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Thread: Back to the 3.23? thoughts?

  1. #1
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    Back to the 3.23? thoughts?

    Hey All? Hope all is well, sorry haven't been to involved on the forums in a while. Life is in the way..Anyway, Wanted to get thoughts and input from the group,


    as my coupe has evolved through the years, the first major need was a Transmission, (issues with 2nd gear) so we installed the Euro 6 speed and switch the diff to the 3.73.
    later came the super charger. but I kept the 3.73 in. of course, 1st gear is to short but beyond that has been fun to drive


    NOW, the old 3.73 is starting to whine and make some noise, Guessing it's on the way out. Haven't check it out yet, My plan is to put the original 3.23 back in.


    QUESTIONS:

    1) Any thought on how that will be matched with the 6 speed? to low in 6th gear or anything.

    2) any recommendation for the old 3.23 needing refreshed or updated (other than fluid) it's my original, with 65,000 miles on it. Should I look for something in between or go lower.

    3) Anything else while I'm there (other than check the subframe and spot welds or Randy's kit... some day)


    thanks in advance for the input!



    Brian

    Active HKS Stage 1 S/Crrrrr: m50 intake: Euro Oil Cooler: AA Exhaust: H&R/Bilstien

  2. #2
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    I have an S54 with the stock 3.15 and 6 speed and it's super awesome on the highway and still moves around town.

    Your s/c setup should give somewhat similar power levels, so with a 3.23 I imagine you'd have plenty of pep. It won't have the same neck-snapping acceleration as with the 3.73 but it'll be offset by shifting a lot less. And you can use first gear again, so you gain a lot of drivability back

  3. #3
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    Since you have the 3.23 already, I would swap it back in and give it a try. With added torque of the FI, I think you will be happy though it will feel a bit sluggish until you get use to it again. I would also use studs to ease the reinstall process. Lining up those top bolts on the carrier to Differential is a pain in the ass if the carrier is sill in place on the car.
    The studs appear to make things a lot easier. Note, I do not use the studs as the carrier is always out for full inspection when the diff is out of FrankenCoupe.
    Dan "PbFut" Rose

  4. #4
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    The 3.23 should feel great with the FI motor.
    The studs will help with the install, but theyre actually still not easy to fit correctly - theyre flat on the end, and the threads catch on the sheetmetal.
    I actually made some custom locating pins with cone ends which helped tremendously.
    Fit the diff into place, then pull each one out and replace with an OEM bolt.
    I am shocked that no one appeared to make a set of these tools.

    IMG_20180816_185051.jpg

    IMG_20180901_123512.jpg

  5. #5
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    A little trick I learned the hard way, if you lightly bolt up the bottom two bolts. Then slowly tighten them up just a bit, the top two holes will line up on their own. Without all the struggle.
    Built S52 w/Dinan ISR-3 kit, NickG Stage 2+ Tune, Dinan Vortech V2 Supercharger, Dinan Air to Air Intercooler, Dinan CAI, Porsche 803 HFM, Buldogge 6" crank pulley, Griptec 2.90" blower pulley, Eurosport UD pulleys, Dinan 3.38 Diff, Dinan front/rear Swaybars, Dinan springs, Koni Yellow Sport Struts, Ground Control end links, South Bend Clutch Stage 3 Organic, AASCO Light Weight Flywheel 18.5#, Zionsville Radiator & Oil Cooler, Riot Racing BBTB, Schrick Intake Manifold, 42# Injectors, Schrick cams 264/256, Forged Wiseco pistons 9.0 comp., Forged Eagle rods, Supertech dual valve springs & valves, VAC crank & bearings, Supersprint mufflers, Euro Z3 midpipe, Raceland euro headers, Walbro 255, Bevauto ignition coils, Vortech Mondo bypass, Bailey Diverter DV30, Ireland Rear Subframe Bushings, Mason Engineering Strut Brace, Mason Engineering Clutch Petal, Apex 18" EC-7 Wheels, Full Custom Sound System, two trunk lids (with & without OE spoiler), Hardtop, Trunk full of AK's...

  6. #6
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    Back to the 3.23? thoughts?

    3:38 from automatic from 1996+ E36M3 Sedan/Convertible comes to mind but with a Supercharger, perhaps a 1995M3 3:15 is in order.


    Sent from my iPhone using Tapatalk

  7. #7
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    I have the 3.23 with the 6 speed on my stock 3.2 and I love it. Personally, I never got the 3.73 thing, especially with forced induction. 1st year is basically useless and then, in essence, you are right back to a five speed. You will love the 3.23 and you will thank yourself the next time you are on the highway for more than 10 minutes. I did an two hours yesterday and was cruising at a comfortable 2600-2800 rpm at 75-80 mph.
    Last edited by Wertles; 09-12-2018 at 08:32 AM.
    1999 M Coupe Boston Green, Beige, H&R/Bilsteins, Underdrive Pulleys, Euro 6 speed, UUC SSK and Randy Forbes in the back
    2002 2.5 Z3 roadster Oxford Green, auto, all stock
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  8. #8
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    Quote Originally Posted by bluptgm3 View Post
    3:38 from automatic from 1996+ E36M3 Sedan/Convertible comes to mind but with a Supercharger, perhaps a 1995M3 3:15 is in order.


    Sent from my iPhone using Tapatalk
    You can't use E36 diffs in Z3's

  9. #9
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    I'm on a 3.70, can't wait to go back to my 3.46, or even 3.15 with a S/C, any highway drive is at 4200, plus I hit the rev limiter at 54 mph on AX courses,, and don't want 3rd gear for 40 yds., my personal trick for those subframe diff. bolts was a hole saw through the floor and cheater bolts(tapered tips), the CP gun does them
    both in 4 seconds!

  10. #10
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    Allot of bro-science and number crunching show the 3.46 and a 6-gear trans to be just about perfect.
    Built S52 w/Dinan ISR-3 kit, NickG Stage 2+ Tune, Dinan Vortech V2 Supercharger, Dinan Air to Air Intercooler, Dinan CAI, Porsche 803 HFM, Buldogge 6" crank pulley, Griptec 2.90" blower pulley, Eurosport UD pulleys, Dinan 3.38 Diff, Dinan front/rear Swaybars, Dinan springs, Koni Yellow Sport Struts, Ground Control end links, South Bend Clutch Stage 3 Organic, AASCO Light Weight Flywheel 18.5#, Zionsville Radiator & Oil Cooler, Riot Racing BBTB, Schrick Intake Manifold, 42# Injectors, Schrick cams 264/256, Forged Wiseco pistons 9.0 comp., Forged Eagle rods, Supertech dual valve springs & valves, VAC crank & bearings, Supersprint mufflers, Euro Z3 midpipe, Raceland euro headers, Walbro 255, Bevauto ignition coils, Vortech Mondo bypass, Bailey Diverter DV30, Ireland Rear Subframe Bushings, Mason Engineering Strut Brace, Mason Engineering Clutch Petal, Apex 18" EC-7 Wheels, Full Custom Sound System, two trunk lids (with & without OE spoiler), Hardtop, Trunk full of AK's...

  11. #11
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    If you're not already familiar, the EndTuning gear ratio calculator is a wonderful tool:

    http://www.endtuning.com/gearratios/

  12. #12
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    I'm S52 supercharged with a 6sp. I've played with 2.93, 3.15, 3.23, and 3.46. To me and my usage, the 3.23 was the worst. I found myself between 2nd and 3rd in a lot of cornering (aka exit ramp) situations. The 2.93 made 1st gear very usable, but not 6th. With the current 3.46, 1st is a bit traction limited, but 6th can be used from 60mph on up.


    /.randy

  13. #13
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    Thanks for all the feed back, as usual very good info, thats why i always look to you guys for guidance.
    Always get good/bad...pros and cons. And reinstallation help to. I like the studs. For install!!

    Since i have the 3.23. It going back in and see. We can alway go to 3.46.


    Quote Originally Posted by Wertles View Post
    I have the 3.23 with the 6 speed on my stock 3.2 and I love it. Personally, I never got the 3.73 thing, especially with forced induction.
    Yea, the 3.73 was good with the 6 speed, but the supercharger came after.

    QUOTE=rf900rkw;30104716]To me and my usage, the 3.23 was the worst. I found myself between 2nd and 3rd in a lot of cornering (aka exit ramp) situations.[/QUOTE]

    This is the type of issue I'm worried about =(, but will have to see. Can always look for a 3.46. Not against changing again. And again.

    Thanks for all the input from the group.
    B!

  14. #14
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    Somewhat on topic.... Are the LSD clutch mechanism interchangeable between an E30 3.73 and an Z3M 3.23?

    The 3.73 has been rebuilt new clutches with an additional clutch added. If I put my 3.23 lsd back in, I would like to swap in the refreshed LSD.
    -Phil

  15. #15
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    Yes, but correct setup can be tricky. There are many on this forum who have done their own clutch packs. Changing the gears are simply swapping ring and pinion while in there, but setting lash is critical. Especially on track used cars. Get it wrong and if the pinion gear walks up the ring by the tiniest amount, you will grenade the internals. Ask me how I know. $$$$
    Dan "PbFut" Rose

  16. #16
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    somewhat OT

    y even bother w/ a 6 speed?...I mean how is how 5th and 6th even usable.......?....wouldnt either suffice?...but both?

    I never got/understood 6 speeds.....

  17. #17
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    Quote Originally Posted by jrkoupe View Post
    somewhat OT

    y even bother w/ a 6 speed?...I mean how is how 5th and 6th even usable.......?....wouldnt either suffice?...but both?

    I never got/understood 6 speeds.....
    Why have a 5 speed then? Don't 4 speeds accomplish the same goal? Why even have 4, when you can have 3? Unless 3 is too many, just run 2 gears. Although really the only 2 gears you really need are R and D.

    The 6 speed boxes are basically the same in gears 1-5, with 6th being an overdrive. This allows you to run a shorter diff ratio to enjoy the performance/acceleration benefit while cruising at the same rpm on the highway. For a track car its pointless, for a street driven car it will maintain drivability after swapping diffs without sacrificing anything. Or run a 6 speed box without swapping a diff and enjoy better highway economy due to the overdrive 6th gear.

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  18. #18
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    Back when I was about to change the 4 speed to a 5 speed in the E-type I owned, discussion came up about how every engine has a sweet spot. Running lower revs on the highway does not necessarily translate to better economy. After I changed to the 5 speed, I don't recall that my mileage improved, but I surely did like the decrease in engine noise at the lower revs.

    Shortly after I bought the M, I considered installing a 6 speed, but the car is relatively quiet in 5th gear on the highway. With mileage about 27 mpg, it didn't make sense to me to spend the money.

    Has anyone who has replaced the 5 speed with a 6 speed and kept the original diff reported greater economy on the highway?
    Wayne

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  19. #19
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    Quote Originally Posted by rasmuw View Post
    Back when I was about to change the 4 speed to a 5 speed in the E-type I owned, discussion came up about how every engine has a sweet spot. Running lower revs on the highway does not necessarily translate to better economy. After I changed to the 5 speed, I don't recall that my mileage improved, but I surely did like the decrease in engine noise at the lower revs.

    Shortly after I bought the M, I considered installing a 6 speed, but the car is relatively quiet in 5th gear on the highway. With mileage about 27 mpg, it didn't make sense to me to spend the money.

    Has anyone who has replaced the 5 speed with a 6 speed and kept the original diff reported greater economy on the highway?

    I swapped out my five speed for a six speed and kept the stock 3.23 gear ratio. For me, it was perfect. I never got why people put a six speed in, a 3.73 rear end in, and then found first gear to be useless. To me, that is spending a whole lot of money to create a five speed which you already had. For me, six gear was solely for the purpose of highway cruising. It did lower my RPMs by about 600, it quieted my interior quite a bit, and increased my highway cruising by about 4 mpg. I did not change my rear end ratio as I found the stock set up very convenient while doing track days at Walkens Glen International. If I had gone to a shorter gear ratio, I would have added shifts in to areas that would have only slow me down.
    1999 M Coupe Boston Green, Beige, H&R/Bilsteins, Underdrive Pulleys, Euro 6 speed, UUC SSK and Randy Forbes in the back
    2002 2.5 Z3 roadster Oxford Green, auto, all stock
    2013 Ram 3500 Crew Cab Dually 385 HP, 850 ft lbs torque at 1600 rpm, all stock and staying that way
    2004 Mini Cooper Chili Red, daily driver, modified almost daily

  20. #20
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    Quote Originally Posted by rasmuw View Post
    Has anyone who has replaced the 5 speed with a 6 speed and kept the original diff reported greater economy on the highway?
    World of difference between an old e type and our modern cars. Id be surprised if anyone isnt getting better mpg with a 6 speed (assuming same diff ratio). The only way I think theyd get worse mpg is if it moved them into an rpm that would lug the engine. But realistically its moving from like 2800rpm to 2400 or 2300... Still well within the powerband

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