The V8 Owners Forum -

..... it's been a long time coming but I'm one step closer to getting on the road - I trailered my Westfield to a rolling road yesterday.

314.8 BHP @6100rpm
320 FT/LB @4500rpm

from my RV8 4.2ltr (+.020), MC1 cam, 10.2:1 CR, Stage III heads, ported hotwire manifolds, ACT carbon plenum, 4.6 throttle body, MegaSquirt 2.

Needless to say I am well chuffed from an engine I built with limited knowledge. So a big thanks to everyone who answered any of my dumb questions.

Only pain was my lambda sensor gave up so it's been mapped without it.

IVA test next ! IT's a '92 block so I with 90ppm HC and 1 ish %CO it should be fine

Mike :):)

Yep your emissions should be good - good luck!

where did you go mate?

Hi Coops,
I took it to http://www.dyno-tech.co.uk which isn't too far from me.
I'll get the map and plots uploaded later if anyone's interested.
Mike

Yep,post them up

Quick question, why do your fuel and ignition load percentages not start at zero?

I have a question as well. Why did they use 3rd gear as I am led to believe that would have a positive effect on the results according to Dave Walker.

He has always done my runs in 4th eg 1-1

r2d2hp wrote:I have a question as well. Why did they use 3rd gear as I am led to believe that would have a positive effect on the results according to Dave Walker.

He has always done my runs in 4th eg 1-1

That's interesting. Someone would have to explain the physics to me! 1:1 in the gearbox then you still have the diff ratio and tyre size determining your road speed.

A quick bit of googling seems to suggest there's all sorts of opinions. One guy on pistonheads seemed to get better figures in 4th.



Mike

Dave Walkers site is quite informative and based on his experience over the past 30 years http://www.emeraldm3d.com/rolling-road.

Section "BHP at your wheels" discusses why BHP goes up when a lower gear is used

Cobratone wrote:Quick question, why do your fuel and ignition load percentages not start at zero?

I have no idea

I'm using speed density for both fuel and ignition if that helps.

Mike

seight wrote:

Cobratone wrote:Quick question, why do your fuel and ignition load percentages not start at zero?

I have no idea

I'm using speed density for both fuel and ignition if that helps.

Mike

I use speed density too and my tables start at zero which is where the car idles at as there is no load on the engine. All my cruise and the majority of my driving is done with a load less than 15% so not sure why yours would start there, unless I have it wrong??? Anyone else got an opinion??

*addition* I'm actually running AlphaN, not speed density which explains why I was confused. Sorry

I dunno Tone.
My understanding was that speed density is about manifold air pressure etc and even at idle you'll have something. If you use TPS position then you would have a zero. But I may be talking carp.
Mike

seight wrote:I dunno Tone.
My understanding was that speed density is about manifold air pressure etc and even at idle you'll have something. If you use TPS position then you would have a zero. But I may be talking carp.
Mike

That explains everything Mike, I'm talking out my arse I run AlphaN (TPS) not speed density! My mistake, sorry for the confusion

r2d2hp wrote:Dave Walkers site is quite informative and based on his experience over the past 30 years http://www.emeraldm3d.com/rolling-road.

Section "BHP at your wheels" discusses why BHP goes up when a lower gear is used

Interesting read but it also suggests losses are greater at higher speeds so although you get a lower wheel bhp you add on more for transmission losses in order to guesstimate flywheel bhp.

If you do the run in a lower gear and lower speed you add less on.

I'm going to spend hours reading this stuff now you've started

Mike