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Discussion Starter #1
got the dinan 3.91 installed yesterday at motorworks west in wyckoff, NJ.

initial impression- this is a NEW [email protected]#$ it pulls a LOT harder in all gears and is simply amazing. what a great mod!!! I couldnt be happier with it. The RPMs are noticably higher at speed (of course!) but it just feels "right". In comparison, it felt too long legged before and now is a mean fighting machine at (mostly) legal speeds.

It has totally satisfied, for now at least, my never ending desire to accellerate faster. Wolverine posted before and after performance numbers from his GTech, which although do show an obvious increase in performance, do not reflect how much the "feel" changes in this car with the 3.91. The numbers just don't tell the story. Someone said that with the 3.91, in P400 it feels like it used to in P500S. This is pretty accurate! I cant help but think that this diff is what the car SHOULD HAVE from the factory! WOW!!! :7: its way more than a subtle change. Completely worth every cent! It would kill a stock M5, no problem.

next mod- dinan stage 2 suspension
 

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Discussion Starter #3
LI-M5 said:
im the one that said 400 now feel like 500 and its damn true

and you were 100% right! :cheers:
 

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How does P500 feel? How much does it cost installed again?

TIA
 

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extassy said:
How does P500 feel? How much does it cost installed again?

TIA
like a frieght train in the mid to higher rpm's.

and its $2499.00 plus install about another $450.00/$500.00.a great mod for the price.imo
 

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Is the 3.91 removable after installation so I can sell it? My car is leased so I wanted to make sure I can remove it before returning the car.
 

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labelexec said:
Is the 3.91 removable after installation so I can sell it? My car is leased so I wanted to make sure I can remove it before returning the car.
yes you can defenetly remove it but, because there is a core swap you'll be left with no rear.a new one from dealer is about $1600.00.

i to have leased my car and when the time comes i'll find somone probably from the board have them pay the labor, maybe throw me a couple of beans and swapp for thier stock one.

NEIL..
 

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The last time i was in your car we hit some mph i cant amagine how it is now congrats:M5rev:
 

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freddydi said:
got the dinan 3.91 installed yesterday at motorworks west in wyckoff, NJ.

initial impression- this is a NEW [email protected]#$ it pulls a LOT harder in all gears and is simply amazing. what a great mod!!! I couldnt be happier with it. The RPMs are noticably higher at speed (of course!) but it just feels "right". In comparison, it felt too long legged before and now is a mean fighting machine at (mostly) legal speeds.

It has totally satisfied, for now at least, my never ending desire to accellerate faster. Wolverine posted before and after performance numbers from his GTech, which although do show an obvious increase in performance, do not reflect how much the "feel" changes in this car with the 3.91. The numbers just don't tell the story. Someone said that with the 3.91, in P400 it feels like it used to in P500S. This is pretty accurate! I cant help but think that this diff is what the car SHOULD HAVE from the factory! WOW!!! :7: its way more than a subtle change. Completely worth every cent! It would kill a stock M5, no problem.

next mod- dinan stage 2 suspension

Thats great!!! Happy to hear this...I'm getting my Diff 3:91 and dinan stage 2 suspension installed next week friday at Habberstadt BMW. I cant wait!!
 

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DinodealM5 said:
Thats great!!! Happy to hear this...I'm getting my Diff 3:91 and dinan stage 2 suspension installed next week friday at Habberstadt BMW. I cant wait!!
Dino
Make sure to take before and after pics with the suspension. Would like to see how much it lowers the car.
 

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LI-M5 said:
yes you can defenetly remove it but, because there is a core swap you'll be left with no rear.a new one from dealer is about $1600.00.

i to have leased my car and when the time comes i'll find somone probably from the board have them pay the labor, maybe throw me a couple of beans and swapp for thier stock one.

NEIL..
Oh well what's $3000 to burn.
 

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bmwbonehead said:
Dino
Make sure to take before and after pics with the suspension. Would like to see how much it lowers the car.

Great idea...consider it done.
 

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freddydi said:
got the dinan 3.91 installed yesterday at motorworks west in wyckoff, NJ.

initial impression- this is a NEW [email protected]#$ it pulls a LOT harder in all gears and is simply amazing. what a great mod!!! I couldnt be happier with it. The RPMs are noticably higher at speed (of course!) but it just feels "right". In comparison, it felt too long legged before and now is a mean fighting machine at (mostly) legal speeds.

It has totally satisfied, for now at least, my never ending desire to accellerate faster. Wolverine posted before and after performance numbers from his GTech, which although do show an obvious increase in performance, do not reflect how much the "feel" changes in this car with the 3.91. The numbers just don't tell the story. Someone said that with the 3.91, in P400 it feels like it used to in P500S. This is pretty accurate! I cant help but think that this diff is what the car SHOULD HAVE from the factory! WOW!!! :7: its way more than a subtle change. Completely worth every cent! It would kill a stock M5, no problem.

next mod- dinan stage 2 suspension
I have to agree - the best 'bang for the buck' in terms of straight line performance - no question.

I also agree my numbers don't tell the entire story. Several of the 0-60 runs, and ALL of the quarter mile runs included an extra shift, cutting .15 seconds and several mph from the runs. If you take out the effect of the extra shift, here's what you get in both 0-60 times, and quarter mile times:

0-60 times, the Dinan is quicker by almost .2 seconds

Quarter mile times, the Dinan 3.91 is quicker than stock by .3 seconds and 4 mph trapspeed!

(You achieve these numbers by simply increasing the rev limit by 250 rpm!)

These really are huge differences, and I would guess it would take at least 50-60 additional crank HP to give you this kind of improvement. So you're right, P400 with the Dinan 3.91 should feel closer to P500 stock.
 

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Ok....

P400 pulls like P500....read it on many threads...

My question is : What does P500S feels like with the Dinan 3.91 vs. stock ?

other question:

other threads have discussed a software upgrade from Dinan for the 3.91...when is it coming out and why wer they going to do that again??

Thanks
 

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bavaria1 said:
Ok....

P400 pulls like P500....read it on many threads...

My question is : What does P500S feels like with the Dinan 3.91 vs. stock ?

other question:

other threads have discussed a software upgrade from Dinan for the 3.91...when is it coming out and why wer they going to do that again??

Thanks

P500s feels like P600:M5rev: :applause: :haha: :hihi: I don't think that the software will come out until spring time.
 

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Discussion Starter #16
EBuyuk said:
P500s feels like P600:M5rev: :applause: :haha: :hihi: I don't think that the software will come out until spring time.

haha exactly!

P500, with the dinan 3.91, feels as if there was a "P600". the difference you feel between p400 and p500, add that to p500 and thats pretty much what it feels like.
 

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bavaria1 said:
Ok....

other question:

other threads have discussed a software upgrade from Dinan for the 3.91...when is it coming out and why wer they going to do that again??

Thanks
Last time I heard it was to come out before the end of the year. Its needed because if you drive it in D mode and WOT it will bounce off the rev limiter because the sift point is based on speed and it will now redline at a slightly lower speed. Interestingly, the AA software upgrade increases the rev limiter yet those with the 3.91 and AA still bounce doing WOT in D mode.
 

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The problem is that the rev limiter is only raised by 250rpm. And that doesn't cover the 8% loss in speed for each gear.
 
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