Ok, I am looking for answers were there should be some. How much power is being robbed by having a short length header compared to a long tube header such as Mazdatrix's long tube '79-85 system with a Bridgeport? I asked this before, but apperrently no one here has a long tube header.

I am going to cut my header right before it collects and wield in pipes back to the muffler flange before the axle and have it collect there. This should give the same effect as the Mazdatrix item for a fraction of the cost if I bring it to someone I have worked with before. I am aware of the pre-siliencers they have on the Mazdatrix item, but I'm not worried about noise, my muffler is basically a shell now as its had many backfires through it over the years and I can easily live with its noise level.

But I really want to know how much effect this should get because a bridgeport needs high flow, well tuned lenghed, and correct diameter piping.

ANyone?

 

I've only seen one bridgey live in person, and its exhaust system consisted of a RB Road Race (dual exit) header. That's it.

 

I've seen several road race only bridgeports collect right before the axel. They made very good power. I really couldn't tell you how much power would be lost collecting there vs. collecting right before the muffler. Exhaust tuning is a black art. Check the Racing Beat catalog for reccomended exhaust lengts and get out the tape measure.

If you're really concerned about exhaust flow and getting a lot of hp, instead of hacking up the funny bent RB header buy the uncollected stainless steel race header from ISC Racing. $300. They build Rx7 race cars. (863)324-2742. Talk to Mike.

Use 2" O.D. 1 7/8 I.D. tubing.

As for short header vs. long header, I had the Mazdatrix (RB) short system and it made less power thru a narrower powerband at a higher rpm than the long system. Long system made more noise, but with the dual presilencer setup it sounded real goooooooood.

As for not worrying about noise, Jesse Ventura must have abolished auto noise laws if you're going to be running around in a 110db car with no workable mufflers. Wear ear plugs. And ear muffs. Seriously.

BradP

 

Well I am pretty sure my short header is not what the bridgeport needs as it seems to level off powerwise too early in the rpm range...partially due to improper jetting since I am waiting on jets.

SO Peejay, the guy your talking about had full uncollected dual piping to the stock muffler location? You didn't get a ride by chance? And how loud was it? Did he have somekind of muffler for each pipe back there or something?

 

Brad, I live in the rural minnesota 50miles from the St. Paul. No one cares about noise here. Except when you drive through a retirement comunity where they choose to use hearing aids. I hear big 4x4 trucks go by my house daily emitting more noise then I do with a bridgeport with current exhuast! I live near a place that sees many harleys go for moding there engines/body panels, etc. So no, noise is not a concern as long as I have mild muffling going on for my own benifit.

 

Read it again. He had the header. That's it. No mufflers, no pipes.

From about 20 yards away it was painfully loud when he launched. It was the first time in my life that I had a "pain" reaction to sound. (My daily driver used to be a 429 running open headers, and last year I drag-raced a streetport with open headers)