# Performance Rules of Thumb



## Malachi (Sep 30, 2003)

These are a couple of rules of thumb you may want to consider when doing a cost-benefits analysis for your E39.

1) Pounds: for every +/- 100 lbs you get an equivalent +/- 7 HP

2) HP=>ET: An increase of 10 HP will reduce your 1/4 mile ET by .15 seconds

I used a couple of different programs/calculators for this. This is not an exact science but I believe will give you an idea of your bang for your buck.

Just thought I would share them.


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## DanB (Feb 20, 2002)

Very interesting... Let's revisit some of the things which would help us shave weight, while retaining the luxury aspect of the car...

-Carbon Fiber hood, trunk lid, front fenders. These parts wouldn't be particularly hard to make, though the trunk lid has a lot going on inside of it, and would probably be the hardest part. I imagine this would save 150 lbs or so. Beastpower is working on the hood...

-Carbon Fiber sunroof replacement ~ 20 lbs saved

-Spare tire delete, replace with M-mobility ~ 35 lbs saved

-Dinan, or other 17 lb lightweight wheels ~ 30 lbs (sprung?) weight saved

-Exhaust system replaced ~ 50 lbs (though arguably lessens the "luxury" aspect)

-Carbon Fiber driveshaft ~ 20 lbs (stock is 26 lbs)

-Misc Carbon Fiber pieces (intake  , valve covers, etc) ~ 20 lbs

So with all this, you could save maybe 325 lbs

-----------------------------------

Items which would detract from luxury, but would leave the car functional;

-Composite seats ~ 70 lbs
-AC system removal ~ 50 lbs
-lightweight flywheel ~ 15 lbs

So there's another 125 lbs

So you can shave ~ 480-500 lbs off the weight of an E39 540i/528i. That's good for 35 HP equivalent/.52 seconds off your 1/4 mile, not to mention an increase in handling. 

What do you think?

-DanB


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## Malachi (Sep 30, 2003)

DanB said:


> Very interesting... Let's revisit some of the things which would help us shave weight, while retaining the luxury aspect of the car...
> 
> So with all this, you could save maybe 325 lbs
> 
> ...


 :eeps:

I don't know all the cost associated with that, and how much increase in handling one would get, but it seems to me that it would be a lot easier and cost effective to get NOS and add 40 hp safely.

What do you think?


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## kowached (Jun 20, 2003)

I think that Dan is is counting some items too lightly.

I'm not disagreeing with your weights, I just beleive that the 3 items below will have a greater effect than just the total weight saved. They are rotational driveline components and reducing their weight will reduce rotational mass in the driveline, providing HP benefits far greater than the overall reduction in total weight of the car.
-Carbon Fiber driveshaft ~ 20 lbs (stock is 26 lbs)
-lightweight flywheel ~ 15 lbs
-Dinan, or other 17 lb lightweight wheels ~ 30 lbs (sprung?) weight saved

I also think that the reducing unsprung mass by going with a lighter tire/wheel combination can make a tremendous handling difference in addition to reducing rotational mass at the rear (drive) wheels.


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## JetBlack330i (Feb 8, 2002)

I thought a BMW is all about balance between luxury and performance. 
Your suggestions would take the luxury and comfort away in favor of performance.
You still won't beat a Camaro costing a third of your 5 series. What are you trying to accomplish?


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## DanB (Feb 20, 2002)

Yeah, I've heard the same about those items. I'm a bit rusty on my sprung vs. unsprung vs. rotational weight savings physics, but I didn't want to say something in my post that I pulled out of my arse.

You could add to the list with Carbon Fiber half shafts and ceramic brake rotors I suppose. 



kowached said:


> I think that Dan is is counting some items too lightly.
> 
> I'm not disagreeing with your weights, I just beleive that the 3 items below will have a greater effect than just the total weight saved. They are rotational driveline components and reducing their weight will reduce rotational mass in the driveline, providing HP benefits far greater than the overall reduction in total weight of the car.
> -Carbon Fiber driveshaft ~ 20 lbs (stock is 26 lbs)
> ...


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## DanB (Feb 20, 2002)

JetBlack330i said:


> I thought a BMW is all about balance between luxury and performance.
> Your suggestions would take the luxury and comfort away in favor of performance.
> You still won't beat a Camaro costing a third of your 5 series. What are you trying to accomplish?


hehe, I would. :eeps: 

But seriously, not all of those items would take away any of the luxury of the car. Carbon Fiber hood/trunk/fenders, driveshaft, spare tire delete - if made from solid and quality parts - would not in any way detract from the luxury of the car. Carbon Fiber can be painted, and the M5 comes with M-Mobility.

The sunroof would (I suppose) take away from the luxury aspect, though things like the wheels and the exhaust are things that many do anyway to enhance the performance of their E39s.

-DanB


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## kowached (Jun 20, 2003)

JetBlack330i said:


> I thought a BMW is all about balance between luxury and performance.
> Your suggestions would take the luxury and comfort away in favor of performance.
> You still won't beat a Camaro costing a third of your 5 series. What are you trying to accomplish?


Sure BMW builds a car with a balance of luxury and performance. They decide on the formula for the balance by what the majority of their buyers are looking for, I'm totally pleased with my 540iA Sport, but that doesn't mean that there are not people that want to take one aspect of the car a step further in one direction or the other.


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## Malachi (Sep 30, 2003)

DanB said:


> hehe, I would. :eeps:
> 
> But seriously, not all of those items would take away any of the luxury of the car. Carbon Fiber hood/trunk/fenders, driveshaft, spare tire delete - if made from solid and quality parts - would not in any way detract from the luxury of the car. Carbon Fiber can be painted, and the M5 comes with M-Mobility.
> 
> ...


Anyone know how much our hoods weigh and how much a carbon fiber hood would weigh?

That would be one mod worth looking at because it is taking away weight on the front end where it is needed most to get that 50/50 balance.

Reducing weight on the back end (exhaust) takes the current 52/48 balance and makes it worse.


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## DanB (Feb 20, 2002)

Malachi said:


> Anyone know how much our hoods weigh and how much a carbon fiber hood would weigh?
> 
> That would be one mod worth looking at because it is taking away weight on the front end where it is needed most to get that 50/50 balance.
> 
> Reducing weight on the back end (exhaust) takes the current 52/48 balance and makes it worse.


Stock hood: 50 lbs w/sound silencing material (15 lbs CF)
trunk: 28.2 lbs (8 lbs CF)
sunroof glass: 16.1 lbs (2 lbs CF)
front fender (ea): ~ 20 lbs (6 lbs CF ea)

The first 3 are from ETK weights, the last one is an estimation from when I've handled a front fender.

My estimates for CF weight are based on my involvement in the production of the stuff. If it's 100% pure carbon with no fiberglass, you can achieve said weights. Now that I look more closely, there's really only about 100 lbs savings (not 150).

-DanB


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## bmw540i (Mar 30, 2003)

DanB said:


> Stock hood: 50 lbs w/sound silencing material (15 lbs CF)
> trunk: 28.2 lbs (8 lbs CF)
> sunroof glass: 16.1 lbs (2 lbs CF)
> front fender (ea): ~ 20 lbs (6 lbs CF ea)
> ...


get some BBS RGR and youre set to go.


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## Malachi (Sep 30, 2003)

DanB said:


> Stock hood: 50 lbs w/sound silencing material (15 lbs CF)
> trunk: 28.2 lbs (8 lbs CF)
> sunroof glass: 16.1 lbs (2 lbs CF)
> front fender (ea): ~ 20 lbs (6 lbs CF ea)
> ...


Great info Dan :thumbup:

In theory E39 540i would have to lose about 79 lbs to get to the magical 50/50 (I really don't know how much that will improve handling but, I guess thats another discussion). The CF hood and fenders would lessen the front end by 63 lbs (35+14+14) and get us an equivalent of 4.4 hp or .07 seconds in the 1/4 mile ET for the low price of ____________?

Again, great info Dan, I appreciate the data.


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## bmw540i (Mar 30, 2003)

does anyone know where we can purchase CF fenders and so on i know Beastpower is working on a CF hood but what about fenders and trunk.


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## DanB (Feb 20, 2002)

Malachi said:


> Great info Dan :thumbup:
> 
> In theory E39 540i would have to lose about 79 lbs to get to the magical 50/50 (I really don't know how much that will improve handling but, I guess thats another discussion). The CF hood and fenders would lessen the front end by 63 lbs (35+14+14) and get us an equivalent of 4.4 hp or .07 seconds in the 1/4 mile ET for the low price of ____________?
> 
> Again, great info Dan, I appreciate the data.


Get ready for the long version...

To start, a well made carbon fiber hood will require a $5000.00 mold. Mold costs vary by the person who makes 'em, and someone with skill is needed to make a mold that will produce a hood nothing short of art. I guess you could also CNC an aluminum mold, though it would weigh a ton - and would likely cost more. The actual material involved - if 100% carbon fiber - would probably be $500 alone (4.75/sq foot for pre-preg carbon fiber, assuming 5 layers of carbon used and a hood which is 4.5x5 feet).

The layup itself would take several hours by a very skilled person so that the bias was completely straight, and so that there were no pinholes in the piece. After this, the whole thing would have to be sealed in a vacuum bag to provide compaction, and cured in an autoclave (which heats up while providing constant vacuum). Compaction essentially squishes the carbon fiber against the mold, and forces the resin to flow in the direction of the mold - forming a beautiful surface. If the person making the piece is skilled, the piece will only need to be buffed a little to look like this. If not, the whole hood will need to be sanded down and sprayed with an acrylic clearcoat to achieve the same finish. (which adds weight). After the piece is cured in the autoclave, it is taken out, popped out of the mold, and trimmed to the exact size it needs to be.

A secondary bonding process will be needed to incorporate the mounting points for the OEM hinge and latch.

So taking into account a $5,000.00 mold, 8 hours or so to lay the piece up and finish it, and profit for the shop, you're realistically looking at a $2,000 - $2500.00 price tag on a well made lightweight carbon fiber hood, $1500-$2,000 for fenders, and about the same for a trunk. This is assuming a run of 50 of each product to ammortize the cost of the mold, which puts the manufacturer over the fence for well over $150,000 to bring the product to market with an inventory. Of course, you could do batches of 10 at a time for 17K/batch.

You might be asking why you see "Carbon Fiber" hoods for $200-$500? It's because they are made with several layers of fiberglass, and maybe one layer of actual carbon fiber which is not pre-preg (pre impregnated with resin). After the layers of fiberglass are applied (cheap, heavy, and known as a "filler" material in the composites industry) they use a wet-layup process on the one layer of carbon fiber. This means they lay a raw sheet of carbon fiber (has the consistency of cloth) onto the fiberglass, and paintbrush resin into it. The whole thing is put in an oven and baked (not using any compaction). This method produces a heavy hood which is often as heavy as stock, and because of the resin they lay it up with - the piece will have "paint strokes" and will likely rapidly turn yellow with UV exposure.

Below are more examples of good carbon fiber which is made using pre-preg carbon fiber in an autoclaved process...

56K warning! Carbon Fiber intake

56K WARNING!!! Ducati Fender

Another 56K warning! This is a Ducati rear fender.


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## Malachi (Sep 30, 2003)

DanB said:


> Get ready for the long version...


Wow thanks Dan :thumbup: :thumbup: :thumbup:

Just about everything I ever wanted to know!

Can CF be painted to match the car's original color?


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## JetBlack330i (Feb 8, 2002)

kowached said:


> Sure BMW builds a car with a balance of luxury and performance. They decide on the formula for the balance by what the majority of their buyers are looking for, I'm totally pleased with my 540iA Sport, but that doesn't mean that there are not people that want to take one aspect of the car a step further in one direction or the other.


Sure those people exist. I am one of them.
We can wish, talk and dream about it all they want. But when it comes down to actually doing it, one soon realizes that it's not worth it.
And by the time we are done with the CF we still can't beat a Camaro that was built with 1/3 of the budget.
Oh, I'm all for light weight wheels and even removing the sunroof, but putting race seats and lightweight flywheel does take away from comfort.


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## LmtdSlip (May 28, 2003)

JetBlack330i said:


> I thought a BMW is all about balance between luxury and performance.
> Your suggestions would take the luxury and comfort away in favor of performance.
> You still won't beat a Camaro costing a third of your 5 series. What are you trying to accomplish?


That may be the goal now days...but the old 3 series and coupes were way more about performance than fake luxuary items like rain sensing wipers, cup holders, automatic butt wipers, etc.

When did BMW start thinking it was a good idea to start benchmarking Lexus?


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## flashinthepan (Jul 25, 2003)

I like the extras - and the current cars have better factory performance specs.

But,

I also am a huge fan of the older cars too.

BMW has to be progressive, the masses have come to expect auto evrything, buying a crank window in todays markey for a 40k car just aint right.

:dunno:


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## Ågent99 (Jan 7, 2002)

JetBlack330i said:


> Sure those people exist. I am one of them.
> We can wish, talk and dream about it all they want. But when it comes down to actually doing it, one soon realizes that it's not worth it.
> And by the time we are done with the CF we still can't beat a Camaro that was built with 1/3 of the budget.
> Oh, I'm all for light weight wheels and even removing the sunroof, but putting race seats and lightweight flywheel does take away from comfort.


While the teenager in me *would* like to beat that Camaro, I don't own a BMW so that I can beat the Camaro. I own it for the level of performance it provides me and my family. It is fun to whip around when I am alone yet is comfortable and safe enough to take a 4200 mile trip in with my family and get 30 mpg to boot! 

Sure, if I had money to throw away, I am sure I could build a majorly expensive BMW to trash Camaros/Mustangs all day long but in the end, I'd just buy a Camaro or Mustang if I was interested in beating them. :bigpimp:

Chris


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## DanB (Feb 20, 2002)

Malachi said:


> Wow thanks Dan :thumbup: :thumbup: :thumbup:
> 
> Just about everything I ever wanted to know!
> 
> Can CF be painted to match the car's original color?


Absolutely, though it needs to be sanded down to be able to use a primer that will adhere to the surface.

-DanB


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## humanoid (Mar 31, 2002)

You forgot one thing!

If I could drop 100 lbs of weight off my arse then, I could get the mini beast down about 600lbs :bigpimp:


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## Aye Chingow! (Oct 6, 2003)

JetBlack330i said:


> I thought a BMW is all about balance between luxury and performance.
> Your suggestions would take the luxury and comfort away in favor of performance.
> You still won't beat a Camaro costing a third of your 5 series. What are you trying to accomplish?


Your comment about not beating a Camaro got me thinking. Only because I have beat Camaros (and even owned a Z28 once). So I went hunting around the web for 0-60 and 1/4 mile times of the e39 540 and a Camaro Z28 SS and the numbers pretty much hover around 5.5 sec 0-60 and 14 sec 1/4 mile for the 540 and 5.2 sec 0-60 and 13.6 sec 1/4 mile.

Now, to me fractions of a second don't mean much in the real world. Or maybe I should say the world of stop light racing. Granted those numbers are for stock cars and I was probably racing a stock Camaro, but I still had him by several car lengths and if we were on a twisty road... bye bye. In all I would say that a 540 beats a Camaro in all categories and making the 540 even faster makes it all the sweeter. :thumbup:


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## JetBlack330i (Feb 8, 2002)

Aye Chingow! said:


> Your comment about not beating a Camaro got me thinking. Only because I have beat Camaros (and even owned a Z28 once). So I went hunting around the web for 0-60 and 1/4 mile times of the e39 540 and a Camaro Z28 SS and the numbers pretty much hover around 5.5 sec 0-60 and 14 sec 1/4 mile for the 540 and 5.2 sec 0-60 and 13.6 sec 1/4 mile.
> 
> Now, to me fractions of a second don't mean much in the real world. Or maybe I should say the world of stop light racing. Granted those numbers are for stock cars and I was probably racing a stock Camaro, but I still had him by several car lengths and if we were on a twisty road... bye bye. In all I would say that a 540 beats a Camaro in all categories and making the 540 even faster makes it all the sweeter. :thumbup:


Look at the list of thing that was being proposed. You do that list to a 540, and for the same $ I can buy 3 Camaros. Or, if you're talking about racing, for half of your budget I can supercharge a Camaro and all you'll see is my dust.
The point is... if you buy a BMW, don't try to turn it into a racer. Enjoy the balance of luxury, utility and (reasonable) performance. If you want a racer, go buy one (why do you need 4 doors in a racer?).


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## Aye Chingow! (Oct 6, 2003)

JetBlack330i said:


> Look at the list of thing that was being proposed. You do that list to a 540, and for the same $ I can buy 3 Camaros. Or, if you're talking about racing, for half of your budget I can supercharge a Camaro and all you'll see is my dust.
> The point is... if you buy a BMW, don't try to turn it into a racer. Enjoy the balance of luxury, utility and (reasonable) performance. If you want a racer, go buy one (why do you need 4 doors in a racer?).


I see your point. But  I would still rather have a really fast BMW for around $35K (pre-owned 540 with lots of goodies on it) than a really fast Z28 for ??? (not sure what they go for now). And I do agree that in a straight line the Supercharged Z28 would be an animal. But is it any faster than a supercharged 540? :dunno: AND  we don't see many Camaros on the GT circuit (races with corners ), but there are tons of 3 series bimmers.

Anyway, I understand what you're saying. Its just that you got me thinking and I was curious about the performance specs of the Z28 since I got ride of mine some time ago and I don't remember it being quite as fun as my current car, nor as chic :thumbup:

Forgot to add that I need a racer with 4 doors so i can haul the family around and use it for business. Doesn't look too good when you ask a client to climb into the back seat of a Camaro...  Of course I'm not going to be putting CF fenders or hood on it either.


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## DanB (Feb 20, 2002)

JetBlack330i said:


> Look at the list of thing that was being proposed. You do that list to a 540, and for the same $ I can buy 3 Camaros. Or, if you're talking about racing, for half of your budget I can supercharge a Camaro and all you'll see is my dust.
> The point is... if you buy a BMW, don't try to turn it into a racer. Enjoy the balance of luxury, utility and (reasonable) performance. If you want a racer, go buy one (why do you need 4 doors in a racer?).


Why didn't you buy a 323i? Isn't buying a 330i essentially paying 7K more for .7L and a few more standard options?

Does the M3 CSL fall under the same category? It's basically an M3 with many of the mods talked about in this thread done from the factory. What's the difference between the factory doing it and us doing it if the quality meets or exceeds that of BMW?

-DanB


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## JetBlack330i (Feb 8, 2002)

DanB said:


> Why didn't you buy a 323i? Isn't buying a 330i essentially paying 7K more for .7L and a few more standard options?
> 
> Does the M3 CSL fall under the same category? It's basically an M3 with many of the mods talked about in this thread done from the factory. What's the difference between the factory doing it and us doing it if the quality meets or exceeds that of BMW?
> 
> -DanB


A CSL beats the hell out of a Camaro.
Still, I wouldn't buy one. Not for the price they are asking.


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