kettlman

iTrader: (2)

ok. i've searched, yet didn't find what i'm lookin for.
plain simple.
What muffler will give me the best performance and decent sound. this is for a 12a stage 2 ported on primaries, stage 3 ported on seconds, racing beat headers rb all the way back, holley 600. will those straight through mufflers be the best performance, or the rb one i already have?



late

vipernicus42

iTrader: (4)

I guess you didn't search very far!

On this forum, the general consensus regarding exhaust is that you cannot get any better than RB. Alot of aftermarket mufflers will get eaten right through by the extra-hot heat of rotary exhaust, making it hard to find good quality, high-flowing mufflers.

RB has definitely done their homework when it comes to their exhaust, and they're the only brand you should really look at when considering exhaust upgrades. A Racing Beat "Street Port" system is the best system for ported engines. It has the nicest sound, and by far the *best* performance numbers out there. Dual header back to dual presilencers, collecting just before the powerpulse muffler. If you're runnign the single-tube system from the header back, then you could be doing better, but it still isn't bad.

Stick with RB, I don't think anyone else here will tell you any different.

Jon

O 16581 72452 5

Mindtrain offers an exhaust system for Rx-7s as well, go to www.kickyride.com and e-mail them for information.

fatboy7

Just as far a mufflers go, I'm sure that you might pick up a pony or two by going to a strait through, instead of the RB power pulse mufflers. The sound level on the other hand would go up disproportionately. Just make sure the muffler is stainless, and stainless packed.

Sk8r_dude

depend what you want. if you want close to stock sound lewvels, go with rb. if you want an F1 car noise level go with reactive, sebring, vibrant or something similar.

kettlman

iTrader: (2)

i don't care all that much about the noise.if its load it will give the honda's something else to be jealous about. i just want performance.


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813KR$

If you want straight performance only, DONT get a RB muffler! I have run with and with out. With out runs MUCH better! I ran 10 secs in the 1/8 mile, then ran headers only and instantly got 9.6 while spinning the skinny tire off the line and through second! Response and power was increased!

dvcn

I have run Racing Beat mufflers and exhausts for the past 15 years. My 85 GSL-SE has the street port exhaust on it. Last wednesday night I ran a 13.85@99mph. It has a street port 13B with RB Holley setup. It is not fully tuned yet.

My previous setup had an 86 6pt 13B, non-ported. With the RB Dellorto and RB street port exhaust I ran a 13.96@97mph.

I'll provide time slips if anyone is interested. BTW my 1/8th mile times were in the 8.9's.

Bottom line: The Racing Beat Primaflow muffler does not kill power on a street/strip car. It will last forever and keep noise at a legal level.

813KR$

Next time run straight headers and you will be suprised how much the Racing Beat muffler holds your engine back ! ! !

CODE BLUE 2

Do RB....

dvcn

813KR$-
I've read some of your other posts. You appear to have tuning issues. If your car was perfectly tuned with the modifications that you have, it should be a lot faster, REGARDLESS OF EXHAUST.

It seems that you have been having carburator tuning problems but blame the exhuast. Stop doing that. I have some questions for you:

-how is your ignition set up?
-what is your carb setup currently?
-what is your compression?
-who ported/built the engine?
-what are your vacuum readings at idle?
-what is your driving technique?
-what other changes did you make at the time you ran open header?

Post the two timeslips between the two exhausts. You also neglect to state the mph through the traps. This is a better indicator of power than et.

I have run straight exhausts. The power difference was not noticeable but the noise was unbearable. The RB street port exhaust is not hurting the performance of stock and street ported engines.

I am all for people experimenting and testing, it's what makes things better, but your statements don't have proper testing or consistency to back it up.

The fact that you ran a 10.xx 1/8 mile with a streetport 12A, Holley, exhaust, igniton,etc. is just plain slow. This would equate to a mid to high 15 sec 1/4mi. This in itself is an indication of poor tuning.

Just don't blame the exhaust.

kuhlrx7

I am not a big RB exhust fan but I have to agree with dvcn dont blame it on the RB exhuast. when my rx was stock 79 I did better than that. with 12a large street port and mukuni intake and carb, RE header RB dual exhuast , stock dizy I did better than dvcn. now I dont play 12a its 13bt and custom dynomax,edelbrock, vibrant ss bends and tubes. but on a 12a if exhuast sound level is no issue look at http://www.iscracing.net/ It is a little large in dia but will most likly make you happy. 2 1/4 - 2 1/2 is a better dia for the 12a regarding low end grunt.

813KR$

Just to let you know Iam not a RB hater just becoming one. I used to love RB until now Iam getting alot of hands on experience. For example why in the world would a company that works with rotories make a heat shield and have american size nuts instead of metric? A small insight. I could go on!

My timming is slightly advanced

carb is a Holley 600 with no choke, primaries and secondaries opening at the same time, 59 jets prims(need to richen prims since I port matched my intake, **** RB intake which the ports dont match, pimary runners were way too small. Have not ran my car since I opened the intake) 65 jets secs

Havent check compression, havent had a reason to check only 8,000 miles on engine

Have not checked idle vacuum

Drining technique W. O. T.

The only other changes I made was increased tire pressure which made my tires spin more. Everything was exact it was the same night on a very slick track. My best time on that track before that night was 9.9 1/8th mile, but on the specifeid night was 10.0

CrazyJoe12a

My 82 went 9.9 at 70 with a stock port, RB header and stock carb. This was only my 2nd time drag racing and I spun the tires through 1st and 2nd. I think a Holley carb'd SP should be faster....

dvcn

What? What does this have to do with anything? How does the thread size and pitch make RB a bad company?

What does this mean? What is the total advance? Locked timing? Are you running vacuum advance? What plugs? What wires? Have you tested your wires with a voltmeter?

Let's assume this jetting is more suited to open headers, have you jetted for the street port exhaust? Are you saying that the RB Holley intake manifold is restricting the power of your street port 12A? They make the ports smaller for a few reasons. Do you want them to make them huge so that you have to attempt to match your side housings to the manifold instead of the other way around? Another reason for it is reversion, but we won't even get into that. Why are your primaries and secondaries opening at the same time? I can't think of any reason to do that. Unless you have upgraded to 50cc accelerator pumps and tuned that system I can only see really poor low end response coming from that setup.

A newly rebuilt engine is guaranteed to have good compression? You didn't say who built/ported the engine and if all the seals were new. Housings resurfaced? What else was done internally?

What does this mean? You launch at 13,000rpms? I want you to post your full timeslips. You need to compare apples to apples. How do you launch? I want to see your 60' times. I want to see scanned timeslips.

If you can get past the abuse, you will find that answering these questions will help make your car as fast as it should be.

I really can't understand why you still insist on complaining about RB. You want them to give you information on the carb that they spent a load of money testing, building and stocking for free. Do you work for free? In the end, for most people the purchasing a Holley directly from RB is the most pain free and economical way to go.

DriveFast7

iTrader: (1)

RB Primaflow does not kill power on a street/strip car but a straight thru 2.5" magnaflow will add more power and more noise. Still noise legal but gotta lift with cop shows up. been there, done that.

My RB Primaflow died after roughly 5 years of use including several weekends hotlapping on tracks. Packing came apart and when I shook it I heard it rolling around. BUT that muffler definately made my car sound legal and I never had to lift for 5-0.

813KR$

The american nut size is a pet pive! Well they are making them for the rotary, right?

Dont know much about timming, I have it advanced enough t run right, but not too far advanced. I have the vacuum advance diconnected and the trailing is fully advanced and locked. Stock generic denso plugs. Newer stock wires, never checked with voltmeter.

I set my jetting as rich as possible, then try to lean out slightly? Probably wrong, but how else do I try to get it right? The ports dont even line up straight on the intake to the engine, the seconderies are slightly off center. I have also richened my primaries since I last posted Iam currently running 62's prims and still 65's secs. Yes, the intake was restricting flow into the engine. I have prims and secs open at the same time, because I dont use the vac for the secs and dont want the secs to open while running and lean the mix becuase I dont have a doubl pumper.

I dont know much about the rebuild, it was a friend of a friend type of thing. Supposedly has used but good apex seals and street ported(dont think it is a big sp).

W.O.T. means I launch at 4000-4500 rpms and try to get to the other end as fast as possible, trying not to spin to much. I dont have many runs under my belt!

I complain about RB, because they act like they are god and give half *** service/products? Maybe not to those extremes, but close enough.

dvcn

My biggest pet peeve is people don't properly tune their car and blame parts, companies or other people. Tuning is everything! I get tired of hearing myself say that! Please spend the time to tune every system on your car.

The ignition system is really important. I can't stress that enough. A long time ago I had a full J-bridge 1900lb RX-3 with a 125hp nitrous shot and slicks. I ran a 14.65 in the 1/4 all because of a bad leading coil wire.

Learn how to set your timing. The Yaw total timing settings work great on a street/strip car. Do it. If you don't know what 'total' timing and what the Yaw settings are, please do a search for it. Wires matter. My personal favorites are the MSD Superconductors, they have around 50 ohms per foot resistance. I will make a custom length set that you specify and ship it to you. A good and economical plug to run is the NGK BR9EQ-14.
Please don't say that the trailing is fully advanced.......

Please go here and read:
http://www.holley.com/HiOctn/TechSer...o/FMCTech.html
I feel you have several issues with the carb. I don't understand the misalignment. I have two Holley carbs and two RB manifolds and the bores align pretty well. If there is a huge misalignment match port the manifold or get a new carb.
Mechanically converting a vacuum secondary carb to mechanical will cause a lean stumble due to the lack of an accelerator pump on the secondary circuit. This is bad for any kind of responsive acceleration.
I still don't understand your carb setup. All I can say is that small jetting changes makes a big difference in performance. It is very time consuming but it must be done.

You must realize that if your apex seals, side seals, corner seals, all springs, etc. aren't working perfectly, you won't make power! What goes into an engine and how it is assembled does matter. Porting matters. This is a huge question mark.

I asked for your time slips. The lauch/60' is everything when it comes to the 1/8th or 1/4 mile. The mph through the traps is a better engine tuning indicator as it is relatively consistent as compared to ET's. The trap speed is an indicator of horsepower. Launch technique, shift technique and shift rpm all make a difference in ET. BTW, I just realized that I have 175-225 passes down the 1/4.

Again, show us the timeslips!

Let's say that you have a company that makes quality products for the general public for almost 30 years. (I think I'm repeating myself) You spend time and money making a really old design carburetor work on a Mazda rotary. Someone calls up who bought a used old probably damaged carb and wants all the tips, tricks and specs to make it good. Why should they give this info to you or anyone else? Call up any manufacturer on earth and ask them for proprietary specifications and see what happens.

813KR$, please go through every system on your car. First make sure it is functional then tune it for performance. Guessing, not knowing and bashing RB do absolutely nothing to making your car faster.

813KR$

No one is bashing RB, just stateing facts. I dont understand why you keep on talking about them not giving any tips on Holley's, I havent said anything about that in this thread?

The misalignment has nothing to do with the carb, it has to do with the intake to engine, which is about an 1/8th inch off, or less?

The plugs I have are Denso and basically the same as the br9eq14, just Denso instead of NGK.

I have to pull out my slips to quote from them.

Iam in the process of tuning my car, that is where the test and tune comes in play. No matter how much you want to talk down to me, rotories run with more power with headers only, no matter how the car is tuned, you take that muffler off after you are totally tuned and it will run smoother, respond better, and pull harder. Compared to the RB muffler, plain and simple!

kuhlrx7

813jr$ you are wrong about the runing better with just a header thing. step back and take the help being offered even with the tone used. you will be happy you did latter. you may want to rethink your carb. the holley 600 is not the best for a rotary. and unless it has the mods for rotary use you will allways wonder why you are slower or never able to keep it running right you might try looking at paul yaws site... for some of this info regarding the mods to the carb.

widnerkj

One of my buddies at work used to work for mazdatrix, he said that they put a set of corvette mufflers on a 13B and ran it on an engine dyno. The mufflers lasted for 8 seconds before they exploded. But he did say to be really picky and unafraid to spend a lot for your exhaust system.

iluvmy85

I have a 85 GS and i am going to put in a 13b TII and i need to know if that will be good for the car? it will be making at least 230 Hp

813KR$

TII conversion @ 230hp sound good to me! Why wouldnt it be?

I was at the track again last night, 9.8 with rb exhaust 9.5 headers only! It is all about comprimise quiet = 3/10's slower than loud as hell. Not a bad comprimise considering how much quieter it is ! ! !

DVCN: what is your 1/8th times? I see you 1/4 is 13.8.