m52tub20 NA tuning racecar track

[TobyB]

Huh. It might just be coincidence, but did you notice that you have torque bumps where your a/f goes to about 12.8, and directly correlated dips where it drops to 12.4,
or goes over 13:1?

I've found that my car (M10, so very different combustion chamber) responds similarly- if I have the testicular fortitude to run it at 13:1, I make best power and I don't
get any appreciable detonation. I use carbs, so I tend to play a little safe.

John and Digger will have more insight, but while my first thought was intake resonance, that a/f correspondence is very direct. Personally, I'd mess with it to see...

t
would also be tuning his own DME.

[varg]

Yeah hopefully you can clean up the fueling because that AFR is all over the place, you should pick up some torque and smooth the curve a lot, maybe gain a few hp. It is very difficult to make any meaningful difference with the tune if the AFR isn't holding steady within a couple of tenths. I'm curious about why you did the dyno runs in 3rd, avoiding a speed limiter? It doesn't make much difference on dynapak because you can use the hold mode to set gear ratio by matching the tach/tuning software rpm with what the dynapak software reads, but even on the chassis dyno I always see/do the runs done as close to 1:1 as is practical.

[Norwegenbmw]

Yeah hopefully you can clean up the fueling because that AFR is all over the place, you should pick up some torque and smooth the curve a lot, maybe gain a few hp. It is very difficult to make any meaningful difference with the tune if the AFR isn't holding steady within a couple of tenths. I'm curious about why you did the dyno runs in 3rd, avoiding a speed limiter? It doesn't make much difference on dynapak because you can use the hold mode to set gear ratio by matching the tach/tuning software rpm with what the dynapak software reads, but even on the chassis dyno I always see/do the runs done as close to 1:1 as is practical.

It was my first time performing a dyno test and i didnt know all the details of how it was done until we got there. The "dyno man" was assuming my 3rd gear was 1:1 and also asked for my differential ratio, he typed this in on the computer and the reading was off.
So he calculated the difference between the diff ratio and another value? and we got the correct reading.
The next time we go on the dyno we will use the 5th gear for sure.
The first dyno pull we did was with the maf sensor plugged in and i got around 132whp, and then without maf plugged in we got the result i showed you here 137,8.
Unfortunately i didnt get a photo of the first pull.

[TobyB]

Ah- the unplugged MAF may explain some things, as the DME was defaulting to a table.,
assuming a stock engine and intake.
The MAF SHOULD be your friend, as you tune, so in your place, I'd try to figure out how to get
it to work with you, not against you.

4th gear is 1:1 with an E30 260 gearbox, but 5th is 1:1 for the E36 and later gearboxes, even the 6- speeds.

t

[Norwegenbmw]

Hi.
I recieved a new chip tune with some updates for more fuel after 6000rpm and also changed the rev limiter to 7200rpm.

As you see in the results i got a decrease in power. (137whp to 132whp)
This was done with the maf plugged in.
I found out after the dyno session that my DISA valve was not working.
Can this be the reason for my low fuel after 6000rpm issue?
Both on the first dyno run and this one.

On this dyno session i also changed back to the first original chip and got the same amount of power as the first dyno, (summer 2022).

What do you guys think?
i want to gather information to be certain that the DISA is my problem before going to another dyno session.

[Norwegenbmw]

Hi.

I drove this years first event the 5th may with total of 84 laps / 294 kilometers on the track "vålerbanen".
Best achievement of the event was a 12th place on qualifying with a total of 34 cars, but went further down in placements on the actual races. 18th-14th-23rd place.
There is still allot of room for improvement.

I drove my first two practice laps with the MAF sensor plugged in but from the third practice and the rest of the event i drove with it un-plugged, and noticed a bump in performance.
My car accelerated somewhat faster than my friends VW polo 146whp 960kg car on the straights.
And my friends Opel astra with 160whp 1080kg would barely pull away from me. (My car is around 970kg).

This is only what i think because i dont have real measurements but it seemes by plugging in the DISA valve it has helped and maby given me more whp than the ~138whp measued on the dyno.

I wont spend more time and money putting the car on the dyno again because i am planning to do a new spare engine build and eventually replacing it in the car.

Will build a m52b20 with:
m50b20 intake manifold
full exhaust and headers
m54b30 intake cam
m50b20nv intake cam on exhaust side
Do some light porting work
maxxecu engine management