[Managable]

So my car’s year is 2014 and I have stage 1 bootmod3, catless downpipe, unplugged maf (misfires a lot and undrivable with in plugged in), and cold air intake. I don’t have access to a dyno but I do have the sport display. When I have my exhaust connected it peaks at 380hp on the sport display but when I run an open downpipe is peaks at 450hp. I’ve been looking up a bunch of information to see whether this will over boost my turbo and cause damages to it etc. I love the sound and power it adds but I wanna know what’s adding that power and how it will affect the longevity compared to a connected exhaust. I’ve done pulls tracking the pre throttle psi and open dp peaks at 18psi full throttle and connected exhausts peaks at 17.5psi (it was only one pull). Yes I know it burns the bottom of the car I’m looking at turning it into an open dump if it’s okay to run.

[Slumped335]

What intake are you running that would make your MAF useless? Could it be a bad MAF?

While I'm sure the less restrictive exhaust would technically make more power, I doubt its a 70hp difference. At that point you might as well just get a straight pipe kit and call it a day. Better than whatever may happen with a open dump under the car.

As for the boost.... Back pressure is good for low end torque (could be wrong but I've heard that's the general consensus), But is the 0.5 psi of boost worth having a open dump? I feel like the means are not worth the gains.

What is your goal in this? More Power? Sound?

[n55david]

Originally Posted by Managable

So my car’s year is 2014 and I have stage 1 bootmod3, catless downpipe, unplugged maf (misfires a lot and undrivable with in plugged in), and cold air intake. I don’t have access to a dyno but I do have the sport display. When I have my exhaust connected it peaks at 380hp on the sport display but when I run an open downpipe is peaks at 450hp. I’ve been looking up a bunch of information to see whether this will over boost my turbo and cause damages to it etc. I love the sound and power it adds but I wanna know what’s adding that power and how it will affect the longevity compared to a connected exhaust. I’ve done pulls tracking the pre throttle psi and open dp peaks at 18psi full throttle and connected exhausts peaks at 17.5psi (it was only one pull). Yes I know it burns the bottom of the car I’m looking at turning it into an open dump if it’s okay to run.

If you can't drive the car with the maf plugged in you have a ton of issues that need to be addressed asap.

Youre not gaining big power with an open downpipe unfortunately.. btw the guages aren't exactly accurate

Originally Posted by Slumped335

What intake are you running that would make your MAF useless? Could it be a bad MAF?

While I'm sure the less restrictive exhaust would technically make more power, I doubt its a 70hp difference. At that point you might as well just get a straight pipe kit and call it a day. Better than whatever may happen with a open dump under the car.

As for the boost.... Back pressure is good for low end torque (could be wrong but I've heard that's the general consensus), But is the 0.5 psi of boost worth having a open dump? I feel like the means are not worth the gains.

What is your goal in this? More Power? Sound?

Backpressure is bad for engines actually.. however because of how physics work.. exhaust pipe (diameter and length of it etc) creates high and low pressures and a bunch of other stuff that increase the speed of exhaust leaving from the engine and so on.. it's why it's important to have the right exhaust. On turbo engines for high hp having almost no exhaust is better. The size of the engine, turbo and rpm will dictate but generally an open exhaust of no more than a few feet is best.

[LA1Z24]

All I have to say is this...

You don't magically just get 70hp because you disconnected the exhaust.

Also, fix your car. You're worried about engine damage but you're knowingly driving it around in a broken state. So yea....fix your shit.

[n55david]

Originally Posted by LA1Z24

All I have to say is this...

You don't magically just get 70hp because you disconnected the exhaust.

Also, fix your car. You're worried about engine damage but you're knowingly driving it around in a broken state. So yea....fix your shit.

This.. it's hilarious but this

[Managable]

Originally Posted by LA1Z24

All I have to say is this...

You don't magically just get 70hp because you disconnected the exhaust.

Also, fix your car. You're worried about engine damage but you're knowingly driving it around in a broken state. So yea....fix your shit.

So after I installed my catless downpipe I started getting the misfires. I read a lot of forums and couldn’t find a solution. Unplugging the Maf and putting it in alpha-n mode seemed to be my best bet any ideas on how to fix it cause I wouldn’t mind it working. Also I did buy a new MAF and plug it in for it to yield the exact same misfiring issues.

[Managable]

Originally Posted by n55david

If you can't drive the car with the maf plugged in you have a ton of issues that need to be addressed asap.

Youre not gaining big power with an open downpipe unfortunately.. btw the guages aren't exactly accurate



Backpressure is bad for engines actually.. however because of how physics work.. exhaust pipe (diameter and length of it etc) creates high and low pressures and a bunch of other stuff that increase the speed of exhaust leaving from the engine and so on.. it's why it's important to have the right exhaust. On turbo engines for high hp having almost no exhaust is better. The size of the engine, turbo and rpm will dictate but generally an open exhaust of no more than a few feet is best.

I know 70hp wasn’t probably right, but still a jump in power just worried me that I could blow my turbo. Like I replied to the other guy my misfires happened as soon as I added my downpipe. I did have an exhaust leaked which I later fixed and tried it plugged it (same issue).

[thejeremyman9]

If your car ran fine before you installed the DP then you should start there... Mostly likely problem is with the O2 sensors. Did you swap the plugs? Did you damage the O2s when moving them? Where's your datalogs?

[delaineyklein]

Originally Posted by Managable

So after I installed my catless downpipe I started getting the misfires. I read a lot of forums and couldn’t find a solution. Unplugging the Maf and putting it in alpha-n mode seemed to be my best bet any ideas on how to fix it cause I wouldn’t mind it working. Also I did buy a new MAF and plug it in for it to yield the exact same misfiring issues.

get it smoked, you have a vacuum leak. i had a rather large one coming from my camshaft seal and valve cover last year. i bought a new MAF and it still misfired and idled choppy. started it up with it unplugged and it idled fine. unplugging it is just hiding the real issue. the only reason it’s “running better” is because your computer isn’t getting data from the MAF, instead it’s running off calculated estimates.

you already have an increased air outake from your downpipe. your car’s pulling way too much air in from places it shouldn’t and pushing too much air out. the ECU doesn’t see an issue because the data’s in “equilibrium”. the tune isn’t helping either, as your computer’s coded to accept higher a higher fuel/air ratio. your car’s dumping fuel to overcompensate. plug it back in and P0171/ P0174/ 11CF30 codes will pop up in your DME, they’re indicators of vacuum leaks.

you need to flash back to stock and take it to get smoked and see what damage you’ve done to your internals, if any. ironically, you lose power and drivability when you unplug your MAF. prioritize your maintenance over power.

[thejeremyman9]

Originally Posted by delaineyklein

the tune isn’t helping either, as your computer’s coded to accept higher a higher fuel/air ratio. your car’s dumping fuel to overcompensate.

? tune doesnt increase AFR

[delaineyklein]

yeah you’re right, the ratio would stay the same. i meant the amounts.

[AmuroRay]

Sounds like you damaged the O2 sensor or harness