What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

3" or 2 1/2?

shaun89

shaun89

1/2 ton status
Joined
Aug 7, 2005
Posts
1,939
Reaction score
1
Location
center of CT..ish
im getting an exhaust put on my truck and im gonna put normal universal cats on it and 60 series race mufflers,with no equalizing pipe,and its dumping before the axle,now i want it to sound good but have enough back pressure to run healthy,and not loose any torgue so..anyone have any experience with this? o ya its a stock 350 out of an 88 caprice. thanks guys
 
stock 350, i'd run 2.25 pipe and that equalizing pipe, it'll still sound good and have good back pressure.
 
yea u really need the equalizer. id run 2.5" pipes so it would be perfect even if u end up doing mods.
 
I run dual 3" off the headers into an x-pipe with dual 4" coming out into 6" tips. No mufflers. enough backpressure to make the 454 happy and sounds awesome.
 
A single 3" exhaust will give you the most amount of torque from a stock 350 engine.
 
2.5" with an crossover pipe (an x-pipe if you can fit it) if you plan on mods, or 2.25" if you plan on leaving it stock.
 
4X4HIGH said:
A single 3" exhaust will give you the most amount of torque from a stock 350 engine.
Click to expand...
Interesting. This building upon the specs of the stock 350 as is already built for torque as opposed to high horsepower. So without the scavenging effects of the crossover, the combustion tends to be lazy, promoting torque?
 
back pressure doesn't equal torque, velocity does.

It's a fine line, go with what is known to work. Too large and you lose power because the exhaust is no longer efficient, not because there isn't enough backpressure.

Go read some exhaust articles (especially by David Vizard) if that concept is foreign.
 
trailblazr81 said:
Are you running manifolds, shorty, or full length headers?
Click to expand...
Stock manifolds with smooth bend pipe to Flowmaster Y pipe, then 3" pipe to hi-flow cat and magnaflow muffler. Way better than stock setup. I would like to go with shorty headers IF I can get bolts that don't back off every three minutes!!
 
Look in Summit or Jegs for locking header bolts. Seems on my aluminum head 383 every month or so I need to retighten mine or I start to notice an exhaust leak and find Im missing a couple. Now Ive been reading a few engine building books and they seem to agree that you want full length headers and dual 3" pipes to make the most power, and you want the H pipe in a certain place (hot spot in exhaust). I know this is not always possible with emissions, etc. but stay with the same size pipe as your collector diameter of header. I have always gone this route running 3" pipes when using full length headers, and 2.5" when stuck with manifolds or Y into single 3". Alot of people claim big pipes hurt low end, and alot say since your header collectors are 3" after that it doesnt matter. Whatever you do youll make more power than stock, and larger pipes look sick, and usually sound better IMO. And usually if you loose low end you'll make up for it in HP, unless your building a crawler.
 
roadnotca said:
Ain't there no old timey Hot Rodders in here? :haha:
http://www.stage8.com/
Click to expand...
I used the stage 8 locking bolts before. It was a bust. The bolts would back off anyway with enough force to actually round off the special half moon cut washers and keep going! There has got to be something better.
 
88$PIT said:
I used the stage 8 locking bolts before. It was a bust. The bolts would back off anyway with enough force to actually round off the special half moon cut washers and keep going! There has got to be something better.
Click to expand...
All those years and I never used them myself. To bad, just another hype product.:(
 
dont use paper header gaskets. use regular old exhaust manifold gaskets. tighten em once, and forget about em.
 
took my engine builders advice and haven't had any leaks. bolt on the headers. then run the engine till its at operating temperature. shut it off and torque down the header bolts. Never had a leak until the other weekend when my shackle bolt hit the collector flange and tweaked everything. ran it several years like that though.

I would run 2.25" pipe with a crossover if possible. but your question was 2.5 vs. 3. so run the 2.5" if thats the only choices.
 
You must log in or register to reply here.

Latest Posts

Top Bottom