Vdop

iTrader: (2)

The one that hangs on better after peak and is shifted higher will win.

HioSSilver

iTrader: (8)

As i have already said if you're camming it and not extending your rpm range then you're doin it wrong.

Some of them have pretty substantial gains at 7k......and I'm not talking about stopping there. They shoulda ran that test to 7500 and used a cam that would run to that with shift point at 7800ish. That would've been a good intake test. You would've likely seen 100hp difference in the ls3 intake vs the others then.....maybe more.

big hammer

Yeah I don’t get it either. Anything over 6500 is some kinda taboo around here

stevieturbo

But only if you're revving high enough to drop where it is making more power....and lets face it, on most of them none of them were excelling in that respect.

The only one you might want to rev harder on that combo is the HiRam.

The stroker engine is harder to tell, as both the ProFlo and Carbon intake seemed to work well up top.

But with torque taking a huge dive....is there really any point taking it to 8k to shift ?

stevieturbo

I'm sure they could do hundreds of variations too....if someone is prepared to pay for the test and supply engines etc.

It's certainly a better test than any intake manufacturers have ever offered !!

spanks13

iTrader: (5)

I would argue that people with built motors are the primary customers of aftermarket intakes and this article missed the boat by a good margin. As seen, the stock ls3 intake is a bad **** up to 6000 rpm with a stock stroke. I'm just tired of reading LS3 articles since 2007 that say "this component isn't really suited for our mild cammed ls3, but here are the results"

The article did say they reved the thing out once and tagged some intake valves...so they were wise to keep the revs where they were at for most of the test.

I wish they had at least told us the cam specs for the stroker. Ideally the camshaft would have been the same between the stroker and the crate motor. Hard to compare anything when the cams are different. I suspect the stroker cam is quite a bit larger, even when accounting for displacement.

Runner length on the FAST 102 is 8", 6.25" and 3.5". I don't know factory runner length. Volume is 680cc, 460cc, and 300cc. What's interesting there is that the "cc per inch" is 85, 76, and 85. A victor Jr. has an average runner length of about 6.25" as well.

It is definitely interesting to think about. The 4" stroke will put more demand on the intake with ~10% higher piston speed, but the runner tuning is dependent only on RPM and the timing of the pressure wave in the intake tract. If the short runner intakes are designed around a 6000+ rpm harmonic, that tuning point won't change with stroke.

I think the main contributing factor when thinking about long vs short stroke is that a longer stroke engine will more quickly reach the point where outright maximum flow is the most important factor in cylinder fill. The shorter and straighter intake runners will be better for performance as they're less restrictive and the air column has less intertia. At lower engine speeds the short runners will not offer any harmonic tuning, risk pushing the intake charge back out the intake valve after BDC, and won't have the velocity needed for good cylinder fill. All this is seen as a loss of torque in the midrange.

spanks13

iTrader: (5)

Most seem to want to know if the stage 4 cam will still be driveable in a parking lot because it sounds so much cooler than the stage 2...

HioSSilver

iTrader: (8)

Good post spank. Intake harmonics are intriguing. I'm very surprised there are no variable length runners out there.


Yea most of those stage blah cams are poop and only good for sound. When your cammed ls3 only makes 460whp and 430wtq you did it wrong.....because a ls3 is capable of 470whp/470wtq. I see way to many stage blah cam swaps with **** results.

G Atsma

True, but the article was ALSO about proving how good the OEM LS3 manifold is. There are MANY who run mildly cammed LS3's, who might be wondering if it's worth upgrading the intake manifold alone. This article proved it is not necessary, though no harm would be done if one chooses to do so.

big hammer

The stock manifold is very well matched to the Stock heads. It does restrict ported or aftermarket heads. However most people don’t even utilize what they have because they don’t rev over 6500

big hammer

If you’re just running the hip new shelf Cam, a BobbyDean stage 4 CAI, 22” torque thrust 2’s and a hypertech I doubt a manifold upgrade is going to help you

G Atsma

LOL Right!

stevieturbo

Although it basically shows the same thing as the cathedral test.....

below 6k, there's little out there to outperform a stock intake, value for money. The aftermarkets are a little better than LS6 etc, but still not huge.

With the LS3 it's even less pronounced

stevieturbo

And again, that's because most dyno graphs have already peaked before 6500rpm anyway

Have you graphs to show where the LS3 intake is restricting an engine vs other intakes on the engines you describe ?

Does the crossover point differ ?

big hammer

If you’re peaking before 6500 your engine is built bad and you should feel bad. Stock ls3 intake flows the same as Stock ls3 heads. So if you put that intake on better flowing heads then guess what it’s a restriction. Also the runners are tuned for 6000-6500 so once you start revving to 7000-7500 like you should be then it’s even more of a restriction again. A Stock ls3 intake on my ls3 would probably drop me 50-60 hp

HioSSilver

iTrader: (8)

I bet it would drop you more.

A ls3 intake is good for a ls3 cam run in the oe operating range. That's about it. Once you start camming it and dealing with reversion it's tq production goes to **** pretty fast.

Darth_V8r

iTrader: (4)

Imo it has to do with power past peak. You can gear reduce to gain torque but if you can carry it longer in the lower gear before uoshifting, you lose way less tq on the upshift. Shifting at 6500 you lose a ton. Autos may be different because the stall can smear the gears a bit but manual needs that past peak power

stevieturbo

Yet almost every graph there aside from those "bigger" intakes they're peaking a little before 6500 in that test.

And torque has already nose dived long before.

So lets see these graphs of yours and your intake excelling all the way to 7500 ? Maybe if you could prove it to people more would try ?
What cam etc ?

Vdop

iTrader: (2)

Torque always noses over before hp peak, that's how it works. Torque will be falling but if rpm is climbing and horsepower doesn't take a drastic dive it'll still be faster shifting higher. Only the tow truck intakes give up hard after 6600. Several of the intakes in this test appear like they would excel with a 7500+ shift point even with the baby cam and stock heads, but we can't tell how far because the test was ended early, that's the point people are trying to make. A set of valvesprings and another 500+ rpm would have offered much more valuable data.

HioSSilver

iTrader: (8)

Then that should tell you that almost erryone of those intakes are a restriction of some sort after 6500.

This goes on to what i said before. The ls3 intake is a great match to the ls3 cam. It seems to fight larger cams and is not efficient with them.