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Old 29 May 2005, 09:49 PM   #1 (permalink)
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Downpipe question

Hi,

Can anyone explain the difference(s) between an 'open necked' decat downpipe (oval opening) and the 'normal' decat downpipe (round opening)?

I assume the 'open necked' version is the better performer but by how much?

Any info much appreciated

Cheers,

Mickey.
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Old 30 May 2005, 08:32 AM   #2 (permalink)
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Hi mate

The differences in the 2 downpipes are

Twin Dump down pipe = has an outlet for the Tubo gasses and an outlet for the wastegate gasses. The 2 pipes usually join slightly farther down the pipe. This means that the gasses are seperate when they enter the exhaust. Supposed to be the more efficient but a number of owners have experienced serious boost spike problems.

Open Mouth down pipe is basically one large hole that incorporates both the turbo and wastegate gasses. They all disappear down one hole so to speak which I guess could be argued isn't quite as efficient but does seem to create a lot less problems with overboosting etc.

Hope this clarifies
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Old 30 May 2005, 09:06 AM   #3 (permalink)
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Thanks Nelson, knew you'd have the answer :wink: .

What about the ones that have a round closed off opening? Just a round pipe and a flat flange at the end.

Are these ok to use? Just not as efficient as the 2 types you mention.

Thanks again,

Mickey.
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Old 30 May 2005, 10:17 AM   #4 (permalink)
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No probs m8

The ones with one of the holes blocked up is basically exactly the same as the oem one that is currently on your car The main difference will be no Cat in the way to restrict airflow. However if you are running standard ECU then I would suggest the open neck version as you can get considerable gains in power by going for this
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Old 30 May 2005, 06:58 PM   #5 (permalink)
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Thanks mate, you're a star!!

BTW, I have had your old centre section fitted for a while now, and coupled with the ScoobySport rear box it sounds awesome!! 8)

Also got the Green filter in place, just the decat downpipe to go and then thinking of a remap.
I've heard/read good things about the TEK3 remap, can I ask what your opinion is??

Also, what sort of power should I be looking at after the remap?
Finally, how much benefit would new headers make (before the remap),
(UK MY00, only engine mods as above)

Thanks again mate,

Mickey.
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Old 30 May 2005, 07:13 PM   #6 (permalink)
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Hi Mickey

Nice one on the Exhaust the Scoobysport sounds the dogs danglies with the Ninja Centre in place

A Tek3 Remap will be a worthy addition. What year of Scoob do you have mate and what model is it ?? If its a MY99/00 Classic with the TD04 Turbo then you will probably get no more than 270-280BHP and similar torque, this is the Turbos limit. However the car will have a different power delivery and will be all round more powerful. I wouldn't really bother with the headers unless you are thinking of going for a larger Turbo etc. With a different Turbo, Headers, Panel Filter, Full Decat then there would be no reason why you wouldn't be looking at around 300+ BHP. Then you could start to consider a FMIC but I do believe the TMIC is good for about 300-320BHP. Oh yea and I would chuck a new fuel pump in too as the existing one might be stretched with the extra power.
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Old 30 May 2005, 09:19 PM   #7 (permalink)
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Nice one, cheers Nelson, mine is indeed a MY00.
Any other types of remaps worth considering?

I will be well happy with 270-280 Bhp for the time being!!

BTW how does your new motor compare with your Scoobs? It certainly looks the part!! 8)

Cheers,

Mickey.
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Old 30 May 2005, 10:13 PM   #8 (permalink)
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To be honest Mickey a Tek3 remap from Bob Rawle would be just the ticket for good safe power

The guys a genious when it comes to mapping scoobs and I have only heard good things about him. You could go for a replacement ECU - Gems is a good one but expect to be paying more in the sum of 1000-1500. With this setup the Mapper can do away with the MAF sensor (which are weak on the MY99/00's) and can also give you AntiLag if thats what you want. If I were in your shoes I would go for a Tek3 A good safe 280BHP would be very nice 8)

As for my new motor - enjoying it more and more mate. I really did miss the Scoob at first and I am slowly getting used to not waving to Scoobs that I pass due to some of the rude remarks I get in return... However having now used the power and handling on a few occassions its mind blowing mate I have some serious mods planned for this one just gotta try and get the missus to stop screaming slow down all the time 8) ops:
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