LPG tuning

[100SRV]

Hello,

meant to put "LPG tuning"...

a friend has a 2.5 litre Land Rover engine running on LPG or petrol and he complains that it lacks power when on LPG. I don't think he is running enough ignition advance on LPG to get the best from the fuel. Can you recommend any reputable LPG experts in the West Midlands whom he could visit for advice or assistance?

100SRV

Edited by 100SRV on Friday 10th June 05:21

[blitzracing]

You could try RPI engineering,(Norfolk) they sell an ignition amp that allows you to switch between petrol, and LPG, but they are more on the RV8, but you can only ask. Be careful however, they are a bit too inclined to sell there own praises!

Edited by blitzracing on Friday 10th June 20:30

[100SRV]

Cheers Blitz, I think that is the cause of the problem...I have wondered about a home-brew ignition driver with built-in knock detector controlled by a PIC for just this purpose...run up to knock point then back off by 3 degrees and hopefully all is well.

[Steve_D]

100SRV said:

Cheers Blitz, I think that is the cause of the problem...I have wondered about a home-brew ignition driver with built-in knock detector controlled by a PIC for just this purpose...run up to knock point then back off by 3 degrees and hopefully all is well.

Your problem will be finding a system which can truely detect knock. It took mainstream manufacturers many years to get it right with a good deal more resource than we can throw at it.

Steve

[anonymous-user]

100SRV said:

Cheers Blitz, I think that is the cause of the problem...I have wondered about a home-brew ignition driver with built-in knock detector controlled by a PIC for just this purpose...run up to knock point then back off by 3 degrees and hopefully all is well.

For those that know their onions:

http://focus.ti.com/docs/prod/folders/print/tpic81...


(if you have no idea what all that means, i suggest you stay away from DIY KCS..... ;-)


Also, remember, that the engine doesn't knock across all speed and load points, hence you always need a base map to start from.

[dnb]

I like the plan, but suspect that by the time you have got a workable solution you could have got close to buying a 2nd hand ECU to control the timing.

You may find the engine will get to minimum best timing in a lot of the operating range (LPG has a high octane rating IIRC) making a knock sensor totally useless - by the time you get knock through advancing the ignition you are already well past peak power.

[blitzracing]

http://cgi.ebay.co.uk/Dual-Timing-A-R-Amp-Ignition...


I bench tested the previous version, just to measure the HT voltages and dwell periods versus the Lucas ignition amp, and it performed well enough, but no where near the 50 kv the talked about (that's a completely irrelevant figure any way considering the plug fires at about 10-20KV) and the stock coil simply wont go that high even open circuit. It had a slightly lower HT voltage than the Lucas unit at higher RPM, but a longer burn time (and shorter dwell). It was switchable between points and the inductive pick up. I did not look at the LPG side of the timing, but I think its what you need.