Installed K&N SRI with heat shield enclosure

[hyperpm]

Installed K&N SRI: Now with DYNO results on pg.2

Purchase price: $280 shipped off eBay.

Quality: Very high and every piece fit snug like a glove as if OEM especially heat shield enclosure.

Install: Easy

Performance: Smoother powerband and appears it did a lot in mid to upper rpm range. Compared to Cobb SRI, I like this better. Cobb had big hp and tq increases at 3200 rpm but quickly died down up top(dynoed 250hp/285tq peak but biggest increases were +20 hp/+30 tq gains down low at 3250rpm). Since Cobb SRI did have big gains down low I would just spin wheels and or tug when in tighter turns. I prefer smoother and gradual power delivery from K&N so "might" not be as powerfull with Cobb SRI but I'd rather have smoother power delivery. I'll dyno one of these days but who knows maybe this makes more power.

Induction noise: Not as loud as Cobb SRI but still very noticeable.

Air straighteners: It has none. Smoother revving compared to OEM and Cobb which has these things. No CELs either.

 

[Sport6]

Thanks for the info! Any pics?

Do you have a dashhawk or anything similar to check the fuel trims?

 

[CWPspeed3]

Nice write up, pretty interesting. do you have any pictures of it installed?

 

[Silver Ecstasy]

I'm kinda curious...they're both just piping with a filter at the end. How would one make once of a difference over the other?

 

[hyperpm]

Cobb SRI dyno:

I'll post K&N dyno sometime next week.

 

[hyperpm]

I'm kinda curious...they're both just piping with a filter at the end. How would one make once of a difference over the other?

Cobb SRI silicone piping actually gets distorted the way it sits atop other hoses so "oblongish" instead of perfect tube even with bracket to keep in place installed correctly. It's shorter and larger in diameter from filter end then tapers down smaller. K&N aluminum pipe longer, "appears" larger in diameter, and same diameter throughout. Pipe also appears powdercoated. I'm not sure if these caused the difference in power delivery but we'll see what the dyno says next week.

EDIT: Just got home and compared the the two and Cobb piping actually larger from filter end side compared to K&N.

 

[hyperpm]

Thanks for the info! Any pics?

Do you have a dashhawk or anything similar to check the fuel trims?

I'll post pics later but no dashhawk. It's my daily so only thing I'm modding is the intake. I'll post dyno next week with A/F.

 

[MSMS3]

I've always liked K&N products. Build quality and attention to detail are always first class. I run K&N intakes on several other vehicles and have for many years. Currently their CAI on one, pancake type on top of carb on another (off road use), and a drop in on my wife's car. The filters last forever and are very easy to clean. Most people clean them way too often (about once ever 50,000 miles is all that is needed unless the vehicle is operated in very dusty dirt road and off road conditions.

I went with the MSCAI because K&N did not have its product out and because the MSCAI and AEM (identical) CAI's are true cold air intakes pulling from in front of the left front fender through slots to the outside there.

I'm a bit disappointed that the K&N for our cars did not go that route. It is not a CAI, but rather a SRI with a heat shield. Hopefully the shield will help protect against heat soak. It gets very hot under the hood of a turbocharged car.

This K&N intake should produce very nice gains and will last forever. As with another poster, I think that OP's "butt dyno" may be playing tricks, or that his ECU has not adjusted yet. There really should be no difference in performance from one good SRI to another, unless one is defective in some manner. A longer tube should not make any difference, IMHO. It's not like the tube is empty -- regardless of length to the filter, the tube is full of the same air that's otherwise inside the engine compartment and can only flow its CFM limit.

I hope K&N did their homework, like they typically do, and have matched the diameter of the tube to the same diameter as the stock MAF housing. Changing that will definitely mess up the MAF readings being sent to the ECU. Other manufacturers have learned this the hard way early on in the life cycle of our model. The absence of an air straightener raises my eyebrow. Hopefully their design resulted in avoiding turbulance in the air column as it crosses the MAF sensor. That's another cause of ECU misreading and AFR errors.

OP: Excellent choice. Bullet proof. Great gains. Don't expect it, over the long term, to perform much differently than the Cobb SRI, IMHO, except for the possible benefits from the shield. It's still basically the same air column flowing at the same rate.

 

[hyperpm]

how long does our ecu actually "learn" new mod?

 

[hyperpm]

sorry for the crappy cell pics but you get the idea:

 

[Darth Vader]

Respectfully disagree with MSMS3. Length and shape changes, even small ones, of a pipe with a fluid column inside of it can have drastically different effects.

I have an example from the aerospace world. Tiny changes to the shape of an exhaust stack (the most minimal piece of flow-directing piping one can find on any engine) on an IC aircraft engine can have huge power effects plus radically alter the jet thrust produced by the exhaust. And by tiny changes, I mean like less than an inch in overall length or necking down or up the diameter by 1/4 inch.

The intake of a car is no different. The reason most manufacturers of similar product get similar results is because the maths are the same, they are basing their calculations off the same engine and the end results are they come up with are similar; not because small changes here don't have effects.

 

[leadf00t]

Thought I'd chime in on this one. If you search K&N Sri, I have posted pictures of it before. I have a dashhawk, and my ltft,s are fine. They are around zero most of the time. Idle trims can be -9ish until the car warms up, and then they come down to -7's. driving they are either 0, or -2's. Never on the lean side. I have had the K&N on my car since April, and no cel's.

 

[MSMS3]

Respectfully disagree with MSMS3. Length and shape changes, even small ones, of a pipe with a fluid column inside of it can have drastically different effects.

I have an example from the aerospace world. Tiny changes to the shape of an exhaust stack (the most minimal piece of flow-directing piping one can find on any engine) on an IC aircraft engine can have huge power effects plus radically alter the jet thrust produced by the exhaust. And by tiny changes, I mean like less than an inch in overall length or necking down or up the diameter by 1/4 inch.

The intake of a car is no different. The reason most manufacturers of similar product get similar results is because the maths are the same, they are basing their calculations off the same engine and the end results are they come up with are similar; not because small changes here don't have effects.

I see your point and agree with what you are saying. Shape very much matters, changes in diameter and the presence or absence of curves and how sharp they may be matter also.

I was addressing the more limited issue that just because the intake tubing is longer or shorter, in and of itself, ought not make any difference in performance of an intake, assuming that the diameter is the same, CFM flow rate is the same and there has been no introduction of turbulence before the air column passes through the MAF sensor.

 

[Darth Vader]

Oh, but the length does matter, very much so, as in my exhaust stack example, or in a trombone. The cfm of the tube in the trombone doesn't change but sound certainly does.

This is why tuned-length velocity stacks work on cars and now bikes, too. On bikes these days, Yamaha R1 in particular, an ecu controlled variable-length velocity stack is there to tune the power output of its highly-strung engine. A lengthier stack is used to tune for more midrange power, and a shorter stack length is used to tune for hi rpm power. It's a brilliantly complex answer to a question that could be solved more easily but, that's the wonder of modern ecu computing power.

 

[SallySpeed3]

Cobb SRI dyno:

I'll post K&N dyno sometime next week.

Is that for real? HP gains of 25 hp? Cobb only claims 11 hp on their website.

 

[Darth Vader]

Cobb tested using an eddy current dyno, which is far more conservative (and realistic) than the big D and other similar units.

 

[hyperpm]

Is that for real? HP gains of 25 hp? Cobb only claims 11 hp on their website.

lol yes. actually red graph shows what Cobb claims at peak but this was with fan on radiator. blue graph is with fan pointed at intercooler. now look at difference from stock at 3200 rpm.

 

[MSMS3]

Oh, but the length does matter, very much so, as in my exhaust stack example, or in a trombone. The cfm of the tube in the trombone doesn't change but sound certainly does.

This is why tuned-length velocity stacks work on cars and now bikes, too. On bikes these days, Yamaha R1 in particular, an ecu controlled variable-length velocity stack is there to tune the power output of its highly-strung engine. A lengthier stack is used to tune for more midrange power, and a shorter stack length is used to tune for hi rpm power. It's a brilliantly complex answer to a question that could be solved more easily but, that's the wonder of modern ecu computing power.

I appreciate this tuned-length velocity stack principle on normally aspirated engines. Does it make any difference on a forced induction engine with direct fuel injection? I would think that the passage from MAF through compressor side of turbo, compression (boost) and heat changes, then the long intercooler pathway before actually getting the cooled down pressurzed charge to the cylinder head might negate any effect. It seems to me (perhaps mistaken) is that all the engine is going to care about regarding the non-pressurized side of the intake system is an accurate MAF sensor reading and the cfm flow going into the compressor side of the turbo.

 

[hyperpm]

Well guys it looks like my butt dyno assesment was accurate after all where power moved up in the powerband. Same dyno and same operator in 4th gear.

K&N SRI: 255 whp and 272 wtq

Cobb SRI: 250 whp and 285 wtq
Stock: 225 whp and 257 wtq

K&N peak torque of 272 was higher in powerband(4400rpm) than Cobb where peak torque of 285 was at 3200rpm. I prefer K&N powerband better and now more fun to drive

 

[MSMS3]

I interpret these two sheets a little differently. The scales are not the same on those two dyno sheets. The Cobb sheet had a hp scale to 300 while the K&N has the top line at 275. Because torque scales are the same on both, going to 300, this makes the K&N scale look more vertical for hp and exaggerates the differences.

What really troubles me is the alarming loss of 100 pounds of torque on the new run down at 3000 rpm or so and about a 25 hp loss, if I'm able to read this right. This causes me to question the operator and setup. Maybe he did a gradual roll up and did not capture all the potential power at lower rpm?

I don't think that a change in intake would reliably produce that huge loss in power at that point. So, with respect, I'm not prepared to say what this new dyno run means one way or the other. Holding torque better up high would be a good thing, but I can't accept this until I understand what happened down at 3,000 rpm where these engines are torque monsters.

Is this just me?