I have a full Mufflex 4" cat-back. Hooker 2210 headers, and a 3" to 4" Y-pipe.

I have a spintech muffler.

To make the car quieter, I installed these



The car doesn't make the power it should and it is a BIG cam'ed motor. So it moves a LOT of air. Think that some of the power I am loosing is due to this?

I guess the car might get a little louder, but if I can pick up more power, then screw it. I want it.

I was talking to a friend and he told me that they effected the his chevelle so much that he had to really re-tune it after he took them out due to the improved flow.

What do you guys think of that. (his chevelle was making a little over 1000 HP with a SC big block)

 

Is this a TPI motor? If so these engines are not really intended to run with a big cam. The intake is designed for low rpm high torque, and the big cam is designed for high rpm high horsepower. Just a thought.

 

No, I am aware of the TPI power band. This is a totoally differnt motor. Purpose built for high RPM. Forged internals, N20, the works and so on.

 

its the spintech muffler if anything.
put on a dynomax ultra flo welded and call it a day!
you wont need the silencer thing then.
my car is super quiet. and it makes close to 450 at the wheels.

 

I love my spintech and wouldn't give it up for anything, even if it robs some power.

 

That makes absolutely no sense at all. Why would you leave a muffler on your car that robbed power. I'm sure it doesn't sound so good that people are like, "Man, that dude must be running a Spintech!" It's just a muffler. It's OK to let it go.

 

WTF are you all talking about!!!!!!!

I have a 4" cat-back, I REALLY don't think that muffler is plugging up ANYTHING! When I had it off the car you can blow thought it and feel your breath on the other side. The spintech is NOT plugging up any thing, I garontee you on that.


Back on topic. I am talking about the header mufflers posted above. Anyone have any eperience with removing them or anything like that (point of this thread).

Thanks.

 

your breath has nothing to do with velocity or engine pulses going through the muffler at any given time.
people have reported 5-10-20hp gains by switching to other mufflers.
i had one on mine and went from 93mph 1/8 mile to 95.55mph with a muffler switch. and thats going from a 4" spintech to only a THREE inch dynomax necked down with a reducer.
dynomax or magnaflow man.
all i can say.

 

Is it possible that the 4" pipes are TOO big, for the engine? No engie info makes it harder to determine that. If you are playing in the 1000hp range, like your friend, never mind...you need the 4" pipes. A bit smaller might help keep gas velocity up & increase your power.

Bigger is not ALWAYS better. Maybe the pipe size? Just a thought.

 

single 4 inch flows 1400 cfm and is good for 636 n/a hp based on the 2.2 cfm per hp rule.

The exhaust is not too big, its probly the muffler thats not making the power yet still loud. i would try a straight thru muffler like ultraflo round for more quiet setup, or borla XR1 or dynatech split flow for a straight thru that has alittle sound reduction designed for max power

i went with a dynatech split flow for my 4 inch i'm building. We'll see how it sounds and performs

i have heard spintech restricts power on some of their models. I think the flowmaster single chamber race is a better muffler than the spintech option on mufflexs

 

i saw a buddy gain something insane like 12mph in the quarter by going from the spintech to a dynomax ultraflow...his motor is in the same realm as yours, so i think that the spintech would be the problem. seriously.

 

i'm not too knowledgable about spintech mufflers myself but that silencer will restrict some flow but like stated above not really sure what kind of engine your running i mean if you built yourself a high rpm 350 and your only pushin 500 hp 4" is too big
too high of backpressure is bad but too low backpressure is also bad either way u lose HP and probably extra un needed wear on your engine

 

The mufflex 4" system is recommended for 400+hp .....the 4" is not too big.

 

i'm still holding at 500 hp since out of everything i've heard everyones equation on horsepower 4" as u say i've heard from 400 hp to 700 hp is a good starting point for 4" so 500 is about average
not to mention earlier in post someone stated 600 was a good hp for 4"

 

Yes its not really a 'backpressure' thing, but more of flow requirements and correct total length of the exhaust system.

A great exhaust system will have zero net loss over headers/collectors that are open and of the correct length. there are ways to build this and there is a thread i started discussing ways to do it, but on our cars is difficult to do such builds. Just no clearance to work with

His motor should be around 500hp from specs but i'm not sure what its putting down or what he runs

500 hp needs 1100 cfm of exhaust flow. General rule of thumb from exhaust experiments conducted by some top engine builders states 2.2 cfm required per hp. 500 x 2.2 = 1100 cfm. 3.5" single pipe flows 1105 cfm at 28" water. 4inch flows i believe 1440 cfm... so in a sense, 4inch is a TAD overkill but its best to be slightly overkill than under gunned here.

Doesnt matter what the pipe flows since the muffler is where the restriction is. IF your muffler doesnt flow 1100cfm your not getting full engine power. a 4inch spintech needs to flow 1100 cfm but i dont think they do. If its flowing 800 cfm, then doesnt matter if you have 3.5 or 5 inch exhaust, your smallest point in the system is that muffler and your only gonna flow 800cfm. I guess thats where "backpressure" builds up..its just a restriction in the flow and that will help ruin the exhaust scavenging effects at the header

Dynomax ultraflo 2.5" inlet/outlet is said to flow 1133 cfm. So the 4inch has to be above that. I got a dynatech split flow and its straight thru. I'm not sure of the flow numbers on it but it would appear to me to flow near as much as a 4inch straight pipe since its straight thru. considering the divider in the muffler restricts alittle flow as well as the tiny holes for sound reduction, I would expect atleast 1200 cfm flow which will be enough to feed my motor which should also be around 500 hp if not more.

 

nice
i've never had nething over 400hp myself so i've never really had to worry about my exhaust 2.5 duals xpipe pr a single 3" was always enough
thx for clearing that up a bit

 

ultra flo muffler without a doubt....you WILL pick up ET and mph.

 

wasn't there a thread on here bout a month or two ago about mufflers where a guy claimed to gain some absurd amount, like 60 horse, by removing his spintech and using a dynoflow or something instead?

 

yep i believe it may have been EvilCartman but i'm not sure. i remember reading it and basically a exhaust change made some ridiculous gains

 

One more vote for the Delta Force Single Chamber!!!!

 

Thats great about the straight though designs, but I get WAY too much **** as it is for noise. No way in HELL can I make my car any louder. And on top of that i really don't care about ET or MPH really. Car has been drivable for 1.5 seasons and never been to the track and I am not super itchy to get it up there just yet. I just like cruising with it and going to shows and stuff like that.

So like I said, I can NOT run these straight through style mufflers, so those suggestions are really not needed. Maybe the spintech does suck, maybe it doesn't. I guess I will search for more independtant studies on them.

And I guess i will def take the mufflers out of the headers. thx.

 

the Ultraflo is straight thru but has alot of packing around it. 4inch tube with 6 inch diameter body so its not all that loud

 

My Magnaflow, while it is a"through design", a "bullet" muffler....about 6" round, 16" long (guessing), is NOT loud. At cruise, very quiet, but there. At WOT, it opens up, but still not annoying enough to get a cops attention enough to harass you. It sounds louder in the video than it really is.

 

ha! set off the car alarm, nice

 

i had a dynomax 3" single in single out straight through muffler and it was too quiet, so i PUT spintechs on instead. of course now i have two 3"in/3"out mufflers instead of one, and they are the 105decible proshootout race spintechs, but they deffingitly are wayyyyyyyyy louder and dont restrict the flow anymoer then the dynomax

 

any back to back testing? dyno/track.....

 

no unfortunitly . but it breaks the tires loose just as easy, and will pull from 45 to 120 as easyly. the proshootouts have almost nothing inside them, and with 2 verses one there is no way they are restrictive. also the engine revs up just as fast

 

Kinda interested in how many postes there are in this thread that I started.... Glad to see the help.

Anyways, I guess it goes without saying that I have too much back pressure with the header inserts. There is another problem. Since I had to mod my Mufflex Y pipe to go around my spohn x-member, it had to dip down and has since been dented in pretty bad (flattened from bottoming out).

So that is no longer a 3" in and out on one tube, so that is def hurting the dyno numbers too.

I would love to build a from scratch dual 3" into single 4" and go over the axle and use one of the suggested "through" style mufflers, but I just can't justify the price right now. With that said, let me tell you what I do have.

I DO have a custom built dual setup that I made a while back. Goes off my 2210s, back dimpled a tinny bit to clear the x-member then tucks way up and goes back through a set of dual dynomax bullets. These things do just about NO muffling.... From there, the pipes dump right b4 the axle. Aimed down. You can imagine how loud that is.

So what I was thinking, in the case of trying to find out how bad my current exhaust is, is slap these pipes back on. Cut off the turn downs, and weld on some pipe that will aim the noise out the side, instead of down. Then take it back to the dyno and see what she pulls...........

Any thoughts???

Any and all input is helpfull

Thanks.

-Dennis

Pic of the pipes I am talking about modding a little.





Link to the site with all the pics.

http://www.cardomain.com/ride/782913/21


Thanks again for all the help.

 

well after looking at your cadomain could it not be comeing into power range?

 

you could run that dual setup and run a different muffler there... something like a ultraflo but you will lose alittle clearance from the fatter case design but it will be quieter

but putting pipes over the axle out the back or extend it so it dumps out the sides more will help keep interior noise out....but it will still be very loud

 

how did you decide to build the motor,was it after someone elses specs or was it all your choosings?was the motor "tuned"?

 

Tho motor was built following Trickflows specs for a kit. They sell the heads and cam togeather and say install this on a 350 with a vic. jr and a holley 650 DP and you will get this dyno sheet. They had peak number of 500 HP and 450 TQ (motor)

So I installed it on a 386, did what they said and pulled about 350 HP and TQ at the wheels using a T-56, with this setup.

Yeah, I know I can use a differnt muffler, but I just don't have the $ to spend right now. (student).

Sooo, I figure welding some more pipe will work. Maybe I can use 1/2 of each setup.

Like the first half of the custom, then once it gets back there, put the Y pipe in, go over the axle with the 4" setup and swap the muffler?

I dunno

 

you say you arent worried about et or mph, but yet you talk how dyno #'s are low.
et and mph is the equivalent to more dyno hp.

here is what i run. i bet ive got the one of the most quiet setups for an all motor car.
3" custom y ypipe
4" mufflex
4" bullet muffler in I pipe
necks down to a 3" single in dual out dynomax ultra flow.
its quiet, and has a sweet growl when you step on it.
ive had so many mufflers on my car i cant remember, and this has been the least noisey, and doesnt affect my track times, which in turn would show on the dyno.

 

sounds like a nice setup.

I talk about the dyno cuz it is a nice way to tune the car. I ignore track times and et stuff cuz the car is just about never going to the track. (as of now)

 

run the duals or run the single, either way use a magnaflow muffler. I have true dual 3" dumped before the axle, see it in the true duals sticky. my mufflers are plenty quiet for street operation. The only caveat is that the sound they do make is very low, the sound carries and it sets off car alarms very easily. But again, it is not too loud and it does not resonate inside the car.

 

Boy, did this thread go 180! I wouldn't run the baffles with a muffler. If noise is an issue, try the baffles by themselves and remove the mufflers. It will probably sound more like a NASCAR engine with just the baffles. If you installed the washer and plug (in the photo of the baffle) I'll bet they are a big part of your exhaust restriction/power loss. I would maintain the same tailpipe configuration with or without the baffles/mufflers.

When I get my 84Z back together I am going to install true duals with 1978 Z28 resonators in front of the rear end with tail pipes exiting at the rear of the car. I also have Hooker long tubes and bought baffles which I may or may not use.

Good luck! Keep us posted on what you do....

Woody

 

Stage 20 do you have any pics of your setup?
Thanks,
Kory