Serious N/a Rb Power For A S13...

[benny_b]

hello from the usa.. i have a s13 hatch shell hanging around my shop that i want to go of the deep end with.. i am thinking rb20de or rb25de... i want to stay na as i have yet to see an na rb in the states.. i have looked through these forums and skylinesdownunder and see some interesting results.. just looking for some suggestions on starting point.. 20 or 25?

i am talking crazy like individual throttle bodies, header (extractors?), managment..

discuss...

benny

[342Four]

u dont get the 3 litre donk there in teh us of a do u?

bummer u

well

i would go with rb25de - not that much heavier than rb20, plus more power and torque (a bigger torque increase as bore size is the same - its only the stroke that adds more displacement)

indiividual throttle bodies would require custom fabrication i assume as i dont think anybody manufactures them for the rb25 (i think they r around for the rb26 tho)

exhaust side go some decent extractors and around a 2.5 inch exhaust

get some cams put in if u want - there are nismo manufactured cams for the rb25

management - use the standard ecu for 'run in' if u do any internal work (this includes head work) then u cant go past Apex'i SAFCII (cant think of any others of teh top of my head - somebody help)

just my info

[BADR33]

its a shame you dont get rb30s over there. i have one here and its awesome.

i would do rb25 if thats what you can get.

but what would be better is to get rb26 and run it NA, run high compression 6 throttles.. damn that would sound so nice and be bloody fast

[StockyMcStock]

i would go with rb25de - not that much heavier than rb20, plus more power and torque (a bigger torque increase as bore size is the same - its only the stroke that adds more displacement)

funny, i could have sworn the 20 and 25 had different bore sizes. last time i checked they did anyway.

as BADR33 said, go straight to the 26. rebuild it as a higher-comp motor up around 10.5:1 and make some nice headers for it. it will be the cheapest and best way to do what you want.

p.s. there's a reason you don't see many n/a RB's around.....

[88silhouette]

go with an rb30

you will never look back

the extra money is worth it

happy to send one over to you if you want. pm me

[342Four]

hmmm maybe the rb20 has a diff bore - but not by much then

[Maxx]

as BADR33 said, go straight to the 26. rebuild it as a higher-comp motor up around 10.5:1 and make some nice headers for it. it will be the cheapest and best way to do what you want.

if there is a rebuild, 10.5:1 is WAY too low, more like 12.5:1 or higher

[benny_b]

thanks for the replies... i know there is a reason you don't see many n/a rb's.. and i like a challange.. what are you guys rev'ing your rb30's too?

i am thinking i'd like to rev to 10k even.. and i'd like to make in the 200-250-225 kW range (around 300rwhp)..

i am leaning the way of starting with a 26.. so i start with hex throttles.. and i'm pretty sure getting it to rev to 10k wouldn't be too much of a stretch.. but it only has low compression.. i can buy a n/a rb25 and not have to open the motor..

benny

[Eug]

you will have to open the motor anyway to build something that will rev to 10k...

rb30s are apparently known to have harmonic balancer issues in the high rev range, so you may want to look into something there

ideally i believe the best NA RB combination would be an RB26 head with individual throttle bodies and trumpets, donked onto an RB30 block and with those light weight hypereutertic (sp?) pistons and like Maxx said 12.1:1 compression or even 13, depending on how much money your willing to pour in and the quality of your fuel...

[Maxx]

thanks for the replies... i know there is a reason you don't see many n/a rb's.. and i like a challange.. what are you guys rev'ing your rb30's too?

i am thinking i'd like to rev to 10k even.. and i'd like to make in the 200-250-225 kW range (around 300rwhp)..

i am leaning the way of starting with a 26.. so i start with hex throttles.. and i'm pretty sure getting it to rev to 10k wouldn't be too much of a stretch.. but it only has low compression.. i can buy a n/a rb25 and not have to open the motor..

benny

i can't see how can u rev a rb25 or even rb26 to 10k without opening the motor

more like 7k of rb25 and 8.5k for rb26

and the stock 10:1 and 8.5:1 compression will only give u around 200hp, that's at flywheel

either of them u will need a highly balanced, blue printed bottomend for the high rev, with custom forged pistion to bring the compression up.

u will also need some cams to make sure the engine will make power up to the built redline

plus hd valve spring + more

even with such a motor, i still doubt it can pull low 200rwkw

might need to throw in some giggling gas too to reach yr aim

[benny_b]

so 10k is asking too much of a stock motor..? i wasn't thinking so based on 9k being on factory tachs and nismo versions for gtr's having 10k.. i know just because the number is there doesn't mean the motor will go that high.. but i would think it could get close.. i know of a couple "project" gtr's over here that i know rev to 9.5k with out having opened the motor and those cars are all still seeing boost..

[Maxx]

even u forget about reliability of the motor and rev to 10k, u still won't make the power u want, not even close

[BADR33]

if you want high revs go rb26 and ballance the internals, light flywheel and billet crank pully.

my rb30 has been ballanced and revs smoothly up to rev limiter at about 7200rpm.

yeah rb26 head on rb30 bottom end would be awesome as the rb30 has very good torque all the way through. have a look at my dyno results for mine. thats with rb25 head.

whatever the redline is on gtr then you can rev it to that then. but its all at a risk. if i was to do that i would want an r33 gtr motor and run N1 oil pumps and stuff.

for your power aim its not gona be cheep. you will need lumpy cams. ported and poilishd head. custom high compressoin pistons mb.

in the end its up to you. none of this has really been done as people just decide that they want max power so they go boosted.