E90 320i Tune

[DarrylvanNiekerk]

I have recently finished rebuilding my e90 320i engine and run it in, done about 3500km - car runs great.
I need to update my thread on this as I learned a lot and hit so many snags along the way - my first engine rebuild.

Resleaved, new rings, new bearings, new coil packs and sparks, sonically cleaned injectors, new exhaust valve guides and valve stem seals - 13 bar compression test.

I have a suspicion someone in the past played with the software but the car doesn't throw codes - my frame of reference is that the 6500 rev limiter has been removed.

I can either have the latest software replaced or add an aftermarket chip to confirm the car is running properly and at its best - probably both around the same price. The car does have a full branch CAT delete and free flow exhaust.

I have asked around and am considering taking the car to Dastek to have a Unichip done where they will tune the car on the dyno. Are there any other reputable suggestions that are Joburg based?

I know most would comment not to waste time or money on a NA 320i but after spending a lot of time and money on it I want to make sure it is performing optimally.

Thank you in advance.

 

[DarrylvanNiekerk]

I'm trying to do a bit more research before sending in for tuning. I drove down to Durban and back over the weekend and the power bump down at the coast was amazing.

I see the LCi 320i (N46NB20) engine has more power than the pre LCi (N46B20) and that is down to inlet manifold, exhaust cam and DME.

I spent some time today examining the parts and it looks like it's mostly just the throttle body that was changed on inlet side. The outer diameters of both throttle bodies are identical but the inner diameter on pre LCi is 61,5mm and inlet diameter on LCi is 65,5mm. The other difference is the plug connecter shape though they both have six connector pins so I assume signal would be the same.

Has anyone taken the time to put a later version throttle body onto a pre LCI 320i?

I'm intrigued to try this out as an additional 6,5% diameter should give better airflow.

 

[DarrylvanNiekerk]

Well I'm not sure which two throttle bodies I was originally given to check out but the pre LCI and LCI are actually very similar.

Anyway I had already decided I was going to give the process a whirl so I went ahead and bought a second hand N46nb20 throttle body and plug - you can't expect BMW not to design a new plug now can you.

It took a while to figure out the new wiring configuration but instead of wiring the new plug into the harness I decided to convert some spade connectors to fit into the old plug so I could test everything out without having to commit fully.

The diameter of the two bodies is almost exactly the same but the LCI is slightly shorter and uses a plastic butterfly but from 50 degrees the butterfly is fully open which the car reaches very quickly after starting up.

Although almost identical I have noticed a few changes already:

1. She used to idle at 840rpm but now she idles just under 800rpm.
2. On the freeway in 6th at 3000rpm or 123kph (up in Joburg) she would not have enough air to use more than about 12 litres per 100km and on steep hills would lose speed. Now I notice she is pushing up to 15 litres per 100km and can cruise up steep hills easily which negates the need to gear down to 5th.

Subtle changes but interesting nonetheless.

I might look at changing the inlet manifold as well to see if that further changes anything.

A little useless information.

 

[TurboLlew]

First time reading this thread. I am so amazed someone initially went to that trouble on a 320i. I guess you made lemonade from the lemons. That being said, at least your experience shared can help someone else looking to do these things/fiddle around with a 320i (even if it is a cautionary tale).

The amount of effort to get a car like this running right and then the constant fiddling as is needed by most modified cars vs. gain in power (and seemingly fuel consumption...) would lead me to sending it back to as-stock as possible rather than looking for other things to do.

15 litres per 100km cruising is beyond V8 M-Car fuel consumption Surely something is still amiss? Is that really what 320is get under those conditions

 

[Nick]

Lol my 320i was stock with a power flow system, worst Iv ever saw was 10l per 100, then a tazz passed me going up hill.

 

[DarrylvanNiekerk]

That consumption isn't truly indicative of what the car really is like as I average about 10 litres per 100km around town with some very spirited driving every so often.

Driving back from Durban I got just over 7 litres per 100km from start to finish through Joburg rush hour traffic at the end. What I was aiming to put across was the air flow is now better and it can thus increase fueling enough to maintain speed up a steep incline with the reduced air pressure up here - an almost 17% drop from the coast and without the humidity.

It will never be a great performer but there is enough low down torque that you don't have to wring its neck to get it to go and it handles hills quite nicely.

At the end of it all I have learned a huge amount and expanded my skill set more than I ever thought I would. Sometimes adversity brings about great challenges and learning opportunities.

 

[Solo Man]

Darryl, i applaud you man. Reminds me when i was young in the days of Anglias, Cortinas, Alfas, Gordinis, etc. With my Anglia bored to 1140cc, a nice cam, branch, freeflow and twin Nikkis. Maybe the sound it made was worth more than the little extra speed. I remember a friend had a then brand new Datsun 1200 four door and even with all my mods he would still outdrag me. But kudos to you man, spending all that money on your car getting it just right. Good luck and enjoy the car.

 

[DarrylvanNiekerk]

Darryl, i applaud you man. Reminds me when i was young in the days of Anglias, Cortinas, Alfas, Gordinis, etc. With my Anglia bored to 1140cc, a nice cam, branch, freeflow and twin Nikkis. Maybe the sound it made was worth more than the little extra speed. I remember a friend had a then brand new Datsun 1200 four door and even with all my mods he would still outdrag me. But kudos to you man, spending all that money on your car getting it just right. Good luck and enjoy the car.

Thank you very much for the support, it really means a lot.

It all happened during lockdown, I got into massive debt and had a lot of time on my hands. A few people have given me kak for rebuilding a 320 and spending so much money but it took me almost 2 years and I didn't have much choice - what else can I buy for R100k nowadays?
Now I have a reliable car that is fun to drive and I know how to look after it myself.

It has also opened up new opportunities where I am starting to rebuild cars for profit with the backing of an accountant who saw what I did with my car and wanted to do something on the side.

Follow the path and don't question, you never know where it is going to take you.

 

[Solo Man]

That is the spirit! If i was younger i would have liked to specialize in rebuilding certain engines that have common problems like the 2l BMW petrol motor with the valves problems as well as the 2l and 3l diesels with the chain problems. Also doing things like removal of egr's, swirl flaps, cats, etc., sort of specialize in certain areas. General service with minor repairs would also have been nice. Maybe diagnostics and fault finding with coding out stop/start, etc. Of course, would have invested in a two or four post lift for easy access.