Scotte

Subtech Downpipe Review

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Hi, I wanted to outline my experience of the Subtech Legacy Downpipe.

You can see the pipe and deno chart on this auction. Max boost is 11.5psi

http://www.trademe.co.nz/motors/car-parts-accessories/subaru/engines/auction-440662123.htm

My car is 2003 BP5 Legacy Wagon GT (2L turbo)

I had the factory downpipe replaced with a Subtech Downpipe a couple of months ago now. I also had the airbox modification done (they remove the silencer and put in a feed down to the bottom of the car.)

The downpipe is cat-less but the two O2 sensors plug-in in the same position as the factory downpipe.

Before i put on the downpipe i always felt when driving generally or cruising that there was some resistance, like the handbrake was slightly on. The power didn't really kick in until 2800rpm and i would often drive around in sport mode so that it felt more powerful. Going up hills i would often flick it down a gear on the triptronic to get up a hill easier.

The overall result of installing the downpipe is a big increase in power. Noticeably the boost comes on much quicker down low. The car feels much better to drive in standard mode and it glides up hills compared to before. So for general driving it is a much more pleasent car to drive. If you put your foot down there is heaps more power too. It really is quite a bit quicker. Start using the triptronic on the highway and its quite fun.

I didn't like the sound of the air box modification and got it changed back to factory (has a high flow filter though). Haven't noticed any drop in power from putting it back to factory and now it sounds better too. I wouldn't recommend that mod. Waste of time and money.

Noise

Because the downpipe is catless it is quite a bit noisier. Down low and up high the sound is fine, but accerating from slow speeds it can be quite loud, a raspy sound, which can be unpleasent.

Rest of exhaust

Subtech say they are developing a rest of system exhaust which will address some of the sound issues. Although this will be another $800-$900 dollars.

Mixture

Because the sensors are in the same place as the factory Subtech tell me the mixture will be fine and that it won't run lean or rich.

Tuning

Subtech also say tuning isn't require for this modification.

Questions

I really like the extra power and torque. But am concerned about a couple of things:

To reduce the exhaust sound i was thinking about removing the factory resonator (after the downpipe) and replacing it with two coby resonators running in-line. Is this a good idea?

I want to keep it quite quiet, so quite keen the keeping the factory mufflers and trying to sort the sound with resonators.

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How many KMs has the car done and has the cat been changed because as far as I knew, they wore out eventually so you mightn't be changing your earth kill ratio at all?

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Not to point out the obvious but if you are that concerned about the enviroment you should not have bought a gas guzzling turbo car ;)

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This is gonna spark a massive debate now lol.

It's interesting because for having a catless downpipe the turbo is less restricted. Insurance companies recognize this mod as a turbo killer as it supposedly overworks the turbo. - now I would like to say it seems like utter bull$4!t excuse to make premiums more expensive.

I see it as it makes it easier for the turbo to do what it does.

As for your exhaust- Now here's the thing, you change that and you won't know 100% what the outcome will be. What if you don't like the sound, you've just wasted money.

You can go to one of the preferred exhaust contacts club sub can refer you too and they can clarify what setup would give you the balance of noise and performance.

Now for this, imo I suggest getting a mild tune for.

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 reaperblitz said:

This is gonna spark a massive debate now lol.

It's interesting because for having a catless downpipe the turbo is less restricted. Insurance companies recognize this mod as a turbo killer as it supposedly overworks the turbo. - now I would like to say it seems like utter bull$4!t excuse to make premiums more expensive.

I see it as it makes it easier for the turbo to do what it does.

As for your exhaust- Now here's the thing, you change that and you won't know 100% what the outcome will be. What if you don't like the sound, you've just wasted money.

You can go to one of the preferred exhaust contacts club sub can refer you too and they can clarify what setup would give you the balance of noise and performance.

Now for this, imo I suggest getting a mild tune for.

that sounds like bullshit to me... never heard of a insurance company adjust your premium becasue youve changed the downpipe... ???

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Ask Janssen Mechanical Warranty as well as State.

I understand from the mech warranty/insurance pov but State don't like mods on vehicles and can decline you and send you to NAC

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I'm not too worried about the insurance side of it.

Where is the list of ClubSub recommended exhaust shops.

True to the ealier comment, i do prefer performance to the environment : )

How do i post a pic on here?

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Cheers for posting this write-up! Im actually in the position atm of deciding whether or not to buy and install this downpipe. Was also looking at the airbox modification but sounds like i might just skip that and only do downpipe. Bit of extra power is always nice

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Yes it is quite a bit of extra power.

Be aware though its a lot noisier too.

What are you thinking of doing with the rest of the exhaust?

Are you considering a tune at some stage?

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Drove out to Beachlands on Friday night and back on saturday morning.

On the open road the extra power is massive, such a good drive with the new downpipe.

The car is running perfectly and im seems to working fine on the factory tune. Will see about a ecu tune next year maybe.

Am going to wait and see what the rest of the Subtech exhasut sounds like before doing any other mods there.

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I also got this downpipe installed, had it done sometime last year. I'm loving the gains but the raspy sound at times does get to you.

Sounds like a hollow can, doesnt really match the look of the car IMO. Having said that its not too loud, and the DP also makes the turbo more audible, which is always nice :D

I'm also keen on the exhaust, I should be popping in this week and will enquire about it.

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Downlow on the Downpipe.

Yesterday Dave from A1 Exhaust in Glenfield (09 441 4635) put a high-flow cat converter into the end of the Subtech downpipe. The result is fantastic. The car is a lot quieter. It is louder than stock, but actually sounds really nice, much nicer than the stock sewing machine sound. The engine sounds deeper and there is a smooth whoosh when you put the power on. It just sounds fast, not loud. It also feels a bit smoother to drive. Nicer.

Its a win/win situation, I was noticing running a cat-less exhaust would be a bit smelly when you pulled into the garage. Un-catted exhaust smells terrible. No wonder - its full on lots of toxic gasses! Now the exhaust hardly smells, the cat converts most of it to CO2.

I reckon driving without cat converter is a bit of an up-your's to this planet we live on and considering how good some of the hi-flow ones are there no excuse to do it. If you're want to gut your car of cats think about it and realise exactly what you're doing - aggressively polluting the air quality, which if you live in Auckland is definitely an issue! There are so many car's belching out shit in this city, its disgusting!

Dave did an excellent job. He used an Autobend Oval hi-flow cat and put it at the end of the downpipe before the flex-joint. Hence the second half is the exhaust is still factory. If ever necessary, for whatever reason the old downpipe can be refitted at any stage to return the to factory spec.

The cat actually sits in the exact position of the second cat on the factory pipe. Just after the second O2 sensor. The O2 sensor has gone back into the exact factory position as well.

I actually believe this is how the product should have been sold in the first place, or at least have a price option for it. It would make it more expensive, but i think some people would be willing to pay for it, just for the way better sound alone.

The overall result of this downpipe now is awesome, heaps of extra power with a nicer sound. The car is so much more driveable, especially when you are just cruising, it has so much more down low torque. If you've got one or thinking of getting one i would recommend the retro-fitted hi-flow cat.

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Thanks for the info! Any chance you could upload a youtube video or something so we can hear? I've got a stock bp gt so am curious to hear the difference!

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Good on yo for being planet friendly, but the whole reason people usualy go to an aftermarket down pipe is to remove the cat for more flow and more power, thats probably why they dont offer a catted option.

Even with a high flow cat it will still have less power than without a cat at all.

It not illegal to remove them in NZ yet, but it will be in the near future when NZTA finally catches up on the rest of the world.

As for getting it reflashed/retuned you dont need to if you dont want more power ontop, the way the factory system is set up it adjusts air/fuel mixtures automatically for the extra flow.

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yea good info bud!

If you are worried and if it were me.. a cheap option (around $75) is to just get a on road Air/fuel Ratio test just to make sure its not lean under boost or WHY.

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 Scotte']I reckon driving without cat converter is a bit of an up-your's to this planet we live on and considering how good some of the hi-flow ones are there no excuse to do it. If you're want to gut your car of cats think about it and realise exactly what you're doing - aggressively polluting the air quality, which if you live in Auckland is definitely an issue! There are so many car's belching out s*** in this city, its disgusting!

That's kind of an exaggeration; air quality in a given area is admittedly caused by cars etc, because it's constant output over a constricted area (Los Angeles being the stereotypical example) and I will not dispute that at all. On the whole, however, eating meat is a much bigger "up yours" to the planet by far than cars.

http://www.un.org/apps/news/story.asp?newsID=20772&CR1=warning

 
When emissions from land use and land use change are included, the livestock sector accounts for 9 per cent of CO2 deriving from human-related activities, but produces a much larger share of even more harmful greenhouse gases. It generates 65 per cent of human-related nitrous oxide, which has 296 times the Global Warming Potential (GWP) of CO2. Most of this comes from manure.

And it accounts for respectively 37 per cent of all human-induced methane (23 times as warming as CO2), which is largely produced by the digestive system of ruminants, and 64 per cent of ammonia, which contributes significantly to acid rain.

I'm no greenie vegetarian advocating everyone stop eating meat, but saying that cat-less exhausts kill mother earth is a bit OTT. As car enthusiasts a lot of us do end up de-catting our performance cars, but most of us won't do it to our daily drivers which get a lot more usage/km's/gas output potential. A tree being cut down to produce one day's printing of the nz herald/dompost/your local paper probably does more harm to the planet than decatting a car that only does a few thousand km's a year.

IIRC, the coal/gas/etc plants used to provide energy for electric trains for example produce more greenhouse gasses than if everyone drove (not true in areas where a large proportion of energy generation is from hydro or electric, but the north island of new zealand is not one of these). Again, not advocating everyone driving their cars everywhere, but introducing perspective.

[quote name='Scotte said:

I actually believe this is how the product should have been sold in the first place, or at least have a price option for it. It would make it more expensive, but i think some people would be willing to pay for it, just for the way better sound alone.

A trend I've noticed with american products is that manurfacturers do actually do this, selling a "with-cat" option and a "no cat" option

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lols well put rob.. found the post way OTT myself.

cats only last fek all time anyway so most are 'dirty polluters' anyway with their cats still in.

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Could try to do a video at some point. If i do i will let you know.

If you're in Auckland you're welcome to come and listen in person.

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MercuryFree, i understand where you're coming from. You're right a lot of greenhouse gas emissions in NZ are from Agriculture.

But, my car is my daily drive, ill probably do 20,000kms in it this year. Half of it commuting into Auckland city in rush hour traffic on the motorway.

I notice most of you guys commenting on emissions are from Wellington. If you did the drive i do along the southern motorway in Auckland every morning you might understand more of what im talking about. Its literally filled with cars and trucks and pumping out smoke and fumes. If you drive with your vents open you will be feeling sick by the time you get to work. I find it amusing that NZ promotes itself as so clean and green when compared to overseas our car fleet is terrible.

Just saying I'd rather not be contributing to the problem.

For me i am just happy with the result i've achieved and like i said its a win/win, less noise and less pollution.

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