BMW Z4 28i vs 20i

[steamdave]

I'm considering buying a Z4 (but also considering other makes/models).

It is the 28i Msport version that I'm interested in, but they are not around in abundance, particularly with auto box and well spec'ed. None for sale at the moment in Ireland, where I live. Much as I would like the 35i, I can't justify paying an annual road tax of 1200 EU for a 3rd car in the family. So. I may have to lower my sights and look for a 20i Msport.

My questions are: What did BMW do to the 2 litre engine to up the power by about 30% from 184 to 245 bhp? Presumably the uprated engine wasn't overstressed (or was it?) putting out the extra power.
Did they uprate the oil or water cooling systems, uprate the gearbox or brakes or were these components standard across all power outputs?

Dave
The Emerald Isle

[Earthdweller]

Your best asking on the Z4-forum.com where there will be a wealth of knowledge on the E89

As far as I’m aware the engines are the same just different map

A friend has a 20i which is running around 300bhp. There are numerous running around 280bhp

Personally I don’t think I’d be paying a premium for a 28i over a 20i

[ruggedscotty]

Earthdweller said:

Your best asking on the Z4-forum.com where there will be a wealth of knowledge on the E89

As far as I’m aware the engines are the same just different map

A friend has a 20i which is running around 300bhp. There are numerous running around 280bhp

Personally I don’t think I’d be paying a premium for a 28i over a 20i

z4 has a 2.0 engine in both. just a different tune. the base 2.0 engine responds well to a tune. just buy th3 2.0 and have it remaped - dont do a tuing box, you really need to remapt it to get the best.

[Mr Tidy]

I spend a lot of time on z4forum and from what I have read the 18i, 20i and 28i all have the same engine, so mapping an 18i or 20i should get you to slightly higher power output than a standard 28i.

AFAIK the only difference was that 28is had bigger front brake discs, but there are just so many more 20is to choose from!

[steamdave]

Thanks, Gents for your replies.

Looks like I can look for a 20i and get it 'sorted'.

Dave
The Emerald Isle

[lonny]

Uk centric z4 forum is a good start for you - https://z4-forum.com/forum/viewforum.php?f=44

I’ve wondered about this question before. I know both engines are 2.0 but do you need stronger conrods, a bigger turbo etc for the 2.8? I wonder if anyone has compared the parts now across the 2?

[ruggedscotty]

the engine in the Z4 is the same in the three models...

18i 20i and 28i all use the same n20 engine with the same internals, its only the map that differs.

However be aware the 28i has beefier brakes than the 18i ! the three states of tune are :-

158hp
184hp
245hp

[Deep Thought]

steamdave said:

I'm considering buying a Z4 (but also considering other makes/models).

It is the 28i Msport version that I'm interested in, but they are not around in abundance, particularly with auto box and well spec'ed. None for sale at the moment in Ireland, where I live. Much as I would like the 35i, I can't justify paying an annual road tax of 1200 EU for a 3rd car in the family. So. I may have to lower my sights and look for a 20i Msport.

My questions are: What did BMW do to the 2 litre engine to up the power by about 30% from 184 to 245 bhp? Presumably the uprated engine wasn't overstressed (or was it?) putting out the extra power.
Did they uprate the oil or water cooling systems, uprate the gearbox or brakes or were these components standard across all power outputs?

Dave
The Emerald Isle

Its a very tunable engine and i'd have no doubt you could remap it easily to 28i power levels. I'd it in my Cooper S and had mine modded to around 240 BHP.

Personally i'd rather do that than pay potentially £,£££s extra for a 28i.

I'd spend extra for a six cylinder variant, but not for a 28i.

We ran a black 20i for three years and loved it, btw

[steamdave]

Deep Thought said:

Its a very tunable engine and i'd have no doubt you could remap it easily to 28i power levels. I'd it in my Cooper S and had mine modded to around 240 BHP.

Personally i'd rather do that than pay potentially £,£££s extra for a 28i.

I'd spend extra for a six cylinder variant, but not for a 28i.

We ran a black 20i for three years and loved it, btw

Over here in Ireland, the road tax on the 20i and 28i is the same at 590EU but for the 23i, it jumps up to 1120EU. And as mentioned earlier, the 35i would be 1200EU. These rates are based on emissions.

I take your point about getting the 20i and using the savings to get the engine remapped.

It's all moot at the moment because there is (as far as I know) only 1 Z4 2012 - 2015 (which is what I would be looking for) for sale in Ireland.

Dave
The Emerald Isle

[Deep Thought]

steamdave said:

Over here in Ireland, the road tax on the 20i and 28i is the same at 590EU but for the 23i, it jumps up to 1120EU. And as mentioned earlier, the 35i would be 1200EU. These rates are based on emissions.

I take your point about getting the 20i and using the savings to get the engine remapped.

It's all moot at the moment because there is (as far as I know) only 1 Z4 2012 - 2015 (which is what I would be looking for) for sale in Ireland.

Dave
The Emerald Isle

I'm in NI, so just up the road from you!

The 23i was a 2.5 litre. I meant the 30i variant with the 3.0i litre.

I'd be more than happy with another 20i and a remap rather than a 28i. If i was putting 28i money in, i'd go 30i to get the straight six 3.0 litre, but your taxation regime is different so a moot point.

Any scope for importing one from the North or the UK mainland? Might be worthwhile to get the car you want?

Also try facebook.co.uk but search in NI. I take it you've tried donedeal.ie?

Edited by Deep Thought on Monday 27th July 12:57

[steamdave]

Deep Thought said:

I'm in NI, so just up the road from you!

The 23i was a 2.5 litre. I meant the 30i variant with the 3.0i litre.

I'd be more than happy with another 20i and a remap rather than a 28i. If i was putting 28i money in, i'd go 30i to get the straight six 3.0 litre, but your taxation regime is different so a moot point.

Any scope for importing one from the North or the UK mainland? Might be worthwhile to get the car you want?

Also try facebook.co.uk but search in NI. I take it you've tried donedeal.ie?

I've had a look at UK/NI sites and there are a few alright. Only problem is that I'm not prepared to travel to UK under the present cv-19 situation.
To give you an example of what delights the Irish Revenue have in store for imported vehicles (new or used), I've just found one for sale
https://www.theaa.com/used-cars/cardetails/94-1537... When it lands on Irish soil, I will have to fork out an extra 7480 EU within 28 days for the privilege of using it over here. The amount is based on what the Revenue call the Open Market Selling Price. So, even if I got the car for £5.00, I would still have to pay the 7480 EU. Barstewards!

Dave
The Emerald Isle

[Mr Tidy]

steamdave said:

I've had a look at UK/NI sites and there are a few alright. Only problem is that I'm not prepared to travel to UK under the present cv-19 situation.
To give you an example of what delights the Irish Revenue have in store for imported vehicles (new or used), I've just found one for sale
https://www.theaa.com/used-cars/cardetails/94-1537... When it lands on Irish soil, I will have to fork out an extra 7480 EU within 28 days for the privilege of using it over here. The amount is based on what the Revenue call the Open Market Selling Price. So, even if I got the car for £5.00, I would still have to pay the 7480 EU. Barstewards!

Dave
The Emerald Isle

So "free trade" within the EU has a pretty loose definition of the word "free" then!

That is a classic example of why I am glad the UK is leaving - it hasn't turned out to be what we signed up for!

[Dizeee]

I thought the 18 and 20 were 2.0 NA 4 cylinders, and the 28 was a 2 litre Turbo 4 Cylinder? Or was that pre 2010 era?

I drove a 2009 23i highline ( white and red interior ) last year during my investigations, and felt it quite underpowered. Pretty sure it was supposed to be 180bhp. Also, I am sure it was a 2.5L 6 cylinder.

[Deep Thought]

Dizeee said:

I thought the 18 and 20 were 2.0 NA 4 cylinders, and the 28 was a 2 litre Turbo 4 Cylinder? Or was that pre 2010 era?

I drove a 2009 23i highline ( white and red interior ) last year during my investigations, and felt it quite underpowered. Pretty sure it was supposed to be 180bhp. Also, I am sure it was a 2.5L 6 cylinder.

The 2.0 in the E85 variant (2002-2008) was a 2.0i NA.

In the E89 range (2009 onwards) the sDrive20i was introduced in 2011 with a 2.0i Turbo producing 181BHP superceding the sDrive23i which was a 2.5i NA engine. The sDrive28i sat above that with a 2.0i Turbo producing 241BHP.

The sDrive18i was introduced in 2013 with a 2.0i Turbo engine and was a detuned 154BHP variant of the sDrive20i.

[Dizeee]

That's as I thought then. So did the 23i cary on being made at the crossover point? I am convinced now I have thought about it that the car I drove was a 2011 model, not a 2008. I think it was either a 11 / 61.

[Deep Thought]

Dizeee said:

That's as I thought then. So did the 23i cary on being made at the crossover point? I am convinced now I have thought about it that the car I drove was a 2011 model, not a 2008. I think it was either a 11 / 61.

Yes. They made the sDrive23i 2009-2011, so there was probably a fair percentage built and registered in 2011.

It was really 2012 before the sDrive20i came on stream. Some were reg late 2011 but its not until 2012 that you get any great amount of them.

[Dizeee]

If it weren't for my kids i would be driving a Z4 35is now. However, I am happy with my current steed.

[Deep Thought]

Dizeee said:

If it weren't for my kids i would be driving a Z4 35is now. However, I am happy with my current steed.

I've a Z4 and that engine. Just not in the same car

Z4 Coupe and M140i.

Z4 35iS would be amazing, but incredibly rare and they are pricey.

[rassi]

Deep Thought said:

Dizeee said:

If it weren't for my kids i would be driving a Z4 35is now. However, I am happy with my current steed.

I've a Z4 and that engine. Just not in the same car

Z4 Coupe and M140i.

Z4 35iS would be amazing, but incredibly rare and they are pricey.

Z4 35iS: N54 engine
M140i: B58 engine

[Dizeee]

Deep Thought said:

I've a Z4 and that engine. Just not in the same car

Z4 Coupe and M140i.

Z4 35iS would be amazing, but incredibly rare and they are pricey.

The 140 is a B58 engine, the Z4 35IS was the N55...