scotthunter

Max Cruising Rpm For A Metal?

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Hello,

I'm a Fiesta Metal owner. I've been the owner of this car for around 18 months now and love it. One thing that is very noticeable is the short ratio gearbox, and without a 6th gear the engine does have to work hard to cruise above 80/90mph on the motorway. At 100mph the engine speed is around 5000rpm (1000 below the red line). So, while the punchy little 1.6 engine and close ratio gearing makes this car good fun for driving around town and along country lanes, this car was never intended to be a good motorway cruiser.

My question is, legality and fuel economy issues aside, will keeping the revs at 5,000rpm in 5th gear for extended periods of time damage the engine in any way? The car gets a regular service at Ford, so always has good oil inside, and I always make sure the engine is warmed up before I explore the upper reaches of the rev range (which is only occasionally).

Scott

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it's designed to do it so yes, where some people raise the limiters via mapping, no that isn't safe and hence why void under warranty, Ford will run them in at about 5999RPM for a while before it leaves the factory.

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it's designed to do it so yes, where some people raise the limiters via mapping, no that isn't safe and hence why void under warranty, Ford will run them in at about 5999RPM for a while before it leaves the factory.

Very much doubt they'll take the engine to it's max rpm's during the production processes, they'll put the car on a rolling road and take it through various drive cycle and braking tests plus some running on a short test track like a 'Belgian Road' for squeak & rattle evaluation but there won't be any running in done.

Doing that would add time (and cost) to the build processes plus maybe need more fuel adding at the initial fill. You'd be surprised at the scrutiny they apply to extra costs - an oncost of even just £1 per car has to go to very high level before getting approval.

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They actually do run them in like that, why pay people to drive them around ( would need to employ tons of people think about it ) or just hook it up to a Cpu and redline it for a while, if successful the car is good to go, best way and most cost and time efficient, most manufactures do it.

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If your worried just keep it to 70 :P

I usually cruise at 70 or even 60 because this car has crap fuel economy on the motorway (the engine speed is 3300rpm at 70!) but on the odd occasion when I need to put my foot down, I'm always paranoid that I'm putting too much strain on the engine, having the engine speed so high for extended periods. I'm guessing this isn't an issue in the ST because it has a 6th gear...

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6th Gear on the ST is actually quite short, but don't worry about the wear issue, RS Clios generally sit at around 4K at 70MPH and they don't actually provide any power until the VVT kicks in at 5K, they love being reved to the limits.

It'll be fine, in the manual it'll probably tell you ( they currently do with the 7.5 ) what the optimum cruising speeds are per gear, the new ST is something stupid like 43MPH to achieve max economy ( 58MPG at this speed according to the trip cpu )

Only issues that really pop up on NA engines at speed is the belt snapping, if it's been changed then fine, dropping a valve, another service issue., Low oil pressure again service related, anything is just random unlucky stuff.

It's far better imo to keep it going at speed than constant blasting off the lights and stopping and repeating.

It'll be fine, and put it this way, given what market that and these cars appeal to this forum would be full of posts with everyone crying their pride and joy has gone bang, haven't seen any in the year I've been on here so must be ok.

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Don't agree that cars are run flat out in the factory, either with an operator in them or plugged into diagnostic kit and left to their own devices (Health and safety nightmare!) The rolling road facilities they use cost a very big bundle of money and if you were to add even 60 seconds to the test for some running in they could run into capacity issues meaning they can't flow enough cars through to maintain production volumes.

They do pay people to drive them round as you can't duplicate the driver interactions with the car's physical controls and features by a computer alone. And this can take a fair number of people as the drive test will take comparably longer than the rate which cars come off the end of the line, so you need more drivers to process them plus account for test re-runs.

I've got first hand experience of what's involved here, trust me ;)

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It'll be fine, in the manual it'll probably tell you ( they currently do with the 7.5 ) what the optimum cruising speeds are per gear, the new ST is something stupid like 43MPH to achieve max economy ( 58MPG at this speed according to the trip cpu )

I've noticed it's really econimical doing 50 in 6th, that's about 2000 rpm and I've seen the trip showing around 70 mpg on what I thought was a flat road.

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All else I can say if that was the case in testing Will on here wouldn't have had 1mile on the clock when he picked it up, it's impossible to take any car through all rev ranges once in all gears, you've done well over a mile in that case, plus to manually take it though the revs in 6th gear you'd have to have someone driving at 140MPH and well over any regular driving scheme which is set at 70 and they don't employ anyone with advanced police qualifications, I say this because Ford and Mercedes and Mitsibishi were on Mega Factories and it was all on there.

Your method is a H&S nightmare, leaving them alone is not, failsafes and power cut offs will override any known issues, unknown, unforeseeable issues are not a H&S nightmare and not part of the H&S at work act.

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Engines are hot tested before they leave the factory.

They are also tested on a rolling road in the assembly factory and a final bumpy track.

Sent from my iPhone using Ford OC

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