MBRP hemi torque loss

2015sxthemieric · Jul 30, 2016

2015 hemi sxt quad cab long box k n intake. 2.5 lift 1.5 rear

hi,

I put mbrp cat back 409 18in flow through baffled exghaust on 6 months ago. I noticed a loss in low end torque. I tow my boat around 15oo lbs and notice it bogging down. for 40o hp I feel like this isn't right. higher rpm 550o I notice increase HP.

I've always heard with the hemi this is the best exghaust even my dealer recommended it.

sound is great my fuel is worse at 16.5L per 100km

has anyone experienced the same issues? should I go back to stock? or what other mufflers are recommended with proper back pressure.

I went to mbrp because it's canadian. after expressing my issues I was never Givin a reply.

2015sxthemieric · Jul 30, 2016

not looking to save fuel but towing 1500 when my max tow is 10k should not be an issue.

before exghaust 14-16L per 100km

more torque off line.

lower high end rpm HP though.

p.s for hemi the cold air makes 0 difference save your money

HemiPower36 · Jul 31, 2016

I have the same exact complaint from my magnaflow 14".

I was thinking of trying the Carven RX-A set up. Should probably hit up Hemifever tuning. Been to long. Should have done it awhile ago. Sorry you are having the same experience.

HemiPower36 · Jul 31, 2016

^ my ******** dyno doesn't lie.

Magna 14" is a no go at this station.

misuracaf10 · Jul 31, 2016

I haven't noticed any loss in power with a 14 in borla with resonator still on. Vehicle is tuned as well though

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2015sxthemieric · Jul 31, 2016

Kyle- no I haven't dyno tested before or after.

I just feel it, only notice it really when towing my boat. but there's a huge difference from before the cat back swap.

hemi power - have you tried this, I'm guessing they would flash the system then retune the settings? or is this a chip tuner.

still a 2015 not looking to void the warranty just yet. but I want a solution

currently I only have cold air and the exghaust.

2015sxthemieric · Jul 31, 2016

I found it strange that the exghaust was the flow through baffled type. it's basically straight piped.

read a few studies some say hemi work better with the increase flow. others strongly recommend something that maintains proper back pressure.

changing the exghaust did make a low.end torque difference due to the loss of back pressure. I wonder if a tune would even help that.

anyone know if a tune voids warrenty

HemiPower36 · Jul 31, 2016

2015sxthemieric said:
hemi power - have you tried this, I'm guessing they would flash the system then retune the settings? or is this a chip tuner.
.

I have not tried anything yet. Still have the stock tune with the magnaflow 14". However, there is a forum member on here that does custom tunes. I am sure he will chime in soon *cough* hemi450hp *cough*

He told me it would help out. I haven't committed yet. More of a $$$ issue right now than anything. He is a vendor on here.

Kytow · Jul 31, 2016

I'm running cats, and resonators. That's it. My butt dyno didn't notice.

Sent from somewhere with confusion.

Riccochet · Aug 2, 2016

When I put a 18" mangaflow on I noticed a slight loss of low end torque as well. Most likely the torque management playing fucky on us.

Really need to tune. Contact Moe's, get a tuner, get Hemifever tuning and tell them what you'll be using the truck for. He'll make you a tow tune.

doz · Aug 2, 2016

Go look under your truck. The restriction in your exhaust is your manifold and y-pipe. It is HARDLY the muffler. Exhaust gets restricted way before that. You didnt lose anything, you just hear when the engine is digging and it makes it sound like its bogged down a bit.

Hemi450hp · Aug 2, 2016

I have to agree with doz. I have seen a few people over the years claim to have felt a loss of power with a free flowing muffler, but every test I have done has shown that a more open exhaust will always make more power on these trucks. The increased sound makes it seem like the truck is working harder or like you maybe arent going as fast as you were before with less noise.

Having said that, a tuner always need to be the first mod anyone does to their truck if you are looking for performance. Nothing else you do to the truck will show better gains than a tuner will, and you will benefit more from each of those airflow mods once you can properly tune for them as well.

mhb1638 · Aug 7, 2016

I recall many many years ago reading an article in a mopar magazine that the Mopar performance team used Flowmaster mufflers (even had a picture of the set up while on the dyno) when dynoing their crate engines. Again this was long ago but I recall some forums were all in shock how Mopar used chambered mufflers for their tests.
As for low end loss I can't really say. Just stating what I recall long ago.

xrsman · Aug 7, 2016

The Only way your mileage should be any different is if you're heavier on the petal. My MBRP didn't hurt my mileage at all, I didn't notice a power loss either

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Sillygoose · Aug 7, 2016

Go back to stock or get a chambered Flowmaster. When you open the exhaust up a little, low end will always suffer, top end gets better, just how it is

MBRP hemi torque loss

2015sxthemieric

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HemiPower36

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misuracaf10

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2015sxthemieric

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Kytow

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