The V8 Owners Forum -

All together I paid 2 separate company's a total of £900 for Mapping
Not Happy

I had a low end shunt on mine which we could not cure
Dale at Bailey sorted mine out and it drove like a dream after that

Coops wrote:I had a low end shunt on mine which we could not cure
Dale at Bailey sorted mine out and it drove like a dream after that

I worked on many troubles that look crazy and there seems no remedy.
With no doubt it takes time for fully understanding the complex data
you get from a MS log.

But with no doubt these log informations contain much more data, especially
what makes the MegaSquirt react as it does. So with these informations and
good skill the results must be better than only watching dyno and AFR.

So its very pleasant to fiddle out a nasty problem by yourself and gives
some nice progress in knowledge. It only needs time and patience (and MS).

Low end shunting can often be masked by dialing out ign advance and richening thing up a little on the RV8 running a plenum, when off cam mine only behaves at around 12.5 AFR below 2200rpm so have set the WB closed loop target values at that which works quite nicely, open loop was not an option for me in this zone because when temp conditions changed so did the AFR and hence the lurching I really am on that ragged edge of driveable and bloody horrible and the richer mixture is the only thing that keeps things in check, idle no issues I run that open loop at around 13.5/14 all self inflicted of course I am running a mech 238 cam it does behave better than I expected and is surprisingly punchy midrange but revs likes a mad thing

I'd guess a lot of these problems are due to using Alpha-N rather than Fuel Density?

Yes, Alpha-n is a pain and should only be used when cam does not
allow speed density.

Around idle the mapping can be made quite fine and fiddeling with
the y-axis is worth to spend a day on it.

I was very astonished that with speed density under full load
some pulsations at some revs spoiled the fuelling.

Seems that MS sees significant manifold pressure and leans mixture.
I had to swap to blended Alpha-n/SpeedDensity because I could not
get rid of that problem.

..... all a good job for the Megalog Viewer.

DaveEFI wrote:I'd guess a lot of these problems are due to using Alpha-N rather than Fuel Density?

I run speed density as I know the benefits and glad my new motor spec just about props this up because my vac signal at low speed is piss poor but I am glad I stuck with it I have an inline filter and smallish Weber fuel jet in the MAP line to keep things smooth and less noisy once over 2k its all business as usual, I did give hybrid Alpha N a go but it all seems additive and my fuel map was already there and it felt like I would have to start my VE table from scratch pretty much Alpha N does seem more tolerant to the RV8 using a plenum and big cam at low speed though as in less kangarooing/lurching I will stick with S/D for now though my tune is pretty good

A long shot I know.
Has anyone using the TA/TRS heads have a template for cutting the valley gasket please before I bugger up my new gasket trying to work it out.

Mine is off at the moment so could trace round it. Not so much a gasket as an ally cover plate.
Where did you get your heads from?

mark

That would be great if you could please mate,
mine came direct from TA,
no gasket listed have to cut your own,
so going to use either a tin one or a composite one cut to suit,

how thick is the ally out of interest??

If you can find anyone with a large scanner, scan it? Put that file in a CAD prog and draw it out?

That's basically how I copy PCBs.

Mine came with the heads pre cut. I had to do a small amount of fettling.
it looks to be about 2mm thick and has been rolled to give it the same curve as the block. I don't think cutting down a comp or tin gasket would work. give me a couple of days and I will trace round it.

mark

Thanks Mark

Coops have drawn round my valley cover plate. pm your address and I will send it. Needs to be cut out of ally plate and rolled to shape.

mark

PM sent Mark,
thank you for your help