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Rb30 Vs Rb25


R34NRG
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3.0L VS 2.5L  

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point taken keymaker, i guess i just wanted to know why on earth anyone would choose the rb25. and the quotes were mainly from ns.com and it was argued over there until a fellow SAUer wanted me to try my luck on a skyline forum...(yeh i dunno wat he was thinkin)

if your forging a rb25 it dosnt cost much to convert to 3.0L, so lil i dont even think its worth mentioning, so unfortunately i cant take that as a valid reason for choosing a rb25.

but your right, it is a public forum and some people prefer gorrilas then woman.

There's your problem. They're all SR and CA lovers over there. What would the majority of them know about an RB. And vise versa of course

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hahaha ok. The point IOWNU was trying to make was, it is rediculous to think a RB30 is automatically going to be better than a "certain" RB25. Its true what he says. Just because someone has an RB30det, it doesn't mean its not going to be beaten by a RB25det. As I said, its not the be all and end all.

You've got to get yourself out of the narrow minded rut your in. Have appreciation for all motors.

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well if thats wat he meant that i retract my idiotic performance.

i never said the rb30 is a be all end all. all i said was i know why i went rb30. and everyone was like wtf why rb30. rb25 is way better.

yes i agree that certain rb25s could proberly munch a rb30 but wats the point in comparing apples and oranges. i was clearly explaining why a rb30 would be the ideal pick over a 2.5. not in personalized scenarios.

If I could spend money again (And enough of it) I'd probably have a 6L V8 residing in my bay with a super charger on it personally...

defiently, although i still may stick turbos on the big V =D

or a v12 lol

Edited by R34NRG
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well if thats wat he meant that i retract my idiotic performance.

i never said the rb30 is a be all end all. all i said was i know why i went rb30. and everyone was like wtf why rb30. rb25 is way better.

yes i agree that certain rb25s could proberly munch a rb30 but wats the point in comparing apples and oranges. i was clearly explaining why a rb30 would be the ideal pick over a 2.5. not in personalized scenarios.

I know you never said it is the be all and end all. But the way you come across to them is that it is to you. You know why you went RB30, you know of the benefits, don't worry about what they say.

You have to remember also, RB30's start off with a SOHC. By you dropping a RB25 or 26 head on instantly customizes your motor. After that its all customized motor vs customized motor arguements, and thats what they've given you.

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If I could spend money again (And enough of it) I'd probably have a 6L V8 residing in my bay with a super charger on it personally...

Thats my plan . . . . . if i can ever kill this 25 off . . . . . .

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it seems to have got you a bit upset but look at the title... RB30 vs RB25 vs RB26... this will always start opinion slinging

if you like as it seems to mean a LOT to you, to end all conjecture i will give you free time on the dyno so you can compare apples to apples, you can then end prove to all the nay sayers that it is superior i have plenty of RB30, RB25 and RB26 combinations on there you can overlay then post up...

come down with andrew, red 180 went thrashing with you the other night.... he has some JBs here that need drinking :D

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Alot of people ask me why i did not go down the 3L bottom end path with all the money i have spent on my built 25 motor.

And the simple reason is because of preference. Anyone can make torque and power with a 3L. Just strap a big turbo on it and away you go.

I wanted to build the most efficient 25 i could.

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Alot of people ask me why i did not go down the 3L bottom end path with all the money i have spent on my built 25 motor.

And the simple reason is because of preference. Anyone can make torque and power with a 3L. Just strap a big turbo on it and away you go.

Yep thats basically it for me, I am still umming and ahhing about what I want to do with mine. In terms of outright performance, a 3litre is it - end of story. There is no replacement for displacement, and given that you use the same head as the 2.5 or 2.6 you are at no loss. The 3litre has the nearest to perfect rod/stroke ratio out of the bunch if I remember rightly and there is no reason without balancing and a decent strength bottom end, and a decent head that they shouldn't be able to rev HARD. I know people spinning them to well over 8000rpm, and making really really good power with them.

Hell there was an R34 GTR built here in NZ with a forged RB30 bottom end which runs >1000hp and up to around 8500rpm - probably has the widest/fattest power delivery out of any street Skyline I have seen. I like the idea of having something like that but on the flipside SOOO many people have RB30DETs, and in NZ at least there is no love for the 25s so it'd be nice just to build an RB25 and have and enjoy a powerful streetable one which you KNOW is good. If nothing else, for the sake of staying pure to what the car was is a good reason to stick with the RB25.

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its in english at the top ash.

i want to hear evryones points and views between the 3.0L and the 2.5L

im waiting on all these 2.5 ppl to post why they would choose it. and i havnt heard anything yet.

so i havnt actually been able to not accept points or views.

why u always breakn my ballz ash? i could point u to at least 5 topics straight up right now that you could close. "what alarm clock wouuld u be" "worlds hardest game....like wtf?"

i must admit though i was challanged by another SAU member to create this thread because he honestly believed 2.5s are superior to 3.0Ls and im still waiting for him to show.

and yes i know im actn a lil childish but u cant blame me wen i got ppl telln me to stfu and that i dont no wat im talkn about

1. Your posting in the RB30 conversions section, do you honestly think people with RB25's are going to look in here?

2. You dont need 15yr old driven posts in big red, silly wording and so on. People here are not 15, and this isnt myspace. People here do not find it amusing.

Im not breaking your balls, your just wasting everyones time with half the threads you create.

Think before typing.

Personally, unless i was chasing 400rwkw+, RB25 all the way.

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it seems to have got you a bit upset but look at the title... RB30 vs RB25 vs RB26... this will always start opinion slinging

if you like as it seems to mean a LOT to you, to end all conjecture i will give you free time on the dyno so you can compare apples to apples, you can then end prove to all the nay sayers that it is superior i have plenty of RB30, RB25 and RB26 combinations on there you can overlay then post up...

come down with andrew, red 180 went thrashing with you the other night.... he has some JBs here that need drinking :P

trent is it?

i dont no if it was you who i spoke to on the phone about fitting a D jetro into the car. was plannin to bring the car around the other day but havnt had the chance. you free tm? ill bring my graphs....i cant seem to find em atm

you free tm? ill pop down

thanks for the dyno offer buddy ill take you up on it, but let me buy u a slab. VB good?

1. Your posting in the RB30 conversions section, do you honestly think people with RB25's are going to look in here?

2. You dont need 15yr old driven posts in big red, silly wording and so on. People here are not 15, and this isnt myspace. People here do not find it amusing.

Im not breaking your balls, your just wasting everyones time with half the threads you create.

Think before typing.

Personally, unless i was chasing 400rwkw+, RB25 all the way.

we all know ash if i made it anywhere else youd proberly remove it or move it here.....lol

but alright alright i get your point, i did kinda go overboard with the big writing, i just wanted to make the point as clear as possible.

i think 400kw is a bit high even for the rb25......if you want lag be my guest.......id recommend going 3L from 300-350+ honestly

youd have to be running t04 or even bigger to hit 400 on a rb25.....youll defiently have to forge.......which would cost you the same going 3.0L.

if its personal taste that you want a decked out rb25. then thats fine.

im glad i went 3.0L

Edited by R34NRG
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i think 400kw is a bit high even for the rb25......if you want lag be my guest.......id recommend going 3L from 300-350+ honestly

youd have to be running t04 or even bigger to hit 400 on a rb25.....youll defiently have to forge.......which would cost you the same going 3.0L.

Have you ever been in/driven an R33 with that kind of power or its just a conclusion?? I have been in a 400kw R33 GTS25t running a .82a/r GT3582R and it was really quite streetable, it didn't have V8 style urgent below 3500rpm but it wasn't a gets-beaten-by-Fiestas-from-lights type car by any stretch either. If you stayed heavy on the gas over 3500rpm in 1st/2nd/3rd gear it would not take long at all for the tires to get completely baked, surely the only difference with a RB30 would be a couple tenths of a second earlier before the tires start baking?

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Have you ever been in/driven an R33 with that kind of power or its just a conclusion?? I have been in a 400kw R33 GTS25t running a .82a/r GT3582R and it was really quite streetable, it didn't have V8 style urgent below 3500rpm but it wasn't a gets-beaten-by-Fiestas-from-lights type car by any stretch either. If you stayed heavy on the gas over 3500rpm in 1st/2nd/3rd gear it would not take long at all for the tires to get completely baked, surely the only difference with a RB30 would be a couple tenths of a second earlier before the tires start baking?

yes i have (scroll up and read 4th post buddy), and honestly it is laggy, when you compare it to 3.0L. i mean when your launching at 4k its great, you keep the boost up and it should do its work. but in other cases its a no show. and it sounds like you havnt been in a 3.0L

i make 20psi by ~3800 budddy. ask your mate how much psi he must be running to hit 400. and ask him when it does hit full boost. trust me....theres alot more then a couple tenths of a second

torque rules the street

Edited by R34NRG
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Hell there was an R34 GTR built here in NZ with a forged RB30 bottom end which runs >1000hp and up to around 8500rpm - probably has the widest/fattest power delivery out of any street Skyline I have seen. I like the idea of having something like that but on the flipside SOOO many people have RB30DETs, and in NZ at least there is no love for the 25s so it'd be nice just to build an RB25 and have and enjoy a powerful streetable one which you KNOW is good. If nothing else, for the sake of staying pure to what the car was is a good reason to stick with the RB25.

Is that the RIPS one? RIPS PWNSALL!!! Im not bias or anything....

Personally I love RB's they are all great motors

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1. Your posting in the RB30 conversions section, do you honestly think people with RB25's are going to look in here?

ummmmm... :P

Personally, unless i was chasing 400rwkw+, RB25 all the way.

What if you want both?

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yes i have (scroll up and read 4th post buddy), and honestly it is laggy, when you compare it to 3.0L. i mean when your launching at 4k its great, you keep the boost up and it should do its work. but in other cases its a no show. and it sounds like you havnt been in a 3.0L

i make 20psi by ~3800 budddy. ask your mate how much psi he must be running to hit 400. and ask him when it does hit full boost. trust me....theres alot more then a couple tenths of a second

Yes I have been in a few RB30 powered cars actually, one of which is a proven 10s car and another one (given its 130mph trap speeds) is only a matter of time before it does a ten.

Can you explain what "all other cases" means?? All motorsport in a Skyline should be done above 4000rpm, and the R33 I refer to had plenty below 4000rpm to not feel compromised at all for normal street duties - it reaches full boost (22psi) by 4300rpm. Its a proven full interior 10s car and runs on pump gas. The RB30s were reaching their peak power at low 6000rpm while the RB25 I refer to at well over 7000rpm and actually on the road felt angrier/faster overall than the RB30s I've been in. Virtually all the RB30DETs I've been in are your typical stock RB25 head, stock RB30 bottom end, 22psi type setups. The 10s RB25 has a REALLLY solid push in the back from just over 4000rpm carrying through to 8000rpm as opposed to just under 4000rpm to 7000rpm for the RB30DETs.

Bare in mind I have already said the RB30DET is in my opinion the better motor, I am just sticking up for the RB25DET in the light that people are possibly selling them a little short.

The RIPS car I was talking about was the blue one, not the black one - http://drag-r.com/gallery5.htm

Edited by Lithium
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Yes I have been in a few RB30 powered cars actually, one of which is a proven 10s car and another one (given its 130mph trap speeds) is only a matter of time before it does a ten. Can you explain what "all other cases" means?? All motorsport in a Skyline should be done above 4000rpm, and the R33 I refer to had plenty below 4000rpm to not feel compromised at all for normal street duties - it reaches full boost (22psi) by 4300rpm. Its a proven full interior 10s car and runs on pump gasThe RB30s were reaching their peak power at low 6000rpm, the RB25 I refer to at well over 7000rpm (big cams) and actually on the road felt angrier/faster overall than the RB30s I've been in so far, which two of are your typical stock RB25DE head running .82a/r GT3582R on 22psi. The RB25 has a REALLLY solid push in the back from just over 4000rpm carrying through to 8000rpm as opposed to just under 4000rpm to 7000rpm.

Bare in mind I have already said the RB30DET is in my opinion the better motor, I am just sticking up for the RB25DET in the light that people are possibly selling them a little short.

The RIPS car I was talking about was the blue one, not the black one - http://drag-r.com/gallery5.htm

So stock heads and running in the tens? What sort of power do they make

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So stock heads and running in the tens? What sort of power do they make

Both in the territory of 360-370wkw on Dynapack hub dynos on just pump gas. The one running 130mph which hasn't done a ten yet is in an R32 GTSt running a .82a/r GT3582R, the one which HAS done a ten was in a GTS4 and had a small shot of nitrous to help it along additional to the ~370kw it ran on 22psi through a Turbonetics T66. It did 11.1 without nitrous.

Funnily enough there is an RB25DET powered R32 GTSt here in NZ running only forged pistons, completely stock head but a shot of NOS and a GT3582R which has done several flat tens. So far the stock head RB25DETs here are faster than the stock RB25 head RB30DETs here, maybe due to not having a slightly compressed rev range?

Edited by Lithium
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Whats with the rev argument? I've never heard anyone bagging out the 2JZ calling it a truck engine & not good for reving. :(

(and we are talking built for turbo, not ppl using RB30E stock bottom ends)

Note: bore/stroke of RB30 is 86x85mm, 2JZ is 86x86mm

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