greaseman

Relisys190

iTrader: (4)

Racing beat makes a great product. I am running the road race true dual system on my s5 N/A car and had fantastic results when I went from stock OEM to full SS header/pre silence/twin mufflers. I did not dyno the car but there was certainly an increase in performance. The system is designed to work for a stock port engine. Some restriction is a good thing and for your situation you'll need back=pressure to operate your aux ports at higher RPM. On a previous N/A car I ran Racing beats header assembly and no center section silencer which split into a Y pipe to Borla mufflers. It was really way too loud for street use.. I'll gladly stick to the RB roadrace true dual setup until I make major internal changes to my engine which may be a long time from now since I drive it 2 days a week.

Good luck!
-M

greaseman

dguy

iTrader: (8)

We stopped using 'true dual' and the awful 6 bolt flanges in our E-prod cars years ago. We realized zero benefit in both weight and flow compared to a properly collected header to a single passenger side outlet. Also don't try to play with ovular piping if you're trying to get froggy. Exhaust resonance tends to blow it up over time.

greaseman

dguy

iTrader: (8)

For a street car just use the RB collected header and have a single exit made up. It will be annoyingly loud but hey, it's an NA.

bilcoh

Had the same question. Thanks guys.

damienslc

Rotary engines require back pressure to operate seeing as how they don't have the "plunger" effect of a piston engine, unless you have a peripheral port engine. A straight through exhaust will only only hurt your performance. On a N/A rotary engine, the factory spec for exhaust is ideal if you plan on keeping the factory fuel injection system. Unfortunately, the N/A rotary is pretty much maxed out in its current design.

scathcart

Dak

This is incorrect. The better flowing the exhaust is the better it is even for stock ports. Once an engine is ported the need for a free flowing exhaust is even more important. A straight thru exhaust is exactly what you want but with the right pipe diameter. Ditching the factory n/a exhaust is the best thing you can do for power if the right diameter piping is used. I think that is where the notion that a rotary needs back pressure comes from. People " straight pipe" one using to large of pipe and it causes the velocity of the exhaust to slow down too much and hurts power.
https://www.rx7club.com/naturally-as...1/#post8663850
https://www.rx7club.com/naturally-as...0/#post8426237

Gabriel82

iTrader: (8)

Here is a link for the S4 RB Road Race Exhaust

I'm running a complete S5 Racing Beat Road Race Exhaust. Great throttle response and the car is not loud what so ever. No nonsense with mounting, it bolts up correctly because it's made for our vehicles. Combined with my street port engine, vdi mod, and pineapple 6 port inserts i'm putting down 165whp. I'm still using the stock ECU and injectors.

S5 NA Streetport Build

SloMO

greaseman

Okay, I've had the RB true duals for about a month now and I love it. Thanks for the help guys. I'll probably get the mufflers eventually.

DaBrkddy

I've had the Racing Beat "Road Race" true duals on my car for a few years, and this is one of the best systems money can buy. The car makes more torque across the usable range, and more horsepower on the top end. Mine has a really agressive exhaust note because I used 2 1/2" magnaflows behind the RB presilencer. Compared to stock, the engine wakes up very noticeably around 1,700 RPM and pulls hard to redline.

I've raced guys who have a Racing Beat single exhaust and they just don't pull as hard. Long primary systems are perfect for these engines in most applications, and Racing Beat knows that- that's why they made this system, and that's why it's not cheap.

its66

iTrader: (2)

With Stockports, 89+ engine and intake, I've made 173+ on 4th gear pulls with a 5.12 diff. peak power was near 7000-7200 rpm IIRC. That was with RTek ECU. I don't think anybody builds that exhaust anymore, except maybe Steve Eckerich. With ceramic seals and more computer control, I bet you could see over 180 with stock ports. There is a LOT to properly designing an exhaust for an NA rotary car.

djessence

I assume it has an O2 sensor bung? Where is it on the header and is it on an oncollected pipe? (IE which rotor and how far down is it)? Trying to get something similar up in an S5 Motor in 1st Gen Car.

Dak

Yes. On the uncollected it is on the rear rotor. I can only go by pictures but doesn't look to be too far back. On the collected it is just after the collector.

Dak

From what I understand the RB collected system though good is somewhat of a compromise as it's better than stock but not as good as a properly tuned system. The primaries are too long for a "short" primary system and too short for a "long" primary system. Hence why yours pulls better than their off the shelf single/collected system. I'd really like to build a system that collects as close to the diff as possible to still be able to split to keep the dual muffler setup. Something like the Defined Autoworks header but with a pre-silencer in it.

Relisys190

iTrader: (4)

Dak

You're right. Somehow I thought it was on the rear. Must've looked at the picture wrong.

djSL

iTrader: (5)

FWIW, I've actually dyno'd my s4 NA with two separate exhausts on the same day with no changes in between. While I was stock port (albeit, with itb's) at the time, the true dual made less power and torque than a collected exhaust that I borrowed for testing. Now that I'm peripheral port, the true dual is really holding me back in terms of the power I could have (currently at 253whp, can be higher).

Overall, the road race system is good but not ideal, especially considering you can have a custom stainless exhaust built to your specs for 300-700. In addition, I'm not a fan of the added weight you gain for less power.

If you'd like more info on my dyno tests, I have a thread in the dyno graph/time slip area of the naturally aspirated section. Cheers.