c5blkvette

http://www.hotrod.com/articles/giant...dyno-shootout/

Surprisingly, I think the clear winner was the Edelbrock Pro-Flo XT LS3. This manifold even beat out the Performance Design (carbon fiber) manifold that had a 102mm TB. And the Edelbrock did it on a 92mm TB and 1/2 the price... just WOW!

The other notable takeaways:
- The stock LS3 intake handily spanks everything up to about 6000rpm
- The Holley Crossram didn't have as much top-end as I would have thought (but was the only intake that outperformed the LS3 across nearly the full RPM range)
- The lone ITB system performed pretty poorly

Summary:
If you want max HP and willing to sacrifice bottom end, buy the Holley Hi-Ram or Edelbrock XT LS3
If you want best performance for street and under 6000rpm. Give some respect to GM and their stock LS3 intake

big hammer

Mid runner fast ftw for us ckearence challenged folk

KW Baraka

iTrader: (7)

Or Gwatney.

KW

NHRATA01

iTrader: (10)

It was a pretty comprehensive test but yeah that would've been one great add, a radius bar'd stock LS3.

blackbyrd

iTrader: (14)

I was hoping I would find something that would sway me, but seing how the stock ls3 did on that big cube setup makes it hard for me to want to swap.

Gasoholic

iTrader: (1)

If Edelbrock told me they were giving me one for free I'd still tell them to keep it.
Used to be a reputable company but times have changed.
Screw me once and that's all it takes. Have better places to spend my money.

Darth_V8r

iTrader: (4)

The LS3 did great, and really is a phenomenal stock intake. I personally thought when you started looking at the aftermarket stuff the midlength fast gained the most while giving up the least. I also thought that some of those intakes are designed for 7K-8K RPM, and not revving them past 7K was a disservice. Many of them had not even hit peak power yet at 7K, but the pull was ended, so that's that. When you start looking at power past peak, lots of those intakes were just hitting their stride. On a street motor, though, I don't think you can really argue against a LS3 intake.

The ITB result surprised me. I'm thinking the 50mm throttles are too small or else the runner length was too short. Something was amiss. Most often I see ITB making great torque vs plenum-style. Wish they would have tried a Jenvey or Harrop. Oh well.

stevieturbo

Link in first post didnt work for me ?

This does

http://www.hotrod.com/articles/giant...dyno-shootout/

Yet again it highlights how good the factory intake designs are though ! Especially in the rpm's 95% of users here actually spend most of the time

stevieturbo

While some may be designed for 7k+....was the engine they were testing them on ?

You can see the graphs and where they peak/fall for bother power and torque, most were already falling off anyway at 7k, so was there any point pushing further ?
The engine may need cam/valvetrain/head/other mods to head beyond 7k safely.

One thing for sure though...short runners suck. There's probably a good balance if you can get 8-9" and decent size to maintain torque and also allow it to go high.

big hammer

A Stock ls3 intake is perfectly fine for cookie cutter builds

383z

iTrader: (2)

Im with you.
I want to be convinced to buy the FAST intake for my build, but I will only have a stock inch LS3 with GMPP heads, TSP F35 or simiar custom cam from Pat G, and all the supporting mods (U/D pulley & electic water pump and all) to try to get to 500rwhp through a 4L60-E.
I dont know if Ill hit it, but every 10rwhp part adds up.

Plus, I dont even have a stock LS3 intake to start off with, so the difference is about $600 to get one or not.

blackbyrd

iTrader: (14)

When I did my build it was either a.custom sheet metal or the ls3. There wasn't a fast option when I did it, actually there wasn't "ls3" heads just the l92's. Paid 150 for my intake and went on. Thought I might change later on, but I really don't want to loose my low end torque for a little gain in the high end. I make 400 ftlbs at 3000rpm, and I'm still need to finish up my tune. All on what I call a pretty concervative budget build

JoeNova

Sad just how bad the Holley Mid Rise performs in both cathedral and ls3 port.

spanks13

iTrader: (5)

The whole test needed to either be run to 8000, or run everything on the stroker. They always seem to get 90% of the way there and then blue ball you with these tests lol..

The crossover point for the short runner intakes with a stock stroke was around 5900-6200 rpm. With a 4" arm that would bring it down some, maybe 200-300 rpm lower? The longer stroke puts more demand on the intake, but the tuned length of the runner is a fixed relationship to RPM not piston speed, correct?

If these intakes made more power than the ls3 from 5500 rpm up, anyone who could drive a 6 speed would be significantly faster in the quarter mile. On a road course or autox you better like to shift. Could potentially be beneficial to give up some torque at 4500 to get out of corners, but it would be difficult to give up 50 ft lb coming out of a corner and still be faster.

I'm surprised at how well the low profile sniper ran, although it gave up more torque than the fast 102 w/ med runners, and didn't make more power until 6200 vs the FAST matching the ls3 at 5900. The curve was really taking off above 6000 and did make 15hp more at peak than the FAST..

G Atsma

What percentage of LS operators have strokers? NOT many. So running the tests on stock displacement was far more applicable to the majority of users. What it told me was, as said above, the LS3 manifold would serve well for a majority of users.

Vdop

iTrader: (2)

Well, at least the tow truck drivers know which long runner to choose. This test would have been wayyyyy more worthwhile with a grown up cam and some rpm. What a waste of time.

Darth_V8r

iTrader: (4)

I keep going back to on older test Tony did on the LS7 MSD vs the stock LS7 intake, and it made more torque all RPM's. the entire curve was higher. So, I tend to think longer strokes can use the shorter runners better vs shorter strokes. And since the LS7 is a 4" factory stroke, that data has relevance to a decent sized group. ANyone know the stock LS3 runner length? Stock LS7 intake runner length is only 6.875" long on the short side radius.

This test in a way shows that. When you look at the 415CI test results, the torque curves match up better shorter runner vs stock. That could be a function of the intake OR it could be a function of the longer stroke, OR it could be the combination. Problem with confounding data is it's harder to draw conclusions. ****, overlay the 425 and LS3 results on the LS3 intake, and the HP peal is lower by 200-300 RPM.

100% agree here. Those gear splits on the manual make it so that 7500RPM shift points make a huge difference in 1/4 mile trap speeds vs 6800 RPM, because of where you land on the torque curve and how much RWTQ you lose on the upshift after gear multiplication. But, on a road course, and I admit, I'm no road course driver, I'd guess midrange would be more valuable vs top end.

stevieturbo

I'd say the opposite....given how terrible they look, I'm amazed it performs so well ! I'd expect much worse.

HioSSilver

iTrader: (8)

Why the hell is erryone so scared to spin past 7k with these engines? That test included. To me they dropped the ball bigtime on that test.

Typically when you go to the effort to change a cam you're also looking to extend the rpm range.....if you're not then you're doin it wrong. That allows you to take advantage of making torque through gear multiplication. Example

3.73gear x 400tq = 1492

4.10gear x 400tq = 1640

Now taking that into consideration you can lose about 35tq in that scenario and still have 1492tq with 4.10. So typically you're not losing any tq that accelerates you with 4.10 and 365tq. So if you utilize being able to rev to 7500-7800 with these intakes that run to higher rpm your over all gain will be there. .....even at low rpms like some is concerned about.

stevieturbo

When power is falling off, torque already falling off, often considerably.....what exactly would be the point in revving it far higher ?

There's only a couple that are still hanging on at 7k so even then still not much point in taking them higher as they've already peaked.