DSMTalk Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum banner
Cancel
Create thread New Garage Forums

Import Power Online propane injection kit

1 reading
Jump to Latest
121 - 140 of 358 Posts
#123 ·
Funny how the good threads always die young... :D Any more numbers on this? Anyone else take the plunge and install it? I'm looking to do this next month, but I am hungry for more data, not related to turbo diesels... :)
 
#124 ·
95GSXracer said:
Funny how the good threads always die young... :D Any more numbers on this? Anyone else take the plunge and install it? I'm looking to do this next month, but I am hungry for more data, not related to turbo diesels... :)
Click to expand...
I have gone through all the threads on this topic on just about every car forum, and I have decided to "take the plunge". ;)
Hopefully I'll have some report next month. I'm going with a different kit though.
 
#126 ·
95GST said:


I have gone through all the threads on this topic on just about every car forum, and I have decided to "take the plunge". ;)
Hopefully I'll have some report next month. I'm going with a different kit though.
Click to expand...
Likewise, although I have all components in hand except solenoid- I will have a toggle actuated solenoid for in car control/safety, plus the Hobbs actuated solenoid.

I will be injecting at 20psi, pre turbo, into the bottom of the BOV tube. Most of the diesel kits inject pre turbo. This seems like a good way to avoid a potential boost leak, and keeps less pressure in the propane line. I noticed that folks running 80 psi (60 psi net at 20# boost) can only open the valve 1 out of 6 turns or less, so with 20 I will hopefully be able to run the valve about half open and have a lot of fine tuning capacity.

The solenoid should come today and hopefully I will complete the installation this weekend and report back soon after.

See my tank mounting piece on the other new propane thread in Parts Talk.

Joe
 
Save
Reply Quote Like Like
#127 ·
why would you want to inject pre-turbo? one of the main reasons for shooting propane is to cool the intake air...it will be much more affective after the turbo to aid your IC. you will be able to run more boost, get less detonation, and the higher octane fuel will make it into the cylinders easier. you will not get the cooling effect of propane before the turbo because it is the liquid to gas reaction which absorbs heat...
 
#128 ·
Greg- the way I see it, pre turbo is same concept as CAI. In either case (pre or post turbo), the net results should be the same. There was a good thread on CAI a month or two ago.

Joe
 
Save
Reply Quote Like Like
#130 ·
Be careful of pre turbo injection. As we all know, turbos spin at around 100,000 rpm. Even a small water droplet or small foreign object that gets introduced to that spinning wheel, fogetaboutit...you will have blade parts everywhere...

Just info to think about...
 
Save
Reply Quote Like Like
#131 ·
Before modern EFI, most gasoline turbo cars were draw through types. They worked well, except for the fact that the a/f going through the compressor would wear the fins away. THe compressor wheel wouldn't make it 60,000 miles in some cases. I don't think propane being a gas is going to cause any major problems. Now, water injection before the compressor, yeah definatley.
 
#132 ·
i just asked my uncle about this, he is a mechanical engineer. here is what he has to say. (when he says intake he means UICP) it sounds like there are a few more factors that have to be taken into effect...can anyone expand on this?


Hi Greg,

Nice to hear from you.

Unfortunately there is no easy answer. Taking in on the surface the best
place would be to inject it after the turbo because of the heat
differential. This is complicated by a number of factors mainly the pressure
and velocity of the air after the turbo. I suspect that with the higher
pressure after the turbo that the air velocity is less potentially giving
the propane more time to cool the air. The problem with this approach is
that with the lower velocity the propane may not mix as well. In addition
the cooling aspect of the propane comes about by the rapid expansion of the
gas. It sucks up the heat energy in going from the liquid phase to the gas
phase, Grandpa could tell you alot about that, being in the air conditioning
business all his working career. That is the concept that air conditioners
work on. The higher heat would cause the propane to try to expand more and
thus more cooling, but this would be offset by the pressure.

Putting the propane in the intake would provide more mixing, a bigger
pressure differential therefore more cooling. The only downside is the
velocity of the the intake not providing time.

After going through this a describing the pros and cons the intake is
probably the better side. Be extremely careful!!!! I can not emphasis this
enough, propane is heavier than air and could fill a garage that you are
working without you know it. Then the slightest spark could set it off.

On top of this the process of going through the turbo and being heated and
pressurized could cause a flammable condition prior to even getting into the
cylinder.

Have a good day.
 
#133 ·
Greg- thanks for looking into this. Your Uncle makes a lot of good points. The biggest issue seems to be the possible risks of heating and compressing the propane by injecting pre-turbo.

As to heating, the LICP does get kind of warm when spooling a lot. I think some of that is heat transfer through the midsection of the turbo from the turbine, but some of the heat does come through compression of the air from atmospheric pressure to over double atmospheric pressure.

However, since the propane is at 100 to 200 psi in the tank depending on ambient temperature, the compression back to 20 to 25 psi seems negligible by comparison. Plus, the cooling affect of injecting propane just before the compressor (Like the ATS diesel propane systems) should actually decrease the temperature of the air entering the LICP significantly.

The issues about pressure and velocity related to mixing of the propane into the air are beyond me. Maybe someone can shed more light on this.

By the way, I think one of the reasons some (or all?) of the diesel systems inject preturbo has to do with their boost levels. I surfed some diesel forums and found that their stock engines can handle 40-45# of boost, and some of the highly modified diesels are running 80PSI with a twin turbo setup. There would not be enough propane line pressure to inject post turbo at average ambient temperatures, unless a bottle warmer was used at any time the temp was less than 90* or so. Plus, they inject much more propane than gas systems, generally 3 to 5 parts diesel to one part propane. I suspect that based on folks running propane tanks in gas engines for months between fillups that they are using a lot less propane.

Thanks again for your Uncle's good information. I may hold off on installing pre-turbo until I learn more.

Joe
 
Save
Reply Quote Like Like
#134 ·
I agree that in order to get the maximum benefit from the cooling properties you want to inject the propane where the air is the hottest, which is after the turbo. The "rule" we need to keep in mind here is that the rate at which an object changes temperature varies directly as the the difference between the object and its environment. So what this says is the greater the difference in temperature, the faster the rate of heat energy exchange. If you watch the curve for an object changing temperature it will be steep at first and level off with time as it approaches the temp of whatever is changing it. Take the thermometer out of the fridge and watch how fast it drops in the first minute, while it seems to take forever to come up that last couple degrees.

This same "rule" comes up when you talk about ICs and cold air intake on turbo cars...
 
#135 ·
When we talk about cooling capacity it seems we need to look at the ratio of propane to air. With a few pieces of information from Erik's original post I think we can work towards an estimate of the ratio. Here is an excerpt of Erik's original post:

"At 20# I was seeing a steady .94 volts and timing was so-so dropping to 10* and only rising to 17* by redline.

Now time for some propane.

First pull the car felt smoother. I was logging O2s first and the propane increased that number to .96-.98. EGTs dropped from 1550*F to 1410*F. Another pull to check timing and I see that timing drops to only 14* and rises to 22* at redline with no dips or plateaus. Over the course of about 4 pulls I pull out a total of about 7% fuel with the AFC and get the EGTs back to 1550* and O2s back to .94 across the board. "

This seems to show propane is about 7% of the fuel(1:14). However, propane is a gas once it leaves the tank, not a liquid, so it apparently displaces more air. I read that propane in liquid form is 1/270th of its volume as a gas. If this factor is ignored and we assume 11:1 air/fuel ratio at WOT it looks like the ratio of propane to air is only about 1:154 (1:11x1:14), not enough to cause a significant temperature change.

But again, the fact that propane is a gas not a liquid must have a major impact. If we consider the 270x expansion, does that mean there will be more propane than air in the mix? That does not make any sense to me because how would the engine run on so little Oxygen?

I am confused about this- can anyone shed light on this? It would help determine if propane's anti detonation benefit is primarily from temperature decrease, octane increase, richer fuel mix, or some combinastion of these. I suspect richer mix is only a small factor since Erik dialed it back to the same O2 reading as pre-propane yet still saw benefits. I also think the 110 Octane impact is minimal if the propane is really only 7% of the fuel as seems to be the case. So I guess this leaves cooling as the greatest benefit?

I also appreciate the information on rate of heat exchange- that does seem to indicate faster exchange post turbo, but since the temperature change preturbo is still significant, probably 100* or more (My IAT's are near ambient due to CAI, versus propane at minus 45*), I think there will still be significant cooling effects pre turbo.

Thanks for all the feedback,

Joe
 
Save
Reply Quote Like Like
#136 ·
Even if the propane is nice and cold, I just cannot imagine it coming from a small line and cooling 4 hot cylinders with any significant effect.

I think what happens is the propane gas mixes with the intake charge, and it makes the air fuel mixture harder to pre-ignite; until the spark plug fire, serving as a knock reducer and allow you to run more boost.
 
#137 ·
I dont have the numbers handy, but I was surprised when poeple measured the cooling effects of water injection, and that comes out warm... But I have to also agree that the main benefit is high octane, like IPO keeps saying. But any cooling effect is welcome, no matter how slight it may be. Even if the ratio of propane to air seems small, its still high comapred to fuel, and even if it wasnt, its still mixed throughout the mixture acting as a buffer either way...

There was just a show on tv not too long ago where they put a propane injection kit on a cummins turbno diesel and picked up 70 hp. I think they added over 200 total in the show. Now if only one of those shows would do a spot on a dsm... :)
 
#138 ·
Well, if I boost without water and touch my intake manifold it will typically be pretty warm. I'd say at least 120 degrees F, as I can only hold my hand on the back of the intake manifold for 5 seconds or so before it becomes painfull.

Turn the water on, and the intake manifold is pretty chilly. Like filling a glass with cold tap water, 30-40 degrees F.

SO, if you're wondering if propane provides cooling, and don't have the measuring equipment then do a pull with propane, and without propane and see if their is any change in manifold temp.
 
#139 ·
danl said:

SO, if you're wondering if propane provides cooling, and don't have the measuring equipment then do a pull with propane, and without propane and see if there is any change in manifold temp.
Click to expand...
Sounds like a good idea to me. Greg, how about trying this and letting us know? Thanks.

BTW, here is a quote from an engineering forum discussing a dedicated propane system (conversion from gas): "Since propane vapor displaces about 5 to 8% of the incoming air, "
http://www.eng-tips.com/gviewthread.cfm/lev2/6/lev3/35/pid/71/qid/37133

Thus, if we are injecting 1 part propane to 14 parts fuel (7% per Erik's post) then propane should be far less than 1% of the air, right? I think I like Dan's solution better than all these calculations... ;)

Also, I am still up in the air about injecting pre or post turbo- I have held off on installing my system until I decide this.

Thanks,

Joe
 
Save
Reply Quote Like Like
#140 ·
Save
Reply Quote Like Like
121 - 140 of 358 Posts
About this Discussion
357 Replies
38 Participants
Last post:
97silvereclipesss
DSMTalk Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum
posts
2.3M
members
104K
Since
2000
A forum community dedicated to Mitsubishi Eclipse, Plymouth Laser and Eagle Talon owners and enthusiasts. Come join the discussion about performance, turbos, builds, modifications, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
General DSM Tech and Tuning Help! Tech Newbie Questions Forum Body Tech and Appearance Electronics Tech