Harrop 2300 supercharger to Optimiser 6500

[Plasnart]

Jeez Phil, super glad you got out of that relatively lightly.

What seat-type nuts are you using on the alloys? Use the tapered nuts on steel rims, and flat seat nuts on the alloys.

100 ft/lb torque.

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[PeeBee]

Jeez Phil, super glad you got out of that relatively lightly.

What seat-type nuts are you using on the alloys? Use the tapered nuts on steel rims, and flat seat nuts on the alloys.

100 ft/lb torque.

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Pretty sure the taper units. The factory rims are set up or have a taper I think, will have a look tomorrow. Either way I need a guaranteed solution. I will make contact with Nissan and PAP on monday to get some answers.

Thing is the studs snapped, the nuts were not loose, I went back to the roundabout and picked them up, all studs broke at the same point and with no damage to the rim.

[Plasnart]

Thinking out loud here. Are those studs genuine Nissan or aftermarket? If they’re aftermarket they may not be up to the shear force applied by your loaded pod? Dunno if there are different load ratings for studs? The fact they all failed at once says to me that as soon as the first one went, the rest couldn’t bear the additional shear force applied to them?

Were the studs high tensile or mild steel? I have absolutely no idea if they’re available in both forms, but my understanding (and I may be wrong please correct me if you know) is that high tensile fasteners are only stronger in tension, not shear. Mild steel better in shear. More plastic, less brittle.

[PeeBee]

Thinking out loud here. Are those studs genuine Nissan or aftermarket? If they’re aftermarket they may not be up to the shear force applied by your loaded pod? Dunno if there are different load ratings for studs? The fact they all failed at once says to me that as soon as the first one went, the rest couldn’t bear the additional shear force applied to them?

Were the studs high tensile or mild steel? I have absolutely no idea if they’re available in both forms, but my understanding (and I may be wrong please correct me if you know) is that high tensile fasteners are only stronger in tension, not shear. Mild steel better in shear. More plastic, less brittle.

The studs are all nissan genuine. You are right the higher tensile bolts dont offer anything in shear that helps. I am thinking the bolts may have been installed with a rattle gun and stretched past their elastic limit when they were installed into the rear axle hub. The reason being the studs were replaced all the way around when the new discs went on. I am sure of this because the front studs are from a GU Patrol to suit the Willwoods, so i had the rears replaced as well with the standard rears Nissan studs. All this is guessing. Tomorrow i am going to put the rear axle over the scales and see what load its running at.
I am going to be asking PAP the same questions around the availability of more ductile higher shear studs tomorrow, plus about the nuts for the factury GU4 alloys. If I cany get a satisfactory answer I might change the all terrain tires over to steel rims for the Madigan.

[Plasnart]

Mate, personally I would change over to steelies, but that’s just my preference. Pros and cons for each. Steelies = higher unsprung weight but more malleable and forgiving when out the back of nowhere. At low outback speeds the higher unsprung weight is worth it IMO only.

Edit: At low outback speeds there’s not much chance of an alloy splitting up either. I might just have an old mindset there.

Probably wouldn’t run alloys in the Baja 1000 though. There, I feel better now.

[PeeBee]

Mate, personally I would change over to steelies, but that’s just my preference. Pros and cons for each. Steelies = higher unsprung weight but more malleable and forgiving when out the back of nowhere. At low outback speeds the higher unsprung weight is worth it IMO only.

Edit: At low outback speeds there’s not much chance of an alloy splitting up either. I might just have an old mindset there.

Probably wouldn’t run alloys in the Baja 1000 though. There, I feel better now.

The Nissan Factory alloys are very sturdy, unlike the massive range of look good street crawler alloy rims or rims developed well before computer FEA was avail. I dont have any concerns about the structural integrity of the factory alloys, however the weight is a valid comment. Do you have a brand or style you know of that are well made? @MB, whats your spin on this - I know you dont like alloys, but what is the brand of steely's you use?

[Plasnart]

Genuine Nissan GU steelies. You’ll find them cheap 2nd hand online.

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[mudski]

The Nissan Factory alloys are very sturdy, unlike the massive range of look good street crawler alloy rims or rims developed well before computer FEA was avail. I dont have any concerns about the structural integrity of the factory alloys, however the weight is a valid comment. Do you have a brand or style you know of that are well made? @MB, whats your spin on this - I know you dont like alloys, but what is the brand of steely's you use?

ROH Trak 2 Steelies are the best in my opinion Phil. I've seen pics of the cheaper Chyna made steelies literally falling apart.

[PeeBee]

Spoke with PAP this morning about stud strength options and applicable nuts.

The factory studs are the go, however their aftermarket studs are 'marketed' as being stronger and cheaper than the factory units, however there are no actual numbers to back up the claims, so I went factory. I am going to push the studs I installed out and reinstall with a more manual process to reduce the incidence of tensile over reach on both rear wheels.
I also confirmed the tapered nuts are the right ones for the GU4 alloys, so have purchased another complete set of new factory nuts with the open ends so the stud projection can be passively monitored as opposed to fitting the ones with the closed ends. The open ends are the ones used on utes with steel wheels also.
Surprised also the replacement rotor from Castlemaine Rod Shop arrived at 9am, only ordered it at 4pm yesterday - brilliant service.

[PeeBee]

Genuine Nissan GU steelies. You’ll find them cheap 2nd hand online.

IMG_0585.jpeg

Must be 17" rims to clear the Willwood Brakes, otherwise I would have gone this way instead of the alloys to begin with. I am struggling to find the value to torque the studs to - 6 manuals, internet search, simply no values. Going to have to go back to first principles I think working backwards from max allowable tensile stress I think - boy this is going to be a deep dive into my engineering design past!!!