any TT s550's on 93 and meth?

[bmoore]

I see a lot of numbers for E85 but not so much for 93 or 93 and meth. What kind of numbers would you guys expect with an automatic on pump and meth?

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[BlownOne]

You could set it up on 93/meth on lower boost with mild timing and be fine, but I wouldn't tune for the meth incase it fails. If the car is happy, once you spray at wot it will add in a few degrees of advance based on your parameters set by your tuner.

 

[Travis@boostworks]

We run it in our kits. Most of the time, like 25% meth/alky and 75% water.

 

[bmoore]

Why not 100% Travis? On ls stuff we've always tuned it to be fully meth dependent so if it fails the car will fall on it's face instead of grenade.

 

[5.0yote]

You rarely make any more power past a 70/30 mix so 100% will not net you any benefit as far as octane/power are concerned. IF your system is setup correctly you will have at least a flow gauge as well as other failsafe setup with aux input/outputs triggering safe modes (cut throttle, drop boost, run different map) etc. I am running failsafe on my setup that cuts the throttle pedal, and its pretty instant.

I also test it every tank of meth. =)

 

[Travis@boostworks]

Why not 100% Travis? On ls stuff we've always tuned it to be fully meth dependent so if it fails the car will fall on it's face instead of grenade.

Several reasons..

If you're that heavily dependant on methanol for fueling, then you need to be running direct port. Atomization and flow characteristics through the stock manifold makes for uneven distribution. So, a traditional single or dual nozzle won't suffice. At some point, it becomes expensive enough to do properly that you could buy a fuel system and run E85.

If you're running less methanol on a single or dual nozzle, then the meth not working isn't going to make it fall on it's face. Also, I wouldn't want to have to rely on my customer realizing that he/she needs to get out of the throttle. A few seconds of super lean at moderate boost is enough to break ring lands on cast pistons.

Also, I've seen enough clogged nozzles, failed pumps, and relay failures that I would never set it up to be dependant on methanol as a fuel.

We use water and a little meth/alcohol for evaporative cooling. Divorce the IAT sensor into the manifold, and let it see cooler temps from evap cooling. Also, it helps lower combustion chamber temps, valves, etc. It also keeps carbon buildup down. When we run our setup, IAT's stay within 5 degrees of ambient at 20+ psi.

Travis

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[bmoore]

Gotcha. So what kind of power could you expect your kit to make on 93 thru an automatic? With some meth for iat cooling.

Ive always found it odd how different meth is viewed between the ford and gm/corvette tuners.

 

[Travis@boostworks]

We typically make 750whp on 93 with good temps.

I view it the same on GM. We've seen a lot of horror stories with meth and LT1/LT4 C7's. It works well if you do port injection with a good pump, but most don't want to spend 1500-2k on doing it right.

 

[Roh92cp]

I run a small shot of meth single nozzle on my whipple's setup. I first tested knock with 93 octane gas and a 3.5" 13 psi and that produced knock in the 2-3.5 range spark advance was like 15 at full song. This is still considered with the same margins for the Whipple cal to pull timing up to 4 degrees. With meth and same gas and pulley I know see -2 to -1 knock and 18 advance spark and if it fails to spray I won't blow my motor as the whipple cal will pull timing up to 4 positive.

 

[Travis@boostworks]

The problem with that is you're relying on the adaptive knock strategy to keep you safe. This means that the engine still has to knock for the PCM to decide to pull timing back. On a stock engine at less power, that's a sound strategy. But, with double the cylinder pressure and cast pistons, that's not very wise. Does it work? Yes.. but, what happens if a knock sensor doesn't pick up the knock? Had a buddy here in Houston with another local tuner who used the same strategy with nitrous. A year and 1/2 later, the engine broke 2 ring lands. Rebuilt the engine, and went to tune again. Turns out the knock sensors weren't doing their job.

Just food for thought. Injection should be used for IAT cooling. Not fuel.

 

[Roh92cp]

The problem with that is you're relying on the adaptive knock strategy to keep you safe. This means that the engine still has to knock for the PCM to decide to pull timing back. On a stock engine at less power, that's a sound strategy. But, with double the cylinder pressure and cast pistons, that's not very wise. Does it work? Yes.. but, what happens if a knock sensor doesn't pick up the knock? Had a buddy here in Houston with another local tuner who used the same strategy with nitrous. A year and 1/2 later, the engine broke 2 ring lands. Rebuilt the engine, and went to tune again. Turns out the knock sensors weren't doing their job.

Just food for thought. Injection should be used for IAT cooling. Not fuel.

Thanks Travis, I was under the impression the knock logic was pretty safe and accurate and reliable. I see your point for sure though.

 

[Travis@boostworks]

I mean, it works.. But, I prefer to use knock retard as a last resort type thing. You know?

 

[Bartly]

The problem with that is you're relying on the adaptive knock strategy to keep you safe.

Pretty much what I do whenever driving given that I only have 91 octane to put in my Procharged GT and see +knock on all WOT runs.

I've been reading about water meth injection for a couple days now and it seems like a good solution to make my knock sensors go negative instead of always reading positive (+3 to +5) at WOT. Seems like about half the guys who appear to have any knowledge of meth say to tune the car without meth so the knock sensors can do their job in case something goes wrong with the meth injection system. The other half say to tune for the meth so the car is adding timing to optimize the meth in the combustion. It's kind of hard for me to figure out what is a good path to go down with the tuning. Being that the car is my DD I just want my engine to live a long and happy life. The three options I see are:
1. Leave it as is and just hope it always pulls enough timing for the +3 to +5 knock that happens during WOT events.
2. Leave the tune as-is and install water-meth and watch the knock go negative and the spark advance to where it can. If something goes wrong with the meth injection the knock sensors should do what the are doing now and pull timing when I'm back to +knock.
3. Install water-meth injection have a another custom tune written to make it perfect for the water-meth/fueling. I just question what would happen in this situation if I end up on a WOT pull and don't know that the water-meth system isn't working correctly.

Sorry, I'm pretty naive on this stuff, just hoping others who know a thing or two can help me learn what would be a good direction to go. Also sorry to sidetrack this thread as I'm supercharged, not turbo'd, but guessing it's all kind of related.

 

[bmoore]

That's what I was talking about. A lot of reputable gm tuners like ecs will tell you it's better to be fully dependent that just slightly dependent because if it fails under boost you would rather see 16 afr than 13 because at 16 it will spit and stumble and you'll get out of it but at 13 you'll never know until it kills itself. I believe what Travis is saying is be neither. Just use it for cooling and don't let the pcm add timing, just make it where it won't pull tim ing for high iat's.

 

[Travis@boostworks]

Yeah, we blew up a few ECS / Meth C7's early on in the learning curve. Lol

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