MaverickC43

I had the jb4 on for 2 weeks
Feels faster but don’t have great times yet.
took it off to bring it into the dealer and the car feels better/tighter back stock.
anyone else experience this?
the car feels looser / erratic with the jb4, maybe that’s why my 0-60 aren’t improving?

VTSummit

Mine always felt better with the JB4 on it- are you sure you downloaded the correct package into it? Even Map 1 was easy to notice, but Map 3 was really perked up.

GermanCarShow

What are your times with and without? Inquiring minds want to know.

MaverickC43

Best 1/4 mile without 12.13@114
best with 12.10@116

MaverickC43

0-60
without 3.95
with 3.97

MaverickC43

Now my best gain was in the 60-130
without 12.27
with 11.10

which is why things are confusing me

i was hoping to be 3.6-3.7 0-60
and 11.5 1/4

i think others are doing these times.

I’ll keep working and logging

TwoC400s

My C400 similarly did not see much improvement at the drag strip with the JB4.

The biggest thing that stands out to me is that the JB4 seems to actually hurt low end performance. My stock 60ft times were a bit better than with the JB4, but my trap speed was higher by a couple MPH.

GermanCarShow

Which map? Which fuel?

TwoC400s

Map 2, 93 octane.

MaverickC43

Map 2
93 + 4 gal e85

Griley

For me Map 1 seemed faster than Map 2, there is definitely a difference with JB4 being off feels less power, but not a huge difference but you can definitely notice when it’s turned off, But for some strange reason Map 1 seem snappier than Map 2.

TwoC400s

I think with the E85 you should be good to use map 3.

Do have the green wire connected?

MaverickC43

Yep.

GermanCarShow

Is it common see very small differences in measured performance with maps 1 or 2 on 93 octane?

TwoC400s

Honestly, I have no idea. In my case, all my JB4 passes have been slower than my fastest stock pass when comparing elapsed time, despite the fact that my trap speeds increased by a couple of mph.

MaverickC43

Some people have good luck with it from what I’ve read but others not. Its confusing to me

Howyalivin

Something is up with your quarter mile time. That's not a stock time by any means. It's actually quicker than a stock C63. Your car was likely tuned before you bought it. That's the first thing to figure out.

MaverickC43

The dealer would not have seen that?
it was CPO, and has been in the dealer many times I’m sure it had some coding done when I got my center Speedo screen replaced.

MaverickC43

Maybe I’m good at going fast
lol

GermanCarShow

Going a hair under 4.0 in 0-60 is also not stock. From what I understand, most magazines had it between 4.4 and 4.8? Others who are more well read can comment on that, but I'm certain that under 4.0 is not stock.

How would one find out what tune has been applied to their car? Is there a digital signature that a Xentry system could read that would identify the company?

C43HeartBoost

Some data logging on map 0 may help.

MaverickC43

Seems strange that would not have been noticed.
and even more concerning is that the fai didn’t improve performance. Most people said you’d see gains with an intake & tune

GermanCarShow

What's a fai?

Do you have an aftermarket intake? What other mods do you have?

MaverickC43

Front air intake (logos engineering)

GermanCarShow

Oh, as opposed to the factory rear air intake?