help needed

K4000JB · Post by **K4000JB** » Sat Nov 03, 2012 1:13 pm

Hello can anyone help I need to find out where peak power occurs on a rover v8 when fitted with a 256 camshaft just as a guide for me to start mapping
Thank you in advance

kiwicar · Post by **kiwicar** » Mon Nov 05, 2012 10:18 am

Hi
A little more information would help unless you want a +/-1500 rpm figure. . .
Do you have the timing specs for the cam? like the duration at 50 thou (or am I meant to find that for you?

) some idea of heads, capacity carburation would help also.
For a first punt if it is a 3.5l then 4500+/- 1500 revs if it is 4.6l then 3800+/-1500.
Best regards
Mike

DEVONMAN · Post by **DEVONMAN** » Mon Nov 05, 2012 12:23 pm

When I have done some initial mapping I used the Torque Graph/Curve of the engine/cam to get the peak fueling point and not the Horse power curve.

I believe I'm correct in saying that max fuel requirments coincides usually with max torque.
( I will wait to be shot down in flames)

Regards Denis

kiwicar · Post by **kiwicar** » Mon Nov 05, 2012 3:51 pm

Hi Denis
peak fuel requirments vary very much from engine to engine, richest mixture generally is required at peak torque, on most engines anyway, and maximum volumetric efficiency 99% of the time coincides with peak torque (lots of cylinders and ancilleries can effect this).
On a small block chevy running N/A on methanol and mechanical injection it quite often the case that no more fuel is added after peak torque, this is because of rapidly falling volumetric efficiency, and that the engine likes a leaner mixture for peak power, other engines, like the A series likes a rich mixture at high revs otherwise they tend to have high speed detonation.
No flames, but also not any general rule I know of

Best regards
Mike

mgbv8 · Post by **mgbv8** » Mon Nov 05, 2012 10:02 pm

DEVONMAN wrote:When I have done some initial mapping I used the Torque Graph/Curve of the engine/cam to get the peak fueling point and not the Horse power curve.

I believe I'm correct in saying that max fuel requirments coincides usually with max torque.
( I will wait to be shot down in flames)

Regards Denis

You wont get shot down by me Den!!

On all my engines from 3500 to 4600 with real steel typhoon and blower cams I've made peak torque around 3000 rpm with bags of fuel.

But then my engines are 1/4 mile only. On nitrous the peak torque drops into the 2700 rpm zone. So i adjust this by tweaking cam timing a bit.

K4!
What size engine do you have and what other mods have you done??

Perry