Bimmer32

There are cool air intakes, KN filters, BB Exhaust, etc.

Based on the the total cost of parts and installation versus performance and mileage improvement, which one of these items are worth acquiring?

In other words, if the cool air intake cost about $200, how much hp or performance gain is ACTUALLY achieved at any RPM levels?

If the KN filter cost $50, what is the ACTUAL performance increase and is it still a good filter for the engine?

If the BB Exhaust is $XXX dollars installed, what is the ACTUAL performance increase and does it make your car sound like a boat?

The advertisement statement "increase UP to XX hp and XX torque" is vague at best. Will these items actual make the engine more efficient (mileage) and increase performance (when needed)?

What is really the difference between the mods versus a bigger displacement (from 4.4 to the new 4.8 enginge)?

I would like to know if it the mods are worth the ACTUAL performance increase to the engine (V8).

Thank you for your inputs.

znod

I don't have time to go into detail. But, be skeptical of most claims. I tend to believe the claims of Dinan--with even a grain of salt there. You could compare Dinan's claims with those of others assuming comparable parts exist to get a feel for what is likely to be true. Read Dinan's comments on dyno testing. I would go for the 4.8 engine and fewer, if any, mods.

znod

stream

I'm a skeptic when it comes to noticeable power increases from the types of mods you listed. And some can have adverse effects, like the K&N filter fouling the MAF.

If you want a sport exhaust get it for the sound, not the claimed power increase...or you can burn the attached file a few dozen times to a CD and play it in your car at high volume...
sport_exhaust.mp3

wolverine

I would agree with what everyone's said. Chiptuning, air intakes, exhaust may net you a few HP, but the performance gains will be modest, and expensive. If you really want to get some extra HP, a supercharger is probably your best bet, and probably the best buy in terms of real HP per dollar.

With a turbo engine like my 2.7T Audi, you could get some significant HP gains with a chip for under $1000. With BMW N/A engines it is really tough to get much HP inexpensively. As a general guideline, including labor, figure around $100 per real HP gain (eg, $1000 will get you 10 HP).

znod

I think your rule of thumb is a pretty good one especially if you are talking RWHP. Here is what I came up with on the "Mind Candy ..." thread noted above.

The final cost per flywheel [equivalent] HP [FEHP] is $2,650 / (37.4 + 3.7) = $2,650 / about 41 = about $65?but no spare in the car.

So, by my calculation, I estimate somewhat conservatively $2,650 net cost for about 41 FEHP (or about $65 per FEHP). In making the calculation, I took Dinan's and B&B's HP claims as given and used a conservative transformation of unsprung weight into sprung weight and a more or less standard transformation of sprung weight into FEHP. If we take, $2,650 / (.85(41)), then we get about $76 per RWHP. Both are short of your $100 figure, but, on the other hand the Dinan and B&B claims may be exagerated. I tend to put a bit more faith into what Dinan says, but B&B's claim is less than what manufacturers generally claim for BMW "mufflers."

m5lover

How much HP gains from your chip?Is chip and supercharge the same??

znod

How much HP gains from your chip?Is chip and supercharge the same??
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No, chipping has to do with reprograming a car's computer or replacing a chip in the computer. Supercharging is forced induction. Doing a supercharger is a warranty wrecker. Supercharging is somewhat like turbocharging. Both force one's air/fuel mixture into the combustion chamber under pressure--thus, more more mixture per unit of measure and more HP. Supercharging is expensive--say $10,000 for a high quality unit and installation. One might get 100 to 150 safe HP--at a cost of $100 per HP if 100 HP is gained. My numbers are just seat of the pants to give you an idea about supercharging. I could find some actual numbers later if you want. And, you could go to the Dinan site to check out some of their supercharger applications and costs. These days one is lucky to get a significant HP gain on BMWs from chipping. The chip providers are claiming 30 or 40 HP as I recall. There are current threads on this topic.

mehall2

Based on my 10 years of experience, modifying a 95 Trans Am from 275 Stock HP to 400HP, I would say most of the claims of HP gains are pretty sketchy. With the readily available Chassis Dyno's out there, there is an easy way to check the actual gains in modifications. The first Mods on my T/A was Cold Air Intake, Borla Exhaust. The Tuner claimed a 40 HP increase by adding these alone. The actual gain was more like 15hp. 5 from the intake, 10 from the exhaust. The exhaust was the best mod made to this car, as it improved the sound 100%. On a T/A, that is a good thing, on a 5 series, that is debatable.

The best bang for my buck was putting in 1.6 roller rockers, effectively raising the cam lift.

Remember, BMW's are already pumping out some pretty healthy HP numbers for their displacement. 325 out of 4.4 liters is very good. So, improving what is already there is going to be a difficult task at best. Remember, an engine is an air pump, the more air you can get it to process, the more HP you are going to make. Most all of the bolt on's that are available will make very modest gains, IMHO, unless you are talking about Supercharger or Turbocharger, which come with their own issues all together.

Buy the B & B or Remus for the sound, not the performance. To get real performance gains from your car, shave some significant weight, sprung and unsprung, change your cam profiles or bore out your motor to a larger dispacement or force more air in, through turbocharging or supercharging.

The old adage applies, especially to cars with Roundel, Speed Cost's Money, how fast do you want to go?

Regards, Michael

Bimmer32

Based on my 10 years of experience, modifying a 95 Trans Am from 275 Stock HP to 400HP, I would say most of the claims of HP gains are pretty sketchy. With the readily available Chassis Dyno's out there, there is an easy way to check the actual gains in modifications. The first Mods on my T/A was Cold Air Intake, Borla Exhaust. The Tuner claimed a 40 HP increase by adding these alone. The actual gain was more like 15hp. 5 from the intake, 10 from the exhaust. The exhaust was the best mod made to this car, as it improved the sound 100%. On a T/A, that is a good thing, on a 5 series, that is debatable.

The best bang for my buck was putting in 1.6 roller rockers, effectively raising the cam lift.

Remember, BMW's are already pumping out some pretty healthy HP numbers for their displacement. 325 out of 4.4 liters is very good. So, improving what is already there is going to be a difficult task at best. Remember, an engine is an air pump, the more air you can get it to process, the more HP you are going to make. Most all of the bolt on's that are available will make very modest gains, IMHO, unless you are talking about Supercharger or Turbocharger, which come with their own issues all together.

Buy the B & B or Remus for the sound, not the performance. To get real performance gains from your car, shave some significant weight, sprung and unsprung, change your cam profiles or bore out your motor to a larger dispacement or force more air in, through turbocharging or supercharging.

The old adage applies, especially to cars with Roundel, Speed Cost's Money, how fast do you want to go?

Regards, Michael
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Thank you, everyone, for the great information. I will look into those links and read more.

You make this forum great from your willingness to provide both technical and personal experience with the e60.