clubstylus

In my opinion the V8 is a fun day rocket but not really an everyday car. It could be if it was converted to LPG or possibly injection, but it would be expensive to run otherwise(i'm probably getting about 25mpg with 4 barrel holley).

madmaninshed wrote:In my opinion the V8 is a fun day rocket but not really an everyday car. It could be if it was converted to LPG or possibly injection, but it would be expensive to run otherwise(i'm probably getting about 25mpg with 4 barrel holley).

The only problem with LPG is you have to fit the tank somewhere,which means limited boot space,then theres the extra weight to consider, and im pretty sure the engine runs hotter.


Phil...

madmaninshed wrote:In my opinion the V8 is a fun day rocket but not really an everyday car. It could be if it was converted to LPG or possibly injection, but it would be expensive to run otherwise(i'm probably getting about 25mpg with 4 barrel holley).

Yeah, my 4 barrel weber gets about 25mpg too on a run. The problem for me is not so much the cost of fuel (since I don't do that many miles), but more the limited range that one 6 gallon tankfull gets!

LPG wouldn't be so bad if you could remove the petrol tank entirely, and run purely on LPG. Don't know if this is possible though.

I'd prefer carbs to injection any day on an RV8, since it fits under the bonnet, and carbs 'just work'. No dodgy electrics and ECUs to worry about! A good four barrel will give just as much power as injection anyway. Makes nice slurpy sounds too!

Jeff

I believe my tank is 9 gals, so get a reasonable range. Regarding LPG only...I did some research and the only reason for having both fuels apart from the convenience of finding petrol stations rather than LPG is freezing up when the engine is cold. Once the inlet manifold is warm, there is no problem. Some cars will start on LPG and dont suffer from this. The problem with running both fuels on older systems is that LPG requires a different map due to slower and hotter combustion. If you set it up for petrol, it won't run properly on Gas (or visa versa). The latest (mainly Italian) systems have injectors for each cylinder and can have dual maps - one for petrol and one for LPG. This is an expensive conversion, but does it properly. Gas is actually a higher octane fuel and set up properly with the timing altered, you should lose no performance. I'm not totally convinced about the cost savings though. They say you use 20% more LPG than Petrol, but petrol is about double the price of LPG, so you should save about 40%.....could someone be a little biased? There have been reports that some RV8's are unsuitable for LPG. Some of the larger engines with thinner liners can suffer due to the increased heat of combustion. One of the best features of LPG is no emissions, and even the engine oil stays clean - lovely and golden.

madmaninshed wrote: The problem with running both fuels on older systems is that LPG requires a different map due to slower and hotter combustion. If you set it up for petrol, it won't run properly on Gas (or visa versa). The latest (mainly Italian) systems have injectors for each cylinder and can have dual maps - one for petrol and one for LPG. This is an expensive conversion, but does it properly.

Mine runs a megasquirt for sparks only (MSnS-extra), so switching between two ignition tables at the flick of a switch would be no problem! I'm tempted to do it just for 95 and 97ron petrol.

I think I've seen some LPG mixers that fit on the top of a four barrel carb flange and sit inside the air filter? Anyone heard about these? Are they any good?

Jeff

I've heard of them. Think Rimmer Bros have an expert - certainly one of the RV8 parts and engine suppliers does.

There was an article in PPC a few months ago about the use of LPG and one of the points it made was that LPG really needs a lower compression ratio and if you can reduce the ratio then LPG is actually as efficient as petrol.