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[JamesV6CDX]

Any 3.2 LPG owners, please would you be good enough to give me the following info?

Gas Pressure:
Injector Type:
Injector Size:
Any lag:

I am really struggling to get my 3.2 'quite right' on LPG. My nozzles were always 3.0mm and at a pressure of 1.4 bar it wasn't too bad but gave a good jolt changing gear at high revs.

After reading lots of posts about the vaktek red 3ohm jobbies (like mine) not really being quick enough to power a 3.2 at full chat, I took the injector sizes out to 3.5mm (as far as I dared) in hope of overcoming this.

I think this may have been a mistake.

Upon calibration with the new size, the start of the multiplier line went a lot higher - around 1.6. The Jolt was just as bad, if not worse.

I tried reducing pressure to 1.1bar, calibrate again - same issue. Jolt.

The mapping is OK, I can get the lines to pretty much overlay each other.

If you leave the transmission in second, and boot it, it will go right up to the redline without giving the "injectors fully open" warning, it's only when changing into third, the jolt occurs just afterwards.

Also - if you move the multiplier down quite significantly, it drives perfect all through the rev range, with no jolt, BUT it flags a fuel trim code, so that fuelling, while it removes the jolt, obviously isn't right.

I am starting to believe I won't get anywhere with these old style valtek injectors and should probably just upgrade to some faster ones, that don't require such a large nozzle size? 

Ideas welcome - mucho thanks

[feeutfo]

Depends what vap fitted too. The dual exit ones in conjunction with grey valtek injectors run 2.2/2.3 mill nozel jet size. No lag.

Way smaller jets than the single outlet black vap of the older kits with red injectors. I never got rid of the lag on my old 3.2 kit, with upright single hole tank.


Should add there is some lag on lift off at high rpm over run on petrol only as stock.


Both set ups run 1.1 bar.

[JamesV6CDX]

Cheers Chris, that's appreciated.

I have a KME Gold dual output Vap, so thinking I may just upgrade to the grey Valteks.

Is Teilo still the best source?

[Kevin Wood]

My opinion is that it's the Valtek injectors. They have a slow open/close time so cannot keep up with an engine doing 5000 RPM+. You can chase your tail trying different pressure, nozzle size, etc. but I don't think the issue will go away. If it bothers you that much, set it to flip to petrol at the speed of your choice and ignore it.

The grey injectors flow much more gas at a given vapour pressure and nozzle size than the red Valteks. I don't know whether they are faster opening/closing as I haven't seen any specs for them; it could be that the increased flow rate gets them out of trouble, and they are just as sluggish. Having said that, they are more tricky to set up to achieve a decent idle as a result, because below about 3ms you can't get any reduction in fuelling, so if the ECU tries to dip the injector duration below 3ms due to the lambda loop, the engine will bog down and then surge. You have to be careful sizing the nozzles to get a decent idle.

The vapouriser? Probably a red herring IMHO. IIRC I saw an install with the new style vap and red injectors, or was it the old vap. and greys? Can't remember whose it was, but the problem stayed with the injectors.

[Kevin Wood]

I have a KME Gold dual output Vap, so thinking I may just upgrade to the grey Valteks.

There you go.. it's the injectors.

Would be interested in the cost of them myself, although mine isn't really too bad. If they are cheapish I might be tempted to swap.

[feeutfo]

Your welcome to swap with mine to test if you want to prove it thoroughly first?

[JamesV6CDX]

Magic Jet £100 a set

(Mr Sassanach has had much sucess with these on his big motors, despite some poor industry reviews) - they were also brilliant on my old 2.5.

Valtek Type 34 - £140 a set.

[JamesV6CDX]

Your welcome to swap with mine to test if you want to prove it thoroughly first?

If you guys do go ahead with this, please keep us updated as to the result

[sassanach]

magic jet... wonderfull, have yet to see anything beat them for the price,as for valtek's...well they are just about acceptable on my range rover, but only just!!

[JamesV6CDX]

If ever you decide to advsertise that RR mr S, please let me know I rather liked the look of it!

[sassanach]

if i recall correctly i think the size of the hole in the nozzles(in the manifold)is only 3.0mm anyway so drilling the injector end beyond 3.0mm is a waste of effort.

[JamesV6CDX]

if i recall correctly i think the size of the hole in the nozzles(in the manifold)is only 3.0mm anyway so drilling the injector end beyond 3.0mm is a waste of effort.

Thanks for that info

[tigers_gonads]

Is this a problem with just auto boxes or with manual too ?

[Kevin Wood]

if i recall correctly i think the size of the hole in the nozzles(in the manifold)is only 3.0mm anyway so drilling the injector end beyond 3.0mm is a waste of effort.

Yep, I think you are right. In addition, I think above 3mm you will be weakening the nozzles too.

IIRC, the grey injectors are made by AC?

[TheBoy]

The KME and grey injectors do not cause lag on 3.2 Omegas, unlike the high rpm gearchange problems I've never managed to fully overcome on the 3.0 that has red valteks