So what is the deal with exhaust?
#1
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So what is the deal with exhaust?
I am thinking about buying exhaust for my A4 1.8T, specifically neuspeed/borla catback.
My question is does it increase horsepower/torque? People on the S4 board are claiming no. That the eurpeanspeed.com chip shootout proves no. Anybody do a dyno before/after? G-tech pro? In-grear acceleration times, etc.
I heard exhaust on a NA engine is questionable, some backpressure is supposed to help torque for a NA engine. But for turbos, I thought the more flow the better?
TIA
Jeff
My question is does it increase horsepower/torque? People on the S4 board are claiming no. That the eurpeanspeed.com chip shootout proves no. Anybody do a dyno before/after? G-tech pro? In-grear acceleration times, etc.
I heard exhaust on a NA engine is questionable, some backpressure is supposed to help torque for a NA engine. But for turbos, I thought the more flow the better?
TIA
Jeff
#2
independent tests show they rarely help
Many others still swear by them. If they do help for you, the improvement will be small, perhaps 15HP. It will also help almost only at the top end.
Frankly, most people are satisfied with their exhaust upgrades, even when the improvement is only psychological. So if you can afford it, you may want to consider it.
Frankly, most people are satisfied with their exhaust upgrades, even when the improvement is only psychological. So if you can afford it, you may want to consider it.
#3
Re: Exhaust improvements
The main benefit of a larger exhaust is improved gas flow at reduced pressure drop. It does not necessarily equate to higher HP numbers. Pumping losses are reduced as well because the engine does not have to expend as much energy to get the gasses out the back end of the vehicle.
When the engine breaths more freely through a freed up exhaust, throttle response should be crisper. A less constrictive air intake also helps. The change is more noticeable on a normally aspirated car than on a turbo car.
When the engine breaths more freely through a freed up exhaust, throttle response should be crisper. A less constrictive air intake also helps. The change is more noticeable on a normally aspirated car than on a turbo car.
#4
at that the same time on a forced induction car there is less stress...
on the turbo due to smaller back pressure due to the better flowing exhaust. Also, most exhausts systems are lighter than the stock units which is always nice to make our hogs of cars a little lighter
#5
True....don't forget they do help decrease spool up time.
I just installed a Scorpion cat back on my S4. It does feel like its a little stronger up top. It's barely louder than stock, which is what I wanted.
#6
Dyno of 1.8T w/stock exh. and w/Supersprint cat back, indicated...
...a slight loss (~3-5HP) on the low end (below ~2,500rpm or thereabouts) in exchange for a nice bump (~10HP) above 4,500rpm.
These are the results I'd expect on a NA engine (i.e. the 1.8T below 2000rpm) if installing a larger exhaust system. As mentioned below, turbo will spool quicker due to less back pressure vs stock exhaust.
The dyno plot is somewhere in this forum, I saw it within the past ~6 weeks.
Do a search.
These are the results I'd expect on a NA engine (i.e. the 1.8T below 2000rpm) if installing a larger exhaust system. As mentioned below, turbo will spool quicker due to less back pressure vs stock exhaust.
The dyno plot is somewhere in this forum, I saw it within the past ~6 weeks.
Do a search.
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