b25 - what's all the fuss?!

[pony]

So basically high compression engines Sports are lighter and quicker than low compression engine Sports ?

Certainly are - but later ones have the lower 3.91 diff innit.

Strange that BMW quoted bhp figures same 170 v 171
Torque virtually same
Accekeration 0- 62mph 8.3 seconds
Top speed 138mph
Is these stats correct according to your knowledge of BMW literature / brochures etc ?

[Speedtouch]

Yes, those are the official figures, and are realistically achievable on most 325i's in good condition, including the SEs.

I had a 1988 325iSE 2-door with the high compression engine and later Motronic 1.3 ECU and it was good for 0-60mph in 7.3 sec and 138mph. I then fitted a Mild chip and it would do the 0-60mph dash in 6.7 sec and top out at 140+ mph (indicated). Very impressive, I thought, for what was then a 30 year old car with well over 100,000 miles on the clock.

[pony]

How do you know would do it in 6.7seconds ?
Did you have proper timing equipment eg race Logic

6.7 is nearly E46 330 territory
I would be very surprised / suspicious of anyone that claimed they can get a standard 325i to do 0-60 in under 7.5 seconds
6.7 is quick considering only had a chip

[jonb]

3.91 so can embarrass newer BMWs

The only 520d's you will be passing are the ones on the back of a transporter

How much does your phat zorst give at the spare wheel?

[pony]

I am getting 167.8bhp and about 1200kg as mine does not have many options
I love lighting up the rears at the traffic lights Michael Schumacher / Schuey stylee

[jonb]

The early engines do feel more urgent than the later ones Ive found.

[Jesus325iTouring]

It is only 35-50hp we are talking here, its not a 150hp jump like an S50 vs b25.

You might find the engine needs a lot of love as Brian has said, a B25 touring should be quick (like hot hatch or 2l saloon quick) but is no way fast like an m3 or similar.

Factor in another 20-25hp by going 2.8 and then it makes more sense.

I didn't find my 320 to be that slow to be fair and the B20 in the e21 is enough for the lighter car to still be quick.

Oh and one huge factor - what diff have you got in it? a b20 with 4.1 feels about the same as a b25 with 3.64 up to about 50.
Combine a 4.1 with a b25 for surprising acceleration followed by diff munching in 6 months time.

Explain this too me again if you'd be so kind, my Touring was a 320i, now 325i.
What diff does it have?
Will it accelerate quicker or slower?
Will top end be higher or lower?

[sweep]

4.27 diff jesus ?

[Jesus325iTouring]

I've no idea Pete, how can I find out?

[sweep]

Should have a tag on one of the back plate bolts ...it will need wire brushing up to read it

[Jesus325iTouring]

Think that'll have to wait until tomorrow then, i'm not so desperate to know to go out in the rain and dirt with a wire brush!

[bss325i]

How do you know would do it in 6.7seconds ?
Did you have proper timing equipment eg race Logic

6.7 is nearly E46 330 territory
I would be very surprised / suspicious of anyone that claimed they can get a standard 325i to do 0-60 in under 7.5 seconds
6.7 is quick considering only had a chip

One of the motoring mags that tested a tech 2 sport when new managed to get 6.8 to sixty.

[jimbom30cab]

Can you get to 60 in 2nd gear in a 325i with 3.64 diff or 3.91 diff?

[jonb]

Think that'll have to wait until tomorrow then, i'm not so desperate to know to go out in the rain and dirt with a wire brush!

The 325i touring always had a 3.9 diff.

[jonb]

Just noticed yours was a 320i before. They normally have a 4.1 small case but you will have to have a gander.

[pony]

Can you get to 60 in 2nd gear in a 325i with 3.64 diff or 3.91 diff?

I have 3.91 and I can't get to 60mph in 2nd

I had New Porsche Boxster in 2012 and got
- 80mph in 2nd
- 117mph in 3rd
What a car !!!!

And the noise !!!!
The heated seats were very very toasty !!!!
The sound system !!!!

[pony]

How do you know would do it in 6.7seconds ?
Did you have proper timing equipment eg race Logic

6.7 is nearly E46 330 territory
I would be very surprised / suspicious of anyone that claimed they can get a standard 325i to do 0-60 in under 7.5 seconds
6.7 is quick considering only had a chip

One of the motoring mags that tested a tech 2 sport when new managed to get 6.8 to sixty.

I would be interested to know what conditions were eg near empty or full fuel tank
Any passengers ?
Any precisely how they do the launch to get that time !

Bear in mind E46 330i can do 0-60 quoted by BMW in 6.5 seconds

I had a race against Kos in his Touring
I had a bit too much wheelspin of the line but a Sport to keep up with 330i (2 generations newer) seems a bit hard to believe.

[jimbom30cab]

My 540i did 110mph in 3rd.

[Simon13]

So does my e36

[pony]

My M3 CS only does about 100 in 3rd

PS
Simon / Jim were your cars standard or not ?

No good saying that if your cars are modded

[jimbom30cab]

yes standard

[DanThe]

3.91 so can embarrass newer BMWs

The only 520d's you will be passing are the ones on the back of a transporter

How much does your phat zorst give at the spare wheel?

Would that be a 520d with 20 years more technology and a turbo strapped to the side of it?

[Brianmoooore]

I've never had any problem getting an E30 to match the acceleration times in the handbook, either. I think it's generally accepted that the figures in the book are on the conservative side.

[Jesus325iTouring]

Just noticed yours was a 320i before. They normally have a 4.1 small case but you will have to have a gander.

I'll see if you're right tomorrow

[pony]

3.91 so can embarrass newer BMWs

The only 520d's you will be passing are the ones on the back of a transporter

How much does your phat zorst give at the spare wheel?

Would that be a 520d with 20 years more technology and a turbo strapped to the side of it?

If bss325i is correct then a Sport can hammer new 520d to 60mph !!!!

[87mtech27]

I remember watching this a while back...

[youtube][/youtube]

[Cloggy Saint]

The 325i touring always had a 3.9 diff.

Really? I was advised to get a 3.64

[Brianmoooore]

If you're buying one, go for a 3.76. My touring was changed to one of these when the gentle whine from the original diff. suddenly changed to a very loud whine, and although I didn't notice the reduction in acceleration, I did notice the improvement in fuel economy.

[maxfield]

The only 520d's you will be passing are the ones on the back of a transporter

How much does your phat zorst give at the spare wheel?

Would that be a 520d with 20 years more technology and a turbo strapped to the side of it?

If bss325i is correct then a Sport can hammer new 520d to 60mph !!!!

On paper.

Let's face it E30s are average now day and age. But none of us here because they are breath taking fast.

[jonb]

The 325i touring always had a 3.9 diff.

Really? I was advised to get a 3.64

It doesnt really matter tbh but the 3.9 was just fitted to offset the extra weight on the touring I presume.

It was put onto the sports because of the first 3 gears being longer than the standard box.

[jonb]

3.91 so can embarrass newer BMWs

The only 520d's you will be passing are the ones on the back of a transporter

How much does your phat zorst give at the spare wheel?

Would that be a 520d with 20 years more technology and a turbo strapped to the side of it?

Yup. And about 20 years more girth

[Andyboy]

If you're buying one, go for a 3.76. My touring was changed to one of these when the gentle whine from the original diff. suddenly changed to a very loud whine, and although I didn't notice the reduction in acceleration, I did notice the improvement in fuel economy.

Seconded. I had a 3.91§ in a 325i Touring manual (they were all 3.91's iirc) and I replaced it with a 3.64 I got for free. The difference in motorway cruising speeds was very noticeable, both in economy and engine noise.

[Grrrmachine]

The 325i touring always had a 3.9 diff.

Really? I was advised to get a 3.64

Gearbox choice affects this. Did you keep the Getrag 240 box when you did the engine swap, or move to the 325i's G260?

I used the 240 with a 3.64 diff in my Touring, and it's a good mix.

[Cloggy Saint]

I'm using the box from the 2.5.

[jimbom30cab]

I'm looking for a 3.91 if anyone has one for sale?