Going 325i from 320i what will I miss?

[haffeel]

Hello Forumers,

I am changing my engine block from 320i to 325i. What other associated parts should I change precisely?

My mechanic says, other than the engine block, the rest all parts from my E30 320i will fit nicely. I kind of sceptical about the performance issue. I do intend to purchase a ZONE CHIP for 325i from ANT once my project car stabilizes.

Please list down all the items that I should watch out and the also if not changing together to 325i parts what performance degradation I will face?

thank you all

cheers

[TOURINGDADDY]

You'll need an ecu poss rad not to sure how diff they are oil cooler 4 the gear box the coding chip 4 the dash clocks

most of which i do have

[rowemeister]

The ECU is the same its just the chip thats different.

Rad will defo be different also the AFM I think.

[haffeel]

OK now the list is getting longer

1. ECU chip
2. Radiator
3. Oil cooler for the gear box
4. Coding chip for the Dash Board
5. AFM


Other please add. How many of you did the 325i conversion did use back the same old 320i parts?

[dazleeds]

discs for rear if you aint got em already lol

exhaust manifold as 320 has smaller ports but you can still use rest of 320i system if you need too

diff i think needs changing too

[TOURINGDADDY]

edit bump

[martinh]

Hope you've got plenty of money for insurance! My 320i Cab has been fitted with a stock 2.5 and costs nearly twice as much to insure as a standard 325 'cos it's modded.

I've also had problems with it over-fuelling on cold starts - if it doesn't start first time forget it! This is probably down to the ECU chip, so make sure you get the right one!

Good luck with the transplant

[Hammer1]

OK now the list is getting longer

1. ECU chip
2. Radiator
3. Oil cooler for the gear box
4. Coding chip for the Dash Board
5. AFM


Other please add. How many of you did the 325i conversion did use back the same old 320i parts?

Ive been there and done that conversion on my old 320i touring and i wouldnt expect it to be much different from a saloon.

As the other guys said..ECU,AFM plus bellows,inlet manifold+tbody,oil cooler,ex manifold (320i touring not needed)and rad if you want,i never changed mine and never noticed any extra temp increase.All the other 320i bits fit and it is pretty much plug and play.

BTW you can use your original gearbox,clutch (i personally would use the uprated 325i clutch) and diff if you want,its the cheapskate way and works ok but youll find it revs up quicker (depends on the diff ratio youve got?) but loses the top end.

[rowemeister]

the engine should run ok on the 320i chip, you said you were going to get a zone chip so buy that and stick it in the ecu

[jonb]

haffeel


when you say block do you mean just the bottom end??

if so then the 2 litre head wont work.....

if its the 2.5 bottom end and the head then you need to source loadssss of other parts as meantioned above.

if so then dont tell your insurance. the engine looks almost the same.

[haffeel]

Hi thanks for so many replies.

The engine means, the complete block, top and bottom as one lump.
Yes, I will be changing the differential from 4.45 to 3.72

The gear box is auto which I reacently installed from a second hand shop.

Yes, I will put a ZONE CHIP,

reading all the reply here, what I worry is , the manifold which I understand has smaller opening than 325i and also the radiator which might prove not enough.

So how much BHP I will loose with this setup?

I mean, not changing the manifold, AFM and Throttle Body.


cheers

[Andy325i]

I have a few 325i Ecu's lying about and think I may have a 325i manifold as well, if you need either just give me a shout

Andy

[haffeel]

I took a vernier caliper and checked the exhaust manifold port hole and the engine exahust port hole, they are both same size.

I cant say the same for the inlet, it is about 3mm short total from the radius. I suppose I can live with that.

what is the rational in changing the gear oil cooler?

Andy and the rest willing to help me with parts, I will pm you guys if I need them.

thank you all

[haffeel]

Touringdaddy,

what is this for

"coding chip 4 the dash clocks

[TOURINGDADDY]

so ur speedo knows u got a 2.5 and gives u the correct speed/mpg

[Brianmoooore]

so ur speedo knows u got a 2.5 and gives u the correct speed/mpg

Won't make a lot of difference if you use the 320 one, since they are both 6 pots.

[haffeel]

Hi BrianMoore, Sure mate,

My ex is a 320i 6 pot, that means no need to change the chip .. Goooood

[jmc330i]

The radiator with transmission cooler is the same between 320i auto and 325i auto. So theres no need to change that.

[Brianmoooore]

Who said this car was an auto?

[jmc330i]

Who said this car was an auto?

The gear box is auto which I reacently installed from a second hand shop.

And the 320i manual and 325i manual rads are the same as well.

[haffeel]

jmc330i good observation. Yes my ex is an auto 320i

looks like then lot of my worries are for nothing. I can rest easy knowing all is well.

Thanks for all the nice people here. In just 24 hours, I got all my answers which I doubt very much can accomplish even going to 10 different mechanics.

[rickk]

The injectors are different too. Change them or the car will run really lean at the top end, quite likely damaging things severely in the long run.
FPR is different too, 3.0 bar vs. 2.5. Running on a 2.5 will cause a very lean condition between sth. like 4-5k rpm and a noticable hesitation in that rev range in 2nd and 3th gear.

Also, I'd seriously consider fitting a 325i intake manifold while your at it, it's not like they're THAT expensive and it would suck having to put it on later. Same goes for TB (it's different).

Spark plugs are different too IIRC.
Gauge cluster coding chip should be fine as-is. Same goes for OBC (if you have one).

- Rick

[haffeel]

Phew !




Thanks for the feedback !

appreciate M8 !!!