E36 325d vs E46 320d

[Jakeymd]

Discuss which would you have and why?

 

[geraint13]

hard choice, got the 325tds, and the 320d has similar power. would go for e46, purely cause i think more can modded on the e46.

 

[jarrus]

hard choice, got the 325tds, and the 320d has similar power. would go for e46, purely cause i think more can modded on the e46.

I don't know, the E36 would be easier to mod as there is less electrical stuff to by pass.

I'd go for the 325tds, an old work horse engine. But to be fair, I'd rather have a 330d e46...

 

[obi_waynne]

The 325d is a nice engine to work on so that would get my vote. I guess it depends if you plan to mod it or stick with the standard power and setup. If you were not going to mod it then the E46 is the better choice.

 

[HDi fun]

Take the later one if you want the simple option of remap tuning. The later 150bhp 320d will go to over 210bhp.

 

[geraint13]

thats what i thought paul, but am still happy with tds and still puts a smile on the face.

 

[jarrus]

Is your a manual or auto Geraint?

 

[HDi fun]

thats what i thought paul, but am still happy with tds and still puts a smile on the face.

It's a good and well respected car with what is probably the finest six cylinder turbo diesel engine offered before the advent of common rail diesels.

Vauxhall used it in the Omega 2.5 TDS. GM later installed a 4 cylinder 2.1 DTi unit. It was SLIGHTLY more frugal but the power delivery (what there was of it, and there wasn't much) was crude by comparison.

You're driving what I consider will become a future classic. It was the turning point for diesel engine refinement. 6 cylinders help massively, of course. But that's classic BMW through and through.

 

[jarrus]

I'd take the 325TDS as a side project car,

Plenty of potencial to make it indecently fast....

 

[geraint13]

@ jarrus, got the manual mate. going well. flew through the recent mot, with no advisories. not bad for a 15yr old lady.

was talking to a mate the other day who had an auto an had it remapped and he said it was worse than before. i think he didnt get it mapped tidy. does it matter if the box is auto or manual ? does it make that much of a difference ?

 

[jarrus]

Wouldn't of thought so,

A properly done remap should always be better than before.
Did they do a coupe version at all?

 

[HDi fun]

Autos and manuals can be remapped equally. Some operators are a bit unscrupulous and just over-write the whole ECU. Clearly this is not good if they upload a generic map from a manual car onto a similar automatic model with ECU controlled transmission.

 

[jarrus]

What he said,

G, just get your car mapped and be done with it

 

[geraint13]

im £220 into my £400 hundred target mate. not long mate lol.

 

[HDi fun]

There are some tuners out there who will map the 325tds 143 engine. Despite being mostly mechanical in design there is a degree of computer control which can be enhanced, much like PSA's 2.1 litre XUD-T diesel engine can be enhanced.

The results, although impressive, are not as startling as results achieved with common rail engines.

However, your 325tds is a straight-six - this is a very good configuration, especially for diesel engines, due to it's inherent simplicity and smoothness. It's the simplest configuration that offers perfect primary and secondary balance, and does all this without the need for any balancer shafts at all!!

Straight six engines can be long and as such won't rev as high as a V6 but this is no issue with a diesel engine.

 

[jarrus]

I don't see why a V6 will rev higher than an I6, BMW made there living off high revving I6's.

Please fill me in Paul

 

[jarrus]

Also not all the 2.1 XUDT had the Lucas/EPIC injection system, a number of the early engine as fitted into the Citoren XM were fitted with the Bosch VE pump. The Bosch is inherently stronger and is capable of producing more power than the Lucas system because it can be modified internally. As far as I'm aware the ECU of sorts that was used on the Lucas system was used to control the injection advance. If it could be used on the bosch some how to advance the injection timing then top end power would improve.

 

[HDi fun]

I don't see why a V6 will rev higher than an I6, BMW made there living off high revving I6's.

Please fill me in Paul

A V6 is shorter, therefore less flex in the crankshaft and camshafts which allows for higher revs. That's the only reason.

BMW is unusual, although not unique, in sticking with the I6 configuration. Apart from the M series sixes the engines are not particularly high revving. Mine won't go past 6300rpm, for example. Some of the 12 valve engines are lower than this.

Most have gone to V6 setups now for packaging reasons, especially with FWD cars.

 

[jarrus]

I was talking about the M cars specifically really, the E46 m3 can rev it's 3.2 straight 6 to 8.5k and as road engines go that's high.

 

[HDi fun]

The M series cars' engines are very different. The usual reason for using a V6 is for its compactness and a by-product is its ability to take higher revs in general.

They (the M engines) use hollowed out camshafts and all sorts of other tricks to reduce rotating/reciprocating masses and increase torsional rigidity.

In the distant past there have been inline eights on offer by some makers but back then engines rarely revved to more than 3000rpm so torsional rigidity wasn't a problem. They also were not dishing out the torque that modern engines can dish out.

A disadvantage of the V6 is the fact that the crank is supported in only four main bearings, as opposed to the seven used for inline sixes. You can have a four bearing straight six, which would be slightly shorter but this is not perfect either.

Basically - all engine designs are compromises.

 

[jarrus]

An engine made from a ceramic material would be a good engine but probably heavy, you could use water instead of oil as a lubricant.

 

[HDi fun]

An engine made from a ceramic material would be a good engine but probably heavy, you could use water instead of oil as a lubricant.

I don't have much knowledge of current ceramic technology, it's of which I have relatively little knowledge.

However, I can't see this working due to the crystalline structure of ceramics. There's more chance of a ceramic/polymer composite working as an engine material but, again, I am not a specialist.

You can't use water as a lubricant - it boils at 100 degrees C and even if you could overcome this with a pressuried system you'd have horrendous sealing difficulties. Water molecules are very very small. You'd also have problem with surface tension so unless everything was literally microscopically clean the water would do nothing to lubricate the engine.