V6 Headers

My Hedman fenderwell headers have reached the end. Actually they where there quite a while ago. Between the last three trips I've had to remove them to weld up leaks. Repairs upon repairs. Holes and rust. Last weekend I did this trail repair as I detest the sound of exhaust leaks.



I really don't want to deal with new headers now as there are other priorities with the jeep. Although the Hedman fenderwell headers are fairly inexpensive I had planned to get away from them so I can route the exhaust inside the frame rails over top of the cross-member so they are protected. The fenderwells give it an old school appearance that keeps me well clear of rocks. Surprised I haven't ripped them out! As you can see from the picture they are out there.



So I've pretty much decided to go ahead and get some block huggers. I'd sure like some qualified opinions on fitment and exhaust routing. Having done the searches I believe I would go with the Novak block huggers. I understand that Warlock has helped Novak make some improvements. I could move my saggy shaft if needed. Is there sufficient clearance at the front driveshaft? Anybody have any pictures?

I intend to fit and weld all the piping myself. I have no problem there.

I'd like to keep dual exhaust with a crossover. But if I'm going over the crossmember on the driver side of the t-case I imagine it would be singled at that point. If so I may just re-use one of the Dyno-Max mufflers and tuck it up under the tub just forward of the axle. There's an air tank behind the next to last crossmember so it can't go there. Tell me what you think.

 

Go with single exhaust and manifolds. That way you can keep everything under the frame and not rip off the mufflers. Ask me how I know.

 

Chuck

So what did you do to get around the Saginaw steering shaft?

 

Getting around the steering shaft obviously depends on your own setup but is easily done. I have an original column that I modified to work.



I used a couple of narrow U mandrel bend 2", 2 120* bend sections, and straight pipe to weld mine up. I cut up sections of the U bends to make the necessary turns. It leaves the headers with the 120s up and over the x-member then crosses over from the passenger side to a series 50 Flowmaster (dual 2 1/2" inlet to single 3" outlet). I sized down to a 2 1/2" single outlet at the driver's rear corner. Flows great, sounds great, and the only exhaust visible below the frame rails is the 120s coming off the collectors. Haven't had it in the rocks yet but nothing has touched it, not even gravel dings.

 

Granny,

Thanks for the pictures........I have a set of fenderwell pipes now and I just finished some rock guards that are frame mounted on both sides. I can still use that style fenderwell pipe but would have to shorten up where the collector ends and then still drop an exit pipe under the frame rail to get them out the back. I Like the Idea of the block huggers but my drivers side is very conjested not only with the steering shaft but years ago I built a kick-out pan that adds a quart and a half to the system. I'm not against building a set if it comes to that.
Question: Those pipes are obviously short to the collector which tells me they would not have much low end torque............do you notice that?

 

I haven't really had it out grunting around yet so I haven't noticed any torque differences. During average driving the run up is so much quicker I've had a few squirrelly corners on dirt roads. IMO these are akin to really efficient manifolds.

 

Chuck / Granny...........Normally a short pipe to the collector is more apt to work better at higher RPM's whereby a longer pipe to the collector creates a little more back pressure and therefore some additional torque at lower RPM?

Question: Are you both using the 50 lb flywheel on the V-6? I'm thinking about putting the 30 lb back in there...........Why you ask? I now have a T-18 w/ 6:32 gears in the low hole. I do not see why you need the static weight generated torque created by the heavy flywheel when you have the ability to have the same whereby generated by the compound mechanical gear ratio.................Thoughts?

 

X2 on the headers. High HP headers have long individual primaries. Torque tubes either have short primaries to collector or short primaries split up into two intermediates that then go into collector.

Have never swapped a flywheel so have no input on that.

 

The heavier mass of the flywheel is a definite advantage if running rocks or in need of slow speed torque. Lower gearing is an advantage most definitely, but will not keep the engine turning over under heavy load like the inertia of the heavy flywheel. I have the light car flywheel on my 231 in the '59-5. I like it in mud, sand, and street as it allows quicker rpm acceleration. On rocks or heavy, rough, and steep climbs many times I've wished I had the heavier flywheel to help keep the engine turning over.


Sent from my iPhone

 

Guys.........I'm not so sure I agree on the long versus the short pipe theory............ But I would agree that pipe length in a lot of cases becomes car ,engine,RPM and application specific.
I have reprinted this basic header info below off a manufactures website..........


Here is a reprint available on the Internet.............Exhaust system tuning:

Many headers are also resonance or length tuned. Typically, longer primary tubes resonate at a lower engine speeds than shorter primary tubes. This means that shorter headers produce more top-end horsepower while longer tubes produce increased low-end torque gains. This type of tuning utilizes the low-pressure pulse which can help scavenging the combustion chamber during valve opening overlap. This pulse is created in all exhaust systems each time a change in air density occurs, such as when exhaust merges into the collector. By tuning the length of the primary tubes, the low pressure pulse can be timed to coincide with the exact moment valve overlap occurs.

Many automotive companies offer aftermarket exhaust system upgrades as a subcategory of engine tuning. These upgrades can significantly improve engine performance and do this through means of two main principles:
•By reducing the exhaust pressure, engine power is increased.
•By reducing the amount of heat from the exhaust being lost into the under hood area. This reduces the under hood temperature and consequently lowers the intake manifold temperature, increasing power. This also has positive side effect of preventing heat-sensitive components from being damaged. Furthermore, keeping the heat in the exhaust gases speeds these up, therefore reducing back pressure as well.

Tuning the pipe:

Because a tuned pipe cannot be effective over the full spectrum of the RPM, it has to be "tuned" for a certain RPM range. Usually, high performance headers are tuned for the lower RPM because that's where most engines have weakest horse power and torque. By adjusting the exhaust pipe's total length the engine can be "tuned” at the pipe. During a testing or development phase most tuned headers are cut at the coupler that connects exhaust manifold and tuned pipe little by little and test driven until improvements are seen at desirable RPM band. Generally longer pipe moves the effective band of tuned pipe to lower RPM range, and shorter length moves the effectiveness band to higher RPM.

Definitions and Terminology:

Terminology:
•4-2-1 Headers or Tri-Y’s - On V-8 engines where 4 pipes merge into 2 then merge into 1. Different opinions as to which cylinders in the firing order are paired to provide desired performance. In a V8 the pairing tends to join cylinders with similar firing intervals, and this will differ between left and right cylinder banks.
•4 into 1 Headers - 4 pipes merge directly into 1
•Shorty Headers - This is basically an exhaust manifold that is fabricated from tubes instead of stamped or cast iron.
•Equal Length Headers - Each downpipe is the same length from the exhaust port to the collector cup. These are usually used when the cat-back exhaust system is resonance tuned.
•Zoomie Headers - Built without a collector for supercharged and racing applications

 

Hmmmm. Yea, I always thought that longer headers made more torque.

 

Hey guys, thanks for the pictures. That really helps. I'll get under there this weekend and eyeball the routing.