Wicked NoZ

[xud9te]

Hi,

My friend has been asking me about adding 'noss' to his merc 2.5 IDI.

I have been telling him that unless you are really overfuelled then it will do nothing as there is no fuel to burn.  Its a non turbo also, so there is no LDA type device as such to perform mixture enrichment under pressure.

Its got an inline 5 cylinder Injection pump.  I suggetsed getting the turbo version of this pump as it may have a fuel enrichment device, but wasnt too sure.  You could then use a solenoid to push the 'LDA' when the Nozz is active.  

Any other ways you guys could see to increase fuel just when it is on?  There is no point increasing baseline fuel only to go around ith plumes of smoke until the system is activated.

How much extra pressure would the N20 cause in the inlet?  Enough to push on an LDA?  I wouldnt think so, but have not ever found out.

One other thing, I assume that as all N20 does is to add extra air, there is no chance that it could cause early combustion (i.e. on the upstroke) in a diesel is there?

Cheers
Greg

[xud9te]

Hi,

Just been reading about adding propane to NA IDI's in this post from stewardc:

http://vwdiesel.net/phpBB/viewtopic.php?t=3699&postdays=0&postorder=asc&highlight=nitrous&start=15

I was thinking of adding propane as the fuel source alongside the N20 injected into the manifold.  It seems that as the Propane combusts at 500 deg c, it will be ignited by the high temperatures from high compression ratio on NA idi diesels before TDC.  I calculated that the temp in a 21:1 ratio engine will be around 730 deg c at TDC (lower in real life due to heat transfer to cyl walls etc.) and had always thought that it was around 600 deg c, so that is about right.

- offtopic
(For an 18:1 engine it will be 594 deg c at 0 deg c ambient at best, assming losses could be around 450 deg c or less when cyl walls are really cold)
- /offtopic

Now, if propane combusts, why does the water/methanol injections not combust?  I assume that adding the water alongside the methanol (fuel) keeps the combustion iof the methanol to a minimum or none till just at TDC through heat absorbed in evaporation?  

Methanol reaches its critical point at only 240 deg c, so why does it not start to combust before TDC?  

So I was thinking, could one not use a healthy dose of methanol/water injection at the top end along with N20, the methanol providing the extra fuel?  or for that matter, propane and water?  All 3!

[jtanguay]

lots of people use water injection with small amounts of methanol and practically no issues.

at low rpm there will be issues of pinging by sending the methanol into the engine, and this is probably because the methanol has a chance to ignite before TDC.  when the engine is wound up to around 3k rpm the methanol being sent through doesn't have as much time to burn before TDC.

now if you were sending a gas such as methane through your system, i'd watchout.. very volatile and would probably detonate before TDC in every situation.  but who would do that? hehe!  propane on an IDI should be fine at high rpm, in small quantities.

[xud9te]

Methane?  Sorry, I didnt mean methane at all.

So you think that the reason that the methanol doesnt ignite before TDC in say a 50-50 mix is that it just doesnt have time to do so at 3000 rpm?  Interesting.  I will have to work out the burning velocity of methanol and see if it could.  I suspect it will still be able to ignite and burn at about 2/3rds piston travel up the stroke in theory.

One thing is for sure, it doesnt actually cause premature bang anyway...