VF SSV 6.0 Redline Commodore AUTO Sedan - exhaust recommendations

[JumboJim]

Thanks for the contribution Geoff. good to hear you had a noticeable improvement with just the HSV exhaust alone, and the OTR. Sounds encouraging for me!
Looking at the design of the HSV headers, they seem completely different in concept to the HOLDEN ones eh..
I have learned a lot looking up stuff on the net, mostly from the justcommdore forums. And this thread has helped me further - thanks a heap guys..
Bout the cats tho??

 

[ThunderLizard]

Hi JumboJim,

I wouldn't bother with just doing the Cats. If you were really serious, then go for both headers and cats. But i think you'll notice a big enough difference with the HSV header and cats plus OTR that you'll be happy to leave it there. It will be heaps better to drive anyway. I wouldn't stress about it. I think you'll be pleasantly surprised. Sure you could get a better sound/note, but where to you stop $$ wise? Let us know how you get on. Cheers TL

 

[JumboJim]

Well, the HSV header + cats + OTR plus custom tune is due to happen Monday and I'll share the before and after dyno stats...

I have some more questions if anyone has time to respond:
1. If I am offered a mafless tune, should I consider? I assume no as I have declared I am not chasing peak performance anyway.
2. If I decide I still want to change the note after this work, I'm now thinking I might leave the HSV header and cats and just change the cat back to Di Filippo, KPM or Manta. These seem to have the best reviews. Question: If I did this later, would it have much affect on the custom tune? I.e. Would I be likely to lose some benefit/performance, I'm guessing it wouldn't make massive difference, but preparing to be shot down?

 

[ThunderLizard]

Hey Jimbo,

I don't think they'll offer you the mafless tune, not for that upgrade anyway. I think from what i've read on here somewhere, that the mafless tune is only a benefit with forced induction or a cam package, but i'm certainly not an expert on this. As for the sound, i think you'll get the best results if you go with a complete system (headers, cats, catback etc) from one manufacture, i.e. complete manta, or Di Fillipo or whatever, as they've been designed specifically. Each will have it's own unique sound though. So if you're not happy with this result, my suggestion would be try and find systems that you can listen to in person. I think that will be the only way you'll be sure that what you get will be what you want. Unfortunately, sound/note is all subjective. What I like might not be what you like, so no one can really tell you for certain. But we can suggest ones that you should listen too. I'm keen to hear the result. Hope its exactly what you're after.

 

[panhead]

Hey Jimbo,

I don't think they'll offer you the mafless tune, not for that upgrade anyway. I think from what i've read on here somewhere, that the mafless tune is only a benefit with forced induction or a cam package, but i'm certainly not an expert on this. As for the sound, i think you'll get the best results if you go with a complete system (headers, cats, catback etc) from one manufacture, i.e. complete manta, or Di Fillipo or whatever, as they've been designed specifically. Each will have it's own unique sound though. So if you're not happy with this result, my suggestion would be try and find systems that you can listen to in person. I think that will be the only way you'll be sure that what you get will be what you want. Unfortunately, sound/note is all subjective. What I like might not be what you like, so no one can really tell you for certain. But we can suggest ones that you should listen too. I'm keen to hear the result. Hope its exactly what you're after.

MAFLESS tunes are done on headers, cats, exhaust and OTR with good improvements without a cam swap out or forced induction added.

I always go MAFLESS even with minor mods.


.

 

[JumboJim]

Thanks again for the contributions it's interesting to hear others views..

 

[JumboJim]

And, the results are in. I have only had a quick drive so far but my initial thoughts are:
1. It's a much better exhaust note now, I'm assuming it's the HSV headers to thank for it. It's a much more beatty, grumbly, growling noise.
2. Less drone now I reckon, as it's pulsing more.
3. Feels a big difference in power. Much more responsive as soon as the accelerator is touched, and feels more power throughout.
4. Can't say I have noticed much induction noise so far..
The Dyno results are below.. I think the standard, unmodified 6.0L is good for about 209kw? And I'm assuming the x force cat back (I already had) took this to the start benchmark of 223kw? The final result of 259kw looks like a more than 16% increase in power.

I know it's not going to set any records, but I feel like it's been a worthwhile upgrade.

Opinions welcome

Dyno

• JumboJim
• Dec 5, 2016

IMG_8330

• JumboJim
• Dec 3, 2016

 

[Not_An_Abba_Fan]

In the 30+ years I have been driving and tuning cars I can tell you that you can tune an engine up the wazoo but unless you have the characteristics built into the headers, secondary collector (in some cases expansion) and sound pulse management then you may as well not tune the engine at all.

Selling on flow versus sonic reflection is exactly where we disagree. OP wants a specific benefit that doesn't really factor flow / restriction, rather something proven that is good value, fits, sounds better and makes torque where full-on peak flow race headers won't at typical street RPM. The HSV mid throw fits the bill without hassle, doesn't matter really!

NAAF consider that gas particle restriction (and dynamics of pipe flow) is inherent, matched and velocity and acceleration a given. I would argue the more important principle at play for pressure drop at the valve is sonic reflection, for which these cheap little high rpm underdogs work a treat at 270°, excellent start with properly sized secondaries and HFCs.
As a step to the overall tune upgrade they compare favourably to any aftermarket headers aimed at low to upper mid range, typical street. No DTC / MIL drive away without retune With Euro 4 contraption else I swear by HSV mids + 2" mandrel + fat HFC barrel to bolt-up stock location, cancel rear O2 heater, else go for broke and run them up to 300wkw tune. They are strong overall.
The challenge is the restriction of the stock catback flange location to get the header and secondary / collector closer to ideal, in which case with a bit of customisation there are better front end combos but also cost a lot more money.

All well and good in an application where the revs are consistent. And how ever you "tune" your exhaust, it will be different hot and cold. Hot gas in hot pipes flows faster and with more volume than cold gas in cold pipes. Play with Pipemax all you like, but in the real world there are so many factors that affect exhaust performance. Fit 10 different systems and apart from sound, I would put money on the fact that your average Joe would be hard pressed to tell the difference on the street.

Then add cats in the mix. Cats are the most detrimental thing in the whole system. Whatever you fit in front of the cats will only flow well until the gas hits the cats. Then all the flow characteristics you have applied to the gas gets interrupted when the gas hits the cats.

Your second paragraph states almost what I was saying anyway. Keep the customer happy and fit something that sounds good.

 

[monstar]

And, the results are in. I have only had a quick drive so far but my initial thoughts are:
1. It's a much better exhaust note now, I'm assuming it's the HSV headers to thank for it. It's a much more beatty, grumbly, growling noise.
2. Less drone now I reckon, as it's pulsing more.
3. Feels a big difference in power. Much more responsive as soon as the accelerator is touched, and feels more power throughout.
4. Can't say I have noticed much induction noise so far..
The Dyno results are below.. I think the standard, unmodified 6.0L is good for about 209kw? And I'm assuming the x force cat back (I already had) took this to the start benchmark of 223kw? The final result of 259kw looks like a more than 16% increase in power.

I know it's not going to set any records, but I feel like it's been a worthwhile upgrade.

Opinions welcome

Jim I assume this is with the high flow cats, excellent and honest results, your comments spot-on. That tune has some margin if you really want to push it, with exact same setup I was same then 269 kW on flex fuel.
Your difference is enough to pip all stock HSV except the VFII and VF GTS, did you get a torque graph or chart showing RPM?
That's the only issue I have with Dyno Dynamics in Shootout 8.

 

[JumboJim]

Jim I assume this is with the high flow cats, excellent and honest results, your comments spot-on. That tune has some margin if you really want to push it, with exact same setup I was same then 269 kW on flex fuel.
Your difference is enough to pip all stock HSV except the VFII and VF GTS, did you get a torque graph or chart showing RPM?
That's the only issue I have with Dyno Dynamics in Shootout 8.

Thanks for the contribution Monstar. Actually, no this is with standard HSV headers, and HSV cats. From what I read, it's best when doing this upgrade to use the HSV cats because the HSV headers finish in a different position to the SS header, which means the SS cats won't align with the cat back... I don't know if there is any throughput difference between SS and HSV cats? I'm assuming no..

Unfortunately, I only have the graph I displayed above.

Great to hear how it compares to a stock HSV. very encouraging.

When you say that the tune has some margin, do you mean that if I were to bolt on replacement parts I would continue to get performance improvements? I was wondering if I were to change the cat back later, would I need to get a re-tune...?

Having driven the car last night and again this morning after my previous post. I can happily stand by my initial thoughts. This upgrade has made a very, VERY, V-E-R-Y big difference to the car.. It now sounds, well, like a HSV... It's not a hoonish loud noise, but a refined, good quality sound. The drone that existed with just the xforce cat back has gone. It is definitely the pulsing that has changed what was a monotone, sometimes tiresome note, into a much more pleasant sound. And when you boot it, it's a really nice roar.

I also noticed that before this upgrade, most of the noise came noticeably from the rear of the car. And, again, I feel like the plastic boot liner amplifies and adds a negative drumminess to the exhaust. Now, the sound feels much more balanced and travels under the car from the engine back. A much better and more involving feel to it...

No doubt after market headers and cats (and a better quality cat back) would lift the performance and sound further, but I am really quite happy with this result.. I'm certain already I won't change the headers as I like the idea that it's factory (HSV).. There is a good chance I'll change the cat back though, to either Difilippo, KPM, or Manta but only in stainless steel. I do like seeing the stainless systems from the rear...