How much HP will I lose switching from Apexi Duel N1's to RB duel tip?

 

1 or 2..... they all give the same amount of hp, it all depends on what sound you like.

you wont notice it unless you dyno it before and after.

 

Thats it? Hell I was worried it would be like 15 to 30.

 

none

 

nothing to lose sleep over. i wished it was 15 to 30, since i have the n1s. hahaha.

 

i gain probably 15-20hp switching from RB to N1 dual with both silencers off.

 

rwhp? wow, that is a lot. maybe it is enough to lose sleep over??

 

Yeah, I could tell the difference when I put the silencers on my Duel N1's last week. I know I lost power, but who knows how much without a dyno.

 

Why are you switching?

 

running the n1 duals with silencers is noticible to the point where i would not race with them in. it is a big difference. they just dont flow with the silencers in.


the rb catback is more restrictive. i was just having that conversation with bryan from bnr about that catback and he said he gained about fifteen hp by going with his new setup over the rb at high boost.

j

 

I'll be dynoing atleast 3 cat-backs in June. I've got the PFS cat-back on the car now and made 363 rwhp. I've got the Blitz nur spec and greddy titanium cat-back (with and without the silencer) as well. I'll dyno them and see how they compare. Might be able to get the N1 duals as well. Weigh them and take some pics of them on the car. If I can find a decibel meter I'll do that as well.

Tim

 

To keep a cop of my back.

 

I wonder exactly how much HP is lost with the silencers in? Has anyone tried this on a dyno?

Artguy, have you read any C.S. Lewis books lately?

 

15-30 HP? Are you kidding?

 

No

 

If it is only 15 HP I can live with that. I just don't want to drop below the 400 HP @ 1BAR.

 

Well since the exhaust won't even give you that much power then I would think that you wouldn't lose that much.

 

How did you test this? By your butt dyno? If so that is very inaccurate. If on a real dyno I would love to see the charts for comparison.

If anybody thimks the RB is too restrictive, I would again love to see the flow chart for the claims. RB has done plenty of research on their exhusts. There are a few people running it with their 20B conversions. And that is what is going on my car next.( If I can live with that god awfully ugly bracket on the back side of the can. UGLY) I have the GT on now and it is way loud.I am also single turbo FWIW.

 

Thanks for putting up the bullshit flag on this one.

The RB Dual tip, is a straight thru design. It will flow on par with any other straight thru design. Subjectively I can say that the N1 duals are 2 straight pipes so that may account for a little less restriction, but I seriously doubt it is much.

Noise does not = horsepower. The difference with the RB duals is the amount, and type, of packing they use to muffle sound. They must have 10LBS of packing in that muffler. This is what keeps it quiet, while not giving up any horsepower.

Take a look at you N1's. My guess is that the packing that is used is minimal at best. The only way to quiet it down from this point, is to add restrictive silencers, which changes the design to less than ideal, or straight thru.

I switched from a fart can rice design to the RB duals and resonated MP. I was able to lower the sound by 30db. It would even be considered legal, if the rest of my car wasn't a walking ticket.

 

The Duel N1 silencers are a joke. @ Idle the car sounds about the same. And then it just sounds really funny and only a little quieter over 2000 RPM.

Jesuscookies, which resonated MP did you go with? On a scale of 1 to 10 how much louder would you say your car is over stock?

 

yea...butt dyno....!!! that is where the BS stop!

I measure is with autocross time, we had autocross two days back to back, Saturday with RB and Sunday with N1. Different course, different place, same enemy and they are consistent, we are gaining time on them.
Of course there might be other factor too, such as the weight reduction from RB to N1. probably 10-15 pounds.

With N1 Duals open, the low end suffers though....
The RB gives good low end, similar to running N1 duals with silencers.
The perfect balance is N1 with 1 silencers.
but on track/open course, you better of with open N1 Duals.

Oh yea, for the record, I have downpipe, highflow cat. Thus the RB is the most restrictive part of my exhaust system.
I am sure it is different when someone still have main cat, or plus the pre-cat. With main cat, the N1 is just a fart can. A forum member here bought the RB and I helped him install, at that point I realized that the main cat pipe diameter is really small compare to my hf cat.

 

All the information you put in this post is speculative at best. This is the equivilent of forum gobblygoop.

If you have a high flow cat. Then that will be the most restrictive part of you exhaust. Not the racing beat catback. If you have a chance, take a look at what a cat is, and how it is made. That should shed some light on the situation.

 

Brady,

here is the information for my catback install.

https://www.rx7club.com/showthread.p...t=catback+94db

As a general rule You will lose 15 to 20RWHP peak horsepower by going with a hiflow cat. (from a straight pipe ) However, this number is a bit deceiving, as you really are changing the way your powerband is behaving.

There is someone on this board ( I can't remember who) that has a web page showing both a hiflow cat and a straight midpipe. Below 4000RPM the Hiflow cat allowed for the most power. But at above 6000RPM the hiflow cat choked it, and the car favored a staight pipe. Indicating again that you are losing horsepower only peak operating RPM

Hope that helps.

 

This comparison is very inaccurate. You said yourself it was a different course ,different place. Those 2 differences throw your data out the window. And you are the biggest factor in the altering times of your runs, NOT the exhaust. Sorry to break that to you.

And next time you have the RB around you look thru the damn thing. It is as straight thru as the N1. It just has more packing to keep it quiter. As Jesuscookies stated already. And also as he stated if you have a cat of ANY kind on the system, That is the most restrictive part, again, NOT the RB exhaust.

 

if you haven't had a dual n1 please don't make assumptions

I bet you lose 35rwhp putting in the silencers in the dual n1

the rb is WAY more restrictive than the n1 its a quiet exhaust but a POS for flow...the dual n1 is just the opposite. Most other exhaust are somewhere in the middle of these 2 with single tips flowing slightly more than the dual n1.