308 - speed limiter

[Degeneratemoo]

Is using the speed limiter the most fuel efficient way to drive a 308? The trip computer seems to indicate that the car does much higher MPG with the limiter on driving at a steady speed. Would there be any risks to the car I.e. Is the speed limiter likely to break through overuse etc...

[Citroenmad]

Im guessing you mean cruise control, were the car keeps to the speed you set it at?

The speed limiter is to stop you going over your set speed, unless you really floor it.

Cruise control does often increase MPG, as the speed is maintained, your not creeping up from 70-to say, just sat at a constant speed.

Though it does differ between different cars.

The speed limiter and the cruise control is only the ECU telling the car what speed to do, so no mechanical items to wear out.

[addo]

I've found cruise not so efficient as trying for a steadier engine load (ie; maximum intake vacuum).

However, it does get you past a lot of non-cruise drivers as they slow down on long climbs or irrationally brake on sweepers. Normally I set mine at 2-3 over the limit and plan corners to avoid any braking. That forced planning, might well be part of the fuel saving mentioned above...

[Degeneratemoo]

Thanks for the replies, I did mean the speed limiter, not the cruise control. I have a set drive to work, roads quite windy so I wouldn't want to have cruise control on, but set the speed limiter to the max speed of the road. In theory this should give max speed with lowest engine load wouldn't it?

[Citroenmad]

Ah right, sorry.

Im not sure, i wouldn't think it would have a lot of difference, but it might effect MPG in a slight way, as again your not going over a set speed.

[Degeneratemoo]

Drove to work tonight using speed limiter 95% of the way. Over 25 miles I got 39.7mpg. Bit disappointed compared to the 47mpg I used to get from my 206 but I know this has a bigger engine.

I will drive home in the morning without the limiter and see what I get.

How many miles do most people get out of a full 308 tank?

[Degeneratemoo]

Driving back from work today, very snowy and slow going so not really a direct comparison to last night, but, I got 36.6 MPG over the same 25 mile journey. Will continue to monitor...

[mookev]

Hi ya. Just wondered how you're doiing with you 308.ive had mine 18 months and it averages 37mpg worse than a 1.6 Astra I sold...also uses oil but I gather this is normal..Kevin

[Paul-R]

Just looking at Degeneratemoo's profile and you could be in for a long wait for a reply. He joined on Thursday Jan 6th 2011, came back on Friday Jan 7th 2011 and hasn't been seen since!