zev Posted September 13, 2022 Share Posted September 13, 2022 Hey All, I currently run a Rebello 3L with an STI R180 and stock half shafts and have had this setup for about 5 years. The R180 was used when I bought it and it's always felt like it wasn't super tight. I checked the paint pattern on the gears and it was in spec, so I'm thinking the LSD unit is just worn out. I'd like to upgrade to CV's, so now I'm looking at different rear end options so I can do everything at the same time. The two routes I'm thinking are: The full T3 ford 8.8 setup with coilovers & CV's. I already have a bunch of T3 stuff in the rear, so they can actually build me a kit with only the parts I need taking into consideration what I already have. If I wanted to go crazy I could even add an OS Giken LSD unit to the used 8.8 diff. 🤘 https://technotoytuning.com/nissan/240z/complete-ford-88-rear-end-conversion-z-car OR I pull the STI R180 and go back to my stock datsun R180, add an OS Giken LSD and CV's to that unit. Dave Rebello sent me a dyno sheet that shows 320hp at the crank. Who knows if that's correct but assuming it is, is the 8.8 overkill or the better call here? Seems like a LOT of differential to squeeze back there and also requires notching the crossmember. I don't mind overbuilding the rear end if the 8.8 is the way to go, but just curious to hear what you all think. I just don't want to invest in CV's and a Giken unit for the R180 only to blow it up later. Thanks! Quote Link to comment Share on other sites More sharing options...
Derek Posted September 13, 2022 Share Posted September 13, 2022 Well as I always say, "no kill like overkill". I always look at this stuff from a risk standpoint. If you are qualified to setup a new LSD and ring and pinion then there is minimal risk. If you have to send it out well then there's one level of risk. That was part of my decision to go with a newer used Subaru R180. It also comes down to driving style. beat the crap out of it on every shift (I approve) then you would want to overbuild. Quote Link to comment Share on other sites More sharing options...
jhm Posted September 13, 2022 Share Posted September 13, 2022 Which LSD is it? STi diffs came with a couple different kinds. And just FYI...it’s completely normal for them to have a fair amount of play, even when “new’ish”. I’ve had that same setup for several years with my nicely built SBC (mine’s a helical center section.) Quote Link to comment Share on other sites More sharing options...
zev Posted September 13, 2022 Author Share Posted September 13, 2022 CLSD from a 2005 STI. Quote Link to comment Share on other sites More sharing options...
AydinZ71 Posted September 13, 2022 Share Posted September 13, 2022 +1 on how you will drive the car as described above. For road racing, the torque a 3L put out will be OK on the diff. That is for SUSTAINED (low impulse, no shock) torque on a light vehicle, where rev-matching between gears is standard process. A lightweight flywheel/clutch will already require you to baby the launch, as those clutches wear out fast. If you are launching with sticky tires and dropping clutches drag-race style, no... It will likely fail during a launch one day. Even an R200 may get dicey launching on grippy tires. Impulse breaks driveline components well before sustained steady-state stress. I learned this the hard-way by destroying a handful of R200's before I realized my driving style was the biggest culprit. Also, the CLSD having wearable parts will obviously require maintenance as a weak point, but I am not familiar which of the two center-sections (CLSD vs. helical) has more shock resistance. I have a 17' STI helical LSD in my car. It is inoperable 🤣 Quote Link to comment Share on other sites More sharing options...
Dat73z Posted September 13, 2022 Share Posted September 13, 2022 (edited) What does your trq look like? I have spoken to a few thay have dynod Rebello motors on chassis dynos. I will be one of them as well in a few weeks. Assuming a 20-25% correction factor, you're sonewhere around 250whp/wtrq. I think the 8.8 would be overkill for just about all driving conditions at those levels, but you do get the tunability benefits of the 8.8. Fwiw Edit: What trans are you running? I have a setup that had once carried the tires on a nitrous v8 (R200 SN) but the weak point in my system is the trans. I will grenade my trans before exceeding the limits of my diff. Edited September 13, 2022 by Dat73z Quote Link to comment Share on other sites More sharing options...
zev Posted September 13, 2022 Author Share Posted September 13, 2022 280tq and 320hp on his bench dyno.The thing freaking rips and sounds evil. I put an exhaust cutout in it too for hooligan mode, which is pretty much all the time. Yeah, I also think the 8.8 might be overkill since the R180 has served me well so far AND STI's run them with similar power and torque figures and seem to hold together ok. For the tranny...I've been through the gauntlet: Stock 4 speed...blew it up. later 5 speed...blew it up Turbo T5 NWC...blew it up S13... currently making noise and one burnout away from...blowing up. The next step is the Godzilla Raceworks CD00 swap which will also be the first new, not rebuilt tranny this thing will have seen, so I'm hoping that get it done. I'm sure it has nothing to do with my driving style 😈 Quote Link to comment Share on other sites More sharing options...
Dat73z Posted September 13, 2022 Share Posted September 13, 2022 Dude are you my twin? Pic of my car from like 2016-2018 timeframe Lol. Yeah if it was me I'd just run the r180 until it blows. Tbh I would still be running my sti r180 clsd but I found a buyer who wanted it all and my buddy was parting out his rear end to go with an 8.8 (turbo nitrous LS drag car). Maybe post it for sale and see if there's any interest at a good price while you keep driving it. With your driving style though it sounds like you've been blowing trans as a "fuse" before your rearend goes. So maybe after the CD something else would let go. Quote Link to comment Share on other sites More sharing options...
zev Posted September 13, 2022 Author Share Posted September 13, 2022 Ha, that's too funny man. That thing is so clean! Love it. So you did the 8.8 in yours? Did you do the T3 setup? Quote Link to comment Share on other sites More sharing options...
Dat73z Posted September 13, 2022 Share Posted September 13, 2022 I'm running a Q45 R200 SN 3.54 rear end. I think our #s are similar though, at 9PSI on Rebello's dyno my engine made 370HP @ 6k rpms, and 370 trq around 4k rpms. I've spun the R compounds in 2nd and going into 3rd. Our driving styles are different, I'm setting my car up for street and occasional HPDE targeting 3-400whp/trq. At 8psi or so I'm happy with the car as-is since I mostly like to go cruising with friends. Quote Link to comment Share on other sites More sharing options...
zev Posted September 13, 2022 Author Share Posted September 13, 2022 Killer. Is that on al L28? Quote Link to comment Share on other sites More sharing options...
Dat73z Posted September 13, 2022 Share Posted September 13, 2022 3.2 stroker turbo. I could get more out of it, but it's blowthrough. Have a thread in the turbo section of the build so far Quote Link to comment Share on other sites More sharing options...
zev Posted September 13, 2022 Author Share Posted September 13, 2022 300-400 is plenty for an S30. Thing must be nasty. Quote Link to comment Share on other sites More sharing options...
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