Speed In 5th Gear?

[Guest frenchman97]

Hi Guys, just joined so hope someone can help.

 

My friend bought a C3 demo 2 years ago and I introduced him to showroom as I had a saxo from there at the time.

 

As he is a guy who watches his coppers, he does a lot of 5th gear driving, especially on road to Scotland(like we all would) but he drives very slowly (although ex artic driver) and he can get up to 70+mpg from his C3. he has given me a demo and he can do 25+ mph with any engine labouring.

 

What speed SHOULD I be able to do in 5th gear WITHOUT engine labouring.

 

my situation is that I bought my car new in June 07 (C3 Cool diesel) and I find it shudders/or can do when doing 35 or 37 or MAYBE 39/40.

 

I do know of course that 5th ideally is for motorways but its nice to know you can get into 5th quickly to save fuel.

 

Anyway, I am arguing with company as its under warranty and they are trying to say its my driving, although I've been driving for 50 years, been on an advanced motoring course, and passed my test in an army lorry.

 

Plus, they have changed clutch, changed 2 injectors so I am saying if they think its my driving, why go to that trouble, which did not solve anything.

 

So my question is, what speed should I be able to do in 5th without shudder

 

I have put my complaint in writing to them and Citroen and am waiting.

 

Regards

 

 

George

[kfk]

In my opinion i would say that your driving the vehicle outside of the limits its designed to operate.

 

In the good old days.....and i can go back 25 years when we didnt have engine management systems compensating for our lack of driving skills. Instead we made sure we were in the right gear to give us greatest flexibility from the engine....and to this end we might be lucky to see 35mpg. Of course, if you left your car in 4th gear and had the miss fortune to loose engine speed, you either put your foot flat to the floor to try and get some momentum, or gave the vehicle a quick flick down the box...ussually 2 gears to give the car a chance to cope with the conditions.

 

With todays technology you will find you can leave your car in a higher gear than might have been desirable in the past....and whilst trundling round at 1,300rpm it may produce fantastic fuel economy, but your trading the drivability aspects of the vehicle in doing this.

 

Again going back to the old days most vehicle when shutting the throttle and slowing down , both petrol or diesel would still be sucking/injecting a small quantity of fuel into the engine......with modern systems we have a situation where computers shut the fuel off when they see you are slowing down....its called shut off on deceleration and helps save fuel.....obviously it also has to reinstate injection at a certain point to stop the vehicle stalling aswell.......so here is maybe where your problem occurs.

 

Your trying to drive the vehicle at 1300rpm (or there abouts) on a very light throttle (driving economically), the vehicle will reach the desired speed and you will maintain it by very slight adjustment to the throttle position.......in fact what you are doing is hovering your foot at the fuel shuttof/fuel reinstatement position....and this will give under certain circumstances a fairly violent shudder.

 

In my opinion you dont want to be driving any vehicle below 1,500rpm and ideally keep it above 1,800rpm....but thats my opinion.

 

I might also add that i am aware of the specific shudder your on about and would recommend using a lower gear.......modern cars are very forgiving....under what conditions would you have used overdrive 30 years ago....would it work well at 37mph?

[stimulator]

We have two C3s in our garage. One is the 90BHP 1.4HDi the other the 92BHP 1.6HDi

 

Re 1.4HDi

Experience has shown that driving in 5th gear below 40 mph on all but level roads causes the car to labour and deprives you of the expected performance. On a level road with one up it will pick up from 35MPH. The best RPM range is no lower than 1700

 

Re 1.6HDi

Experience has shown thatd riving in 5th gear below 43 mph on all but level roads causes teh car to labour and really knocks the performance. On level road with one up it will pick up from 37MPH. the best RPM range is no lower than 1800.

 

As far as 5th gear is really for motorways I say NO it's for any speed above 40MPH anywhere anytime.

 

I read recently in an article that with diesels you should change up at 2300 rpm and down at 1800 rpm.

[Guest frenchman97]

We have two C3s in our garage. One is the 90BHP 1.4HDi the other the 92BHP 1.6HDi

 

Re 1.4HDi

Experience has shown that driving in 5th gear below 40 mph on all but level roads causes the car to labour and deprives you of the expected performance. On a level road with one up it will pick up from 35MPH. The best RPM range is no lower than 1700

 

Re 1.6HDi

Experience has shown thatd riving in 5th gear below 43 mph on all but level roads causes teh car to labour and really knocks the performance. On level road with one up it will pick up from 37MPH. the best RPM range is no lower than 1800.

 

As far as 5th gear is really for motorways I say NO it's for any speed above 40MPH anywhere anytime.

 

I read recently in an article that with diesels you should change up at 2300 rpm and down at 1800 rpm.

[Guest frenchman97]

Hi There

 

Thank you both for replying, and I appreciate your comments, thats why I posted.

 

What would be your comments be when I say that we have had the shudder doing 27-30?

 

Also, why would the garage take out clutch (maybe replaced it) and replace 2 injectors if it was my driving?

[stimulator]

At 27 to 30 your revs would be approx 950, which is just above idle speed. I'd expect the car to judder in 5th long before that,

 

Why they changed those items don't know but they obviously thought they were u/s

[kfk]

Sometimes things get replaced because the information given to the workshop is different to what the customer has actually complained about. Other times it can be caused by a poor description of a fault from the customer.... and then you get the other situation.......the customer 'thinks' there is a fault with the vehicle, no one can replicate the fault at the dealership.....but the customer keeps coming back and wont accept the answer no fault found......eventually someone decides to do something, the customer unfortunately now thinks the garage has experienced the fault and feels the garage is now admitting there is a fault.....the part fitted doesnt cure the fault, so the customer brings it back and tells them they havent cured it......again the garage cant recreate the fault, but they also cant convince the customer its normal.....because they havent experienced it.....someone decides to fit something else.....which also doesnt work.

 

Would have been easier if your dealership had the balls to tell you from the outset it was being driven outside of its designed parameters.

[raveydavey]

My C3 will do 30mph in 5th, but it's a lot happier if I'm in 4th at that speed!

 

I'd agree with the posts above - you need to trade a marginal increase in fuel consumption for better driveability and mechanical kindness.