Exhaust advice

[Cobblepop]

Hi all,

Firstly, please bear with me as I'm not the most knowledgeable when it comes to this stuff...

I would really appreciate your input into the exhaust I'm due to have custom made for my newly acquired Type S (stop laughing).

I was advised by someone at TDI North to go for a 3" diameter exhaust as it's important to allow an NA engine breathe, however, according to the exhaust fabricator this is pretty extreme... do you guys have any advice on ideal exhaust diameter?

Also, I was initially going for just a cat-back system but I've been thinking about getting a full system with high flow cat... is it worth the extra £££ for the performance gains? Essentially is there much difference between a cat back and a full system (with sports cat) performance wise?

Thanks for your help guys

 

[bxlheathsupra]

It all varies.. some engine like bigger diametre some dont. The type s engine is a k20 so may benefit from the larger system.
I guess it really comes down to future plans.. do you wanna go big power, are you planning any other mods?

I personally went 2.5 on my system for sound/ clearance and have no issues or regrets

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[Elliot438]

3 inch is the optimal for power mainly peak power but they do all drone and don't have much character compared to the more restrictive off the shelf systems.

I have the TDI North 3 inch catback with no issues, car made 252bhp with other usual bolt on.

Generally you are getting around 10bhp extra peak over the 2.5 inch systems. a 2.75 inch may be a compromise if you want power with a little less drone.

 

[Cobblepop]

Excellent, thanks for your advice gents.

In regard to a cat-back or full system, is it worth the extra expense? Are high flow cats worth it?

 

[Grano]

Full system with 3" for best power, but like said, it does drone. Where abouts in the rev range depends on the brand. Plus, you will need tuning if you do headers and a big exhaust.

 

[carl hammond]

http://www.itr-dc5.club/forum/index.php?/topic/47906-which-exhaust-setup/page-2#entry485429

3" + is generally better on a car that is FI and not NA, and a 3" system is 100% wasted unless you have the 3" manifold also, there is a reason 90% of the systems are 2.5-2.75" for these car's and I would rather quality over diameter of the pipe with perfect fitment and 0 drone ever over a few bhp (you may get if you go 3") but which wont be noticeable in the real world and when driving.

But if you like pub talk blagging numbers then 3" would be ideal as it may give you a few more numbers (depending on the dyno etc).

 

[Cobblepop]

Thanks gents, I'm definitely leaning away from 3" as it sounds unnecessary for what I'm doing with the car... in fact, the exhaust may be the only thing I do in the end.

I'm now a little worried about getting a system at all because if it requires tuning I don't really have the money for it.

If I was only concerned with the noise the car makes and forgot about bhp gains, what would you guys recommend? 2.5-2.75" cat-back or 2.5-2.75" full system with sports cat... and would either of these options require a retune?

 

[ollieh17]

3inch will just shift the power band and you will likely lose some mid range over a smaller diameter exhaust.Mid range is where you spend most time when driving

 

[carl hammond]

Thanks gents, I'm definitely leaning away from 3" as it sounds unnecessary for what I'm doing with the car... in fact, the exhaust may be the only thing I do in the end.

I'm now a little worried about getting a system at all because if it requires tuning I don't really have the money for it.

If I was only concerned with the noise the car makes and forgot about bhp gains, what would you guys recommend? 2.5-2.75" cat-back or 2.5-2.75" full system with sports cat... and would either of these options require a retune?

What do you want from it? all the DB levels etc are in the post I linked for you above as I did all the research. The kaki IMO sounds the best but is quite restrictive, the RM01A is more like OEM until on throttle then sounds great, the Mugen very similar. DC Sport I had on my car when I bought it was amazing sounding imo but the baffles went after 3 odd years (well started to go).

Josh at Torque GT is doing discounts on the RM01A which is the one I would recommend it over any other (and this is not because I have it) but due to the fitment, quality, looks, noise and so on. Also if you want to do any trackdays you can then run without worry and never need a bung.

 

[ollieh17]

How much difference is there between a Type S and Type R exhaust? The engines are quite different so peak power changes etc are likely to differ. Id go custom to account for any slight differences and being able to tune to sound to the car.

 

[carl hammond]

How much difference is there between a Type S and Type R exhaust? The engines are quite different so peak power changes etc are likely to differ. Id go custom to account for any slight differences and being able to tune to sound to the car.

I was wondering the same, maybe a stock OEM DC5 type R system would be suitable and beneficial imo, saves a lot of money and would be better still I think, if you want power then also look at an inlet manifold (DC5 R PBC one as they can be bought for cheap) unless you have one already etc

 

[ste01]

Don't bother doing anything, maybe just a back box if you're really wanting some noise.

If you are determined to buy a system, go cat back. Look at RSX base ones, they will be designed for the K20A3 so the likes of the 60mm skunk2 ones would be fine

 

[nails]

I wouldn't worry too much about the diameter, you are not going to see much in the way of gains regardless, so get the one that sounds the best. I would look at Spoon or Skunk2 if it were me, will the Spoon backbox fit the Type S? I am not sure.......

 

[Cobblepop]

Thanks again for the help gents.

I won't be going with an off the shelf option as I know a really well regarded fabricator (STG Performance in Wakefield) who builds excellent custom setups.

Essentially what I'm trying to achieve is a nice sporty sound when at high revs. The current exhaust sounds great at low revs but as soon as you push above, lets say 3500rpm it just seems to sound like any other car...

 

[Cobblepop]

if you want power then also look at an inlet manifold (DC5 R PBC one as they can be bought for cheap) unless you have one already etc

Just as a side note, is this the sort of modification which would require a retune?

I know I'm asking really elementary questions but I'm starting from scratch with my knowledge of modifications...

Edit: I think I've just answered my own question when reading about the RBC manifold on the eightspeed website, it seems you would ideally need K-pro....

 

[Crazylegs]

The challenge you have is that it's not a performance car you've bought sadly and again I reiterate, it's not a Type R. I feel like I'm having a pop at you which I don't mean to but you should have just got a Type R from the start. With an exhaust it won't make any real difference I have to be completely honest with you. You'd be better getting some better tyres, brakes or upgrade the suspension or sell it and get a DC5 or an EP3 bud. Sorry mate.

 

[Johngreen537]

Or bite the bullet and lick up a k20a or a2.
Much better gains for eventually the same cost.

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[carl hammond]

The challenge you have is that it's not a performance car you've bought sadly and again I reiterate, it's not a Type R. I feel like I'm having a pop at you which I don't mean to but you should have just got a Type R from the start. With an exhaust it won't make any real difference I have to be completely honest with you. You'd be better getting some better tyres, brakes or upgrade the suspension or sell it and get a DC5 or AN EP3 bud. Sorry mate.

This. If you want to improve performance upgrade brakes, tyres etc and make it more capable, too many focus on power anyway these days and don‘t maximise the car and get other things in line first. To gain speed and pace on a track and so on loose weight (the xarni mean) and upgrade brakes and chassis components, you‘ll get more noticeable gains this way.

Regarding the PBC/RBC thing, PBC I‘m not sure if it can just be bolted on, poss not but RBC is not worth the money, the gains from an RBC and throttle body are
Minimal vs the costs mate.

If the PBC can just go on you may benefit a bit but not sure how much mate

 

[nails]

I don't think he is planning on taking this car on track, it sounds like it is his daily car and he just wants it to sound better........correct me if I am wrong Cobblepop

 

[Cobblepop]

I don't think he is planning on taking this car on track, it sounds like it is his daily car and he just wants it to sound better........correct me if I am wrong Cobblepop

That's correct, I don't really have the money to turn it into a track beast so for now I'm simply looking at improving the sound. It would've been nice to squeeze a little more power out of it knowing I was having an exhaust made, that's why I enquired whether it was worth going for the full system with sports cat over the cat back only.

...on that point, I'm still not sure whether there's much difference between the two options, both in regard to power and sound...