Headers suck! No heat riser or hot air tube...

[eagle mark]

The headers were on my 90 blazer when I got it. First thing I noticed was the oil filter was hitting one tube, so I took it off and dented the tube. They leak, they rust. You loose your heat riser and hot air tube which really helps in winter driving up here.

Are they really worth it? Power and MPG? I'm thinking of a stock exhaust system... A freind has a set of headman elite coated which I could get a good deal on but the part number 69238 does not show up on the headman site...

 

[Texas Jimmy]

heat riser kit is about $10. I've had mine so long I forgot where I got it. Thinkin' it was napa. My coated Flowtechs are 12 years old, copper gaskets, no leaks, and no probs. No rust in Texas. 89 Jimmy. In a "sniffer" county.

 

[ryoken]

you get what you pay for...

 

[dyeager535]

Completely worth it. "Impartial" dyno tests on stock motors (I've seen them for 5L Fords and 5.7L Chevs) consistently show an increase of 40ft lbs of torque, and the one HP test I saw for the 5L Ford was close to +40HP as well.

 

[454k30]

I have to agree with ryoken; with headers you get exactly what you pay for. Cheap/bargain = Rusty, poor fitting, leaking junk. My advice to people is if you can't or don't want to afford the good ones don't buy them at all.

 

[eagle mark]

Completely worth it. "Impartial" dyno tests on stock motors (I've seen them for 5L Fords and 5.7L Chevs) consistently show an increase of 40ft lbs of torque, and the one HP test I saw for the 5L Ford was close to +40HP as well.

Those are good improvements. But if it's all above 3000 rpm I will probably never use it... is there any MPG gains?

 

[4X4HIGH]

Power is made in the cam, heads, intake and exhaust system. There is a big improvement with just headers alone even at low RPM's. Combine all of the above in a package that is intended to work together and you'll make the most improvement.

 

[dyeager535]

is there any MPG gains?

I don't know as there can be...better exhaust flow means better intake flow (allowing that the heads are being restricted by the exhaust). Better flow means more fuel necessary keep the mixture optimal, which means more gas.

I believe the accurate way to test fuel economy from a motor is brake specific fuel consumption or some such, not sure I've ever seen that tested when engine modifications are done, such as the way they dyno test most magazine builds.

Talking solely about the engine, reduced friction, less reciprocating weight, combustion efficiency etc. all should increase MPG, but power "improvements" are probably a wash...gears govern engine RPM, and displacement/engine RPM are "fixed" values that greatly affect fuel consumption, I don't think you can reduce fuel consumption except by the above, or changing displacement, reducing engine RPM (up to a point), or running the cruise mixture lean. This is why new trucks show relatively little improvement over fuel economy of trucks 20 years older.

 

[BGKYK5]

You should see a small improvement in mileage from headers because of the reduction in pumping losses. The engine doesn't have to use as much power to pump out the exhaust gases. However, pumping losses are pretty small compared to all of the other losses (friction, thermal, etc.) inherent in engines.

 

[rcamacho]

Hot air is an easy retrofit with a kit or tack welding on a tube with enough air clearance to flow - i.e gap around 1/4 or so of the fit. Heat riser valves are also available if you know your collector diameter. Most of the header mfg can match a valve to the collector size.