Header questions

[mp3boy1984]

alright i once had the awr header installed but then got rid of it because i thought i was going to get rid of the car.......but now i have decided to keep the car....my question is what kind of power differences am i going to notice with a 421 vs. a 41 header......41 headers are cheaper so i am really looking at those......i looked at the official header thread but it mainly talks about emissions and what not, i am not really concerned with emissions cuz i live in michigan and i already don't have my second cat....also what are the sound differences and which one is going to sound meaner, i want my car to sound as mean as it can be as well

 

[viVid]

I don't think the AWR 4-2-1 header is worth more than twice the price of a 4-1... you certainly won't get twice the HP (maybe just a bit more in the mid range - but you'll lose it up top).

alright i once had the awr header installed but then got rid of it because i thought i was going to get rid of the car.......but now i have decided to keep the car....my question is what kind of power differences am i going to notice with a 421 vs. a 41 header......41 headers are cheaper so i am really looking at those......i looked at the official header thread but it mainly talks about emissions and what not, i am not really concerned with emissions cuz i live in michigan and i already don't have my second cat....also what are the sound differences and which one is going to sound meaner, i want my car to sound as mean as it can be as well

 

[p5sundevil]

the meanest sounding one? probably the AWR unit you originally had as it is a true race header sismilar to the ones woodford makes for the wrc cars he sponsors.

Otherwise the other options would be the OBX/Forza 4-1, ractive 4-1 and the OBX 4-2-1 from the 626/probe models and have a testpipe made to make it fit.
out of these three they should all be similar in tone. maybe the 4-2-1 slightly different but not necessarily louder.

 

[Gen1GT]

4-1 headers are best for peak power, as they can be tuned. Everyone says the AWR is a good header, so why not keep that one?

 

[p5sundevil]

i assume he already sold his old AWR and at the going price of the new ones, especially in SS it is not worth the extra 2-4whp that you "could" "Possibly" get from that unit over the lesser expensive ones.

 

[SpicyMchaggis]

get the 4-1..it'll sound nasty..btw..just one more plug..if you want to know what it sounsd like to run a 4-1 w/o cats or muffler..check it..

http://www2.msprotege.com/forum/showthread.php?p=1084530#post1084530

thats enough promoting for one day..

 

[akhilleus]

I second that...If u could hear and feel mine u would want one too

 

[mp3boy1984]

alright i once had the awr header installed but then got rid of it because i thought i was going to get rid of the car.......but now i have decided to keep the car....that is the reason i got rid of the header.....i loved the sound of my awr header.....how are the 4-1 headers tunable?

 

[mp3boy1984]

also, i read somewhere that smaller exhaust piping will help maintain lower end power, i am just curious if this is correct

 

[p5sundevil]

yah for an NA build dont really need anything bigger than 2.25" piping in the exhaust system, maybe the racing beat which is like 2.375 or something at most. need to retain some backpressure and whatnot for torque and low end power. basic cave man description anyway =)

 

[Gen1GT]

yah for an NA build dont really need anything bigger than 2.25" piping in the exhaust system, maybe the racing beat which is like 2.375 or something at most. need to retain some backpressure and whatnot for torque and low end power. basic cave man description anyway =)

Oh no you didn't!

Velocity, not backpressure is what you're looking for. 2.25" is normally perfect for a smaller 4 cyl. I chose 2.5" because of the mods I'm going to be doing, and how high I'm going to be running(future 8000-8500RPM redline, 170whp). As you can see, I haven't made any gains with any of my mods below about 4400RPM(66mph, I mistakenly printed the MPH graph instead of RPM. The red line runs to 7400 or 113MPH in 4th), but it really opens it up, up high. But 2.25" would be perfect for your needs.

 

[glyph]

Another question to throw in the mix: I have a 1.8L 99 ES, and am looking at headers. I see the AWR header for $570, which removes the first cat, or the OBX header for $240 which is a direct bolt-on?

 

[shinzen]

Both remove the first cat- as to bolt on for the 1.8- someone can answer it for you, I am not positive- The header comparison has been discussed quite a bit- obx=forza

 

[Gen1GT]

Another question to throw in the mix: I have a 1.8L 99 ES, and am looking at headers. I see the AWR header for $570, which removes the first cat, or the OBX header for $240 which is a direct bolt-on?

Please, please, please tell me you want to do a serious build-up on your FP? I'd like to see what the upper limits of that engine are, like how high it can rev, and what kind of power it can make. All bolt-ons that fit the 2.0, will fit your car. The FS is just a stroked FP. Everyone says good things about the AWR, so why not go for it.

I'll bet the 10:1 BP pistons would be a pretty good fit in the FP....

 

[Gen1GT]

alright i once had the awr header installed but then got rid of it because i thought i was going to get rid of the car.......but now i have decided to keep the car....that is the reason i got rid of the header.....i loved the sound of my awr header.....how are the 4-1 headers tunable?

4-1 headers are tunable, by how long you make your primaries. The longer the primary, the lower in the powerband it's tuned to. I'm going to be using 36" primaries, which should tune my exhaust system to around 6500-7000RPM. Which means I'll get a 3-4hp hump around that RPM over an untuned header, or a 4-2-1 design. If the primaries were say 45" long, that hump might be around 5000RPM. It's kind of like a tuned port on a subwoofer. It takes advantage of a pressure wave that travels down the primary when the exhaust valve opens. That pressure wave travels back up the other primaries in time to bounce back again, creating a negative wave just in time for it's exhaust valve to open, drawing out the spent charge. Because the pressure wave travels at the speed of sound, this can only happen at a specific RPM, which is the RPM you tune it to.

 

[glyph]

that makes sense. I did not know that about the header primary length.

I really do want to do a solid build up, but money is the real issue. There is also the lack of options for the 1.8. However, you say the 2.0 is just a stroked 1.8... what would it take to stroke the 1.8 that far? (if possible, I am a noob to this stuff still; working to learn it all, though).

From what I have read so far, the AWR is the better header, but it is over twice the cost. I have a lot of nice thoughts regarding building the engine NA, then eventually adding a turbo. I do plan on keeping the car for quite a while, and put the money for a new car into a new house and this car. I had followed the old NA threads for quite a while and learned a bit, but still nowhere near knowledgeable yet. Plus, it is hard to discern principles from different opinions.

 

[mp3boy1984]

alright, well i don't intend on staying all motor, as i plan on adding nitrous.....so what size piping would you recommend then?

 

[Gen1GT]

alright, well i don't intend on staying all motor, as i plan on adding nitrous.....so what size piping would you recommend then?

You mean for a header, or for exhaust? If you're gonna do some crazy nitrous, I'd recommend 2.5" exhaust. You're gonna have a lot of spent gases to expel.

glyph, The like I said, the FS-DE(the newer 2.0) is just a stroked version of your FP-DE(1.8). It was an easy way for Mazda to make a few more ponies without doing a whole lot else. 122hp vs 130hp. The thing is, the FS has an EXTREMELY short rod for how long it's stroke is. What this means, is that the reciprocating assembly(ie pistons and rod small end) has MASSIVE g-loads, because of the rate it accelerates to and from Top Dead Centre. There are advantages(like extreme resistance to knock/ping), but disadvantages like not being able to rev high, before you break an already weak rod, or throw a piston. It just doesn't want to rev. The FP and FS have the same block, which means with a shorter stroke, the FP will have longer rods. The FS has 135.2mm rods and a 92mm stroke, giving it a very low 1.47 rod ratio. Assuming the pistons have the same compression height(distance from the piston pin to the top of the piston), and the same deck height(distance from the top of the piston to the cylinder head), it would mean the FP would have a 142.2mm rod(probably less. I'm assuming the piston CH is higher, but we'll go with this number for now). Now considering the 85mm stroke, it would have an excellent rod ratio of 1.71. This should allow the FP to rev extremely high, and do it all day long.

What I would like to see, is a good FP buildup. Everything that bolts to the FS(intake, header etc etc) will bolt to your engine, and I see no reason FS cams and pistons won't work too. If not, you can use the BP 10:1 pistons, which can be had for less than $50/each. If you make custom rods(which you would want to do on a serious FS/FP build-up, since they're that engine's weak point), to go with those pistons, you could have a screamer on your hands. I think some of the other guys in the club wouldn't mind seeing what an FS can do too. An FP with an 8000RPM redline would be something sweet....