TDIs.. When do you change up?

[benuk]

Interested to hear what everyone thinks on when to change up on a TDI (ranging from cold to warm)

Obviously for performance you want to change 4000 rpm ish, and economy just before 2000 rpm.

I'm mostly interested in the in-between i.e. not for max performance or max economy, while being mechanically sympathetic to the engine... how hard do you drive it when warming up? !!

I keep reading TDI's 'like' to be driven hard

I'll start the poll..

 

[Viking]

No point redlining it, if you're after performance. Max torque is available between 1700 and 2500 usually so that's where I change gear. Every so often I give it a blast out to keep things loose though.

 

[cyphnar]

I keep it low down for economy on most drives regardless of temp, booting it when cold is not good, but i don't think changing at low revs gives an issues??

Occasionally I'll boot it but still try to keep the changes between 2500 - 3000, don't tend to push it much further unless I'm being lazy and/or overtaking aggressively. Maybe drivers of mapped TDI's hold it further into the revs because of the map??

-Cyph

 

[sssstew]

Generally yes a harder driven TDI responds better and performs better.

I did up to about 2300 rpm when cold, so they turbo just kicks in properly to help warm up quicker, dont want extra long warm up times, then once warmed up change at about 3k during normal driving and 4k when driving v hard.

Too much grannying isnt good for your TDIs. but only good for economy.

 

[BenO]

Changing somewhere inbetween 3 & 4K in all but first gear once warm gives me around 45 to 50mpg. My driving style has far less impact than, for example, not keeping my tyres inflated.

Since uprating the boost pipework the engine seems to have a wider power band and is much happier at higher revs than at low. While warming up i dont take mine above 2.5K, (warm to me is 10 minutes after the needle hits 90)

 

[Dajmin]

I only really pay attention to the revs when the engine is cold. I tend to change when it needs it, which usually falls around 1750 or so. Hell, the traffic around me means I don't get much choice!
But once it's warm (if I get the chance) I love to clean out the carbs a bit

 

[nightflight]

I try and keep it below 2000ish when it's cold, then once it's warmed up i'll change at around 3000 so that it's still on boost when the next gear's in place.

 

[Gordz]

I just go by how the car feels. Try booting it when it's cold and there is quite a long delay for turbo to kick in and generally engine just doesn't like it. So I keep gear changes nice n early when cold.

And with changing gear when warm, if driving hard to overtake etc. I'll just put my foot down and when feel acceleration starting to level out, I change up. Prefer to keep my eyes on the road than the speedo when going flat out

But I'd imagine it's around 4k. Anything over 4k and there just isn't any power available for a diesel.

 

[jonjay]

But I'd imagine it's around 4k. Anything over 4k and there just isn't any power available for a diesel.

Thats not necessarily true if you start modding.

 

[Gordz]

Only engine mods I have at the moment is a Pipercross air filter!

Don't really pay attention to rev counter, as said I just listen to the engine and feel the performance. But I'll keep an eye on my revs today and report back.

 

[devonutopia]

Does 5,000rpm count as 3,000+?

 

[Muttley]

devonutopia wrote

Does 5,000rpm count as 3,000+?

Yes, it does. I have to ask, though, what have you done to it to get it to produce useful power gains all the way up to 5000 rpm?

I mean, all other things being equal, power is a product of how big a bang you can make (BMEP, which translates to torque, more or less) and how often you can make them (rpm).

As far as I know, diesel fuel burns more slowly than petrol and for our engines, once you get over 4000 rpm you're getting to the point where you can't burn all the fuel in the duration of the power stroke. So although you can stuff more fuel in, most of it goes out the back as smoke and not much goes into making a bigger bang.

One thing that might make a big difference at high rpm is nitrous oxide, releasing extra oxygen right there in the cylinder.

 

[muddyboots]

Thats not necessarily true if you start modding.

Indeed; I regularly take mine to around 4400-4500 when needing maximum acceleration.
Without the remap though, it just used to die around 4000.

 

[Tartan58]

90% of my driving is in town so I tend to go for 1500-2000 whatever the engine temp as I'm rarley going over 30, although I do try and give it a blast up to higher revs now and again when I do get on an open road to keep things loose.

Don't know if I'm imagaining it but there I definatley feel a noticable differance after giving it a good blast following a week of town driving.

 

[Martin_DSG]

I let the DSG do it all for me im lazy.

 

[devonutopia]

My modifications are plentiful but to be honest, 5000 is still a waste, but there's more than enough power still at the 4,700rpm redline to want to hit it all the time. We'll see what my new setup will provide as I am aiming for over 300bhp - Just not sure where all the power will be in the rev range.

 

[Husbandofstinky]

Hardly ever take to the 4 mark only every now and then to clear the crap out.

Mostly its 3's.