Rev limit 4.0ltr?

[dings]

Hi all, I have a 4ltr Chim and had a good dust up last night for the first time, I noticed when it gets to 5000rpm it seems to have a little misfire or is holding back slightly any ideas or advice to get it to stop this little niggle, cheers

[Pupp]

Some of them do seem to have lowish rev limits and, in practice, it's not usually a problem as the power/torque will be well dropping off unless you've done some mods to cam/induction etc. Change gear earlier, much earlier... you'll go way quicker Mine started off as a serp 400 and I'm pretty sure it was happy enough up to a shown 5,500 but then brick-walled. Rev counters are not always that reliable either.

There is scope to rev out the motor more ... 6,200 seems to be an accepted limit when mapping new fuel chips and the later cars seem mechanically ok up to that but I doubt there's any real benefit to screwing the last few revs as on most road driveable set-ups the power drop off is pretty dramatic and you're only really making noise/increasing stress beyond what you actually need to.

[JonathanT]

my '99 Chim 450 has the rev limiter (factory) set to 6250rpm.

[blitzracing]

The rev limiter is part of the fuel map chip on the ecu. Limits as low as 5200 - 5400 rpm are part of the origional Land Rover / Range Rover mapping. After market chips can be a lot higher.

[Chassis 33]

The revlimiter in the hotwire ECU is like hitting a brick wall, not "holding back", and 5000rpm is very low. Iffy HT leads can cause this missing/holding back at high revs, it was a problem on the racer for a while, however fueling issues (tired fuel pressure regulator) can also cause this.

Check condition of HT leads and check fuel rail pressure (if you don't have a suitable gauge most garages will).

Regards
Iain

[dings]

Cheers lads,

I am going to order new leads, diz cap, rotor arm, everyone says to use magnecor also Castle Race's own which one would you recomend,

Cheers

Neil.

[Chassis 33]

My preference would be to get them from Jamie at CRE, but everyone has their own favourite flavour.

Regards
Iain

[jj.]

My '96 4l - pulls with eager all the way through to it's 5800rpm cut-out limit, (as indicated on the rev gauge) - how accurate the rev gauge is is a different matter, if it's like the speedo - phew!.
jj

[trackcar]

CRE's leads are top notch

Agre with chassis33 .. fuel regulators can cause weak fuelling which can give you the symptoms you're experiencing. My own 4 litre went from 130hp to 198hp just by replacing the regulator!

[Rum Runner]

My 4.0HC went to 6250 before it hit the limiter which was easy done as the engine was so rev-tastic and very sweet sounding .500 is some how easier to gauge the revs , probably due to longer stroke .