LS3 intake options

[Dbunch9]

So I’ve done a ton of reading around this forum and corvette forum the last few years about a lot of LS3 and camaro topics and it seems there really isn’t a lot of options that make sense when it comes to the intake manifold. I see atleast 80% of people on here say port/rod mod the stock intake which seems like a good bang for buck option, but from my understanding it doesn’t change the RPM range at all. So I’m wondering, if my gpi ss3 cam peaks at 6600ish on the stock intake, maybe it would peak higher with a different intake and net more hp up top? I see lazerlemonta doing crazy things with the LOD intake but I don’t want build a valvetrain to support over 7500rpm but I’m looking for something in between the stock intake and a short runner intake... is there an intake that could extend my rpm range to peak around 7k that makes all around better power as well? I see fast has the mid runners you can swap into there intake and the long runners with a 102mm throttle body made more power than the ported rod mod with a 92mm throttle body according to The GPI intake test.

[Black_SS10]

In short, as you increase runner length you push the powerband to the right. Thus increasing where peak power is made. Many times the downfall is lost low end, or torque. That is why the stock or ported rod modded manifold is the best of both. It increases power across the entire poweband without sacrificing anything. It doesn't make high numbers. It is great for a daily street car. If your cam peaks at 6600 then 7000 is pretty useless. 6600 rpm is where the factory and the ported manifold start to fall off, since they have the same runner length. If you were to swap manifolds, sure you may pick up more on the high end, but at what cost to your low end?

[Dbunch9]

I always understood that side of the argument but I also, whether stock or head cam, have lost almost every race starting with the rpms in between 3-4K which it seems like is where the shorter runner intakes lose tq. Seems to me it’d be worth it if I had a better flowing, medium runner intake that kept carrying up top making more power no? Even if it meant losing torque where I don’t need it when trying to go fast. Seems both ported rod mod or fast will gain 10hp/10tq, but what if the fast mid length peaked at 7k and peaked higher hp than the stock because the cam isn’t being choked past 6500rpm. My facts may not be 100% straight but I believe lazermontas ss4 cam supposedly peaks at 7200 according to gpi but with his lod intake doesn’t it peak higher than 7200?

[Greenhornet2]

I think you're over thinking the intake. Are you auto or stick? If auto and you like to race I'd do 2 things if you want to race, 3.91 gears, higher stall converter best bang for your buck for ETs. M6, just the gears. If you've already done those then I'd start worrying about small power increases.

[Dbunch9]

Well that’s the thing, I’m an m6 with headers, cold air, cam, heads and 3.91 gear. After I beef up the axles and put in an Eaton, only performance mods I wanna do are a lightweight clutch and intake. I don’t personally have enough interest in this car to start fly cutting pistons or boosting at the moment cause down the road I wanna step into a vette. Just wanna see what I can squeeze out of my current head cam setup and have fun with it for the time being. I wanna change the intake eventually so if there’s a better option then just porting the stock one is be interested in going that route. What I see is my cam peaks where the stock intake falls off so I feel like it’d still keep pulling If it had an intake with shorter runners, the catch is I just don’t wanna put the effort into a 7500-8000rpm too end so I’m curious if there’s a nice median. I’m pretty interested in the mid runner fast but I don’t see much about it, I’m just curious if anyone has input or can suggest a different intake. I appreciate any input tho, I enjoy the discussion!

[Black_SS10]

What is the powerband of your cam? That will help you decide what manifold is best for you. For some it is all about peak numbers, while for others it is the area under the curve and how it performs.

[Dbunch9]

I don’t have a dyno graph to post but the car feels stock till 4000-4500, from 5000-6500 it pulls hard and seems to stop pulling hard after that (7000rpm limiter). Everything I read about the stock intake is, it either table tops or falls off around 6500. I could be wrong but in my mind that doesn’t mean the cam won’t keep making power, and if a ported rod mod or ported long runner fast will add 10hp/10tq to my current powerband, what if I find and equally as good flowing intake that pushes the powerband to 7000-7200? Maybe it’ll gain 20hp/10tq?

[Black_SS10]

I don't mean a dynograph, I mean the operating powerband of yout cam. For example, 1500 to 6500 rpm powerband. That is where the cam makes power. Can it can some past the 6500? Sure, but most times it just falls off. It is just like an intake manifold, they have an powerband. If it was as easy as slapping any cam and manifold on then everyone would be doing it. The manifold can flow for 7200 rpm, but that doesn't mean the cam makes power up to 7200rpm. Many times there are trade offs. Want peak power? Lose torque and maybe midrange. Just because a car makes peak power at 7200 rpm doesnt mean it is a fast car.

[Dbunch9]

Just checked again, website says very strong to 6900, but I remember my dyno graph falling off at 65-6600, see what I’m saying? Seems like the intake is restricting possible power from 6500-7000. Maybe it’s not worth the money or worth the hassle of finding 5hp at 7000 but I’m trying to squeeze what I can out of this cam without spending thousands on a valvetrain setup for high rpm.

[Bo White]

https://youtu.be/u1MhOREyL3g

[Greenhornet2]

I'd be contacting JRE with these questions personally. Maybe your tuner started pulling timing. A lot of tuners will do that to keep the rpms from going above what they feel comfortable with.

[Dbunch9]

Wow I think the video Bo posted is all I need to see... guess it just really doesn’t get better than the stock intake lol it’s crazy cause I even thought the Holley hi ram wasn’t gonna lose down low and would only gain up top, I just wasn’t willing to hack up the car but damn it lost a good amount down low as well.

[Juiced1]

A ported LS3 is hard to beat. Some of the stuff they are selling out there is hot garbage, especially when you consider the price. Your SS3 cam will operate excellent with a ported manifold.

[Bo White]

I love my Edelbrock Pro Flo XT manifold granted I spin mine to 7500 and have a 6000 stall so I don't care much for what the manifold lost below that as long as my stall flashes as speced