Transmission Options For A High Hp Rb30 Gtr

[4jo3]

Hello,

I am currently in the middle of building a high horsepower RB30. And I was told my weak point is my transmission. The motor is going in an R32 GTR but I bought an R33 transmission because of the double synchros. I was told my transmission probably won't last very long. So I was wondering what people are running for transmissions. Sorry, there are not very many RB30 motors where I come from, thus there is no experience. An help would be amazing. Only thing is, the motor isn't complete yet and I have no idea on what type of numbers it will put out.

Thanks.

[StealthX]

What turbos? What's your expect HP figure?

Whats it for? i.e. streeter, drag, circuit racer, hill climber??

What's your budget?

I'd suggest dog gears, PPG or maybe OS Giken if you have heaps of coin to spend.

[GTRNUR]

Skylinesky has a PPG equipped R34 getrag for sale as he has just bought a holinger box instead. If you want something that shifts beautifully then you cant go past this box, and combined with R32/33 diff ratios and a big power engine it would be a hoot to drive.

The other option is a OS gear set upgrade for your R33 tranny, but frankly dog engagement gear sets are a bitch to drive and arent remotely streetable.

[4jo3]

What turbos? What's your expect HP figure?

Whats it for? i.e. streeter, drag, circuit racer, hill climber??

What's your budget?

I'd suggest dog gears, PPG or maybe OS Giken if you have heaps of coin to spend.

The car will be street driven and it being set up for time attack. But I would say 50/50 street vs time attack. It might see the drag strip too. As for my budget... I really dont know yet. It wont be till the new year as I'm expecting i will have to save. Cheap, Fast, Reliable... Pick two comes to mind when I think about budget. As for the hp number maybe, you can help me out. I was told i will max out my turbos.

Engine Build.

Block: RB30

Crank: Stroked RB30

Bearings: ACL Race

Pistions: Custom Wiseco

Rods: Custom Pauter

Oil Pump: Jun

Water Pump: N1

Cams: HKS 280 step 2 with adjustable Greddy Gears

Lifters: Tomei

Valve Guides: Custom

Valves +1mm Exhaust, +1mm Intake Brian Crower

Springs: Brian Crower

Timing Components: Gates and Nissan

Intake Plenum: Greddy

Turbos:Twin Garrett 2860-5s with all SS lines.

Manifolds: HPI

Dump Pipes: HKS

Exhaust: Custom Twin 3" tubing into single 4" tubing with a Resonator and 5" muffler. Also Two 3" V-band cats that will be dropped out when at the track

Front Diff: Nismo 1.5way

Oil Pan: Custom

Hot and Cold Turbo Piping: HKS expect before the plenum which is a 4" custom pie cut pipe with a Greddy Type R BOV. Blitz filters

Engine and Transmission Mounts: Nismo

The head has been ported and polished and 3 angle valve seat cut, I don't have the flow bench numbers right now but I might be able to get them in a week or so. And all the usual work with the oiling system was done. ie restrictor

I'm sure I am forgetting something.

[StealthX]

Well there's about 350hp per turbo, so assuming everything's equal, you should see about 360-430kw if you are "maxing out the turbos"

If it sees the street, then (like GTRNUR said), dog engagement gears are definitely NOT your friend lol

PPG gearset or Hollinger if you have the coin (by the sound of the engine build, and knowing its a time attack car, I'd say you do )

[4jo3]

Well there's about 350hp per turbo, so assuming everything's equal, you should see about 360-430kw if you are "maxing out the turbos"

If it sees the street, then (like GTRNUR said), dog engagement gears are definitely NOT your friend lol

PPG gearset or Hollinger if you have the coin (by the sound of the engine build, and knowing its a time attack car, I'd say you do )

I like the idea of dog gears. But there is only one problem no one knows how much they are to rebuild. I would like an approximate cost... I just don't feel like dropping a ton of money on a rebuild every 6000-1000kms. (would it cost half of the price of the gearbox every rebuild?) As far as I know liberty gears makes a transmission that will hold but its not on their website. I have been talking to them and it would be a snchro transmission that would hold over 1500hp. This right now seems like the way to go but. I really like the idea of dog gears. But the liberty transmission is basically maintenance free compared to the dog gears.

[StealthX]

Dog gears + street driving = massive PITA.

I've driven a track S15 around the pits (not quite the street, but close) and it was a cvnt. Need to literally smash every gear, and its stupidly notchy at low speeds, of course on the track it amazing, but anything else, its a pain.

That liberty brand sounds like a good option! if its a synchro box then it'll be fine for the street and knowing its rated at almost triple the power you will be making, you'll be able to smash every gear with confidence. Sounds like a no brainer to me!

[T04GTR]

link on the liberty?

i know jerico or it might be liberty do a full on drag box, but i didnt notice the synchro one..

[4jo3]

link on the liberty?

i know jerico or it might be liberty do a full on drag box, but i didnt notice the synchro one..

Ya its not on the website and its special order. You have to call them.

[GTRNUR]

What exactly is the power figure you have in mind for the engine?

Because your engines cylinder head says 900+hp and your turbo's say 500... ie. your engine setup is quite miss-matched. You would be better off with a set of 260 cams and 10mm lift. Take advantage of the fact you dont have to rev the RB30 because it makes usable torque low in the rev range.

[4jo3]

What exactly is the power figure you have in mind for the engine?

Because your engines cylinder head says 900+hp and your turbo's say 500... ie. your engine setup is quite miss-matched. You would be better off with a set of 260 cams and 10mm lift. Take advantage of the fact you dont have to rev the RB30 because it makes usable torque low in the rev range.

Also my turbos have a bit of work done to them. Garrett says 360hp a side which is 720. Hopefully.

I eventually want to run big top mount twins or a single t62r or equivalent. I got the cams for a great deal. I'm hoping to put down at least 600awhp for now ... I know my motor will fall off at top end... the motor will spin to 9500rpm safely but it wont make power at high revs respectively. Basically, what happened was I finally got my rb26 up and running with the current turbo setup after a year and I broke an intake valveguide around 5000rpm after being on the road for 3 days. It scored the bore and I have always wanted to do a RB30/26 conversion as I was looking into it before this happened. So, basically my conversion was fast tracked because I didn't feel like building 2 motors. Right now I figure I will break transmissions with the turbo setup I want. I would like to work out all the kinks before I put huge power into it (transmission/clutch, intercooler and fuel) Plus, right now I don't have the funds for the current turbo setup. Also, right now I will need to buy an intercooler as well. I dunno if my clutch will hold for that long too but it is new. Its an os giken twin plate, damped with the big discs. I was just thinking of running a conservative tune as I want to do a fuel system as well. I am currently running a nismo and a stock gtr fuel pump. So I figured I would run the current turbo setup for break-in until I can build everything else bulletproof to handle 1000+awhp.

I dont know if that makes any sense. But also being a time attack car it should have a very good power band which means i dont have to rev that high. Therefore, I shud be able to short shift it, all the time and still have power anywhere. But i dunno... trying something new so maybe it will work maybe it wont.

[T04GTR]

nothing wrong with big cams. just need to play with the timing to move it all around. it has been proven a few times to get low end gains from larger cams. once the turbo is boosting all normal cam concepts go out the window.

[GTRNUR]

For power yes I agree with you, but for a street car that might be driven in traffic I dont.

Have you ever experienced driving a big duration cammed car in stop-go traffic and noticed the effect the piss poor low speed vacuum has on the effectiveness of your brake and clutch boosters? Not to mention how it effects the ability to get a good low speed tune, especialy if its a map based load sensing ecu. But even MAF ecu's dont deal too well with turbulance at low speeds caused by big cammed engines.

The 280 degree cams push the peak torque up to around 7000 rpm, so driving on a track around the torque band from 6-9000 rpm with turbo's that run out of flow on an RB30 at around 7000. Its just not going to go all that well. You'd be much better off swapping the big duration cams for some 260's or a 260/272 pair. By all means max out the lift to the limit (the 3lt will love that), but maintaining low end drivability is something I consider a must for a car that sees regular street duties.

Just my 2c..

[T04GTR]

noted.

peak torque at 7k? where did you get that figure from?

the engine in question was paul, dirt gararge.. went from 260's to 288 jun and made low rpm torque gains.. i do see with the brakes etc etc. tuning wise, should be fuel of the tps, just like na with map for ignition and fuel once at zero or near to it. pretty standard gtr tuning concept..

[rockabilly]

on subject, i had my std 33gtr box gears cryo treated, thats 1-5, input and layshaft, it rubbles at idle like a getrag when hot, but has held 550lbs @ all 4 for 3000miles now, been to the nurburgring/zolder and spa and it loves it, once driving all is quite just noisy on idle.. worth thinking about.bernie uk

[two_evil]

If your going to make big power you need a straight cut dog box like a ppg. If you want to take it easy you could get away with a os giken syncro box. Basically syncro's can't handle big power or torque for that matter.

i broke my os giken box and was only running 550hp at the wheels.

[GTRNUR]

on subject, i had my std 33gtr box gears cryo treated, thats 1-5, input and layshaft, it rubbles at idle like a getrag when hot, but has held 550lbs @ all 4 for 3000miles now, been to the nurburgring/zolder and spa and it loves it, once driving all is quite just noisy on idle.. worth thinking about.bernie uk

If your going to make big power you need a straight cut dog box like a ppg. If you want to take it easy you could get away with a os giken syncro box. Basically syncro's can't handle big power or torque for that matter.

I broke my os giken box and was only running 550hp at the wheels.

Two very different, and opposite opinions.

And I think it comes down entirely to driver style. I'll bet that Bernie treats his car firmly but nicely, and respects the fact that it is a powerful beast capable of chewing up and swallowing parts of its driveline with ease.

I'll also bet that "two_evial" drives like a mate of mine used to punish his GTR, that was till he broke it. Sideways all the time, regularly at 8000 rpm, and doing the big launches at that RPM as well. Nothing is indestructable. You can break anything if you treat it poorly enough.

Edited September 18, 2010 by GTRNUR

[two_evil]

Two very different, and opposite opinions.

And I think it comes down entirely to driver style. I'll bet that Bernie treats his car firmly but nicely, and respects the fact that it is a powerful beast capable of chewing up and swallowing parts of its driveline with ease.

I'll also bet that "two_evial" drives like a mate of mine used to punish his GTR, that was till he broke it. Sideways all the time, regularly at 8000 rpm, and doing the big launches at that RPM as well. Nothing is indestructable. You can break anything if you treat it poorly enough.

The funny thing is never launched the car hard. I was just doing a quick upshift from 2nd to 3rd and then rattle rattle all over. Its all in the torque. maybe the npc twin plate thats un sprung didn't help!

[-_-StRyDeR-_-]

anyone got a link or price on those liberty box's??

[KiwiRS4T]

anyone got a link or price on those liberty box's??

http://www.libertysgears.com/rb25-26.htm