Nozzle placement and IAT sensor spacing

[BDC]

Good info, good to see someone on here is showing what I've been saying for a while now, put the nozzles as far from the TB as possible. There have been other tests years ago that proved the further away, the better the temps due to the amount of TIME needed for the Meth to cool the charge.

Now that you can see the temps, you can determine if you need bigger nozzles or more pressure. :biggrin:
70 degree cylinder temp (after injector sprays gas/ethanol/methanol) is the cold threshold so 100 degrees at the TB still has some room left for more Meth. :wink:

The Hot Air pipe is too close to the cylinder.

We'll see what it does IAT wise with this setup. I changed one of the M10's to an M15 so now I'm lookin' at 25gph @ 100psi total which, when cranked up on Julio's system, ought to sit around 1800-2000cc of methanol injection. I put the M15 in the latter of the two spots on the hot-air pipe. Curious to see what happens! Wondering if I ought to experiment with moving that nozzle closer to the first one further upstream. May do it at some point to see if there's an effect on IAT's at the same boost.

Also wanting to see what IAT's will be at various boost levels in this nice 103*F Texas heat while it still lasts!

B

 

[bison]

Good stuff!

My question is why did the setup suddenly work when the nozzles were moved away from the throttle body and placed up stream? There something having to do with time to flash the alcohol or something? That's my only guess. When I had them in the hotair pipe just aft of the TB, at just 1bar of boost the IAT's reached over 150* and the motor rattle canned loudly. With them moved up stream, the temps were a few degrees below ambient at the same boost and it ran terrific. What gives?

B

If you give me your email ill give you a couple possible reasons as to why the IAT was reading high.

 

[Alky V6]

Very interesting stuff, Brian.
I get the impression that many are trying to get the intake air temps as cold as possible. 70 degrees F. I suppose that has to do with the relationship of mixing the alcohol with gasoline. Just to throw in my experience burning pure methanol, most blown tuners shoot for an intake temp of around 160-180 degrees to properly prepare the mixture for the best complete burn. With intake temps too cold, not all of the alcohol is burned during the normal combustion event. You can actually run into a lean burn situation with a mixture that starts out too cold before compression and combustion, forcing one to richen the mixture to make up for it. Maybe that's what is happening when you have the nozzles mounted too close to the chambers? Not enough time for the alcohol to do the job and actually running into a situation where the mixture ends up acting leaner than expected.
I know in my case, the engine runs best with coolant temps at the very least at 160 F, with the engine running even better at 180-200 F. That gives me an intake runner, cylinder and combustion chamber temp that helps to preheat the charge. There is a range of intake air temp that should be targeted. Too cold, at least in the situation of a pure alcohol engine is not good.
Another interesting twist that further confuses things is that I port inject all of my fuel and nitrous, yet get away with running a comparatively lean mixture (10.8-11.3:1 a/f). My meter reads out gasoline numbers. I also use an ambient temperature air/liquid intercooler. The intercooler will eventually allow even higher boost numbers than what could be achieved with alcohol and no intercooler.

It all comes down to this. Alcohol fuel likes to work within a particular temperature range where it comes to intake charge temperature, cylinder temperature, temperature gained during compression and temperature during combustion. The trick is finding that range. It sounds like you're on a good road to figuring that out.
Just remember, you could overcool the charge and run into problems.

 

[Alky V6]

What a lot of people don't realize is that methanol cools during two totally different events. The first event is the cooling that occurs during vaporization. This occurs at a relatively low temperature. But this is only part of the cooling effect that methanol gives you. AND, vaporized methanol does not guarantee a complete burn.
The second event is the cooling of the charge that occurs during actual methanol molecular dissociation. For this event to occur, a particular temperature must be present. This temperature would ideally occur partially during compression and into combustion. Temperature control of the cylinder and chamber is critical to getting the proper target temperature to occur.
If part of the methanol has not dissociated during the compression and/or combustion event, two things happen. First, you lose out on the cooling effect that part of the mixture would have contributed AND you lose out on the combustion of that part of the mixture. Methanol must be dissociated before it will burn.
If part of the methanol mixture has not dissociated in time for combustion, then the mixture charge as a whole will act like a leaner a/f charge.

 

[Alky V6]

The more chance the methanol charge has to finely atomize, and better yet vaporize before it enters the cylinder, the more chance that most or all of it will properly dissociate in preparation of the normal combustion event. Just keep in mind that a proper temperature range needs to be present for each of the events to properly take place.

 

[Alky V6]

Brian. Sorry for not getting back to you on FB. The way I read the thread, you had it pretty well figured out. I don't think I could have added anything to what you've already come up with. Besides, these guys here have much more experience with mixing methanol with gasoline. I'm of the thinking, why mix a superior high performance fuel (methanol) with gasoline? You just ruin it.

 

[BDC]

The more chance the methanol charge has to finely atomize, and better yet vaporize before it enters the cylinder, the more chance that most or all of it will properly dissociate in preparation of the normal combustion event.Just keep in mind that a proper temperature range needs to be present for each of the events to properly take place.

^^^ Bingo! I think that's it. That may've been the problem I had initially when I had the two nozzles installed a few inches in front of the TB before moving them well upstream. Thanks, Don.

B

 

[BDC]

If you give me your email ill give you a couple possible reasons as to why the IAT was reading high.

Sure, Bison! Would love to get your input. I'm still experimenting with this setup and the more advice I get the better off I am, I s'pose. My email is bdc@bdcmotorsports.com.

Thanks,

B