I installed muffler bypass and cold air intake this weekend looking to add some power. The sound is good from both, alittle to much interior drown but not crazy. I did notice what I think is a big loss in low end and throttle response. Which one of these mods would be the greatest cause? I'm thinking it's the bypass pipes due to the refused back pressure???Any thoughts. Also wondering in a computer tune would help since the car is electronic throttle.

 

The intake could be causing it due to oil on the MAF, though that usually shows as a loss of a lot of power at about 4k rpm rather than a loss of low-end TQ. The bypass pipes very well could be causing it from the loss in back pressure. Is this a street driven car? Just wondering with those bypass pipes since they're awfully loud for the street. Getting a tune for parts always helps, but in this case there's no way to remedy the loss in back pressure with a tune. If I were you, I'd put the stock exhaust back on and drill out some holes via the tailpipes to get more sound. You don't get the weight savings of 40+ pounds, but you will get the sound.

FYI, those mods won't add any power to the car, only sound. There's really very little if any power to be had on the NA 996 short of forced induction. The intake usually causes a loss in power rather than a gain since the engine already gets more air than it can use. Which intake did you go with? Is it a true cold air with a full shroud?

 

Besides being very annoying, a muffler bypass can cause too much loss of back pressure causing the loss in power. The stock exhaust has been engineered, by actual automotive engineers (not internet advisers) to provide the optimum back pressure and power from the engine. Changing it drastically will cause a loss in power.

 

It is caused from the muffler bypass pipes. Gives you a great aggressive sound but you will lose on the low end torque. As for a tune,the 99's are cable throttle not electronic.

 

Like everyone else sound, most Bolt on's aren't worth it. Muffler by-passes, you will loss your low end torque but then make up a few horsepower on the top end. And most "Cold Air Intakes" are actually Warm Air Intakes, sucking in hot engine air killing power.

 

99 C2 is cable, 99 C4 is eThrottle.

 

The bypass, you are loosing too much back pressure.

 

How much power do you really gain aftermarket? Aftermarket hp gains show on dyno chart for real?

 

tune would def help

 

This is exactly what happens with go-fast bits on an na engine. Hard to face but our engines are pretty much maxed by the factory you want / need more HP the go turbo but on an na all those things that claim to add HP usually do so at expense of torque or by moving the power band into a fairly unusable range unless you are on a track.

 

I have a Fabspeed intake and exhaust bypass. I did not notice any difference, besides it revs quicker. I have no DYNO to give actual facts though. Personally, I am happy with them both. And I do not consider the Fabspeed intake to be a hot air intake. It gets plenty of air.

 

Like any car/aftermarket parts maker, charts and claims are always exaggerated. On the 996 NA engines they tend to be very exaggerated, more so than on most other cars I've owned and modded (which is every car I've owned).

An intake isn't considered "hot air" due to the volume of air received but due to the temperature of the air. Since your Fabspeed intake isn't well isolated from the engine bay, it's definitely a hot air intake. That panel that separates it from the engine still has those big gaps around the ends, and the filter itself is located at the end where it can suck in lots of hot engine air.

At lower speeds, there's very little airflow into the engine bay, so it's definitely costing you power due to intake charge temps that are significantly above ambient air temps. How much above will depend on the ambient air temps. At higher speeds, there is significantly more fresh air flowing into the engine compartment, but you're still going to be sucking in higher temp air than with the stock intake. However, it's not going to be a big enough difference in temps to really make any difference and cost you power.

The 996 NA motor already gets more air than it can use from the stock intake, so all you do with an aftermarket intake is cost yourself power and introduce possible MAF issues due to the oiled filter. Porsches MAFs are highly sensitive to oil. However, it does greatly improve the sound of the car, so if you can accept the loss of low-end power, zero change in top-end power, and few hundred dollar hit on your wallet in order to get a much better sound, then go for it!

This is what a true cold air intake looks like. This is the AEM intake on my Subaru STI. Notice that you can't see the filter element at all because it's down in the fender well isolated from the hot engine compartment air. It not only does this, but in addition draws from the same exact location as the stock intake does. It also includes a gasketed metal panel to seal the fender well from the engine compartment so no hot engine air can make it into the intake.

 

I feel horsepower numbers are meaningless! Its about what those numbers translate to real life. Before Turbocharging my 996, I had Softronics ECM Flash, K&N Cold Air Intake, Cat-Deletes and Afterhours Free Flow Mufflers, car sounded great and on paper I'm sure I had a 25hp+ increase but I'm real life it made no difference, my 1/4 mile was only dropped by 0.10 second and driving it i definitely noticed i lost my low end torque.

After wasting time with all the bolt ons, I finally tore my engine down to bare block and rebuilt it with a Turbocharger. Im blown away now! 470hp, so much low end torque that on my stock tires i do all wheel burn outs. Car handles get through the whole RPM band.

 

I really would like to add an Intake to improve throttle response. I have have done this on all my other sports cars and have always noticed a considereable improvement. I do have a concern about heat sink and degrading of performance on this car. While I love the eye candy of the Fabspeed Comp Intake, it certainly looks like it would suck in hot air. There are only two closed systems that I have seen the EVO and the cost prohibitive Carbonio. I have read mixed reviews on pretty much all of the intakes available. Any experience with the Evo or using a K&N drop in filter to improve throttle response with out hurting performance?

 

What is best drop in filter do you guys think?
Are most of them oiled and you mentioned bad for Maf?