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Watermouse

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About Watermouse

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    Rank: RB20DE

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    Male
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    Lake Macquarie

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  • Car(s)
    R34 GT-T
  • Real Name
    Ian

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  1. When I had my Forester XTL I was on OzFoz everything I needed to know was there and very knowledgeable blokes same as here
  2. Heres another good explanation from Venom Exhausts from Aust Ford Forums Quote: Originally Posted by webbiegareth Yeah I'll wait for XRCIST's feedback - it's more curiosity than anything My theory was that the Venom 400CPSI cat with the 4" body was bigger than the stock cat, and even with the same CPSI, the greater overall volume inside would allow for a bit more airflow. I was happy getting a replacement stock ceramic cat (the full thing with the engine pipe etc), until I saw them on ebay for $300... ugggh. Or are they cheaper than that normally? If the Venom cat with 400CPSI is better than the stock cat, and almost half the price, I'll definitely get it. Hey mate, you are absolutely correct Even though 2 cats are 400cpsi, they wont have the exact same flow properties. The main factors apart from the cpsi rating that determine flow are the body size, substrate length and inlet/outlet size. A larger diameter substrate will allow more flow than a smaller diameter version, assuming all other specs are the same. The substrate is the point of restriction that slows the gases down, the more passages you can provide through this point for the exhaust, the better. The other thing you have to remember, the standard cat is made with a ceramic substrate, which is much more prone to melting and breaking internally than a metallic version. Metal versions can withstand higher temperatures and richer air fuel mixtures, and those with larger diameter substrates (assuming all other specs are the same) work even better, as the larger surface area handles the heat more effectively. Thats why i recommend the larger body ones for turbocharged vehicles, as they are usually tuned richer at WOT than NA vehicles. The other key factor that determines flow is the inlet/outlet diameter. To put into perspective, a straight section of pipe can flow roughly 115 CFM per sq inch of area. With that in mind a 2.25" pipe can flow 408cfm, a 2.5" pipe 509cfm, and a 3" pipe works out to be 747cfm. The larger inlet/outlet diameter allows for more flow so you can therefore have have the same emissions compliance but still gain in net flow. So you could even fit a 3" 400CPSI cat on your car and then taper the pipe down after the cat to suit the exhaust, and still be better off flow wise than the standard 2.25" 400CPSI cat. The other factor is substrate length. All of the Venom Cats have a 10cm long substrate. I havent measured the length of the substrate in a standard AU Falcon Cat but i can imagine it would be much longer. It goes without saying that shorter is better in terms of flow. In regards to emissions compliance... You are right, a 100CPSI cat will not pass an EPA test (assuming the use of normal gasoline). Some brands may claim Euro 3 emissions standard on their 100 cell units but that doesnt mean it will pass the Euro 3 test. It may have the right makeup of precious metal content which is in line with Euro 3 standards, but the fact is the 100CPSI substrate just doesnt have the density to slow down and filter the gases effectively. The 200CPSI units are much better, but then again some do fail (This can relate to the substrate length discussed before). All of my 100 and 200 cpsi units have a Euro 2 coating on them. The 400cpsi versions are made to Euro 3 standards, which is applicable up to 2009, (more than adequate for AUs). You have all the strength benefits of a metal core cat with the capability to pass emissions. Again you do have to remember that emissions compliance is also affected by other modifications too. Hope ive answered your queries, if you need any other info just let me know George __________________ VENOM EXHAUST WORKS 0402753146
  3. Found this in Fordmods in a google search for venom cats, thought I would be of some interest as the reply is from their supporting vendor from Venom Cats EVL098 wrote: I run the venom cats on my Fairlane when I had it and they were great. I am also running Venom cats on the XR8 now. Cannot fault them for the money. While yes 100 cell isnt legal to the EPA the law in NSW is you must have a functional cat convertor if you car is 86 or newer. It doesnt say anywhere how well it has to work it just has to be functional. As far as the EPA goes changing a cam is just as illegal as running a 100 cell cat. A cat wont clean everything up and if you go with a bigger cam it hasnt been tested and proven to comply with ADR's which is where the EPA gets you. Tuning a factory ECU with a J3 is the same story. If the EPA want to do you they will one way or the other. I highly doubt many members cars on here are under the 90db required to pass the EPA either. If you knock the guts out of a cat there is no excuse you could use and you will get raped if they ever checked it. Running a 100 cell you can plead ignorance and just get a notice to change it. Providing the cat is functional you should be fine. Spot on The big issue is with knocked out cats, as long as you have a functioning catalytic converter then you are ok from a roadworthy perspective. EPA on the other hand is completely different, and while the cat may be compliant (200cpsi or 400cpsi) like EVL098 said, it does depend on other modifications you have done, cam, tune etc as these will all change the emissions output.The smell is a tell tale sign of decat (and a 100CPSI but not as bad). The 200CPSI is much cleaner.Most tend to go for a 100CPSI as it is higher flowing and does give a little more volume than an equivalent 200cpsi. Whether that translates to more power though depends on your application, on an NA 6 the flow difference will result in a negligible gain, the difference is greater for a Supercharged/Turbo (especially Turbo) car. The DOHC motors though can sound a little raspy/tinny with a 100 but that is a trait associated with a lot of DOHC 6s and 4 cylinder vehicles when you open the exhaust up, muffler choice in this area helps immensely.Also most 100CPSI cats will only be Euro 2 compliant. You can put a Euro 3,4,5 or even 6 coating on it but at the end of the day the substrate just doesnt have the density to be able to filter the gases effectively (unless it has a ridiculously long body).The balance is between emissions and flow. If you are concerned about emissions the 200CPSI cats are great and offer the best balance between flow and filtering and on most applications will work perfect. Especially on a V8 running 2 cats as the exhaust flow is split, although the 100s do sound better on the 8s haha We also have the 400CPSI cats and they all have a Euro 3 coating and are legal on newer model cars.If anyone has any concerns or queries just drop me a msg, more than happy to help
  4. Hey mate, as I said, I mean no bad to you and was never intending to put you in a defensive posture Your dedication to research and development of our Nissans is highly admired and respected Disregard my last post, I must not have explained myself well enough All the best Tao ??
  5. Sounds good for the price The concern I can see just quickly looking at it is that there is no integrated GPS, so Im gatherithing its using multiple mobile phone base stations (normally 2, lucky 3) that triangulate on sim signal to indicate estimated location. This fails in accuracy for a number of reasons when something valuable is at stake, but I guess u can add a gps in the port but then price/value changes
  6. Hey welcome Chesney ? Very nice car mate. There are some very knowledgeable and friendly guys here that will surely help,you out with your track car and I hope you can give a little back to SAU cheers,
  7. Ive been watching yours and discopotato's posts, I'd be happy with the 7163 as 300-320kw with insane street response is right where I want to be but some warned about surging because of the .80 hot side maybe being a bit small. This is were Im beating my head against the wall like you, trying to pick the right turbo and A/R cause that now brings the 7064 into the picture as well. I have to go low mount I/W to try to be as much stealth as possible Thanks for your input
  8. Thanks very much buddy, Im sure that will help a few of us ? Sooo everyone, my next dilemma is go T3 .83 A/R or T4 .92 A/R with adapter plate, has to be internal gated. Any input would be greatly appreciated? Its an unopened 25neo that will have ARP 2000 head studs at this stage. The power bracket Im after is great street response from about the 2,800-3,000rpm mark to 120kph. If Im looking at the wrong turbo please chime in thanks
  9. Any chance you can post those pics please mate? Looks like Im going a 7670 on my RB25 from whats been said, so I need to know how that will sit in my 34GTT low mounted on the stock manifold that I will mod for split to go TS
  10. Hey Bailey Im guessing your new to forums. Mate before you get smashed can I give you some advice? It is etiquette to do some searching before you post up a question, use google to search this forum as it works better ? Of course if you cant find what you need, post up. But Jesus and his deciples were toying with RB's long before you and I started playing with them so 9 times out of 10 it will have been covered 50 before. hope I got in before the less subtle deciples just gave you both barrels oh and you will find your answer ???
  11. Sorry, I keep,forgetting and lapse into Australian
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