J Pipe Delete Issues JZX110

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DangerousJZX
Posts: 33
Joined: Sun Jan 06, 2019 8:23 pm

J Pipe Delete Issues JZX110

Post by DangerousJZX » Tue Jan 08, 2019 12:34 am

Righty so here goes a little bit of info for those who want ot run a J Pipe delete on a stock ECU. This is on a factory manual X110 not an auto. For reference Autos's accommodate the J Pipe delete a lit better as you don't have a clutching break in the RPMs when shifting up or down and low speeds.

Here is the issue.

When installing a J Pipe delete you obviously take away the J pipe. The purpose of the J pipe is to provide stability for all of the air going into the turbo and where it occurs, air coming back out of the turbo. So as we all know the air goes into the intake, through the MAF and into j pipe which feeds the turbine compressor.

The way the J pipe is designed means that there is always some air in the piping system. When the car is running and accelerating the air is fed in by natural air flow as well as assisted by the hair dryer sucking the air in. Make sense? So that's not a problem for the j pipe delete as that requires air just getting sucked into the turbine.

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Now the next part, slowing down, coming to a hard stop or changing gears slowly at low RPM. If anyone understands airflow and turbulent air this will make some sense. What happens with the stock J pipe is the section of the j pipe (at the photo its above where the black silicone feeds into the j pipe) acts like an accumulator. It gathers any air coming out of the turbine compressor and creates a more stable air to go back through the MAF. That air being nice an stable helps the MAF go "oh ok the air is stable so I will keep a constant fuel rate going".

With a J pipe delete that does not exist. The air just whooshes in an uncontrolled tumble and that tells the MAF to remove more fuel but then the intake empties of air which then causes the car to stall from bulk over fueling as the RPM does not match the fuel. So it basically causes a nice little shutdown which is super fun at low speed in traffic meaning them brakes get heavy.

So if that makes some sense to you, here is another factor that causes it to get worse.

No BOV. This means there is no air being recirculated into the intake piping which helps to stabilize the MAF readings and keep air in the intake for that little bit longer..

So that should make sense to most. Basically J pipe empties of air when clutching in or coming to a hard stop causing the car to stall.

So the solutions

MAP conversion with new ECU and the problem is a non issue.
Recalculation BOV - yes I know you all want them flutters but a J pipe will give you enough of that as it is.

Lastly this little thing - it's called an air flow straightener. Now this is just aluminium honeycomb. This straightens and stabilizes that tumbling air flow and allows the MAF to take readings on stable air instead of turbulent air which causes the MAF to go spastic. Fit these pre and post MAF to create nice smooth air.

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I have run all sorts of combinations and had my old Snap on technicians doing readings while driving and idling to come up with this solution working best. Ideally get an aftermarket ECU but if you can't afford one or don't feel the need for one then this will work. Hard stops will still make the car stall, but at low speeds and slow gear changing that will be greatly reduced. Note that if you fit a J pipe, you and your ECU will have to go through the learning process.

Additionally this worked 100% on my car, it may not work for all applications depending on other modification to things like turbos, intakes, cams etc but I do know for a fact it worked,
I like cars

KuniGarage
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Posts: 176
Joined: Sun Dec 23, 2018 1:57 am

Re: J Pipe Delete Issues JZX110

Post by KuniGarage » Tue Jan 08, 2019 8:39 am

😍😍😍🥰

Keep up the awesome posts!

DangerousJZX
Posts: 33
Joined: Sun Jan 06, 2019 8:23 pm

Re: J Pipe Delete Issues JZX110

Post by DangerousJZX » Tue Jan 08, 2019 9:17 am

I think that's all my useful information used up for today.
I like cars

Cambo
Posts: 10
Joined: Fri Jan 11, 2019 8:23 am

Re: J Pipe Delete Issues JZX110

Post by Cambo » Fri Jan 11, 2019 10:34 am

Dave smashing out the knowledge as always! Top work.

DangerousJZX
Posts: 33
Joined: Sun Jan 06, 2019 8:23 pm

Re: J Pipe Delete Issues JZX110

Post by DangerousJZX » Fri Jan 11, 2019 11:00 am

It's what I do best. Useless information haha
I like cars

Chemiis
Posts: 1
Joined: Sun Oct 27, 2019 8:42 pm

Re: J Pipe Delete Issues JZX110

Post by Chemiis » Sun Oct 27, 2019 8:44 pm

Anyone know where you can buy the aluminium honeycomb from?

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