Headers and cats
Discussion
So, I need an idiots guide to all this business of headers and cats. Something I'm hoping to do later in the year but wanted some guidance.
My car: big boot Monaro LS1 VXR. K&N panel filter and (early) Wortec cat back exhaust (centre silencers removed)
Aim: sounds, slightly more power. Car is a daily driver and so needs to be useable in all conditions (ie speed bumps etc which are not a problem currently). I love the sound of some of the members cars on here and know that a lot of you have already done these mods.
So I've read around the forum about stainless headers and hi flow cats, and have also seen various people selling these. I've had quotes etc, but I want to understand what they do and why (Neil will confirm that I ask too many questions on this sort of stuff).
So what are the advantages and disadvantages of removing the standard (factory) ones I have?
Where to source?
And what's the difference between long/medium and shorties?
I'm aware long tube headers will need more work to fit (been told about an engine torque damper??), so thought medium ones would be a reasonable compromise. I've seen AAS do them as am off the shelf package, as do Wortec, but what about the stuff from the US and Oz? They seem to be cheaper, and whilst I don't want the cheapest option I want something that isn't going to break the bank but is still good quality.
Oh and future upgrade plans...not sure. At the moment none, but I said that nearly a year ago when I bought the car.
Got some other bits need doing to the car first, but hopefully the latter part of 2014 will be louder than the former part.
My car: big boot Monaro LS1 VXR. K&N panel filter and (early) Wortec cat back exhaust (centre silencers removed)
Aim: sounds, slightly more power. Car is a daily driver and so needs to be useable in all conditions (ie speed bumps etc which are not a problem currently). I love the sound of some of the members cars on here and know that a lot of you have already done these mods.
So I've read around the forum about stainless headers and hi flow cats, and have also seen various people selling these. I've had quotes etc, but I want to understand what they do and why (Neil will confirm that I ask too many questions on this sort of stuff).
So what are the advantages and disadvantages of removing the standard (factory) ones I have?
Where to source?
And what's the difference between long/medium and shorties?
I'm aware long tube headers will need more work to fit (been told about an engine torque damper??), so thought medium ones would be a reasonable compromise. I've seen AAS do them as am off the shelf package, as do Wortec, but what about the stuff from the US and Oz? They seem to be cheaper, and whilst I don't want the cheapest option I want something that isn't going to break the bank but is still good quality.
Oh and future upgrade plans...not sure. At the moment none, but I said that nearly a year ago when I bought the car.
Got some other bits need doing to the car first, but hopefully the latter part of 2014 will be louder than the former part.
VinceM said:
So, I need an idiots guide to all this business of headers and cats. Something I'm hoping to do later in the year but wanted some guidance.
My car: big boot Monaro LS1 VXR. K&N panel filter and (early) Wortec cat back exhaust (centre silencers removed)
Aim: sounds, slightly more power. Car is a daily driver and so needs to be useable in all conditions (ie speed bumps etc which are not a problem currently). I love the sound of some of the members cars on here and know that a lot of you have already done these mods.
So I've read around the forum about stainless headers and hi flow cats, and have also seen various people selling these. I've had quotes etc, but I want to understand what they do and why (Neil will confirm that I ask too many questions on this sort of stuff).
So what are the advantages and disadvantages of removing the standard (factory) ones I have?
Where to source?
And what's the difference between long/medium and shorties?
I'm aware long tube headers will need more work to fit (been told about an engine torque damper??), so thought medium ones would be a reasonable compromise. I've seen AAS do them as am off the shelf package, as do Wortec, but what about the stuff from the US and Oz? They seem to be cheaper, and whilst I don't want the cheapest option I want something that isn't going to break the bank but is still good quality.
Oh and future upgrade plans...not sure. At the moment none, but I said that nearly a year ago when I bought the car.
Got some other bits need doing to the car first, but hopefully the latter part of 2014 will be louder than the former part.
Only disadvantage is ground clearance with long tubes. Oh and possibly emissions if you get too excited with the cats, but this can probably be tuned.My car: big boot Monaro LS1 VXR. K&N panel filter and (early) Wortec cat back exhaust (centre silencers removed)
Aim: sounds, slightly more power. Car is a daily driver and so needs to be useable in all conditions (ie speed bumps etc which are not a problem currently). I love the sound of some of the members cars on here and know that a lot of you have already done these mods.
So I've read around the forum about stainless headers and hi flow cats, and have also seen various people selling these. I've had quotes etc, but I want to understand what they do and why (Neil will confirm that I ask too many questions on this sort of stuff).
So what are the advantages and disadvantages of removing the standard (factory) ones I have?
Where to source?
And what's the difference between long/medium and shorties?
I'm aware long tube headers will need more work to fit (been told about an engine torque damper??), so thought medium ones would be a reasonable compromise. I've seen AAS do them as am off the shelf package, as do Wortec, but what about the stuff from the US and Oz? They seem to be cheaper, and whilst I don't want the cheapest option I want something that isn't going to break the bank but is still good quality.
Oh and future upgrade plans...not sure. At the moment none, but I said that nearly a year ago when I bought the car.
Got some other bits need doing to the car first, but hopefully the latter part of 2014 will be louder than the former part.
Otherwise, short, mid, long all flow better than the stock cast iron jobbies. An engine is an air pump, having the exit flow better means it'll be able to pump the air more effectively. Simples.
They also look much nicer, weigh a tiny bit less, and most importantly, SOUND GREAT.
There are many arguments and conflicting opinions about what primary length is better and how much difference it makes, but really unless you're going for ultimate power from an NA engine, it's not going to make a big seat of the pants difference whatever you do.
US = steering column on wrong side, so won't fit without hammers.
Aus should fit nicely, shipping will be expensive, and if you have any problems with them, it's a long way to send them back...
Generally it's Monkfish/Walkinshaw/AAS depending on your location, AAS are the most reasonably priced I believe, but are in Newcastle.
Hi Vince,
I have been doing some research also on this as if I make mine loud enough, we can have a stereo shock wave pulsing around Medway
In all seriousness though, as mentioned already, the US parts are affected by the steering wheel being on the wrong side, though my understanding was this was more to do with the long tube (as there's more pipework to get in the way of stuff), whereas shorties probably would be ok. Also, I thought shorties were better for high end/top end RPM power gains, whereas long tube were better for low end torque/power gains, with mid length headers obviously being somewhere in the middle. Changing the CATS to high flow 200 or better 100 cell cats makes a big flow difference and would probably be where most of the gains come from with a corresponding very large increase in noise! Also understand those with 100 cell CATS sometimes struggle getting them up to temperature (more of an issue come MOT time) but just need to do a nice long high speed run on the way to the test centre. I'm sure some of the more techie people will correct the no doubt numerous errors, but hopefully most of it was fairly accurate from what I've found on in my own research musings......
I can't honestly imagine driving around in a car much louder than mine is already (Wortec cat back - no silencers), however, now its not a daily driver, I am thinking, hmm, well maybe a bit more noise wouldn't hurt.....
I have been doing some research also on this as if I make mine loud enough, we can have a stereo shock wave pulsing around Medway
In all seriousness though, as mentioned already, the US parts are affected by the steering wheel being on the wrong side, though my understanding was this was more to do with the long tube (as there's more pipework to get in the way of stuff), whereas shorties probably would be ok. Also, I thought shorties were better for high end/top end RPM power gains, whereas long tube were better for low end torque/power gains, with mid length headers obviously being somewhere in the middle. Changing the CATS to high flow 200 or better 100 cell cats makes a big flow difference and would probably be where most of the gains come from with a corresponding very large increase in noise! Also understand those with 100 cell CATS sometimes struggle getting them up to temperature (more of an issue come MOT time) but just need to do a nice long high speed run on the way to the test centre. I'm sure some of the more techie people will correct the no doubt numerous errors, but hopefully most of it was fairly accurate from what I've found on in my own research musings......
I can't honestly imagine driving around in a car much louder than mine is already (Wortec cat back - no silencers), however, now its not a daily driver, I am thinking, hmm, well maybe a bit more noise wouldn't hurt.....
Although in theory shorties are more suited to high rpm, it appears when actually fitted to cars and tested, the long tubes don't really lose anything up top to really give the shorties any advantage.
Also, because of the firing order on a V8, having them equal length apparently isn't as important as on other cylinder configurations.
It seems collector size / length is more important than people give it credit for.
Diameter too, some argue going too big means you lose air flow velocity at low rpm, costing torque. So for example on a sub 600bhp NA car, having 1 7/8" may lose torque compared to an otherwise identical 1 3/4" set. Finding actual dyno evidence of this seems impossible though, there's always something else that's changed, a different design, different collector, different tune, different time etc. etc. Plus most people believe that the option they've gone for is the right one...
It's a minefield of conflicting information out there to be honest...
But ultimately, it'll sound better and maybe have a few more ponies, so not worth getting all worked up about!
Also, because of the firing order on a V8, having them equal length apparently isn't as important as on other cylinder configurations.
It seems collector size / length is more important than people give it credit for.
Diameter too, some argue going too big means you lose air flow velocity at low rpm, costing torque. So for example on a sub 600bhp NA car, having 1 7/8" may lose torque compared to an otherwise identical 1 3/4" set. Finding actual dyno evidence of this seems impossible though, there's always something else that's changed, a different design, different collector, different tune, different time etc. etc. Plus most people believe that the option they've gone for is the right one...
It's a minefield of conflicting information out there to be honest...
But ultimately, it'll sound better and maybe have a few more ponies, so not worth getting all worked up about!
Hi,
I have JBA shortie headers from the US and they don't foul the steering at all. The advantage being that they can be fitted as a direct replacement for cast headers and therefore existing exhausts (aftermarket or production) will fit back without modification.
in my case I had a custom 2.5" fully stainless exhaust made including 100 cell cats and then got the stainless JBA from the US for about $600 including ceramic coating, at a later date.
I have JBA shortie headers from the US and they don't foul the steering at all. The advantage being that they can be fitted as a direct replacement for cast headers and therefore existing exhausts (aftermarket or production) will fit back without modification.
in my case I had a custom 2.5" fully stainless exhaust made including 100 cell cats and then got the stainless JBA from the US for about $600 including ceramic coating, at a later date.
An example only,,, you can see the difference in coated or raw stainless
http://www.summitracing.com/int/search/brand/jba-h...
http://www.summitracing.com/int/search/brand/jba-h...
I've been looking at these...
http://www.capa.com.au/prices_exhaust.htm
and these (just headers and cats). UK based but not sure on branding, they used to supply Defilippo but not sure if they still do. Haven't checked the price yet
http://www.lsv8power.co.uk/vxr8_exhaust_for_sale.p...
http://www.capa.com.au/prices_exhaust.htm
and these (just headers and cats). UK based but not sure on branding, they used to supply Defilippo but not sure if they still do. Haven't checked the price yet
http://www.lsv8power.co.uk/vxr8_exhaust_for_sale.p...
fastbikes76 said:
ARAF said:
Pontiac G8 GT 
Cheers,next Question...shorty's keep the stock cats yes ? Also where do guys find high flow cats or cat replacement pipes for the R8, being new to the cars my search mojo is just not there yet
The Hofff said:
I've been looking at these...
http://www.capa.com.au/prices_exhaust.htm
and these (just headers and cats). UK based but not sure on branding, they used to supply Defilippo but not sure if they still do. Haven't checked the price yet
http://www.lsv8power.co.uk/vxr8_exhaust_for_sale.p...
Not allowed to say negatives here but YHM which I suggest you read!http://www.capa.com.au/prices_exhaust.htm
and these (just headers and cats). UK based but not sure on branding, they used to supply Defilippo but not sure if they still do. Haven't checked the price yet
http://www.lsv8power.co.uk/vxr8_exhaust_for_sale.p...
Just keep in mind the only real upgrade for an LS1 VXR is longtubes, as it already comes with a set of shorties as standard. Unlike the LS2 which comes with stock manifolds.
Also seen plenty of dyno evidence to prove that 1 7/8 on an otherwise stock LS1 do produce better figures than the smaller 1 3/4. It's not much a few HP at the higher end, but it's the same low end in reality. Yet obviously the gap will change as other mods are installed.
What I am planning to do with my own LS1 VXR.
Also seen plenty of dyno evidence to prove that 1 7/8 on an otherwise stock LS1 do produce better figures than the smaller 1 3/4. It's not much a few HP at the higher end, but it's the same low end in reality. Yet obviously the gap will change as other mods are installed.
What I am planning to do with my own LS1 VXR.
wozzza said:
Just keep in mind the only real upgrade for an LS1 VXR is longtubes, as it already comes with a set of shorties as standard. Unlike the LS2 which comes with stock manifolds.
Also seen plenty of dyno evidence to prove that 1 7/8 on an otherwise stock LS1 do produce better figures than the smaller 1 3/4. It's not much a few HP at the higher end, but it's the same low end in reality. Yet obviously the gap will change as other mods are installed.
What I am planning to do with my own LS1 VXR.
Do you know who you will be using for this work? Also seen plenty of dyno evidence to prove that 1 7/8 on an otherwise stock LS1 do produce better figures than the smaller 1 3/4. It's not much a few HP at the higher end, but it's the same low end in reality. Yet obviously the gap will change as other mods are installed.
What I am planning to do with my own LS1 VXR.
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