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Steady state tuning

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When doing fuel table or ignition, load and rpm is independent from gear so if you map the car on 1st gear say or second then same map is used on gear 5 at 150mph same as 30mph

Is that fair statement? I am trying to see whether I do first or second gear for steady state and for full run you normally need 1:1 ratio, right?

For the most part, that should be correct - there may be small variations due to thermal/heat soak of components, less cooling airflow and, maybe any ram-air affect.

At the least, it will get you in the ball park.

A 1:1 gear, when possible, is usually used because the drive torque/power is direct from the input to the output, and there is minimal parasitic losses from the gear box.

There will be variance as load changes from gear changes. Tuning in one gear, then testing the other gears and tweaking as needed is suggested.

I generally use a gear shorter than 1:1 for the bulk of the tuning to reduce wear/tear on the engine, drivetrain, tires, and heat buildup. Yes the higher gear will usually show a higher dyno number, but you can do that "for the Gram" when you're near completion if you want.

I tried with first second, third and forth gear and got results i wanted. I used logging and mixture map and so far map is getting close to where I want it to be. Thanks for the advice.

I do think 4th gear is better at times when doing low RPM and don't want to be doing 10mph on the road so using 4th gear I can go faster whilst increasing load in low rpm


Sure, true load based on air flow, be that MAP/MAF are technically non gear dependent.

However, as pointed out above, the thermal load is very different. Single gear pulls on the dyno are not 3rd,4th,5th,6th gear flat out on track at somewhere like Castle Combe in the UK on the 5th lap of 20min stint.

IMO, you should map to MBT and pull back a couple degrees to give yourself a safety margin.

sure , if I understand correctly by thermal load you mean the higher the load in higher gears then temp will be higher in sustained full throttle?

I have left ignition table at default for now which is quite conservative and plan to put it on dyno to get mbt value and use knock sensors with good base so it can pull timing when it knocks. here is my ignition table which seems off to me.

I have the original BMW ignition table but it is based on maf and mg/stk and don't know a reliable way to convert and use them. see screenshot below.

from what I recall I need the pressure plus temp to calculate the map value and original bmw has maf which I guess uses this table plus iat to change the timing ? I appreciate if anyone can guide me on this as I could theoritically convert all values and use them here. car is stock



Correct, Ok, so looking at that. The engine is NA?

Unless you have significantly changed the compression ratio, like over 12.5:1 you should have a decent margin for error even on pump fuel.

You’re taking the right approach, by looking at the OEM IGN table and the being conservative and working up.

yep it is NA but soon turbo. I am struggling to convert the manufactor maf to map and hoping to find some formula as for instance don't know 125 mg/stk means what in map or mgp world

You don’t need to IMO.

They are 2 completely different measurements. 1 being inferred airflow - MAP and the other measured MAF.

Either that or relay on base map by link and go out driving it with det can and change the values to see when it will knock

i am doing road tuning so can't figure out mbt i guess

that is until i do dyno and get mbt properly tuned

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