GT-RZ

The flat drive is a bad design especially when you look at the gears and see how little the wall of material is left on the gears. The more splines the better because as the number of splines increases the surface area increases and the size of the tooth decreases which means the overall minimum thickness of the gear has increased (stronger). Even the smallest amounts can make all the difference. here is a quick example i did for work: 'x' shear pin with a 15mm diameter produced a UTS shear loading capacity of 4.3 metric tons the revised sheer pin is 19mm in diameter and made of the same material which holds a max of 6.9 metric tons Now if you look at these gears (posted earlier) you can see how thick the gear teeth are but how small the minium thickness of the gear is. And where did it shear? in between each tooth. If that had lots of small teeth the minimum thickness could be doubled or tripled easily. The next problem is of course heat. You will all have seen the tiny splines (like on a three piece crank of a cycle) they are very small, maybe 1mm at the base of the tooth max but teeth like these would be no good in an engine as the smaller the teeth the smaller the components tolerances must be. That's why the toyota design is a win because they have done all the work for us and we just need to copy it! perfect. Not sure how many teeth they have but the 2jz has allot more than 8. The last problem is getting the material correct, and that's it. which is why i insist we go through the testing process! If they have readily access to 4140 and 4340 then go the 4340 it makes all the sense as 4340 is better at withstanding shock (like that of limiter bashing) didn't get time to proof read this i gotta run. hope it makes sense.

flutter if you have a BOV just means it's doing a crap job. Removing a BOV will give you flutter. Hard piping just amplifies any sound that would be absorbed by the plastic/rubber OEM stuff.

Still awaiting a reply in the group buy topic. Without any form of answer to the questions being asked i'm not very confident on buying considering these will be the first lot for testing. Id feel much more confident if they were made of 4340 not that 4140 is rubbish but why not go for the best? impact and tensile tests IMO are a must on a test piece of steel that has been tempered to the specifications used in this gearset/collar. On a side note who was it that got the standard gears tested for hardness??? Did it get done?

updates?

+1 on that. Makes me laugh when people tell me there import has only done 50,00k's

they are like $70 for a good one. I could not keep the factory lines running along the crossmember which acts has the OEM cooler. 34 x member in silvia.

I agree i think the drift engines get a really bad time!

there is a quote i like: speed costs money, how fast do you want to go? But i think this one is more appropriate these days: reliability costs money, how reliable do you want it to be?

They don't cost much. get one! id recommend getting a powersteering fluid cooler too as they are really cheap!

Generally things must be surface ground after nitriding due to the surface expanding unevenly. That is the gas can be absorbed at different rates in the material. However given that these are gears and not a bearing surface (like a crank) it should not matter as much. Cryogenic treatment is excellent in making material stronger. So you have a good mix. Nitriding does nothing for strength but makes the surface very tough and cryogenics does nothing for toughness but adds strength (re-aligns the grains correctly i believe) potentially Allows obviously a more plyable material to be used which IMO is a good thing when it comes to gears. GTR standard pumps would be the go imo! Looking forward to these, hopefully a cheaper cure to this problem. PS: How many splines are there going to be (sorry if this was mentioned earlier also) As obviously the more splines (think 10 splines per 25mm) the larger the surface area but with that comes smaller splines which requires smaller tolerances which may not be suited for the heat expansion that these gears will come under during the operation of an engine. Looking at the Supra design posted earlier in this thread would be a good way to go, not very many splines but it's clearly a tried and proven logic. PS: If possible 4340 is the superior material compared to 4140 but obviously it does come down to the manufacturing processes s available.

that's a bit worrying. splines are the best option imo without opting for a dry sump. using a splined system you can use a material that does not have to be as tough as the OEM system (which is very very tough but also brittle). Ideal gears will have the plastic deformation limit quite far from the UTS. As obviously the closer the plastic limit to the UTS the more brittle it is. Personally id rather the gears round themself off than sheer in to pieces. what material are these splines/gears going to be made off?

If your brakes are squishy then before you go out on a track do yourself and others a favour and get them blead!! check all your brake pads too and ensure all your fluids are up to scratch!!!! I think common sense prevails here. if you don't have enough money for an oil cooler then you don't have enough money for any upgrades as of yet so just ensure your car is in tip top shape as it is! Have fun.

But if you do it that way just pray that it doesn't destroy something that will cost you allot more to fix next time. you can get bargains on rods and pistons these days and if i was to leave it stock id at least be getting new rings/bearings and a hone.

Don't worry about dial bore gauges or digital bore gauges get a standard telescopic bore gauge. you'll need a set do do all the work your talking about and then a set of good micrometers. make sure you know how to use a bore gauge too... it's not as simple as hold it where you think is perpendicular. failing that use a ruler and have a guess

awaits splined collars + gears. preferably to fit standard GTR pumps since it's imo a waste of money buying an N1 to rip out the gears anyway.

my 2c is get them flow bench figures you mentioned before. If this was a worked and documented head from a reputable shop it would be gone by now. But no flow figures and no one knows if you have improved or decreased the effectiveness of this head. Allot of testing and experience goes in to the making of a well working head, not just if it 'looks like it will flow well'. Nissan did a very good job with the ports in the RB26 and it is not easy to enhance them significantly, but very easy to make things worse. That's why CNC ported heads are well sought after because people know EXACTLY what they are getting. 100% equal every time.

look for neo rods too, same thing and may be cheaper from the wreckers!

pretty high compression so should be fairly responsive!!

oh mybad i read it wrong! i was talking about exhaust manifolds as far as the dumps go i'm not sure. Id probably upgrade from the factory dumps regardless.

far out. talk about positive manifold pressure at idle lol... what power did you make/ where did it drop off??

i'm fairly sure the 32 stuff is the junk in terms of manifolds... 33 and 34 have better flow but i think the 34 ones were made in stainless???? really not sure.

what are your guys thoughs on the gt3082 as a medium between the gt3076 and the gt35? if i go either it will be 1.06 but obviously the option for twin scroll is only available for the gt35 as it uses the larger T4 footprint! Really anywhere between 350-400kw is perfect but nearer the >350 mark is more my goal. Engine is going to be running 8.7cr forged 26/30. will choose cams (possibly regrind) when i know what turbo i want response is paramount, rather that than the higher power figure. thoughts appreciated!!

have you considered the gt3082 1.06? seems to be the medium. If you want gt30 go the 1.06?

I wondered about this. Do you have two tensioners? Or the idler on the exhaust side and a tensioner on the intake side? I can't remember the post but it was suggested to keep an idler rather than another tensioner on the exhaust side for easier tuning. (obviously the 'new' drilled location for the intake side tensioner stud determines if you can get the correct tension with an idler and tensioner)

Refer to this thread: http://www.skylinesaustralia.com/forums/30...on-t285067.html page 2 or 3 i asked almost the identical question you did. I'm leaning towards the gt35 twin scroll (1.06 rear housing) but have not dropped the idea of the 3076 with the 1.06 housing, not considering the .86 anymore though.