GrEeNdAyZ

Whats the real deal here....is one better than the other?....if so why?.

If I ask this question enough I always get a different answer/opinion.

It seams most people are using Hooker LT's...but there are certenly cheeper solutions, especialy in a shortie.

thanks

Dave

Achilleus07

Long tubes= Better airflow = More power (and in my opinion better sound)

GrEeNdAyZ

Granted, but is it the number of bends that make the big difference.

A shortie with 1 5/8 primary and 3" collector Vs a LT of the same dimentions....how much of a difference are we talking about 1cfm 100cfm?

Slalom4me

Guys, there's a bit more involved.

Here is a quick primer that you might find helpful.

Don't get too wrapped up in some of the voodoo
names and products.

If you want to dive into the deep end, I agree the
book they mention is a good source of information
- ‘The Scientific Design of Exhaust and Intake
Systems' by Phillip H. Smith’.

.

Strick

In very simple terms, long tubes help scavenge better than short tubes. It's in the design. Better scavenging increases your horsepower potential. BUT this is only in the higher RPM ranges. That's about as simple as I can put it.

There are reasons for shorties as well as long tubes.

Shorties: easier to install, replaces the iron rusty looking manifolds, provides a small increase in flow potential, meets EPA emmissions, and they sound better than the manifolds.

Long tubes: You have to go with new cats (if you need them), provides better flow, sound is better than shorties and most states that are stinkers on emissions don't allow them.

CFI-EFI

It IS all about scavenging. The problem with shorties, is that because of their length, that are "tuned" for an rpm range you can't or won't often use. Therefore, they are of extremely limited value on 90+% of our cars.

RACE ON!!!

VenkmanP

http://www.sporttruck.com/howto/1482/index3.html

http://www.grandsportregistry.com/dyno.htm

vader86

Shortys=5-7
LTs=15 or so on an L98.

Slalom4me

Wow !

On top of 'small ID vs large ID' and 'cats vs no cats',
now we have shorties vs LTs.

I'm going to make myself comfy and jes' set back
a spell ...

.

GrEeNdAyZ

Hey thanks to you all....

I understood that the different lenghts would move the peeks up and down the rpm range.

thanks steve for the dyno comparison, from the strong opinions that i have heard from LT users i had expected a greater difference. Very surprised that there was only a couple of HP and a couple of foot pounds difference in the 1 5/8 pulls you have there.


thanks again guys.

Dave

GrEeNdAyZ

thanks there was some good info there!!

Slalom4me

You don't indicate which engine you have.

Just keep in mind that L98 shorties are built
a bit differently than those ones in the test.
The ones I've seen look like block huggers
and resemble the OEM manifolds.

.

Corvette Kid

This doesn't indicate the benefits of long tubes in the lower and mid-range of the torque band either, which is where our engines will live most of the time. Also notice the lower peak torque for the big headers.

CFI-EFI

The numbers quoted in the chart are interesting, and may help someone win a bar, or a bench racing bet. They are great if you are driving a dyno or never let your rpms wander out of the 4500 to 6500 range. Remember, there is a lot more to a power or torque curve than just the peaks.

RACE ON!!!

VenkmanP

Pretty much everything I've read says shorties give more low-end torque, which is what most of us want.

If you have dyno results to the contrary, let's see them.

88BlackZ-51

My point of view is why do things twice. Dave is thinking of doing a 383 in the future, or a motor build up. That is why I went with 1 3/4 Hookers. Didnt want to spend money twice. Plus, My L-98 has enough torque allready, Its the higher RPM's that I want to increase.

CFI-EFI

Pretty much everything *I* have read makes the point of longer tubes promoting stronger torque and at lower rpms. I haven't archived the dyno evidence, but your first post bears out my point. Shorties = 396.1 lb-ft at 4,700 rpm. Long tubes = 397.8 lb-ft of torque at 4,400 rpm. The amount of torque at their peaks is negligible, but the point at which the peaks occur makes MY point. I think seeing the whole curve, as I mentioned in my previous post, would be rather enlightening.

RACE ON!!!

vader86

Pay very close attention to what is compared, and how it relates to the L98.

Corvette Kid

And everything I've read on it, which spans decades, would lead me to the contrary conclusion. If you read the whole article from Sport Truck that you posted, it is so incomplete and there are so many variables as to factors re/ performance differences in the the two headers, I fail to see how they were able to draw any conclusion in that respect. Switching back and forth between 1 5/8" longtubes and 1 7/8" long tubes would be one glaring example. The point is, in short, there is nothing in these dyno results that proves anything.

VenkmanP

So post some dyno results that prove something. In three years of reading "shorties are worthless" all over the place on this forum, I've never seen one shred of evidence posted to support the claim.

The comments about wanting to see the whole dyno sheet are quite valid. I want to see them too. Post some.

Until then, we have some evidence that says the claim is false. It may not be the best evidence, but it's all anybody has offered.