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Discussion Starter #1 (Edited)
Just got my car back and did a baseline dyno.

I have been searching for an hour and haven't found anyone else with a baseline dyno posted.

Anyway the car is completely stock besides -
Vellano VSH 20in chrome wheels (any power loss????)
Charcoal Filters Removed

The baseline dyno came back with 392.8 max HP.

I was told there is 25% power loss in the drive line etc...

Giving a crank HP of ~520HP... Does that seem right?

The Dinan S2 suspension and exhaust were then installed. I love the exhaust and the suspension, but I only have two issues.

1. Since the suspension was installed I now have a clicking noise that is coming from the rear of the car. It is the loudest when EDC is turned off and I have to be going over a bump... a speed bump at low speeds produces the noise the best. I was told by the installer to drive the car a little and make sure everything seats correctly. The radio and AC must be off to hear it as well. It is very annoying... anyone else have this issue? The installer toke 3 hours to completely go over the installation and couldn't find anything, but he did agree the noise is not normal. Dinan said it maybe the progressive springs in the back and they have only heard of one other case of this happening.

2. I love the look of the exhaust tips and the sound is perfect, but the Dinan mufflers are just plain ugly.... The tips are nice and polished but the mufflers look like someone made them in their garage.

Would it be possible to chrome or paint the mufflers to give a uniform look??

See the attached pictures for a comparison..
 

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Congratulations on your mods. 393 rwhp seems a bit low. What gear did they use for the final numbers? The proper gear is the one which uses a 1:1 ratio, which in the M5 is 6th gear I believe. If your dyno runs were done in 4th or 5th you will not be showing the max rwhp put down by your car.

Some people have had problems getting up to 6th gear due to hitting the limiter in 5th gear while on the dyno.

Also, if the shop told you 25% drivetrain loss they are smoking crack. The DT is more efficient than that and should be around 17%-18%. Automatic transmissions aren't even typically 25%, much less AWD (which are usually the least efficient).

I would get another dyno pull from a second shop just to see what they come up with. My first reaction was they must have a mustang dyno since these types of dynamometers typically report 20 hp less.


Regards,

Darren
 

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Congratulations on your mods. 393 rwhp seems a bit low. What gear did they use for the final numbers? The proper gear is the one which uses a 1:1 ratio, which in the M5 is 6th gear I believe. If your dyno runs were done in 4th or 5th you will not be showing the max rwhp put down by your car.

Some people have had problems getting up to 6th gear due to hitting the limiter in 5th gear while on the dyno.

Also, if the shop told you 25% drivetrain loss they are smoking crack. The DT is more efficient than that and should be around 17%-18%. Automatic transmissions aren't even typically 25%, much less AWD (which are usually the least efficient).

I would get another dyno pull from a second shop just to see what they come up with. My first reaction was they must have a mustang dyno since these types of dynamometers typically report 20 hp less.


Regards,

Darren
Agree with everything, but you'll probably hit the speed limiter in 6th before you hit the HP peak at 7750 rpm. No way this drivetrain loses 20% - it was specifically designed for minimal rotating mass and losses. Probably 17-18% is right. 392 would then give you only 478 HP which is way low. Most good dyno runs show 420-430 rwhp on the M5 with the CF's removed.

It's possibly your 20" chrome wheels are having a significant effect - but certainly not enough to account for 40-50 HP. Do you know how much they weigh? If they're over 35 lbs, you might see a few HP difference.
 

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Agree with everything, but you'll probably hit the speed limiter in 6th before you hit the HP peak at 7750 rpm. No way this drivetrain loses 20% - it was specifically designed for minimal rotating mass and losses. Probably 17-18% is right. 392 would then give you only 478 HP which is way low. Most good dyno runs show 420-430 rwhp on the M5 with the CF's removed.

It's possibly your 20" chrome wheels are having a significant effect - but certainly not enough to account for 40-50 HP. Do you know how much they weigh? If they're over 35 lbs, you might see a few HP difference.
The run was on a Dyno Dynamics dyno. I have read that, like a Mustang dyno, they typically show 10% less rwhp than a Dynojet dyno. So it looks like roughly 435 rwhp adjusted to a Dynojet reading, but that is just my guess.

As far as the gearing, I had the same problem with my E55. My 1:1 gear is 4th, but the top speed limiter cuts in before getting a full pull. Some guys do it in 4th anyway and just go with their highest reading. I did it in 3rd to get a full pull, but am concerned that my results are a bit less than what it is really putting down. I regret not having one pull in 4th to compare.

What do you guys typically do with your M's - run it in the highest gear that lets you hit redline or just use 6th? And has anyone run pulls in different gears to compare readings?

Thanks.

PS - Forum, sorry for the mini-hijack.
 

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I had mine dynoed recently and I got 408 rwhp for the highest pull. We did runs in 4th, 5th and 6th gears and I think 6th gear got the best result. Everyone else is right that 392 rwhp is very low. Even my 408 is low when compared to other numbers I've seen. My car is stock with stock wheels and the charcoal filters still installed so I'm thinking or at least hoping, that it'll be closer to around 420 rwhp with the filters removed.

As another point of comparison, Simon's M5 from Evosport had a baseline number of 413 rwhp but not sure if that's with or without the charcoal filters removed.
 

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I had mine dynoed recently and I got 408 rwhp for the highest pull. We did runs in 4th, 5th and 6th gears and I think 6th gear got the best result. Everyone else is right that 392 rwhp is very low. Even my 408 is low when compared to other numbers I've seen. My car is stock with stock wheels and the charcoal filters still installed so I'm thinking or at least hoping, that it'll be closer to around 420 rwhp with the filters removed.

As another point of comparison, Simon's M5 from Evosport had a baseline number of 413 rwhp but not sure if that's with or without the charcoal filters removed.
Thanks. Do you happen to remember whether 6th was "much" better than 4th or 5th? If it looks like 2 or 3 hp, then I don't really care. If the difference was 10 hp, then I am going back to the dyno for a 4th gear pull.
 

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They did about 7 runs on my car and the range was from 401 to 408 rwhp. I forgot which gear got the 408. Check out this link: http://www.m5board.com/vbulletin/showthread.php?t=94511

Adam from EuroElites was the one that did my dyno and looks like he confirmed that 6th gear gave the best number.
 

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1. Since the suspension was installed I now have a clicking noise that is coming from the rear of the car. It is the loudest when EDC is turned off and I have to be going over a bump... a speed bump at low speeds produces the noise the best. I was told by the installer to drive the car a little and make sure everything seats correctly. The radio and AC must be off to hear it as well. It is very annoying... anyone else have this issue? The installer toke 3 hours to completely go over the installation and couldn't find anything, but he did agree the noise is not normal. Dinan said it maybe the progressive springs in the back and they have only heard of one other case of this happening.
If they've only heard of one other case, it would be mine. I suspect they're in convenient denial. I had the same problem and it drove me crazy, though I freely admit I am sensitive to NVH and often drive without the stereo on.

Anyway, Luis at Dinan sent me these:

dinan-solution  137.jpg

Which go over every other coil on the bottom end of the rear springs. It solved the problem for me.

The factory springs have foam rubber covers on the top half of the springs for this reason; in my opinion it is an oversight on Dinan's part that they didn't include these as standard.

Call Dinan and ask for the coil spring insulators. You can install by simply jacking up each rear corner of the car.
 

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I agree on the baseline looking a little low. Here is my baseline dyno performed at K&N on a Dynojet. Charcoal filters were removed. No other mods to anything on the car. The dyno chart indicates that ODO = 2466 miles, but I think I had more like 4000 at the time. Peak RWHP was 431, torque 317.

If you do a little math and assume 15% drivetrain loss, than 431/.85 = 507hp, and 317/.85 = 373lb/ft of torque at the crankshaft. If you assume 18% loss as has been discussed on other threads and seems to be more accepted, then 525hp and 387lb/ft.

Edit: My dyno runs were in 5th gear, the highest gear you can use and go to redline without hitting the speed limiter (unless you have that removed). Otherwise, 6th gear is ideal because it's the closest to 1:1 ratio on the tranny.
 

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Discussion Starter #10 (Edited)
If they've only heard of one other case, it would be mine. I suspect they're in convenient denial. I had the same problem and it drove me crazy, though I freely admit I am sensitive to NVH and often drive without the stereo on.

Anyway, Luis at Dinan sent me these:

View attachment 40327

Which go over every other coil on the bottom end of the rear springs. It solved the problem for me.

The factory springs have foam rubber covers on the top half of the springs for this reason; in my opinion it is an oversight on Dinan's part that they didn't include these as standard.

Call Dinan and ask for the coil spring insulators. You can install by simply jacking up each rear corner of the car.

Thanks for the response.... I talked to Sean at Dinan and he said the same thing. So I am going to put them on this week and I will report back.

Can you describe the sound? For me it's like sharp clank noise when the spring is fully compressed, with EDC off it is the loudest.

I aslo talked to him about the mufflers and how to make them look a little better. He said to have them polished at a local body shop. I am going to make some phone calls and see how much it would be to do this... Has anyone else done this to the Dinan mufflers?

The 392HP on the dyno does seem low to me.... I will take the car to another local shop and get a comparision, I was not present when the Dyno was done so who knows; A low baseline dyno could be a good way to show HP gains on performance parts that shop installs.
 

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Thats good info on the coil covers - I plan on getting the Stage II setup and will make sure they include them with the order.
 

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As already said DYNO DYNAMICS dyno's do read lower than dynojet so the numbers are fine. Also its a dyno, its not gospel because the variances can be quite large even among the same type of machine. Its also foolish to guestimate the crank hp from a rwhp dyno as its all simply just a guess.

FYI here is something to compare it to.
http://www.powerchipgroup.com/images/Dynographs/Bmw0209 Peter White.dyno.jpg
 

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As already said DYNO DYNAMICS dyno's do read lower than dynojet so the numbers are fine. Also its a dyno, its not gospel because the variances can be quite large even among the same type of machine. Its also foolish to guestimate the crank hp from a rwhp dyno as its all simply just a guess.

FYI here is something to compare it to.
http://www.powerchipgroup.com/images/Dynographs/Bmw0209%20Peter%20White.dyno.jpg
Digger - If I am reading your graph correctly, your AFR is steady at about 11:1 the whole run. A little on the rich (but safe) side. Do you know if that is typical for an M5's engine tuning?

Forum83 - see if you can get graphs with your AFR's. It will allow you to see if your car may be running a bit "richer" than others. No secret, one way to unlock power is to remap the ECU to keep your AFR's closer to 13. That is one of the things computer upgrades do.

And as Digger said, we are really just guessing when we try to figure out drivetrain loss. A difference of 3% (15 - 18) makes for a huge variation. All you can really hope to tell is if your car is within the range of average rwhp for its kind.
 

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I have always heard the drive train loss is 18%.
 

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Digger - If I am reading your graph correctly, your AFR is steady at about 11:1 the whole run. A little on the rich (but safe) side. Do you know if that is typical for an M5's engine tuning?

Forum83 - see if you can get graphs with your AFR's. It will allow you to see if your car may be running a bit "richer" than others. No secret, one way to unlock power is to remap the ECU to keep your AFR's closer to 13. That is one of the things computer upgrades do.

And as Digger said, we are really just guessing when we try to figure out drivetrain loss. A difference of 3% (15 - 18) makes for a huge variation. All you can really hope to tell is if your car is within the range of average rwhp for its kind.

its not my car i just found it online, but it is on the rich side for a NA probably from the factory to keep it safe i would assume and its probably part of reason for the poor fuel consumption figures assuming its also a bit richer than normal at part throttle where most mileage is done. I would have though a low 12 AFR would be normal from the factory though.
 

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my car was stock at the time.

it pulled 429.8 RW HP
which was like 502HP when converted
he said it is normal on BMW to loose about 70 HP in the driveline.
 
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