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ASR (or RPI) Nos or Dinan Stroker.

Ranger, note that I am giving props to the Nos by listing it first!:blink:
 

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1) 3.91 Diff = ab $3k
2) Headers = anywhere from $5-8k
I think NOS and the stroker will increase everywhere, while the diff focuses more on increasing tq and the headers help with tq and hp
 

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3.91 diff and headers...
Does anyone besides Laidback agree on the 3.91 differential? Is it a must have mod? I've read alot of posts about the issues with the dinan 3.91 but nothing about Evos diff except that it is great. On the other hand, although some people have praised Evos diff, they still changed it back to stock as it was hindering their top speed. When you come to think of it, is it worth the hassle & cost of removing the 3.91 diff for the sole benefit of high speeds? Personally, I'd prefer having a better low end torque rather than reaching top speeds faster. How many times would you actually hit high speeds 20, 30 times may be more, but for people who drive their cars on daily basis, I believe having a better low end torque is more beneficial.

I do appreciate your opinion in this regard.
 

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I'm not an engineer, so my opinion is strickly as an M5 owner. Our cars need more torque of the line. 1st gear is weak and under hard acceleration the car seems to bog. After changing to a Dinan 3.91 diff, the difference was drastic. As far as top end speed, the M5 tranny is able to accomplish the high MPH while still having more RPM's to go. If you are drag racing, the trap speed with the 3.91 is going to be lower, but your time is also lower. Stock diff gives a higher MPH trap speed because your 1/4 mile time is longer. Best mod for the money. Unless your running NOS and then you want the stock diff for the added horse power. Any Engineers care to explain?
 

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that was my thread , i loved the 3.91 all the way to the end !! i wouldnt get in this car without it !! i dont drag or go to the track i just wanted more around town and thats what i got !!

about 2 mo's ago when i got rid of the car i sold the diff to another member and i drove it around without it and it was just plain old slow !!

as per tightie's comments i'd say get the diff and pulley at the same time and them its game on !!

neil
 

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that was my thread , i loved the 3.91 all the way to the end !! i wouldnt get in this car without it !! i dont drag or go to the track i just wanted more around town and thats what i got !!

about 2 mo's ago when i got rid of the car i sold the diff to another member and i drove it around without it and it was just plain old slow !!

as per tightie's comments i'd say get the diff and pulley at the same time and them its game on !!

neil
OT, i saw your sig. How u like the E63? Eloy got scoop for you as well, if you don't already have one.:blink:
 

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ASR Gen II exhaust!!! Nice improvement down low and in the sound department as well.
Richie, as soon as I got the email notification that you posted on this thread, I didn't even have to look at the thread to read what you wrote! I should have known that ASR plug was coming!

JustBlaze -- I have heard nothign but good things ab ASR's exhaust. I'm getting my RPI Sec 1 and 3 put on in a week or so, I'll let you know if there's any improvement in the low end when I get her put on...
 

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Richie, as soon as I got the email notification that you posted on this thread, I didn't even have to look at the thread to read what you wrote! I should have known that ASR plug was coming!

JustBlaze -- I have heard nothign but good things ab ASR's exhaust. I'm getting my RPI Sec 1 and 3 put on in a week or so, I'll let you know if there's any improvement in the low end when I get her put on...
lol...I am officially an ASR WHORE!!!
 

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:rofl: so true bradah...

Got to be specific on headers:haha:, not all the headers give you low-end torque. More likely, equal-length headers like RPI, SS, new RDSport, or Turner.:blink:
The good thing about the upgraded diff is there is constant power across the band, no heat soak:hihi:
 

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NOS is generally only available "safely" from the middle+ of the RPM range, at WOT.

To generate more low end, the right exhaust system can be a good start, but a rule of thumb is the more air you flow out of an engine, the less low-end available (again, speaking in generalities)...reference the exhaust valves on many 1000 cc street bikes to increase low end via backpressure. The right header/flange system can fatten up the middle pretty good though.

A custom map with more aggressive timing/octan changes can help as well, but I don't know what proprietary software hacks are available here either.

Lower rear gears are hard to beat for storming the quarter mile, especially if you have the tires to apply all the earlier power in first/second gear. They really make heavy cars come alive. It also is useful to mask any big breather mods that may reduce low end punch.

I have yet to receive my M5 yet, so I can't comment on how it is out of the hole, but redline in first being 44 mph seems to be pretty "low" geared (I'm guessing short shifting lower RPM traffic trolling is where the stock package falls a bit short).
 

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I'm not an engineer, so my opinion is strickly as an M5 owner. Our cars need more torque of the line. 1st gear is weak and under hard acceleration the car seems to bog. After changing to a Dinan 3.91 diff, the difference was drastic. As far as top end speed, the M5 tranny is able to accomplish the high MPH while still having more RPM's to go. If you are drag racing, the trap speed with the 3.91 is going to be lower, but your time is also lower. Stock diff gives a higher MPH trap speed because your 1/4 mile time is longer. Best mod for the money. Unless your running NOS and then you want the stock diff for the added horse power. Any Engineers care to explain?
+1. I love the 3.91 diff.
 
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