Before any of you gets mad for creating another thread, haha.. I did use search and read relating threads.. but I just was curious since those threads has anyone put them on there blazer and if so, tell me about what you noticed.. if you know people that have, great - please tell!
Im exploring my options as far as 350 swap goes, and so far its looking like a big penny.. so im checking out other avenues and im just curious how much of a difference these JBA headers will make on my current 4.3L engine. What will it exactly improve? Besides what it says in the description - because half the time its all garbage. Will it make sound any different? Worth the buy? With these headers and a K&N FIPK installed get me any faster? How much etc and so on. Thanks guys, appreciate it.

http://www.car-stuff.com/performance...p;skipped=true

What is air injection by the way? If someone can give me a explanation; that would be great!

 

your link only tells us that there is free shipping lol. Also air injection is something that they did to the blazers (emissions related I believe) as far as I know every blazer has it that is within our year range. There was a post about how to find your air injection around here somewhere if you search "air injection" you should find it.

 

Air injection is an emissions related system. Well, sort of. From what I've been able to determine, it's function was to extend the life of the catalytic converter, but I have read many success stories of people that have removed theirs and had their PCM modified to suit. These trucks were still able to pass the tail pipe emissions test with flying colors afterwords. Although, it is possible that if the inspector knows what they are doing that they could know that you have removed the air pump, etc.

Here is the JBA Application Chart.

 

Air injection has been used on Chevy engines since 1968 and injects by way of a pump. It affects the exhaust gas emission values. First came AIR injection, then EGR valves, then catalytic converters. Actually PCV valves came first.

Removing the air injection TODAY requires reprograming the computer, anyone thinking of doing this should look inside the holes in the exhaust manifolds to see just what is in there, in the old days there was a tube with holes in it still hole which blocked the exhaust manifold (we put them in at the factory when we built the engine, the tubes were put on at the assembly plant). When ever I saw someone with plugs in the holes I'd ask them if they popped out the fitting. 9 time out of 10 they didn't. I don't know how they do it today or recently.

*combining consecutive posts*

Oh, the headers. The headers can't do anything but help, but you need to do a LOT more than just headers. Put them on, then make up a Y pipe if you plan to run the exhaust out the back on a two wheel drive, otherwise you'll have to go with side exits (in front of the wheels).
1) Out the back. After you devise a Y pipe run it into a 3" free flowing cat, then into your favorite hi performance muffler, then fabricate the rest of the exhaust out of 3" mandrel pipe (most muffler shops can't bend 3" pipe).
2) Out the side, if your state requires the cats be in place pick up two of them (you can use the cheap ones, your only flowing 130 cubic inches). Then again into your favorite mufflers. You only need 2 and a 1/2 inch because of the lower flow. If you want to get fancy, and have the room put a X pipe on it. But this way it will look like s*** because you have to bend the pipes to fit under the frame. Stand back 10 feet and look, even on a 2 WD you'll see the frame, the body is mounted higher.

PS: May I suggest?. For the cost you'd be better off fabricating a new exhaust starting at the end of the Y pipe. Put on a free flow3 inch cat, then a 3" in and out muffler, the a 3" mandrel tail pipe. This will cost about a $100 for the cat, anywhere from $50 up for the muffler, another $50 or so for the 3" pipe and mandrel bends then whatever the muffler shop charges to put it all together. In other words that system will cost about what just the headers cost.


*EDIT: swartlkk* - Combining consecutive posts. Please use the Edit function to add any additional information to your post if another member has yet to reply.

 

3" exhaust on a 4.3L is overkill to the side of being less efficient than a more appropriately sized 2-1/2 for a single exhaust with everything else being stock. Free up the intake and cam it and 2-3/4 to 3" depending on the properties of the cam may be best.

If you go too large, you have a problem of exhaust gases expanding, causing the flow to slow down. By finding the optimum exhaust size, you will keep the exhaust velocity high.

 

Swartz: The 4.3 is half of a 8.6 V8. Or for you, a 262 is half of a 524. Now if you had a 524 cubic inch V8 how big an exhaust would YOU run?. Or, if you had a 283 V8 would you run duel exhausts?. 2"?. How about this. Do you know how to find the area of a circle?. That's Pi times the diameter.

Add to that the fact your dumping thru your Y pipe into first a cat and then a muffler. Assuming you have a Blazer made after 1996 and/or live in a state that requires cats to be in place to pass inspection. BTW, in New York the inspection requires a 1996 and later car or truck with OBDII to be plugged into a phone line which goes to the DMV in Albany. But maybe your inspection station will give you a sticker without doing that. Hey, it's THEIR license that will get pulled if caught, and they'llpay the fine. My station will do a "visual" on a pre 96 but says I MUST plug in for my 96 and later cars/trucks.

A 3"SINGLE exhaust is not to big. You SHOULD have nailed me on the duels. In the case of a duel exhaust a 2" pipe, or 2 and a 1/4 is plenty.In that case your dumping 1/2 of a262 or 131 CID, not 1/2 of a 524 CID V8.

 

That just confused the hell out of me, lol.

 

I'll make it simple for you. The question was on headers. I said if you put them on and went with a single exhaust pipe to exit all the way to the rear you would have to fabricate a Y pipe, feed that into a 3" in/out Cat, then to a 3" in out muffler, then fabricate a tail pipe out of mandrel bent tubing (Because most muffler shops can't bend 3")

Swarts said 3" was overkill, too large, not needed. I asked him what size he would recommend for a 524 CID big block?. A 4.3 is 1/2 a 8.6 V8, or 1/2 of a 524 V8 if you don't understand that. A set of headers running to a single exhaust should have a 3" system.

Stock is 2 and a 1/4, I put on a Flowmaster and 2 and a 1/2 because my muffler guy can't bend 3 (stock manifolds). Do whateever you want, but be aware your exhaust is the same as 1/2 a 8.6 liter V8.

 

Never heard of anyone having to plug in there obdII into a phone line. I don't even think I have seen a OBDII reader that has a phoneline connection on it. But I also don't live in NY, but do live just south of NY. And know allot of ppl where I work that live in NY. With exhaust all I know is you don't want to open it up to much and you don't want to make it to small. Cause if you cut off to much back pressure you will mess up your motor. But if you make it to small it will choke itself because it can't get the exhaust exited fast enough. Assuming my priniple though is correct. But assuming is a big leap. Cause you know what it can lead to making an **** out of U and Me. That is why when I plan on doing my exhaust I'm going with 2 1/2. Of course I have no real mods done currently. But plan on getting headers, HI flow cat that is OBDII compatable, and performance muffler. Just my 2 cents

 

Read my post again, I said WITH HEADERS!. I assumed that anyone who would go to the time and trouble to put them on would do more than just a air intake. I also said that I used 2 and a 1/2 on my mild one. But if I wasn't cheap I'd put on a 3" cat and 3" on back.

You evidently can't wrap your mind around the fact your exhausting a 262 cubic inch engine and 3" isn't to big as a SINGLE exhaust.

You've evidently have never looked under your dash and seen where you plug a reader into your ADAL (?) to bring up trouble codes. All cars have one. Since the 80's. Ask your mechanic. In New York State the inspection station is REQUIRED to plug a connector that goes to a phone into it. It then goes directly to the DMV. It reads what the computer is saying. This test is required on ALL 1996 and later cars in trucks.