1M stock vs JB4 stage 3 power

[T1M]

Im trying to work out what the relative gains are on a 1M when moving from stock to a JB4. Marketing material typically uses 135i or 335i stock figures and ADVAN performance shows a jb4 equipped 335i putting down 248wkw. They use tractive effort for torque so no idea how this translates to nm. Anyone know what a stock 1M puts down or have any dyno graphs after installing a JB4?

[BMWhoarder]

1M uses the same engine and (roughly) the same stock tune apart from the the M button for temporary overboost.

Expect roughly the same results from a 1M with JB4 as any other n54 engine

[vtl]

Hard to say but after a JB4 the power should be roughly the same since the boost targets should be the same. Exact final power will depend on a bunch of things such as the intake/exhaust/downpipes fitted and also whether walnut blasting had been done.

The 1M already has high flow downpipes so that's another thing to consider

[Zuzu]

Originally Posted by einserM

Im trying to work out what the relative gains are on a 1M when moving from stock to a JB4. Marketing material typically uses 135i or 335i stock figures and ADVAN performance shows a jb4 equipped 335i putting down 248wkw. They use tractive effort for torque so no idea how this translates to nm. Anyone know what a stock 1M puts down or have any dyno graphs after installing a JB4?

Off hand mine had 239.5wkw stock on the Advan Dyno..
If I can find the graph I will post.

On this particular day, Pete dynoed 3 stock 1M's and they varied between 232 and 239.5wkw.
Hope that helps..

[T1M]

232-240wkw is quite surprising, that'd put a 1M around 280-290kw at the engine. So on a 1M basically the only use for a JB4 is tuning it with E85 or larger turbos.

[flinchy]

240wkw is about what you'd make on 14psi... which incidentally is what the 1M runs at least in overboost iirc. It's also what the 'stage 1' tunes target.

can still turn the boost up even more with the JB4.

[T1M]

It feels about 230-240wkw, but the torque and smoother delivery of the power vs 2L 4 cylinders I've had in the past threw off my butt-dyno calibration

[martymil]

Originally Posted by einserM

Im trying to work out what the relative gains are on a 1M when moving from stock to a JB4. Marketing material typically uses 135i or 335i stock figures and ADVAN performance shows a jb4 equipped 335i putting down 248wkw. They use tractive effort for torque so no idea how this translates to nm. Anyone know what a stock 1M puts down or have any dyno graphs after installing a JB4?

I've put a jb4 on my 1M and although I felt an increase on map 5, it was disappointing, then I added 7 litres of e85 into the tank and topped it off with 98, wow what a difference.

It really transformed the car from a kitten to a lion.

The problem with our cars is 98 ron fuel, ITS CRAP.
Where the timing on 98 was utter rubbish and was getting pulled left right and center, adding e85 has stopped all that.

Once you add a little E85 into the tank the jb4 really shows its legs.

[dh58]

I agree with Marty, I've been focused on it recently and its right. The ron98 we're paying for is bullshit.

[T1M]

Marty is your 'map 5' just the stock auto-tune map with stock ECU tune? Is the top log 98 and the lower with E85 added?

Do you run a wideband(s) and if so what AFR is it running under load with 7L E85 in the tank do you know - looks mega lean from the logs, almost 20 AFR under full load down low and doesn't drop <15 until ~3000rpm - if that's correct I'm surprised you're not getting lean breakup. It does look to drop to ~12.5 from ~3000 on though

7L of E85 topped off at 53L gives you 11.22% Ethanol and should raise the octane enough to quell any knock, probably around the 100 octane level there with Vpower or Ultimate as the 98 compnent. Agree with our 98 being not so good, it's equivalent to about US 92 octane from my experience tuning Evo's.

[martymil]

the first run was terrible on 98 look at the timing pulll
Second run was with 10 % e85 content as e85 is really e79 at the bowser

The afr's are pretty good for stock as the are quite lean from factory

Actually the afr's are better with e85

[martymil]

It quells timing knock but still pulls timing out even with 10% e85
If you don't want to get any timing pulls or knock you need to convert to straight e85
like on my 135 but that's another monster

[T1M]

Wow the stock timing map must be pretty aggressive to pull timing even with ~10% ethanol.

With low and high pressure fuel pump upgrades is it possible to run straight E85 on stock turbos or do you absolutely need port injection?

[martymil]

You need at least a stage 2 lpfp and a fuel it tbi but that's a pretty crude system

Pi is the way to go but at 3x the price

[T1M]

What, like 3,5K or so all up? That's not bad for the capacity to make ~300wkw and run straight E85. Plus with fuel washing down the valves and ports think of all the money saved on walnut blasting!

[martymil]

More like 4K with a custom back end flash and dyno time
Plus 1300 dollars plus labour for a stage 3 lpfp and wiring is a bit
of a biatch so allow at least 2 to 3 hours for that

Not so good is it, hits you right in the pocket

but the problem with both systems is you can't run a stock air box
and that kills it for me


..

[T1M]

A ffs. No stock airbox? I want to retain mine too.

[dh58]

I thought you could but with modification? (At least on tbi)

[BMWhoarder]

Originally Posted by einserM

What, like 3,5K or so all up? That's not bad for the capacity to make ~300wkw and run straight E85. Plus with fuel washing down the valves and ports think of all the money saved on walnut blasting!

i made 290kw with TBI on straight e85 and smoked turbos. Set your heights a little higher

[martymil]

300rwk is the minimum you will get with pi.

Where you will see massive gains is down low and midrange torque

It's the inlets that are holding us back

[dh58]

Marty is there really a difference in power between pi and tbi? Say on stock turbos?

[martymil]

I don't know about tbi but with the Pi the the torque lift is huge down low