quick rb20dt transmission question

[Black_label_240sx]

Can't seem to find any sources that agree on how much a rb20det transmittion can reliably handle.

any input ?

[Yellow4g63]

Carl has one behind his RB30. If you drive it like a honda kid you will prob break it lol.

[placham]

+1 ^

Should also look at KA-T.org see what people are running these days, KA has same trans as Rb20 with different bellhousing bolt pattern.
If I had to put a number think I heard ~400 is safe on them, but thats what I heard. One on my 20 runs fine, besides on a hard shift (highway pull) from 3rd to 4th you can hear synchros scream for help lol. Guess its al down to how well it maintained and taken care off.

[Carl H]

syncros wernt happy with life when i pulled it out but other than that it was just fine, just dont drive like a total tool and launch at 9krpm.

[Black_label_240sx]

ok, thats comforting to here- another quick questions as I don't want to put another thread up for it- but rb20 crank ? what rpms is it solid to, no went will it go bang, but a healthy rpm for it to visit, assuming the rest of the motor can take it and.
person opinions on building a rb20, don't see alot of people doing it, but seems like a really fun motor to me, couple of other people have 25s here and I can't really feel a difference in power with them.

[Yellow4g63]

it's just like the other RB motors. too much rpm and you will kill the pump, or it will just slip on the collar. Older RB engines have a narrow drive vs the newer RB's. If your going to build it stroke it and make it a RB24. It's expensive to do that's why most people just buy another motor. btw did you ever get a start up file for your AEM s2?

[Carl H]

unless you have the means to make power at high rpms, its not worth it to spin past 6800 on a 20.

cams/springs/headwork/collared crank/upgraded oil pump? spin that biatch to 8500.

[Black_label_240sx]

it's just like the other RB motors. too much rpm and you will kill the pump, or it will just slip on the collar. Older RB engines have a narrow drive vs the newer RB's. If your going to build it stroke it and make it a RB24. It's expensive to do that's why most people just buy another motor. btw did you ever get a start up file for your AEM s2?

for the rb24, all I saw was the tomei 2.2 pistons, do you use the rb26 connecting rods/crank ?
i noticed the pistons are 82 m m( from tomei ) and the stock bore is 78 mm - wouldn't that make the block walls really thin and more easily cracked ?

for the aem 2 - I called up aem and after talking to 2 of their techs finally got it out of them that the 25/26 base cals work for startup. We just tuned it from there.

[Black_label_240sx]

unless you have the means to make power at high rpms, its not worth it to spin past 6800 on a 20.

cams/springs/headwork/collared crank/upgraded oil pump? spin that biatch to 8500.

Ya i plan on porting the head for more flow. maybe over sized valves with cams/ n1 oil pump.. not gonna lose another rb to pump failure

Collared crank, elaborate please?

thanks !!

[Yellow4g63]

it's just like the other RB motors. too much rpm and you will kill the pump, or it will just slip on the collar. Older RB engines have a narrow drive vs the newer RB's. If your going to build it stroke it and make it a RB24. It's expensive to do that's why most people just buy another motor. btw did you ever get a start up file for your AEM s2?

for the rb24, all I saw was the tomei 2.2 pistons, do you use the rb26 connecting rods/crank ?
i noticed the pistons are 82 m m( from tomei ) and the stock bore is 78 mm - wouldn't that make the block walls really thin and more easily cracked ?

for the aem 2 - I called up aem and after talking to 2 of their techs finally got it out of them that the 25/26 base cals work for startup. We just tuned it from there.

CP has pistons for the RB20 already for 81mm. Search Freshalloy forum in the 240sx advanced section. There is a RB24 build thread in there, I can't remember his name but his motor is already built. He used 26 rods, crank and cp 81mm pistons.

[Black_label_240sx]

will do thanks ! - but about the cylander walls, won't that make them more brittle ?

[Yellow4g63]

Can't really say since I never did one lol. I think that's why he only went 81mm vs 82.

[Black_label_240sx]

its annoying that cp is the only one who really makes pistons for the rb, in your opinion are they decent ?

[Yellow4g63]

Haven't heard anything bad about them. I bought some for my SR20VET build as well with the upgraded wrist pins.

[Black_label_240sx]

Haven't heard anything bad about them. I bought some for my SR20VET build as well with the upgraded wrist pins.

so..shiny

the rb26 crank is a direct bolt to the rb20 block ?

[Yellow4g63]

You will need to do a line bore for the new crank but works. I just looked at his build thread he used JE pistons.