Change of Times...Exhaust Expectations..?

[PRL Motorsports]

So what you're saying is you just went open downpipe or am I reading "dropping the exhaust" wrong?

Yes, we dropped or un-bolted the exhaust after our downpipe and front pipe.

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[zerogravity]

We simply dropped the exhaust between dyno runs to see if the factory cat-back exhaust was a restriction and found 0 power gains (maybe 1-2 ft/lbs tq which is hardly recordable). There is no need to "tune" for the dropping of the exhaust or increased exhaust piping diameter, as this does not change AFRs are engine/turbo characteristics. If it did we would see power gains (positive or negative) and parameter changes. There were none.

Thanks for chiming in PRL. I wish i could test this myself. Not that i doubt your findings but to test for my own education. With larger diameter piping/free-er flowing exhaust, i would think the tiny turbo would still breath better than stock, but maybe the ecu kicked in an corrected and temp/afr changes? Maybe the smaller piping kept the exhausts speed up so spooling never changed? Im wondering the reason may just be the small turbo? I would love to know why this is so.

 

[Myx]

Thanks for chiming in PRL. I wish i could test this myself. Not that i doubt your findings but to test for my own education. With larger diameter piping/free-er flowing exhaust, i would think the tiny turbo would still breath better than stock, but maybe the ecu kicked in an corrected and temp/afr changes? Maybe the smaller piping kept the exhausts speed up so spooling never changed? Im wondering the reason may just be the small turbo? I would love to know why this is so.

You are not alone in thinking this way. I'm always asking why. I am thankful that PRL dropped the exhaust and reported their findings. I mean, they could've said they gained X amount of hp/tq, had the dyno showing this (Since there are many ways of doing this) and then went on and sold a product until people found out otherwise.

My days of dynoing are over. So I'm going to put my energy on other items that I know will work. Already have the down/front pipe on order. Still baffles me though and will keep looking to see the 'why' this is the case with this application (no hp/tq gained after the downpipe).

 

[360glitch]

Thanks for chiming in PRL. I wish i could test this myself. Not that i doubt your findings but to test for my own education. With larger diameter piping/free-er flowing exhaust, i would think the tiny turbo would still breath better than stock, but maybe the ecu kicked in an corrected and temp/afr changes? Maybe the smaller piping kept the exhausts speed up so spooling never changed? Im wondering the reason may just be the small turbo? I would love to know why this is so.

Have you seen the exhaust turbine on the turbo? It’s super tiny. Borderline embarrassingly tiny. That is where the exhaust is choked.

 

[zerogravity]

You are not alone in thinking this way. I'm always asking why. I am thankful that PRL dropped the exhaust and reported their findings. I mean, they could've said they gained X amount of hp/tq, had the dyno showing this (Since there are many ways of doing this) and then went on and sold a product until people found out otherwise.

My days of dynoing are over. So I'm going to put my energy on other items that I know will work. Already have the down/front pipe on order. Still baffles me though and will keep looking to see the 'why' this is the case with this application (no hp/tq gained after the downpipe).

See me too..spending 1000's on the dyno to see 2-3whp gains to 25+whp gains in several hours are behind me as well. Guess we will have to wait when someone actually does.

Have you seen the exhaust turbine on the turbo? It’s super tiny. Borderline embarrassingly tiny. That is where the exhaust is choked.

I suspected this and posted on another thread about the turbo being so small. Then spoke to my buddy and he said the turbo was so small, it was actually kinda embarrassing..lol. so I guess I'll have to install a bigger turbo to support the rest of the mods.

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