Not sure exactly how popular. Way said that he installed only bout 45-50 and it is a rather long involved install. I haven't seen too many here on NAM. It seems that before my tune, I felt as I I had gained back a little of the torque I had lost with the exhaust. As it is supposed to be the JCW manifold, I don't see how it wouldn't help at least a bit nor how it would affect the warranty.

 

I've considered doing the manifold but decided I'm not going to touch it unless I'm swapping the turbo at the same time. It's just too much work IMO

 

I talked to the guys at RennTech and now I'm strongly considering going with their tune since their numbers are higher compared to NM, mind you I have an automatic. He told me I wouldn't have to worry about any power surge or issues on my transmission since they tend to help the way the transmission will react in lower RPM's.

I am going to talk to Jerry one more time before I make up my mind within the next month or two before I finalize my decision. $500 is a big difference compared to $945 or whatever RennTech is charging.

Maybe some people on here with the RennTech can tell me about their experience with their tune.

 

Idk man, just keep in mind that you're paying 445 bucks more for an extra 10hp and 2tq.

Maybe Jerry can give you those numbers if you ask?

 

Yeah I wish Renntech would lower their prices in line to be more competitive with what others are offering. $1000 is hard to swallow for a tune.

 

You should add meth injection and aftermarket seats to that list as well, just sayin

 

Yeah that's exactly what I plan on doing is getting a chance when I get back from San Fran and talk to him about what he could do.

 

Actually it might be even worse than that. I'm hearing that the +40 HP/40 tq for the RennTech tune is assuming 93 Octane and that for those of us with only 91 Octane gas, it's more like +25 HP/25 tq.

If that's true, a meth kit is probably a must have for anyone in California looking to get the RennTech tune.

 

I will talk to Jerry soon about it to figure out what tune better satisfies my needs cause in reality we all want more power but it needs to be realistic. Hopefully I don't have to go and pay $945 for a tune, I'd rather save the $445 for coilovers at that point.

Thank god we got 93 octane here in Michigan. Some Sunoco gas stations have 94 octane as well but for some odd reason my car loves Shell gas station since it acts awkward when I used to put in BP and Sunoco once in a while.

 

True here too... 93 octane.

 

The station here in town has a pump where all the crotch rockets fill up - 100 octane, $7.99/gallon. Ouch.

 

Fortunately/unfortunately, the decision has been made for me since NM cannot (yet) tune the post-Feb. 2012 ECUs. Unless something changes, it's RennTech or bust. Sucks, too, because NM is within easy driving distance for me.

93 Octane is but a distant dream for us in Cali. Le sigh.

 

It's 450 if you drive there instead of sending the ECU in...I was about to make the drive until I found out they can't do it after Feb.

So Renntech can forsure tune post Feb cars?

 

I will bring you some 93 octane when I come on March 20th to San Fran;-)

 

Yup. They can do it.

 

For those of you guys worried about the 91 vs. 93 octane premium, consider where you live and what the local and state emissions laws are as they pertain to ethanol content in gasoline.

I work in the petroleum industry. Around here in Chicagoland, all the Premium is 93 octane, but it also has 10% ethanol. Ethanol is used up to 10% in the state of Illinois (and other densely populated areas) for various emissions and political reasons. All of that aside, one of the side-effects of adding ethanol is a few points higher octane. This reforumulated fuel is called E10 (10% ethanol 90% gasoline).

Sometimes my job takes to me more rural places with low population densities. I'm not talking about smaller cities, I'm talking about Bu-fu middle-of-nowhere towns with populations less than a couple thousand. In these places, all grades of gasoline have 10% ethanol but the big stations (Shell, BP, etc.) always have at least one pump that has ethanol-free premium. The E10 premium is 93 octane, just as it is here in Chicago, but the ethanol-free premium is 91 octane.

I've driven my Mini to some of these places and ran full tanks of the ethanol-free 91 octane and the car simply runs better, it's a bit more responsive and gets about 10% better fuel mileage vs. running E10 93 octane fuels. (For reference, both of these fuels were Shell V-Power. The difference only being ethanol content.)

Straight Gasoline has a power rating of about 114,000 BTU per US Gallon.
E10 Gasoline has just under 112,000 BTU per US Gallon.

What's basically happening here is even though you have a higher octane rating with E10, you have less energy potential per gallon, and the stoichiometric ratio for E10 requires slightly more fuel than the stoich mix for Gasoline... You're burning more E10 per volume of air entering the engine than you would for 100% Gasonline.

The Bottom Line is...

ECU tunes that say they require 93 octane will often run just as well on 91 octane, assuming it is 100% Gas and not E10, because you will be using less fuel to make the same amount of power (by just less than 2%). Less total fuel takes less time to burn, which then, in turn, requires (slightly) less ignition timing. Such a small amount of difference that the ECU should/will/does easily adjust. Usually, you'll end up with almost zero noticeable horsepower difference, but you may notice a fuel mileage benefit as I did.

 

Interesting stuff, thanks for sharing. But what about the detonation resistance of the higher octane gas? I mean, it's not all about the energy potential of the fuel, right?

And how does methanol compare to ethanol in terms of its energy potential?

Also, I forgot to mention that in California, our gas is E10 91 octane. According to what you said: E10 91 < E10 93 < E0 91 < E0 93. If a tune is assuming EO 93, it wouldn't shock me that you'd lose a lot running the E10 91 we have here in California.

 

[QUOTE=TonyCheckraise;3689558]Sometimes my job takes to me more rural places with low population densities. I'm not talking about smaller cities, I'm talking about Bu-fu middle-of-nowhere towns with populations less than a couple thousand. In these places, all grades of gasoline have 10% ethanol but the big stations (Shell, BP, etc.) always have at least one pump that has ethanol-free premium. The E10 premium is 93 octane, just as it is here in Chicago, but the ethanol-free premium is 91 octane./QUOTE]

hey Tony,

up here in wisconsin, the E0 is 93 in the summer and 91 in the winter, though my 2012 cms all4 seems to run the same on either

i see 4-6 mpg less on E10, either 93 or 91

cold starts are much smoother on E0

scott

 

Methanol is generally not mixed into gasoline, but for reference

100% Methanol: 56,800 BTU/gal
100% Ethanol: 76,100 BTU/gal

So, if it were mixed with gasoline in a theoretical M10 blend (10% Meth 90% Gas)... It would be maybe 3-4% less powerful per gallon than E10. Not quite sure on the math. As far as detonation resistance is concerned...

Detonation (spark knock) is, for reference, when peak cylinder pressures during normal combustion happen before they are supposed to. This is caused ONLY by spark plugs firing too soon for the octane of fuel they are lighting off. This isn't to be confused with pre-ignition, which is when the air/fuel mixture ignites itself due to hot-spots in the combustion chamber or some other source of ignition lighting the flame before it is supposed to be. Pre ignition is usually caused by carbon hot-spotting, running a crazy lean mixture that heats up the CC, etc... That's a totally different issue. The higher the octane, the slower the fuel burns. We all know that, right? (Here it is, even if anyone didn't )

Detonation is eliminated by either running a higher octane fuel or by retarding spark timing.

If we were comparing E10 87 octane to E10 89 or E10 93, we would be talking about fuels that all have the same Stoichiometric ratio and BTU rating but have different knock resistances. We're comparing E10 to Straight Gasoline, they're two different fuels. Gas has more BTUs and a slightly lower octane but it also has a slightly leaner Stoich ratio.

Gas: 14.7:1
E10: 14.1:1

This means a properly burning mixture using a static volume of air (like your cylinder volume) will have less volume of Gas than an equally burning E10 mixture. Take something ridiculous like NHRA Top-Fuel drag racing for example...

The Mostly-Nitromethane (47,000 BTU) fuel that these engines run have about 40% the BTU of Gasoline (114,000 BTU) per gallon, but the stoich mixture is 1.7:1. Nitro also burns very very very slowly compared to Gasoline, so much so that a properly timed burn is still burning the entire exhaust stroke and 2-4 feet out the end of the exhaust pipe. (Hence the flames from Top-Fuel Dragsters... ) Anyway...

For every one Gallon of Gas you need 14.7 Gallons of air to release it's BTU.
For every one Gallon of Nitro, you only need 1.7 gallons of air to release it's BTU. But looking at it this way assumes you have unlimited air to support the burn and only have limited fuel. If you were pouring it on the street and lighting it on fire, this would make sense. But engines don't have unlimited air, they have a very specifically limited amount of air to use each time the engine rotates. So if we want to make power, we have to use to either add more air (Turbo), or use the air we have available to burn the best fuel for making power.

So let's reverse the constant... In two engines where displacement volumes are identical, you would be able to burn 8.6 times as much Nitro-fuel. For every gallon of air you could get into the engine, you would release;

Burning Gasoline: 7,755 BTU
Burning Nitrofuel: 27,647 BTU

All this does is show in an exaggerated fashion that the relationship between BTU and Stoich ratio is much more important than the burn rate/detonation resistance. Obviously, there are a lot of thermal efficiency and countless other physical variables that affect actual power output % vs. BTU generated. The idea remains the same. Back to the original issue.

The lesser volume of 100% Gas should take less time to burn than the volume of E10 required to make equal horsepower. This means the engine can run less spark advance relatively and still make the same amount of power because it takes less time from the ignition of the spark plug to peak cylinder pressure realization. The less advance there is in the spark timing, the closer the piston is to top dead center, and the less time there is for detonation to even have a chance to occur.

Bottom line... I'm not a tuner. I don't know what kind of fuel they're tuning for. So your best route is to always ask the tuner. BE SPECIFIC about what fuel you're going to be running. The only point I'm trying to make is that the differences between the two fuels are more complex than just knock resistance. I wanted to share my thoughts that you most likely shouldn't be worried about running 100% Gas 91-octane if you were tuned for E10 93-octane. Most likely the computer will adjust between the two without any problems at all. The only time I would worry is if you were tuned for E10 91 and then ran a lower octane E10 like 89 or 87.

 

Interesting you mention Wisconsin, as that's where I was referring to. Specifically, Wisconsin Rapids area (Vesper, where I go for work sometimes) and Merrimac (where my dad has a house near the water.) I've only seen E0 91, but I was only there with my MCS when it was winter, so I wasn't really paying attention in the summer when my sister drove us up in her Mitsubishi.

Where in WI are you?

 

Great info, Tony. I'll probably have to read it several more times before I start to understand it, though!

Regarding the bold part of your post, what if the tune is for E0 93 and I can only get E10 91? Is that enough of a gap that it would cause you concern?

 

That's something I would ask the tuner. If that's all you could get in your area, I would see if the person tuning the ECU could accommodate that.

IMO, I would think that 2 points of octane wouldn't be cause for much concern under normal driving conditions. Only under WOT/Full-Boost conditions is the fuel's octane really being put to the test. That's when you'll really know if you're fuel is up to snuff.

I had an incident about two months ago where I put about 10-gallons of (what I thought was) V-Power into my MCS. I immediately felt a loss of power. I didn't hear any detonation because the computer was cutting the timing and boost levels to adjust, but I knew it was 87. Regionally, Shell is one of my work's biggest clients and I deal with their regional environmental dude (John Robbins) directly. So I called him up on the phone and told him that it must have been a mistake on the fuel delivery person's part.

Short lesson for those who don't know. Fuel tankers are segregated and can haul multiple different liquids inside themselves. If the driver is absent minded, they could accidentally load the underground storage tanks at the station with the wrong grade of product.

Long story short, the driver had put the V-power in the regular tank and the regular in the v-power tank... John sent me a $100 Shell gift card AND gave my work the business to send a vacuum tanker out to the station to pump the fuel out of the V-power tank. My boss was pleased to get the work, and everyone who went to that station to get regular fuel was really getting V-power at regular price without even knowing it (for maybe a week or so).

Bottom line, my MCS' ECU adjusted to the performance level that it felt was safe for the fuel that was in it. As soon as I ran that tank out and put V-power back in it, all the power came right back.

 

^^^^
This man knows his fuel!

Good stuff, Tony. I appreciate it. Unfortunately, I'm still unclear whether, in your opinion, running water/meth injection would allow one to run a tune designed for higher octane gas. For example, assuming the tune was written for E0 93 gas and I have only E10 91, it's been my impression that water/meth would mitigate the difference. True?

 

kenosha, but have to go to lyons for E0

scott

 

Kenosha is close enough for a cruise!