Extractors with stock exhaust?

[Troy711]

I'm thinking of whacking a set of Pacemakers on the Stato. Would I see much improvement if I retain the stock exhaust? Only reason I would keep the exhaust standard is because I don't want it hecticly loud.

[Ado]

Just get the exhaust to flow good with minimal extra sound,it can be done.The Statesman has non stock exhaust with high flow cats and is not too loud.Its built for more power not more noise.Any GOOD exhaust place will be able to help you out.

[Troy711]

Actually.. I heard this:

YouTube - Holden Commodore SV6 2.5 inch Exhaust

And it sounds pretty good (for a 6).

[Surfwagon]

If you don't want it loud but want a decent flow why not buy a second hand HSV cat back.
They are on eBay all the time, $100-250, definately worth the money and they are full stainless steel.
You'll just need to adjust the length if you buy a normal sedan system.
I have seen grange systems on there before.
A lot of super6 guys do this, nice note and still get decent hp figures.

[Not_An_Abba_Fan]

Putting extractors on and keeping the stock system will give you better economy and better low to mid torque. But use Tri Y's. If you put tuned length on, all you will do is create more back pressure as the extractors will get the exhaust moving faster but the stock system will choke it back.

[Troy711]

Holden VE V6 Commodore Pacemaker Headers / Extractors - eBay Extractors, Exhausts, Car Parts, Accessories, Cars, Bikes, Boats. (end time 25-Jun-09 19:04:58 AEST)

This is what I was looking at

NAAF: Wanna do me a deal on a set

[Not_An_Abba_Fan]

That set is bloody cheap....but I can do you a one off for $400 even....normally $420. Postage, according to the Auspost calculator would be approx $40, or if you are going to Sydney you could pick them up.....

[Troy711]

Would a cat-back set up do much? Or would it just be for a louder note?

[Not_An_Abba_Fan]

It would make a small difference, but the cost wouldn't justify it. There isn't much available for the WM V6, on the V8 it would make more of a difference. I would leave it unless you wanted to spend another grand for not much improvement.

[Troy711]

I should just save my pennies for a decent S/C kit. I've just gotta work out how to write it off on tax lol

[Not_An_Abba_Fan]

Change the invoice from "supercharger" to "Office Supplies"......

[Troy711]

I could get the worked booked out to my Hiace... it's going in to get lowered on Friday hahaha (actually no, the Statesman is but the invoice says it's for the Hiace)

[love the general]

get the invoice made out for an air compressor. technically its right lol

[vsv6dude]

Putting extractors on and keeping the stock system will give you better economy and better low to mid torque. But use Tri Y's. If you put tuned length on, all you will do is create more back pressure as the extractors will get the exhaust moving faster but the stock system will choke it back.

Hi Abba

Will the extractors with the stock exhaust improve fuel economy for city driving or is it country driving you were referring to or to both?

[Not_An_Abba_Fan]

Bit of a thread dig.

The economy will be better in both city and country driving, more noticebly country though. But it is also directly related to your right foot. The car will be more responsive so you may be tempted to put your boot into it more.

[vsv6dude]

In respect to low end torque I guess this also improves requiring less throttle use to achieve the same performance compared to the stock headers

[Not_An_Abba_Fan]

Yes, but because more spent gases are removed from the combustion chamber allowing more fresh air in.

[Crisis63]

Bit of a thread dig.

The economy will be better in both city and country driving, more noticebly country though. But it is also directly related to your right foot. The car will be more responsive so you may be tempted to put your boot into it more.

That there, and the sound, is the trap. ;-)

[vsv6dude]

Hi Abba

Just to clear up my understanding will both tuned length extractors and the interference extractors when used with a standard exhaust have the same affect on fuel economy and low end torque. Or is it just the interference extractors ?

Either way if that is the case why it is that exhaust specialists don't tell this fact and make it common knowledge when customers enquire about them?

It seems that most exhaust joints promote the catback sports system which is more for top end rather than promoting extractors and keeping the catback system stock for bottom end performance. I guess its each to there own.

As I drive around town I like the extra low end torque and improved fuel economy aspects and for that reason it would be my first upgrade when a new vehicle is out of warranty.

To clarify for city driving with the interference extractors is the fuel saving achieved whilst accelerating (including from stand still) and the fuel saving achieved whilst cruising in the city or from both ?

The extractors I have in mind to install are the HM99SS in my VS V6.

The answers to these queries should become a sticky to take the mystery out of exhaust science IMO.

[vsv6dude]

Hi Abba

To clarify for city driving with the interference extractors is the fuel saving achieved whilst accelerating (including from stand still) and the fuel saving achieved whilst cruising in the city or from both ?

The extractors I have in mind to install are the HM99SS in my VS V6.

The answers to these queries should become a sticky to take the mystery out of exhaust science IMO.

[Not_An_Abba_Fan]

For what you will pay for the HM's, it won't be worth the effort. You will save on fuel but you won't see any return for a very long time because the HM's are an expensive exercise in cost to saving ratio.

Shops promote cat backs because they are quick and easy to fit and can fit 5 or 6 cat backs in the time it takes to fit extractors and thus make a shit load more money.

You would save more fuel cruising than accelerating, but as long as you accelerated at the same rate as you would with standard manifolds, you will still save fuel.

[vsv6dude]

Abba

I can get the HM's at trade plus a good price to fit.

Is the HM header design better suited for low end than the pacemakers.

In response to scavenging as spent gases are removed more efficiently more oxygen can then be pumped in to the cylinders.

If more oxygen is available is slightly more fuel is required to maintain the fuel/air ratio as monitored by the oxygen sensors or does the ECU just inject the same amount of fuel and as more oxygen is available (spent gas is removed by the extractors) the combustion process is more complete hence better performance. As there is better performance you can back off on the accelerator.

[vsv6dude]

Hi Abba

I have noted that high ratio rocker resellers do not promote extractors they claim that you will lose bottom end kind of the opposite of what has been discussed here. They claim it should be the last mod that should be done.

I guess if the tuned extractors are used the low end torque loss due to high ratio rockers will be even greater. Is this why they fear them ?

[Not_An_Abba_Fan]

The reason high ratio rockers increase bottom end is because they throw more air/fuel mix in, this gives a bigger bang thus producing more bottom end acceleration. Extractors speed up the exhaust flow and scavenge the combustion gases so more clean air can get in. Extractors increase bottom end as well, but fitting high ratio rockers is the easy way to get a larger profile cam effect, but they don't change duration, only lift so the pressure waves in the intake runners and the exhaust ports are all wrong. Sure they give a bit more go, but are not the ideal way to increase performance effectively.

What happens when fitting extractors is the torque curve is moved higher in the revs as a more effective intake charge is delivered at higher revs with less back pressure in the exhaust. It's not that you lose bottom end, just the torque curve starts a bit later and goes for longer making it FEEL like you have lost bottom end. The best balance is to fit a manifold spacer as well as extractors, lengthening the intake runners and moving the torque curve lower again.

[vsv6dude]

Abba to close out this thread.

In summary fitting extractors either Pacemakers, HM Headers, Advance Headers and others to the stock Ecotec V6 3800 with a stock exhaust, the following is true.

1. Better Fuel economy providing the right foot exerts same pressure or less on the accelerator compared to stock header
2. Better acceleration compared to the stock header
3. Better low end torque compared to the stock header
4. Top end gain compared to the stock header (corrected based on advice from Not_An_Abba_Fan)

It is assumed that the vehicle is regularly maintained, in good condition and quality fuel / parts are used.