ECU Remap - worth it on a 535i (non-turbo)?

[e34.535i.sport]

Seems fairly rare - searched and found little on people getting their ECU's remapped professionally... The benefits they claim sound really impressive (211BHP - 231BHP and 320nm - 340nm torque and increase in MPG) for the price of £275 inc dyno runs to measure the increase.

Other sources suggest if your car is non-turbo the gains are not really that noticable...

Anyone have any info they can share or had this done?

[winfred]

a EAT chip knocked about a second off 0-60 on my old 90 535ia and returned about 1 mpg, i have the same chip in my m30b35 powered 81 633, gave a nice bump in power but i can't comment on mileage due to not having the speedo hooked up till after the chip was installed, hideously overloaded and in high winds i just got 24mpg on a long trip with it

[e34.535i.sport]

That is impressive, but my main concern with the EAT is fuel costs... Normal fuel is around 99.9p per litre here, and the V-power ect (higher octane) is at a ridiculous price.

I need to check with the re-mappers whether you need to use higher octane afterwards actually! Do that now before I forget!

[winfred]

you do need higher grade fuel as part of the power increase is from a more advanced timing, depending on the car and driver you can get some of the extra cost back in slightly increased mileage, around here it's about $3 more a tank for preimum and you usually get one or more mpg better

[Robin-535im]

I need to check with the re-mappers whether you need to use higher octane afterwards actually! Do that now before I forget!

I think you're right about that...

All people really do with the ECU mapping (custom or EAT) is to advance the timing... "All" I say, but to do it right is a whole career. Either way, there is a fuel mixture that is best for power, and our cars already hit that ratio when you floor it, so they are already pretty well tuned. The stock timing is set to allow the car to use lower octane fuel and hence the slightly reduced performance. If you advance the timing it will need higher octane fuel to avoid knocking.

I would imagine a custom tune up done right would net you more power than an off-the-shelf chip, as they can put you right at the limit for that particular car. You'll still need the better fuel though if you want to increase power as much as possible via timing advance. If you have someone local with a dyno who knows how to reprogram e34 ECUs, I would definitely recommend it if it's not to dear.

[e34.535i.sport]

I think you're right about that...

All people really do with the ECU mapping (custom or EAT) is to advance the timing... "All" I say, but to do it right is a whole career. Either way, there is a fuel mixture that is best for power, and our cars already hit that ratio when you floor it, so they are already pretty well tuned. The stock timing is set to allow the car to use lower octane fuel and hence the slightly reduced performance. If you advance the timing it will need higher octane fuel to avoid knocking.

I would imagine a custom tune up done right would net you more power than an off-the-shelf chip, as they can put you right at the limit for that particular car. You'll still need the better fuel though if you want to increase power as much as possible via timing advance. If you have someone local with a dyno who knows how to reprogram e34 ECUs, I would definitely recommend it if it's not to dear.

The firm I'm using has a Dyno and with before/after runs with an individual remap he charges £275. I've heard from a few sources that he has good results with BMW petrol engines and obviously with an m30 there is scope for improvement.

Your absolutely right, the factory naturally de-tunes the engines slightly on purpose for several reasons (people using poor quality fuel/missing services/etc) generally not looking after it. Therefore it can be improved... but as you say advanced timing will probably require a higher octane fuel. I'm wondering whether half premium and half 'normal' fuel would be ok?

[whiskychaser]

The firm I'm using has a Dyno and with before/after runs with an individual remap he charges £275. I've heard from a few sources that he has good results with BMW petrol engines and obviously with an m30 there is scope for improvement.

Your absolutely right, the factory naturally de-tunes the engines slightly on purpose for several reasons (people using poor quality fuel/missing services/etc) generally not looking after it. Therefore it can be improved... but as you say advanced timing will probably require a higher octane fuel. I'm wondering whether half premium and half 'normal' fuel would be ok?

If you use lower octane fuel isnt there a risk of pre-ignition? That blows holes in piston tops and valve faces. Not too good for gas flow and terminal if you let it go on too long. Certainly wouldnt do much for performance. Sure the tuning firm would tell you what's best. They may also have some comments on the quality of cheap supermarket fuel

[e34.535i.sport]

Too true! I never use the supermarket fuel, normally stick with Shell or BP if i'm stuck. I'm hoping to hear from them Monday as they're at a motorshow this weekend. I don't mind for example using 1/2 V-power and half standard Shell petrol, but full V-power would destroy me.

[genphreak]

Too true! I never use the supermarket fuel, normally stick with Shell or BP if i'm stuck. I'm hoping to hear from them Monday as they're at a motorshow this weekend. I don't mind for example using 1/2 V-power and half standard Shell petrol, but full V-power would destroy me.

If you want that extra 5% the best thing to do is build a www.megasquirt.info and tune it yourself for the fuel grades you want. Best thing to do it map it on std unleaded the first time, then go back to the Dyno with it running 100% high octane and map it for that.

Once you have these two settings, there isn't a petrol station that can upset ythe car, unless they have water, tolulene, methanol mix or whatever in their tanks... the megasquirt gives you endless options to do other things too-

[Qube]

Yes. I have to fill high octane now but it's so worth the drive...