VF Exhaust Sound

[NewbC4KE]

Well, yes. Why is that a surprise when you look at what is being sold under the guise of Performance Exhaust?
Most are overpriced marketing fluff, plus the "gains" are fabricated via the tuning.
Would surprise most buyers to know what it takes for an effective exhaust near stock tune.
Certainly ain't 1 7/8" headers, no merge, no secondary, cats in the original location, etc.

Just to be clear as tone is not understood when ready from a screen, I was not being a smart arse I am not mechanically minded and freely admit that I am just trying to learn/understand and when I read your posts most of the time I find I have to do a lot of reading between the lines.

"Would surprise most buyers to know what it takes for an effective exhaust near stock tune." what does this mean?

The OP is going to get his car tuned and the dimetime car has been tuned?

 

[monstar]

Well, yes. Why is that a surprise when you look at what is being sold under the guise of Performance Exhaust?
Most are overpriced marketing fluff, plus the "gains" are fabricated via the tuning.
Would surprise most buyers to know what it takes for an effective exhaust near stock tune.
Certainly ain't 1 7/8" headers, no merge, no secondary, cats in the original location, etc.

Just to be clear as tone is not understood when ready from a screen, I was not being a smart arse I am not mechanically minded and freely admit that I am just trying to learn/understand and when I read your posts most of the time I find I have to do a lot of reading between the lines.

"Would surprise most buyers to know what it takes for an effective exhaust near stock tune." what does this mean?

The OP is going to get his car tuned and the dimetime car has been tuned?

In terms of overall tune - volumetric efficiency, thermal and fuel efficiency, torque and peak HP RPM - there are varying states from stock to wild.
Near stock for example (as in 245rwkw / 530 Nm on a Mainline or DynoDynamics in Shoot8), doesn't require 1 3/4" headers or an OTR.
Similarly 300rwkw doesn't require more than 1 3/4" 4-2-1 HSVs.
If you are good to read a dyno then it pays to invest in some real research.

 

[Not_An_Abba_Fan]

I agree with PIR4TE, 4-1's with no collector length are pointless. As soon as the diameter of the pipe changes after the merge, that is where the "collector" ends so having the cat right at the merge is not good for torque. Whatever you are gaining in primary sizing (both length and diameter), you lose in velocity in the absence of the collector. It's not optimal, but it will be better than the stock manifolds. You will see an increase in performance but it's a flawed set up.

RWKW on a dyno is not the be all and end all either, the dyno is a tuning tool. Look at where the torque curve starts and how sharply it rises and how long it goes for before it drops off. Every header design will produce a different curve, as will the tunes. Header design is not just about peak power.

 

[PeteSS]

Ok, need to make a choice. Can get Hurricane headers/high flow cats ($1600) from Not an Abba Fan, and then OTR and Tune ($1200-1400) from somewhere, total $2800-3000 vs Pacemaker headers/highflow cats/OTR/Tune from 1 place for $3680. So premium of $600-800 for teh pacemaker brand. Is it w
Ok, need to make a choice. Can get Hurricane headers/high flow cats ($1600) from Not an Abba Fan, and then OTR and Tune ($1200-1400) from somewhere, total $2800-3000 vs Pacemaker headers/highflow cats/OTR/Tune from 1 place for $3680. So premium of $600-800 for teh pacemaker brand. Is it worth the premium for the Pacemakers?

Mine stated off with Pacemaker 1 7/8 headers with hi flow cats, with a 3 inch stainless Pacemaker cat back. Sounded awesome, but way too loud for a daily driver. The centre section was literally straight through pipes. no centre mufflers

It now has the same headers and cats, but with a 2.5 inch Hurricane system with x pipe centre mufflers, and single exit mufflers as opposed to dual. Still as loud at idle (due to the cam) but noticeably quieter through the rev range, to the point of now wishing it was a bit louder. The Hurricane does sound nicer though, as the Pacemaker was very boomy

. The point is you could spend a fortune on exhaust and still not get what you're after

 

[NewbC4KE]

With the images above have I identified the collector correctly?

Manta setup has a slightly longer Collector than Dimetimes setup which in Theory/fact is better?

So the DPE has a much longer collector maybe to long?

 

[monstar]

With the images above have I identified the collector correctly?

Call the merge point (of gas particle acceleration) what you will of course, and it does have several common names, but that device does not serve the same purpose as a collector, no. A collector is the secondary pipe after the merge. Before the cat. It can be seen in the DPE shot.

 

[ProjectHeron]

Monstar/Notanabbafan - what are your views on what route to take with exhaust for a 6.2LS3 already with stock HSV 340 headers and cats.
Is there benefit in header/cat upgrade, cat back, mufflers only, or dont bother with any of it?

Chasing improved street performance and slightly better sound (not that its bad at the moment)

Keen on your views given your very obvious detailed exhaust knowledge rather than marketing and self promotion you tend to get from the tuners as of course everyone is better than the competition right..!

 

[monstar]

Monstar/Notanabbafan - what are your views on what route to take with exhaust for a 6.2LS3 already with stock HSV 340 headers and cats.
Is there benefit in header/cat upgrade, cat back, mufflers only, or dont bother with any of it?

Chasing improved street performance and slightly better sound (not that its bad at the moment)

Keen on your views given your very obvious detailed exhaust knowledge rather than marketing and self promotion you tend to get from the tuners as of course everyone is better than the competition right..!

Yes mate there are better things than the SV340 headers but... as an all-rounder they are hard to beat, and nothing is gonna get you closer to the ADR / EPA gods, ever.
Cat back issue is seperate to headers.
Headers are always a compromise but err on the side of early, high long torque curve (PH5387) vs late peaky HP numbers as mentioned above.
So that means not too big dia primaries and decent long throw. Longer collector with x-pipe is ideal for our two tonne Tess. Personally I'd sacrifice some HP over 6000 rpm and have it as streetable torque around 4000 (4-2-1). But that depends if you are seeking dyno figures / 0-400 or street performance.

 

[Not_An_Abba_Fan]

The collector is the length of the pipe after the merge before the first diameter change, IE the cat. The length of the pipe before the flange is irrelevant, the effective collector extends after the flange to the cat. In the Manta system you can see that the cats are further back than the HM ones, the DPE cats pretty much bolt directly to the headers. So from a performance perspective, the DPE and Manta setups are better than HM.

As PIR4TE says, there are better options. Entirely depends on what you're after. IMO, long tube 4-1's also sound better than 4-2-1's. A decent cat back will keep the exhaust moving along nicely. X pipe? Tomato tomarto, personally I don't like them as they are put together wrong in 99% of the cases and too close to the engine. It becomes a restriction at high revs, but if all you do is putt around town with the occasional blat, it's adequate. Also they "muddle" the note as well. I like the H pipe set up as it has a more distinguished V8 pulse.

Performance wise, 4-2-1's with an X pipe produces great acceleration but you do lose some top end. 4-1's with a H pipe will have more top end but the loss down low is negligible. Only really noticeable on a dyno. Side by side with the same mods, there would be bugger all difference on the 1/4 even.

Having been involved with a few street drag cars, I've seen multiple set ups win and lose. Changing driving style and tyre pressures have more effect than exhaust set up on a street car.

Go big then tune it correctly. The exhaust is only there to meet legal requirements.

 

[TheHulkcar]

I agree with PIR4TE, 4-1's with no collector length are pointless. As soon as the diameter of the pipe changes after the merge, that is where the "collector" ends so having the cat right at the merge is not good for torque. Whatever you are gaining in primary sizing (both length and diameter), you lose in velocity in the absence of the collector. It's not optimal, but it will be better than the stock manifolds. You will see an increase in performance but it's a flawed set up.

RWKW on a dyno is not the be all and end all either, the dyno is a tuning tool. Look at where the torque curve starts and how sharply it rises and how long it goes for before it drops off. Every header design will produce a different curve, as will the tunes. Header design is not just about peak power.

Hi NAAF and Monstar, so Ive been reading through a heap of posts regarding exhaust setups (it's so confusing with so many opinions to the layman - me) however Im learning A LOT! Ive got a VF2 Redline and researching for a full exhaust upgrade. So in your humble opinion what are these like from Sureflo with the Ballistic cat? To me it looks there is no collector length before the cat, is that right and therefore no good? I think they also use an x-pipe in their setup cat-back...
Im also looking at the full DiFillippo as it seems to be highly recommended on here with the longer collector and h-pipe. I'd just prefer get the entire setup from one place rather than buying various pieces of the exhaust, trying to mate them together and then have some place fit it all together...

http://www.surefloexhaust.com.au/holden/commodores/ve.htm