss on where this would cause a problem on our cars (why would a tank of MS109 "make it run lean")? We tune for lambda, the WBO2 sees lambda, and we command lambda in the tune, right?

Back to Riptide's example... If his tuner is commanding .78 lambda on his E10 tune he will be running 10.99 AFR on E10. Say he then puts in a full tank of MS109 it is still going to command .78 lambda which now equates to 10.452 AFR. Even if he throws in a full tank of E85, it is going to command .78 lambda on that, so now running about 7.68 AFR (assuming his fuel system can keep up). All of those are close to the AFR required for those fuels (maybe not perfectly optimal but also not dangerous). I can see a problem on older technology where we would set fueling statically, but with the Coyote, WBO2 sensors, and closed loop fueling, why would this cause him to be "lean"?

One area that I need clarification on is why do we have a parameter to set a reference stoichiometric in the tune (in my case set to 14.08)? The only reason I can see for that is if the ECU was to output (or use) a calculated AFR it would need to know the fuel stoich to calculate off of based on WBO2 lambda reading. What am I missing there? Maybe this is where I go astray but I'm just can't put my finger on it.

Thanks for the interesting discussion.


1.00 lambda is the stoich of whatever fuel you're using.
If you input a stoich of 14.08 for e10 then the WB02s will look for the 10.99afr or 0.78 of 1.00 which in this case is 14.08.

The properties of the fuel define its stoich.

If you tell the ecu that stoich is 14.08 it will add just for 0.78 of that regardless of fuel used.

And 10.99 afr on a fuel that requires 10.4 to be 0.78 is lean.

You can't tune by lambda decimals if you don't define lambda 1.00 (stoich)
 

corepwn

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For extra clarification you must define the stoich for each fuel, but you can keep the same decimal when commanding fueling.
(0.78)

14.7 gas stoich
14.08 e10 stoich
13.41 ms109 stoich
9.85 e85 stoich

You can see here why e85 needs a bigger fuel system to keep up, it's stoich is about 40% lower so that much extra fuel is required.
 

wile2k

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...

You can't tune by lambda decimals if you don't define lambda 1.00 (stoich)

This is the part that I'm not understanding. What part of the tune cares about the stoich value (I know where I input it but where / when does it actually use it)? I don't think that the WB02 cares (reads natively in lambda), and the commanded afr is represented in lambda, where in the ECU is it actually making use of a calculated afr?
 

wile2k

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...
If you input a stoich of 14.08 for e10 then the WB02s will look for the 10.99afr or 0.78 of 1.00 which in this case is 14.08. ...

This is where I get lost, from what I understand, the WBO2 doesn't "look for" an afr, it simply sees a lambda value... Do I have that wrong?
 

twistedneck

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Some more stoich's and different fuels.

Pure Gasoline 14.7:1 - very hard to find and not good for new turbo cars
E10 14.1:1 - typical premium
E70 10.7:1 - winter E85 in northern states
E85 9.8:1 - std. E85 during summer
E98 9.1:1 - my favorite fuel
Methanol 6.4:1
Nitromethane 1.7:1

See a trend? the faster cars show up lower on this list. Why? because the lower you go on the list the more oxygen the fuel carries inside of it, the harder it is to ignite, and the more compressible the fuel becomes. Gasoline does not contain oxygen but many exotic gasoline fuels like FTW are oxygenated in the lab so they cheat.

A dragster can run so much fuel that it actually fills the combustion chamber completely. This would normally destroy the engine and bend the rod and fracture the piston and block. However, since there is so much oxygen and compressibility in the Nitro it does not crack the block, it can easily burn with just its internal oxygen supply, and it will not pre-detonate since its very hard to light in the first place, give me two spark plugs please!

so back to the OP, yea you ran lean but the car will account for that adding fuel as needed to make sure measured lambda in the exhaust is 0.83 or what ever your setting was, as long as your fuel trims did not show adding more than 15% (1.15) you wont even see an engine light. Other way around every time you put in 100% gasoline from some mom and pop station you are then too rich and the car must take away fuel.

Go E85 man! the built in cleaning of internal parts like valves, ports, and combustion chambers alone is worth it.
 
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