I agree to what Eric (MADFTO) said, & I've also got RPW extractor. I've already gave my good & bad points of the product, so i don't have to repeat myself here.
But what i like to point out are that not everyone had the time & money to do two dyno everytime they put a mod in. Which what steve had ask everytime someone put a review on product (especially RPW).
Don't get me wrong, I definitely agree that we need to proof what we said, & not just some "feel", but how realistic would it be that people can do two dyno for every mod???
I think thats the original point GWIDO were try to make.
ONCE AGAIN, I'M NOT ON ANYONE SIDE, I'M JUST GIVING MY POINT OF VIEW, AS THIS IS A PUBLIC FORUM.
DISCLAIMER: The above text is the personal opinion of the author and does not represent the indisputable truth. The author is not responsible for any deaths, injuries or mental illness caused by the above statments.
But the question I would like answered is whether or not the RPW extractors/downpipe combo has the same hissing noise experienced by the UAS counterparts??
Hmmmm, I've never heard of that happening before I don't think =P
It sounds wierd =)
What size piping do you have after the cat?
Just sounds a bit wierd, sounds like some sort of turbulence at lower rpm. I don't know though, it's always hard when you can't hear it for yourself =P
Between 4000rpm and 3200rpm, there was a 'bees in a can' sound coming from the exhaust system.
I wrapped the flex joints in header wrap, and the bees got much much quieter.
- Rich
i do notice the hissing noise around that rev range, but dont notice anything on throttle off... what is this header wrap? and where can i get it from?
oh nevermind i saw the other post
Disrespect is easy. Respect is the difficult road to take.
GWIDO wrote:I dont seem to get that noise from my GPX.
It is manual GPX, RPW extractors, throttle body and CAI, FPR.
There is a slight noise from the CAI though.
The only mod i'm different to yours is throttle body, while i ported & polish, but yeah my CAI is bloody loud after the extractors. Is like a vaccum cleaner on the lowest power I guess is a good thing that its sucking lots of air
DISCLAIMER: The above text is the personal opinion of the author and does not represent the indisputable truth. The author is not responsible for any deaths, injuries or mental illness caused by the above statments.
Yeah i know what you mean with the pod filter, but this is much louder then just with just pod. Heheheh then again i guess u use to it, since you had your extractor & pod for a very long time now ehehehe
DISCLAIMER: The above text is the personal opinion of the author and does not represent the indisputable truth. The author is not responsible for any deaths, injuries or mental illness caused by the above statments.
The sucking sound occurs because the engine is requiring more air and in turn more air is being sucked through the air filter. As a larger volume of air is sucked through the filter the speed at which it is sucked through will increase. As the speed of the air increases it becomes audible, producing the sucking sound, it's the same sort of concept as only being able to hear the wind when it is blowing a gale.
With increased air speed comes more turbulance and likewise less efficiency with the air filter. i.e. more dirt and stuff will get sucked through the filter because the speed at which it is travelling is higher.
So if you're getting this sucking sound, it may pay to get a larger air filter. The increased surface area will allow the same amount of air through, but at a lower pressure, thereby decreasing the amount of air turbulance and increasing the cleaning efficiency of the filter. The sucking sound will also decrease.
took my pod off, totally caked in crap. guess that would have something to do with it. can't wait to see some performance improvement when its clean. need to design something to protect it a bit me thinks....
so from what you are saying ruchi, there is a restriction somewhere in the UAS downpipe that is making it hiss? or did the flex joint thingy totally solve it Rich?
The RPW extractors have a single, very large, maybe 3inch, flex joint in them that is extremely hard to make flex. Maybe the downpipe could be redesigned to include this in the next production run. From what I've seen the down pipe has two quite (comparitively) small flexs, is this right?
GWIDO wrote:
so from what you are saying ruchi, there is a restriction somewhere in the UAS downpipe that is making it hiss? or did the flex joint thingy totally solve it Rich?
The two flex joints mean that each engine pipe (post extractor) can flex whichever way the engine moves....
there isn't a restriction that we know of... we actually have a few larger diameter ones floating around from prototype testing with different ID's to see if there was a gain - there wasn't. (these would be perfect for a turbo FTO not a NA FTO)...
the hissing noise is a reverberation that is accentuated depending on the aftermarket exahust that a car has... some have none some have heaps....
the engine pipes were designed using standard calculations for exhaust velocity at varying engine RPM to design a system that was as efficient throughout of much of the rev range as we could make it...
it's easier to design one for a car that spends most of it time above 400RPM hard to develop one that works from 750 - 8500...
sorry ruchi, was using your explanation to try and explain to myself why the uas downpipe makes the noise Richardh was talking about. guess i got yous lost in my train of thought.
What i was trying to say was that if a pod makes a noise due to a restriction, then would extractors do the same thing? ie is the noise in the downpipe due to a restriction??
generally speaking, wherever there is a restriction pressure will increase, however with the UAS piping the hissing issue occurs when people back off on the accelerator (big pressure decrease) not when they are accelerating (big pressure increase). So I don't believe there is any restriction issues with the UAS pipe, in fact it could well be the reverse, perhaps it flows out so well that when the pressure does decrease (foot off the accelerator) there may be a void or low pressure that creates suction.
I posted this same message in another thread covering this same topic, but as there are multiple threads going, I'll post it here too...
in looking at the dyno graph for the UAS pipe, the biggest difference is at the top end. So in short, if you want more pickup in the mid-range go for the RPW extractors or if you want more in the top end then go for the UAS pipe.
This also quells any issues as to which one is better, as they work in different rev-ranges.
I guess is a good thing that its sucking lots of air 
hard to develop one that works from 750 - 8500...