Rover V8 firing order

[350matt]

Wotcha
I don't know if anybody on here keeps up with Chevy tuning, but a recent tuning mod for the small block boys has been to change the firing order, swapping cylinder 4 and 7. The point of comparison is that the Small block has the same firing order (1,8,4,3,6,5,7,2) as the rover. So concievably this would work for this engine too.
Anybody heard anything else about this?

Matt

[GreenV8S]

Haven't heared about this (but I'll ask around). What is the reasoning behind it? From the breathing point of view it seems to me you still end up with conflict between 7/3 and 4/2 (rather than 8/4 and 5/7 with the conventional firing order). Is there some benefit I'm overlooking?

[350matt]

I think that providing the intake manifold has a common plenum then you might well get the relected pulse from the closed valve in 8 then rushing across into 7 (bear in mind the Yanks odd numbering method - odd cylinders on LH bank even on right with no. 1 at the front and LH is drivers LH)
Just wondering if anyone had heard of anything similar in rover-land

Matt

[deltaf]

Firing order on the Indycar V8's was changed something like this iirc.
Only they had 2 cylinders firing at the same time.
Sounded weird from what i remember.
Details anyone? Or have i lost contact with mission control yet again?

[steve_D]

When I did the research for building my Chevy engine this change was mentioned.
It is claimed to provide a better gas flow as the pulses are more evenly distributed.
The guys over the pond have been playing with these engines for a very long time so if it had real benefits then they would all be doing it.

Nice idea but I doubt the benefits outweigh the costs.

Steve

[350matt]

Well I think its a fairly new idea for them, details are on the Compcams website so its probably just starting to take off. Also the additional costs are only a camshaft, you don't need a new crank so if it worked the customer just has to pay for a billet cam as opposed to one ground from a blank.

Matt

[350matt]

well I suppose the next question is how much is a billet ground cam?
If no-one else will have a go that is.....

Matt

[stevieturbo]

Realistically, what sort of gains are you talking about ??