Header Install
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
Tech Contributor
Joined: Oct 2011
Posts: 525
Likes: 9
From: Annapolis MD
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
Tech Contributor
Joined: Oct 2011
Posts: 525
Likes: 9
From: Annapolis MD
You can do the same thing (decreasing under hood temps and increasing efficiency) by having the headers ceramic coated inside and out.
That is what Jet Hot coating is, and is what it does. It also looks a whole lot better than header wrap.
Intermediate
Joined: Apr 2012
Posts: 35
Likes: 0
From: Wentzville Missouri
I read and read, and have not reached a decisive conclusion on manufacturer. Hedman,Hooker,OBX,and others. What is a good set of headers that isn't going to cost a small fortune, and where is a good place to get them? I see people speak of $200 cheapys (I do not think they exist for the c4) up to $1700 fancy jobs for show cars.
I want some that won't rust away in a year, that tuck away, don't hang down and hit every driveway curb, and don't require a vital organ as a downpayment. Really, just a set of regular old headers for street use and to **** off the neighbors when necessary.
So...much...information.........must.... .....continue........to.........read.... ...forum..........
Last edited by Mo'Vette; May 25, 2012 at 12:55 AM.
Instructor
Joined: Oct 2009
Posts: 195
Likes: 7
From: Tucson
I have an 85 also. I got a set of cheapie hedman's from Amazon open-box for $124 shipped. Couldn't turn it down. I used extra tall jack stands and they went in fairly easy from the bottom. I had the reducer that came with the headers expanded to 2.5", and then welded an O2 bung to it. Then I tied this into the stock exhaust pipe. I put in a new O2 sensor while I had it out. They're so cheap you might as well do it.
If I did it again, I would use a Hedman extension that already has an O2 bung like this:
http://www.summitracing.com/parts/HED-18708/
It would make it a lot easier to tie into the exhaust. With the s-bend you'll be able to fit it to the stock exhaust pipe by just rotating it.
Oh, and be VERY careful removing the dipstick or you'll break it. Don't ask me how I know this
Overall, they fit really well and work great for having about $175 total with everything. After I put the headers in I replaced the stocker starter with a mini-starter, and it slipped right in without touching the headers. Also, they don't hang down to low. I haven't hit them on anything yet. I couldn't be happier.
If I did it again, I would use a Hedman extension that already has an O2 bung like this:
http://www.summitracing.com/parts/HED-18708/
It would make it a lot easier to tie into the exhaust. With the s-bend you'll be able to fit it to the stock exhaust pipe by just rotating it.
Oh, and be VERY careful removing the dipstick or you'll break it. Don't ask me how I know this
Overall, they fit really well and work great for having about $175 total with everything. After I put the headers in I replaced the stocker starter with a mini-starter, and it slipped right in without touching the headers. Also, they don't hang down to low. I haven't hit them on anything yet. I couldn't be happier.
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Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Not hard at all with the car up in teh air, at least 12" from the hgroudnd to the frame,,,
AND, you "really should" buy the 1996 Vette mini starter because the stocker is to large and too close to teh header which results in heat soke.
Just sayin, one thing,,,, leads to,, ,aaanoothhherrr, (The Fixx)
Drive over here to INDY and we can do it in my garage,,,
AND, you "really should" buy the 1996 Vette mini starter because the stocker is to large and too close to teh header which results in heat soke.
Just sayin, one thing,,,, leads to,, ,aaanoothhherrr, (The Fixx)
Drive over here to INDY and we can do it in my garage,,,
Drifting
Joined: Mar 2009
Posts: 1,253
Likes: 4
From: East Wenatchee (2hours from n e where) WA
O2 senors; Could be a good idea to fire up new headers with a old or even no sensor to avoid cruding the thing up with paint oil sealant ect burnoff inside the header.
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
and you could get a heated O2 as welll1 thing,,,, leads to another
http://www.youtube.com/watch?v=z17CiM2a1M4
Instructor
Joined: Oct 2009
Posts: 195
Likes: 7
From: Tucson
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
Ok lets say I do some decent headers with a 3" collector. If i decided to do a 58mm Throtole body will i need to re flash my chip or upgrade my Injectors?
How much can i expect to gain by these 2 mods?
I am planning to do a Dyno run every step of the way
Curious if I am on the right track
Planed Mods in this order
Headers 3" exhaust no cats
58mm TB
zz7 Cam
Re built alum heads
Reverse water pump (eliminate the air pump and AC)
That will be all till i re do the bottom end. as for now it has a touch under 100k on it and seems to sound ok and does not shoot oil
How much can i expect to gain by these 2 mods?
I am planning to do a Dyno run every step of the way
Curious if I am on the right track
Planed Mods in this order
Headers 3" exhaust no cats
58mm TB
zz7 Cam
Re built alum heads
Reverse water pump (eliminate the air pump and AC)
That will be all till i re do the bottom end. as for now it has a touch under 100k on it and seems to sound ok and does not shoot oil
Intermediate
Joined: Apr 2012
Posts: 35
Likes: 0
From: Wentzville Missouri
3" dual exhaust seems a bit excessive. 2.25" or 2.5" is overly plenty for any small block, bored, stroked oreven blown. The 3" pipes are for big block high performancedisplacement.
I am getting ready to bring my 87 c4 in, talked with a lot of performance guys, and they all told me the same thing. The overkill will not give any improvement, and in some cases can actually hinder performance.
Just my 2 bits.
I am getting ready to bring my 87 c4 in, talked with a lot of performance guys, and they all told me the same thing. The overkill will not give any improvement, and in some cases can actually hinder performance.
Just my 2 bits.
Intermediate
Joined: Apr 2012
Posts: 35
Likes: 0
From: Wentzville Missouri
http://www.mk5cortinaestate.co.uk/calculator5.php
here you go, this one is based on HP to exhaust requirement. there are others that calculate for displacement, rpm range, forced induction, etc, but they come up pretty much the same.
here you go, this one is based on HP to exhaust requirement. there are others that calculate for displacement, rpm range, forced induction, etc, but they come up pretty much the same.
Burning Brakes
Joined: May 2008
Posts: 1,008
Likes: 5
From: Greensburg PA
The TB air flow isn't the limiting factor on our cars, the TPI intake system is. You can stuff as much air as you want through the TB, but it's still gonna choke up through the long runners.
If you search there's CFM numbers for stock and aftermarket TB's with and without the airfoil.
If you search there's CFM numbers for stock and aftermarket TB's with and without the airfoil.
Race Director
Joined: May 2003
Posts: 10,749
Likes: 41
http://www.mk5cortinaestate.co.uk/calculator5.php
here you go, this one is based on HP to exhaust requirement. there are others that calculate for displacement, rpm range, forced induction, etc, but they come up pretty much the same.
here you go, this one is based on HP to exhaust requirement. there are others that calculate for displacement, rpm range, forced induction, etc, but they come up pretty much the same.
I would go a tad bigger then smaller, and I think that's normal thinking when thinking of exhaust.
I have true dual 3 inch mandrel bent and will prob make 530chp/575tq when exhaust is fixed and fully tuned.
According to the link I need 2.54.
If you type in 300 hp (LT1) it spits out 1.91 inches, and if you type in 240 hp (L98) it spits out 1.71 which seems awful small!!