Help with driving a diesel

tjw2007

Tuner
Points
72
Location
Essex
Just bought a 1.7 CDTi SXi Corsa - am really pleased with it although it doesn't seem to have quite the punch of the Kia Ceed 1.6 diesel that I drove a few months ago, despite being more powerful on paper. I've noticed that although there's not much power in first gear, the higher gears seem to get to pretty high speeds at reasonably low revs, was just wondering if diesels are not meant to be pushed to high revs in each gear and if this is by design or whether it's still ok to push the car over 3500-4000 rpm? Although I realise that this would impact on fuel economy.

Thanks
 
1st gear may just be the gearing or it could be the ECU limits the boost to aid traction.
diesels generally have a small power band, with it tailng off very quickly towards the end, so the gearing overall is longer to keep it in as long as possible.
With diesels is best to shift just after max torque as compared to just after the power in a petrol car.
 
The torque peak is the point at which the engine is accelerating the car hardest. If you change up at 3000 that's a good starting point. Basically, experiment with it. Diesels do give of their best if you use the mid range torque. There's not a lot of reward for revving right through the range all the time.
 
In those engines peak power (bhp) is at 3100 and drops off at 3800. When we start talking Torque this comes in strongest from 2400 to 3400 and seems to tail off quite steeply after this.

So I would say the change point should be around the 3400-3800 rpm mark although this does depend a little on gearing. On each upchange you wan the revs to start at the 2400-3000 mark.



A remap will push the power up loads from about 140bhp to a massive 220bhp (try regal autosport and tell them TorqueCars recommended you!)
 
Thanks guys, that's really helpful and explains what's going on. I would definitely like to remap at some stage, but am a bit apprehensive in regards of if I ever wanted to sell or part exchange the car - would it put people off knowing that it's remapped? They might think I'm a boy racer and have knackered the car or perhaps the increased insurance premium might put them off!
 
I haven't yet come across a tuning company that charges to revert the car to standard.

You might even find that the remap is a positive selling point.
 
hmm..that's interesting, now that has cheered me up! Just out of interest, generally speaking what kind of insurance sting do you get if you remap - I mean is it quite a jump or just a little more expensive?
 
Depends a lot on the company. A few ignore it or load 10% some go a bit heavier and other will just refuse. You need to ring around - say the remap gives you better economy (if it really does) as the main reason for going for it. (Do mention the extra power as well but not as your main reason;))
 
Thanks, that's really helpful - I mean 10% on top of an already much lower premium for a diesel is, in my opinion a small price to pay for the increase in performance and mpg you get from a remap - just need to find the cash for initial outlay for the remap now!!
 
Do get a quote first. Some insurers go ballistic over remapping as they know how huge the performance gains are. Quite why that should make you a higher risk driver I don't know but there is probably some data somewhere that supports this. Noticed I avoid the word 'statistics'.

There's also perhaps an element of you want it, you pay for it. Afterall, how do you reward someone who drives a 1.0 Corsa 3 cyl?
 
will definitely get some quotes before I do anything. I imagine there are some 'specialist' insurers that are better to use in the case of customised cars. I'll have a look around.

Cheers
 
Privilege (part of Royal Bank of Scotland for now anyway) is a good place to start. It's the same company as Direct Line, Churchill, amongst others but Priv is the place to start for performance cars rather than the more usual 1.6L things.
 

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