exhaust

[carnut4real]

I want to run 3 inch exhaust off my headers and dump off behind the cab,but I'm not having any luck finding anybody that sells a 3-inch for a c10 anyone know of anyone who sells a kit.I also need to do something different with my stock clutch fan and I've seen people saying they got rid of the electric fans and went back to a clutch fan and so on and so on, but my new engine is still running warm with no thermostat, so I figure good start is to open up the exhaust, that may do it but looking for feedback on the fan also

[y5mgisi]

Shouldnt really need much of a kit should you? Off the headers, straight back, into muffs and turn downs. And bigger exhaust isnt going to make the truck not over heat.

[carnut4real]

I have to disagree, the quicker you can get the exhaust out the cooler the engine will run. it's important to let it breath both incoming and out going. I had success with motor homes, and my big block mopars doing just that. My truck currently has a dinky 2.25 full length exhaust choking it

[MalibuSSwagon]

Are you using the stock shroud with the fan? Not going to cool real well without the shroud.

Electric fans are great btw, I used a set from a 95ish Windstar and they keep the truck cool on the hottest days.

[carnut4real]

I am running the stock shroud. I had to modify it to fit the new aluminum radiator, so I'd be better off without it ? I'm going to pickup a flex a lite 18" pusher fan to put on front of the radiator also .

[donut]

Exhaust kit, behind the cab, 3"... Walk through the parts store and look at the exhaust parts. Straight pipe, muffler, turn-down, x2. Running warm with no thermostat, have you tried it with a thermostat? Have you checked temp or are you relying on the factory gauge?

No idea what you have or what's been done before. Basic info would help.

[cadillac_al]

Engines don't run right without a thermostat. You need a thermostat and a shroud. I don't think any of my trucks have clutch fans, just solid fans. I have a little flex fan and no shroud cooling my 400sbc in an Impala and it never overheats. I'm not a fan of 3" exhaust unless there is no room for real duals. If you have to have a 3" I'm sure the early 80's Camaro headers and Y pipe should fit.

[donut]

Ah, just assumed it was a 3" dual. Seems that's what all the cool kids want.
3" single, best bet may be to hit an exhaust shop and have one made. Had a single 3" on an Impala wagon, exhaust shop reworked the factory Y pipe. This was off factory manifolds so obviously yours would be different.

[carnut4real]

just to clarify I just installed of 465 horsepower small block 408. don't ask me why? I'm 52 years old an I guess I wanted to get to the Home Depot faster

[carnut4real]

I did remove thermostat in a helped my intentions are to put a thermostat back in once I get it so around at a decent temperature. I installed a two-core aluminum radiator, and I'm going to put an electric pusher fan on the front. It has headers with duel two and a quarter inch exhaust all the way back

[carnut4real]

Sorry for the misuse of words and spelling, as I'm talking into my phone

[dieseldawg142]

if you have to, make a shroud out of sheet metal, you'll loose a lot of effectiveness without it, & a t-stat.
i dont have 465 horse in my bb, but it hauls 15k around the mountains, 190 t-stat., 3 core alum rad, factory shroud & c. fan, never overheats. another thing good for a couple degrees, (some swear by them, some swear at them) a good oil cooler.
i dont think a 3" exhaust will help you, after i put mine in, only thing i noticed was the floorboards started getting warmer & the NOISE! if you dump behind the cab, you will go deaf, irregardless of what muff. you use. 3 inchers resonate like you wouldn't belive. started with FM 40's, then magnaflows, FM delta 60's, currently running FM bb 70's. notice there getting bigger & quieter, the first 3 would set off car alarms just from the crack of firing it up. after i finally sound deadened my cab, i'm now happy with a 3" exhaust.

[carnut4real]

Thanks dieseldawg good feedback

[NJ C10 Guy]

Originally Posted by carnut4real

I want to run 3 inch exhaust off my headers and dump off behind the cab,but I'm not having any luck finding anybody that sells a 3-inch for a c10 anyone know of anyone who sells a kit.I also need to do something different with my stock clutch fan and I've seen people saying they got rid of the electric fans and went back to a clutch fan and so on and so on, but my new engine is still running warm with no thermostat, so I figure good start is to open up the exhaust, that may do it but looking for feedback on the fan also

My reply is a little late, so not sure if you did anything or not. I have the exact setup you are talking about. Personally I'm not a huge fan. I'm actually looking to go with a catback and have it run out of the rear. I have straight pipes coming off my headers, right into flowmaster mufflers, with a 3" turndown just past the cab.

[Kinze]

Stainless works makes a dual 3in. mandrel bent stainless exhaust system for these trucks.

[piecesparts]

So, if I read this right, you put in a new engine and it is running hot. You want to put on shorter exhaust pipes to help cool it. You already put in a new aluminum core radiator and are still running a stock clutch fan. There are some things to think about in what you have and what you can do to improve. Just my .02 worth.

What are running for timing on the engine? That will generate more heat than anything else, if it is too retarded. The aluminum radiator may be a little restrictive for whatever size engine you are running. The exhaust will work very well on your truck if you run it off of the headers and take it all the way to the back with a smaller size than 3" pipe. The principal of exhaust sweeping the cylinders is accomplished by the exhaust cooling and creating a vacuum effect on the engine. Your fan shroud may be your biggest culprit in your loss of cooling, not to mention the removal of the T/stat. The reason I say this, is coming from my time dealing with a company called "Be Cool".

The first thing is to control the water in your engine and let it actually absorb the heat being generated, so a T/stat will help in that arena. This is where a little restriction is a good thing. Also, is your new radiator one that was built by a reputable company, or is it one that came from another vehicle? The headers is a good thing, but build the rest of the system for efficiency and performance. Remove the exhaust gases and not create a reversionary effect that will hamper the system's performance.

The pusher fan may work, but in many cases a pusher fan will become somewhat of a air flow restriction and may not help. A puller fan is more efficient and will move more air than a pusher. The fan clutch may be defective and if you fan blades are NOT positioned right in the shroud, they could be moving the air ineffectively.

I say all of this, since I have built my 84 GMC with a 385 stroker engine, dual electric fans, headers--2 1/2" exhaust dual , aluminum radiator (Four core), and a 700R4 tranny. I have no issue with cooling and I run a 180 degree T/stat.

I see so many well built rods out there that are sitting on the side of the road, puking the green stuff, due to the build ending before the important part is done. Now that you have gone the first mile, go into this with a little research and be successful.

[Oregoon]

I agree with the poster above. And I'll add my .02 cents...

I had a 392 IH in a Travelall, and after a rebuild, it behaved much like yours--warming right up and getting hotter by the minute. I tried playing with timing, flushing the cooling system, replacing the water-pump, etc. Finally, I pulled a 3-row radiator out of another truck, and if anything, it ran hotter...

Then I checked my plugs and they were just barely ashy, so I borrowed a carb from a friend, and she cooled right down. After experimenting with several sizes of jets, all was well.

Food for thought.

[SCOTI]

Originally Posted by carnut4real

just to clarify I just installed of 465 horsepower small block 408. don't ask me why? I'm 52 years old an I guess I wanted to get to the Home Depot faster

Nobody asked..... Who built the motor? Did they make sure the heads have the correct steam holes & head gaskets? Those are the top reasons 400's have cooling related issues.

[Mike Bradbury]

I have Ram horn manifolds on my SBC with two 90* bends heading into side pipes and then straight out on the side of the bed and dumps in front of the rear tires. Not too noisy but just enough rumble to be respected at a stop light. I have noticed that I have the opposite effect where my stat is many time not opening because the engine is always running at or below 180*.



Hear is a video of the sound;








.

[hatzie]

There's some of the black arts involved in exhaust design. I remember reading in Car Craft back 30 years or so ago that it's possible to go too big on exhaust pipes. The 350 Smallblock seemed to like 2.25" to 2.5" duals and larger actually cost some HP.

Based on personal experience... Normally Aspirated Diesel HP seems to plateau when there's enough exhaust pipe diameter. Bigger just costs you money and space for larger pipes. OTOH... When you exceed optimal pipe size on a Turbodiesel you can overspeed the turbine under the right circumstances. Too large pipe size can slightly shift your boost curve as well.

Normally aspirated Gasoline engines seem to have a HP to pipe size bell shaped curve HP actually drops once you exceed the optimal pipe size.
http://www.hotrod.com/how-to/engine/...-inch-exhaust/

X and H pipes seem to make a difference as well but, since I have mostly Turbodiesels in my fleet, I don't understand those dynamics very well. The CUCV is mostly stock and the Impala is a "drive it as is" car.

[andrewmp6]

Which water pump you got on it?If you have the wrong rotation water pump it won't cool right and run hot.And running a exhaust that big when its not needed will kill back pressure and have less torque to it.

[bbbc10]

I have 3" exhaust on my stock 350 an it runs fine an btw I have a steel fan on mine that pulls air into the engine bay I had a aluminum fan but it blew into pieces one day as my dad was leaning over it but u can run stock ls1 fans also an I would put a thermostat in it

[scottybaccus]

You have no idea how well your radiator is working if you have no thermostat. Part of it's job is to make sure coolant stays in the core long enough to cool down. Taking it out is a mistake.
Have you checked your timing? And I don't care what you think it is, if you haven't verified TDC on your pointer, and applied a timing tape or used a dial-back light, you can't be sure. Whatever it is, back it down 5-10 degrees and see how it affects your temps.
There is something wrong when you can't get the OE parts to run cool. 2.25" pipes, quiet mufflers, catalytic converters, clutch fans and skinny radiators worked fine when it was new, and shouldn't be an issue, unless you doubled horsepower.