Extractors and torque one last time

[vsv6dude]

For member with basically a stock V6 ecotec engine.

With stock boost of 6psi the factory exhaust actually does an ok job of getting the gases out. We usually find on a stock engine an exhaust upgrade usually only delivers 7-8kW gain and loss of torque down low.

Don't Upgrade your headers until one of the very last modifications on your Power Plan agenda. Applying high flowing Extractors too early in the modification process will lead to massive loss of Torque and Response down low.

"If you do the Exhaust and Extractors first and had run out of money to do the Boost and Rocker components, you end up being disappointed with the performance due to lack of response and Torque down low and wishing you had of done the Boost and Rockers instead. Our Power Plan Modification in Order of Priority:

10psi Boost Upgrade
1.9:1 High Ratio Rockers
Type-S Cold Air Intake
Cat Back Exhaust
Then Extractors
It has taken us 7 years of Development to Perfect this formula. It works flawlessly everytime and we know you will be happy ever step of the way with your upgrades."

The above extracts are from the questions of a certain performance website, however they promote some common myths I have found.

Loss of torque (or rather the shift of torque to the mid to high rev range) you will note is cause by 2 keys things from the above comments
1. Over sized exhaust not flowing sufficient volume of gases low down cooling
2. Over-sized hi flow extractors not flowing sufficient volume of gases low down.
In both 1 & 2 above the gases cooled increase in density requiring more energy to push the gases out until the high rev range is reached.

In discussion with NotanAbbaFan it has become clear if the extractors and free flowing exhaust are correctly sized for the application then there will be the opposite
1. Improvement to low end torque or shifting the torque curve low in the rev range
2. Less work by the engine in scavenging and propelling the engine.
3. Both the extractor type and size is just as much a culprit as larger sized exhaust system

It seems then that members before, making statements in certain situations, should examine the real cause of loss of torque and acceleration.
Perhaps a better performance plan compared to one above would be

• Cold Air Intake (POD encolsed or Super 6 OTR)
• Then Extractors (interference type and correctly sized 1.5" primaries and 2" secondaries)
• Stock exhaust

Should further improvements to torque be required.

stock size catback sports system
12mm manifold insulator

These mods are low risk and are ideal for street driven vehicles requiring performance improvement in 1000rpm to 4000rpm range.

Too many times I have read on this forum after I installed in my extractors I got my some of my low end torque back after high ratio rockers and oversized catback exhaust installation. What caused the torque curve to shift ? Is this why extractors are said to be done last. When if fact they should be done first.

[Not_An_Abba_Fan]

The reason the extractors would be the last upgrade accoring to them would be because the effect of their upgrades would not be as dramatic if extractors and an exhaust were already there.

It's got nothing to do with which mod gives what effect, it is all about perceived improvement. If you had extractors and other mods first, the boost upgrade wouldn't feel as impressive as it would when done first.

To answer the question "what caused the torque curve to shift", it is all about exhaust velocity and air/fuel delivery. The faster you can get the exhaust moving, the better the scavenging effect and the faster you can get clean air in, rather than trying to reburn some spent exhaust gas. It's not about how much exhaust gas you can move, but how fast you can move it with the least amount of restriction.

[vyseriesII]

Very informative. Cheers for putting that up

[TI3VOM]

For member with basically a stock V6 ecotec engine.
It has taken us 7 years of Development to Perfect this formula. It works flawlessly everytime and we know you will be happy ever step of the way with your upgrades."

Sounds like good info, but one thing I noticed is that it has taken you guys 7 years to perfect all that, but you have not realized that your actually talking about a L67 supercharged engine and not a stock L36 ecotec lol

A lot of people will benefit from this info

[vsv6dude]

Sounds like good info, but one thing I noticed is that it has taken you guys 7 years to perfect all that, but you have not realized that your actually talking about a L67 supercharged engine and not a stock L36 ecotec lol

A lot of people will benefit from this info

It was understood that quotes are from a supercharged site.

Same principles still apply regarding "quoting myths" and how mods are promoted to create perception.

Please don't misconstrue that bolt ons and advertising is a bad thing.

[vsv6dude]

The reason the extractors would be the last upgrade accoring to them would be because the effect of their upgrades would not be as dramatic if extractors and an exhaust were already there.

It's got nothing to do with which mod gives what effect, it is all about perceived improvement. If you had extractors and other mods first, the boost upgrade wouldn't feel as impressive as it would when done first.

To answer the question "what caused the torque curve to shift", it is all about exhaust velocity and air/fuel delivery. The faster you can get the exhaust moving, the better the scavenging effect and the faster you can get clean air in, rather than trying to reburn some spent exhaust gas. It's not about how much exhaust gas you can move, but how fast you can move it with the least amount of restriction.

Spot on. Do the mods in the order that creates the perception of the greatest gain for each.

Called performance mods and performance marketing ?

At the end of the day they will all achieve the same result regardless of the order that they are all installed in, once they are all installed.

But isn't there a limit that can be obtained from any engine.
There surely cannot be compounded gain.

I guess a point will be reached where with each additional "bolt on", the improvement becomes very marginal, as the engine capability is fully exploited.

Please don't misconstrue that bolt ons and advertising is a bad thing.

[Not_An_Abba_Fan]

I'm just talking about exhaust modification here, not all bolt on mods. The only reason an exhaust system is fitted to a car is to comply with legal restrictions. IE: noise levels and emissions. The exhaust system is ALWAYS restrictive. Too small and it won't flow, too large and it flows well initially, but then as the exhaust cools, it loses velocity and creates back pressure - a restriction.

The best exhaust is straight out of well designed TUNED length headers. No pipework after that and definitely no mufflers.

The best solution for an exhaust as far as flow goes is to start larger, then reducing the pipe diameter the further away from the headers you get. The hotter you can keep the exhaust pipe, the faster it will flow without turbulance. Hence why a lot of Japanese manufactured vehicles have insulated exhausts.

As you say, there is a limit to the engines capability with bolt on mods, but it is not so much increasing the engines performance, but rather releasing it's potential. Remembering that the exhaust system's primary function is to keep the vehicle quiet and to keep emissions low. To achieve this, it is restrictive. Remove the restriction and the engine responds favorably. Extractors do this by scavenging the exhaust gases from the combustion chamber increasing the available space to allow a greater fuel/air mix in creating a bigger bang. A bigger bang equals more power. Well, more torque.

[vsv6dude]

The reason the extractors would be the last upgrade .....................

To answer the question "what caused the torque curve to shift", it is all about exhaust velocity and air/fuel delivery. The faster you can get the exhaust moving, the better the scavenging effect and the faster you can get clean air in, rather than trying to reburn some spent exhaust gas. It's not about how much exhaust gas you can move, but how fast you can move it with the least amount of restriction.

It does have to do with volume because as the revs increase the volume of air mass is increased so the air mass has to speed up. Maybe we are saying the same thing. From physics pipe flow Velocity = Volume divided by the cross sectional area of the pipe. The extra volume is achieved higher up in the rev range.

[ari666]

lol. useful info? to be taken with a grain of salt.

learn about exhaust gas velocity/heat loss and the vacuum affect created by a well made set of extractors and the above post will make more sense.

clearly their exhaust systems are not designed to create low down torque, however most extractors are/do. what they are saying is if you fit their exhaust before you turbo itll be a waste of time.

so basically all that info is useless to anyone that isnt going to turbo their car= 98% of JC users

[Pub247]

Supercharged ....

[vsv6dude]

lol. useful info? to be taken with a grain of salt.

learn about exhaust gas velocity/heat loss and the vacuum affect created by a well made set of extractors and the above post will make more sense.

clearly their exhaust systems are not designed to create low down torque, however most extractors are/do. what they are saying is if you fit their exhaust before you turbo itll be a waste of time.

so basically all that info is useless to anyone that isnt going to turbo their car= 98% of JC users

You are right. Read the opening sentence.

"For member with basically a stock V6 ecotec engine." and likely to keep it that way.

Your comment about 98% turbo the vehicle on JC IMO is BS. More accurate total BS.

There are members that likely to do very basic mods for improved drive-ability. eg catback, CAI, maybe HRR rockers and have their vehicles as show ponies.

I sure there are members that find will it useful.

Like other threads it is likely to get buried over the next few months anyway.

[ari666]

Your comment about 98% turbo the vehicle on JC IMO is BS. More accurate total BS.

you probably should spend more time reading, friend.

[TI3VOM]

For member with basically a stock V6 ecotec engine.

With stock boost of 6psi the factory exhaust actually does an ok job of getting the gases out. We usually find on a stock engine an exhaust upgrade usually only delivers 7-8kW gain and loss of torque down low.

Don't Upgrade your headers until one of the very last modifications on your Power Plan agenda. Applying high flowing Extractors too early in the modification process will lead to massive loss of Torque and Response down low.

"If you do the Exhaust and Extractors first and had run out of money to do the Boost and Rocker components, you end up being disappointed with the performance due to lack of response and Torque down low and wishing you had of done the Boost and Rockers instead. Our Power Plan Modification in Order of Priority:

10psi Boost Upgrade
1.9:1 High Ratio Rockers
Type-S Cold Air Intake
Cat Back Exhaust
Then Extractors
It has taken us 7 years of Development to Perfect this formula. It works flawlessly everytime and we know you will be happy ever step of the way with your upgrades."

The above extracts are from the questions of a certain performance website, however they promote some common myths I have found.

Loss of torque (or rather the shift of torque to the mid to high rev range) you will note is cause by 2 keys things from the above comments
1. Over sized exhaust not flowing sufficient volume of gases low down cooling
2. Over-sized hi flow extractors not flowing sufficient volume of gases low down.
In both 1 & 2 above the gases cooled increase in density requiring more energy to push the gases out until the high rev range is reached.

In discussion with NotanAbbaFan it has become clear if the extractors and free flowing exhaust are correctly sized for the application then there will be the opposite
1. Improvement to low end torque or shifting the torque curve low in the rev range
2. Less work by the engine in scavenging and propelling the engine.
3. Both the extractor type and size is just as much a culprit as larger sized exhaust system

It seems then that members before, making statements in certain situations, should examine the real cause of loss of torque and acceleration.
Perhaps a better performance plan compared to one above would be

• Cold Air Intake (POD encolsed or Super 6 OTR)
• Then Extractors (interference type and correctly sized 1.5" primaries and 2" secondaries)
• Stock exhaust

Should further improvements to torque be required.

stock size catback sports system
12mm manifold insulator

These mods are low risk and are ideal for street driven vehicles requiring performance improvement in 1000rpm to 4000rpm range.

Too many times I have read on this forum after I installed in my extractors I got my some of my low end torque back after high ratio rockers and oversized catback exhaust installation. What caused the torque curve to shift ? Is this why extractors are said to be done last. When if fact they should be done first.

What's the point of this thread mate?

[vsv6dude]

What's the point of this thread mate?

Reread the post. For members with vehicles and basic mods looking for low end gains.

The main point point of the thread is likely outcomes when installing extractors and when installing a catback system.

Understanding the relationship between extractor size and catback systems pipe size and impacts on low end torque an top end power.

Influence of advertising regarding basic exhaust mods and perceived performance gains.

If you still don't get it then ignore this thread its not for you. Like the other 1001 threads plus that exist this forum it may not be for everyone.

[TI3VOM]

Every single modification has an effect on where the engines peak torque is made.
If you put the right parts onto an engine you can make an engine with an even spread of torque all across the rev range. If you have no idea as to what your doing and just slap and engine together without making sure everything works in sync with one and other, it's will have a loss or gain somewhere in the rev range!

[vsv6dude]

Every single modification has an effect on where the engines peak torque is made.
If you put the right parts onto an engine you can make an engine with an even spread of torque all across the rev range. If you have no idea as to what your doing and just slap and engine together without making sure everything works in sync with one and other, it's will have a loss or gain somewhere in the rev range!

You are right.

If I had known that catback system generally cause a loss of low end torque and extractors genrally increased the low end torque.

I would have put in the extractors before the catback system.

Thats what this thread about the truth in the way science works to achieve your goals.

[Not_An_Abba_Fan]

You are not really losing or gaining anything, but rather moving the torque curve. Any modifications made affect how much fuel is delivered and when, that is what is actually moving the torque curve, not the actual modification.

[vyseriesII]

While the op might not be an exact science. It has its merrit. Not sure why it has to be shot down in flames by some people. Everyones car is different at different levels of modification. People can take it or leave the info posted by the op.

[TI3VOM]

You are not really losing or gaining anything, but rather moving the torque curve. Any modifications made affect how much fuel is delivered and when, that is what is actually moving the torque curve, not the actual modification.

That's what I meant, as in you will lose say low down torque but it will be shifted up higher, so you will gain more in the higher revs and visa versa.

[ari666]

People can take it or leave the info posted by the op.

people are generally stupid and they need to know that the info posted on the internet isnt always correct.

[vsv6dude]

people are generally stupid and they need to know that the info posted on the internet isnt always correct.

I guess what you you are really saying is that forum members are generally stupid and need your wisdom is required to point that out.

Another one of your comments that is total BS similar to Post Number 11 above.

We prayed Lord have Mercy and the People said Amen.

[ari666]

are you upset that i am saying your facts are flawed, and that maybe you should read you copy/pasta posts, and have a greater understanding of what it is you are copying BEFORE actually posting it?

and just for the record:

so basically all that info is useless to anyone that isnt going to turbo their car= 98% of JC users

means 98% of JC users ARE NOT going to turbo their cars, which means the info is useless to all but 2%. again, a situation where you should spend a little more time digesting the info before you hit the reply button.

so then the lord saw the light, and it was good (or some other weird rant)

[vsv6dude]

are you upset that i am saying your facts are flawed, and that maybe you should read you copy/pasta posts, and have a greater understanding of what it is you are copying BEFORE actually posting it?

and just for the record:


means 98% of JC users ARE NOT going to turbo their cars, which means the info is useless to all but 2%. again, a situation where you should spend a little more time digesting the info before you hit the reply button.

so then the lord saw the light, and it was good (or some other weird rant)

No I am not upset as my comments are not flawed, you know what I mean when I say you lose bottom end or rather the torque curve is shifted etc.

I admit I missed the point about 98% not using turbo's.

The info is not useless, only to you.

[TI3VOM]

No I am not upset as my comments are not flawed, you know what I mean when I say you lose bottom end or rather the torque curve is shifted etc.

I admit I missed the point about 98% not using turbo's.

The info is not useless, only to you.

I'll bring this thread back to life, to let you know that the info to this thread is useless to me as well!

[vsv6dude]

Why bring it back to life if its useless ?