DarkKnight

The Hooker headers that are on my car are rusting out and I was going to just replace them with stainless long tubes. However, while looking up headers for my car I have been finding articles and posts stating that long tubes are not always the best way to go depending on application. For most street cars, shorty or midlength headers are recommended as they, aside from clearance, build power faster and it is available from low end to mid range where as long tubes are recommended for track/race because they sacrifice low end power and torque to make power and torque in the high end.
Is that true? I always thought that the better the exhaust breathes, the more power it makes?
Should I just stay with the Hookers I have?
I have a 94 Camaro with a 383 stroker making 11:8 to 1 compression with ported/polished heads and 3 angle valve job. It's just a fun car. Maybe see the track here and there if I'm lucky.
Thanks in advance for the info!

Injuneer

The theory says just the opposite... long tubes increase torque below peak torque (mid-range RPM), and reduce torque above peak torque (high RPM). Since HP is a product of torque x RPM, whatever you do to the torque also happens to the HP.

Here are references from "Hot Rod" magazine:

Header Basics - How Headers Contribute to Horsepower - Car Craft Magazine

How To Size Headers - Popular Hot Rodding Magazine

How to Pick the Right Header - Popular Hot Rodding Magazine

But then there is the real world. I've seen a dyno test of a small block Chevy engine that contradicted that.

Personally, a friend of mine was running a Vortech S/C 383 LT1. He was running a set of AS&M mid-lengths that had been modified on the left side to eliminate the twist back in front of the engine for the Y-pipe. In essence, they both pointed to the rear, and both had collector extensions. In dyno tests in the range the engine operated in at the track (5,000+ RPM), up to the 850 flywheel HP level, the AS&M's outperformed a set of Hooker long tubes. The HP difference was sizeable. That would seem to verify the theory.

But above 850 HP, ranging up to 1,125 HP, the Hooker LT's produced the most HP under the curve (at this point the engine was operating in the 5,000 - 8,000 RPM range). That contradicts the theory.

When he dumped the AS&M's, I jumped right on them, and they are still in use on my 381ci engine. Never compared them to anything else. But all the engine dyno tuning on my car was done with them in the system.

DarkKnight

That's great info, thanks!
That's why I am getting confused now about header selection and questioning what I wanted to do. Do you think I should stay with the Hookers I have now?
What is AS&M? Do recommend them for my motor?

Injuneer

AS&M is Arizona Speed & Marine. I don't think they sell them any more. The ones I have were originally installed in a 1997 30th SS convertible, in 1998. Unfortunately, ancient history. LT1 parts are becoming harder to find.

1993-97 F-Body LT1

DarkKnight

Figures... I remember because LT1s were new and parts were hard to find, now because LT1s are old parts are hard to find.
It seems your opinion is to use shorty style?

Injuneer

For a sreet car, LT's would seem best. More torque at low/mid RPM. The articles also indicate the advantage at low RPM of not going too big on primary diameter.

mzgp5x

I did use the SLP shorts on a 97SS MM6. The heat took out the fiberglass HVAC plenum on the driver side. Not an easy fit. Gasket a problem on the driver side. O2s very difficult to access.


Went to Pace LTs. Much better access under car for O2 sensors. Now, a much better solution for me. Used the stage-8 fasteners (very good). Did my own Y to a Mufflex cat back. EZ off/ on with weld on clamp(s) and tube end connection transitions.
B.

DarkKnight

I went with LLP long tube headers. 3rd production run which supposedly eliminates a lot of the problems previous buyers complained of. There are supposedly made of 321 stainless but that's a whole other story. They look good and are stepped with a merge collector. Waiting to put them on after winter breaks.

Injuneer

Were those the SLP CARB certified dual cat headers? They were notorious for excessive underhood heat, particularly on the left side where they had to sweep up to keep the cat in the stock location. Same with the AS&M CARB certified dual cat headers. Buddy of mine bought a used set for his 30th Anniv Z28, we installed heat shield materials everywhere we could, and they still melted the plastic parts of the dipsticks. He gave up on them. AS&M stopped making them.

mzgp5x

Yes they were the slp shorts for dual cats. Sorry I got it wrong... took out the plenum on the passenger side. Also, they always came loose. Looking back the Pacesetter LT's are a much better fit and exhaust solution. Live and learn. B.

cheapchevy

With the passenger side SLP header, one needs to attach some heat shield material against the plenum. See pic.

Only problem with my SLPs is that the header bolts loosen. To get to the passenger side bolts, I have to drop the exhaust pipe for access every few thousand miles. Perhaps better fasteners would help.

DrewHMS97SS

Is the need for the heat shield pretty standard with long tubes (mine are Jet Hot)? I just figured out an ignition fuse issue where the wires on the passenger side feeding the starter and crank position sensor were fried. As I have been digging in more, I also found that the plastic plug going to the passenger side wheel is melted really badly.

I was figuring the best thing to do was to pull the headers and install some DEI titanium header wrap on both sides.

I think I am going to make my life easier on the removal in reinstallation of the tubes by doing this at the same time as a tubular kmember. I am figuring that the headers will basically come straight down with the kmember off. Additionally I am hoping to have a bit more flexibility with the wires coming to the started with tubular kmember.

Thoughts?

Injuneer

If you have issues, put the heat shield on the wires, plastic parts, etc. Don't wrap the headers. I don't think that long tubes are any more problem heat wise than any others. The excessive heat problems discussed above were mainly related to the CARB certified dual-cat headers, that route the primaries up above the valve cover to keep the driver side cat in the stock location (required by CARB and Federal law). I like the Taylor Fire Sleeving.

The problem with wrapping headers in a street car is the fact that very little heat escapes, raising the tube metal temperatures to the point that mild steel corrodes as the glowing steel combines with oxygen (not due to the misperceptions that the wrap retains moisture). You start to get weld cracks from the heat cycling. Nasty.

Racers can use wrap to their benefit, keeping the heat in to promote increased scavenging, increasing HP. But they can afford to replace them every few years. Cera-metallic coatings, inside and outside the primaries is a much better solution.

The other problem is that oil can saturate the wrap, and eventually cause a fire. A prominent F-Body vendor, Tom Byrne, lost his Z28 due to an engine fire caused by oil soaked wrap. 15 years ago, but it's hard to forget.

DarkKnight

I agree with Injuneer. I posted this thread with a similar concern in addition to header type. I got my LPP long tube headers supposedly made from 321 stainless finally installed. I have to say, installation was not near as hard as I had read about. The only issues I had were to delete the factory oil cooler (which really helped my oil pressure as a bonus) and cut and trim some metal from the steering knuckle. No clearance issues on cross member or frame rails. To the point, I left the headers unwrapped based on this feedback. I wrapped all wires I could with DEI reflective wire wrap and heat reflective tape where I could maneuver wire wrap around. Unfortunately, I encountered the dreaded long tube Y-pipe issue of the fuel lines sitting on top on the pipe. I bent them up as much as I could, wrapped that area of the y with DEI titanium wrap and wrapped the lines with heat reflective wire wrap. Yes, I understand it won't eliminate the danger or possibility but it's been over a year now with no issues and and the wrap still looks new. As for heat, I have an SS ram air hood that is just vented and not used as a ram air intake which helps with cooling and heat venting. In my opinion the heat from the headers, even sitting at idle is not no where near as much as I thought it would be. Honestly, I don't notice much of a difference from the ceramic coated headers I had on before.

DrewHMS97SS

Thanks for this. I will hold off on wrap and try to use the DEI stuff to protect the cables. I took the fiberglass / metal sleeve from DEI, removed the stitching, then wrapped the wires. To keep the shielding on the cables, I wrapped the full length with DEI heat tape. How this routes under the header to the starter, what do you think about using a mounted shield on the header? https://www.designengineering.com//c...es-pipe-shield Or would re-routing the wires be smarter?