i am looking at running the LE 3 heads, port matched manifold and either the LE 2 or LE 3 cam, havent decided that yet, with stock bottom end and will be running 1 3/4 longtubes and was thinking about just letting the exhaust dump right after the headers, does anyone know if this will create a back pressure issue??? if so how much piping from the 3" collectors is neccessary on each side for enough back pressure??

 

1st get ear plugs, and 2nd expect to get pulled over for a noise violation if you drive that on the highway

 

There's some really good threads about this kind of stuff in the advanced tech section. If you're really set on dumping right after the headers, at least put some bullets on right after the collectors to make it a little quieter. It will cost you little, if any horsepower. And I suspect that even then it will be loud.

If you want some good insight into the whole backpressure myth you can read those threads in the advanced tech section, plus hotrod has some articles on their website. Some of it goes so far as to show that different lenghts of collector "resonate" at different rpms, which is quite noticeable on the dyno.

 

Install some purple hornie headers mufflers. They are Glasspacks that bolt directly onto the header collectors and have 3" turn downs on them. I'll sell you mine for $50 shipped lol. With this exhasut setup i noticed huge gains from my 2 1/2" flomaster true duals on my fully built 79 Z28.

 

naw, my buddy pretty much ran that setup with the header collector to header mufflers, it sounded good, but in my opinion i think it sounded ten times better once he took them off and just had open headers for a while. if anything i was just thinking running a little piping just past the header collectors for added back pressure if its neccessary for enough back pressure.... im just a little worried about cracking a exhaust valve after dropping $1850 for the heads and cam.

 

lol, i figure thats gonna happen every now and then, i'll prolly just take a picture of the exhuast before i take it off so any tickets i get around here for exhaust will get dropped.

 

IMO open headers didnt sound that good. The puple hornies sounded better but not much. You wont get much back pressure from an added pipe. You will also get knock retard. I had insane ammounts of knock retard. Anything over 2,000 rpm and the engine was flat. You should get a crossoever in there somewhere. The X pipe will add about 15rwtq or so. Atleast put mufflers on it. Open headers are the worst exhaust setup for power and sound. It will be unberably loud with the LE3 setup i can promise you that. You exhaust valves will only crack if the cold air gets inside of your headers and goes to you hot exhaust valves. This isnt too commong on longtube headers but can happen.

 

my friend had these short (like 8" long) glasspacks on his chevelle and it sounded really nice

 

i didnt realize that the x pipe added that much torque, i will definetly have to look into that, i dont really want to run mufflers tho, i like the loudness of open headers with a cam. how did you go about the piping when you got the x pipe? did you just order the mandrel bends online and have it all just welded together at a exhaust shop? i havent found any true duel exhuast kits for my car, and i can't seem to find anyplace around here with a mandrel pipe bender, and press bent piping is just ****....

 

What headers? The summit universal X pipe kit fits hookers and jet hots, but you will need to extend the pipe for pacesetters.

http://store.summitracing.com/partde...1&autoview=sku

 

15rwtq from a crossover? I would say maybe 2 or 3rwtq but are you sure of 15? if so then i might want to but an x on mine.

Dont run open headers, just put some bullets on you colletors and then some turn downs...thats what most drag cars do.


PS shawnmacanny nice exhaust it is simmilar to mine, those chambered mufflers sure sound nice dont they.

 

going with hookers so, not bad at all for 100 bucks, are u sure about the torque gains are that high tho, 15 rwtq?

 

* i just checked out your pics, how do you not scrape that exhaust over every little bump? thats crazy how close to the ground that is, i scrape at my test pipe all the time, shooting sparks on the highway over bumps, and my exhaust doesnt even hang anywhere near as low as that.

 

I scrape my exhaust alot. The roads in DE are the best i have ever driven on. I only scrape them going over intersections too fast, when things are in the road, or huge bumps. I cant go over speed bumps. I used that useless crossmemeber and longer bolts to hold up the X pipe to the frame of the car. It acts as sort of a skid plate so it doesnt hut my exhaust.

That is just an estimation. I think only one guy has ever tried it on the dyno and he got 15rwtq. Its the best type of crossover you can have and equalizing the side gives you the best back pressure. It also sounds mean as hell.

 

I drove about 20 miles with open headers after my rebuild. It was sooo loud my ears rang for the next 12 hours. It also ruined my o2 sensors and fouled my plugs. Not to mention it had 0 torque and ran terrible until I bolted a cat back to it. Good luck with whatever you do.