Rover KV6 flat below 5000 rpm

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Auntyval
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Posts: 17
Joined: Wed Sep 12, 2012 10:52 am

Rover KV6 flat below 5000 rpm

Post by Auntyval »

Hi,

I have an MS2 V3 running Alpha - N on a KV6 in a off-road competition Land Rover. It has throttle bodies and a tuned exhaust and drives through an auto box converted to paddles. The MS was originally built and installed "professionally" , although I have spent a long time correcting sensor earth faults etc. It seems to run reliably now and the VE and ignition maps have been set professionally on a rolling road. the power curve is a straight line from 60BHP at about 2250 rpm to 135 at about 4500, then level after that. 135 sounds a bit low, but this is only an estimate because of the unusual transmission.

The problem is that it that it doesn't pull and seems flat below around 5000rpm after which it takes off and pulls well, but runs out of revs at 7500. I need more flexibility to get it pulling at lower revs. A mate with a similar vehicle assures me that his pulls well from much lower revs.

Because it's not on the road, I don't have an up to date datalog. I hope someone can make sense of it from the MSQ.

Thanks for your help

John
DaveEFI
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Re: Rover KV6 flat below 5000 rpm

Post by DaveEFI »

Interesting choice of engine - must be near unique in a Land Rover. :D Most use the RV8. For which you'd find a wealth of data for MS.

A quick glance at the VE table suggests your tuner has only worked on maximum power.

Generally, a VE table starts out low in the bottom left corner, and goes up in all directions from that. Yours appears to have random cells which don't follow that.

Have you got a wideband O2 installed, so you can see an AFR readout in the problem areas? Tuning without one is near impossible.
Rover SD1 3.5 EFI
MS2 V3
EDIS
Tech Edge O2
London UK.
Auntyval
MS/Extra Newbie
Posts: 17
Joined: Wed Sep 12, 2012 10:52 am

Re: Rover KV6 flat below 5000 rpm

Post by Auntyval »

Thanks Dave, yes, it is unusual, especially with the paddle shift. With the front wheel drive gearbox it is a lot lighter than a V8 with land rover box and should be about the same power as some of them. I don't do too bad, came 3rd in the ARLC annual national rally comp safari. It does sound great at full revs compared to all of the plodding V8s.

Although this wasn't discussed with the tuners , TBH, so long as it runs smoothly I am not too bothered so long as full throttle does its job. The problem is that it doesn't seem to, with a real lack of power below 4500 and a question over the power level above that.

I do have a wideband sensor and have previously tried autotune without much success. With it not registered for the road it is difficult to find a good stretch to do any tuning which is why I went to a rolling road. They also questioned if the sensor was working properly !

I am still not convinced that the main setup is OK, are 6 squirts good ? should it be running without crank sensor filtering etc. I have no confidence that the original tuner was any good, but I am not sure what needs changing in the basic setup.

I will try to get some short runs this weekend.

Thanks again

John
DaveEFI
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Re: Rover KV6 flat below 5000 rpm

Post by DaveEFI »

I'm not familiar with tuning throttle bodies and alpha-N, but I'd be inclined to check the basics very carefully. Is your req_fuel and injector dead time correct? Make sure your injector flow rate is calculated for the actual maximum fuel pressure you are running at. Google for dead time, or work it out yourself. Then use the tool to generate a VE table, and compare to yours. (you will need to know the output of your engine) If the cells on the new table are very close to the old one where it was obviously tuned on the rolling road, I'd use that as a starting point, but obviously keep your original tune. Not sure about squirts per cycle with TBs.

Dunno how you get round not being able to tune on a road, though. I'll usually spend a half day or so on a quiet road trying to cover all engine speeds and load.

VEAL here usually works very well, which makes me wonder about your basics.
Rover SD1 3.5 EFI
MS2 V3
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Tech Edge O2
London UK.
Auntyval
MS/Extra Newbie
Posts: 17
Joined: Wed Sep 12, 2012 10:52 am

Re: Rover KV6 flat below 5000 rpm

Post by Auntyval »

Hi all,

Thankyou for your help, I have now modified the exhaust and got it running much better, but I am still confused by the log.

The EAE is turned off, but still shows a value of up to 100% in the log which does seem to be making a difference and making it run very rich.

Is this correct ? and is there a simple way of getting round it ?

I will be taking it to the rolling road soon, but want to get everything right first.

The msl shows several accelerations in first and second gear

Your help would be appreciated

Thanks

John
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