LNF Intakes

Discussion in '2.0: LNF' started by cobalt123, May 3, 2011.

  1. cobalt123

    cobalt123 Platinum Member

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    ]I thought I would share my experiences with all the intakes I have either personally tested or done tuning on through data logs. I will start with the first intake I ever had and a very common one still the Dejon SRI. First of all, fitment is sub par as the coupler for the turbo is jerry rigged and the breather does not lock on. It is a very inexpensive intake compared to most others but you get what you paid for IMO. Data logs show a LTFT of -8 to -9 on my car and STFTs of -10 to +6 on the average. Even when tuned for the intake there was MAF turbulance evident especially under dynamic conditions. Driveability was fair when tuned except lots of bogging and misfires noticed especially as you roll into an off of the throttle. Sound wise this is the most agressive sounding intake I have ever heard on any car period. SRIs will be a lot louder in the car than CAIs due to intake location. Powerwise there were decent gains on the dyno 15-20 whp up top over the stock airbox tuned of course at 22 psi

    Next up is the AEM Intake. Fitment is excellent, the best of any intake I have ever seen. Cost is reasonable for the materials used ( 3.25" aluminum tubing, MAF extension harness, proper breather attachment). Drivability is not good at all at times due to compressor choke/surge observed on cold starts and also abrupt jerking and flutter dump as the throttle is realeased gradually especially when using the cruise control on slightly hilly roads. It causes LTFTs of +8.6 to +9.4 and STFTs of -5 to +7 so it does need some adjusting to get everything back to where it should be. If it were not for the surging issues due to the enormous silicome elbow and the MAF being placed way too close to the filter which causes turbulance issues at the MAF it would be a very good intake. The surging issue completely disappears if you remove the silicone elbow and run the factory elbow but, the factory elbow flows less so you have made the intake pretty much pointless from a performance standpoint. Sound is slighly louder than stock or about the same as the airbox mod. Power was again 15-20 whp up vs the stock airbox.

    Next is the factory airbox mod which uses a modded stock snorkel setup, a K&N drop in filter, and the infamous AEM silicone elbow. Well, fitment is well, almost like stock but coupling the modded snorkel to the airbox is tricky and the AEM elbow is actually about 1.0-1.5" longer than the stock elbow so it is difficult to remove the airbox lid to get to the filter. Trimming it a little helps some. Driveability is not that great untuned as the K&N causes turbulance at the MAF (Recurring theme here). Also, the cold start surging and abrupt shutter when letting off the throttle is still present and is just as bad as it is with the AEM intake tube. The LTFTs settle in at -3.2 to -5 in most cases (some have seen -7 LTFT) and the STFTs are between -13 and +6. The airbox mod actually causes just as much if not more skew than some intakes. Cost is appox $160 + $50 = $210 (about the same as a slightly used intake). Power gains are probably slightly less (probably 5-10 hp less) than some intakes but I have not dynoed it vs the stock intake with the same tune so I am unsure. ZZP showed 12-14 whp gains over the stock airbox.

    Due to popular demand the stock airbox with K&N drop in filter only. Cost is only ~$50. Installation is easy and takes approx 30 seconds and the fitment of the filter is just as good as stock. Drivability is OK but I noticed some bogging as I would stab the throttle. The Drop in filter skews the MAF about the same as the airbox mod at approx -3.2 to -5 LTFT and -12 to +6 STFT. There is no cold start surging or shutter with the drop in filter. Performance is a tad better at WOT vs the stock airfilter but the stock intake tube is almost as restrictive as the stock filter so the gains are likely 5-6 whp less than the airbox mod which was shown by ZZP to add ~12-14 whp up top over the stock intake. Even a drop in filter needs a tune for optimum drivability and performance. Side note : Removing the snorkel completely from the factory airbox is a bad idea because that snorkel acts as both a velocity stack (the bell shaped end helps funnel air) and also helps straighten the incoming air some before it hits the filter. Removing the snorkel while running a K&N Drop in filter causes a -7.2 LTFT and -17 to +10 STFTs because of lots of turbulance over the MAF. It is ok to mod your factory snorkel as described by ZZP in the airbox mod thread but I highly discourage removing the snorkel completely for the sake of responsiveness and overall performance. Sound is slightly louder than the stock airbox but not noticeable to me because my exhaust is loud.

    Now, we have Hahn's intake. Fitment varies depending on the age of the intake. Some of the older generation ones like mine do not have a locking breather attachment so I had to find a better way to secure the breather (a piece of 5/8" hose, two hose clamps and a slightly shortened version of my breather fitting for the AEM) . The MAF wiring loom has to be modified in order to reach the MAF in its new location (I have an extension harness from my AEM I used instead). Edit I got the stock MAF harness to reach by cutting a few of the fasteners that hold the main harness onto the engine. Drivability is very good compared to all other intake setups I have driven. It is smoother than the stock airbox even at idle and on cold starts which is a very refreshing change over my AEM intake. Finally no more surging! I cannot comment on the drivability of the intake untuned because Tom (I am Broke) was so kind as to send me his Hahn MAF tables he has been working on for at least a month now. :twothumbs I am working on dialing the MAF in the last 2-3% on my car right now. Performance feels about the same or slightly better than the AEM or Dejon intakes and this intake has proven to flow up to 38 lbs/min at 24 psi with the MAF corrected to within 1%. I have not dynoed the Hahn yet because it has been on my car since only last night LOL. There is some evidence of turbulance with the Hahn intake but it is not as bad as most of the other intakes I have logged. Sound s louder than the stock airbox and slightly louder than the airbox mod as I can hear the intake sometimes over my exhaust.

    Injen's intake I have not tested personally but Tofu, a member on here did some data logging and dyno testing of injen's intake. From his logs the LTFT was -6.2 to -7 when it settled and the STFTs varied from -12 to +5. He said the driveability was decent but it felt sliggish sometimes in the midrange. Dyno testing showed a 10-15 whp gain up top but significant losses of 15-20 wtrq in the midrange even when the MAF was tuned for the intake. Quality seems to be good and no one has reported any unusual issues with surging with Injen's intake.

    K&N's SRI is not out yet so no unbiased testing results are avaliable yet.

    Last but not least we have Clearimage's intakes. Some have had issues with the fitment of the coupler used. It was kinking and hiting both the AC line and the firewall as shown in a picture Steddy took. Steddy and PrincessTurbo are two that have had issues with the fitment of CIAs intake. Also according to PrincessTurbo that coupler supplied is very flimsy and collapses and kinks very easily. He ended up replacing it with a Vibrant reinforced elbow which solved the issue but cost him another $70. I tuned him for the intake and it was not that bad. It took 4-5 logs to get it perfect. The initial log showed a LTFT of -5.2 to -6 and STFT of -8 to +12. According to IsItFast he had some surging issues as well as a marked decrease in mileage until he had his MAF dialed in for the intake. Not sure if there is a marked power increase because I have never seen a before and after dyno. I have not seen any airflow improvements on PrincessTurbo's logs with the CIA CAI vs the stock airbox with a drop in filter. He said he did not feel any noticable difference comming from the stock airbox. I have always noticed a big difference especially in topend when switching from the stock airbox to an intake or vise versa.

    Turbulance over the MAF is a recurring theme here and the reason is simple. The factory MAF does not have a screen in front of it like most MAFs. The reason for this Laminar flow straightner is to ensure the airflow over the sensor is uniform and not turbulant because turbulance confuses the sensor skewing its readings. I believe the reason that there is no screen at the MAF is becauses of concerns that it could possibly be sucked into the turbo eventually. If the screen is properly secured it would not be an issue.

    In my opinion the perfect intake for the LNF would have a 3.25" intake tube made of Aluminum or Steel. It would have a separate MAF housing piece with a screen right in Front of the MAF to keep airflow readings consistant. The MAF housing's ID should be as close to the ID of the stock intake as possible to keep the fuel trims as close to stock as possible. The portion that couples to both the intake tube and the turbo would be made of aluminum or steel and would gradually taper in diameter from 3.25" to 2.5" and would use smooth long radius bends like the Hahn intake uses not a very sharp 90* bend like the AEM Elbow uses.
     

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