318is - > 2.5 conversion

Discuss general engine, turbo and supercharger conversions in this section

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Conrad
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Post Sun Mar 11, 2007 10:17 pm

Hi guys

I know this has probably been asked before, but a quick search hasn't found me the info I wanted.

The previous owner of my vehicle mentioned that it has the same struts etc as the 325i sport, is this true?

What parts would I have to replace to lump in a 325i engine and box in my 318is?
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Brianmoooore
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Post Sun Mar 11, 2007 11:55 pm

Very similar suspension/brakes etc. to a 325i, except that front springs on a 318iS are weaker for the lighter engine.
You'd need to change engine, box, radiator, engine loom and ECU, propshaft and diff, and a few welded brackets in the engine bay.
If the iS engine is OK, I wouldn't really recommend this conversion. The iS is slower than a 325, but not by much in the real world. What it lacks in grunt, it makes up for in handling.
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Post Mon Mar 12, 2007 12:02 am

And the boys would come round and kick your head in for murdering another iS.
...or is it?
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Conrad
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Post Mon Mar 12, 2007 8:10 am

the iS engine is OK, but it lacks low down torque. Perhaps I'll be happier if I get a zone chip.

The problem as far as I can see, is theres very little you can actually do to tune an M42 without spending silly money, and that money would probably be better off spent on a 2.5i engine...
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keggy
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Post Mon Mar 12, 2007 8:22 am

chip and big bore throttle body will help
stuartgallafant
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Post Mon Mar 12, 2007 8:30 am

Omi wrote:And the boys would come round and kick your head in for murdering another iS.
yeah, im with omi on this...

conrad, kos spent less than £300 on engine mods for his iS, and it would keep up with 2.5's all day long

the M42 is a much better engine than the M20, and is lightyears ahead of it tech wise.

dont murder another iS, just to be on the desperate hunt for a little bit of low down torque. spend a good bit of cash on the iS and you'll be well happy

and as brian said, they handle a lot better than the 2.5's
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Conrad
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Post Mon Mar 12, 2007 9:45 am

stuartgallafant wrote:
Omi wrote:And the boys would come round and kick your head in for murdering another iS.
yeah, im with omi on this...

conrad, kos spent less than £300 on engine mods for his iS, and it would keep up with 2.5's all day long

the M42 is a much better engine than the M20, and is lightyears ahead of it tech wise.

dont murder another iS, just to be on the desperate hunt for a little bit of low down torque. spend a good bit of cash on the iS and you'll be well happy

and as brian said, they handle a lot better than the 2.5's
What you're saying does make sense, could you expand on what mod's Kos did to his? I'd quite happily spend £300 to keep up with 2.5's.

Cheers,

Con
m-dtech
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Post Mon Mar 12, 2007 10:00 am

if you do decide to do an engine conversion, stick in an s14 :)
oldroydsr4
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Post Wed Mar 14, 2007 6:37 pm

I believe lightening the flywheel makes a huge difference on the m42
stuartgallafant
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Post Thu Mar 15, 2007 11:17 am

kos iS:

-removed throttle body heater plate
-K&N panel filter - NOT A GAY CONE FILTER!!
-live rolling road remap

thing was wicked!! and well good on fuel too!!

he might of had a big bore throttle body too, but im not sure
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jonb
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Post Thu Mar 15, 2007 11:53 am

Kos's car did not trouble 325i's.

I proved that on the way back from ace last year.
stuartgallafant
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Post Thu Mar 15, 2007 11:58 am

yeah, sorry, im making it up...
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jonb
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Post Thu Mar 15, 2007 12:01 pm

Yes you are. :)
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Post Thu Mar 15, 2007 2:46 pm

A 2.5 will always be 20 bhp ahead of a 318iS (136 bhp v 171) - so how will a 318iS 'keep up'?? Even if you dragged 150 bhp out of it, you're still way behind.

Not on your nelly.
stuartgallafant
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Post Thu Mar 15, 2007 2:52 pm

a standard iS will of course be behind, i agree. but we're not talking about standard iS's are we mr everett...
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jonb
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Post Thu Mar 15, 2007 3:59 pm

A chip, "zorst", and filter wont make hardly any difference.

Even so, my standard 325i 4 door which i was driving at the time, shat over kos.

The 318is is an ok car, good round the corners to, but it will never be a 325i on the straights.
Morat
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Post Thu Mar 15, 2007 5:10 pm

Whats this we have here? another 4V6 thread?
Shurley shome mishtake?
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Royalratch
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Post Sat Apr 07, 2007 11:50 pm

This swap makes no sense at all.
The iS is more than just a modern twin-cam 4 pot E30. It's really balanced and the best package of all.

Get a chip, exhaust and K&N filter and maybe a diff change / flywheel change. Supercharge it.

Anything but a swap.

318iS would easily keep up with a 325i with very few mods.