fesrone

I've been buying/piecing together my exhaust setup for my 88 NA. So far I have the RB streetable header and RB catback. Looking into finishing the setup with a Bonez highflow cat but was getting confused on how to keep my 6 port function working.

Will the

RB header + Bonez highflow + RB catback exhaust system

be a direct bolt on or will I have to modify/purchase extra parts to make the system work properly.

I apologize if this has been covered but I was unable to confirm it with my searches.

Thanks in advance.

Aaron Cake

iTrader: (1)

I suspect you will need to modify a bit to fit those parts together. Any exhaust shop can do the work though.

The Bonez cat has a port in the side to which the split air pipe connects, so it should open up the aux ports.

RotaryRocket88

iTrader: (7)

If the bonez cat is a direct replacement for the stock main cat, there will be a 3" gap between it and the header. Everything RB makes is intended for use with their presilencers, which are not the same length as the stock main cat.

fesrone

Ok, thanks for the replies. It sounds like buying the presilencer and keeping my stock exhaust setup would be the best way to go for next years emissions test. I assume the RB presilencers will fit S5 and S4 models? I will call RB to confirm but would like to check rx7club first for some insite. There's some used presilencers on craigslist for around 100 bucks that look promising.

3vil

iTrader: (4)

doesn't the RB header have the pickup off it to actuate the ports?

RotaryRocket88

iTrader: (7)

The split air pipe / aux. port hookup is on the presilencer. I have seen a header with a pick up tube, but I think it was custom.

fesrone

I called RP and RB and was told some conflicting info that hopefully can be cleared up. A rep at RP said that the header I have part 16130 is the same header they use for their RB header/Bonez cat setup and there was only a hookup for the air pump used to catalyze the exhaust air to pass emissions. Then I asked about my 6 port functionality and the rep mentioned that S4's 6 port actuators run off of exhaust pressure and the pickup tube available on one model part number 16128 RB header was not necessary for my car.

The second call to RB the rep told me that in order to keep 6 port actuators working with my header I would need the part number 16405 RB presilencer which has the pick up tube built in.

So my question is...can the S4 6 port actuator system work on just back pressure or is some kind of pickup tube necessary. I want to pick up the Bonez cat and keep emission legal but wouldn't mind presilencer to keep my 6 port working (which is what I want to preserve).

Sorry for the story but just wanted to give you guys some insight from where my head is at right now.

Thanks again.

RotaryRocket88

iTrader: (7)

A pick-up tube is a pressure source. You just need a tube coming off some piece of the exhaust, and hopefully enough restriction (from a catalytic converter element usually) to produce about 2-3 psi of backpressure in the tube.

From the description you got from the Rotary Performance rep, and the image on their site ( http://rx7.com/store/rx7/fcexhaust.html), it looks like the RB header + Bonez cat will bolt up just fine. It looks like the entrance to the main cat has been extended to meet the header.