Air intake dyno results
Thread Starter
Drifting
Joined: Jun 2002
Posts: 1,491
Likes: 6
From: Portland Oregon
Air intake dyno results
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).
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).
Last edited by locobob; Jan 31, 2015 at 03:41 PM.
Race Director
Joined: May 2000
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From: No more yankee my wankee, the Donger is tired!
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?
So is it worth the 300?
And at what point can it not flow enough? 550? 600?
Team Owner
Joined: Sep 2001
Posts: 62,161
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
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.
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.
Team Owner
Joined: May 2002
Posts: 24,337
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by 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.
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.
The consensus is (was) that unblocking the filter will yield some HP.
Team Owner
Joined: Sep 2001
Posts: 62,161
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Originally Posted by CentralCoaster
None of these are ram air / cold air intakes.
The consensus is (was) that unblocking the filter will yield some HP.
The consensus is (was) that unblocking the filter will yield some HP.
And I still say that unblocking the filter yields HP.
Thread Starter
Drifting
Joined: Jun 2002
Posts: 1,491
Likes: 6
From: Portland Oregon
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.
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.
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Thread Starter
Drifting
Joined: Jun 2002
Posts: 1,491
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From: Portland Oregon
Originally Posted by 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. 
Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
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.
Drifting
Joined: May 2003
Posts: 1,730
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From: Charlotte NC
St. Jude Donor '05
Originally Posted by 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.
It looks like they where all tested on the same day.
Safety Car
Joined: Dec 2002
Posts: 3,655
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From: Charleston SC
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.
Race Director
Joined: May 2000
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From: No more yankee my wankee, the Donger is tired!
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.
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.
Safety Car
Joined: Dec 2002
Posts: 3,655
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From: Charleston SC
Originally Posted by 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.
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.
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.
Safety Car
Joined: Dec 1999
Posts: 4,691
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From: Framingham MA
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).
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by vader86
I'm aware that they arent ram-air.
And I still say that unblocking the filter yields HP.
And I still say that unblocking the filter yields HP.
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.
Melting Slicks
Joined: Nov 2002
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From: 1993 Quasar Blue 'vert Scottsdale AZ
Originally Posted by vader86
I'm aware that they arent ram-air.
And I still say that unblocking the filter yields HP.
And I still say that unblocking the filter yields HP.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
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.
I can easily get in 5 runs per hour with very consistent coolant temps.