Club 80-90 Forums

I understand that liquid injection systems have been tried.
This would be very usefull on a turbo charged engine.
As there would be great cooling effects, better than an intercooler.
What are the downside. Manifold explosions?


I know LPG has an octane rating of 102
against 95 for petrol.

Schick did a turbo charged DJ engine with 163hp with compression ratio 9.0 - 1
would it be possible to run a turbo charged stock DJ compression ratio 10.5 - 1 on LPG.
Could control ignition with Meqersquirt or similar

There was a company called IKOM who used to make a "wet LPG injection" system, the technology was not up to much though as they had hellish problems with the LPG pump and you had to have your petrol injectors calibrated to the LPG ones to make it work, they abandoned the idea long ago.

We convert many vehicles to LPG turbo, twin turbo, some very high spec motors including Porsche air cooled, the best at present for turbo and high spec engines is the sequential injection.

[quote="Pickles"]I understand that liquid injection systems have been tried.
This would be very usefull on a turbo charged engine.
As there would be great cooling effects, better than an intercooler.
What are the downside. Manifold explosions?
Response:
Strangely enough my friend rigged up a very crude (some would say suicidal) system on his top whack 50MPH ex council local sevice bus and even with it's hand and intuitition controlled flow valve system did achieve that extra hill climbing ability when towing a boat. The vehicle did overheat however to the point where periodic rests were required to save the entire engine from destruction. Manifold explosions are comon on performance or malajusted engines and the volume of the average engine is IMHO not big enough to do any more than remove your facial hair and promote that ruddy farm worker complexion. On the KISS principle I would suggest that big normally aspirated engines or smaller boosted engines with time proven production standard setups are the way to go. I like my friend and am glad to see that he has scrapped the vehicle and dumped the length of garden hose, calor gas bottle, manual control valve and length of valve actuation washing line cord to the tip.
Cheers
Wolfie

David,

This is the pre-eminent company in the liquid LPG injection stakes i think: don't know if you've come across it yet...

http://www.lpgli.com/index.html

Liquid injection seems the way to go.
I will contact them.
Interesting that 13 to 1 is ok for LPG 103 octane.
I assume 10.5 to 1 (2.1 dj) turbo charge would be fine on LPG

Have done 100,000 miles in my 2.1 on LPG now with a Vapouriser system.
No LPG related proplems.
Have run 13 deg Advance.

I assume 10.5 to 1 (2.1 dj) turbo charge would be fine on LPG

Well, not saying what sort of boost levels thinking of there David makes me ? a bit ?

But a good experiment keeping it down to just a few psi (5?)

So, I think whats imp. is not just detonation threshold but peak and mean cylinder pressures too...

13 deg adv, sounds good if it'll stomach that at full bore 2 to 3000 rpm without detonation and vac and centr. advance is working properly as well

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That Liquid LPG system sounds very interesting, but also very costly

HarryMann wrote:

I assume 10.5 to 1 (2.1 dj) turbo charge would be fine on LPG

That Liquid LPG system sounds very interesting, but also very costly

I say HarryMann! Wouldn't it be better to uncomplicate the whole set up and go back to the roof rack mounted gas bag? You could then get youself on a cheap rate domestic gas tarrif and simply run a garden hose down the garden every now and again to top up. If you were worried about the smokeys and tax man you could secrete it in one of those big roof boxes. Maybe range might be an issue though!
Cheers
Wolfie

Liquid injection is too much hassle than its worth, ys it could have good benefits, but if there was a big one the manufacturers would have solved the issues quickly..
Yes it would be beneficial to hipo turbo engines, but the market is small and those engines have the "traditional" methods of charge cooling so dont benefit much from liquid....
A full throttle system (on a turbo motor) could be worked and thats where the biggest benefit would come... as we discussed a couple of years ago Dave...