close

Privacy guaranteed - Your email is not shared with anyone.

Is 3" too big?

Discussion in 'Car Forum' started by nsb22, Feb 22, 2006.

  1. nsb22

    nsb22 TEAM OAF

    748
    0
    Sep 17, 2003
    cornville!
    I was thinking about putting a 3" exhaust system on my 94 S-10, 4.3 V6. I saw that some people think 3 is too big, and you will loose power. I know that there needs to be some back pressure on the engine, but I didn't think .5" would make that much difference.

    If anyone knows, I would appreciate the help!

    Thanks,
    Ryan
     
  2. spoonhatchcrap

    spoonhatchcrap

    82
    0
    Dec 29, 2005
    nc
    backpressure is a hot rodders myth. you do not need backpressure. the column of exhaust gas needs velocity and to be free of obstructions( ie a meineke exhaust). get a mandrel bent system that is between 2.5-2.75 in. and youll be fine.
     

  3. streeter69

    streeter69 This is Kewl

    450
    0
    Nov 25, 2001
    I like annoying people.
    Makes alot of differance! I have a 4.6 and unless I am at 600 plus HP I am sticking to 2 1/2 pipe.
     
  4. spoonhatchcrap

    spoonhatchcrap

    82
    0
    Dec 29, 2005
    nc
    what makes alot of difference
     
  5. hi speed

    hi speed 10MMGLOCKROCKER

    134
    0
    Feb 7, 2006
    S.C.
    I have a 434ci chevy small block that redlines at 7500rpms. It's topped of with a 350hp fogger system. After numerous pulls at dynacorp, I opted for dual 3" pipes. Trust me when I say, at lower rpms backpressure is needed for torque. This is assuming you dont go down the road at 7000rpms. The 2.25 or 2.5 exhaust will give you power where you use it most. For more info call 18436572!
     
  6. nsb22

    nsb22 TEAM OAF

    748
    0
    Sep 17, 2003
    cornville!
    That doesn't look like a real phone number, and who is it to before I go and call it?

    Thanks

    P.S. I think it came factory with 2.5. I put a Dynomax Bullet on, and it has a nice cackle when it is cold, but as soon as it warms up, there is no character to the exhaust note!

    I had the same type of muffler on my 90 S-10, with no cat and dual 2.25 pipes after the muffler, and Megs exhaust tips. That thing sounded GREAT!!!! It would sound like a semi truck when I manually downshifted the tranny! With that set-up, I did not lose any low-end torque. I think I gained some actually. I live in Iowa, so I didn't have to worry about inspections. This truck gets DOT inspected for transport of certain materials, so I can't do that.
     
  7. mitchshrader

    mitchshrader Deceased

    8,672
    3
    Jun 14, 2005
    Tulsa
    two welded in H bar crossovers.. one fairly close to the front, and one just in front of the mufflers.

    nicer tone on the exhaust. more a growl than a roar, even with loud pipes..
     
  8. nsb22

    nsb22 TEAM OAF

    748
    0
    Sep 17, 2003
    cornville!
    I've done the dual pipes on my last truck. In fact, I was the first one to do them in my area. I just don't really like that look anymore, on any truck! Just one pipe sticking out the factory location for me please!

    Thanks for the tip though!
     
  9. hi speed

    hi speed 10MMGLOCKROCKER

    134
    0
    Feb 7, 2006
    S.C.
    18436572 is the firing order of a V8 Chevy motor. If sound is the wanted result it's all about preference. If getting more than 195-205hp from your 4.3 is your intention then you'll need to do a litlle more than an exhaust swap to tell a real difference. There is no reason to try and get huge amounts of exhaust gas out, if you're not introducing more air/fuel. That being said, a programmer that changes your timing, air/fuel ratio, and the like will benefit from a better exhaust. In your case bigger is not going to be better under any circumstance short of installing a supercharger. Even then back pressure is still your friend.
     
  10. nsb22

    nsb22 TEAM OAF

    748
    0
    Sep 17, 2003
    cornville!
    I've been looking into a decent set of headers for it, just haven't found any I like yet. I've also been wanting a computer chip to throw on it. I don't think anyone makes a plug in programmer for the TBI, but I may be wrong. If you know of one, I would like to know about it.

    I've also been thinking about the Air Raid spacer. My brother put one on his Jeep and he said he could notice the difference.

    I picked up a second job, so I have a little bit of play money, but no time to use it. If you have any links for any products, that would be greatly appreciated!

    I was also playing around with the idea of a charger the other day! How much work would that entail, and would it be worth it?
     
  11. hi speed

    hi speed 10MMGLOCKROCKER

    134
    0
    Feb 7, 2006
    S.C.
    To tell you the truth I have a 2001 blazer with a 4.3 and it's so slow it wont get out of it's own way. I drive it every day and take 2600 mile round trips from texas to S.C. once a month. I have found absolutely nothing that would be cost effective. The supercharging is hit and miss, and would be a retro fit at best. I don't think it would be all that dependable. Maybe a fellow GT member will prove me wrong. I know GMC had the typhoon and cyclone which were supercharged GMC s15's. Seems like they were made in the late eighties and early nineties. Google that and see whatcha get. Where I'm from in S.C. there are no inspection stickers so most just swap in a V8. Kits for this swap are all over the the big E and you'll be eatin mustangs and camaros for mid-mornin snacks. you are right about the plug ins. A superchip is good as well as a few others. Call summit racing or Jegs and talk to a tech guy. Summit and jegs are neck and neck with customer service, selection and knowledge. Buy from the one that is cheapest for the stufff you are getting. There are a million sites devoted to your truck and these guys can help you so much more than I. If you go the V8 route though, drop me a line couse I've been racing them for 18 years and counting. My all alluminum 434 w/o NOS is 725HP and is street legal. Wipers,tag, in dash dvd, power windows even. Pontiac WS6.
     
  12. Syclone538

    Syclone538

    2,086
    1
    Jan 8, 2006
    You never want any backpressure in a four stroke. With too big of an exhaust at low rpm there is not enough exhaust flow and it slows way down creating backpressure. Some people see this and say, “this 4” pipe on a 3 liter slowed it down, so you must need backpressure.” You never want any backpressure in a four stroke.

    3” on a 4.3 is above ideal, but I doubt it will hurt much. ATR makes a 3” cat back that might fit your truck. I’m not sure exactly how a non-turbo exhaust is set up.

    It would not be worth it to get a turbo or supercharger, if you want that much more power just go with a small block.

    With 8.3 compression pistons (stronger then stock, but not forged), 15 lbs of intercooled boost and strong main caps, we get ~300 hp and ~375 tq. But it would be nowhere near economical compared to just using a 350.

    I don’t have any n/a links, but if you want a ton of turbo links just let me know.

    I believe you have L35 heads, if so, check to see if anyone makes a lower intake that will let you use vortec heads and still use your upper intake.
     
  13. hi speed

    hi speed 10MMGLOCKROCKER

    134
    0
    Feb 7, 2006
    S.C.
    Not a challenge,not for the sake of argument, just a question.. Why did a 4" exhaust with the same 2 chamber mufflers(obviously with different inlet/outlet) set a 46.3 hp decrease and 51 yes 51 ftlbtq decrease under the 3"? My car also hit it's peaks at a signifcantly lower rpm. As a rule high rpm motors do like to breathe but for an engine like a 4.3 that redlines below 5grand it does no good. After hangin around the dyno shop for a couple of weeks so I could get free pulls, I've seen no gain in torque for 6 or 4 cylinders with any exhaust modification with the exception of non-naturally aspirated engines. HP does not pull you off the line and has no real benefit over TQ increases for daily drivers. A truck needs it low where you can use it. Light pole to light pole TQ is key. A free flowing exhaust even if what you say is true is going to produce power higher in the rpm range and in return take longer to get to from a stop. City streets are stop and go and to say different means a whole new ball game as now you'll be talking drag truck for the strip.
     
  14. Syclone538

    Syclone538

    2,086
    1
    Jan 8, 2006
    Sorry if I came across kinda short. You obviously know about making power if you have a car that runs 10.20s. It just bugs me when people say you need backpressure. It just goes agenst everything about making power. You want the exhaust out and the air/fuel mixture in as fast and with as little restriction as possible. Having too big of an exhaust doesn’t take away power because you need backpressure, it takes away power because too big of an exhaust creates backpressure. You lose velocity and momentum and the exhaust gas cools off and starts condensing before reaching the end of the exhaust compounding the problem. If you are staying at a set rpm this doesn’t hurt anything, but when trying to accelerate your engine produces more exhaust and it has to follow the cooler slower moving exhaust and that creates backpressure. I hope that made sence.

    You are saying that your car hit it's hp and tq peaks at a lower rpm with the larger pipe? I don't know, that doesn't make any sence to me and it goes agenst everything I just said.

    Pretty much agree with everything, but as long as you don't go too big to the point of losing tq, if you free up the exhaust some and have the same tq and a little more hp, that is a good thing.
     
  15. hi speed

    hi speed 10MMGLOCKROCKER

    134
    0
    Feb 7, 2006
    S.C.
    Produces peak power at lower rpm's with smaller pipes. 10.20 no juice. Nitrous has only been used doing things that are not wise to state in public forums. I can't get the local track to let me run a NT/PT like they do in the south. Don't wan't to shoot myself in the foot by having people know exactly what the car runs. I'd never be able to afford my other past time, shooting.
     
  16. Syclone538

    Syclone538

    2,086
    1
    Jan 8, 2006
    Ok, I just misunderstood you earlier. Yeah that's the way it should be. Smaller exhaust pipes work better at lower rpm and less exhaust gas. Larger pipes work better at higher rpm with more exhaust gas.

    edit
    Just think about cams, it’s the same thing. Get a giant cam that opens a big hole and your car idles like crap because you have so little velocity/momentum. It runs good up top because with the increased airflow the velocity comes back up.

    I kinda feel I should say that I do not build race engines or anything like that, its just a hobby for me and there are a lot of people that know a lot more then me about this stuff.
     
  17. gixxer11

    gixxer11 bbrrraaapppppp!

    257
    0
    Jan 11, 2005
    in the garage
    All of my experience with bikes has led me to belive a smaller diameter will help with throttle response, i.e. more velocity at lower rpms (same with the intake). Not really proven on a dyno, but seat of the pants. With the very mild state of tune, it is not nessacary. Besides with stock exhaust manifold, intake, cams, head porting, etc. it probably won't change much. And with that, I agree 100% with hi speed. Internal combustion is the same big or small, they're all air-pumps with fuel. It all needs to work together.
     
  18. I'm not going to get into the exhuast debate, as there are apparently alot of people very passionate in their beliefs about backpressure.

    I'll just say this......

    I wouldn't dump alot of money into that 4.3.

    You can do the exhuast, headers, intake spacer, injectors, CIA, and so on, and you're still not going to see much of a differece.........you're ESPECIALLY not going to see a $3-500 differece that you'll have into it.

    I think you're throwing your money down the tubes. Just enjoy some good sounding mufflers, put decent gas in it, and enjoy.

    The 2.5in. exhuast that you have no is just fine.

    Been there, done that.
     
  19. Syclone538

    Syclone538

    2,086
    1
    Jan 8, 2006
    Agreed, but if you are going to I would say vortec heads would be the most cost effective way of gaining some power. Edelbrock 2114 comes to mind, but not sure if that’s the right one or not.
     
  20. hi speed

    hi speed 10MMGLOCKROCKER

    134
    0
    Feb 7, 2006
    S.C.
    +1