3.0i vs 2.5Si (engine)

M

Mr Whippy

Veteran
 Harrogate
What do people think to these two different engines?

I managed to test drive a 2.5Si today and it felt lovely to drive. Stupidly I forgot to press the sport button :headbang: but either way it was a lovely delivery of power with almost a 'flick' of power at 6000rpm out to 7000rpm... but it was still pretty tractable despite a fair old chunk less torque than the old 3.0i. (I think the final drive ratio was shorter to help here)

Still, it has me wondering how damn good the 3.0Si must now be, and secondly, if getting a 3.0i is necessary when the 2.5Si still offers almost the same bhp/tonne as an older 3.0i outright, while giving more economy, lower tax and possibly lower insurance etc... also, sports seats as standard (though the 2.5's seem generally down on kit as the seats are manual :( )


The 3.0's feel more muscle car (in the SMG, but I need to test a 3.0 manual!), the 2.5Si a bit more racey and revvy... I really don't know which I would like more over the longer period...

I do know I like sports seats though ;)

Dave
 
If you liked it anyway, then with the sport button you'd love it, it does make a difference.
In the "real world" :fuelfire: in many respects it can be more fun thrashing a smaller engined car, and 95% of the time you'll find yourself held up by some muppet anyway. In terms of kit you'll get something that's broadly comparable to a 3.0 (except I'm sure you'd be unlikely to find electric seats on a 2.5Si) but maybe get others such as nav, xenons, etc.

Final drive ratios -

2.5Si - 3.38
3.0Si - 3.23
3.0 - 3.07

Oh and one other thing, there was a long period where the "old" 3.0 was unavailable to order due to emissions, so from about April 05 until the facelift in March 06 there are very few used 3.0 cars.

M sport seats are the best ever :)
 
Whatever the book bhp figures say I'm pretty sure the 3.0i would sail away from the new 2.5 unless you revved the arse off the smaller engine.

Personal choice of course but looking at the bigger picture a 3.0i will generally come with a lot of extras that won't be found on the 2.5 as people who wanted to waste money would have fully loaded the 3.0i. The 2.5 owners may have been just a tad more budget concious. You also get some different things on the 3.0 such as ///M sport suspension, silver headlights, rain sensors, electric seats (double check these by looking line to line in the different bochures)

IMHO it's one of those no win discussions and really you just have to decide upon looking at several cars which most closely fits your needs in terms of colour, engine, toys, costs, mpg, insurance, etc. as they are both great cars.
 
Not sure about the 2.5Si, but when I drove the 2.5i and 3.0i back to back - it felt there was a lot more torque low down, meaning I didn't have to rev it hard to move.
 
cj10jeeper said:
Whatever the book bhp figures say I'm pretty sure the 3.0i would sail away from the new 2.5 unless you revved the arse off the smaller engine.

Personal choice of course but looking at the bigger picture a 3.0i will generally come with a lot of extras that won't be found on the 2.5 as people who wanted to waste money would have fully loaded the 3.0i. The 2.5 owners may have been just a tad more budget concious. You also get some different things on the 3.0 such as ///M sport suspension, silver headlights, rain sensors, electric seats (double check these by looking line to line in the different bochures)

IMHO it's one of those no win discussions and really you just have to decide upon looking at several cars which most closely fits your needs in terms of colour, engine, toys, costs, mpg, insurance, etc. as they are both great cars.
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CJ to be fair I think you are talking at cross purposes, the car in question is the 2.5si, the 2.5 was still available, but not the 3.0i, the 2.5si replaced it.

I dont believe there is that much difference in mpg, I get around 33mpg and tax is 220 per year, not sure on tax on the 3.0i

With regard to electric seats, not really a problem unless somebody else is going to drive the car and needs to move the seat.
 
I was thinking of the old 3.0i (prefacelift) Vs the new 2.5si (facelift) as I though that was the question. Where are my comments wrong?
 
I thought you were comparing the 3.0i to the 2.5i

"Personal choice of course but looking at the bigger picture a 3.0i will generally come with a lot of extras that won't be found on the 2.5 as people who wanted to waste money would have fully loaded the 3.0i. The 2.5 owners may have been just a tad more budget concious. You also get some different things on the 3.0 such as ///M sport suspension, silver headlights, rain sensors, electric seats (double check these by looking line to line in the different bochures)"
 
Yeah, I think the 2.5Si didn't actually feel special or spectacular until it got up near 4000rpm, but up top it did lift it's skirt nicely and put on some speed, so it'd still be quick when needed, just you would have to work it harder more of the time.
I suppose which to choose depends on what you like, the S2000 Honda is the extreme movement of that nature, with similar power to the 3.0i, but it ALL being at the top end...

I think I am a torque man though, and the 3.0's having come with more of the kit I want as standard, and being cheaper, means it is the sensible choice for me ideally.

I just thought it was interesting as the 3.0i and 2.5Si offer a similar power output and power to weight.

I didn't expect the revvier lower torque nature to be quite as intoxicating, but it pulls it off quite nicely :)

Dave
 
Mr Whippy said:
I didn't expect the revvier lower torque nature to be quite as intoxicating, but it pulls it off quite nicely :)
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Yep it's great, and some people talk about diesels having a lot of torque. Can't beat a large capacity petrol engine because you get the torque but also the powerband is twice as wide.
 
I too prefer the feeling of slightly lower rev range 'torque' to push the car forward, rather than the revving to get it all going.

In another life I run a 5.7 litre V8 and the 'hand of god' pushing the Jeep up a mountainside from as little as 1500 revs has to be felt to be believed.
 
Wondermike said:
Mr Whippy said:
I didn't expect the revvier lower torque nature to be quite as intoxicating, but it pulls it off quite nicely :)
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Yep it's great, and some people talk about diesels having a lot of torque. Can't beat a large capacity petrol engine because you get the torque but also the powerband is twice as wide.
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Well, it's all hard to compare.
The car I drove there and back in, my Peugeot 306 diesel, has 280lbft of torque and 155bhp, and only 1130kg, so it's fairly nippy but it's still only got about 3500rpm to play with.

The 2.5Si at first felt slow and gutless down low in comparison, but I was ambling around using only 1/3rd of it's rev range, while in my diesel I use 2/3rds most of the time, so it's easy to think it's faster than it is. Rev it, and it's not that much quicker...
Rev the petrol in this case, and as you say, you have oodles of rev range where it just keeps going and going and that is where you get the reward and enjoyment and performance! One of the main reasons I want a big BMW six pot petrol engine.

Oh, and the throttle and brake were lovely for heel and toe, with the engine spinning up nicely... I did some lovely downshifts and the induction sound was superb. Performance aside it was a very sweet setup. I rekon that 3.0Si is a bit of a monster engine if it revs up to 7000rpm in the same manner!

Dave
 
I own a 2.5si Sport, but have driven the 3.0si, the M 3.2. The 3.0si and M is out of this discussion - but had just mentioned for reference.

To really understand what choice to make, you have to take into consideration your own driving style and the conditions that you most regularly drive in - these factors as well as cost will dictate what you go for.

As other posters have commented - the 2.5si is the probably the most revvy engine in the range but if you look at how it delivers power it is probably the smoothest and most linear in the range also.

Max torque 184 lbft (250NM) is delivered on a flat line between 2750 and 4500rpm thats a range of 1750rpm at max torque output.
This exhibts the tractablity of the motor, but also that it seems to probably have been restricted as the flat line is unnatural.

Most people spend most of their driving in this range and rarely venture past.
Only in very high performance cars do you gain max torque anywhere past 5000rpm.
It kind of harks back to one of the more emotive threads on the forum around real world performance.

The 3.0i was a great engine with slightly bigger headline figure for torque and horsepower; look at the delivery and character, and compare that with the newer efficiencies of the 2.5si and its power delivery and character.

The OP stated that on the test drive they didn't press the sport button - IMO the sport button does make a significant change in the 2.5si responsiveness and gives it real punchyness.

I have found the 2.5si to be really great fun - its light, zingy and powerful whilst being clean and economical - its the best engine for pottling around your city or town with enough poke low down to get to gaps or nip through traffic, and on the open road it is quick enough to stay ahead of most things (driver reliant!) and happy to sing high up on the rev counter exhaust popping and burbling all day - true BMW 6 pot style - for me it really addresses the requirements of both worlds.
 
Go for the M, its chaper and affordable now. U will love it. There is a lot fo power and also a an everyday car. Just p/x 2.5 to M. Tried 3.0si, steering too light, didnt feel like a sports car. My wife's honda civic felt the same except the power. But the M is a different animal. cheers. But at the end of the day- buy what suits ur pocket and what u like.
 
chetalien said:
Go for the M, its chaper and affordable now. U will love it. There is a lot fo power and also a an everyday car. Just p/x 2.5 to M. Tried 3.0si, steering too light, didnt feel like a sports car. My wife's honda civic felt the same except the power. But the M is a different animal. cheers. But at the end of the day- buy what suits ur pocket and what u like.
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Cheaper to buy only - running costs, insurance will all still be higher - but quite rightly get the best you can afford :driving: :driving:
 
Mr Whippy said:
Yeah, I think the 2.5Si didn't actually feel special or spectacular until it got up near 4000rpm, but up top it did lift it's skirt nicely and put on some speed, so it'd still be quick when needed, just you would have to work it harder more of the time.
I suppose which to choose depends on what you like, the S2000 Honda is the extreme movement of that nature, with similar power to the 3.0i, but it ALL being at the top end...

I think I am a torque man though, and the 3.0's having come with more of the kit I want as standard, and being cheaper, means it is the sensible choice for me ideally.

I just thought it was interesting as the 3.0i and 2.5Si offer a similar power output and power to weight.

I didn't expect the revvier lower torque nature to be quite as intoxicating, but it pulls it off quite nicely :)

Dave
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Before I bought my 2005 3.0i I was actually in the market for a S2000. I had taken two used S2000s for a drive on the same day I drove the Z4. I had been wanting a S2000 for years and I was ready to buy. To be honest, as I drove the S2000 I was "trying" to really like it. It was falling short of my expectations. For me, I would almost never drive that car at the RPMs that are required to get to the V-TEC range. When I brought the car back to the dealer there just happened to be a Z4 sitting right next to where the Honda was parked.

The salesman talked me into taking the Z4 for test drive. It was a few thousand dollars more (which was a big deal for me)but I thought I might as well give it a shot since I'm here. As I pulled out of the lot I started laughing because I couldn't believe how much different the two cars were. I was sold before I hit second gear! I guess I'm more of a torque guy too. I liked everything about the Z4. More room in the cockpit, better ride comfort, and the look of the car was awesome. I LIKE IT! :thumbsup:
 
I`ve owned high revving cars and loved them (BMW E30 M3`s) and testdrove a new S2000 but just like you I wasn`t completely sold on it - you really do have to rev hard to make just half decent progress. It was also quite cramped inside with my arm rubbing the door (and I`m skinny). It was about 8 months later when I drove a Z4 coupe - immediateley I was like "yes please, mine mine mine mine mine, don`t let anyone else drive the car I`m going to find me wallet" :driving:

Day to day driving, yep, torque is what you need. I
 
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