Project JZA80

[damien]

Good call. I figure with the power level you're going for it would make up for the higher final drive anyway.

[TheGoodGuy]

As you were on the topics of diff's, the lower ratio diff would most likely be found mated with the auto transmissions, or is it vice versa? Also would the diff's on the auto transmissions have any inferior qualities in comparison to the those that would be mated with the 5spd/6spd manuals on the supra, feel free to elaborate on both model supra's if you got the info (mk3 & mk4).

Lastly is there any way by just looking at the diff's to tell the ratio's or the differences?

[SF5]

Ok first to answer the question of knowing the diff ratios just by looking at them.
1. On most differentials there are usually small imprints indicating the diff ratio. Ok now the diff ratio is a count of the teeth of the ring gear (which is the big circular gear which is attacted to the differential)and the number of gears on the pinion which is the smaller gear that is in direct contact with the Ring gear. So say you had 24 teeth on the ring and 6 teeth on the pinion ur ratio would be 4:1. I had to learn that cause of stupid mustang final gear upgrades.

THe higher the 1st number on the gear ratio the faster your intial acceleration would be which means the shorter your gears would also be.

Auto trannies tend to have higher ratio diffs because their gears tend to be longer since most come with 4 gears. So they'd have to have a taller ratio diff to get some decent acceleration. Mating a lower ratio diff would be good but can't imagine that being good on the clutches in the auto tranny, But I think if I have a big turbo on an auto I'd want a shorter diff to maximize my speeds in every gear. On the 240sx we use Q45 diffs since q45 diffs have 3.69:1 compared to the 4.08:1 (if you've driven a turbo 240sx sr20 or KA-T you'd be just annoyed by how short the gears are and how wierd it is to red line 5th)UMMm I don't like to be driven fast btw.

The diff usually are extremely stout on most JDM RWD cars,on the supra we did manage to break the Universal joint on the Driveshaft. So on that I'd say you're more likely to ruin and axle or tranny before you kill the diff. Also if the clearances in the diff are not met or to spec you will distroy it. And also L.S.D do tend to go bad as well but if they do say in a viscous type LSD then you're gonna end up with an open diff, with a torsen type going bad might mean broken gears inside there which will f*ck u up some.
They also carry oil which you change at schedule intervals. Front wheel drives also work on the same principle just that everythings in the case, differential and all. And Really really suck when you break something as we did with the Mazdaspeed Protege back in 2006-07.



MK3/MK4

If u have an 4.30:1 diff in your MK3 car you may want to convert to a 3.73:1 diff from a turbo MK3 to do your 1JZ or 2JZ swap using the R154 box.You'd be happier. IF PK180 was originally a 7MGTE that was black in posse then its a 3.73 so You're fine on that end. I'd just do a tranny oil change just to have peace of mind. You can punish the shit out of it. Just check to see if it has L.S.D, they came with locking and non locking diffs I believe,should be written on there somewhere. If it don't then upgrading to one would be neat, supras tend to pull hard between shifts especially the MK4. Some say its slip, some say its because of the unequal lengths in the rear axles. But they make a spool kit which makes it go str8 down the line similar to a welded diff. There is a certain dominican up here with an FDRX7 whose rear wheel seems to be hoping during turns (hinting at a spool or welded diff) car smell like gas falling out the exhaust lol. IT is not slow!

[TROJAN - X]

so its safe to say that you select a tranny and diff according to what yopu are building and applyin the car to..

example building a Drag supra u wud want to have the gears short but acceleration high..

i think that i grasp the concept alot more now....

cant remember reading this in the post anywhere but have u upgraded the brakes as yet to stop you with all that power being made /?

[SF5]

IT has the 97 upward big brakes on it. As for increased stopping I think something is wrong, previous owner had a race shop, but don't know what the f*ck they did the car had no brakes when we got it. And now the brakes work but I'd give them a 6/10 not very satisfied with the stopping power. Drag racing is a wierd sport, alot of variables you're racing against time not the person in the next lane. 60ft time, reaction time and Overall speed is what will net u good times. Most of the super cars 4 sec have fewer gears 1 or 2. So the gears are long so I'd have to think that the ratios are very low less time lost shifting gears etc.

[TheGoodGuy]

cool info, I'll have to get under that car and see. I dont think it was the PK180 of possie.

[SF5]

The installation has started,I have run into several problems, some big some small, but that's what happens when u doing an one-off setup. Anyhow we had a few ammendments to the order due to backorders and discontinued parts

Emanage Profec E-01 was discontinued and we couldn't find one so we went with Apexi AvC-R

The HKS CLutch Triple Plate was a six weeks wait since HKS-USA didn't have one in stock after the item was paid for at a distributor. So we went with RPS Bronze clutch and ACT Heavy duty Clutch Cover for a 900whp setup. Meanwhile the O.S Giken Quad Plate clutch is in the works (6-12week wait).

Now the intake manifold was designed we ordered wasn't wat we got, but to pay to ship it back would be too much trouble so we kept it. This one is designed for a gutted car with no power steering or fuse box in engine bay. Loads of damn work to get it to fit, anyhow I got it to fit just need to spend sometime lengthening parts of the harness and possibly a fuse box tuck or relocate it. The throttlebody is 4.5" so got to get new pipe and hoses

Getting the 1600cc injectors to fit the rail required buying different injector o-rings. But thanks to the lady and Advance autoparts for going through every seal kit to find o-rings the size we needed.

The transmission has not been tackled yet, just opened the box and noticed that the inspection shield on the bellhousing is broken, fedex brutalized the box, But I'll weld it saturday.

What's been done so far,
-6an dual fuel lines run all the way to a Y which is lead to a -8an 1000hp rated fuel filter.

then this is lead to a -8an Y which is then split to dual -8an fuel feed lines to either side of the Sard Fuel Rail. With -6 an return line to the Aeromotive Fuel Pressure regulator, and -6an return. All fed by dual Supra Denso Fuel Pumps (a 3rd might come onboard if i can find the triple pump holder)

I will put pics when i get a chance. still got to pull the wiring harness and delete the automatic transmission connections. etc etc

[ceelos]

pics pics pics

[Silent_NightR34]

4.5 inch throttle body? wtf? did you mean 3.5?

[scientist]

that kinda caught my attention too