zev

Great advice. Thanks Cary.

Wow, mostly pro-injection!! Anyone else who wants to contribute I’m all ears. also one other question… if my Webers are 45 with 38mm venturis should the ITB’s be sized at 45 also?

Hey All! I have a 72Z with a 3L Rebello stroker and triple Weber 45’s. The thing absolutely rips, but at low speed I have some drivability issues that I haven’t been able to tune out and I think that’s just the tradeoff of running DCOE’s. I’m considering working with chris at Godzilla raceWorks to have him install their Bosch ITB fuel injection setup but I’m curious how this will affect the overall power and throttle response. I don’t have a ton of experience with fuel injection but my assumption is that the car will have much improved drivability with the tradeoff of the gut-punch immediacy of the Webers? Can anyone advise me as to what the downsides are to making the switch? Thanks.

Hey Friends, I’m hoping people can offer some insights on a tuning issue I’m having with my 45 DCOE’s The car is a 72 240 with a rebello 3L stroker. Dave strongly suggested using the Chinese knockoff FAJS carbs, saying the machine work on these was much better than what he had seen coming directly from Weber, so that’s what we went with. He tuned the motor on his dyno and it runs beautifully all through the rev range with one big exception. Right at “tip-in” when I’m transitioning from fully closed throttle to say 1/8 or even 1/16 throttle there is ZERO progression, meaning that the throttle is either on or off, and this happens regardless of speed and RPM. Off the line I have to feather the clutch to keep the transition smooth which is fine, but if I’m heading into a corner and transitioning from the brakes to the throttle, there’s no way to get back on throttle without a big jerk, which in turn greatly upsets the suspension of the car. It feels like I have to overcome so much vacuum at the petal that there’s just no in-between from on or off throttle. So far I’ve tried bigger pump jets and tried blocking the economizers at the bottom of the float bowl and that made zero difference. I don’t think the issue is in the pilot jets since it doesn’t even feel like I’m getting into the pilot jet yet…it’s literally just the transition from fully closed throttle to ANY amount of throttle no matter how small. These carbs have 5 progression holes and Dave recommended drilling one of them out slightly, but before I go that route I wanted to see what other people think. I’m all for switching to genuine Webers if that would help, but both Dave Rebello and Dave at Pierce manifolds said the FAJS carbs are every bit as good. This stumble greatly affects the drive ability of the car so I’ll try anything to get it solved. many thanks.

Thanks all! I think based on the feedback here I will just stick with my 15x8 wheels and 225/50/15 tires instead of trying to punch out to a bigger size. Seems like the general consensus is that the offset won’t works, so I’ll stick to what’s tried and true

Thanks, that’s a great call.

Exactly, I am hoping to achieve a slightly more deep dish look at the wheels which is why I am looking at a slight negative offset.

Thanks for the reply. I feel like I’ve been reading so many forum posts on this topic that I am about to go blind. If I look at wheels with positive offset that won’t give me the deep dish look though, since it would move the spokes even further towards the outside of the wheel, right? I guess the answer is that I just need to roll the fenders more to accommodate the negative offset. Does adding offset negatively impact handling for a street car?

Hey All, I currently run 15x8 Rota RKR's (0 offset) on my 72 Z. There was a small amount of rubbing front and back but I rolled the front and rear fenders VERY slightly and now they don't rub, but only just don't rub so it's pretty close. The problem is I just can't stand the look of the zero offset wheel so I'd like to swap these out, but I also hate the super stretched look. I don't mind a little stretch, but nothing crazy. Can anyone chime in about their experiences with a 15x9 -13 offset and tell me what tires you used and what the rubbing situation is like? Or any general advice here of what I might want to look at in terms of a wheel / tire package for a 15 inch rim? Here's a pic of my current setup with the 15x8's Thanks!

300-400 is plenty for an S30. Thing must be nasty.

Killer. Is that on al L28?

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?

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 😈

CLSD from a 2005 STI.

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!

I just decided to live with the play for now. I'm going to upgrade to the Giken LSD at some point and see if that helps.

Here are some pics. I'm no diff expert either but those do seem like clutch plates stacked up if you look at the closeup in the first pic. Also I apologize I misspoke about the direction the stub shafts spin. They don't spin in opposite directions, I just meant I was rotating them in opposite directions to feel how much play was present before the clutch engaged and stopped me, but they both rotate in the same direction. I've been thinking about the dog tracking video since this afternoon and decided to double check the printout from my last alignment. My current measurements in the rear are 0.11 degrees of positive toe (toe in) on each side (22 degrees total toe in) and a thrust angle of zero. I was under the impression a small amount of toe in is good for stability but I didn't consider that maybe improper toe could be the culprit. Does anything about the above measurement seem like it could cause the rear of the car to walk out suddenly under hard acceleration? If so, I'd love any guidance and I'll button this thing up, go get the toe adjusted and report back. Seems like a good idea to rule that out totally before installing the OSG unit. Especially since once it's installed I can't send it back!

Update. I pulled the diff out and there actually isn't much backlash at all (dial indicator coming tomorrow so I can get an exact reading) but there is definitely a good amount of play when I rotate the stub shafts in opposing directions. It's maybe a 1mm but it translates to what feels like way more play when I rotate the wheels in opposing directions. I can't find a spec on wether there should be any free play in the actual LSD unit, but I went ahead and ordered the OSG and I'll see if that has any play. If it's identical I'll probably send it back but if there is no play in the OSG unit I'll install. I'll report back either way. Also, I have had a professional alignment recently and there was no change in the rear end hop before/after, so I don't think dog tracking is to blame but I like where your head's at and definitely appreciate the input.

Hey All, So I drained the oil this am and got the rear cover opened up. The oil was VERY dark, but no shavings or particulate and nothing on the magnetic plug. I have a dial indicator coming tomorrow, but just did a quick test in the meantime. With the car up on jacks, when I rotate one wheel it will turn roughly 3-4mm before the other wheel starts to move in the opposite direction, so there is certainly some play but everything turns smoothly. When I rotate the driveshaft there is slightly less play (maybe 2-3mm) but still noticeable. Is the play primarily a result of backlash or could a bad clutch pack cause the slack? Should you even be able to feel ANY play when you rotate the wheels or driveshaft or should it feel 100% direct? I also looked at the half shafts but there is zero play there, so the slack is all coming from the diff. I put the car in gear up on jacks and asked my wife to let the clutch out abruptly, there's a distinct clunk which is the sound of the play before the slack gets taken up. Once it's spinning everything runs smoothly, but there's obvious initial play and the more abruptly she let out the clutch the more noticeable it is. Can't tell if this is clutch pack related, improper backlash or a little bit of both. JHM, I totally hear you about the OSG unit $$$. That said, I drive the car pretty hard and after the rebello at this point the OSG is a drop in the bucket. I never plan on selling this car so I'd rather have it dialed in 100% and just be a joy to drive so whatever it takes, as they say. I'm by no means made out of money, but this car is my only vice and my biggest hobby so I want to make sure the old girl has whatever she needs. I've been chasing this driveline slack forever, so I just want to get it squared away. If that means an open diff that's fine, but I believe my original 240z r180 was an open diff and it still had slack, so I feel like I've been there before.

Thanks for the replies. The tires are definitely the same size. The half shafts have new U-joints so there shouldn't be any play there, but I'm considering CV's at some point anyways just to tighten things up further. The car is street driven (street-thrashed, really) but not raced, autocrossed, etc so I was hoping I could get away with running the R180 but maybe not. I'm happy with the ratio on the STI diff, so if I stick with the r180 I'll snag the sti unit instead of the datsun one. Looks like finding a 3.9 in an r200 could be tough. I assumed that since STI's put down close to rebello power I could get away with it. All of that said, in your opinion do the symptoms I described earlier point to an issue with the diff? Can there still be a lag in engagement between sides on the diff even if the tires are not breaking loose and you're jus going from off to on throttle? Do you think upgrading to the super lock (either with the r180 or r200) and making sure the backlash is correct would solve the issue?

Resurrecting this thread because I'm desperate for answers. I have a 1972 240z with a Rebello 3.0L & Borg-Warner 5-speed from a 280zx turbo and the 04-05 sti CLSD. For the past few months I've been trying to diagnose an issue thats driving me insane. When I abruptly crack the throttle (in any gear, but much more noticeable at highway speeds or in corners) rear suspension becomes upset and the rear end of the car essentially jumps/hops out to the right an inch or two. When I say jumps, I don't mean like wheel hop but more like the rear of the car just abruptly wiggles out to the right slightly so it's not a smooth transition from off to on-throttle. It's really noticeable if I'm coming into a corner, I downshift then get onto the power again. If I'm already under slight throttle and I roll on additional throttle it's a non-issue, so it only happens during that initial transition onto throttle, especially when it's abrupt. I thought the issue was suspension related so I've been chasing it that way, doing all T3 components in the rear, but no change. Finally it dawned on me yesterday that it might be the diff. It almost feels like one of the rear wheels is engaging half a second after the other and it's causing the rear of the car to hop/wiggle out to the side when the throttle is applied. Does that symptom make sense for a CLSD? If so, what would cause this? I'm looking at the OS Giken Super Lock NS081HA above that John recommended. This is probably a stupid question, but if I want to maintain the 3.5 ratio in the STI r180 (that works better with the T5) can I install the Giken unit into my subaru CLSD or does it need to be installed into my original 1972 stock open diff r180? I'm not terribly familiar with how these work, so does the Giken unit have it's own gear ratio and just completely replace the internals of whatever r180 I install it into, regardless of wether I use my 1972 open diff or my 04 STI diff or does the ratio stay the same as it was from the factory after the Giken install? Many thanks,

I was thinking it looks more like an "Edna".

You mean the pilot bushing? It’s still in the end of the crank so that’s out unfortunately. Was my first thought also.

It was also bone dry and had no trace of any lubricant or oil on it.

Hey All, I'm doing some drivetrain work on my '72 240 and found this machined spacer sitting on the transmission jack and can't figure out what it is. Specifically, I had an oil leak from the rear main cap side seals which caused the clutch to get oiled and slip, so I pulled the tranny, clutch, flywheel, oil pan & rear main cap. It's possible this came off something else from an earlier project and just fell on the transmission jack, but I feel like I would have heard it rattling around when I carried the jack out of the basement. It also doesn't seem to be a part off the jack. Has anyone see this thing before? Thanks! Zev