I have purchased an 89 Formula 350 and am putting am looking for an exhaust system to put on it. I have had a 12 sec. S-10 before I sold it I ended up trying 3 sets of headers and 4 different muffler setups, and at $300 for headers, $200 for mufflers, and $200 install it got expencive.

So this time I would like to do this exhaust ONCE! I am totally new to y-pipes and have been trying to read up on them(some bad, some better) what about mufflex 4"??

I know i will be getting Hooker Supercomps #2210 1 3/4" LT headers, but what would everyone recommend for a setup after the headers that will let me eventually run mid 12's naturally aspirated....Im open to single(with y-pipe) or duals....and it will be street driven....

Just want some advise with people who have actual cars running 12s NA.....

Thanks

 

Well, I don't run 12's, but I think that a 4" system is too big.

Go with SLP headers and any 3" cat-back and you should be fine.
As long as the y-pipe is 3", that's what you want. (SLP, Hooker, and Hedman are the ones I can think of)

 

anyone have experience with this:

MUFTPIYC
3" Off Hooker Long Tube Offroad Y Pipe For 82-92 Fbody
250.00



"The Mufflex cat back exhaust systems are simply the highest flowing on the market. They feature 4 inch mandrel bent aluminized tubing which empties into a Flowmaster Race muffler with a single turned down hidden tip. The sound quality is simply amazing and puts other systems to shame. These systems are intended to be installed on modified cars that require the highest exhaust performance.

 

Do you have to stay smog legal. 4" is not too big for a 12 second car. My car runs 12.6's on radials, and I think that the best exhaust for a decent 350 is dual 2 1/2" into an X pipe into 2 2 1/2" bullet mufflers. That is the setup I run.

 

FWIW, I ran the time in my sig with SLP 1 3/4" shorties, gutted cat, and 3" Flowmaster cat back. I suspect the Flowmaster is costing me some power so I'll be going with a Dynomax or Spintech real soon. There are other people that run 12's NA with just a 3" cat back....no need for duals or 4" catbacks. Plenty of people run in the 10's with a 3" exhaust.

I think the biggest gain will be going from shorty headers to long tubes with a good mandrel bent 3" y pipe....even the SLP y pipe is not a true 3" system.

 

Thanks for the input.... I would love to do the X-pipe(just to do it) do you have any pics??

 

I honestly am leaning towards the mufflex single 3" system for Hooker LT's. Since people run 12s and faster with a single 3"
I might as well go with something easy with no/less fab-work.

now to find a sound bite, Ill search after work...

should look like this....right(I know its not the same part number)?

 

here is the only pic they put up thats the actual part # I want

 

You are gonna need a 3-1/2" exhaust - which Mufflex makes (I have the 3-1/2", btw). 3" starts becoming restrictive over 325hp or so.

 

Exactly. Just because people run 12's with single 3" doesnt mean its not a restriction.

 

If you are not worried about ground clearance AND you don't plan to EVER need another type of tranny crossmember (Spohn, SPD, etc.) AND emissions aren't a concern - then the LT's are a good choice along with Mufflex's 3.5" catback. You can expect their TPI-Y pipe to NOT bolt-up. Those who did manage to bolt it up are in a very very small minority.

If you do need more ground clearance or you plan to run a different tranny crossmember or emissions are a concern - then the SLP 1-3/4" shorties are the next best headers.

Tim

 

Spohn or someone else needs to step up to the plate and make a crossmember like the one deadbird made. For those that don't know he hacked up his stocker and made two upside down U's on either side of the tranny so he could run duels and keep good ground clearance, He does have a T-5 though so I don't know if it is possible with a 700-r4. I am going to attemp to fab somthing up for an auto, mabee out of two seperate pieces of tubing.

 

True, but it also means you don't need a 4" exhaust to run 12s either.

 

The crossmember is substantially smaller widthwise on automatic equipped 3rdgen cars. I got under my car and looked and it would be a stretch, to say the least, to think that it would be possible to get two pipes up there.

 

I will never understand that logic. If I can get a few tenths anywhere I am willing to do it.

 

Just FYI, but 4in exhaust is OVERKILL. My a friend of mine has an '02 SS Camaro with an MTI 422ci stroker LS-1. He lost 12hp and 20 ft. lbs torque when he used the 4in. mufflex system. And that was on the rear wheel dyno! He switched back to his 3in. Borla system. 3in is plenty enough exhaust to run 10's N/A.

 

He lost that much peak?

 

Not true. T-5 and auto use the same x-member. The lack of space on an auto is from the size of the trans itself. There is not nearly as much room between the trans and the frame rails. It could be done but, not easily and you would definatly need some heat shields.

 

I have never seen a car run 10's N/A with 3" exhaust ...I have however seen a few nitrous powered cars do it. It really doesn't make since that a 422" motor probably making 600HP would benefit on a dyno from smaller exhaust. I could see him benefiting at the track but not on a dyno.

MAYBE just maybe I'm talking out my *** right now ...I'm pretty tired but tell me if this makes sense and correct me where I'm wrong..... At the track the smaller exhaust could be bringing his peak HP/TQ down in the RPM range ...So like lets say his car is geared and stalled properly to work with the lower RPM range of his motor. Now he bolts on 4" exhaust this brings his peak HP/TQ up in the RPM range now his car is a little off... Motor makes more power but the rest of the drivetrain is designed to operate at a lower RPM. Thus he runs a slower ET while still making more HP/TQ

 

another reason why borla is better

 

Two things to keep in mind ...

1) Guys are using Borla because of the adjustable plates and they are essentially running NO muffler at the track because they are using the open plate. A similar flow can be obtained via using a muffler with a straight through design like the magnaflow or the Dynomax ultraflo.

2) Although backpressure is bad ... VELOCITY is good. Why? If you understand cam dynamics then it all makes sense. During the overlap period the exhaust can essentially help suck in the next incoming air charge (since both valves are open). Velocity allows this to happen. If you are running an exhaust that is too large then the velocity will be very slow and you won't be able to truly obtain the benefits of overlap.

Tim

 

Sorry Guys I was gone for a few days out of state..heres some more info...

I have no emissions to work around.

I am thinking of the 3" over 3.5" soley for noise reduction.

I wouldnt use the muffler the system comes with, I would use an Edelbrock Race Series 3" Center/Center. I had dual 3" on my old S-10 with these mufflers and it was too loud so I took them off and put on a set of Flowmaster Big Block II mufflers.

I am hoping that only 1 wouldnt be quite as loud??

 

I just got done reading about this pressure wave tuneing . It says that these effects are minimal with cams haveing less than 40 deg overlap . BUt can cause up to 3 times the effect of the cylinder going down the bore . But even if the exaust is too big .....if you have a way to add a terminator box ( they say it has to be 8 times the volume of the cylinder ..but 11-15 is better ) . I am no expert ....I just read it ...and thought it was relivent...so I figured I'd pass it on . So I would assume you can;t have an exaust to big ....if its tuned ?

 

I've ran in the very low 12's with my exhaust setup. Hedman full length headers, 2 1/2 inch pipe coming off the headers w/cutouts just have the headers. 2 1/2 pipes y into a single 3in Flowmaster. Not too loud for street driving and I just open the cutouts at the track for maximum performance. Its a good setup but I'm going to make an attempt at dual 3in. soon.

http://www.geocities.com/jbenge/exhaust.html

 

I run 3" duals on my 86 Z28, but it is very loud, sets off car alarms!! I also run headmans on that with 3" all the way back and dump under the rear end.

Since I started this thread way back when, Things have changed , I have decided to go back to college full time for my Bachelors degree, my wife decided she wants breast implants. So that leaves me with $0. GRRR.....

Oh you want to know something else thats stupid? My 89 (100% stock) Formula 350 has SFCs and the 86 Z28 doesnt

 

A little confused here, SweetS10.?.?.? She decided she wants them....... or YOU decided YOU want them?

 

She wants em, I barely get to the computer anymore. Seriously I tell her to stop making me look at ***** online, lol

 

Way off-topic, but a wife that wants implants is looking to leave.

 

 

just don't try and use the slps if you have angle plug heads....you won't be able to get 1 plug in on each side of the car....