Meth inj tuning questions..chime in Scott, Doug, slowwrx

I'm trying to squash a bug here for arguements sakes. Several people have told me that my tuner is an idiot and I'm getting tired of saying "Well it must take an idiot to be the tuner of the 1/4 Mile EJ205 record holder."

The question that prompts the arguement over and over. Why does SS tune meth injection to 10.4 AFR. I'm not entirely sure but I think it's because Scott is using way more timing and the richer AFR keeps things nice and safe. I know at my 22.5 psi I'm making 368 tq and 358 hp whereas others with my setup are hitting almost the same numbers but at 24-25 psi and 11:1 AFR.

So what is the answer here so I don't look like an idiot? Does Doug tune meth injection the same way? I'm not trying to start things here but looking to understand how the car and the tune works together so I can explain it to others.

Matt is your One Lap car tuned to the same AFR or did you and your HUGE BALLS get Scott to push the car a little leaner?

 

I dunno but am getting tuned again Friday (had some minor changes) but I have the same meth kit as yours. If SS does not answer before then I will have him post up. Thanks for raising this as I am curiuos myself, but am still learning.

 

I want to stress that I am VERY happy with my tune from SS and I have absolutely NO complaints. Just looking for techincal answers to explain and back up what I tell others.

 

Well the methanol is less likely to spontaneously detonate when compared to regular fuel so that might allow for a leaner tune than stoich while maintaining reliability.

 

Leaner is all relative to how much timing is in the car, Scott likes to run the car richer and run more timing, its safer that way for sure. Thats the way we ran the one lap car and I'm willing to bet there isn't another subaru in the country that has 10,000 "Matt" Track miles on it. Not making the same power anyway.

 

Stoich for meth is in the 6 to 1 afr range...

SS

 

You only lean the AFR out with between 100% water and about 70% water, 30% meth. With pure meth you run MUCH richer.

Stoich on gasoline = 1 Lambda = 14.65:1 AFR
Peak power on gasoline "near" 11:1 AFR = 0.75 Lambda
Stoich on methanol = 1 lambda = 6.47:1 (yes six and half)
Peak power on methanol = 0.8 lambda = 5.2:1 AFR (yes, vehicles that run straight methanol run in the FIVE to ONE Air to Fuel Ratio at WOT)
So adding 100% methanol to gasoline = moving from 11:1 AFR toward 5.2:1 AFR = getting richer.

With more than 30% water, the water is absorbing so much energy that you have to lean it out to make power... with more/straight meth, you actually run richer than you did on pump gasoline.

 

Thanks for the explanation Scott. I'll proceed to squash this bug with my new info.

 

My 2 cents,

FWIW, widebands typically measure equivelency ratio, then use that to calculate lambda. AFR is then estimated by multiplying lambda by a fixed fuel multiplier (typically 14.7). So, if you are using AFR for tuning, you are already really using lambda, just multiplied by a fixed amount.

I actual find lambda a lot more intuitive than the psuedo AFR from a wideband. For me, mentally tuning to, say .78 lambda makes sense - I'm looking for the same mixture relative to stoich for the same relative efficiency. In addition, if you are using meth you will still tune to the same AFR (gauge reading) that you use for gasoline alone because your wideband is still using the same fixed fuel multiplier. This causes tons of confusion among most tuners.

From this chart you can see that even though meth has a stoich of 6.4 and gasoline has a stoich of 14.7 they both have the same lambda reading of 1.00.

To make a long story short, you shouldn't tune on meth any more rich than you would on 106oct race fuel. Usually I tune mid to low 11's on meth and pumpgas.

 

Hmm so we have two different philosophy's going on here.

I'm so confused.

 

This thread deserves a sticky

 

Yay I created a stickable thread! LOL

 

We don't really have different theories. The LM-1 that I use reads 0.6 to 1.0 richer than almost anything else. So the 10.4 on the LM-1 is more like 11.0-11.4.

AFR is *NOT* Lambda. If you have a wideband set to Lambda on the dash, next to one set at AFR and you are running a STRAIGHT meth car at cruise. The Lambda says 1.0 and the AFR says 6.45. On Gas the lambda says 1.0 and the AFR says 14.7...

Most of my meth cars that are set to run 10.2-10.4 on an LM-1 will ping at 10.6...

I would imagine that on the same wideband Doug and I's pump gas and pump+meth cars run very similar afr's...

Siegel
Siegel

 

See this is why we pay you the big money,

~over~
myhead


Though I'm enjoying learning

 

Like I said Scott you are a genius....lol

Scott are you still using your LM-1 or are you using the DynoJet's wideband now?

Now EVERYTHING makes sense to me. When tuning your car and monitoring it, AFR is NOT really the way to do it. Lambda is the way to do it....right?

 

AFR seems to have worked so far

 

Well when you 'KNOW' what to look for! Haha

The thing is EVERYONE on Nasioc is slamming you Scott because we (we being the passenger in the seat while you tune) are seeing 10.4 on the LM-1 so we say my car is tuned to 10.4:1 AFR. THen the tards on Nasticock say you are running WAAAYYYY TOO RICH.

That's where the confusion comes in but in reality you are tuning off of Lambda behind the scenes right?

 

same here bro!hnoes:

 

LOL. I think one of the main things is that wideband's are different. Running the LM-1 at the same time as the $3000 Motec wideband on the Dynapack, the curves are always the same shape, but the LM-1 is 0.5 to 0.8 afr richer.... So you're 10.4 on the LM-1 is 10.9-11.2 on the Motec.

What really matters is that when it leans out over where I set it, it pings. When it stays where it's set it goes FAST

Siegel

 

Yep Scott is 100% right. Like stated above 'I think but don't wanna reread' the AFR is pointless somewhat. When Doug or Scott tunes they are actually tuning against lambda. They may use AFR but in reality they know that xx.xx AFR = 1 lambda. Lambda is always consistant but the the algorithm to get AFR may be different hence the different AFR readings. As long as your tuner knows what 1 lambda is (Scotts is typically 10.4 if he uses his LM-1 and Doug's dyno wideband is 11 I think) then you are all good!

Every wideband is calibrated differently when it comes to AFR.

Tuners correct me if I'm wrong.

 

man ss and doug really got it going on

 

Yes they do....they are the best!

 

So the question is, which one is CORRECT?

 

^^^

So what would the answer be?

 

My TurboXS wideband reads about .2 higher than what the Innovate would.

 

This thread is awesome. I don't think I will ever put Meth on a car, but the technical background is always good to know. Thanks for the info!

Anyone doesn't get some of the AFR/Stoichiometric techno-babel, buy this book or borrow it from me. It is amazing. That is all.

 

http://www.fordmuscle.com/archives/2007/06/WidebandShootout/index.php

I remember seeing the entire article somewhere w/out needing a subscription....but I cant find it now.

 

That's your loss.....you are missing out on a LOT! Doug and Scott would both agree.

Race gas works better but comes at the expense of costing 2-3x more.

 

Ha ha, I just switched from a mild B18 in an Integra to the 2.0L with a VF39. Call me crazy but ~320 hp is plenty for me. If I was going for big power it may be a different story...

 

Not to mention that it is NOT readily available at every fuel station.

 

How in the world are you getting 320hp on a VF39 on a 2.0L? At the crank yeah but wheel....doubt it.

 

I was talking about crank. This has a SS road tune (when he was at SOG) and I have never dynoed it, so I have no idea what the whp is.

 

while the information in this thread is outstanding, i think the real problem lies in visiting nabisco, eating their trip-inducing cookies and coming back here right about the time you peak.

 

I was just relaying to Scott that the idiots that don't have a clue how to tune are bashing him and therefore trying to hurt his rep by saying he can't tune because he tunes too rich. In reality it's not too rich but spot on.

 

i know... i was just fuckin with ya

 

i am new to all of this, i would just like to ask what kind of meth kit you guys are running. i have an 02 wrx with vf39 turbo sti pinks turbo back and i dont know what kit to get and i also know that everyone has there on idea of what they like i just dont want to buy a POS kit.

 

get the SMC meth kit, they have fixed the pump problems or at least my most recent one has had no issues. Customer support is top notch.
It will make for a killer setup I had that same setup before going to a DB18G.

 

SMC here.....if anyone was busting the pumps it was me and I was one of the major beta testers for all the pumps. Last one has been FLAWLESS since Steve @ SMC got the thicker seals made.

 

This is a very interesting read for sure. Definitely some different logic going on with the use of methonol in my experiences.

Something that we do with big blown V8s is to run your standard 11.2 to 11.8 A/F since methanol/water injection is an additive. We will usually run about 2-3* more timing an/or 3-4 more pounds of boost.

 

you just bumped a 3 year old thread

 

You're right, but its also a sticky. No reason new info or questions couldn't be added.

 

not a sticky, but you're right interesting stuff for sure

 

I'm going to be putting meth/water on my lightning first, and depending on the results, put one on the STi and WRX as well.

I was going to move to E85, but its not readily available around here.

 

I've said this before but its worth repeating. Call around to all the shops and ask how many of the owners\employees are running meth injection on their Subarus.

The answer is almost none.

Its not worth the risk.

 

What risks do you speak of?

 

I would like to know this as well.

Ball - Would you prefer meth or E85 and why?

 

buy a real pump

 

But aren't you guys running the typical 50/50 mix?