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Wales
by Joske Vermeule, September 1
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Jun 14th, 2026
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Joined: Aug 2015
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Talk Morgan Enthusiast
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OP
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Maybe a silly question but here goes. My GDi Plus 4 rev counter goes up to 9000 rpm - and there's no red line. Now it's run-in, and when fully warmed up, there seems to be plenty of oomph up to at least 7000 revs; which is where I've stopped, which, in the absence of further advice, seemed like a reasonable stopping point.
So, is there anything to be gained by going higher than that and is there a 'virtual' red line at which I should really stop? Does the GDi do a 'diesel' and abruptly stop producing power at some point? Should I do it all by 'feel' and ignore the rev counter? Or does anyone have any other advice or opinion?
Last edited by Fox Terrier; 02/01/16 04:18 PM. Reason: missed apostrophe
Morgan Plus 4
Royal Enfield Classic 350
Brompton M6L
Giant TCX Advanced
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Joined: Dec 2008
Posts: 22,370 Likes: 354
Roadster Guru Member of the Inner Circle
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Roadster Guru Member of the Inner Circle
Joined: Dec 2008
Posts: 22,370 Likes: 354 |
I would expect there to be a rev limiter. I found it on my V6 couple of times, but didn't have time to look down to see where it was.
DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4
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Joined: Feb 2012
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Charter Member
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Charter Member
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Most modern cars have a built in electronic limiter.
Martin (Deano)
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Joined: Jan 2011
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Charter Member
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Charter Member
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Definitely not a silly question and which I have been pondering for a little while. In the course of "normal driving" (no such thing in a Moggie) I rarely go above 4000rpm, the GDI engine seems to provide enough poke at that level and I seem to recall that the handbook quotes somewhere around 6000rpm for max torque so I would also be very interested if anyone who has real knowledge can enlighten us. 
Here for a good time not a long time!!
Reg
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Scruffy Oik Member of the Inner Circle
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Scruffy Oik Member of the Inner Circle
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Modern ECUs implement a two-stage rev-limiter, an initial 'soft cut' followed a couple of hundred rpm later by a 'hard cut'. These just cut some or all of the ignition pulses to reduce the revs (or prevent them from rising any higher). On my engine, and also I believe on the 2l Duratec, the soft cut is set at 7000 and the hard at 7200 IIRC.
I would think the GDi rev limit would be around the same, so revving to 7k would be fine, much better to let an engine spin up in lower gears than make it pull a higher gear than it wants to.
Tim H.
1986 4/4 VVTi Sport, 2002 LR Defender, 2022 Mini Cooper SE
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Joined: Aug 2014
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Charter Member
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Charter Member
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Maybe a silly question but here goes. My GDi Plus 4 rev counter goes up to 9000 rpm - and there's no red line. Now it's run-in, and when fully warmed up, there seems to be plenty of oomph up to at least 7000 revs; which is where I've stopped, which, in the absence of further advice, seemed like a reasonable stopping point.
So, is there anything to be gained by going higher than that and is there a 'virtual' red line at which I should really stop? Does the GDi do a 'diesel' and abruptly stop producing power at some point? Should I do it all by 'feel' and ignore the rev counter? Or does anyone have any other advice or opinion? If you put your Mog on a rolling road to set it up you will get a data sheet with the peak power , that's where you can rev to a sensible Max !
Geneva 2016 plus 8' The Green Godess' 4 side exits .
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Joined: Jun 2014
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Talk Morgan Regular
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Talk Morgan Regular
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We all know supposedly similar Morgan's are often quite different but if it helps this is what my GDI does.
Revs very nicely up to about 6800 when the electric limiter/ fuel supply cut off kicks in. At 6500 a red light appears in the rev counter as a warning to change up.
I also have a before and after dyno chart, my car was the development car for the Librands exhaust manifold and cat, and that too shows the engine won't rev beyond 6800 with the power dropping off before then.
None of my Morgan's have had a red line so that's probably quite normal.
Andrew
'Alice' 2013 Duratec Plus 4. Pearl Blue
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Haven't seen that red light. I'll have to have a look when it stops raining!
Morgan Plus 4
Royal Enfield Classic 350
Brompton M6L
Giant TCX Advanced
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Talk Morgan Regular
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Talk Morgan Regular
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There's a few warning lights built into the instruments but I can't tell they ere there unless they are illuminated. The other light that surprised me the first time it came on was the orange low fuel light in the fuel gauge that comes on when there is about 10 litres left.
Andrew
'Alice' 2013 Duratec Plus 4. Pearl Blue
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Member of the Inner Circle
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Member of the Inner Circle
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Normally the limiter would not be a fuel cutoff as that would be quite dangerous for a motor on the limit as you would suddenly get a very lean mixture with the possibility of burning valves and holes in pistons and such. Paticularly a problem if you were going downhill. I believe the normal prceedure is to drop the timing to full retard which has the efect of dropping the power significantly but still keeps the input of fuel to stop overheating.
Peter ![[Linked Image]](http://bradley.it/public_images/drive.jpg)
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