I am considering a cai system for my 2013. What recommendations would you have. Do you really feel any performance addition and will this affect my factory warranty?

 

The filter is excellent on the later C6s. I just pushed the shroud back so only outside air through the grill gets to the filter/intake. Every degree cooler the air is adds hp--obviously, at highway speeds. You can pick up an easy 10-15hp with this mod and it is easy to return to factory. There is no "ram air" unless you go to a blower/turbo. The engine sucks in what it needs, so lowering the temp of that sucked in air is a free boost. Some swear by Vararam, etc., but I don't see the gain for the $400 cost. The engine will still only take the air it needs, and with the shroud open, more cool air is available than any CAI gives. The whole bay is essentially outside temp air and the shroud still keeps the condenser heat away. Still plenty of flow to the condenser/radiator, so that isn't an issue.

 

Yes, the engine takes what it needs. But if you take air that is of higher density when you have ram air, then the engine makes more power. Even though I do not have a vararam on my car, I do believe that they work at higher speeds. The ram air affect at 100 mph would give you another .17 psi (stagnation pressure at 100 mph). That is another 1.1% in air density which will give you around .75% more power (another 3 hp). Mind you it's not a lot, but it's also not nothing.

Look at it this way. Your stock intake sucks atmospheric air and takes what it needs, but it's 14.7 psi air (sea level). With Ram Air, the engine sucks what it needs but the air is at a higher pressure at 14.87 psi which is denser air and therefore the engine makes more power.

Now with all that, what is really important is sucking in air that has not been heated up by the engine compartment. If the air you suck in is at ambient, say 70 degrees, that's a lot better than air that has been heated up by 20 degrees. Air density goes up by proportion of the absolute temps. So sucking 530 (460 + 70) versus 550 degree air makes a large difference. The hotter air is 3.8% less dense.

So after all that, I'm agreeing with Corvetteflier, it's just not worth the extra $400 to get another 3 hp when you can get a bigger gain with just getting cold air with the free shroud mod.

 

The actual gain from Ram effect is much higher than what is listed. Even if there was ZERO pressure rise. The intercooling of the entire induction system is what you are after.

If you start a car on planet earth and bring it to operating temp, the air temp INSIDE the intake manifold plenum will rise. On an LS-3, we see about 20-60 deg above ambient temp. If the MAF is reading ambient, you will still see 20-40 deg temp rise above ambient in normal operating conditions. That's a 2-4 % gain in power with ZERO pressure rise, because the runners of the manifold are pulling actual ambient temp air.

A stock LS-3 is Below 14.7 PSI after 4800RPM they drop from 14.5-14.6 to 14.10 PSI up to 5800 RPM.
People tend to look at peak numbers in a data log but not inside the actual log itself.

Your actual HP gain is the DA change inside the intake manifold + pressure.
That's about 13 HP from the pressure gained and 14hp gain from the DA change inside the manifold (385 Rear Wheel HP stock LS-3). That's a stone solid 27 rear wheel HP gain and this does not include any gains on the Dyno or from tuning etc...

Hope this helps VR Tech

 

great info. Thanks a lot

 

great advice. Thank you

 

what he said! 1/4 mile times don't lie

 

The gains from RAM AIR are more from the air being "Cooler" than the actual ramming effect.

In order to gain a single HP from "RAM AIR" your vehicle would need to be traveling faster than the airspeed at your throttle body. The air Speed at your throttle body at WOT will be well over 150MPH+ depending on RPM of course... this means you will see NO ramming effect until your vehicle exceeds the speed at which the air is traveling through the intake/throttle body. So the gains you get will be from the fact that the air is COOLER... not because its "RAMMING"

Pontiac coined the term "RAM AIR" as a successful marketing ploy. It worked... With aggressive looking hood scoops, they effectively introduced cooler air to the engine creating more HP while giving a more aggressive look to the vehicle and deceivingly credited those gains to the "RAM AIR" effect.

The intakes that flow the largest amount of unrestricted cool air with the least amount of turbulence will aid in making the most HP!

SPEED SAFE, AIR RAM

 

 

"The air Speed at your throttle body at WOT will be well over 150MPH+"

Actually, this is not correct for this application.
The problem is that most people/companies assume airflow/velocity values that are too high for the actual running engine. The air speed at the throttle body as measured at 5,800 RPM on a stock LS-3 is only about 37 MPH, its “NOT” some astronomical number.
This air speed correlates with mass airflow meter readings in LB’s/Min using a 4.0 ID tube 1-2 inches in front of the throttle body. If the air speed were 150 MPH the MAF sensor would spike and peak out of its HZ range around 2,500 RPM.

It’s important to note that, every engine is different based on HP/cubic inch, Intake manifold plenum volume, crank firing interval and inlet diameter. (The LS engines fire one cylinder per half crank rotation)

We probe into every intake/intake manifold in several key areas during on road testing. This is done to establish the peak MPH number we have to break to create Ram effect for a particular engine. This also produces a multitude of data, from Air temp to pressure drop, allowing us to establish the flow and thermal dynamic efficiency of a particular stock or modified system.
The old LS-6 Motor was 55 MPH, current Dodge Hemi engines are 43-45MPH.These are all similar engines with different inlet diameters and manifold plenum volumes.

The ability of a device or part to flow air as measured on a flow bench and the engines actual airflow requirements in dynamic running conditions are very different.

Hope this clears up the confusion on air speed required for Ram effect on an LS-3 engine.
VR Tech.

 

Agree. Cooler air is the key as unless you have blower or turbocharger, you can't get enough velocity to make that big of a difference. I'm not knocking Vararam, as many swear by them and they undoubtedly have an incremental improvement over the open shroud. But the open shroud gives volume and pure ambient air temp that comes in straight from the outside through the grill--at a good velocity directed upwards by the shape of the pushed back shroud. I remember the days of ram air back in the '60s, and had a Ram Air 2000 T/A which I took the baffles out of the scoops to improve volume and velocity. None of these were really "ram" air, just a way to get much cooler air into the intake. Vararam may indeed make more hp, but the 15 or so I got for $1.04 is hard to beat. If I was dragging my car and wanted the max increase, I would choose Vararam. But I don't and like I said for $400 the incremental increase isn't worth it for me.

 

I have an 11 Grand Sport. I seen many people talk about MODIFYING the shroud to get the cold air into the filter area.

Where is there a post that explains how this is accomplished and possible with the 11 C6 model??

Thanks

Bill

 

search "propped shroud"
I had a recent post detailing my method using 1/4-20 threaded rod, washers and nuts.

IIRC all C6 shrouds are similar enough that the year and model won't matter.

 

This may help.
http://forums.corvetteforum.com/c6-t...omparison.html

 

The shroud mod that people are referring to using the OEM LS-3 & LS-7 air-box is something we tested yrs ago. The reason you gain from this mod is , much like the old 4th gen F-Body ,is not the cool air. Its because GM has the front of the filter to close to the frame rail and most of the sides are blocked. By opening the shroud you have increased the filters frontal plenum volume allowing it to breath.
We always test FREE Mods like these on every vehicle. We do this just to make sure that we are well above any of those types of simple FREE Mods.
"Well above" being well over 25% + more airflow as measured through the MAF.


VR Tech

 

While the point you make is certainly accurate, you can't discount the cooler air that comes in directly from the front grill to the filter. The LS3 shroud box has virtually no provision for getting fresh air. The air inside it is almost stagnant and subject to increasing temperatures. The opened shroud brings in only outside air and constantly refreshes it. Every degree drop in IAT yields roughly .75 hp. A 20 degree drop, which has been shown to occur, gives you 15hp. Colder air is denser, and while the Vararam optimizes CAI and I have no doubt gives a greater increase for reasons you note, you can't discount what you get for free with the shroud pushback. As I noted about the Muscle Car era, this is proven performance increase without any "ramming" necessary.

 

the hp that a regular dd driver would get from "ram air" is about the same as you would get from installing those $300 spark plug wires. lol it's all snake oil. Cold air is what creates HP.... nitrous??

 

hmmmmm

 

Is it possible you could provide a link to the post where you describe your method for the shroud mod? I'd like to try the 'free' mod and see if there's any difference. I have a G-Tech meter, so I would go do a 0-60 run, then do your free mod, then quickly go back to same exact spot and do another 0-60 run before the weather changed.

EDIT: I searched and found this post here, is this it??? http://forums.corvetteforum.com/1584921626-post16.html

Many thanks, Dave F.



I will say that my buddy and I both had C5's a few years back, and we both installed Vararam CAI's and we did the G-Tech testing. We each shaved about 3/10 off our 0-60 times. But we did not do the testing on the exact same day as we did the Vararam installs, not sure how much difference that might have made. But I could feel the CAI in 'seat of the pants' performance.....

 

Yep, that's it. If you do back to back tests, I would suggest you do something more like 20-80 so you don't involve traction issues. I did controlled tests on a friend's '07 A6. He made 2 passes at 12.38 and then propped the shroud and he made 2 more at 12.20 & 12.21. He ran better with a Vararam, but it wasn't the same day.