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Discussion Starter · #1 ·
Are the stock parts really that good? I have searched for stuff like better intakes etc and find nothing.. Im planning on a exaust from andy in the future and was making my list up but really all I see are exaust and cams out there
 

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Since there aren't many 3.0s on this board, I'll take a stab at this. Although purely unscientific, borderline BS, my observations with my mods, in order of install have been as follows 1) Dinan CAI: minimal power increase, but nice sound 2) Dinan bored throttle body and software: still not alot of improvement, but elimination of throttle lag with the software is a big improvement 3) SS exhuast: now I'm feeling some extra power and great sound, engine feels like it's really breathing like it should now 4) Turner UDPs + CDV delete: hard to explain this improvement, made the car feel much more lively in a very good way. Alll together I feel very happy with these mods, all of the small gains have added up nicely. But if I had less money and/or more sense, I'd probably just do software, exhaust, and CDV delete. I think those three mods made the most noticable improvements and were the most bang for buck. good luck
 

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Sorry go a little off-topic, but on the subject of mods. for 3.0s, I think that a lower ratio diff. is probably one of the best mods, since we only have 3.07 Torsen LSD. Here are a couple options I'm weighing, 1) a 3.46 from a 01 - 02 auto Z3; 2) a 3.23 from a 99 - 00 M roaderster/coupe; 3) a 3.38 ring and pinion swapped/rebuilt into my current diff. Any thoughts of these options? What order would you put them in. Any leads? Thanks.
 

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Im here
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Discussion Starter · #5 ·
robrez said:
Sorry go a little off-topic, but on the subject of mods. for 3.0s, I think that a lower ratio diff. is probably one of the best mods, since we only have 3.07 Torsen LSD. Here are a couple options I'm weighing, 1) a 3.46 from a 01 - 02 auto Z3; 2) a 3.23 from a 99 - 00 M roaderster/coupe; 3) a 3.38 ring and pinion swapped/rebuilt into my current diff. Any thoughts of these options? What order would you put them in. Any leads? Thanks.
ahhh the 3.0 is only a 3.07 diff, yeah i might look into a 3.46
 

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robrez said:
Sorry go a little off-topic, but on the subject of mods. for 3.0s, I think that a lower ratio diff. is probably one of the best mods, since we only have 3.07 Torsen LSD. Here are a couple options I'm weighing, 1) a 3.46 from a 01 - 02 auto Z3; 2) a 3.23 from a 99 - 00 M roaderster/coupe; 3) a 3.38 ring and pinion swapped/rebuilt into my current diff. Any thoughts of these options? What order would you put them in. Any leads? Thanks.
forgive my ignorance here....doesn't changing to a lower ratio diff raise your RPMs at highway speeds? iirc, my car sits around 4K rpm at hwy speeds...

i have no idea what my gear ratios are and the 368s tool doesn't have those numbers for the 3.0 :bawling:
 

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Discussion Starter · #7 ·
mng said:
forgive my ignorance here....doesn't changing to a lower ratio diff raise your RPMs at highway speeds? iirc, my car sits around 4K rpm at hwy speeds...

i have no idea what my gear ratios are and the 368s tool doesn't have those numbers for the 3.0 :bawling:
Yes it will give higher rpms at highway speed but with a 5speed prob not a massive diff. but low end take off should greatly improve
 

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01silber said:
Are the stock parts really that good? I have searched for stuff like better intakes etc and find nothing.. Im planning on a exaust from andy in the future and was making my list up but really all I see are exaust and cams out there
There's been some good discussion regarding the 3.0 and CAI's on Roadfly... I recently installed the Conforti Intake Shark (CAI) and am quite pleased with the results.
 

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mng said:
forgive my ignorance here....doesn't changing to a lower ratio diff raise your RPMs at highway speeds? iirc, my car sits around 4K rpm at hwy speeds...

i have no idea what my gear ratios are and the 368s tool doesn't have those numbers for the 3.0 :bawling:
Your gear ratios Nick, are (1st to 5th): 4.21 / 2.49 / 1.66 / 1.24 / 1.0
And your final drive (aka Diferential ratio): 3.07

Adding to the list of possible differentials, there's also the 3.91 in the Z3 Roadster 2.5i for '01 and '02.

Several things will happen if a person went to a higher ratio differential:
- The car would launch off the line faster in 1st.
- Depending on which differential is swapped out, but most likely any of them would cause this.. you'd no longer be able to get to 60 mph in just 2 gears (one shift). It would take 3 gears (two shifts), and thus .. bragging stats would be lowered. But ironically, the car would feel faster (and would be).
- There would be more torque available at the bottom third of each gear, but, there would be less torque available at the upper end of each gear. Practical translation.. the car should feel more fun to take through the gears.
- When taking 25mph / 30mph twisties, 4th gear would suddenly be waaay more useful and fun, where as currently, it feels like too much of an RPM drop (opinions would vary on this).
- Cruising on the highway in 5th, the car would be running at noticably higher rpms. If it's just a weekender fun car... I would say this doesn't matter at all. If one takes long trips in their car... in my opinion this would be a big problem.
- You may not be able to hit the car's top speed any longer. Depends on which diffy is chosen. From memory, I recall that our cars are at about 5,500 rpm when they hit the 129mph govenor. Seems like some of the differential swaps.. you could still hit this mark ... with the engine running in the 6,500 range.

With bikes (bicycles) we do lots of climbing (Many hills around here). When building up a gearing set, I like to custom gear the bike (take the cog set apart) and use the lowest (easiest) gears I can get (larger cogs in back = easier to climb), but then replace the last few cogs with very high (smaller cogs) ones. I would never use these last few gears to climb with. But having them, means that I can ride in a fast peloton of cyclists and be able to stay in. Without that change out of the final gears, I would reach my max ability to spin the cranks, and then not be able to stay in the pack.

In my humble opinion, all sports cars are geared goofy. When.. have any of us ever "torn around for fun" in 5th gear? Never. 4th gear is it. The trannies on these cars should be geared with much lower 1 through 4 gears, and then have a very large / tall 5th gear for driving the highways. This could be accomplished by replacing the differential with a 3.46 or higher, and then replacing the 5th gear in the tranny with a much taller gear. The car would be emmensely fun to drive through the corners, and would cruise quiet and smooth on the highway in 5th.

But back to the differentials; If a person was really going to replace one, I would go with one of the two-ear differentials for the M's (can't remember which one now), and use Randy's two-ear setup.

:)
 

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Differential ratio swap:

Just as a point of reference, when I went from a 3.15:1 to a 3.73:1, the RPMs were only 500 higher in any given gear for the same road speed. The results of the ratio change only had upsides as far as I was concerned, or anyone else that I've talked to about it.
 

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Max, The Eurosport guys have a cam kit for you. Its complete with hardware and software. It works! Best engine mod I did. It rips thru the rpm now.
 

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went the DINAN route with CAI, TB, software and exhaust; feels and sounds good (had it dyno'ed to check improvements) but def waaay too expensive for whatever improvements were made. also just recently did the CDV mod and i am pretty happy with it (really doesnt do much to address the need for more power though).

i was also thinking about the diff swap and am leaning towards the 3.46 from our automatic brethren just for the fact that i dont want to deal with modifying the speed sensor. i know that highway speeds in top gear prob wont be to high (even though our speedometers maybe a little off ;)) but first gear (4.21) goes by way too fast for me even with our stock 3.07. makes a good launch a little tricky to pull off as is.

didnt see (prob missed) the cam kit from Eurosport specifically for our M54s. prob $3K+install :yikes:

philosophical rant-
im goin towards sinking more $$ into suspension upgrades to improve handing. i use the Coupe for auto-x and short road courses so this would be more beneficial to me and IMO for a 3.0i. dont get me wrong, i love more HP, its the natural tendency for all red-blooded males. but ive seen it as an addiction that can get carried away. a friend with a Z06 thinks his 400 horses isnt enough :rolleyes: short of forced induction or sprinkling the magical fairy dust BMW did with the new N52 3.0 liter, our M54s is as good as it can get with the minor mods available IMO. To each his own, but I chose the less addictive route :angel:
 
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