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Discussion Starter #1
Been doing some research on exhaust and gains as dynoed in Australia.

I moved these from the other site.

There were others but I chose to omit those because they compared more than just the cat-back system.

If you find more or have other systems please add, but ONLY comparing before & after dyno's of the cat-back exhaust system.

This will limit any future confusion for those wanting qualified numbers.

At the moment I only have the High-Tech systems. If anyone has an APS cat-back system with dyno please add.

This should help those contemplating an exhaust system purchase.

cheers
 

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Discussion Starter #5
For those newer to exhaust modifications:

From the above, the average with the High-Tech system is 17.7 rwkw increase.

The High-Tech system costs $1800.00 (NSW phone quote)

***Looking at $ per kw, that equates to $102.00 per kw. for High-Tech

Comparing APS system. Dyno chart below of mikenb's zed at Autotech day in Sydney Feb 2005 shows 11rwkw increase.

The APS system costs $1900.00 (NSW phone quote)

looking at $ per kw, that equates to $173.00 per k/w. for APS


No costing info for the Amuse system.

The above results will of course be different car to car, day to day, dyno to dyno, etc. Also baseline figures will vary from dyno to dyno. Saying that, each car was dyno'd on the same machine and day so the increase for that car at that point in time should be accurate.

As a guide on kw increase the above can help each decide on what exhaust will fit your need.


Cheers
 

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Hey dude.

If you're going to break it down into a kW/$ ratio, you might want to use a percentage increase in power rather than an absolute number. Otherwise, it really skews your figures.

The single APS test done was a very low power increase, and the HiTech equipped car pulled a similarly low peak power figure. The day it was tested was very warm and humid. Even running in shootout mode its not going to compensate for it entirely.

Having run my HiTech equipped Z33 against a APS equipped one on the only place it really counts, and that's down the main straight of a racetrack, there's nothing in it. Given that the cost difference of the items is so little, your kW/$ figures really jump out at me at being unfair.

If you were comparing a titanium exhaust to a stainless steel one the numbers would make sense, but not two (mostly) stainless steel items.


The other thing is those non-power costs. A titanium exhaust would lose a kW/$ comparison, but a power to weight / $ comparison would bring it far closer.

The APS costs a little more than the HiTech, but the APS' exhaust is of much better quality, a technically more elegant design (its one of only 2 true dual off-the-shelf Z33 exhausts I'm aware of and straighter than its competition), and provides more future proofing should you modify further.

Not knocking your efforts (I would have appreciated something like this when I was exhaust shopping, rather than making Google to the legwork myself), just suggesting how I feel we can help our fellow enthusiasts can make the best informed choice they can.
 

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Discussion Starter #10
I posted this info, but I don't own it, so anyone is welcome to add their own comparison, %, dyno's , etc. Like you said scathing, this will help those newer looking for exhaust systems.

Please feel free to do the above.
 

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Yeh i have to agree with scathing!

Mike this is one argument that just won't go anywhere! Simply because both exhaust put out about the same peak power. 2-3kw is negligible and well within the dyno's margin for error which i suspect will be pretty high.

So any discussion between Hi-tech and APS is kinda a waste of time.... regardless of whether it comes from the APS or HI-tech camp.

Everyone has a personal preference...i recommend people make a choice on sound and build quality.
 

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Discussion Starter #12
Yeah, I know this goes back a long way for you guys. Perhaps I should have posted the info in another way as scathing said, but that's hindsight. I think it is good however to put the relevant info ( and as more comes will try to keep it here) all in one place comparing all types of exhaust.

For those not familiar with dyno's take the above and whatever else comes in the future and digest it accordingly!

This little bit of a snippet on dyno's and comparisons etc will help:

"Accuracy", for many reasons, is a very relative term as far as dyno's go. Just how accurate is anyone's dyno? Take 2 motors, test them on 2 different dynos, one comes out at 100kw, the other comes out at 110kw, but they run the same lap times. Which dyno is "accurate"? Which one is giving you the correct numbers? Horsepower is simply a calculated number. Dyno 10 engines on the same dyno at 100kw, put them all in the same car one at a time, and they all run the exact same lap times. Is the dyno accurate? No, the dyno is however "repeatable". "Repeatability" is what you want in a dyno, test the same engine time after time and get the same results. Take one of the 10 engines from above, change an exhaust or a cam so you get 5% more power, run it against all the others again. It runs 5% faster, you re-dyno it and it still says 5% better, now you have an "accurate" and more importantly, a "repeatable" dyno. A couple hints: Always start your tests at the same engine temps and settings. Pay close attention to weather conditions. Get yourself a good barometer, thermometer, and humidity gauge, and enter the conditions into the program each time you make a run.

Hopefully this will make some happier!
 
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