Hi guys,

Today i've fitted a Janspeed 4-1 manifold to my JCW 210.
I've used a new stock cat welded to the manifold and i'm using the stock JCW catback.
Only other performance mods are ITG drop-in cone filter, deflap, GP cooler and remap (done after the mods).

I was wondering if i needed another remap after fitting this manifold.
Sound is really awesome, but i've definitely lost some low down grunt and there's a slight hiccup at 3k rpm.
Don't know if this is character or something that can be won back with software.
The top-end is definitely better!

I honestly think it's the exhaust gas scavenging that's completely messed up right now, so maybe a smaller pulley to increase mixture volume is my thought?

What do you guys think?

Otto

 

The ECU may adapt fine after a few start and runs, but if it's been custom tuned it may not adapt as well as from a factory tune. Do you have a dyno near you?, after opening up the exhaust like that and working off a custom tune, I'd put it on a dyno with an AFR sniffer to make sure you're not running too lean at the top end, don't worry about power or adjustments, JUST DOUBLE CHECK THE AFR you can work on a re-tune and other needed parts after you are sure about the AFR.
And Don't Run It At WOT Too Often Until You're Sure.

 

Yes will check that with the tuner, thanks!

The car does pop and burble everywhere when i let off the gas.
High or low revs, pops and burbles, this usually indicates a rich mixture, right?

 

Just to clarify...
You got a 4-1 header exhaust right? Guess manifold is technically right, but a header is used to show its a free flowing unit, as opposed to the old school cast iron manifolds of years back.

 

Okay, it's a weird thing.
I changed my plugs and leads for new ones, but no luck, still a hiccup between 2-3k rpm..
My boost gauge reads a consistent 0.7 bar to 0.9 at redline, no yoyo..

Someone has an idea?
I swapped back to stock JCW map, but didn't work as planned, still the hiccup..

 

No boost usually equals a bad bypass valve...
It might be stuck partly open/shut, or the vacuumline not connected...maybe acting slow?
About 1 bar if I am doing the math right is ok...most use psi here in the states...15-19 psi is about right...
Think the hiccup is just the bypass valve closing, and the motor switching from unboisted to boosted operation...between 2000-3000 rpms is when it closes...
Usually it is pretty slight...but some aftermarket ones, like DT with the stinger spring can make it noticeable.

 

To clarify some things, these 'hiccups' only happen under these circumstances:

- 2.5 - 3.5k rpm, lower or higher is very smooth.
- Half to full throttle, closed to half throttle feels good, but any further (to full) gives a stutter and a flat spot.

I'm also thinking BPV, but a leaking one would give me less boost on the gauge, right?
I didn't have any of this with the old (stock manifold)...

 

My other guess....
Things are running a bit leaner with the new parts....
So you have a bit more knock or going activity....
So the ecu is usually seeing it when the bypass valve closes....the intake temps go up...so the ecu is retarding the timing of making other changes....result is what you see...
Before, everything was optimized for your parts....
Now not so much.

 

I removed the remap, so stock jcw software is on it, remap or not, stuttering was exactly the same...
I know stock mapping is running rich and my remap was running even richer, so it should've made a difference, right?

I'm checking my vacuum lines tonight and i'm also zip tie'ing my BPV to see if it makes a difference..

 

Guys, problem is fixed!!
The line from the FPR to the intake was torn and thus leaking boost.
New line fitted and car is running flawless!

Thanks for thinking with me!

Otto

 

Glad you found it, esp with what it ended up being, too much loss of vacuum there can cause a bad "lean out" condition.

 

Could you post up any help or info regarding welding the stock cat to the janspeed header?
This is exactly what I want to do, but have no clue at the moment!
Thanks

 

I will help you as far as i can.
I bought the manifold from a friend and he had the cat welded to it:



As you can see, he used a new flexpipe and cat, but i didn't do any of the physical work myself so can't tell you first-hand experienced...

Otto