zoltan Posted January 12, 2012 Share Posted January 12, 2012 Not entirely Land Rover so that's the OT disclaimer out of the way. Anyone using a Bigas M84 vapouriser on their RV8? Ive just fitted one on my Russian Gaz66 truck (which is a super lazy 4.2 V8) but I'm having difficulty getting AFR down to even 15:1 on idle. I'm probably missing something obvious but wondered if the M84 really does run engines upto 190 bhp or if people have found that is way too optimistic Engine spec ZMZ 4.2 litre pushrod V8, 2 valves per cylinder, about 7:1 compression, very short cam duration and quite low lift to suit 76 octane Russian fuel. I'm using a BLOS propane carb which runs fine on my 3.5 V8, no shortage of gas there, sits at 14-15 AFR throughout the map. Im running a MS1 V3 ECU with EDIS. The inlet tract is fairly free of restriction, through the BLOS carb, through a single throttle body from a Volvo V70 onto a home made manifold onto the Russian inlet manifold There is gas in the tank, plenty of it and the all new pipework runs through a brand new filter solenoid before it sees the M84 vapouriser This engine makes 115bhp in standard tune so its no rocket ship but accepting it's big lazy size, it would normally do about 10mpg in standard tune on petrol, could I be right at the limit for the M84? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 12, 2012 Share Posted January 12, 2012 You should be able to get it to the right AFR at idle at least, a too small vapouriser would normally only show once on the gas, where gas requirement is maximised. What is the limit of the BLOS? I seem to remember 2 being recommended foranything over a RV8 3.5...? Quote Link to comment Share on other sites More sharing options...
zoltan Posted January 12, 2012 Author Share Posted January 12, 2012 I don't know anyone running just one on anything over a 3.5 now you mention it. It isn't something I should overlook. It maybe as simple as widening he V shaped slot in the tube if the BLOS is the problem, I recall there being different tubes available. I've got the idle adjuster almost falling out on the M84 so something isn't right. I thought at first I had run out of gas but I remember putting about 60-80 litres in last year (140l tank) so unless it has all leaked out, the truck hasn't been anywhere yet. I tried to get some in today and it was pretty much full. There is no level indicator on this tank (single hole) which doesn't help. Not that they're much use. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 12, 2012 Share Posted January 12, 2012 You are correct about the slot options in the BLOS, though I had forgotten about it until you reminded me I assume you have adjusted the BLOS as well? Good PDF on it here: http://www.corrado.com.pl/warsztat/blos/blos_evolution_ml.pdf Quote Link to comment Share on other sites More sharing options...
zoltan Posted January 12, 2012 Author Share Posted January 12, 2012 Yes, I've wound the main slotted tube right down and the idle adjust all the way so it might just be a matter of the tube itself. Given that the engine is so woefully inefficient it might well need 200bhp's worth of fuel to do its 115bhp output. The tube is pretty simple, I will make another one to test the theory. I don't want to have to go with a mixer if I can help it, the BLOS doesn't impede the airflow at all by comparison. Fitting two of them would involve even more plumbing headache Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 12, 2012 Share Posted January 12, 2012 Could well be right about the efficiency mucking it up, good luck with it Quote Link to comment Share on other sites More sharing options...
Quagmire Posted January 15, 2012 Share Posted January 15, 2012 We have three m84s running my dads 101, the 110 and my 90. I have never had problems getting mixture rich enough, usually quite the opposite! Quote Link to comment Share on other sites More sharing options...
zoltan Posted January 15, 2012 Author Share Posted January 15, 2012 Thanks, I need to be looking elsewhere: the BLOS carb and it's slot. I took the tube out of the carb and feel the V shaped slot needs to be larger. At present the slot is about 45mm long tapering from about 9-10mm to nothing. Rather than ruining the tube I have I will make another larger tube and see how that fares. I expect you can get spares, I know they do a Type D but by the time Ive tracked one down I can have one made. Quote Link to comment Share on other sites More sharing options...
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