Two silly questions

[roachcoach]

I should probably know these, but knowing what I don't know and asking those who do has served me well this far in life so....

Silly question #1: Should a car be revved hard periodically?


Now then...hear me out...

I ask since, in the main, I use the motor for commutes. As a result I tend keep her at about 1.7-2k rpm of a possible 7-7.5k (Maybe higher, only even went as far as the start of the redline at 7). I try and keep the revs low for two reasons a) It's a pretty quick machine and it REALLY shifts right though the high revs and to a lesser extent b) saves a bit of fuel.

I figure I'm commuting, not a lot of point in burning fuel/over accelerating/accidentially speeding *big time* (it's all too easy) so I favor just sitting back and taking it easy. With low revs I need to make a conscious decision to welly it.


But it got me to wondering, should I boot it right up to the redline or thereabouts every so often? The turbo is rarely more than 1/4 boost, if it's any persepctive. Any risk of clogging or anthing like that if it's rarely taken over 4k? If so, how often? Once a Week? Once a drive?



Silly question #1: As a footnote, is it possible for a speedo to lag? I notice if I'm giving her "ze beans" and I take my foot off the gas completely, the speedo keeps rising a second or so afterwards. There's not much in it and I've done no scientific testing. Could just be momentum but I've never noticed it in other cars. Although to be fair my other cars weren't as quick.

Thanks folks.

[Phage]

1) Not sure, But it does sound like you're lugging the motor a bit. I usually change at 2500 if I'm not booting it. Certainly a good long blast would be fun, even if it doesn't help your engine at all. ;-)

2) Speedo or Tacho ? Speedo usually driven off the gearbox, so would indeed have a lag from the moment of throttle input.

[roachcoach]

It's ok actually, she starts lugging just under 1500, so I keep it a wee bit higher. Usually I upshift at 2.2-2.5 if I'm "commuting" that is. If I'm "driving" it's a lot higher.

Speedo, so that clears that up, I'm not hallucinating


Belting it is criminally good fun, just in a commute I find having it on a bit of a "leash" is actually quite handy to avoid accidentally over-egging it better to close the gap in 10 seconds than 4 sort of mindset. To be honest I usually end up right now doing it at least once a week, but I try and restrain myself.

[scaryjim]

Do you have a local motorway you can do one or two junctions on every so often? Nothing like pulling onto a motorway to stretch the engine and gearbox (not the way I drive, anyway )! I can't think of any reason that it would be bad for an engine to not be revved up, but as Phage says, it's fun to open up once in a while (I used to love my Rover that'd do 30 in 1st....)

[roachcoach]

Oh there are plenty of opportunities, I'm just wondering if there's a sound mechanical reason to do it.

Potential minor trouble is, I can't really do it in 3rd or higher save on private ground!

However a rev-range blast in second or a partial one in third should make sure most of any postive benefits are felt if there are any.



I've no reason to think it would be bad not to, but it can't hurt to ask

[Konan555]

I tend to drive the Subaru in a fashion that very rarely spins the turbo up (cuts in at 2500ish). I did this for about 3 weeks when I first had it and it developed flatspots and judders. A good fast run cleared it out.

Living in Norfolk, 25% of road users have Nissan Micras and have licences dating beyond the invention of roundabouts. The first step in a service on these at a lot of local garages is a good thrash up and down the main road for five minutes.

As for sound mechanical reasoning... I'm fresh out of that. Pure observation I'm afraid.

[Moby-Dick]

Living in Norfolk, 25% of road users have Nissan Micras and have licences dating beyond the invention of roundabouts. The first step in a service on these at a lot of local garages is a good thrash up and down the main road for five minutes.

a.k.a. the Italian Tune-up

I use the Stagea for a 100km commute and due to the M1 roadworks I dont go above 50 very often either. I dont think you should quite redline it from cold , but going for a little bit of a spirited drive once in a while doesn't do it any harm.

[Ferral]

You need a silly answer if its a silly question, so heres my contribution :

No, dont over rev it or the wheels and exhaust will drop off

On a serious note though, I dont drive yet (doing it July this year). But from previous driving lessons I was told to watch your revs and keep them in check with the gear you are in. Ideally you dont really want to be going over about 3500 maximum as it stresses the engine (I look at this from an engineering point of view). It wont harm though once a week taking it onto a motorway for a half hour and letting loose, this will help push any crap that is in the engine out and keep things running smooth.

[kalniel]

Speedo will be lag - as soon as you stop providing an accelerating force then your car starts to slow down. Momentum never causes an increase in speed.

Petrol cars don't need much clearing out, but you should definitely ensure that you at least do a longish run to keep the battery in good nick. Crud does build up on EGR valves and injectors but a longish run where the engine stays at optimal temperature for a decent length of time will clean them up - revving higher just means that happens faster, but you shouldn't do that until everything's up to temperature anyway.

[Moby-Dick]

. Ideally you dont really want to be going over about 3500 maximum as it stresses the engine (I look at this from an engineering point of view).

I dont quite agree with that - 3500rpm on my old oil burning xantia felt like the wheels are going to fall off , but its a happy howl from the straight 6 in the Stagea . its just above tickover for a honda

[roachcoach]

Cheers folks.

She gets a good run 5 days a week twice a day, I'm not worried about revving it hard, it is kinda made with that mind mind. More worried about NOT revving it hard.

If I put my "hooning hat" on for a moment, its positively pedestrian before 3500-4000 only after that does she wake up. But, generally, I'm sitting at half those numbers so wondering if I should make more of an effort to spool up the turbo fully/use the whole range now and again. It's not that big a problem right now (novelty still in effect) but I want to prevent future problems if possible so if I should make a point of using the whole range once a [long]drive/week/month/whatever I would do.

I'd say right now it goes to 5k at least once a week, 7k maybe once a month but I expect those frequencies to reduce as I lose the novelty. I don't keep it there either, just upshift at those numbers.


And it's NEVER ragged form cold, I don't go over 3k rpm, try not to go past 2.5k and low throttle prods until the oil is stabilised at running temps (have a gauge so I can see it)

[Moby-Dick]

Sounds like you are probably doing alright I'm sure you posted before , but what have you got ?
I've driven some turbocharged cars with very long spoolup times , so used to power coming on in one big fat lump

[roachcoach]

Focus ST. Boost comes on very lightly after about 1500 will rise to about .25 and hold steady there up to 3.5-4k (ish). After that, it lets it come full on (seems to overboost a fraction to maybe .6-.65 [I'm not looking closely] then settle back to 0.5 bar past 4k right the way to the redline).

Took some getting used to having the power delivered in two phases like that I can tell you. Never had a car before that surged when you wanted it to, then when it realises you really want to shift it puts even more power out. It's not turbo lag, it's deliberately limiting the turbo at low revs.

It's a strange car, the revs I usually keep it at, you'd never know it wasn't a 1.6 from the engine noise, or lack thereof, open the throttle though it its a different critter altogether.





Actually, to hijack my own thread....has anyone debadged cars themselves before? Is it as easy/hard to go wrong as the common wisdom on the internet suggests? I'm considering whipping the ST badge off (and if anyone can think of a cheep, effective way to conceal twin exhausts I'm all ears [Though I think that's a hiding to nowhere].

[Moby-Dick]

I'd guess that boost is electronically controlled in the Focus - a few cars will run a slightly lower boost in 1st/2nd - its only when you get into 3rd you can get full boost , but running the level of boost you are after should give you a pretty quick spoolup ( note there is a world of difference between spoolup time and turbo "lag" - though the terms are often interchanged. )

[kalniel]

Yeah, the A3's relatively weak clutch was 'fixed' by a software 'upgrade' that just limits torque in 1st gear. Not sure it gives quite the desired effect as now when I want to pull away quickly I'm into 2nd as quickly as I can and slipping the clutch if the revs weren't high enough to get the boost online.

[roachcoach]

Yes, it definitely will be, it is impossible no matter how much gas is applied to get more than .25 bar under 3.5k RPM. I guess it would be nice if it was a smoother transition, but I'm used to it now.