460 Ford Forum banner

1 - 20 of 24 Posts

·
Registered
Joined
·
91 Posts
Discussion Starter #1
hey guys.. ok Im a little confused as to how big my exhaust system should be..

so far im leaning towards D&D headers but 2-1/8" primaries... but for the rest of the exhaust, Im not sure if I should go with a 3" or 3.5" system, exiting before the rear axle.

also, im looking into magnaflows and maybe this dynatech cone turndown to further reduce the decibles without causing backpressure.

my combo:

545 w/ about 10.5:1 comp, P-51 heads out of box, hydraulic roller cam with about .643/.635" valve lift and 253/248 @ .50 duration with a 112 LSA, 1050 dominator and edelbrock victor manifold.. also using 3.73 gear with a 28" tall tire.... the project hasnt even begun yet, but i want to plan everything out before i start... i think at the end of the project, the '85 T-bird that we're building should weight around 3300 pounds... possibly, and also making at least 680 [email protected] 6000 with about 700 ib-ft peak @ 4500


also i want to know if i should go with an H- or X-pipe... or none if not recommended... but i want something that is going to be optimal for performance but also quiet enough not to bother the neighbors... besides the fact that the exhaust pulses will probably blow up my house .... yea...


but anyways, besides knowing that most of my questions should be answered upon my own opinion, id like to hear what others may think might be the way to go ;-)
 

·
Banned
Joined
·
2,451 Posts
As big as you can fit IMO
 

·
Premium Member
Joined
·
1,957 Posts
I have crush bent 3" exhaust all the way out behinf the wheels, no H or X and running Flowtech Afterburner mufflers. The headers are 2-1/8" to 3-1/2" collectors, with reducers taking it down to 3"

The car runs one tenth slower with the exhaust connected vs. 12" collector extensions.

My conclusion is that the crush bent stuff, while not that easy on the eye, isn't hurting my times much so the flow must be sufficient.

Our combos are not that much different (you've got better heads for sure, though) so I would expect similar results in your case.

Good luck,

Greg
 

·
Registered
Joined
·
10,854 Posts
Is this for a turbo engine ...?
That camshaft is WAY out of the ballpark; in just about ALL respects.
 

·
Registered
Joined
·
201 Posts
3 will be quieter them 3.5 . ? i don't think you could go wrong with either one . i don't think you will feel a difference in power . if you dump it before the axles it don't matter what size you go with it won't be quiet . tailpipes will help and all mufflers work best with at least 18 inchs of pipe on the back of them .
 

·
Registered
Joined
·
91 Posts
Discussion Starter #10
i didnt state that i would be running a turbo, so obviously not lol. turbo's dont need wild cams... but anyways thats a different story..

im still deciding whether or not to dump or use tail pipes... but im thinking that ill just dump the exhaust before the axle and use a set of maganflows.. and if thats not quiet enough.. maybe ill put bullets or moroso spirals after it to quiet it a little further without backpressure..


i was thinking 3.5".. but im not sure if i should just go for the 3" or not.. if i go 3" , i can just go ahead and get a universal exhaust from Jegs rather than having custom work done... but in the end, what really matters is what will be optimal for the motor..

definitely im gona run 2-1/8" headers... but maybe since im gonna be using straight through mufflers and probably dump before the axle.. i can probably just go with a 3" exhaust..


i still need to ask around about that
 

·
Registered
Joined
·
6,697 Posts

·
Registered
Joined
·
91 Posts
Discussion Starter #13
well i do know that hot gases move fast than cold gases..

maybe ill just stick with 3" exhaust piping and be happy with it... and done too lol


but definitely im gonna need to use maganflows to quiet it down.. i wouldnt use just spiral mufflers.. but along with maganflows they make help make a unique tone to the exhaust..

or maybe use Pypes race pro mufflers or violators and spirals... i want something totally different than anybody else ;-)
 

·
Registered
Joined
·
10,854 Posts
WILD cam??? Hardly ... it's simply that the camshaft you listed is just north of a piece of trash with that combination when used in an NA situation.

Good Luck, you'll need it.
 

·
Premium Member
Joined
·
1,311 Posts
Another option is oval tubing...it is sort-of in the middle between a 3.0-3.5 in.
Dr. Gas website has info.

I believe a 4 inch oval is equivalent to a 3.25 in. round, as far as cfm of flow rating. They measure 2.5 in. tall and 4 inch wide.

These are the pipes I am thinking of going to on my T-Bird.
 

·
Registered
Joined
·
201 Posts
i don't know if this will help but i had a s-10 standard cab short box with a 350 chevy . motor had stock bottom end 9 to 1 compression , world product iron heads , with 2.02 intake valves and 1.60 exhaust valves . had a 268 @ .050 duration cam with 456 lift at the valve with a 110 lobe spread . had a holley dual plane intake , 373 rear end gear , 1 5/8 long tube header with 3 inch colletor . i ran 2 1/2 exhaust pipe off the header and in to a flowmaster y- collector that turned in to a 3 inch single exhaust pipe with a flowmaster super 40 muffler and a tail pipe that turned out behind the rear wheel and with a 150 shot of nitrous . the truck ran 11.80 in the 1/4 at 118 mph . all the exhaust pipe was mandrel bend all the way out the back . had a alburn posi with mickey thompson et streets 26/10.5-15 . i never would have guess that truck would have gone that fast . i know you have a lot more motor . maybe this will give you some help on what you want and how big is to big . hope this help . good luck with your project man !!
 

·
Registered
Joined
·
2,673 Posts
393,

I believe what Randy is subtlety :D trying to point to is your camshaft specs. It looks like you have them backwards. Those are more of a turbo spec, LOL. Not only that, but it is going to take more camshaft than that for "at least 680 hp". Drop the hydraulic roller and go solid roller.

BTW: "besides knowing that most of my questions should be answered upon my own opinion" What does that mean???

LMAO.

You could have said, "since I'm a legend in my own mind".

LOL.

C'mon, give me a break.

:D

Dave
 

·
Registered
Joined
·
91 Posts
Discussion Starter #18
1st off, I really don't care what anybody thinks about my combination. If I were to have asked a question upon, I guess that would mean I do care.... and the camshaft specs are as is, not reversed (I'm more than sure). Plus which I was thinking the same thing when my cam was recommended to me... If you don't like the combo, go talk to the guys at FPS about it, not me... I asked for a specific type of engine to my own liking, and this is what I have..

All I know is that, I know when I'm happy, and so far I am :D



Anyways, all that "other" stuff aside.. if you have any EXHAUST recommendations, I'll greatly appreciate it ;)
 

·
Registered
Joined
·
91 Posts
Discussion Starter #19
btw..

"besides knowing that most of my questions should be answered upon my own opinion"


I said that because, I do have an opinion as to what I should do with my exhaust.. go 3"... 3.5".. whatever... either way I'm sure that the best for my combination at a TRACK would be 3.5".. (top-end reasons)... but then again, I could be wrong! ... maybe 3" is better for the track, or the whole RPM range..

but also in my mind so far, I feel that 3" would be best for the street..


I'm only asking these questions because I'm expecting to get some solid and accurate answer since this is a 460 oriented site... isn't it?
 

·
Registered
Joined
·
156 Posts
exhaust science

The following link was ORIGINALLY published in Popular hot rodding in 2005 so dont run away from the super chev title. Your exhaust is not brand sensitive!

Worth reading a few times!

http://www.superchevy.com/technical/engines_drivetrain/exhaust/0505phr_exh/index.html

Of particular interest pay very close attention to using pressure wave termination boxes.

essentially what the boxes do is isolate your power tuned header system from being affected by your quieting system. The article shows vizards reasonably acceptable sound level, near zero loss system, losing only a few hp at a true 700 hp level. Also important info on header sizing collector sizing x pipe h pipe and exhaust muffler flow requirements.

Not utilizing a pressure wave termination box effectively lengthens the collector killing power making reflected wave tuning scavenge effects.

Pipe max program is also another worthwhile investment for determining your header/collector size needs.

BTW two 3" open pipes can support @ 700 hp 2.5" around 500 hp
 
1 - 20 of 24 Posts
Top