I know this has been discussed a milion times, but now that I've gotten rid of the cats and emission crap I need to decide if I'm going to just do the complete exhaust.

There seems to be little seat of the pants gain just removing all the cats. Will aheader actualy give me much more. Or is this something I won't really feel a huge difference in? Does it make that much difference b/t brands/styles of header? I did some searching and couldn't find any actual dyno RWHP results from header alone.

A headers is cheap enough but I just need to have actual power gain evidance on paper. So I can justify buying myself one...

Again this is suppose to be my daily but I'm retarded and can't just leave things alone.

 

Well honestly most of us FB guys are pretty petty... I am unaware of anyone who has dynoed before and after header, but when it comes to a header anything but Racing beat is a mistake. I cannot say myself if the header itself adds all the power, this is because I installed my whole RB system at once. But anything is better then the stock exhaust manifold....

 

The header is just a piece of the puzzle.You need a full exhaust in order to reap the benefits.By itself,even a full exhaust system (header,delete cat,muffler) is only worth about 10-15hp,but thats a 10-15% gain over stock and it also saves you quite a bit of weight over the stock system,and weight reduction gives you an all around gain.The installation of a complete exhaust is more a preparation for bigger,future mods like a carb,porting,MSD directfire,nitrous,ect......which require that the engine be able to breathe out freely.
Having any header with the stock muffler isnt going to make much difference.It will however change the exhaust sound quite a bit, due to exhaust pulse timing.

The 2 most noticable mods Ive ever done with a stock 12A were....
Light flywheel....really wakes up the first 3 gears.Makes a rotary rev like it should.Very fun and nearly no downside,except cost.

MSD directfire w/3 Blaster coils.....perfect idle,more punch at any speed,even helps with smog.Not too expensive,you can piece it together with used stuff and FC parts.

 

The single most largest power gain for a stock engine will be from replacing the cats with a straight pipe of some sort. Adding a header will only add a little more to it plus move the power band up.

 

Arg... well I guess I'll spend my money elsewhere. I'll take you up on that flywheel when my clutch goes. I've got 70k or so on this one how long do they last with normal driving? Maybe add in an alum driveshaft and some light weight race wheels at the same time?

And I'll look into the MSD directfire w/3 Blaster coils. What are the strongest coils you can buy to fit in the factory spots?

Honestly I was only going to do exhaust and intake (now possible ign) and call it a day for this car. Would switching to a small 4bbl holley be beneficial for a daily? I figured I could set the main jets down a bit and pick up some MPG off it. Not to mention electric choke and cheap parts.

Thanks alot everyone I'll leave the header out of this daily driver for now.

 

whoa whoa whoa.
damn near everythread i've read says that the header alone supposedly gives a 30hp increase.
WTF yo?

 

Pace advertises "UP to 6 hp". Maybe flywheel with an open header....

 

[QUOTE=steve84GS TII]The header is just a piece of the puzzle.You need a full exhaust in order to reap the benefits.By itself,even a full exhaust system (header,delete cat,muffler) is only worth about 10-15hp,but thats a 10-15% gain
over stock and it also saves you quite a bit of weight over the stock system,

I agree completely. Upgrading the whole system, legally, will give you around 12% increase at best. The header is only part of this sysem, and just improving this will give you 5% if you are lucky.

Thisv is less than the benefit of a decent tune up, change of plugs etc. Going for a lighter flywheel will not give you more power but certainly a more responsive engine.

 

All Mazda rotary engines are very much restricted on intake and exhaust. So a header does help, although to take full advance of it, you'd need the rest of the exhaust too. Other way the cats (if you have them, overhere we never got cats on first gens) or mufflers will just be bottlenecks. A full exhaust, and a good carb will add quite some power. But like most people, a lot of owners tend to think in numbers way too large. As stated above, a 10-15hp gain is over 10%! That's a lot! A stock ported engine, with a decent carb and exhaust can get around 150hp (flywheel) and that's really a serious improvement if you think about the fact that it started with aprox. 115hp!
Flywheels, again as stated above, won't add power, but make the engine rev easier. You must keep in mind that roll-off and uphill drives will be a bit less easy, and you'll need to shift down earlier, due to lack of "mass" in the flywheel.

 

A good header is WELL worth it.

 

I do agree there. It's just not going to a 30hp mod. Then again, apart from porting, no mod is going to bring you 30hp or more at once.
Personally, I'd go for a full system but a header is a good start, just buy a good one (RB)

 

when i added on my fc the whole exhaust system i got 19 and they (racing beat) claimed 21 thats pretty good for a header and presilencer n muffler

 

Except for a 50 shot of nitrious mod!

I had my exhaust done today. Just had a straight pipe installed between the manifold and a new factory victoria british muffler.

If I accelerate hard It's actually a little louder than I'd like. Sounds just like all the other fart can ricers. But at cruise is quiets down nicely. I'm happy with it for now. And it definatly feels a little faster.

In a month or so I'll put a RB header and install a silencer inline with the stock muffler as well. These two will probably cancel each other out power wise but I'm ok with that, as long as it quiets it down a little more and cleans up the engine bay.

Over all I got rid of my emissions air pump (soon to do the rat nest removal) which dropped off some weight and free'd u a tiny bit of power and ditched all the cats. Car is more responsive and I think my engine is thanking me already... I'm very happy with the results.


Thanks all!

 

So the general consensious here is that a decent intake like a RB setup w/ a RB full exhaust for example will yield approx. 150 flywheel HP?

 

around that... yes. 83gsNC on this forum had that exact setup and it was pretty quick.

 

Yaw quoted that on a stockport 12A with full exhaust system with his nikki/intake manifold would yeild 150 crank HP.....a 50% gain over stock!
And thats about what it felt like when I ran it.Drove like a normal car down low,had a very nice kick in power around 3500RPM to redline.The same setup on my stock port 13B yeilded a more linear torque curve and maybe a few more HP.
His carb is nearly double the airflow of a stocker,so dont expect a 50HP gain by just adding a K&N filter and/or an SA intake manifold.....you.ll need a carb that can flow and deliver fuel to match,in order to get around 150HP.

 

I highley doubt it, you would need those two things and a ported motor.

 

If it was tuned properly you should get around 150hp at the flywheel with a good stock engine, aftermarket carb and intake and good exhaust including headers, you should also gain a little MPG when driven gently, ha like that'll happen...lol

Oh and ignition upgrades also...

 

Your're kidding right? Those things and a ported motor would put you on the north side of 150hp, Closer to 200.

 

I can garuntee you that I'm not running anywhere near 200 RWHP.
I have a Yaw carb (recently **** out on me, trying to get a refund on it to get a Sterling), decent streetport, full on Racing Beat sp exhaust, ported intake, rat's nest/air pump removal, removed AC, and a shank load of weight reduction mods (if it aint necessary or a dash, it aint in the car!)

If I was cranking 200 HP with that setup, I'd be in the low 14's, which I'm certainly not.
In my last run before the carb **** out, I clocked myself at 15.4 in the quarter (according to my odometer and a stopwatch). Given to the error of the equipment used, the BEST I could be running is fifteen flat. With a 2200 lbs body, that's NOT a 200 HP car.

 

Jay,

they were talking Flywheel HP not RWHP

kenn

 

91283749p8

 

Yeah what he said.

 

Like others have said already, the header is just one part of the puzzle. It is an excellent place to start, because it will increase the gains of any other mod that is done in the future. A Sterling carb used on a stock car will not be a whopper of an improvement, but if you add the nice exhaust and free up the intake it will be a monster. It all goes hand in hand. I have the RB full system and a Sterling and my little car is a rocket. But if I only had one or the other, that would not be the case. Just like building a house, it won't be for **** if you don't give it a good foundation. A header alone won't give you much, but without a header you won't get anything appreciable out of any future mods either.

 

Exactly. You can't just add random performance parts on and expect huge gains. Every part of the engine works together and changing one thing will affect the others, negatively or positively. You have to upgrade so that each part works in conjunction with each other. That way the system can perform effectively as a whole. You'll see hp with a header alone but even more when you upgrade the other parts that are connected to it; ignition, intake, exhaust, etc.