knowing lt's are not smog legal im telling my dad 2 go with them and some cats becasue shortys are waste of money (from what i heard) and some guys over look lt's with cats. Or we can just go with switchin back 2 stock manifolds . so main question what do you think about performance wise lt's vs. shortys

 

Shorties are a waste of money in my opinion, that is why I went with the LT's. What I am doing when I get tested is most likley swap the stock stuff back on. Mostly cause I have an ory. If you can find someone who will over look the LT's go for it, otherwise swap it all back on. If you do choose shorties dont excpect that much of a gain if at all. LT's all the way!

 

I respectfully disagree. And I'll tell you why. There is little evidence in the direction of this claim. I suspect the shory hatred has spewed from the **** tossed around by folks who are CHEAP and simply install shorties with no vision about the final setup. There is plenty of valid information on long tubes so if pure performance is what you're after then by all means try a seach and you'll be busy for days.

Let me elaborate, ok. If you are strapped for cash, then yes, shorties are a waste, because by themselves, they do diddly squat. Or do they? I have a moderate shorty setup and put down 344 rwhp and 343 rwtq and I am WITH cats. And only small 2.5" carsound cats. I suspect if I install 3" cats with reducers on both sides the number would go up considerably. I am smog legal. I know if I remove the cats, then the numbers would shoot up even more, but I'd have to smell fuel, listen to an assinine sound, and be loud as hell. Basically a street magnet for cops and wantabes alike. I don't drag race, although for that it's a different story.

I have a tuned setup and did not skimp on any supporting components. It's a catch 22 though, since if you design the car right and do the same with mids or long tubes, once again we're playing leap frog with horsepower. How fast do you want to go? How much do you want to spend? How *legal* do you wish to be?

In the long run, it is IMPOSSIBLE for shorties to make the *TQ* of long tubes...they just don't have the same amount of scavenging, and factories haven't invested the time to waste on a small market. However, top end for *tuned* shorties should be close if not identical to long tubes, because of the way pulses work at high rpm. It's simple physics there really, there is nothing special about ls1 engines that make them unique. Of course 'master' technitions at the GM dealerships would lead you to think differently, as would I if I had nothing to sell.

Now, if you were to ask the same question, the only way to *properly* respond would be to match the setup with your goals, future modifications, and how you will run the car. Can you do that? Considering the fact that shorties by themselves are difficult to match with a proper setup, usually it's a no brainer. Especially for 2000 on up because they're cast iron exhaust manufolds flow fairly well so I've heard and there is little evidence to the contrary.

:popcorn:

 

Like I pointed out in your other post..

I have shorties and only got 356whp with a TR224

I know it's not my car cause there's another guy in this area with nearly identical mods and is getting nearly identical HP.. both of our cars were professionally tuned.

Aftering seeing other people's dynos with this cam, It looks like Im down like 20+whp and the shorties/stock y/cats have to be the bottleneck.

Im gonna get LT's w/ cats after I smog in July. If I cant find a shop to pass me, Ill just have to swap everything..

 

Ther e are other reasons for running shorties besides legality, installation, and peace of mind, like decibal level, ground clearance, and cost (I picked up mine from another member for a reasonable $150).

I'm glad you mentioned your setup, because you are missing a few pieces of information...what cats and y pipe are you running, and do you have plans for a modified throttle body. I know they might sound like quibbles, but the TB will add around 10 hp and if you happen to have cats that were installed at an angle or a collector that doesn't transition well, then, there's another 10 hp.

I don't mean to over analyze setups, however with shorty headers it's more crutial for you to get components designed for the application and as you know each car is different. For example, the TR series has also been known to dyno right around 340 on a *stock* exhaust. Your exhaust is far from stock, but it goes to show how much a of a variance a single pattern cam has on various builds of cars from various years and spans. A 224 cam will generally reach peak hp somewhat past 6200 rpm so that may factor in also.

If you could provide some more information I believe it would be helpful for sake of analysis. There are no right cam combos and it's possible the same setup would produce drastically different numbers with just a tweak or two.

 

Im running the stock TB, Y-Pipe, and cats..
The other guy has the same setup, but he has a SLP Y-Pipe.
I plan on a TB which should hopefully give me a few more hp.

The plus to my current setup is it passes smog with flying colors..

 

Stock y pipe and cats aren't as poor as you might imagine. With that on there instead of duals and carsound cats on my current setup it still made 345 rwhp but a bushel load of less tq (like ~20 lb ft). The cats were 80k miles old but didn't look it, and my tuner said they probably wouldn't pass smog with that setup.

However, you have a good point obviously there is a constriction in the system that you identified. Now simply switching from stock y pipe to high flow might not net you 20 hp. If you were to add true duals at the same time now you've got something. You might be able to comme close to 380 hp with those mods, which is right around what long tubes and less of a compete setup might net.

I estimate once you swap out the y and cats, and if you can swing duals and another tune, you would see north of 370 rwhp and more tq. That's something you just don't see if shorties these days. If you were to add a tb to that then of course it would not be *another* 10 hp, in essence just a placeholder mod for heads down the road.

 

I totally agree with what you are saying. However, his dad's car is a 2000 and like you said the stock manifolds do flow really well. Thus, if he does decide to go with shorties the gains will be there, but not as much as if he goes with LT's. LT's do come at a risk, you got to by emissions, if thats something that he doesnt want to hassle with then by all means go with shorties. Your car is proof that shorties can put numbers down, but every car is different and responds differently to mods. Your car is strong for what you have done. As from what I read his post, he is willing to deal with swapping the stock stuff back on for emissions if needed. Shorties are not that cheap either, for the price of them you could of gone with LT's. From what I gathered in his post he is after performance and wants to go with the LT's. If I'am missing something please correct me .

 

I like Mac mid lengths....From headers to tailpipe,under $900 for the complete set up.Offroad y is o.k....just get the 02 sims out of summitracing for $100.I am completely satisfied with mine.But with making just that little bit of extra horse,I'm getting a wicked y pipe baning sound on the floorboard.Watch out for that.Some people dont get it....others do.(Ypipe bump stops)there on back order....figure that one...............just a heads up...see ya

 

I'm with 98t56TA - shorties as an only mod dont do too much because the gains are hurt by the other restrictions in the system. The stock y-pipe and cats have been shown to rob around 10-12 rwhp on the dyno. Most shorties with stock cats have an increase of 8-10 rwhp. Therefore, add shorties and no cats and gain ~20rwhp; within 5-10 of long tubes. My car is making 320rwhp using shorties with stock TB, and LS1 intake, and cats in a automatic. With a new intake, ported tb, and no cats, I'd be around 340-345 in an automatic car. Add a pulley and tuning and I should be at 350+.

 

I am making good power through shorties. they are not robbing me that much you just need to remove the factory cats and install the mufflex test pipes and then get a better y pipe than the flatened factory one such as lg's y pipe or the slp y pipe then the exhaust is much more opened up.