Is 3" too big? [Archive] - Glock Talk

PDA

View Full Version : Is 3" too big?


nsb22
02-22-2006, 19:59
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

spoonhatchcrap
02-22-2006, 20:29
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.

streeter69
02-22-2006, 20:32
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.

spoonhatchcrap
02-22-2006, 20:36
Originally posted by streeter69
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.

what makes alot of difference

hi speed
02-22-2006, 20:44
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!

nsb22
02-22-2006, 21:13
Originally posted by hi speed
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!

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.

mitchshrader
02-22-2006, 21:14
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..

nsb22
02-22-2006, 21:15
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!

hi speed
02-22-2006, 21:26
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.

nsb22
02-22-2006, 21:31
Originally posted by hi speed
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.

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?

hi speed
02-22-2006, 21:53
Originally posted by nsb22
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? 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.

Syclone538
02-23-2006, 01:20
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.

hi speed
02-23-2006, 03:27
Originally posted by Syclone538
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. 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.

Syclone538
02-23-2006, 04:06
Originally posted by hi speed
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"?

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.

Originally posted by hi speed
My car also hit it's peaks at a signifcantly lower rpm.

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.

Originally posted by hi speed
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.

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.

hi speed
02-23-2006, 04:27
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.

Syclone538
02-23-2006, 04:33
Originally posted by hi speed
Produces peak power at lower rpm's with smaller pipes.

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.

gixxer11
02-23-2006, 07:01
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.

Ktmexperiment
02-25-2006, 12:38
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.

Syclone538
02-25-2006, 13:01
Originally posted by Ktmexperiment
...
I wouldn't dump alot of money into that 4.3.
...
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.

hi speed
02-25-2006, 13:36
Originally posted by Ktmexperiment
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. +1

nsb22
02-25-2006, 14:50
Originally posted by Ktmexperiment
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.

Thanks. I suppose I could do what I was thinkingabout the other day!

Take a 383 and complete computer system out of a new GM truck, drop her in mine, and have some serious fun confusing people!

Oh look, there is a little S-10, isn't it so cute! What the hell? That thing just beat the pants off that (insert car name here)! That thing is freekin cool!


It would work, I would just have to find a donor truck first!

hi speed
02-25-2006, 15:36
Originally posted by nsb22
Thanks. I suppose I could do what I was thinkingabout the other day!

Take a 383 and complete computer system out of a new GM truck, drop her in mine, and have some serious fun confusing people!

Oh look, there is a little S-10, isn't it so cute! What the hell? That thing just beat the pants off that (insert car name here)! That thing is freekin cool!


It would work, I would just have to find a donor truck first! A sleeper! Damn right doggie! Now your'e getting it. I love it when wanna be rollers pull up and I've got WS6 out on the weekend. It takes a motor the size of theirs to start mine. The zz4 crate motor from GM performance is a bad a** engine. Auto center in dallas TX has a great inventory and I've delt with them a few times. Keep on keepin on my freind. It's all about love for the auto. Try to meet new people and get all of their opinions. Then find a middle ground and go for it. It's better than blowing money on drugs and **** like that. If you ever need any help gimme a hollar!

hi speed
02-25-2006, 15:52
One other thing, It's not a bad Idea to keep the truck stock and buy a "donor" and just fix it up. Gas is a burden nobody can break free of. Something that can get'er done on the weekend is more frugal than a multi-tasking race ride. I assure that things as simple as u-joints can make you late for work. Truly fast cars rarely ever see the daily grind of bumper to bumper traffic. If I would have saved the money from the post high school freedom of what I want, and saved, I would have gone fast a whole lot sooner. Remember, When owners of really fast cars see an idiot with nothing more than a loud exhaust pull up, they don't think your stuffs the ****, they think hmmm;"I bet I could have made it fast instead of annoying". Good luck Hi Speed!;)

nsb22
02-25-2006, 19:08
Originally posted by hi speed
One other thing, It's not a bad Idea to keep the truck stock and buy a "donor" and just fix it up. Gas is a burden nobody can break free of. Something that can get'er done on the weekend is more frugal than a multi-tasking race ride. I assure that things as simple as u-joints can make you late for work. Truly fast cars rarely ever see the daily grind of bumper to bumper traffic. If I would have saved the money from the post high school freedom of what I want, and saved, I would have gone fast a whole lot sooner. Remember, When owners of really fast cars see an idiot with nothing more than a loud exhaust pull up, they don't think your stuffs the ****, they think hmmm;"I bet I could have made it fast instead of annoying". Good luck Hi Speed!;)

That is just funny! When I do end up making a sleeper, I figured on getting a second truck. That way I could keep it hidden while working on it, as to prevent certain family members from wanting to help. They always try to make it their own, when it is MINE!!!

Thanks,

45acp4me
02-26-2006, 09:50
Originally posted by Ktmexperiment


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.

Bingo! A full 3" straight through exhaust will rob low end torque and the gains up top won't justify the cost on that motor. Only if the motor is getting a blower or a big shot of nitrous would a 3" exhaust even start to be helpful.

Asha'man
02-26-2006, 22:25
3" is way huge on a n/a setup, unless it really is a high hp motor like a big inch V8 or something. I have 3" on my 2.3, but forced induction is a different story. Were I you, I would keep the stock exhaust on your truck and just weld in a muffler.

Brian

Ktmexperiment
02-27-2006, 04:16
The engine swap idea is cool, only if you have the time and money.

I hate to keep raining on your parade, but I'd hate to see you go through all the headaches, and late night have fiddling with that stuff.

I've considered doing the 350 swap on my Chevy 1500. The 4.3 is kinda week on a fullsize truck. It would technically bolt right up, but there's some many other "little" things that come up when i motor is pulled for the first time.

You'll have to get the right wiring harness, and ECU. In addition to that, you'll always have some PIA nuts and bolts here and there, and sometimes some unexpected small fitment issues.
I don't know much about the 383 motor, but I do know that since you're talking about an S10, you may be looking at an all new drive-line, altogether. We're talking everything from the tranny, to the transfer case (if it's 4wd) to the rear end and axles. That could get INSANE expensive, even with a donor truck.

I've weighed the cost of doing it to mine, and all I"d need is just the motor and electronics. However, it could still end up being just as much as if I traded my truck for one with the motor I want already in it.


I guess my days of hotrodding are over, so to each his own.

I just want you to be aware that these kinda projects can end up "nickle and diming" you like crazy in the end.

nsb22
02-27-2006, 18:40
Originally posted by Ktmexperiment
The engine swap idea is cool, only if you have the time and money.

I hate to keep raining on your parade, but I'd hate to see you go through all the headaches, and late night have fiddling with that stuff.

I've considered doing the 350 swap on my Chevy 1500. The 4.3 is kinda week on a fullsize truck. It would technically bolt right up, but there's some many other "little" things that come up when i motor is pulled for the first time.

You'll have to get the right wiring harness, and ECU. In addition to that, you'll always have some PIA nuts and bolts here and there, and sometimes some unexpected small fitment issues.
I don't know much about the 383 motor, but I do know that since you're talking about an S10, you may be looking at an all new drive-line, altogether. We're talking everything from the tranny, to the transfer case (if it's 4wd) to the rear end and axles. That could get INSANE expensive, even with a donor truck.


Technically, I should be able to use the tranny currently in the truck I have. A rear end swap was already planned, probably a 9" from a Mustang.

Engine would come out of a LIGHTLY wrecked truck, therefore, I would have the correct harness and ECU.


Now, this won't happen unless I win the lottery, so we have nothing to worry about!

Thanks