locobob

Today myself and forum member/dyno owner TJ Wong set out to find the truth regarding C4 air intakes. We dyno tested 3 different air intakes on my Lingenfelter 368cid LT5. Tested today were: stock with paper element, stock with K&N element and a cut lid, and finally SLP's "claw" tri-cone filter design. All dyno pulls were made with starting coolant temps at 195 degrees F. Here are the results.

Stock with paper, two identical pulls: 477rwhp. Avg. peak HP 477

Stock with K&N and cut lid, three pulls: 471, 475, 480rwhp. Avg. peak HP 475.3

SLP tri-cone "claw", three pulls: 477, 478, 481rwhp. Avg. peak HP 478.7

It would appear that the naysayers are mostly correct about C4 air intakes, not much to be gained here. Both Tom and I were rather suprised with the results. We had expected to see some small but visible gains with the cut-lid and SLP, instead we got a bunch of tests with peak numbers being basically the same or well within normal dyno pull to pull variation. The SLP unit does seem to have a small advantage over the others but suprisingly it's in mid range power not peak (see dyno graph average power #'s).

cv67

Interesting you brought this up as there have been quite a few threads regarding the claw intake lately. Always good to see dyno proven results vs. speculation.

Jeffvette

SLP piece is nice in construction, but a lot of thought went into the design of the stock airbox.

So is it worth the 300?

And at what point can it not flow enough? 550? 600?

vader86

I would expect to see no gain whatsoever on a dyno.

It is in actual track results that most intake changes would show, as then the air is being forced into the intake.

But with the Claw's characteristics, I wouldnt expect gains with it anywhere, track or dyno.

CentralCoaster

None of these are ram air / cold air intakes.

The consensus is (was) that unblocking the filter will yield some HP.

vader86

I'm aware that they arent ram-air.

And I still say that unblocking the filter yields HP.

locobob

My thoughts going into this were:

1. Unblocking the filter would help i.e. cut lid, results = no measurable difference on the dyno. I wouldn't have believed it but those little slats cut into the air box lid can support 477rwhp at 7200rpms.

2. Clean K&N filter would outflow new paper by a small margin, results = no measurable difference.

3. SLP claw would gain some upper rpm power by being internally cleaner i.e. fewer/more gradual twists and turns, results = no measurable gain in peak HP but a gain of about 5 average HP and a small but noticeable hump in torque from 4000 to 5500rpm. This was supported by all three pulls with the SLP (indicating a trend) not just the one graph shown.

I plan on keeping the SLP. Besides having a very small average power advantage it's a nice quality piece and it being metal I can powder coat it to match my engine. Also it has good potential to be a true cold air intake by using a cut out fan shroud and some sheetmetal for a homemade scoop.

Anyhow I thought you guys would like to see some real test results on this subject seeing as it has been the matter of so much speculation.

93 ragtop

Robert, why does the AFR go from 12.5 to 13.3 on max readings between the k&n and the sllp? Oh, and thank you for taking the time to test and share this with us.

locobob

It's just a spike at the very beginning of the run, probably I was a little slower getting on the gas than on the other runs.

Alvin

I would have expected to see a little more gain than that... but your results don't nessisarly suprize me. I don't trust what is said on the interenet to much unless I've tried it personally or i've seen a subjective test like this done.

Corvette0096

Rob take that to the track and get some real world numbers...The DA yesterday at 2-3PM was in the -1300 range. Air Quality plays a big part in your other dyno day.

Alvin

It looks like they where all tested on the same day.

Corvette0096

I was referring to his dyno runs last year.

FD2BLK

That is just about what I would expect to see. I have often started I like my SLP but I did not think it would give any power over the cut lid. To be fair though unless you let the car cool down between runs it is not complaetly fair.

Jeffvette

All runs were done at 195 coolant temp.

And how often are you allowed to sit on the side of the road and wait until coolant temps get low before you romp on it.

FD2BLK

As long as it had the same oil and coolant temps then it is a fair test. As far as the second comment that was not the point. The point was if you roll in with good oil temp but a coolant temp of 177 then make several pulls and the last set of pulls was with the coolant temp of 225 it makes a big difference.

dgoodhue

On lesser output motor, the results don't surprise me that much, as the later air filters and boxes are pretty large. I sort of expect to see some difference given the output of given your HP though. IMO Mostly the Dyno results diffferences were probably due to the slight air fuel ratio changes. I wonder if you drove around for the ECM to learn and compensate would you have seen any difference (or if the chip was recalibrate for each air box).

CentralCoaster

Yeah, but I thought you were making a point that the filter location would give you either benefit you in terms of air temperature or air pressure.

It seems to me that on the highway, all these would suck in the same air temperature, and will all see the same pressure. Based on this, the low restriction filters should show the same % increase whether on the highway or not.

Lichen

Last year at a dyno session, we pulled off the Vortex crap and gained 10 rwhp.

CentralCoaster

This makes me want to do testing with and without the SLP ram air on my next trip to the drag strip, using the gtech to measure peak hp in gear.

I can easily get in 5 runs per hour with very consistent coolant temps.