What do people mean when they say the Jb4 "isn't smooth"

[JoeyBananas]

Might be a dumb question but I keep reading threads or posts when people discuss a flash vs piggyback etc and I have read a few people say the Flash tunes are "smoother".

I'm going to hook up the fuel mass connector but even so, will there be hesitation, stuttering etc that can be expected as the norm?

Thanks

[GMWNashville]

its an If this then that system...and IMO it reacts much slower than a flash tune.

[JoeyBananas]

Originally Posted by GMWNashville

its an If this then that system...and IMO it reacts much slower than a flash tune.

That's aggravating, thanks.

MAP4 is the "OEM PERFORMANCE" and diagnostics only, is the JB4 controlling boost, timing etc but only producing stock boost, or is it pretty "hands off" and it should be smooth like OEM?

[GMWNashville]

Under normal operating conditions the jb4 works ok...it just isn't perfect. That's my biggest complaint...

[JoeyBananas]

Ok thanks, but for MAP4 is the JB4 "intercepting" signals and telling ECU what to do or is the JB4 completely out of the equation with the exception of diagnostics (clearing CEL etc)

[ShlemonboostedM]

It's completely fine .. It drives fine and smooth .. I personally can't tell the difference in smoothness.. Stock vs jb4 map 1

[Mike@N54Tuning.com]

Originally Posted by GMWNashville

its an If this then that system...and IMO it reacts much slower than a flash tune.

Simply not the case. The JB4 alters the sensor values at 200 times per second which is faster than the DME actually reads&processes those sensors. Depending on the JB4 map used the boost target to gas pedal input is remapped which on some maps feels more aggressive and others less aggressive depending on the settings. With EWG vehicles like the M3/M4 though it's 100% seamless and as smooth as stock.

On older pneumatic wastegate vehicles there is a separate PID system for running the pneumatic boost solenoids and if those are not set just right the tuning won't be as smooth during low throttle. That has nothing to do with this platform though.

Mike

[mike@x-ph.com]

Originally Posted by JoeyBananas

Might be a dumb question but I keep reading threads or posts when people discuss a flash vs piggyback etc and I have read a few people say the Flash tunes are "smoother".

I'm going to hook up the fuel mass connector but even so, will there be hesitation, stuttering etc that can be expected as the norm?

Thanks

As explained by Mike, this is the case with pneumatic wastegates only. Car is not as smooth during normal operation

With the M3 / M4, the JB4 is just as smooth as stock

[JoeyBananas]

Awesome, thanks guys!

[s0ul]

JB4 is smooth as my shiny buns.

[sittingmongoose]

At first start up the car can be a little jumpy. However I did notice this before the jb4, it just seems more often now. It goes away after driving for like 15-30 seconds though.

[pikkagtr]

Hell yeah it's not smooth
Map2+e85 and its a violent experience through 3 gears

[FC4]

Originally Posted by JoeyBananas

Might be a dumb question but I keep reading threads or posts when people discuss a flash vs piggyback etc and I have read a few people say the Flash tunes are "smoother".

It's just a load of bullshit. Whenever someone says the pull is "as smooth as stock" or "smoother than JB4", all that means is the difference is marginal. When you add only 20 HP to a car, of course it's going to feel "as smooth" as stock. Add 100 HP and suddenly the kick once the turbos come on full boil is exacerbated.

To imply that one is smooth and another is bucking and hesitating as it climbs through the powerband is laughable. But, hey...I remember my first turbo car, too.

[JoeyBananas]

Originally Posted by FC4

It's just a load of bullshit. Whenever someone says the pull is "as smooth as stock" or "smoother than JB4", all that means is the difference is marginal. When you add only 20 HP to a car, of course it's going to feel "as smooth" as stock. Add 100 HP and suddenly the kick once the turbos come on full boil is exacerbated.

To imply that one is smooth and another is bucking and hesitating as it climbs through the powerband is laughable. But, hey...I remember my first turbo car, too.

Haha ok good, thanks. Yeah I'm just concerned with hesitation and stuttering

[Reach]

There's a bit of a middle ground as well. It's not the JB4's fault per se, but when you're pushing the envelope of what the stock system is designed to deliver, you can run into bumpy delivery. Look at the green line below, that's 5th gear on map 5. With pump 93 fuel, I think this is running right at the edge of fueling capacity. Keep in mind this is with smoothing on in the graph, if I turn smoothing off the peaks and valleys are even worse.




Compare to stock (lower lines)


As to whether JB4 is smoother than a tune, well, that depends 100% on what the tune is and I haven't seen anything that's made me put the Jb4 on the shelf. (yet)

[MyFragileHalogen]

Definitely there is delay until the full boost comes. It is never the same as stock; don't trust it if someone says it performs smooth and lagless just like stock. It's more of whether it would be acceptable within the person's expectation.