NC Catted Header

[LuckyCat]

OK so the consensus here is:

A catted header in OZ is a waste of time. A simple reflash would be more beneficial.

Better option for exhaust then would be a complete roadstersport system?

OR just the roadstersport header, and wait for the midpipe with twin cats being developed here?

Thanks for the discussion !

So the final advice is....

cheers
Chris

[wozzah1975]

OK so the consensus here is:

A catted header in OZ is a waste of time. A simple reflash would be more beneficial.

Better option for exhaust then would be a complete roadstersport system?

OR just the roadstersport header, and wait for the midpipe with twin cats being developed here?

Thanks for the discussion !

So the final advice is....

cheers
Chris

IMO the catted header is a waste. Whilst I am no expert with hands on experience with the NC factory ECU settings I would think that the benefits of an ECU reflash and nothing else would also be limited. There are exceptions to that rule with certain makes and models, but I would say after looking at the factory header design it would be my first starting point in modification to the car. The fundimentals of making power haven't changed, the engine needs to breath and scavenge correctly first, a reflash simply can't do that. The only thing a reflash will do is clean up less than ideal or conservative fuel and igntion tuning, providing it was not ideal to start with.

In my experience in most cases correcting obvious breathing issues is far more beneficial than correcting ECU issues. More often than not with the ECU technology this day and age when you make an engine breath better the ECU automatically compensates anyway, so it's win win.

I would start with a 4-2-1 header instead of the GWR 4-1 item. Use decent cat and a 2 1/4" system with everyday ordinary straight through glass packed mufflers. I think straight up that will make the car respond well. You don't need to spend a fortune on fancy branded stuff to get something that works, it just needs to be well executed by an exhaust shop.

Cheers
Warren

[LuckyCat]

So: who? (not knowing any decent exhaust shops)

chris

[wozzah1975]

So: who? (not knowing any decent exhaust shops)

chris

Where are you located? I'm sure someone on here will know of a shop close handy

Cheers
Woz

[Sailor]

Chris, You are welcome to drive my car with just a 4:1 header, flash and RS muffler.
The setup is extremely well researched and developed.
Look at the performance of Ralph and Phil using just that...although Ralph may have a midpipe as well.

[NitroDann]

There is a HUGE difference between an off the shelf out of a box 50 state legal system and proper gear custom built for the job, and no that difference isnt price (I bet proper custom would be cheaper or on par), its performance.

Dann

[Charlie Brown]

Can I just chime in here with a few points.

I mean no disrespect to posters who aren't NC owners but there are a number of important points that need to be made about the research and development that's gone on over the last 7 years.

First up the MX 5 Cup cars since 2007 have run 4:1 DC headers.
Goodwin has tried and tested many combinations of headers to determine what's best for us mere mortals and has come up with 4:1.
IL Motorsport in Germany makes 4:1 & 4:2:1 headers.
One of our Club members has the IL 4:2:1 headers and has suffered problems when turning on of all things, his AC. His 4:2:1 doesn't perform as well as the 4:1 systems from other manufactures.

Flashes on stock NCs have been dyno tested to give approx 5kW extra.
A 4:1 header will give you around 7 - 8kW with the rest of the exhaust system stock.
A Goodwin mid pipe gives just 2kW, free flowing muffler another 3 - 4kW.
Combine a 4:1 header with mid pipe, sport CAT, aftermarket free flowing muffler and a flash and you end up with around 108 - 110rwkW.

[NitroDann]

Theres no dispute that the system is better than the atrocious stock system, whats being said is that a system made compromise free especially for a specific purpose will perform better for that purpose.

The headers tested for example all have the stock flange compromise which is ridiculous because its position is designed for ease of factory fitment of a stock header which has a very large diameter cat fitted. Its not designed to finish after a set of properly designed 4-2-1 long runner headers. Comparing a header designed to fit into a horrible stock system to a full flange-to-exhaust-tip redesign isnt comparing apples to apples. Im talking abut a redesign that removes the compromises that do not allow, for example, a 4-2-1 header to perform like it should.

Dann

[Charlie Brown]

Goodwin does offer a header and revised mid pipe with a flange position well back from the stock position.

It's still a 4:1 exhaust system.

http://www.good-win-racing.com/Mazda-Pe ... -1078.html

[wozzah1975]

Can I just chime in here with a few points.

I mean no disrespect to posters who aren't NC owners but there are a number of important points that need to be made about the research and development that's gone on over the last 7 years.

First up the MX 5 Cup cars since 2007 have run 4:1 DC headers.
Goodwin has tried and tested many combinations of headers to determine what's best for us mere mortals and has come up with 4:1.
IL Motorsport in Germany makes 4:1 & 4:2:1 headers.
One of our Club members has the IL 4:2:1 headers and has suffered problems when turning on of all things, his AC. His 4:2:1 doesn't perform as well as the 4:1 systems from other manufactures.

what you need to be comparing is the "ideal" 4-1 compared to the "ideal" 4-2-1 on the same engine. I would suggest on the above that not enough time has been spent on the 4-2-1 design which is usually the case. 4-1's will always yeild more top end power, but the sacrifice in mid torque and power is detrimental to the overall curve. The type of car they are fitted to is irrelevant, whilst the recipe on the size and lengths changes the overall effect is similar. The only time you would consider a 4-1 is if the engine spend all of it's time at the upper levels, eg: a track like Phillip Island

Flashes on stock NCs have been dyno tested to give approx 5kW extra.
A 4:1 header will give you around 7 - 8kW with the rest of the exhaust system stock.
A Goodwin mid pipe gives just 2kW, free flowing muffler another 3 - 4kW.
Combine a 4:1 header with mid pipe, sport CAT, aftermarket free flowing muffler and a flash and you end up with around 108 - 110rwkW.

you also need to be carefull with these quoted figures. Alot of the time it's not as simple as adding the increases up. Manufacturers of this gear are very smart in how they quote figures. For instance and ECU flash may yeild it's maximum increase at 4500 rpm of 5kw, but may be not as much at say 7500rpm. Same with making changes to pipes etc. They will quote an increase, but it may be at a totally different RPM point. You need to be able to study dyno graphs carefully when it comes to this, as the figures are easily misread and fudged

Alot has been learnt about header design the last 10 years or so. With very smart collector design and sizing 4-2-1 or tri-y designs are making a huge comeback (if you ever get a chance to look at a V8 supercar header note the changes in them over the last 10 years!) At the power levels spoken about here I would not even consider a 4-1 header. Mid range torque is far more useful than top end power in 90+% of applications, including race cars, you just need to pick out the right header.

Cheers
Warren

[mx5racing]

To end the speculation regarding fitment of the GWR catted header for RHD applications we sent a RHD steering rack to the US to check once and for all. Brian Goodwin has just confirmed the Roadstersport catted header does not clear the steering shaft.

Obviously the Roadstersport MAX header does - http://www.good-win-racing.com/Mazda-Pe ... -0080.html

[Sailor]

OK...So now it's time for you to get a high flowing cat ready to slot into the mid pipe so supercharged NCs can breathe....legally

I'm in cause I really don't want to pull the header to pass an emissions test.

[Charlie Brown]

For those desperate souls still wanting a catted header, and I don’t know why, it looks like IL Motorsport have produced one for the RHD NC’s and it can be found here:
http://www.mx5parts.co.uk/stainless-ste ... -2932.html
I’d still check that it fits before ordering.

[wozzah1975]

YUCK !!. That looks bloody horrible. Lengths all over the shop and the collector looks very ordinary!
Woz