What would be the horsepower difference between longtubes and shorttubes on a otherwise identical combo? Are shorties any easier to install? I am wondering if the cost and installation arent ustified by hp.... any opinions??

 

why not just get LTs??? unless have emission trouble in yout state... maybe only a few more hp on stock motor, but once get into bigger things.. you see bigger gains...

-cory-

 

Longtubes vs. shorties on the top end, shorties usually make a tad more power, at least on a higher revving engine. The scavenging effects of longtubes at lower rpms, though, is a lot better than shorties. The reason so many people get longtubes is because it's one of the few modifications you can do that will increase low end power significantly while also helping out on top. Longtubes may have fitment and clearance issues but they also give you more of that low end punch that is a very big issue on street driven cars. Shorties won't have the same effect, although they're still quite a bit better than the stock manifolds. If you're just looking for a little more power and a more pronounced exhaust note, you should just do shorties- plus they're emissions legal in every state, but if you want the most power you can get you might as well get longtubes now, especially if you'll be swapping cams or doing head work.

 

LT's are good for about 20-30 HP. Great gains with them, and they also sound a hell of a lot better!

 

I always thought it was the other way around, not saying you're wrong but so are the lts better down low and shorties up high?

Ive always been told that shorties and mid are good low and lts are good up high.

 

Overall, LT's are a bigger power gain no matter what application they are on Long tubes kick ***!

 

Unfortunately there's a lot of misconceptions when it comes to modifying engines. It's hard to explain, but exhaust tubes are a lot like intake runners. I won't go into the theory, but here's the results

Size (Cross-sectional area):

Large= flow (hp)
Small= velocity (tq)

Length:

Short= flow
Long= velocity

With that knowledge, you can pretty much see why there aren't really any aftermarket intake manifolds for LT1s, since the runners are only a few inches long, and porting them a little doesn't require replacement. The runners on a TPI engine, however, are very long, and although they do great for low end torque, they limit top end power quite a bit.

Most available shorties come in 1 & 5/8 sizes, vs. 1 & 3/4 for longtubes. You can see how each is a compromise, since the shorties give up some cross-sectional area to promote velocity at low rpms, where the longtubes go larger to promote flow on top. That's really a simple explanation, if you check out the advanced section there's some detailed information. But basically, longtubes are the better choice for power on practically every engine. You'll see longtubes on wheelstanding cars the same as you will on street engines.

 

"LT's are good for about 20-30 HP"

come on...quit listing manufacturers advertised gains.

i have yet to see LTs dyno any more then 20hp on even cammed motors, let alone 30.

maybe if you did LTs, true duals and a dyno tune (which is helping alot more things than just the addition of the headers) you could possibly see 30hp...

most dyno tests i've seen in the past 5yrs of watching mods to 4th gens on here have been more like 15hp with LTs

 

However, you have an entirely different set of issues when dealing with a street car...


Shorties can be purchased that are carb compliant, (legal), install more easily (in general), and provide a decent bang for the buck. On a stock or mostly stock car that sees mostly street duty you can obtain better gas mileage, better torque, and better top end performance over the stock exhaust and still pass inspection without a hassle.

I used shorties for three years until I did the stroker which required longtubes for proper performance.

Basically if you plan or or have shorties, cat back, cai, shifter, gears, torque converter/shift kit, tranny cooler, and even if you do a mild cam and/or port job and 1.6 rollers, shorties are fine. Sure you might pick up an extra .05 in the quarter mile with long tubes, but the hassle factor is usually much higher.

Depends on your priorities. Also, it is usually cheaper to buy a race car than to build one... Also the sound of your exhaust is more a factor of the cat back than the headers.

 

Uh, what? Since when do LT's not make 20-30 HP??? I think it's about time you quit picking out my posts. I have seen people make 28 horspower with a full new exhaust system.

I don't even know what they list as the manufacterer, sorry. Notice how I never said 20-30 RWHP, 20-30 HP at the fly=BHP.

 

Well i dont have a dyno # but when i did long tubes off road y and a ctback (along with upgraded wires and plugs, old ones were fine but i went with something nicer while i was there) and it made the car feel like a whole new animal. Before it struggled to spin the tires a couple feet out of the hole even with a lil brake torqueing. Now i can roll into the throttle and lay 2 stripes for 60-80 feet easy. Made a WORLD of difference. Now thats a full exaust, but im sure people arent adding long tibes to stock pipes and catbacks. Id say a COMPLETE exaust is worth 20-30HP easily.

Car is stock other then a K&N cold air induction. 3.27 factory gears.

 

Actually quantifying the true value of any exhaust on any specific combination can only be done on an individual basis. Both flow and velocity are important for performance and efficiency. Intake, exhaust, and eveything in between including the gearing and torque converter will have a bearing on the "perfect system".