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Best ways to add Horse Power to 2003 M5

28K views 69 replies 32 participants last post by  crds 
#1 ·
Hi everyone, I'm looking to purchase a 2003 m5 before the fall but i want to give it some more power. So I would like to know what you think is the best way to get the m5 to around 450-500 horse power. Ive been doing some research on aftermarket parts and so far a performance chip and a new air intake would be a good place to start but i would like to know your opinions on this.
 
#2 ·
Have you driven the M5 for extended periods of time, is the 400 hp not enough?

Its a naturally aspirated engine so anything you can think of can be done to the engine.
 
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#3 ·
Oh no dont get me wrong I would be perfectly happy with this car bone stock its that good. I have been in several rides before in both the e39 and e60 and the extra power in the e60 was just unbelievable. i prefer the e39 though and would love to just give it a slight power increase.
 
#6 · (Edited)
If you are looking for reliable HP, $5000 should get you 40-60 real Hp,
 
#7 ·
I would concentrate your efforts on finding a great example of an M5 rather then worrying about what to mod the car with. Remember the more power you make from your engine the less life you will have in it, and the more parts need to be replaced. If you really want 500hp why not save the $5000 in mods and spend that $5000 to buy an E60, then you are done.
 
#8 ·
Headers for between $2-3K are worth 25-30HP. The other option is ESS which is about $9K and gives you 150HP. There's not a lot in between.

We don't have a ~$500 JB3 that we can pop in for 50-70HP, if that's what you were looking for.
 
#10 ·
Ive been doing some research on aftermarket parts and so far a performance chip and a new air intake would be a good place to start but i would like to know your opinions on this.
Any real research will indicate that an intake and chip is a very poor modification for our cars, as the stock intake is an exemplary system.

The biggest gains to be had are headers for the money you are talking. A supercharger is really the only way to go if you want a significant power increase.

Coming from a 528 I highly doubt you will need, at least initially, extra power. I too have driven in an E60 M5 as well as much faster cars yet I do not desire to make my car any faster, as balance is key. Buy the car and then if you want to make the modifications, some research here will give you all the answers you are looking for.
 
#15 ·
Any real research will indicate that an intake and chip is a very poor modification for our cars, as the stock intake is an exemplary system.
Please search the threads. He's some product topics to help you on your way.

Supersprint Headers
Evolve Headers
Dinan Headers
Evolve Alpha N
Powerchip

Adding to previous comments, there's no point throwing money into performance parts if the car itself is in bad condition. You might find that you'll spend a percentage of your projected $5000 on renewing OEM parts (eg. MAFS, CPS, air filters, thermostat, clutch etc)
There are only 2 relatively cost effective ways.

1. Supercharger (ESS $8k or $10k or Dinan $30k)
2. Headers + software (Dinan $8k, Supersprint $2500, Evolve $2500, plus $5-700 for software)

My advice, don't bother modding. Save your money for the insanely expensive repairs.
I got a 4" binder's worth of previous maintenance done to my car including some serious cash repairs like a driveshaft, VANOS solenoids, etc, and I still put $3k into it with in the first month of ownership.
Well said, gentlemen. I think you catch the drift, OP. Save your money. Maintenance is inevitable.
 
#11 ·
Please search the threads. He's some product topics to help you on your way.

Supersprint Headers
Evolve Headers
Dinan Headers
Evolve Alpha N
Powerchip

Adding to previous comments, there's no point throwing money into performance parts if the car itself is in bad condition. You might find that you'll spend a percentage of your projected $5000 on renewing OEM parts (eg. MAFS, CPS, air filters, thermostat, clutch etc)

Good luck.
 
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#30 ·
I have an essentially stock M5 (I have Magnaflow Cat-back's but that's not really significant). In my first track experience with the M5 last fall, horsepower wasn't an issue - so much not that we ran the air conditioner full-tilt because it was 85+ out and 90+ in the car. I was still able to run up from 95 mph up to over 120 mph in about 6 seconds on the first half of an 1800 foot back straightaway, at which time I had to back off the throttle because in another 5 or so seconds I'd be needing to make a right-hander at about 100 mph. Those 1800 feet went by real fast. All a few more horsepower would do is take me to a higher speed, which means an even more aggressive slow-down and ultimately greater skill needed to negotiate the course. I was plenty happy with having 400hp and certainly was running right there with the M3's, TT's, and Z06's on the track. I didn't feel slow at all!

Relax and enjoy, and put the $5K toward increasing your driving skills!

-crds
 
#13 ·
There are only 2 relatively cost effective ways.

1. Supercharger (ESS $8k or $10k or Dinan $30k)
2. Headers + software (Dinan $8k, Supersprint $2500, Evolve $2500, plus $5-700 for software)

The ESS supercharger kit will get you up to either 525 or 550 bhp with no other mods. The Dinan kit will get you closer to 620 bhp but it requires a lot of other modifications (including the $8,000 headers) to get you to that power level.

The Headers will net you about 30-40 reliable bhp and about the same torque. Do some research.

My advice, don't bother modding. Save your money for the insanely expensive repairs. And good luck with the search for the car!
 
#14 ·
I got a 4" binder's worth of previous maintenance done to my car including some serious cash repairs like a driveshaft, VANOS solenoids, etc, and I still put $3k into it with in the first month of ownership. I budgeted for it so it wasn't a big deal, but if you're not prepared for it things can add up quickly.
 
#18 ·
I think 5k is better spent on a driving school and lots of track time+maintenance to nurture the existing 400 ponies. That way, you learn how to best utilize the 400hp you already have and this can easily beat someone with no driving skill with 500hp.
 
#20 · (Edited)
Lots of great advice in this thread. Power is addictive, and so I can understand your deisre for more of it, but my personal opinion is that if you have the budget for a 2003 M5 + $5000, I would concentrate on finding a really top notch car to buy in the first place, make sure it is maintained well, and then get some track time & tuition.


For a big car, a completely stock M5 can really hustle. The best place by far to find this out is on a track, and if you happen to have little prior advanced or race tuition, you will be staggered just how much better you can be with some training from a good tutor. Not trying to belittle your driving ability at all; you might be a seasoned racer, but usually the weakest link in a performance car is the chap behind the wheel:wroom:. You could have some major fun with $5k for track time and maintenance.


If you must have the power, headers really are the best starting place, unless you find a bit more cash and fancy going supercharged. Good luck with your search.
 
#21 ·
Lots of great advice in this thread. Power is addictive, and so I can understand your deisre for more of it, but my personal opinion is that if you have the budget for a 2003 M5 + $5000, I would concentrate on finding a really top notch car to buy in the first place, make sure it is maintained well, and then get some track time & tuition.


For a big car, a completely stock M5 can really hustle. The best place by far to find this out is on a track, and if you happen to have little prior advanced or race tuition, you will be staggered just how much better you can be with some training from a good tutor. Not trying to belittle your driving ability at all; you might be a seasoned racer, but usually the weakest link in a performance car is the chap behind the wheel:wroom:. You could have some major fun with $5k for track time and maintenance.


If you must have the power, headers really are the best starting place, unless you find a bit more cash and fancy going supercharged. Good luck with your search.
Very well put :M5launch:
 
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#24 ·
Great; the aim of most on the board is to help people get the most they can out of the M5 experience. If you do decide to go after more power, there is certainly a vast knowlege base of modified cars on here. Be sure to post some photos when you buy a car!
 
#23 ·
Let's also mention that more power equals the need for more stopping power and a BBK will cost you a few K's.

There are also Dr. Van Manen headers. Search it.

copy and paste this into google:

site:m5board.com Van Manen headers

Cheers.
 
#25 ·
Let's also mention that more power equals the need for more stopping power and a BBK will cost you a few K's.

TCheers.
Why do people always say this? Unless one is tracking the car and overheating the brakes...why does one need "bigger brakes" just because they have "more power? I have had my ESS kit for almost two years now...stock brakes do just fine......

IMHO...unless one is tracking the car...BBKs are an unnecessary expense.....but that is just me, LOL:cheers:
 
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#27 ·
BBK is like insurance, you never know when you need them. But there might happen something, when you wish your car has BBK. imho
But for 3-6k I disagree. Your BBK will not stop your car much faster than my stock brakes.....just saying....hmmm
 
#29 ·
take a driving course. best mod you can do is mod the driver...
 
#32 · (Edited)
A big brake kit, correctly matched to the ABS system will outperform the stock brakes, but they will not stop the car in any less distance on a single stop. I can easily get the ABS to cut in at any speed with the stock brakes and this represents the greatest amount of deceleration that can be acomplished irrespective of brake system; maximum deceleration in our cars is governed by grip, not braking power. If you are likely to be performing several hard stops from high speed (like on a fast track for example) you may get brake fade from the stock brakes, and this is when you need the bbk.

For road use, the stock M5 brakes are plenty.
 
#35 ·
The misconception with these cars now is that just because the price of entry has reduced does not mean that the maintenance costs have. Get used to the M5's performance and vehicle dynamics before comitting to the modifications that you want to do.

Without doing the maintenance on the car, any mods is basically moot because if you ignore one repair or preventative maintenance action then it will have a domino effect and pretty soon that $1000 bill turns into a $4000 nightmare. It isn't to be neurotic but if anything needs attention, take care of it then and when the money is in place for the modifications that you want to do then do them. The most popular modifications are exhaust, suspension, intakes, brakes, wheels and software. A lot of people forget but a lightweight set of wheels can give the feeling of added horsepower because of the reduction in rotational mass. Just a little food for thought. Good luck with your purchase and don't settle just because it has a "low price." That will come around to bite you in the *** when it comes time to have any work done on it.
 
#36 ·
Another question I have now is about the maintenance. All the post about saving money for maintenance, can you give me an idea of what are some normal things that will go wrong that will dip into my 5k. I just want to have an idea of what to expect and what to look for in the one I buy.
 
#43 ·
No one has mentioned going with a different differential, like the Dinan. Any thoughts?
 
#44 ·
No one has mentioned going with a different differential, like the Dinan. Any thoughts?
Seems to be completely personal preference.
Will add torque multiplication so make it "feel" faster to some...."Poor Man's Supercharger" it has been called
The debate went round and round for a long time in here about whether it had any impact on acceleration....consensus seems to be "no"

You will run slightly higher RPMs throughout the speed range..slightly less MPG

Several members have converted and then gone back to stock..others LOVE it.

Best advice is to find a member who has done the conversion and see if you like it...

Good luck,
Bri
 
#46 ·
very interesting.

thanks for sharing that link.
 
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