Single or dual

[Guest]

Hi all, 

 

I've searched the forums but for the most part responses to this question have been based on aesthetics, and the argument ends up in accusations of  being a gay chav or a sheep  Whilst looks are a consideration, I would like to remove that from the argument. 

 

Taking that out of the picture, which is best for an NA HR? I have no intention of going FI in the future, and whilst most people seem to think that the duals are better, and it certainly seems the focus of the manufacturers, I see people racing higher HP NA zeds with single exhausts. Whilst I don't intend on racing (well, maybe track days when I'm not a complete novice), if I do pursue any power it will be the NA route. 

 

Can anybody confirm pros and cons to assist in decision? Is there a difference in power at all post tune? 

 

My exhaust is rusted to fook, and although I had hoped to focus on handling first, the mot man might say different 

[Ekona]

Best? Lightest and least restrictive, so arguably a true dual would be best. 

 

However, you’re talking fractions and tbh I’d just get the one you like the look and sound of. By all means spend £2k on a titanium job if you can afford it, but otherwise there’s not a lot in it really. 

[Jetpilot]

1 hour ago, Doom said:

Is there a difference in power at all post tune? 

No, your choice is purely down to budget and sound, but if you plan to do trackdays, make sure you dont go down the noisey  route, which a single exit will definitely be. which also rules out decats.

 

Personally i like the sound of a true dual.

Edited March 19, 2018 by Jetpilot

[Guest]

29 minutes ago, Ekona said:

Best? Lightest and least restrictive, so arguably a true dual would be best. 

 

Would lightest not be a single? There is less metal. 

 

I'm trying to understand the restriction thing as a lot of people talk about it, but I see 400ish hp n/a cars racing with a single 3.5" pipe, so is restriction much of an issue when not FI? 

 

21 minutes ago, Jetpilot said:

if you plan to do trackdays, make sure you dont go down the noisey  route, which a single exit will definitely be. which also rules out decats.

 

I assume that noise regulations are relatively tight for track days in the UK?

 

Would a dual with resonated de-cat pipes likely be ok or do you think limits will be breached?

 

Do the same noise restrictions not apply for actual motorsport races? 

[Jetpilot]

Silenced/resonated decats make little to no difference on actual noise, they just take away some of the rasp and drone. All depends what track days you are doing but if you aim for circa 98-100db static that will get you on most days, but a single or dual with decats and you will be pushing it.

[Ekona]

With track day limits in mind, aim for as quiet as possible. You’d be better off running two setups, one for the track (OEM) and one for the road (whatever you like). Best of both worlds that way. 

[Guest]

35 minutes ago, Ekona said:

With track day limits in mind, aim for as quiet as possible. You’d be better off running two setups, one for the track (OEM) and one for the road (whatever you like). Best of both worlds that way

2 exhaust setups? Don't think I have the space (or a wallet fat enough) 

[StevoD]

3 hours ago, Ekona said:

Best? Lightest and least restrictive, so arguably a true dual would be best. 

 

However, you’re talking fractions and tbh I’d just get the one you like the look and sound of. By all means spend £2k on a titanium job if you can afford it, but otherwise there’s not a lot in it really. 

how is a true dual lighter than a single?

[EzeePzee]

A true dual exhaust on a TT 350z paired with motordyne ART pipes sounds great and looks good too. 

[Ekona]

9 minutes ago, StevoD said:

how is a true dual lighter than a single?

Well it’s not, but it’s less restrictive and my OCD prefers one either side  

[Guest]

But if restriction is a problem, why do people like Michael Gardner or Sasha Anis run with single pipes on highly modified and tuned n/a vehicles? iirc the on point 350z is around 420 whp. 

 

Not that I have aspirations to that unless someone wants to triple my salary, it just seems to run contrary to most claims of better flow being important, and I wanted to understand so that I can make the best selection for myself, although it sounds as though if I want to ever really try it on a track I will need a dual setup, or 2 exhausts as per your suggestion. 

[Ekona]

Honestly, unless you're planning on serious head work, cams etc then it doesn't make any difference. Anything other than stock will see an improvement, it just matters on what you want it to look like and how deep your pockets are.

[andybp]

Seriously if you're staying N/A then go with what looks and sounds good

[Guest]

But, but, but, my ocd needs sating  Provided examples run contrary to generally accepted wisdom and my curiosity is piqued!

 

I wouldn't want to rule out cams in future tbh, when I do opt to pursue power it will be the n/a route. 

[andybp]

2 minutes ago, Doom said:

But, but, but, my ocd needs sating  Provided examples run contrary to generally accepted wisdom and my curiosity is piqued!

 

I wouldn't want to rule out cams in future tbh, when I do opt to pursue power it will be the n/a route. 

quite a few of us with ocd issues here 

it's your hard earned spend it how you will but without spending a lot N/A the exhaust won't make you much power no matter what

[Guest]

24 minutes ago, andybp said:

quite a few of us with ocd issues here 

it's your hard earned spend it how you will but without spending a lot N/A the exhaust won't make you much power no matter what

The question now isn't really whether it will provide any power benefits, I know those are minimal without other serious modifications, so essentially theoretically it doesn't matter what I choose, as long as I like it, and it doesn't preclude me from track opportunities by sounding like a spitfire. 

 

However, most claim that true duals are better and the claim makes sense, more airflow, more potential power assuming +mods. But some of the people I've seen online with very tuned zeds that they race are running with single pipes. If this were disadvantageous then they wouldn't be using those at close to or in excess of 400hp. Given how much they have spent on cams, headers, throttle bodies, tuning, etc, switching to a dual would be nothing by comparison were it likely to provide additional gains. If they haven't switched, they have decided that either it won't provide +power, or the +power is offset by some disadvantage. So is a true dual system actually advantageous for an n/a application, or do the benefits of 2 pipes over one only really make themselves noticed for FI? Trying to understand this discrepancy so that the logic clicks in my head. If I need to go read something, pointers / recommendations from anybody are gladly received 

 

As an indication of my compulsion to understand things, here is my bedtime reading 

 

[StevoD]

4 hours ago, Ekona said:

Well it’s not, but it’s less restrictive and my OCD prefers one either side  

is it tho MY single is a close as damn it a straight line a tue dual doesnt have the same pleasure.

 

and it does seem odd all the time attack boys in the USA seem to run a single not a true dual. 

 

not saying it made the power wise but i recall when mouthwash got his car retuned with the Agency power after the supercharger it made a reasonable WHP increase 

[Foo56]

Seems as though no real clarity on this - I’m going to be pulling the trigger on a custom exhaust soon and was asking the same question!

 

in my mind, as long as it’s as close to a straight line as it can be then single would be lighter provided manufactured well enough to ensure Its not restrictive on airflow... True dual looks cooler but twice(?) the weight?

 

for me weight is important and I’m trying to keep that down so may just go single for now but if there are gains to true dual (even if only small)  I’ll more likely lean on that side if the fence.

[Jetpilot]

On 19/03/2018 at 21:38, Doom said:

The question now isn't really whether it will provide any power benefits, I know those are minimal without other serious modifications, so essentially theoretically it doesn't matter what I choose, as long as I like it, and it doesn't preclude me from track opportunities by sounding like a spitfire. 

 

However, most claim that true duals are better and the claim makes sense, more airflow, more potential power assuming +mods. But some of the people I've seen online with very tuned zeds that they race are running with single pipes. If this were disadvantageous then they wouldn't be using those at close to or in excess of 400hp. Given how much they have spent on cams, headers, throttle bodies, tuning, etc, switching to a dual would be nothing by comparison were it likely to provide additional gains. If they haven't switched, they have decided that either it won't provide +power, or the +power is offset by some disadvantage. So is a true dual system actually advantageous for an n/a application, or do the benefits of 2 pipes over one only really make themselves noticed for FI? Trying to understand this discrepancy so that the logic clicks in my head. If I need to go read something, pointers / recommendations from anybody are gladly received 

 

As an indication of my compulsion to understand things, here is my bedtime reading 

 

 

To answer your question simply, lets say you are 400hp and running a 3" single exit, you wont get anymore hp by running a 4" single exit, you are already flowing enough air on 3" for say the 400hp, as you go up in power of course, you may need to up the diameter to cope with the air flow needed for say 500hp.

 

Same goes for running a dual and this is where it gets funky, you would think to match a single 3" you would need two 1.5" dual, but that is not the case, you need to work with pye r squared to work out volume. A few gentle bends here and there make little difference, so a decent dual wont affect flow rates or if the same diameter pipe as a single it wont increase the hp as you already making the most of the breathing your engine can supply. I would imagine as above most guys running single are doing so for the weight saving.

 

To be fair, when i was booking my fi'd zed to be mapped with hdev i asked what of my two exhausts would give better figures, single fujitsubo or dual hks, the answer was it really wont make any or little difference.

 

I truly doubt you will get on any track day with a single.

 

https://www.hotrod.com/articles/what-exhaust-pipes-work-best/

 

 

Edited July 20, 2018 by Jetpilot

[StevoD]

I've had track days on a single as did GrunDy when he was with us 

[Jetpilot]