thesubfloor

After doing a comparison test a few months back between the K&N intake and a stock unit with an opened shroud (link shown below) I had the opportunity to do another test today but this time using the Vararam. Unfortunately the results were very disappointing despite having high hopes beforehand.

Although the DA was hovering at an insanely low -1000ft all day they only ran the 1/8th mile which kinda sucked since I was also gonna try and beat my 9.950 from last year. In the end it didn't really matter though as the track prep wasn't all that great requiring me to be very careful when launching the car.

Anyway, onto the results: I installed the Vararam last night and partially tuned it on my way to the track before finishing it up once I got there. After I made 6 passes and started getting consistent launches I decided to switch back to the stock unit. I dialed in the stock intake back in November so I was able to load that tune and be ready to go without any additional tuning.

The two runs shown below were made only 16 minutes apart, in the same lane, in very similar DAs (which meant the weather wasn't a factor) and almost identical 60fts (which meant that the traction was the same). I think the end results pretty much speak for themselves - the Vararam was good for only a .018 second ET gain and .35MPH - pretty disappointing given Vararam's claim of 3.5 tenths and 3.5MPH (and without tuning too).

While it is true that this test was only done on the 1/8th mile, I think it's still pretty obvious the results wouldn't be all that much better given the overall success or failure of a run is usually already determined by the 1/8th mile point. If however you don't believe that to be true and think the gains would be much greater in the second half of a 1/4 mile pass, even if we were very generous and the results were 3 times better it would only equate to an overall total gain of .072 seconds (4x.018) and 1.4MPH (4x.35).




While I'm not disputing that a Vararam will show improvements over a stock intake, the point of this thread is to show that you can get results which are only marginally less than Vararam's but without having to spend $469 in the process.

K&N Comparison thread:
http://forums.corvetteforum.com/c6-t...ts-inside.html

Polizzio

I bought a Vararam and installed on my 06 couple months back. Performance wise from seat of the pants is favorable, my man6 pulls so strong from 90 mph up. I also noticed after the install, engine has notably more low end torque, I can actually let out the clutch in 1st gear, zero throttle input, 600 rpm. Couldn't do that bone stock without killing the engine.

But I was severely disappointed with the unit fit and finish quality when I installed it. Major cracks/air leaks around air box to radiator shroud. I raised the car and sealed most with quality duct tape. I even pondered taking it right back out after, but I left it due to the increased performance, cold air to engine. When its time to clean the filter, I just may $hitcan it. No way would I recommend Vararam to any C6 owner because of the overall quality and fit in the car itself. From pics I see, the Honker is the way to go, no crappy fit to radiator shroud, gaps and air leaks bypassing radiator.
And yes I used the rubber seal molding they furnished in the kit.

Joe_G

Christopher I love the testing, and I'm sure not a Vararam poster boy, but with the weather that cold the Vararam won't prove its worth. Based on my observations, the benefit of the Vararam is that you never get the 150+ IAT's that folks get on 80 degree days while idling up in the lanes. I tend to run from memory about 10 over ambient in the lanes with my Vararam and down to 5 over by the end of the 1/8 through the end of the run.

As you know IAT's of 150 with a stock tune means about 12 degrees of timing lost. You get the IAT down to 80 or so and you've got the timing and the power back. It's a great mod for stock tune guys for that reason.

So before you think you wasted your money, re-test it this summer and give it a chance. I think it will help you, particularly those days were you have to idle a long time in the lanes in the summer, by giving you much more consistent IAT's throughout the run, including the launch.

Not that you need any more power! Nice launches on a slick track by the way, not many can get those consistent 1.4's. Top shelf.

Joe_G

p.s....what was your 0-60 times? You must have some of the best times on this board...

LS1LT1

Are you talking about the unit itself or simply about the aesthetics of the shroud after it's been cut?
That shroud can look a little rough after being cut to fit the unit I agree, but I think it's a rather small price to pay for the potential gains overall.
I mean, I really do hate the way the various small rocks, sand and cigarette butts look when stuck to my drag radials but I'm certainly not going to give up the 3 or 4 tenths they reduce my 1/4 mile times by just because of their appearance LOL.






That, as well as letting do it's thing on a full 1/4 mile where it should shine far more than it did in only the 1/8th.

Polizzio

Around the shroud. I purposely bought the pre-cut shroud with the Vararam kit, so I could keep my OEM shroud just in case. When installing, it was obvious there were serious gaps between the filter box and their cut shroud, some as large as 1", even using the supplied rubber molding. And any air leaking thru gaps doesn't see the radiator, tramp air flow just lost into engine compartment. Bad enough the VR airbox is partially impinging into the radiator duct airflow space. So I put her up on ramps and crawled below and sealed gaps with the best duct tape I could buy. And it works fine, and I do agree the performance advantages are really good, but the Calloway Honker does the same without all the gaps and tramp air leaks. Its ~ $100 more, but in retrospect I'd have paid the extra 100 for a better fitting product. And my airbox enclosure retaining clips needed tweaking right out of the box, sloppy assembly from the factory or whomever put it together. I'm pretty picky and am a technical/functional kind of guy, I would not buy the Vararam again thats all I'm saying. And when I do have to clean the filter element, I'm in for a job, my sealing tape and just the BS to get the element out. So imo only, if your thinking about a true cold air kit, buy the Honker if you like stuff that fits properly, well engineered.

Couple guys here have taken the VR off their vette and thrown it in the garbage, out of frustration. I almost did immediately after the install, seeing the end fit. But I did decide to give it a chance, and I will say the gain is good. Thats one thing Chevrolet engineers missed, why have the engine intaking hot underhood air and the resulting elevated IATs. From OEM design, they could have readily designed true atmospheric temp intake air, or cold air. They missed that one. But they didn't miss much I must say, my 06 impresses the hell out of me every time I drive it!

Mez

While I completely see your point, cooler air is more dense, so it provides more oxygen. More oxygen requires more fuel and that means more power.

Ignition advance by itself does not make more power. In theory, less advance is necessary at higher IAT to avoid knock and make the most power with the what oxygen and fuel.

Joe_G

I'm speaking of the stock IAT spark timing reduction table, as seen below. Regardless of air temp, when you reduce timing by 12 degrees, approximately 1/2 of commanded, you lose a lot of power. By providing significantly cooler air, particularly in the lanes where the car is not moving, and thus give the car up to 12 degrees more timing, you give the car a lot more power.

On really cold days or nights, when you don't have to wait to run, there is no such effect as the stock IAT spark table doesn't come into play.

That is why the fastest bone stock guys do it on great DA days, and make the run by starting and heading right up for the run before the engine compartment has a chance to heat the IAT air. In real world conditions, the vararam makes the car much more consistent particularly for bracket racing, as your time in the lanes waiting to run can vary widely and it only takes a few minutes in the lanes to heat up IAT to 150+ with the stock intake based on my scans of friends cars.. Ask jpee how inconsistent his car was before the vararam.

I hope I am more clear on this post?

OBSSSD

...and it fits like garbage needing frequent cleanings from all the stuff it ingests - just make sure you get duct tape when you order one

Joe_G

Once again I am not a poster boy but I have NEVER had anything get past my Vararam in 4 years of daily driving use. Mine seals perfectly.

And I cut my shroud myself and it is a nice fit around the unit.

Craigster05

Marc has a good point that I agree with. All of the logging and testing I did with the Vararam vs OEM, with, without the front plate, 1/4mis, high speed mile runs etc all pointed out to me, that the higher the MPH, the more of a significant difference you could see in the log files...in fact, all else being equal (temps, alt, etc) the gains and measurable differences were always most noticeable the more you climbed past 100mph....then it always showed exponentially higher ram air benefits the faster you went.

I think Chris is also just proving out his opinion here that Vararam may not be for everybody, especially to a casual driver or part time street banger with an LS3 that might expect miracles for the approx $500 investment that comes with the unit.

Either way you look at it, intakes are just one of many building blocks to a great performing car....and as I still one of Spin's mantras to me...5hp+5hp+5hp+5hp still equals 20hp, and if all those little gains get you thru the traps even a fraction of a second before the other guy, you still win....so do all the little stuff you can.

5knives

This is very interesting. Proponents of the VR have always said it's gains far outweigh the disappointing aesthetic issues some owners have as well as their fit & finish complaints. I forgot who it was on here that supposedly gained .3 from just the VR? I believe he was mildly modded too. I wonder if the VR's potential changes with the amount of mods the engine has? Anyway, I agree with the others about testing it in different weather conditions and full 1/4 passes before making a definitive judgement. I await further data.

ps: Don't you have an LS7 swap? Are you using the stock LS7 intake or an LS2? Perhaps the VR doesn't offer as much of an advantage over the LS7/3 style air intake as it does over the LS2?

Joe_G

IMHO, I think the vararam has the most benefit for the basically stock folks without a tune, as it prevents the intrusive IAT spark reduction table from kicking in. So for them, they get a sop benefit that is real, particularly in warm weather and particularly from a dig as they have a lot more timing.

Tuned folks that have the IAT spark table reduced won't see as dramatic effect, and on cold days, even the stock intake doesn't get that hot.

da vette guy

First,thanks for taking the time and effort to do this test. but i wonder if the big claims to CAI of all types is that they are installed on untuned mostly stock cars that normally run very rich on wide open throttle and they lean the air-fuel quite a bit allowing big gains on the dyno and track when first tested. they are telling the truth but once the ECMs adaptive learning stategy compensates the gains are not nearly as impressive. what do you think?

Swampthang

I guess I must have been lucky. I had no trouble installing mine and if fits well. No complaints, so far.

Joe_G

I don't think the factory intake is an air restriction...evidenced by the fact that map values are still high (at or close to 100) with factory intake, about equal to the vararam, for a mostly stock engine. I understand from my buddy gtodoug that they do become a restriction showing up around 480 rwhp or so.So I don't think more air is getting in. You'd need more air to be getting in to lean out the commanded open loop WOT fueling.

I think the benefit is just cooler air so more timing is being allowed.

Man I am on a tear today! I gotta give it a rest.

Mez

Oh, you are clear. And, yes, high IAT result in less power and less ignition advance.

But why?

The primary reason for the decline in power is hot air is thinner so it contains less oxygen to burn.

Less ignition advance is necessary to avoid premature ignition (knock) as a result of the hotter air/fuel mixture.

Perhaps the stock PCM IAT table is conservative as I have seen people cut this in half and still run fine.

Mike's LS3

I think this "ram affect" is over rated. The stock LS3 will trap the 1/4 at 115-117 mph. Chris's vette, modded of course, was trapping 107 and 108 mph in the 1/8th mile and the performance differences between the two air intakes at that speed were minimal. I do not think another 10-15 mph trap speed would show significant differences between the two air intakes. Now if your talking forced induction that's another story.

Our goal should be keeping the IAT's as low as possible to preserve power.

Joe_G

As we know the hotter the mixture the more prone it is to detonation, thus less timing is needed or desirable, thus the table. The vararam keeps the mixture from ever getting up to 150 which it can do with the stock intake, so I guess that is the true value.

Vararam's advantage over other intakes is that it doesn't draw from the radiator cavity which is hot at idle when not moving, if I am remembering properly my scans of my friends' cars so equipped.

Joe_G

I agree with this. There have been smarter people than me posting in other threads on the really high speeds needed for a true ram air.

Perhaps there is ram air at 185 mph....but countering that theory, my map per my scan at 170-185 mph was actually 98 kPa at that speed, indicating no ram air effect. It is 100 kpa doing quarter mile events. Perhaps I should have taken my filter out at that speed.