Jump to content
SAU Community

Recommended Posts

R32 RB20DET
Gear Ratios
1st - 3.321
2nd - 1.902
3rd - 1.308
4th - 1.000
5th - 0.759
Reverse - 3.636
Final - 4.300

RB25DET
Gear Ratios
1st - 3.214
2nd - 1.925
3rd - 1.302
4th - 1.000
5th - 0.752
Reverse - 3.369
Final - 4.363

Z32 300ZX
Gear Ratios
1st : 3.214:1
2nd : 1.925:1
3rd : 1.302:1
4th : 1.000:1
5th : 0.752:1
Final Drive : 3.692
Reverse : 3.369:1

Z31 300ZX
1st : 3.324
2nd : 2.077
3rd : 1.360
4th : 1.000
5th : 0.751

VL Turbo
Gear Ratios
1st: 3.580:1
2nd: 2.077:1
3rd: 1.360:1
4th: 1.000:1
5th: 0.760:1
reverse: 3.636:1

RB25DET gear ratio's are hard to come by, I found these on SAU some time back.

Strange enough they are the same as a reliable Z32 300ZX source.

Is any one able to confirm the RB25DET gearbox ratios?

For those that want to fiddle...

http://racingdownloads.com/racing_software-22.html

R32 RB20DET Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2777 (to 3723)		  -2991 (to 4009)
 2 -> 3		 -2030 (to 4470)		  -2186 (to 4814)
 3 -> 4		 -1531 (to 4969)		  -1648 (to 5352)
 4 -> 5		 -1566 (to 4934)		  -1687 (to 5313)

RB25DET Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2607 (to 3893)		  -2807 (to 4193)
 2 -> 3		 -2104 (to 4396)		  -2265 (to 4735)
 3 -> 4		 -1508 (to 4992)		  -1624 (to 5376)
 4 -> 5		 -1612 (to 4888)		  -1736 (to 5264)

VLT Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2729 (to 3771)		  -2939 (to 4061)
 2 -> 3		 -2244 (to 4256)		  -2416 (to 4584)
 3 -> 4		 -1721 (to 4779)		  -1853 (to 5147)
 4 -> 5		 -1560 (to 4940)		  -1680 (to 5320)

Z31 Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2438 (to 4062)		  -2626 (to 4374)
 2 -> 3		 -2244 (to 4256)		  -2416 (to 4584)
 3 -> 4		 -1721 (to 4779)		  -1853 (to 5147)
 4 -> 5		 -1560 (to 4940)		  -1680 (to 5320)

For those that are interested I've made a dyno spool comparison of the mine, sky30's and Ash's.

The reason mine jumps up sharply is it basically spools up instantly at that rpm, if shaun had loaded the car up at a lower rpm ~1500rpm it would have been a slightly better indicator of how it spools in the real early rpm.

I haven't attached bl4ck32's 218rwkw run as he doesn't have a print out. :)

His little plain bearing MQT/Dynamic Turbochargers RB20 highflow makes 218rwkw on 16psi and it spools ever so slightly better than the vg30det turbo shown here.

I think if ash were to get an ebc on to his nice tight little actuator he may bring full spool in slightly earlier, which actually would look too bad.

Dial some more boost in and it should hold power a little better than the .82. BUT it is difficult to tell as sky30 is making a shiet load more power/airflow at that rpm so ash's power curve very well may follow sky30's rapid nose over.

I really do believe this rpm/airflow/velocity point is the limitation of the standard exhaust manifold.

Especially when you see blokes like 88sillouete or what ever his alias is running a nice exh. manifold, stock head, td06-20g and he flicks it to 7200rpm no problems.

Ash,

At 100km/h yours is making a bee's dick more power than a healthy R33 RB25DET running 13psi to make a total of 200rwkw, usual mods pfc etc.

80km/h you are down 18rwkw compared to the rb25det where as sky30 is the same..

So essentially... Sky30's RB30DET GT35r .82 will feel the same at 80km/h as an rb25det running the stock turbo at 13psi. :wub:

Impressive when you look at it like that.

60km/h... who knows, most likely they will be the same, if not the rb30det will have the upper hand as 60km/h is some where around 2000rpm.

If one was able to get the 1.06 holding power until 7000rpm I think it would be a rather drivable street car with a downlow (up to 3000-3500rpm) stock rb25det power delivery that simply becomes more and more insane as rpm's increase. I hope that makes sense if you visualise the power curve. :D

good work Joel, looking at the spool comparison makes me think something is definitely not quite right with my car!

Shaun did also say that i need more tension on the actuator as he said it seemed to be a bit loose.

Nice work Gav! Cars looking good!

R32 RB20DET Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2777 (to 3723)		  -2991 (to 4009)
 2 -> 3		 -2030 (to 4470)		  -2186 (to 4814)
 3 -> 4		 -1531 (to 4969)		  -1648 (to 5352)
 4 -> 5		 -1566 (to 4934)		  -1687 (to 5313)

RB25DET Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2607 (to 3893)		  -2807 (to 4193)
 2 -> 3		 -2104 (to 4396)		  -2265 (to 4735)
 3 -> 4		 -1508 (to 4992)		  -1624 (to 5376)
 4 -> 5		 -1612 (to 4888)		  -1736 (to 5264)

VLT Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2729 (to 3771)		  -2939 (to 4061)
 2 -> 3		 -2244 (to 4256)		  -2416 (to 4584)
 3 -> 4		 -1721 (to 4779)		  -1853 (to 5147)
 4 -> 5		 -1560 (to 4940)		  -1680 (to 5320)

Z31 Gearbox

Gear Change  RPM drop (change @6500)  RPM drop (change @7000)
-------------------------------------------------------------
 1 -> 2		 -2438 (to 4062)		  -2626 (to 4374)
 2 -> 3		 -2244 (to 4256)		  -2416 (to 4584)
 3 -> 4		 -1721 (to 4779)		  -1853 (to 5147)
 4 -> 5		 -1560 (to 4940)		  -1680 (to 5320)

Wow, the memory isn't that bad, the VLT box has the extra 213 rpm drop on the 3 --> 4 change compared to the RB25 box. In fact the VLT box has wider spacing between all gears, except 4 --> 5 which is irrelevant anyway.

:) cheers :wub:

Joel, id be very interested if you could do a similar dyno camparison on torque readings between mine, yours and ash's cars.

Ash, What RPM do you get ful boost at??

I wouldnt be too dissapointed, a mate of mine runs the 1.06 housing on his VLT and doesn't get full boost till around 4200RPM.....

Hey guys,

Just on that subject of when boost comes one at what rpm, I have a r32 GTR and I put a gt35r with a tiny .63 rear housing on it with ext gate, I was after early spool for easy street driving and a more useably torque curve. With 15 psi and 310 rwkws it comes on boost earlier than the standard twins did and holds great boost and a firm curve to 8500 rpm.

When I had decided to go for such a small housing I was warned by many modders that I would get pressure and heat problems due to the housing being to small but all it has been is an excellent street setup.

Oh yeh and thnx for the ratios guys I will most definatly be keeping my gtr diff. :D

Cheers.

p.s My mate is as we speak setting up his rb30 bottom with 34gtt head for his drfit 32gtst he also is running ext gate and a .63 housing will let you know how it goes.

Hey guys,

Just on that subject of when boost comes one at what rpm, I have a r32 GTR and I put a gt35r with a tiny .63 rear housing on it with ext gate, I was after early spool for easy street driving and a more useably torque curve. With 15 psi and 310 rwkws it comes on boost earlier than the standard twins did and holds great boost and a firm curve to 8500 rpm.

When I had decided to go for such a small housing I was warned by many modders that I would get pressure and heat problems due to the housing being to small but all it has been is an excellent street setup.

Oh yeh and thnx for the ratios guys I will most definatly be keeping my gtr diff. :D

Cheers.

p.s My mate is as we speak setting up his rb30 bottom with 34gtt head for his drfit 32gtst he also is running ext gate and a .63 housing will let you know how it goes.

Sounds good, What RPM are you making full boost at? And is the engine a RB20 or RB26??

Joel, id be very interested if you could do a similar dyno camparison on torque readings between mine, yours and ash's cars.

Ash, What RPM do you get ful boost at??

I wouldnt be too dissapointed, a mate of mine runs the 1.06 housing on his VLT and doesn't get full boost till around 4200RPM.....

i'm getting 15psi by 3900rpm, i love this motor and turbo, driving home from work last night (1:30am) was about 4degrees, i just put it into thrid from second and put my foot down and the thing just shoves you back in your seat and pulls so had to the rev limiter!

I wouldnt be too dissapointed, a mate of mine runs the 1.06 housing on his VLT and doesn't get full boost till around 4200RPM.....

Just out of curiousity why do people run such big rear a/r's surely a ~.8 would be far more suitable unless its a drag/street car.

Just out of curiousity why do people run such big rear a/r's surely a ~.8 would be far more suitable unless its a drag/street car.

When an offer presents its self that is too good to refuse (1k) and is internal gate that is basically bolt up.

Just out of curiousity why do people run such big rear a/r's surely a ~.8 would be far more suitable unless its a drag/street car.

i probably ideally wanted a .82 but at the moment you can't get a 35/40 with an internal gate (wanted this for the more stocky look) but when the 35/40 came up for sale at a really good price with the 1.06 housing i couldn't refuse and to be honest i haven't regretted it for a second, it is very streetable with the torque the Rb30 produces and i'm only going through 10L/100kms of fuel now due to not it being on boost all the time! Just need some new diff gears now so that i can use first and second a little more!

Edited by mr_rbman

Hi guys just finished my 25/30 conversion, car idles fine on cold start then once she warms up idles less them 400rpm any ideas why?? Then when driving her she stalls when i stop, at idle, i think she is running a bit too lean, i do have a pfc and a hand controller but im not sure how to change the idle, afm or injector duty cycle, should i do this or leave it to an expert? My specs are as follows r32 GTS4 rb25 non vtec head 3L rb30 bottom end, pfc, gtr fuel pump, stock afm, gt3540 turbo, tial 44 external wastegate, stock injectors and tb etc.

Edited by FOOLBOOST

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Have a look at that (shitty) pic I posted. You can see AN -4 braided line coming to a -4 to 1/8 BSPT adapter, into a 1/8 BSPT T piece. The Haltech pressure sender is screwed into the long arm of the sender and factory sender (pre your pic) into the T side. You can also see the cable tie holding the whole contraption in place. Is it better than mounting the sender direct to your engine fitting......yes because it removes that vibration as the engine revs out 50 times every lap and that factory sender is pretty big. Is it necessary for you......well I've got no idea, I just don't like something important failing twice so over-engineer it to the moon!
    • Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
×
×
  • Create New...