Building a Dinan 540iA

Stock Specs

  • Engine 4.4 Liter V8
  • Horsepower 282
  • Torque 334 @ 3500 RPM
  • 5sp Automatic Transmission
  • Top Speed 128 Electronically limited
  • Differential non-sport 2.81

Quick Links

Dinan Suspenison

Dinan Engine Software

Dinan High Flow Throttle Body

Dinan Cold Air Intake System

Dinan Transmission Software

Dinan Free Flow Exhaust

Dinan 3.15 Open Differential

Dinan High Flow Intake Manifold

Dinan High Flow Air Flow Meter

Walker/Dynamax Resonator


Underdrive Power Pulleys

FSD+ProKit Suspension

Eibach Sway Bars

Modified Specs

  • Horsepower 340 Torque 363
  • Top Speed (160+)
  • Dinan Stage V Engine Software
  • Dinan Transmission Software
  • Dinan High Flow Cold Air Intake System
  • Dinan 3.15 Differential
  • Dinan Stage I Suspension
  • Dinan High Flow Throttle Body
  • Dinan High Flow Air Flow Meter
  • Dinan Front Strut Brace
  • Dinan High Flow Intake Manifold
  • Dinan Free Flow Exhaust
  • Hella Celis Smoked Tail Lights
  • Hamann HM2 19"  Pic
  • Pirelli PZero Rosso 275/30/19 R 245/35/19 F
  • Resonator Removal Pic
  • M5 Subwoofers
  • M-Sport Steering wheel Pic
  • M5 Fender Liners
  • Fender Rolling Apparatus Pic
  • SSR GT3 Satin wheels  Pic
  • FSD+ProKit Suspenion New
  • Eibach Sway Bars Front and Rear

Summary of Dinan Modified Specs

  • The information below are notes from my Dinan modifications.  You mileage may very, but should be reasonably close. Modifications to your car is done at  your own risk and expense.  There have been redesigns to some of the modifications Dinan produces.  Given that, I will not change my conclusion section, as it may apply to others.  I will, however,  post updates regarding these changes!

(The most current information is at the bottom of this page.  Read the SUMMARY to bypass all the verbage.)

  • Dinan Engine Performance Software: This is the starting point.  You might notice a slight increase in power with Stage 1, but the big difference is the governor that restricts your top end engine speed will be gone!
  • Dinan Cold Air Intake System:  This is a very nice upgrade to your car.  It gives you a noticeable performance increase in all RPM ranges especially above 3500 rpm not to mention a nice growl when you step on the gas.   The car can breathe now and get the air it needs to get the additional 13-20 HP in conjunction with Dinan's stage 2  engine software.   You can hear the difference with the video in the Media section.  This is one of the best designed and cleanest systems on the market.  It extends from you airflow meter down past the headlight and near the opening of the front spoiler vents.
  • Dinan Performance Transmission Software: It only took a few seconds to realize the difference.  The shift seemed incredibly quick!  I came to a stop light and  waited for the green.  I got the green and gave her about 3/4 pedal!  I was thrusted into second gear from 1st!   Dinan claims about a 25 percent increase in shift pressure when you're getting on the gas.  I would agree to that being very close if not under rated.   If you have an automatic do yourself a favor and get this upgrade.
  • Dinan Free Flow Exhaust:  There is a lot to choose from..  It comes down to a few things.  What sound are you looking for and how is the quality and how are the looks?  I'm very happy with the sound from the Dinan exhaust.   When you step on the gas they ROAR.  The fitment could be much  better for the e39.  They do hang down and stick out  to far.   Once again check out the media section to get a idea of the sound and look. If I were to puchase another exhaust it  would be Remus they sound fantastic and offer a little more back pressure.  Supersrpint sounds good too and is probably the best looking.
  • Dinan 3.15 Open Differential:  My car came with a 2.81 differential. After the installation of the new differential my car is much quicker off the line and feels much faster overall.  This modification is worth every penny.  Listed below are the 0-60 times with the 2.81 and 3.15 differential. If you can swing the extra dollars for a limited slip differential doit!  Dinan's prices are high and there are other options.  You can save several dollars and go here to get yourself some new gears KOALAMOTORSPORTSWhen I was shopping for the gears there wasn't many options or flavors.  I would get a 3.64 lsd differential now if I were shopping:)

Dinan CAI, Engine software, Transmission software and exhaust with 2.81 and 3.15 differentials.

0-60 mph with 2.81 differential = 5.8

0-60 mph with 3.15 differential = 5.2

A couple things I noticed with the 3.15 differential installation.  Give or take 100 rpm's.

  1. Rpm's at 80 mph in (Drive) with a 2.81 differential is 2300 rpm's and a 3.15 is  2700 rpm's.
  2. Shift point from 3rd gear to 4th with the 2.81 differential is 110 mph and with the  3.15 differential is 100 mph. This is manual shifting at about 6500 rpm.


  • Dinan Stage I Suspension: I had the non-sport suspension.  My car was very high and the suspension was very soft.  I opted for the Dinan stage I suspension.  It's a little pricey, but worth it  and it made a considerable difference.  My car has a more aggressive stance and looks more sporty.  I was worried that I would lose the luxury ride my car, but the difference is just a little stiffer ride. The car is a lot lower and handles much better.  The Koni shocks and struts are adjustable and are set for the softest ride at the moment.  I have added a comparison picture just click this link and check out the difference for yourself.
  • Dinan High Flow Throttle Body:  This is the only modification I cant really tell a big difference with.  Nothing to really brag about.  It is necessary to have this installed if your going to install the high flow air flow meter.
  • Dinan High Flow Air Flow Meter:  This mod requires Stage IV engine software.  The car seems much faster now, but not nearly as quick.   I lost low end but, gained topend doh.
  • Dinan High Flow Intake Manifold: The manifold and Stage V engine software were installed today May 1, 2002.  I can tell you that so far it feels slower at the take offs, but once I hit about 4500 rpm's the car takes off.  See the Manifold video.


  • Update: I haven't come close to 5.2 0 to 60 mph since the High Flow Air Flow meter.   The best I can get is 5.7-5.8 and that is consistent in 60 degree weather.  The car loads up in 1st gear and hesitates before shifting to 2nd gear.  Very similar to the OEM shifting.  The great shift pressure is gone in this range. Unfortunately, this is the range where you would feel it the most and get the best results.   I have spoken with Eric Forester of Dinan Engineering about this issue.  It is believed to be a software issue and the Software Engineers of Dinan are working on  it.  I have not heard anything else since April 19, 2002.


  • Update:  Wednesday evening May 1, 2002 - The installation of the intake manifold did not correct the issue with the transmission software.  It is as if the transmission software is not even installed.  The car loads up even more now in the 1st gear before shifting to 2nd.  I'm not a mechanic, but believe there are issues within Dinan Stage IV and V software, or perhaps the mass air flow sensor.  I would like to see Dinan make corrections to the Stage V engine software so it is better suited with the Manifold and High flow air flow meter.  I Just got back from a cruise on the freeway.  I found a nice section with nobody near me and let her rip.   Going up hill the car accelerated to high speeds in a very short time.  The top end  just keeps on accelerating faster and faster from about 45 mph up.  The low end side is TERRIBLE from 0-20mph.   The car does not even want to power brake burn offs.  The time lost in the quarter mile and 0-60 runs are brutal.


  • Conclusion:  My HP  and Torque from Decembers Dynojet run was 312 HP at 5700 rpm's and 332 Torque at 4500 rpm's.  This was before the Throttle body, High Flow Air Flow Meter and Intake Manifold installations.  In conjunction with the 3.15 Differential installation my 0-60 mph times were 5.2 - 5.3 seconds pretty much constant with decent launch's.  After the installation of the  Throttle body I noticed no significant changes in performance.   After the High Flow Air Flow Meter installation I could tell I dropped power on the lowend. The best 0-60 times were 5.7 seconds and very consistent.  My 1/4 mile times were 13.9-14.1. The Dinan Transmission software was not working like it was before the install.  It lost its punch from 1st to 2nd gear.  This is where it really made a difference.  After the Intake Manifold installation,  I could tell right away my car lost more of the lower end side.   I had my car dynoed again at the same place and same dyno as the December run with just about the same temperature etc.  Here are the numbers 325 HP at 5900 rpms and 364 Torque at 4400 rpms.  I should of had 320 HP with just the Throttle body installation.  I picked up only 13 HP, but 32lbs more torque with 3 modifications.  I was happy with the torque readings and who wouldn't be.  That's the 2002 M5 territory.  The 13 HP was not adequate especially with the engine management software (Dinan Stage V Engine Software). I gained numbers and lost considerable quickness through the 1/4 mile. The amount of power lost on quickness at the lower end is far to great.   At this point of my modifications I'm disappointed in the lower end.   My advise to anyone who is installing mods from Dinan to stop at the throttle body and stage III engine software.  My car was very quick at this stage of modifications. The car was quick and fast!  I'm thinking about  having  my old manifold reinstalled and possibly my air flow meter since the Transmission software does not work well with the new air flow meter.  If Dinan got the Stage IV engine software  working  with the air meter or vice versa  the car would be a beast.   Stage V software is supposed to be a match for the intake manifold.  This may hold true on some cars, but not mine.  It should be reconfigured and setup for the manifold only. This could possibly bring out the HP needed for this installation. There is probably another 15 or more HP trying to get out.  One last comment! The car does move out from 20-30 mph up to the redline and seems to be much faster, but from 0-20 the car lost quickness.  If you want quick 1/4 mile times or 0-60 times stop at  the throttle body unless your  going to install the supercharger.


  • Update:  May 30, 2002 - Spoke with Dinan Engineering.  They have released a new High flow air flow meter that should correct the issues with  low end speeds. Mine is on the way to the dealer.  I will update the differences once it is installed.


  • Update:  June 10, 2002 - I took my car to the dealer for a 4 wheel alignment that I was overdue for when I changed out the suspension. I also had a radiator hose that started to leak replaced no charge and an the secondary air pumpr replaced no charge that sounded like a turbine when the car was started cold.  The mapping thermostat was also replaced no charge.  Whatever that is?  I also had my Koni shocks in the back stiffened up a bit to eliminate tire rubbing when hitting dips on the freeway at high speeds.  The car is a little stiffer for sure, but handles great with the Dinan suspension and the new wheels and tires!


  • Update:  June 11, 2002 - My replacement High Flow Air Flow Meter was installed.  This was a redesigned air flow meter that is a little smaller in diameter then the original.  This redesign was to fix the issue with the loss of low end speeds and the impact it had on the transmission software for the automatic transmissions.  I have only driven the car a few miles, but I can tell that the transmission software is working again but, its not quite there yet..  I have good shift pressure from 1st to 2nd gear.  The takeoffs are much better than before the swap, but not as quick as it was before the high flow meter and manifold installations.


  • Update:  June 11, 2002 8:30 PM  -  I tested the new high flow air flow meter thoroughly.  The power is back and the shift pressure is better but, still not as quick as Stage II.  The Stage V Engine software, MAF and Manifold are working together now and not against each other.  The car feels quicker and fast!   The correction in the air flow meter made a significant difference.  I'm taking a little loss in take offs but making up for it in top end speeds.  The transmission software is working much better then with the first air flow meter, but not as good as the oem air flow meter.  Shifts are still a little less pronounced then at stage II but, better then stock.  Overall,  I'm happy with the changes made in the redesigned  high flow air flow meter, but feel there could be some fine tuning for the engine software and the transmission software to take full advantage of the increased air flow!  Just a little to conservative in my opinion


  • Update: June 24, 2002 - I had the OEM resonator removed. The only thing it's good for is air flow restriction and noise reduction, not to mention giving you a little back pressure for low end launching.  A straight through exhaust is loud and needs a small sub muffler or resonator to keep the exhaust quiet.  A resonator is usually a small, perforated core glass pack placed somewhere in-between the catalytic converter and the main muffler. My car was very loud without a Resonator so, I had 3 inch Walker/Dynamax Racing Resonator installed. I believe the Part number is 24222 .  The flow is straight and less restrictive with just enough back pressure. Not to mention about 10-20 lb. less in weight. Sorry, I don't have a pic of the new resonator. The car has a deeper sound now and more throaty. Check out the Video above in the Multimedia section. The burnout video is also with the new resonator. Here is a pic of the OEM Resonator .  That's Kevin of ED Hanson's Muffler Service (619) 698-7030 Sping Valley, CA.  These guys are great and the prices are the best.  If your in Southern Cali and need exhaust or custom pipes go to ED's.


  • Update: November 4th, 2002 - Was time to replace the back tires. I purchased Bridgestone S03's.  I've heard conflicting information about them.  So far I like them!  They handle great and the ride is excellent, but the Pzero Rosso's handle better in dry conditions.


  • Update:  November 18, 2002 - I contacted Dinan regarding the high flow air flow meter and automatic transmission software. I spoke with Chris of Dinan Engineering who was very knowledgeable and  informative.  I explained to Chris that I did an experiment with my OEM MAF VS. my Dinan MAF.  I told him that the transmission shifts harder and quicker with my OEM MAF and 0-60 speeds are faster with the OEM MAF.  Chris asked what the purchase date of the redesigned MAF was and what version of transmission software I had installed.  Unknown to me there are 3 versions of the Transmission software.  One version for stage 1-3 and another for stage 4-5 and one more for the supercharger.  Apparently, I have been running the first stage designed for Stage 1-3 doh!  I took the car to Cunningham BMW and they immediately took my car in and uploaded the correct version of transmission software.  I didn't have to wait at all!  The performance of the car is improved.  I will do some more testing tonight in less traffic.  Here are a few pics of the software  installation process.         PIC1   PIC2   PIC3  I didn't think this was going to make to much if any difference at all but, I just got back from testing the car and I get zero hesitation NONE.   I was getting some hesitation at high speeds, as well as launches. I floor it and it chirps the tires and goes.  The version of my software is 4.06 for Stage 4-5.   See pics in above update!


  • Update: April 14, 2004 - Changed out the Hamann HM2 wheels for a smaller lighter wheel.  I had been going through tires like butter with the 275/30/19 Pzero's and S03's.  This alone warranted the change.  It was a tough decision, but I decided on SSR GT3 18" wheels PICThese wheels weigh in at 23.8 lbs for the front 18"x8.5" and 25.2 lbs for the rear 18"x9.5".  The tires I chose were Michelin sport A/S 275/35/18 rear and 245/40/18 front.  The reason I chose A/S was I wanted more tread life a quiet ride and a comfortable ride without giving up to much performance. .


  • Update:  January 4, 2005 - Installed Evosport underdrive power pulleys.  I don't have any real world numbers yet but, should be getting the car dynoed soon.  The engine feels very tight.  The throttle response is immediate.  The car definetely, feels quicker and faster.  Seems like the car gets to high rpms much quicker.  I like it.  Here is a pic of the pulleys PIC.


  • Update:  January 16, 2005 - After the EvoSport underdrive pulley upgrade and after replacing my dirt saturated filter on my Dinan CAI, my car has been running like its on steroids and on that note here is my story..  My buddy who has a beautiful 2004 Mercedes e500 with a few minor modifications purchased a Beltronics Vector fx 2 performance timer.  It's supposed to be accurate within 50-100 milliseconds.  His times with his e500 stock were 0-60 mph in 6.1.  After he changed out the exhaust, modified the intake and  changed to ltw wheels his best time has been 4.90 0-60 mph and 13.45 quarter mile with a full tank of gas and an xtra 250 lbs in his car.  Decent bragging rights for a 3800 LB sedan.  I borrowed his Beltronics device and attempted some times on my car.  I had a lot of trouble trying to launch without burning the tires and the rearend kicking out to the left. Best time I could muster was 0-60 mph in 5.20 and 13.70 quarter mile.  On this particular run I had a bad launch with the DSC on and chuged out slowly..  I  let up just before I reached the quarter mile and still got 13.70 flat.  Today was a better day:) I reduced the air pressure in my rear tires from 35 to 30 psi.  Here is the run down.  Half tank of 91 octane.  Temperature about 64 degrees F.  Flat road and nobody around.  First two attempts I got to much rubber and stopped.  The 3rd attempt was near perfect.. I manually shifted from 2nd-3rd and let the car shift it self into 4th.  My time was 13.15 with a trap speed of 107.1 mph.  0-60 mph was 4.80.  Here are some pics of the run. Pic1  Pic2  Pic3  Pic4  On a final note.  I realize this time is very fast and it even leaves me shaking my head.  I know my car is quick but, I feel a time of 5.1-5.2 0-60 mph and a 13.5-13.7 quarter would be more accurate.  Regardless, my friend has a new goal to shoot for.


  • Update:  July18, 2005 - I changed out my MAF (mass air flow sensor) in a test to find out if my existing sensor was not running up to par.  My car has 85k in miles and is running strong, but has been surging at idle for quite some time.  After replacing the MAF and running the car for roughly 3 cycles and 50-60 miles, the idle is smooth and the power has actually increased.  I didn't notice much of a difference in first gear, but from 2nd gear up the car is pulling harder no doubt about it.   I will clean my original MAF and shelf it for a rainy day.


  • Update:  July 21, 2005 - I currently have over 21k in miles on my Michelin A/S tires and they're finally starting to show the wear bars on the rear tires.  These tires don't  handle like the Pzero or S03's, but  they hold up a hell of a lot better.   IMO the loss of a little cornering is worth the money saved in the long run.  I take back every nasty remark I've made about the Michelin A/S.


  • Update: December 15, 2006 - My Dinan suspension was getting soft due to the 80k miles of use and I needed to correct it.  I did not want to spend a rediculous amount of money and purchase replacement  springs from Dinan.   I decided to replace the entire setup with the Koni FSD and the Eibach prokit springs. I purchased the kit at ask for Jason Burkett.   I have over 500 miles on them now and I really like the combination of handling, performance and comfortability.  Riding and handling characterstics are very similar to Dinans setup with the difference being a more comfortable ride with the FSD's. The FSD's absorb dips and bumps effortlessly and the Dinan setup is somewhat more harsh and less evolved.  Here is a comparison pic of the car with the new FSD and the Dinan suspension click hereHere are the measurements of the drop click here .  Here is Dinans measurements after 90k miles on them click here .

    Peformance is very close to the same or near equal, I will try to explain this the best I can. Aggressive cornering is not a problem with either setup. FSD's feel like your glued to the road, but riding on a carpet. Dinan's setup feels like your glued to the road without the carpet. It's a strange/weird feeling to have the comfort that the FSD's bring and maintain performance. Hopefully, they will last 80k miles:)

    I have to give the FSD's a +1 over Dinans older setup. The advanced technology of the FSD's wins. For pics of the car with the FSD+ProKit suspension installed click


    Update:  January 13, 2007 -Finally got my Eibach sway bars installed. A friend of mine, that many of the Southern Cali peeps know (Shane) installed them in record time of 2 hours using a lift. Oka little under two hours to be fair. He started at 10:30 AM and was washing up at 12:30 PM. Is that crazy or what.

    The price for the install at a dealer is 800.00 or more based on their FRU's (flat rate units). That's what Cunningham BMW was going to charge and quoted 6-7 hours to complete. Other price quotes were in the 600.00 range. Shane is a BMW Master Tech and is fair with his pricing, which was less than both prices quoted.  Shane also looks for any other issues that may be present and will alert you if he sees something that may need attention. 

    The change in handling is very noticeable when taking corners. The body roll has been significantly decreased. The car dives into the corners while you remain planted in the driver seat.  The stability and increased performance during spirited driving is phenomenal. I only wish I had done this modification earlier.  I can't say enough about this modification and would highly recommend it if your car has sport or non-sport sway bars or even M5 sways.  One word of advice is to be aware that even though the car is handling better and taking corners considerably flatter it will be easier to oversteer and kick the rear end out.  Ask me how I know.

    The car may be a 4-door sedan, but it has taken on a new personality and I love it. With the new eibach sway bars and FSD suspension+prokit springs the ride is better then ever. This upgrade along with the suspension and differential were the best bang for the buck modifications to date, with the exception of the transmission software. My car has 103k miles, but feels like a new car.

    Formula 5 pre-lube was used on the bushings to prevent squeaks. I'll report my findings a few months. Beastmaster Brackets were used on the rear sway bar, as the OEM brackets will break more often then not.  My control arms were replaced a short time ago and is recommended if your installing the sways. The increased stress on the old control arms and bushings will undoubtedly finish them off.

    Thanks Shane great job as usual!  Pics coming soon  


  • Update:  October 27, 2007 - The alternator went out at 110k miles not bad.  The bad is its a water cooled alternator and costs anywhere from $550.00 to over$ 700.00 depending on where its purchased.  Installation is about an hour by a master Tech.  Also, buy some  coolant as your going to lose it when you pull the alternator


  • Summary: After a few issues were resolved such as,  the MAF and the correct software being installed for the transmission to sync with the engine modifications the car runs very strong. I'm very pleased with all of the above modifications.  Because of the incorrect software being installed early on, I'm certain I would have had a different response regarding the Throttle body and MAF installations noted above. There are two things I would change.  I would probably chose a Remus exhaust over the Dinan for a deep tone a less raspy sound and better fitment.  The 2nd thing would be change the Differential to a 3.64 LSD for the automatic or better yet scratch the 3.64 and for another 3k you can get an Ess supercharger for your 540.


 I hope this information has helped you and you have enjoyed your visit! Cya on the streets!!