i dont want this to turn into a ground clearence or true dual vs single exhaust debate. im just wondering when its nessisary to run long tubes or if they are better then shortys even on a stock thirdgen. im debating wether or not to order the 2055s or just go for the 2210s. my car should put down around 300rwhp approx 350 crank when its together. im just not sure if its beneficial to run long tubes for an engine producing that kind of power.

 

at the power level you are at i would stay with the shorties,when you hit the 400+level is when you will need lts,another factor to look at is your gear ratio,stall conv.,camshaft.....if you have a steep geat like 4.56 and a cam of say 245 or more @.050 and a stall of say 3500+ you want lts for sure,i have run in the 11's with hooker shorties w/355 cc306 and tfs heads,3500,4.10s,26X10 ET STREETS...

 

alright. the engine wont see over 6,000rpms, peak power should be around 5500. 3.45 gearing. pretty mild. lets get some more replys!

 

You will always make more power with longtubes but for your application shorties will suffice. I will always sacrifice a bit of power for the sake of fitment and ground clearance.

 

Car Craft did a huge header test and the shorties always made more horsepower. If you look at most race headers, they arent a true long tube header. Most (like hedman huslers for example) merge like a mid length or shorty would.

The benefit of LT's is more low end torque in every test I have seen.

 

Hi! Can you state the car craft issue????????

 

I don't remember, it was within the last year I would say. It was either Car Craft or CHP but I am pretty sure it was Car Craft. They also compared 1 5/8 to 1 3/4 to 1 7/8 if I remember correctly.

 

If a shortie makes more power than a long tube, there is something very much awry. But the majority of headers of either variety are designed more for ease of fitment and production than for maximum useable power. Under ideal conditions, a properly designed and fabricated long tube will always out-perform well designed shorties by about 15-20 HP. Unfortunately, we do not live in an ideal world...

Also, there is no way a car making 350 HP at the crank is gonna get 300 HP to the wheels. More like 200-220 at the wheels. Crankshaft horsepower is higher than Flywheel Gross, which is higher than Flywheel Net (with accessories) which is higher than Rear Wheel (Net). I know you are guesstimating, but you need to be realistic with your estimations, or you are gonna be really bummed when you get it running.

 

thanks for the input.
when i can get the car to a dyno id be more then happy to share my numbers with everyone, as u can see by the pic in my sig that wont be any time soon. haha, but even if my assumptions are incorrect 15% of 350 is 52.5 which would give u 297.5rwhp

 

https://www.thirdgen.org/techbb2/new...postid=2099208

 

This was in no way a thorough test, they just slapped the headers on and ran them, and cannot explain their results. If you read the story, their results totally disagree with what the writer of the story tells you about header design parameters. That should have sent up a red flag right away.

Every engine package will reach a harmonic (it's called tuning) in a certain RPM range. Tune everything to a certain RPM range for max power, tune everything to a strategic mismatch for a better power spread. Just throw parts at it and learn only what that particular setup responds to. By giving no detailed info on exactly what the engine combo is or what it is tuned for, this article is worthless for anything but THAT PARTICULAR COMBO. Even worse than that, now we have newbies running around telling more newbies that shorties make more power than long tubes. But they got the important info right, they do tell you how much power the engine makes, how much it is and where to BUY it. (go boy, go fetch!!)

This engine system has some odd tuning to it, but we don't know what or why, and they provide NO INFORMATION nor did they TRY ANY ADJUSTMENTS to the standard variables, such as fuel curve, carb size, manifold type, ignition timing, cam size, cam timing, or anything of any relevance for that matter. Even the most experienced engine builder needs to test different combinations to find packages that work best together, if everything on an engine was simple and easy to predict, we would not need dynos. Since we know nothing about the package, and did zero experimentation to figure out what was causing the strange results, the results are not valid for anything but that particular package, which we know nothing about.

 

The most important things are primary tube diameter, primary tube lengths, and port entry match.

Theres a really good book entitled "building and modifying intake and exhaust systems".

Also, I know you said you didnt want to get into a ground clearance debate, but keep in mind the long tube needs to run by your hydraulic clutch components.

-- Joe

 

No way a 350hp car will make 300 to the wheels? Well LS1 punks must be very lucky since they make "310hp" fly and get almost 295 to the wheels in test I have seen. Dumb world we live in.
LT's are great for low end, like everyone says, but I rather have some decent midrange as well. I say go for the shorties.
Good luck on the engine SLP let us know how it turns out.

 

So you have engine dyno'd a ls1, then immediately stuck it in a 4th gen and chassis dyno'd it eh?

-- Joe

 

Nope, just going by what I have read thats all. Check Chevy High for Feb 05, a LS1 is in there in the STS turbo mod. Very cool!!!

 

An LS1 will make 410hp on an engine dyno. That is why you see 300+ at the wheels stock. It is no secret that GM fudges its HP ratings. They have been doing it since the early 60's.

 

Exactly what I was getting at.
Its all over the place about LS1's making horse like that. Thats why its so hard to play catch up.

 

And why people are unrealistic. They say "man that cars 350hp and it goes high 12s" its like. uhm. right dude.

-- Joe

 

LoL, dude not trying to fight with you. I pretty much agree with you. I got a buddy in the club with a 02 WS6 with the T-56 and has a cutout and a tornado fan(just found that it had one he bought it used last month), he went 13.0 here. In my head there is no way a "stock" WS6 can do that(a 13.0 here is a 12.0 more or less at sea) but it did. Underratted I know, realistic, I am. Look at what I am driving, do I lie and say it runs 13's....nope. I wish so I am pretty realistic. Again not trying to fight with you. Opps off topic.

 

I was agreeing with you.

-- Joe

 

For future people that come in here. Sorry I am dead on my butt, be working for 15 hours and hating life. I am all mixed up. Someone stick a fork in me I am done.