Which engine, early 3.0 or 2.5si ?

P

Patrick1964

Member
Hello all, I’m considering a Z4 roadster as a summer / weekend car. I don’t
want to spend a fortune and out and out speed isn’t the main requirement, so the M is a no no. I’m looking to spend up to about £5k, which seems to put me in earlier 3.0 cars with sensible mileage or the later 2.5 si. As the power is similar, my thoughts are that the 2.5 with shorter stroke may be more fun to pedal. I’d be interested in the opinion of anyone who is familiar with both cars.
 
If you like your paint rare this py 2.5si looks great value around £4500
.https://www.ebay.co.uk/itm/2006-BMW-Z4-2-5-si-Sport-Roadster-2dr/163361683036?hash=item26091d765c:g:yGQAAOSw8U9cKPZE:rk:1:pf:1


Doubt you would notice any difference in power in that or earlier Se 3.0
Probably switch the alu dash to black :driving: :)

s-l1600.jpg
 
test drive both :thumbsup:
with the si you have the waterpump to consider at 75-100k miles, the engine also hates short journeys- these can cause the tapping
3.0i had problems with sticky steering and the disa valves i think?
either car is a good choice though
 
That PY 2.5si is lovely 8)

3.0i's are pretty much bulletproof, but you will need to factor in maintenance costs for non engine bits, such as bushes, suspension and electric things. But the same could be said for the 2.5si.

Oh and they do like to leak oil, so look to replace the rocker cover and oil filter housing gaskets. They're pretty cheap and quite easy to do yourself.
 
If your sure you don't need the torque then go for the 2.5, assuming you can find a newer, lower milage car, then that should mean smaller bills. :D

Be sure to drive both before you take the plunge though. You might just find that longer stroke is just what you want for ambling along on those summer drives. Happy hunting. :thumbsup:
 
My first Z4 was a 2.5si and loved it. Compared to the 3.0si I have now, it wouldn’t bother me if I went back to the 2.5si. Not sure how it compares to the M54 3.0 though
 
Chris_D said:
3.0 every time for me.
Youd miss the pull in the 2.5 vs the 3.0.
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Not against the 2.5si, difference are minimal against the 3.0i. As having had daily blats against a 3.0Si coupe when I had my 2.5Si there was nothing in it even. Neither of us could get away from the other when ever we were in front.
 
Chris_D said:
3.0 every time for me.
Youd miss the pull in the 2.5 vs the 3.0.
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N52 218bhp against M54 228bhp :oops: i really doubt there would be any noticeable difference to the average end user , both straight 6 , both equally nice in torque & tone .
Myself i would always prefer to buy newer & throw my money into the facelift 2.5Si car simply because the head lights , rear lights & bumper styles are " facelifted" :wink:
 
Yeah but went you tell people it's a 3 litre under the hood, they look at you like you own some kind of mental supercar :lol: it's really odd that so many non car people expect a smaller engine in these cars.
 
mr wilks said:
Chris_D said:
3.0 every time for me.
Youd miss the pull in the 2.5 vs the 3.0.
Click to expand...

N52 218bhp against M54 228bhp :oops: i really doubt there would be any noticeable difference to the average end user , both straight 6 , both equally nice in torque & tone .
Myself i would always prefer to buy newer & throw my money into the facelift 2.5Si car simply because the head lights , rear lights & bumper styles are " facelifted" :wink:
Click to expand...
Just speaking from my own experience when looking for a zed way back when.
When I gave it the beans in 3rd and 4th on a test drive in a 2.5N52 it just didnt match the push of the 3.0M54.
Probably a marginal difference in power but the delivery of the M54 won me over.

... And having a dipstick counts for something too :lol:
 
I've not had both, but had a 2.5 litre M54 in my E46 Compact and replaced it with an E91 with the 2.5 litre N52.

My experience going from one to the other was a bit like Chris describes - you really need to rev the N52 if you are in a hurry, whereas the M54 felt like it had bit more pull in the mid-range.

I suspect the M54 may cost a bit less in maintenance - especially when the inevitable N52 electric water pump dies. :( (I've had 3 cars with an N52, and 2 dead water pumps to date).

But I can also see the argument for going for a 2.5Si as it will be the facelift model - and possibly more likely to find one with M-Sport seats.

As others have already said I think trying one of each would be the best answer - and would be an interesting comparison!
 
Mr Tidy said:
I've not had both, but had a 2.5 litre M54 in my E46 Compact and replaced it with an E91 with the 2.5 litre N52.

My experience going from one to the other was a bit like Chris describes - you really need to rev the N52 if you are in a hurry, whereas the M54 felt like it had bit more pull in the mid-range.

I suspect the M54 may cost a bit less in maintenance - especially when the inevitable N52 electric water pump dies. :( (I've had 3 cars with an N52, and 2 dead water pumps to date).

But I can also see the argument for going for a 2.5Si as it will be the facelift model.

As others have already said I think trying one of each would be the best answer - and would be an interesting comparison!
Click to expand...

Was your N52 E91 the pre or post LCI 2.5 ?
 
Mr Tidy said:
mr wilks said:
Was your N52 E91 the pre or post LCI 2.5 ?
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It's pre-LCI - build date was August 2005.
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If i'm not mistaken the early 05/05 E90s used a 2.5 as opposed to LCI 2.5 that was a detuned 3.0 N52
Also in a much heavier car than a Z
 
mr wilks said:
If i'm not mistaken the early 05/05 E90s used a 2.5 as opposed to LCI 2.5 that was a detuned 3.0 N52
Also in a much heavier car than a Z
Click to expand...

I think the LCI 325i used a detuned N53 Direct Injection engine - which has it's own issues!

While my E91 is noticeably heavier than a Z4 at 1,445kg, it's actually quoted as being slightly lighter than my 1,480kg E46 Compact that had the 2.5 litre M54.
 
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