Actually you've got that slightly wrong. There is no "af mixture" in the sense we think of it in gasoline engines. They run a super high compresssion ratio and tons of boost, but they are cramming straight air into the combustion chamber, and then squirt in the fuel when it's time to ignite. The fuel then instantaneously ignites.

 

hmm..how bout this...u squirt in gasoline and diesel.....the spark ignites the gasoline...the explosion creates the amount of pressure needed to ignite the diesel?....

 

diesel engines also have no throttle plates.

 

Wow, this thread has turned into a wealth of mis-information.

Lots of good info, some bad.

But lets return to the original question, has anyone tried this, for example, as a mixture? Perhaps 5% diesel and the rest gasoline? I'm sure our seals will love that, based on the lubricating properties of diesel

 

Here here!

Quote:

Lots of good info, some bad.

I'd say it's the other way around, but...

Quick points for those who haven't looked at howstuffworks.com as SonicRaT suggested:

Diesel is _easier_ to ignite than gasoline. It's ignition timing is determined by when it is injected into the cylinder. It doesn't exactly burn instantly, but that's a little more detail than I should get into here.

Diesel compression in road-going heavy duty trucks is generally about 18:1. The high cylinder pressures this causes, high boost, and fast fuel burn (not knock) are the main reason they are built so sturdily.

Cetane and octane numbers run in opposite directions. Higher cetane means lower octane, and vice versa. (this is a simplified explanation and is true 99% of the time, and mostly true all the time )

Using diesel in a rotary would not mean it has to be built more sturdily. Just make sure you don't use enough diesel to cause knock. If you do knock, making it stronger won't help much.

Quote:

hmm..how bout this...u squirt in gasoline and diesel.....the spark ignites the gasoline...the explosion creates the amount of pressure needed to ignite the diesel?....

Actually, the diesel would be ignited by the spark. The gasoline is actually harder to ignite. The company I work for uses diesel injection to ignite natural gas. Natural gas has an octane number of about 130, so it won't ignite from just the compression ratio and boost of a diesel engine.

Cheers!

 

Thank you, glorthu

 

Also to add to this, Diesel doesn't mix with gas. Diesel is heavier, so even if you only put 20% diesel in, the next morning when you hit the key, BAM nothing but diesel. I think that would be one slimy bitch. And than after you lost compression from gumming up the seals in the engine, it would be very hard to clean up on the tear down. I was a diesel mechanic for a couple years and that is a different beast right there...... Ick

 

Now THAT is some relivant info! Thanks!

 

Might I recomment 96+ Octane, Turbo rotarys seem to love it

 

The lower the octane on a N/A, the better (at least, not too low, heh)

 

they should start producing 84 octaine at the pumps, amd price it realy cheap. that'd make up for us needing so much of it. lol

 

Hmmm... I don't think I agree with the part about the diesel separating out. Gasoline and diesel are both just blends of hydrocarbons (with some other addatives thrown in). I'm pretty sure that the diesel/gasoline blend would remain in solution for quite a while (assuming that you aren't going outside the range of solubility, whatever that might be for these fluids). You wouldn't want to store a car with any significant quantity of diesel in the tanks though, since diesel evaporates much more slowly than gasoline.

Come to think of it though, there may be some problems getting the diesel portion of the fuel to vaporize. You may end up gumming things up and building deposits because of that... I would guess it's not worth trying this in a rotary, what with carbon lock being a problem even with regular gas.

 

In cold weather I could see a lot of problems, specially with the waxy part seperating out.

But I do think that Radial GT has a valid point, the Diesel is on a completely different level of cracking, I dont know, however, if normal temperatures are going to seperate them even nominally over the course of a day. However, in the long run, if diesel does settle out like that, it will eventually cause the possability of detonation when theres too high a concentration of it.

Come to think of it, if you could find diesel with a given octane rating and know that it would keep that constant, perhaps all it would take to run it would be turning down the timing? However, I doubt the long run effects would be positive, with the posibility of high concentrations doin strange things to gasoline engines. (Maybe gumming up fuel injectors, fouling spark plugs, voting for Buchannon, and messing up the fuel filters?)

 

This is not even remotely true. Who told you that?

 

Actually, diesels don't have a throttle on the intake air. A diesel engine doesn't care if there is excess air in the combustion chamber. The richest a modern diesel should ever run is about 17.8:1 A/F ratio. Is they run richer than this you start seeing black smoke come out the exhaust (which is why this approximate A/F ratio is called the "smoke limit").

The diesel fuel is injected into the cylinder and burns as it diffuses into the air. Any extra air doesn't harm combustion. The diesel flame is basically like a candle, where you have the fuel coming up the wick and evaporating, and then burning when it gets far enough from the wick that there is oxygen available. The diesel flame isn't affected by extra air in the combustion chamber just like the candle isn't affected by extra air in the room.

 

What he said ^^. And I know someone with a turbo diesel truck. He explained to me that this is the reason turbo diesel engines do not require BOV's.

 

Wow, guess I learn something new every day.

I stand corrected.

I was complaining about mis-information earlier, guess it was my turn to put some out :-p

 

Tofu, I'm not sure about diesel fuel, but I found that CD2 makes a lead substitute that seems to work well for lubrication. I'm running a pretty modded setup, so you'll have to do you own chemestry to find out what works best, but I found using 4oz to 5 gal of gas works well for me. I called CD2 about this product and it doesn't do much in the way of octane boost, but it provides a thin layer of protection over metal valves (should do the same for apex seals). The only issue, if anyone even cares, is that it's labeled for offroad use only. I haven't noticed any problems on my plugs, they look good, my O2 sensor it still reading fine, doesn't seem to affect much of anything, since I don't have any cats on it, i'm not sure what happens to them. I you want to get really picky though, there is a product out there called Lead Supreme 130. It's real tetraethyl lead, which will give your O2 sensor and cats issues, and ofcourse, you'd have to ignore the "use unleaded fuels only" stickers. I don't know if this helps you out any or not, but that's my 2 cents.

 

i was one of those mistaken people who poured diesel into their cars. I was almost empty and found a couple of cans in my shop. Poured it in.. it was about 3-4 gallons. Car ran with it. I noticed really fast spooling of the turbo, but had crazy rough idling.

 

Cool I should get some diesel in my tii. I can tune the rough idle with my Microtech.

 

uh... i still don't think it's a good idea. but whatever floats ur boat.

 

pm'd u VietFC