E90 323i Conversion to 325i

[Andy1GP]

@ Damon1 very informative post. IMO cost doesn't justify the means.

I also agree 100% with the post below.

You can train a racehorse to run faster but a donkey stays a donkey.
:biglol:
The biggest mistake most people make is starting with the wrong pedigree. :idea:

 

[Nikhil]

It's the exact same as the e46. The 323i and the 325i both had 2.5 litre engines. 323i was released in 1999 alongside the 328i. The 323i was meant to look like it had a massive power gap between the then 2.8 litre 328i. This was to help drive sales for the 328i.

2002 saw the intro of the 325i, which had 20kw more. It too was a 2.5 litre double vanos engine, but had bigger intake and software. It took over from the 323i which stopped production in 2003. The 330i also entered service in 2002 and replaced the 328i.

The 323i had the M52Tub25 whilst the 325i had the M54b25.

The Tub stands for Technical Upgrade. The M52tub25 was the latest version of the e36 engine which had double vanos. It was used in the e46 323i before being replaced by the M54 in the 325i.

Changing the intake and software as well as bigger injectors would see the 323i power levels raise... but why not just supercharge the damn thing. =D

+1 same with the E36 323i and 325i

 

[tman]

Hi All-

Ok lets start by saying that i had the displeasure of owning two E90 323i ( 130Kw/2006 and the 140Kw/2007).And yes back then i was enthusiastic enough to want to do the same conversion.Almost all the companies i phoned were not familiar with the power difference and only one "Upsolute" claimed that they could convert the car to 325i power.

So off i went cash in hand to have the conversion done.They removed the ECU,read the file,sent it to Germany,UK or the moon to have it reprogrammed.Had the ECU installed and was promised 160Kw.Drove the car for a week and could not tell the difference.I then took the car to BOSCH to have it dyno tested and lo and behold the car was 3KW faster.Yes,you read right-just 3Kw-The moral of the Upsolute story is clear.Unless they reprogram and DYNO test your car in front of you,DONT trust their WORD.Oh and it was a mission to get back my refund.SOmetimes the mind belives ur going faster after someone "interferes" with the ECU.

OK now to the differences.THe E323i is unique to JAPAN,CANADA and u guessed it S.Africa.

The differences as as ffg.
1. Different ECU mapping - BTW - 325i has a higher RPM cut off as well(6500 vs 7000)
2. 325i two stage DISA intake manifold vs 323i single stage DISA
3. Intake manifold is smaller/narrower on the 323i than on the 325i.

Now while u may say that just by progamming the ECU u will get the power-Answer is NO- A 323i will run with a 325 till 90Kph-beyond that the extra breathing and mapping on the 325 will make it pull away-believe me i have tried and tested.Your best alternative to live with the 323i is to install a K&N as i did back in the day.It breathes alot better and wont crash your feelings when 4cylinder cars want to race you.

So in the interest of saving my sanity i have reverted to buying a E90 320d(130Kw) with a chip(170Kw/450nm)- It runs neck on neck with a E90 330i on the freeway and pulls away from it at the robot.I dont even race a 325i cos they dont keep up-The results of chipped diesels are just amazing.I have outran golf 5 GTI's that are chipped as well.
Hope this helps and saves you guys alot of painful searching from tuners who need to pasture in a 4x2 bull pen and for once stand in the same stench of "bullshit" that they pass off.

What an informative post! Rep+

 

[tcal69]

Is BMW becoming the new VW, all you need is a cone filter:roflol:

:sorry:

 

[realtrevor]

Is BMW becoming the new VW, all you need is a cone filter:roflol:

:sorry:

It would seem so.

 

[gahamed]

Hi All , I have been reading this thread lately and I find it strange , yet funny that when someone ask the question on modifying the 323 to achieve 325 "power" the bottom line of this conversation is ... buy a 325 , yet the owners of 325 are modifying their cars. the question here is then " did the 325 owners then want a 330 perhaps and the 330 guys a M3 perhaps?
I am sure there are many a 323 owner out there that is not even interested in modifying his car and who is very happy with his choice of car.
Sometimes it is not what your car feels like , but how YOU feel like when you drive the car...please people do not discourage the potential buyers of 323 to go for bigger & better.. Lets all remember why we bought our BMW's for in the first place.... PURE DRIVING PLEASURE....

 

[akash]

Hi All , I have been reading this thread lately and I find it strange , yet funny that when someone ask the question on modifying the 323 to achieve 325 "power" the bottom line of this conversation is ... buy a 325 , yet the owners of 325 are modifying their cars. the question here is then " did the 325 owners then want a 330 perhaps and the 330 guys a M3 perhaps?
I am sure there are many a 323 owner out there that is not even interested in modifying his car and who is very happy with his choice of car.
Sometimes it is not what your car feels like , but how YOU feel like when you drive the car...please people do not discourage the potential buyers of 323 to go for bigger & better.. Lets all remember why we bought our BMW's for in the first place.... PURE DRIVING PLEASURE....

So let me give you my experience, simply because i am a perfect example to this scenario.

My first BMW was an e90 323I. I LOVE the car. They have bullet proof engines and served my needs "at the time". However like most 323i owners who had already owned the car, i wanted more and trust me, the cars performance in terms of power has a lot to do with how YOU feel when driving the car. I came from driving a 1.6l to a 2.5l so i am familiar to this.


Then the bug bit like with a lot of 323i owners and the same can be said for a lot of other car owners, I WANTED MORE POWER.:rollsmile:

However the cost vs power gained did not make any sense what so ever even though the 323 and 325 had the same engine. With that additional money i would have spent i could have bought a 325i in the first place. The best advice came from this forum, upgrade to a 325 or higher and they were right.

I went out and got a 335i, but guess what the bug bit again and in went a JB4, DP's etc into the 335i.

Morale of the story, if a had done my research before buying the 323i, i would have accepted the 323i for what it was and is, not a performance car, but a daily runner that is bullet proof and i would have been happy with that.

To your comment above, are 325i owners trying to get 330i power, the answer is No. Simply because in that situation the engines are different in displacement, same answer to your 330i guys looking for M3 power, different engines.

 

[Kaaba]

Well said

 

[Trevino27]

Thanks damon1, i guess i wont persue that money waisting conversion.
Stock 323i FTW :mmm:

Really good advice given. With a 323i and a few mods that won't break the bank and u can really get a substantial amount of power. Simple K&N filter... dekat and full stainless steel exhaust system.. stainless steel branches and short ram air intake forced induction. And trust me you will forget about owning a 325i and if u have the Bucks and feel adventurous why not a plug and play chip or ecu remap. Take this from a guy who owns a 320i E90 with the above. Puts a huge smile on my face everyone I drive it. I know it will never be as quick as a 6 cylinder 330i - but it depends on u at the end of the day... ur car... ur life.... ur daily drive I think about having those extra 2 cylinders and the difference it would make save that for my next 335i e93

 

[sclass]

I have no illusions about my car, it’s a bottom of the range ‘6’ with loooooong ass gearing and highish curb weight. It cannot be tuned/modded for jaw dropping performance without resorting to extreme (costly!) methods. So if I were to do any mods it would be to improve breathing and fuel consumption (BM has a performance intake and performance exhaust for eg.) and then maybe put a tune to optimise those changes. Won’t turn it into a fire breather, but if it is a bit more responsive, a bit better on fuel, sounds nicer, then I’m sure I’d enjoy the car a whole lot more! Whether the cost for the gain is justified, well probably not. Also we do have to be worried about the dubious claims of some tuners. But surely a GENUINE 10-12kw gain from exhaust/intake/tune isn’t unreaasonble is it lol? However there are people who have spent R15k on a 19” wheel/tyre combo on a 320/323/325 which actually slows the car down and has no handling benefit, and yet are perfectly happy!

Not always feasible to just swap to the next higher variant for better performance unfortunately, especially if you are still paying off vehicle finance. On the bright side though n52 in low output guise is bullet proof, mine is currently on 220k, no smoke and doesn’t eat oil, only issue has been a blown FRM (footwell module). I can live with that :rollsmile:

 

[individj]

if you have a 323i & you get the 25i parts for cheap it makes sense to do this.

 

[kilotango]

honestly, the best way sometimes to get better performance and economy is to simply remove the 3x 21" subwoofers in the boot, the 4 amplifiers and capacitors... and generally keep the fat people out of your car. :tiptoe:

i once diced with a dude in a e90 325i full of M badges and stickers of all the mods he had done on it, with my plain jane standard jetta mk4 1.9 tdi and wiped the floor with him.. just because of the all the junk he had in that car.

performance is relative sometimes, as crewzer mentioned. personally, i've left my 330 alone in the performance dept, as when i need to overtake someone, it goes like hell when i put my foot down. thats good enough for me

90% of the time, when a dick pulls up to next me in a GTi at the robots, i usually still can leave him far behind.. and with none of that turbo whoosh whoosh dump valve BS

 

[gahamed]

I agree with every one on the modification side on the 323i , if you really want more power, do the upgrade to 325i and so on , because if power was the objective of the purchase of such a fine car then you don't have a choice, maybe the guys thought buying a "watered down version" of the 325i is cheaper " and then I can add some mods to it.
My concern is where guys refer to 323i as "donkeys" and the impression that it is an inferior vehicle when it comes to power , it has plenty if it is used properly if this was such a "dud" why was it built in the first place , I still maintain that most people still believe that bigger is better and more "power" is superior.
We will always strive for more power and forget why we actually bought our cars in the first place.

I am all for this statement "performance is relative sometimes, as crewzer mentioned. personally, i've left my 330 alone in the performance dept, as when i need to overtake someone, it goes like hell when i put my foot down. thats good enough for me"

 

[Garethe90]

Just got here guys i got a 323i sport lol . Love the car just feels right but.. performance nerd more obviously and i want to supercharge any ideas on where to start and at reasonable prices.

 

[Juggy]

You can train a racehorse to run faster but a donkey stays a donkey.
:biglol:
The biggest mistake most people make is starting with the wrong pedigree. :idea:

Yeah, like a BMW

 

[akash]

Just got here guys i got a 323i sport lol . Love the car just feels right but.. performance nerd more obviously and i want to supercharge any ideas on where to start and at reasonable prices.

Word of advice...... leave the car as is or trade in for a 335i.