I need some help here... I called a Mazda specific shop in toronto because they are a racing beat distributor. I was looking at the full RB engine back true dual setup for my currently stock 87 NA (street-port in the spring.) But, the muffler guy just tore up that idea, and said it would be garbage unless i was running a full peripheral port full race setup. He promoted his own custom exhaust. header collecting into a 2.5" single pipe with pre-silencer, and then a split into duals after the axle. His reasoning is that the true duals have no low end torque, its all high rpm, and his is a good all around gain, more low end torque, and even more hp than the dual on a stock engine. For all stainless he wants $1500 can ($12-1300usd) for everything.
I dont trust him... is he right, should I trust him?

 

I think he is right, to a point. The true duals do have some low end torque, its not as bad as it sounds. In most cases, a collecting header is actually better! This was explained a little while back wonderfully by rotarygod. Theres a a lot more engineering involved to an exhaust system than just running pipes off the block.
Search for rotarygod and look under posts that are titled with exhaust, you'll find it.

 

I believe the true dual exhaust actually robs performance on the stock or street ported setup. Call Racing Beat though.

Their website has different exhaust based on stock vs street ported vs full-on racing.

 

On another note, a member here bought some true duals for his n/a and really didn't see much of a gain, but he also wasn't sure if his port activation was kicking in...

All im saying is that for a grand US its hard to justify.

 

Getting a Streetport on an N/a isn't really worth the money. You also won't get huge gains off the exhaust.

 

Going from a stock exhaust the gains will be HUGE. BUT, the gains would also be huge with a normal header and catback system.

So, the True duels are not going to give you huge gains over a system that costs half as much.

 

Just order the hole Racing beat system, single to duel, it's much cheaper than his and has been tuned. So, you know that itll work.


Gil

 

i beg to differ.
im tired of all this anti N/A stuff.. if you have a NA, and you like your car, put work into it, and make it the best you can. Porting will improve any rotary.

with the exhaust - do you meen like huge gains like... as soon as you do full exhast your gonna feel like your in a airplane taking off... well, no.. bu you will see a difference.. i know cause i did it.


just my two cents

 

even just gutting the cats on an N/A makes a very noticable difference...