Exhaust Comparison Chart
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From: Maryland
It has Magnaflow resonators right before the rear sway. The X pipe and rear resonators are custom jobs by the people who installed it (Lorentz Automotive in Lewisville, TX - highly recommended). They have high flow cats that are quite small that are going in pretty soon (next week?) in place of the stock ones in there now. Later, when I build the top end of the motor, headers will also go in. Not sure which ones yet though. There is a local member of this forum that took vid clips of us at the track several weeks ago. I don't know where he went!! I want some clips of my exhaust!
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From: Lake Worth, FL
Originally posted by Hraesvelg
Where the hell did you get those numbers!?!?
Where the hell did you get those numbers!?!?
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From: Lake Worth, FL
Alright, I made my decision, getting Stillen installed in the morning. One concern that I had was how the Stillen looked (like a cut off pipe). But now Stillen has new tips and you really can't beat the fit except for maybe the Nismo.
http://www.stillen.com/Sportscars_de...d=35098&page=1
http://www.stillen.com/Sportscars_de...d=35098&page=1
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From: Lake Worth, FL
Got them! Only drove 20 miles back to the office. First impressions, quieter than expected. Kind of disappointed at first, but then happier on acceleration. Quite on the highway, just a couple of octaves louder than stock. Back on the surface streets noticed you can now feel the engine run. Kind of like having a subwoofer, not to noticeable at low volume (idle) but on high volume (acceleration) you get a real since of being there. To early to tell, but maybe Stillen got it right, maybe I don't want it as loud as I thought.
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From: Jamaica - Building H
Free Flow is BAD for these motors!
Originally posted by ares
I am skeptical of borla; the whole 2 pipes into one muffler is a bit questionable to me; not that it matter; it has the H pipe anyway. I think I know the purpose of the Hpipe; the viper has it because it has side exhaust and you only heard 5 cylinders from each side leading to a farm tractor sound; so they put in the crossover to let the pulses mingle.
but we have rear exhaust; so whats the point? also as a result there are if anything; more bends in the pipes keeping the sharp bends to go sideways into the muffler.
stillen is similiar but without the hpipe; and it has 2 parralel mufflers.
injen would just seem to be without question the most free flowing exhaust system with the least bends. of course free flowing isnt always better; but its odd that of the 3 listed they order them borla>injen>stillen... borla would seem the most close to stock with the bends yet gets the most increase... while injen being the least restrictive and farthest from stock gets the second most...
doesnt make very much logical sense.
psst... vendors; do a proper shootout with some results that are impartial and confirmed. I havent seen such a thing yet; this whole 23hp gain thing is nuts and unbeleivable.
I am skeptical of borla; the whole 2 pipes into one muffler is a bit questionable to me; not that it matter; it has the H pipe anyway. I think I know the purpose of the Hpipe; the viper has it because it has side exhaust and you only heard 5 cylinders from each side leading to a farm tractor sound; so they put in the crossover to let the pulses mingle.
but we have rear exhaust; so whats the point? also as a result there are if anything; more bends in the pipes keeping the sharp bends to go sideways into the muffler.
stillen is similiar but without the hpipe; and it has 2 parralel mufflers.
injen would just seem to be without question the most free flowing exhaust system with the least bends. of course free flowing isnt always better; but its odd that of the 3 listed they order them borla>injen>stillen... borla would seem the most close to stock with the bends yet gets the most increase... while injen being the least restrictive and farthest from stock gets the second most...
doesnt make very much logical sense.
psst... vendors; do a proper shootout with some results that are impartial and confirmed. I havent seen such a thing yet; this whole 23hp gain thing is nuts and unbeleivable.
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Re: Free Flow is BAD for these motors!
Originally posted by BLOBYU
The 3.5L motor needs backpressure. That's why the STILLEN unit makes more power. You'll not be happy if you are looking for power.
The 3.5L motor needs backpressure. That's why the STILLEN unit makes more power. You'll not be happy if you are looking for power.
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From: Jamaica - Building H
agreed....very generalized. Left out a few important things.
However, your power gain when combining a Borla or STILLEN with any type of F/I will net higher than one with a straight through design. The size of the piping already makes it freer flowing. Add to that the scavenging of the x or h pipes...
But relative to the engine's needs - the backpressure needs to be there to see the best gains. Especially when discussing torque numbers. There is a happy medium - but it does need backpressure. Talk to Mike Kojima at Nissan (engineer).
However, your power gain when combining a Borla or STILLEN with any type of F/I will net higher than one with a straight through design. The size of the piping already makes it freer flowing. Add to that the scavenging of the x or h pipes...
But relative to the engine's needs - the backpressure needs to be there to see the best gains. Especially when discussing torque numbers. There is a happy medium - but it does need backpressure. Talk to Mike Kojima at Nissan (engineer).
Last edited by BLOBYU; Jan 8, 2004 at 04:09 PM.
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From: Cerritos, CA
There seems to be some confusion as to what crossover pipes do. Here's a little info from FordMuscle.com comparing the two styles.
Here's another magazine comparison (link to PDF) that tests the two in the real world. The only compromise with choosing to go with crossover pipes is increased weight but for the increase in both HP and TQ, it's of no consequence. For the record I went Borla but am seriously considering the Stillen for the next car (G35c).
X Versus H
It's long been known that connecting the two sides of a dual exhaust system, shortly after the headers, increases power and reduces sound. However in a traditional "H" pipe, only sound and pressure waves cross through the connection. Gasses take the route of lowest pressure, which is straight out the pipe, rather than making a 90 degree turn in to the H. Indy and Nascar teams have been using "X" type crossovers for quite some time. In an "X" pipe the gasses from both cylinder banks actually pass through a common area. This not only provides the benefits of some sound wave cancellation, but also increases the scavenging effect, helping draw out spent charge from the combustion chamber. So how much of an increase does an X gain over an H? It's hard to say, especially considering that every combination will yield varying gains. In theory an X will work better as rpms go up.
It's long been known that connecting the two sides of a dual exhaust system, shortly after the headers, increases power and reduces sound. However in a traditional "H" pipe, only sound and pressure waves cross through the connection. Gasses take the route of lowest pressure, which is straight out the pipe, rather than making a 90 degree turn in to the H. Indy and Nascar teams have been using "X" type crossovers for quite some time. In an "X" pipe the gasses from both cylinder banks actually pass through a common area. This not only provides the benefits of some sound wave cancellation, but also increases the scavenging effect, helping draw out spent charge from the combustion chamber. So how much of an increase does an X gain over an H? It's hard to say, especially considering that every combination will yield varying gains. In theory an X will work better as rpms go up.
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From: Maryland
I would say that you will hit a 13.7 with a dual exhaust if you ran a 14.0 without one. That is pretty nice gains to be had in the exhaust for the people that think there are none. I picked up .4 in the quarter with a dual exhaust, flywheel (bad for drag racing), and some lighter wheels (maybe worth .05-.10). An exhaust on the Z can make great power.
Mike Kojima is an engineer focused on making the stock Z run (hopefully he was involved in the Z to be a reliable source). I would trust the aftermarket more than an engineer for factory cars. He engineers a vehicle to perform at a level that is good enough (to also meet emmsion requirements, etc) and does not concentrate on maximizing anything except (hopefully) a customer's percieved value.
Mike Kojima is an engineer focused on making the stock Z run (hopefully he was involved in the Z to be a reliable source). I would trust the aftermarket more than an engineer for factory cars. He engineers a vehicle to perform at a level that is good enough (to also meet emmsion requirements, etc) and does not concentrate on maximizing anything except (hopefully) a customer's percieved value.
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From: Maryland
Originally posted by Blue_350Z_Track
You should be able to hit a 13.7 with the stock exhaust. I did it with just a K&N panel filter.
Damian
13.715 @ 102
You should be able to hit a 13.7 with the stock exhaust. I did it with just a K&N panel filter.
Damian
13.715 @ 102
in addition, i think my car is one of the factory weaklings as opposed to a factory freak, which some of you running mid 13 stock may have. there is not an issue with my driving this i know. even powershifting it really won't gain much and def. gains no mph ever.
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