legacycentral bbs

I'm looking for a general concensus on this. Would it be safe to run 87 octane at strictly wastegate pressure? For our cars, this is 6 psi, with the factory VF11 correct? With most other bigger VF turbos the wastegate pressure is 7. What do you think? Please, everybody who sees this, please answer at least this part.

Part 2 to the question. Would it be safe to run 87 octane at wastegate pressure, while running 50/50 water and methanol injection using a MAF signal as the trigger?

Part 3 to the question. While running water methanol injection as above, but beyond wastegate pressure, would 87 Octane + the water meth injection be equivalent to or better than running straight 93 octane and no water meth injection?

To be clear, this is not something I'm doing. I plan on adding a water/meth injection kit, and in doing the research I discovered the Snow Performance Wastegate Solenoid, which allows you to use a Water Meth failsafe device to bring your boost all the way down to wastegate pressure if you run out of water/meth, or if the pump fails. I am considering buying this solenoid in order to make a cheap max MPG "switchable map" by turning it on to run only wastegate pressure. If this were combined with the hybrid stock BCS + MBC that some of you have worked on in the past, you could have 3 power levels to dial in at any time.

Just use 92....87 period is not good to boost in.

My wife filled my car with 87 once when it was stock. Knocked like crazy at anything more than very light throttle. I don't think I saw more than 3 or so psi at very light load without horrendous knock. I siphoned it into another car because it was too bad to run through the tank.

Like mentioned above, if you're boosted 87 is bad period. Some new direct injected turbo cars can run 87, but that involves a fuel system that costs more than most of our cars are worth.

So even at low boost and low compression 87 octane pump gas is a no go. How about with water meth injection? I've read that 93 octane pump gas + water methanol injection allows people to run tunes that make more power than they can with 116 race gas.

I don't understand why you even want to run 87?


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robertpaige wrote:I don't understand why you even want to run 87?


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To be a cheapo.

And spraying water meth everyte you wanna accelerate enough to keep up with traffic is cheaper?

From what I understand, 1 gallon lasts a good bit, and you can get one gallon of the 50/50 windshield washer fluid for less than $2.00. (I'm not sure about this price. The cheap stuff is like 30% Methanol.)

Other people's experience running Water Meth injection say that one gallon lasts about 3 tanks full.

Even if it's closer to one gallon of water/meth per tank full of gas, the difference in cost of 16 gallons of gas at $4.19 as opposed to $3.85 (current prices here) is 5.44. The gallon of Water Meth mix would cost me no more than $2.50, provide a higher boost in effective octane, and provide even greater benefits than running 93 octane pump gas, such as reduced intake air temperatures and cleaning out the combustion chambers of carbon deposits.

Anybody with experience running water / methanol injection want to chip in? Am I totally off the wall in my thinking here?

idk, you may be able to mix up some kind of concoction, but our ECU map is designed for premium fuel. I wouldn't begin to trust 87 and some methanol mix to drive well…

Sounds like a bonkers idea to me

This is an interesting line of thinking. I agree on the stock ecu, it would probably be a no go, but with a standalone that could control a meth kit? I think it could work. Economics would go out the window of course

Water Methanol injection comes with its own controller that injects a preset amount based on either a boost signal from the turbo or a MAF signal, or an OEM or external MAP sensor that you add in. I think the key to using it for fuel economy and savings on premium fuel is driving the injection off our factory MAF as opposed to using one that runs off the boost signal. It would have to be injecting Water Methanol mix at part throttle even off boost to prevent any possible detonation.

Part of the idea I had was to use one of these wastegate solenoids setup to basically prevent the turbo from building boost past wastegate pressure at the flip of a switch. That way, whenever I decide to run 87 Octane for savings, I can't go past 6 or 7 PSI. If I run the water meth injection off the MAF while I do this, then there should be no detonation, savings on the cost of fuel, AND increased fuel economy.

Sounds like a lot of work to save a few bucks per tank of gas. But it does sound feasible. Just keep in mind that if something happens, like the water/meth pump going out, you will be in for a very bumpy ride. I'd say go for it and see how it works. People on this board have executed worse ideas on these cars.

Well you have to understand that it also opens up the possibility of having the best of both worlds. Not only can you use it for increased fuel economy and savings on premium fuel, it also opens up the possibility of extra power. Ideally I could do this on different tuning maps. As far as the risk of pump going out or running out of meth, I could always connect failsafe to complete the circuit on something that retards timing, in addition to the wastegate solenoid. BTW, I don't mind spending on upgrades to the vehicle. It's the ridiculous price of gas that bugs me. Anyway MSD DIS-2 might be the ticket to retarding timing when necessary, with the added benefit of a more powerful ignition, possibly further improving fuel economy. Then again a PP6 could accomplish that as well couldn't it? It would probably be cheaper too, though quite complicated to install.

If you aren't intimidated by medium difficultly wiring and just reading a diagram, the PP6 install is fairly easy. It dosent connect to that many wires.

Just get a Hydra


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I would only need it for the timing retard. Have a Robtune computer on the way and have an Apex'i Power FC ready to install, if ever I should decide to.

OK so what's this I hear about Water/Methanol injection messing up your Air Fuel Ratios, at least for tuning and logging them? So how are you supposed to tune with water meth injection?

Rod Grosvenor has run meth in his legacy. He's running a boosted ej22 with a unichip. He doesn't get on the bbs much, but is on facebook and you could try sending him a message.

Regarding the MSD or PP6 to retard timing. When you retard timing you decrease fuel economy. I'm not saying what you want to do can't be done, but trying to get the control of everything to work properly is likely going to be a huge pain in the butt....if you can get it to work at all. IMO, it's not worth the hassle and risk of something going wrong. Plus, even if you're doing the work, tuning, etc. What is your time worth? Is it worth the few extra dollars per tank?