Headers

[Moanro5.7]

Hi guys

Right well at the weekend there i had ma car on a dyno and i cam in at about hp figure for a standard car.

So iam looking to make some changes and the first is the headers. I work in the motor trade and i deal with parts for cars right throw to trucks and busses. This gives me great contacts in the trade.

The first contact i have is a company called CRD (Calder Racing Development) I have a freind who works there and is a big Vauxhall nut I have just phoned him and said "i want 2 headers for my Monaro". The reply was "can u get me an exhaust manafold gasket" So iam looking to see if anyone has a old manafold gasket so we can use them as a template for the manafolds mounts. A pair would be even better

The car has a Wortec cat back system on it just now which i wanna continue to use.

(I have asked for theses manafolds to be an 1"3/4 or 44mm which is not a problem. But brings me onto ma second issue. As i work in the trade and have some good freinds throw the trade i could have this car decated and an MOT would not be a problem & if it became a problem i could just stick the old manafolds and cats back on.

So first off all is 1"3/4 manafolds the right way to go?

Second does anyone out there have a set of used or new manafold gaskets for a 5.7 LS1 VZ car?

Third will this car run without o2 sensors fitted.

Thanks for looking and your help

Si

Ps Kyle i have you inmind for a set too

[MyM8V8]

Moanro5.7 said:

Hi guys

Right well at the weekend there i had ma car on a dyno and i cam in at about hp figure for a standard car.

So iam looking to make some changes and the first is the headers. I work in the motor trade and i deal with parts for cars right throw to trucks and busses. This gives me great contacts in the trade.

The first contact i have is a company called CRD (Calder Racing Development) I have a freind who works there and is a big Vauxhall nut I have just phoned him and said "i want 2 headers for my Monaro". The reply was "can u get me an exhaust manafold gasket" So iam looking to see if anyone has a old manafold gasket so we can use them as a template for the manafolds mounts. A pair would be even better

The car has a Wortec cat back system on it just now which i wanna continue to use.

(I have asked for theses manafolds to be an 1"3/4 or 44mm which is not a problem. But brings me onto ma second issue. As i work in the trade and have some good freinds throw the trade i could have this car decated and an MOT would not be a problem & if it became a problem i could just stick the old manafolds and cats back on.

So first off all is 1"3/4 manafolds the right way to go?

Second does anyone out there have a set of used or new manafold gaskets for a 5.7 LS1 VZ car?

Third will this car run without o2 sensors fitted.

Thanks for looking and your help

Si

Ps Kyle i have you inmind for a set too

I assume your friends have CNC laser cutter for the flanges? If not you can buy just the flanges here:

http://www.stahlheaders.com/Frame%20Flanges.htm

[Moanro5.7]

Yeah i think so, He said just to get him a gasket and he can get the machine to cut them for me

But ill have a look at the link might be an idea to buy them in

[k15tox]

nice one mate, keep me informed!

[tinker-27]

hi i have header blanks in stock, they are high grade stainless steel,8mm thick, let me know if you need any cheers craig 07950399080

[ringram]

You might want new gaskets anyway, in which case you can loan them to him.

Anyway, you have asked the wrong question. Your question should be what size exhaust do I need to support my goal of X BHP.
Asking if a random header size will work with an unknown power output isnt going to achieve much.

If you just want to optimise the stock setup and no more, then your choice will be fine. How long are you going to make the primaries? Will you step them? What about a merge collector? Or will your mate sort that out for you?

Personally I recommend a 454 In which case you will want 2" primaries or 1-7/8" at least and a dual 3" exhaust.

Also quite how you intend not to run O2 sensors is a point for discussion. Do you realise that 99% of the time the ECU actually runs off the O2 sensors in closed loop? In which case if you remove the sensors your tune will need some serious attention to prevent crap fueling from possible wearing out of your engine. Thats ignoring all the warning lights and error codes that you will get up on your dash for the time being too.

Happy to help, but you need to start at the start, not the finish.

[Well_Fans]

hmm actually I suppose that engine I've got lying will have the gaskets under the stock headers, be easier to buy a new set if you want them this week though. Hope you included me in equation as a potential customer for him as well lol. For future proofing though you might be better looking at the 1 7/8th into a 3" collector as ringram mentioned, can always get a step down cat section to bolt up to your current exhaust. Can he do ceramic coating as well? Does he know or have you mentioned to him its easier if theres a split in 1 of the pipes on the driver side to get it in around the steering rack?

[Bonnie and Clyde]

Is there really so much to be gained on an LS1 with headers??? We havn't seen it

[gsd2000]

You were told the same as me mel, your car needs more air

[Monaro5.7]

ringram said:

You might want new gaskets anyway, in which case you can loan them to him.

Anyway, you have asked the wrong question. Your question should be what size exhaust do I need to support my goal of X BHP.
Asking if a random header size will work with an unknown power output isnt going to achieve much.

If you just want to optimise the stock setup and no more, then your choice will be fine. How long are you going to make the primaries? Will you step them? What about a merge collector? Or will your mate sort that out for you?

Personally I recommend a 454 In which case you will want 2" primaries or 1-7/8" at least and a dual 3" exhaust.

Also quite how you intend not to run O2 sensors is a point for discussion. Do you realise that 99% of the time the ECU actually runs off the O2 sensors in closed loop? In which case if you remove the sensors your tune will need some serious attention to prevent crap fueling from possible wearing out of your engine. Thats ignoring all the warning lights and error codes that you will get up on your dash for the time being too.

Happy to help, but you need to start at the start, not the finish.

This what i need to know rigram. My aim in all of this is to set up an exhaust system that will allow me to put a cam in the car and possibly new heads with all the upgrades. and by the looks of it all i should keep the cats in the system. So any input you have would be great. As i want to buy once and not have to touch the system again. and at the end of it to be looking between 400 to 500hp

I have put in a link to the company that my contact works for.

http://caldermotor.co.uk/

[Bonnie and Clyde]

gsd2000 said:

You were told the same as me mel, your car needs more air

Yeah thats right but what i'm saying is that adding headers doesn't really help BHP does it??

[Monaro5.7]

Well_Fans said:

hmm actually I suppose that engine I've got lying will have the gaskets under the stock headers, be easier to buy a new set if you want them this week though. Hope you included me in equation as a potential customer for him as well lol. For future proofing though you might be better looking at the 1 7/8th into a 3" collector as ringram mentioned, can always get a step down cat section to bolt up to your current exhaust. Can he do ceramic coating as well? Does he know or have you mentioned to him its easier if theres a split in 1 of the pipes on the driver side to get it in around the steering rack?

Here is a link to the company.

http://caldermotor.co.uk/

[Monaro5.7]

Bonnie and Clyde said:

gsd2000 said:

You were told the same as me mel, your car needs more air

Yeah thats right but what i'm saying is that adding headers doesn't really help BHP does it??

The air intake side i was thinking about an OTR and porting the throttle body.

[Monaro5.7]

tinker-27 said:

hi i have header blanks in stock, they are high grade stainless steel,8mm thick, let me know if you need any cheers craig 07950399080

Thanks craig. i might take you up on that offer.

[Well_Fans]

assume its crdracing.co.uk rather than the car sales side that you posted the link for lol

[after_shock]

Bonnie and Clyde said:

gsd2000 said:

You were told the same as me mel, your car needs more air

Yeah thats right but what i'm saying is that adding headers doesn't really help BHP does it??

Not directly but it does help torque ALOT which is basically your accelaration

[Monaro5.7]

Well_Fans said:

assume its crdracing.co.uk rather than the car sales side that you posted the link for lol

Yeah sorry

[ringram]

Hmm, in which case Id run a 1-7/8 header into dual 3" or dual 2.5" if you are replacing it anyway. Especially with heads and cam in the future. 2.5" is good for over 500fwhp. Just make sure you dont clog it with bad mufflers or cats.

You can take your cats out if you want which can help a tad, but you need to keep your front 2 o2 sensors. The back 2 can stay or go, but you might need to disable them in the ECU.

This is what you need to read http://www.superchevy.com/technical/engines_drivet...

[ringram]

Bonnie and Clyde said:

Is there really so much to be gained on an LS1 with headers??? We havn't seen it

Yes you have mate you have a good amount more torque. BHP = TQ * RPM /5252 so if you have more tq at a certain rpm point you have more BHP.

It just you dont have much more peak bhp, which means at max rpm the airmass in the cylinder isnt much more than before even though exhaust is improved. For that IMO you need to feed more air in by removing the restriction in the intake, see the other thread for some ideas.. Port your TB for one zero cost option.

[Monaro5.7]

ringram said:

Hmm, in which case Id run a 1-7/8 header into dual 3" or dual 2.5" if you are replacing it anyway. Especially with heads and cam in the future. 2.5" is good for over 500fwhp. Just make sure you dont clog it with bad mufflers or cats.

You can take your cats out if you want which can help a tad, but you need to keep your front 2 o2 sensors. The back 2 can stay or go, but you might need to disable them in the ECU.

This is what you need to read http://www.superchevy.com/technical/engines_drivet...

Thanks this is all good info. I have to get gaskets and then go see him. So if i have all the info i need before i go and see him i can get the right kit.