[SMD001]

Haven’t done much with z4 but drive it do to finishing a corvette build. Local shop had a dyno day for “Supra’s” so I went. They specialize in BMW.

Had them put the JB4 on before testing. It was set at tune 1 for all runs. MTS intake and JB4 only mods.

Pleased with results: 436whp and 469wtq. 1st run was the best as heat was oppressive (Georgia US.)

Looking forward to going back to the track this fall.

[Balr14]

I don't know the JB4 well, but isn't stage 1 nothing but a small boost increase?

[SMD001]

Originally Posted by Balr14

I don't know the JB4 well, but isn't stage 1 nothing but a small boost increase?

Yes. 2lbs
It’s capable of more with proper supporting mods, fuel etc.

[BEAR-AvHistory]

What brand dyno was it run on? Would be interested in a Dragy run if you have one.

[SpeedyATL]

Don't suppose you have a "before" run as well? I suspect you would have posted it if you did.

From a quick Google search, looks like JB4 is good for about 40hp on the lowest map (not sure about the intake).. So that would imply your car is somewhere about 390hp at the wheel stock or about 440-450hp at the crank if my math is correct.

Very impressive no matter how you slice it...

[ebirotedu]

15% drivetrain loss estimate is probably on the high side.

Originally Posted by SpeedyATL

Don't suppose you have a "before" run as well? I suspect you would have posted it if you did.

From a quick Google search, looks like JB4 is good for about 40hp on the lowest map (not sure about the intake).. So that would imply your car is somewhere about 390hp at the wheel stock or about 440-450hp at the crank if my math is correct.

Very impressive no matter how you slice it...

[SpeedyATL]

I think i used 12% loss, which is about what dinan uses on their site for a '20 M340i.

390 ÷ .88 is 443hp.

Did i back into it incorrectly?

Dinan shows 393whp for their stock 2020 m340i....and 448 estimated crank hp.

https://www.dinancars.com/products/s.../D900-B58-G-S1

[ebirotedu]

No, your math is right. I ballparked it in my head going the other way.

The base 390 hp peak number threw me off. That dyno might read high assuming the 40hp peak increase is accurate.

10-12% loss seems about right.

Originally Posted by SpeedyATL

I think i used 12% loss, which is about what dinan uses on their site for a '20 M340i.

390 ÷ .88 is 443hp.

Did i back into it incorrectly?

Dinan shows 393whp for their stock 2020 m340i....

https://www.dinancars.com/products/s.../D900-B58-G-S1

[Balr14]

I have a friend with a 2021 M340i. (Seeing what that car can do was a huge incentive for me to buy a Z4 M40i). He likes to mod his cars and it doesn't matter what kind of vehicle it is or much it costs. His M340i dynoed 401hp in stock form, with 8k miles.

[stlcdr]

40hp with the JB4? Isn't that a piggyback tuner (just plug it in)?
Sounds like a lot, to me, but looks like it's true based on those dyno numbers.

[SMD001]

Originally Posted by BEAR-AvHistory

What brand dyno was it run on? Would be interested in a Dragy run if you have one.

Dynocom awd 5000fx.
Have a draggy but don’t card for it. I prefer actual track times.

[SMD001]

Originally Posted by SpeedyATL

Don't suppose you have a "before" run as well? I suspect you would have posted it if you did.

From a quick Google search, looks like JB4 is good for about 40hp on the lowest map (not sure about the intake).. So that would imply your car is somewhere about 390hp at the wheel stock or about 440-450hp at the crank if my math is correct.

Very impressive no matter how you slice it...

No before. Would have liked too but not enough time. If you calculate the Gp using the ET it ran last fall (12.40 @ 118) that has the math at 404. I think the 390whp is probably accurate for stock. On a mustang dyno I’d expect it to be 10-15% less based on the different types of systems.

The JB4 looks to be accurate for claimed gains. I may try the second tune which is still 93 octane safe when I go to the track this fall.

[SMD001]

Originally Posted by stlcdr

40hp with the JB4? Isn't that a piggyback tuner (just plug it in)?
Sounds like a lot, to me, but looks like it's true based on those dyno numbers.

Simply plug in multiple connections. Has several “can” tunes and the shop was adamant that I do not go past tune 2 unless testing the fuel and data logging. Apparently they have seen multiple folks cause catastrophic damage.
If this snowballs and I decide to keep going I will get the ecu cracked and go boostmod. Then a proper tune. This is simply a. Easy way to add a few HP and reverse the mods if needed.

Bottom line, everyone knows BMW for what ever reason sandbags on the numbers. As does Porsche and some others.

[BEAR-AvHistory]

Originally Posted by SMD001

Dynocom awd 5000fx.
Have a draggy but don’t card for it. I prefer actual track times.

Have found Dragy & track clocks close enough for government work. Dragy runs at a track will pretty much match-up with the track clocks.

Street Dragy and Dragy track will vary with the plain street surface showing slower numbers than the prepared track surface.

90% of these cars will never see a drag strip so the street number has value to more people running street fuel. Track fuel mixes tend to be much more aggressive. That's why the JB-4 can hold a number of different MAPS

FWIW when I was beta testing JB4's for BMS most of my logs and the group I was testing with were created on the street. We did the logs & BMS made the changes. Various maps were created straight pump octane 91/93/100 as well as various pump octanes mixed with E85. The full out race gas maps were generally made with track data.

[SMD001]

Originally Posted by BEAR-AvHistory

Have found Dragy & track clocks close enough for government work. Dragy runs at a track will pretty much match-up with the track clocks.

Street Dragy and Dragy track will vary with the plain street surface showing slower numbers than the prepared track surface.

90% of these cars will never see a drag strip so the street number has value to more people running street fuel. Track fuel mixes tend to be much more aggressive. That's why the JB-4 can hold a number of different MAPS

FWIW when I was beta testing JB4's for BMS most of my logs and the group I was testing with were created on the street. We did the logs & BMS made the changes. Various maps were created straight pump octane 91/93/100 as well as various pump octanes mixed with E85. The full out race gas maps were generally made with track data.

I may dig the draggy out and try it. I won’t be running anything but 93. I know that leaves power on the table but I have other cars with more power anyway.
Agree with prepped surface but with our local track it’s a crap shoot how well it it hooks. On a very well prepped 1/8 mile I went 7:80 on the original super sports.

[MisanoblueZ4]

These dyno numbers are stronger then my former stock 2006 Z06 (505hp rated), hp about the same but this Z4 M40i with couple mods put out more torque.

Wonder if the OP is still here and went back to the track with this car.