EXHAUST QUESTIONS ANSWERED BY AN EXHAUST TECH

[EXHAUSTFIX]

I'd also love to know if the flexy braid things are a requirement.
Person who did the exhaust did not install one.
truck is an 80 series.
Burnsy

if you have extractors on your 80 series you should not need one

[awill4x4]

I made up tube headers for my B/Block 80 ute years ago out of mild steel tubing and had them HPC hi-temp coated. I have had bad problems with the pipes constantly cracking, im always rewelding and having to pull the pipes off to do it some times. Ive made headers before but being my own 4B had them coated for corrosion resistance mainly. Have heard this to be a problem on exhausts when coated as the pipes run real hot and is a common problem, i also wonder what it does to the steels chemical properties. I am contemplating making a new set but this time in stainless but have had a lot to do with stainless pipe ( Im a maint supv in a steel mill ) and over time the stainless suffers from fatigue cracking. I need the corrosion resistance as the 80ute is a recreational 4B so dosent see regular mon-fri use gets moved around the shed and has the typical mud encrusted moisture absorbing exhaust coating. Mild steel pipes uncoated dont last too long under these conditions so thats why looking at stainless and prepared to go to the expense on materials and full tig weld them but would like to be sure im doing the right thing.
wally

Wally, my understanding about stainless headers is that grade 321 is the best grade to use, it can be hard to find but it is available. Burns Stainless in the USA recommend 321 grade or Inconel (but that's REALLY expensive stuff) and they make the most beautiful merge collectors you'll ever see. Check out their website at http://burnsstainless.com/ there's lots of good tech info there on exhausts, header theory, header construction, different materials and their uses etc in their "technical articles" page.
Regards Andrew.

[patrolpaul]

Thanks EXHAUSTFIX. Do you have a shop in Melbourne?

[EXHAUSTFIX]

Thanks EXHAUSTFIX. Do you have a shop in Melbourne?

yes 14 windsor rd croydon
ph 97229766

[nicbeer]

Hey ross,

I have a sierra with 1.3, extractors,modded cam and toyota carb.

i have a 2" pipe and straight thru turbo muffler on it. is this the best way to go for allround power/torque benefits.

cheers

do not go any bigger with that small engine
the only thing you might be able to try is make your secondry pipes on the extractors about 14" long that may help a bit

Cheers/ I will have a look

[frp88]

if got a 13bt and was thinking 3" its a factory turbo and after the bigger tube is i would like to boost it up to 12psi with inter.

if you are thinking of upgrading to 12 lb boost you are right on the mark for needing a 3" system
any where near 1 bar of boost warrents this size

thanks

[sjp]

hi i have a na 105 100 series,how much if any does extractors and a 2 1/2 system help with the preformance and power

[EXHAUSTFIX]

hi i have a na 105 100 series,how much if any does extractors and a 2 1/2 system help with the preformance and power

hi
im not sure if you mean v8 or 6 cyl
but if its a 100 ser v8 man what a difference chalk and cheese
the v8 transforms from a heavy not real quick 4wd to almost like driving
something that has just had $10,ooo spent on the engine

the 6cyl not quite as noticiable rule of thumb is usually about a ten percent increase or if its on lpg it usually brings your power back to about where you would be on petrol

[zzzz]

Ross,

Thanks for dropping into outerlimits I am sure everyone appreciates it greatly.

I have a couple of questions regarding different cars...

Jeep Wrangler - 4.0 litre straight six
I currently have hitech extractors, then 2.5" pipe with straight through muffler and hi flow cat.
The hitech were chosen as they wrap around the sump rather than under it.
Would you change this system at all for more power?
I have plans to turbo or supercharge the motor and was wondering if this setup would be ok?

Nissan skyline - 2.5 litre straight six stock turbo and approx 190-200kw atw
Currently running a 3" dump to a high flow cat and then 3.5" to a single muffler with a single 3.5" tip
Would you change this setup at all?
Would a split dump be beneficial for my setup
I would prefer to get a muffler with dual 2" tips to make it look more stock rather than the big coffee can look it has now
Would the dual tip muffler be ok?

Gen III LS1 from VY SS ute - 255kw
The application for this is a rockcrawling buggy.
There are no restrictions on intake or exhaust but there are space considerations as the buggies are made with tight tolerance between frame and motor.
Assuming a single short pipe from extractors back was wondering what size pipe and muffler would be best?
There is probably not much choice with extractors as space is at a premium here.
They may even end up with the drivers side bank wrapping around the front of the motor to join the other bank


Thanks in advance.

Zach

[EXHAUSTFIX]

Ross,

Thanks for dropping into outerlimits I am sure everyone appreciates it greatly.

I have a couple of questions regarding different cars...

Jeep Wrangler - 4.0 litre straight six
I currently have hitech extractors, then 2.5" pipe with straight through muffler and hi flow cat.
The hitech were chosen as they wrap around the sump rather than under it.
Would you change this system at all for more power?
I have plans to turbo or supercharge the motor and was wondering if this setup would be ok?

Nissan skyline - 2.5 litre straight six stock turbo and approx 190-200kw atw
Currently running a 3" dump to a high flow cat and then 3.5" to a single muffler with a single 3.5" tip
Would you change this setup at all?
Would a split dump be beneficial for my setup
I would prefer to get a muffler with dual 2" tips to make it look more stock rather than the big coffee can look it has now
Would the dual tip muffler be ok?

Gen III LS1 from VY SS ute - 255kw
The application for this is a rockcrawling buggy.
There are no restrictions on intake or exhaust but there are space considerations as the buggies are made with tight tolerance between frame and motor.
Assuming a single short pipe from extractors back was wondering what size pipe and muffler would be best?
There is probably not much choice with extractors as space is at a premium here.
They may even end up with the drivers side bank wrapping around the front of the motor to join the other bank


Thanks in advance.

Zach

JEEP
with this jeep the system is pefect for normaly asperated
if you supercharge it you may have to run 3"
if you turbo it you will have to disgard the extractors and get a turbo manifold made and also run 3 inch

SKILINE
if you want max power from this car you could split the dump pipe as close to the turbo as possiable then run twin 2.5"system with stait through mufflers 2in 2out style in the front and rear you may hve to get the front muffler made but thats not hard

GEN111

it would be a good idea to try to get some sort od extractors made for this
if it is only a short sustem you would run twin 2.25" with 2 large strait through mufflers and an x pipe in the system

[MARKx4]

With the fuerl injected 5ltr commodore, im considering on putting on extractors what is a good brand to use. The rest of the system is going to be twin cat into twin exhaust with crossover running the twin pipes all the way to the rear. Im looking at 2 1/4 pipe, is that big enough. My goal is to have it running between 350 to 400hp and as daily driver.

[EXHAUSTFIX]

With the fuerl injected 5ltr commodore, im considering on putting on extractors what is a good brand to use. The rest of the system is going to be twin cat into twin exhaust with crossover running the twin pipes all the way to the rear. Im looking at 2 1/4 pipe, is that big enough. My goal is to have it running between 350 to 400hp and as daily driver.

the extractors to use on this are pacemaker 5000d
the setup for the system is ok dont go any bigger than 2.25' on a 5 ltr this is exactly the right size and defently run twin cats but make sure
you get full metal substrate cats as ceramic ones wont take that sort of h/power
thanks
ross

[RoldIT]

Great tech, Ross!

Don't give away all your secrets though ...

[EXHAUSTFIX]

Great tech, Ross!

Don't give away all your secrets though ...

thank you for your vote of confidence
i realy dont mind trying to give the forum my help on exhausts
there are a lot of dodgy exhaust shops out there so i like those who are about to get work done to be well informed so they dont get ripped off
or for those in melbourne im happy to do the work for them myself

thanks all
ross

[RoldIT]

Actually, just for arguments sake ...

Mandrel bends vs Crush Bends?

In the example of a turbo diesel, let's assume stock to mildly worked, is an exhaust of the same size (ie both 3") going to have a significant performance difference if built using mandrel bends instead of the standard old crush bends.

I understand the mandrel bends in a hiflow, hi performance motor would be worth while as every little bit helps the hp figures, but in the lower end of the performance stakes is it worth it to build with mandrel?

Cheers.

[EXHAUSTFIX]

Actually, just for arguments sake ...

Mandrel bends vs Crush Bends?

In the example of a turbo diesel, let's assume stock to mildly worked, is an exhaust of the same size (ie both 3") going to have a significant performance difference if built using mandrel bends instead of the standard old crush bends.

I understand the mandrel bends in a hiflow, hi performance motor would be worth while as every little bit helps the hp figures, but in the lower end of the performance stakes is it worth it to build with mandrel?

Cheers.

ok on a normaly asperated engine a little restriction is a good thing to not upset where your max torque is in your rev range you do not want it going up in the revs

with a turbo your torque is usually created by having a short manifold with a turbo hanging of it this should give you backpresure and help your torque

so after the turbo outlet i would always mandrel bend the pipe for max flow

ross

[RoldIT]

Cool, that sounds fair enough to me. I assume you have the facilities to fabricate using mandrel bends?

Thanks for the info.

[EXHAUSTFIX]

Cool, that sounds fair enough to me. I assume you have the facilities to fabricate using mandrel bends?

Thanks for the info.

yes i own an exhaust shop
ph 0397229766

[RoldIT]

Cool, that sounds fair enough to me. I assume you have the facilities to fabricate using mandrel bends?

Thanks for the info.

yes i own an exhaust shop
ph 0397229766

Cheers, I was aware of that, I just wasn't sure if EVERY exhaust shop worked with mandrel bends or not.

By the way, if you work with stainless, you can probably get a bit of work from around here making custom stainless snorkels for 4WDs if you are prepared to do that sort of work. Stainless snorkels are pretty popular lately ... just a thought.

[EXHAUSTFIX]

Cool, that sounds fair enough to me. I assume you have the facilities to fabricate using mandrel bends?

Thanks for the info.

yes i own an exhaust shop
ph 0397229766

Cheers, I was aware of that, I just wasn't sure if EVERY exhaust shop worked with mandrel bends or not.

By the way, if you work with stainless, you can probably get a bit of work from around here making custom stainless snorkels for 4WDs if you are prepared to do that sort of work. Stainless snorkels are pretty popular lately ... just a thought.

yes i do work with stainless steel i could make snorkels but i would not cut the hole in the guard that would be up to the owner

[RoldIT]

Cool, that sounds fair enough to me. I assume you have the facilities to fabricate using mandrel bends?

Thanks for the info.

yes i own an exhaust shop
ph 0397229766

Cheers, I was aware of that, I just wasn't sure if EVERY exhaust shop worked with mandrel bends or not.

By the way, if you work with stainless, you can probably get a bit of work from around here making custom stainless snorkels for 4WDs if you are prepared to do that sort of work. Stainless snorkels are pretty popular lately ... just a thought.

yes i do work with stainless steel i could make snorkels but i would not cut the hole in the guard that would be up to the owner

Yep, fair enough. No shortage of people around here prepared to hack their rigs to bits ...

[MARKx4]

With the fuerl injected 5ltr commodore, im considering on putting on extractors what is a good brand to use. The rest of the system is going to be twin cat into twin exhaust with crossover running the twin pipes all the way to the rear. Im looking at 2 1/4 pipe, is that big enough. My goal is to have it running between 350 to 400hp and as daily driver.

the extractors to use on this are pacemaker 5000d
the setup for the system is ok dont go any bigger than 2.25' on a 5 ltr this is exactly the right size and defently run twin cats but make sure
you get full metal substrate cats as ceramic ones wont take that sort of h/power
thanks
ross

Thanks for the reply, i was aiming at getting stainless steel cats and mufflers. Will the SS cats be full metal or can you get ceramic ones, just so i know when ordering.

[murcod]

Hi Ross,

What are your thoughts on exhaust header wrap tape? There seems to be plenty of negative feedback regarding it reducing the life of the headers? What other options are there for reducing heat off extractors / headers - apart from HPC style coatings (I don't want to have to remove the extractors....)

Thanks!

[Rb25sil80]

Ross,

Thanks for dropping into outerlimits I am sure everyone appreciates it greatly.

I have a couple of questions regarding different cars...

Jeep Wrangler - 4.0 litre straight six
I currently have hitech extractors, then 2.5" pipe with straight through muffler and hi flow cat.
The hitech were chosen as they wrap around the sump rather than under it.
Would you change this system at all for more power?
I have plans to turbo or supercharge the motor and was wondering if this setup would be ok?

Nissan skyline - 2.5 litre straight six stock turbo and approx 190-200kw atw
Currently running a 3" dump to a high flow cat and then 3.5" to a single muffler with a single 3.5" tip
Would you change this setup at all?
Would a split dump be beneficial for my setup
I would prefer to get a muffler with dual 2" tips to make it look more stock rather than the big coffee can look it has now
Would the dual tip muffler be ok?

Gen III LS1 from VY SS ute - 255kw
The application for this is a rockcrawling buggy.
There are no restrictions on intake or exhaust but there are space considerations as the buggies are made with tight tolerance between frame and motor.
Assuming a single short pipe from extractors back was wondering what size pipe and muffler would be best?
There is probably not much choice with extractors as space is at a premium here.
They may even end up with the drivers side bank wrapping around the front of the motor to join the other bank


Thanks in advance.

Zach

Cant help you on the 1st and 3rd but having owned several rb25 powered machines Id say you are right on the money with your current setup to be honest. The only different, I ran what you are referring to as a "double dump" This is where they welded a tongue into the dump pipe off the turbo outlet to effectively split the wastegate gas and the turbine outlet gas. These 2 pipes joined up about 16 inches down the exhaust system. My system was 3 inch down to a gutted cat and a 4 inch straight thru hks muffler. If your in Brisbane I can highly recommend Exotic Exhaust at sumner park, they do alot of racecars and there work is very good and pricing is extremely competitive! They did my system for $300 as I supplied my own muffler and Cat. They also did the system on my Feroza and im quite happy with it.

Excuse the messiness of the engine bay, and those gay blue pipes but you can see the top pipe coming off the turbo, that is the seperate collector for the wastegate air. Cant believe I dont have a pic of the dump pipe off the car to be quite honest!

[img=http://img64.imageshack.us/img64/2779/dcp00202pm.th.jpg]

Cheers
Brad

PS. Exhaustfix: we are really lucky to have a guy like you on these boards now, you seem to be a wealth of exhaust information Been a good read.

[EXHAUSTFIX]

Hi Ross,

What are your thoughts on exhaust header wrap tape? There seems to be plenty of negative feedback regarding it reducing the life of the headers? What other options are there for reducing heat off extractors / headers - apart from HPC style coatings (I don't want to have to remove the extractors....)

Thanks!

hi
i have only had limited luck with heat wrap
it seams to make mild steel cristalise or go brittle
if it is a heat in the cab try riverting some acl ford heat shield material to the fire wall
if its under bonnet heat try to run an air duct from the front of the car into the eng bay to disperse the heat

[murcod]

... try riverting some acl ford heat shield material to the fire wall

Thanks for the tip on ACL- a quick Google found this stuff : http://www.aclperformance.com.au/prod_heatshield.htm

I'd already started making a heatshield of sorts out of stainless steel- some of that attached to it should be perfect.

[EXHAUSTFIX]

... try riverting some acl ford heat shield material to the fire wall

Thanks for the tip on ACL- a quick Google found this stuff : http://www.aclperformance.com.au/prod_heatshield.htm

I'd already started making a heatshield of sorts out of stainless steel- some of that attached to it should be perfect.

that stuff is the best it is good up to 850 deg

[The Fish]

Ross! Has been a great tech read and will continue to read and learn. Didn't realise there was so much tech involved with exhausts

[EXHAUSTFIX]

Ross! Has been a great tech read and will continue to read and learn. Didn't realise there was so much tech involved with exhausts

thank you

realy we are only scratching the surface when you get into verlocity flow rates gas speed v diamiter and heat factors controling the expansion and contraction of the gasses under different volumetric pressure thets when it gets real interesting

[80UTE]

HI THERE
I AM NEW TO THIS FORUM AND I THOUGHT IF I COULD HELP ANYONE HERE WITH THERE EXHAUST QUESTIONS OR PROBLEMS I WOULD ONLY BE TO HAPPY TO DO SO
MY NAME IS ROSS AND I HAVE BEEN AN EXHAUST TECH FOR OVER 30 YEARS
I LOVE TO SOLVE THE HARD PROBLEMS SO PLEASE FEEL FREE TO FIRE AWAY
THANKS

I made up tube headers for my B/Block 80 ute years ago out of mild steel tubing and had them HPC hi-temp coated. I have had bad problems with the pipes constantly cracking, im always rewelding and having to pull the pipes off to do it some times. Ive made headers before but being my own 4B had them coated for corrosion resistance mainly. Have heard this to be a problem on exhausts when coated as the pipes run real hot and is a common problem, i also wonder what it does to the steels chemical properties. I am contemplating making a new set but this time in stainless but have had a lot to do with stainless pipe ( Im a maint supv in a steel mill ) and over time the stainless suffers from fatigue cracking. I need the corrosion resistance as the 80ute is a recreational 4B so dosent see regular mon-fri use gets moved around the shed and has the typical mud encrusted moisture absorbing exhaust coating. Mild steel pipes uncoated dont last too long under these conditions so thats why looking at stainless and prepared to go to the expense on materials and full tig weld them but would like to be sure im doing the right thing.

wally

nice question wally
ok no1 use a 10mm plate
no2 use 316 stainless steel
no3 tig weld all joints do not grind back welds
no4 make pipes go in to collector cone in firing order or rotation 1 to 4 in firing order
do no hang the exhaust to ridged make sure you have plenty of movement on the rubber mountd
at the back of the collector cones
make up solid plate mounts and attach to gearbok
if your making your own collector cones put a point inside them
your cracking is due to vibration and sagging under heat
if you do all this you should have no problim

i have a simular setup on the new ford focus world series rally car and that does not brake
thanks for the brain drain
ross

Thanks for the great info your a regular information cow and the milking wont stop till your dry. My current headers are a 4-2-1 1 7/8' primary tubes into 2 1/2 engine pipes then 3 1/2' muffler and exhaust sytem the whole system is constructed from mandrel bent tubing. Ive since fitted a bigger cam, Holley EFI inlet manifold and Bowtie GM Performance alloy heads. I have been advised to go to 2' primary tubes and plan on on making the pipes a 4-1 configuration as in the 80 ute this may be a more sturdy construction. Would 4 2' pipes into a 2 1/2' collector oulet be sufficient or would i need larger engine pipes. Ive looked into supporting the exhiaust on the gear box and will do that as well. Im looking into what 4-1 collectors are available in 316 stainless for when i make up the new pipes. On my original post i mensioned the HPC coating adding to the cracking problems and have come across others that have had the same problems , you being in the industry have you come accross this.

Wally