question for RB GURU"S

[twotonedrift]

hey guys, i have a simple simple question for all you rb enthusiest's.... i am torn between keeping my rb20 or selling it to try and get an sr20... reason being is because i want to rebuild a motor to withstand at least 550hp..and i know that you can easily ring power out of an sr cheaper.....IS it POSSIBLE to safley build an rb20 to make that kind of power... i NEED ADVICE . thanx guys...

[Cjmartz2k]

sell

[danielmcn]

YES. It will cost more to do it with an rb20, but considering you have the whole swap already all money spent wil go into power. If you sell to go sr, your only going to get 1200 at best for the swap. And thats on a good day, I paid 600 for one with mounts. The resale value on rb20s is low.

http://www.youtube.com/watch?v=-9GswiaG ... re=related
that is/was a member of nico. That thing has a stock block and made 398. So yes you can hit 500 whp with a built rb20det.

[TimTurboZ]

I like my RB20 better than SR's I've rode in just sayin...but SR's have more parts readily available and on CL

[danielmcn]

I have owned both. I just got rid of my s13 blacktop to go back to an rb20. The sr just didnt have enough balls for me.....

[DustinZ]

Rb25det for the win. sr and rb20 have crappy transmissions and the but loads of money you would spend forging either definately pays the extra cost for a rb25. A good setup on a rb25 with just a head gasket and studs on stock internals would net you the power figure you want with a big fat power band. SR=suck!

DustinZ

[Cjmartz2k]

http://www.skylinesaustralia.com/forums ... e__st__220

Now keep in mind I didn't got through EVERY page of this thread, but of the 6-7 I did, the best results I found were two guys at a little over 400rwhp with a GT35r on fully built RB20's running e85. If you want to try and get 500rwhp out of one, you have your work cut out for you. I'm not saying it can't be done, but I am saying it's not worth the time/money to get an RB20 to do it.

[Cjmartz2k]

Hold the phone. Just found 492rwhp..........................

on a RB24 stroker with a TO4z. I don't know how familiar you are with turbo's, but that turbo ain't small. Like I said, it can be done, but you'll have to spend stupid money to turn your RB20 into a laggy drag strip only motor. 350-400rwhp seems to be about the limit of usable, streetable power out of them.

[twotonedrift]

Thanx guys, i appreciate the advice...thats what i was pretty much looking for.. and what i expected.. my decision is still hard to make. . im not to worried about the weak transmissions rb20s have. but i am now convinced that an sr would be the way to go in order to ring at least 500 ponies. . i was already half way expecting that it was gonna take ridiculous money to make a rb20 push that power. .but ive always favored the rb series over an sr any day.. theres many more write ups and parts for an sr build correct? i dont wanna be one of the few to try and push and rb20s limits like that.lol... once again, thanx...

[b00stinbmx]

why not just sell the rb20 and get a rb25? that was the smartest thing i EVER did. i sold my rb20 for 1200 and went and bought a rb25 swap for 1750. sat on it for awhile collected parts and then drove it for a year on stock turbo and made 290whp at 12psi. last winter i did arp head studs and a new oem HG with a topmount gt35r set up and im making over 400whp. i think you should strongly consider this plan instead. im on stock motor and i think if i keep it at 1bar its going to hold just fine, its already taken a drift event and plenty of street beatings. i think you would be alot happier in the long run doing it right if your power goals truly are what they say they are. you aren;t going to get it on a rb20 and its stupid to just build it, if you already had the SR id say go for it but you will end up spending more money and have a lower torque set up and a weaker transmission. im speaking from personal experience and i;ve experienced first hand quite a few different set ups in 240s, built srs, ka-t, 2jz, rb25s 20s etc etc. go rb25

[Krazykouki]

I've built quite a few RB's and SR's...driven them around, tracked them, etc..etc..

RB > SR

It will cost you almost the same amount to get 500 out of an SR and a 500hp SR will still be inferior. DO not get an RB25 unless you are prepared to build it, I f*** hate my RB25 and I am going to swap it for a 26 to make myself happy. I miss my old RB20, I beat the s*** out of that motor and it never let me down, even with 400+. I beat that car for 2 hours straight every Saturday night and daily drove it all week just to do it all over again.

If you go with an SR you will end up with an RB in the end no matter if it is an RB20, 25 or 26...don't hate on one because its the runt of the litter as the runt can turn out to be just as big and bad as the rest of its brothers.

[Cjmartz2k]

I'm not trying to sound like a d!ck Krazykouki, but I couldn't disagree with you more. No way in hell it would be half as cheap to make a RB20 make the same power (500hp) a SR would. Also, you don't like your RB25, especially compared to your RB20? That just baffles me.

[twotonedrift]

i never really thought to do a rb25. arent they ALOT heavier though??? also, why do you hate your 25?

[Krazykouki]

I'm not trying to sound like a d*** Krazykouki, but I couldn't disagree with you more. No way in hell it would be half as cheap to make a RB20 make the same power (500hp) a SR would. Also, you don't like your RB25, especially compared to your RB20? That just baffles me.

I could sit here all day and argue till I'm blue in the face but the facts don't lie...I was talking to a friend the other day and he didn't believe that an RB26 has seen over 900 WHP on a completely stock long block until he found it for himself today, found out the RB26 had ran numerous 7 second passes. The most power I've seen out of an RB20 with a stock bottom end was 533 WHP out of a completely stock RB20.

Now I cannot say that they would be reliable but all things considered, if all you did was throw some pistons and rods into the mix, it WOULD be reliable. It's a combination of tuning and parts.

As for the RB25...I just f*** hate the thing...its a POS truck motor and I've never seen an RB25 come apart for a refresh that did not have fractured pistons.

[danielmcn]

I really dont see how you can say the sr20 is any better at making power then the rb20. Fack is the rb20 would be better. Think about this, at 400hp on the sr20 you need to make 100hp per cyl. On an rb20 with the same power its 66.6666666666666, thats 33% less per. If you use more pistons and rods to do the same work t makes the job less stressfull on the moving parts.

[TheRBguy]

You can run well over 400hp on a stock sr bottom end people do it all the time.

[Jimefam]

I'm not trying to sound like a d*** Krazykouki, but I couldn't disagree with you more. No way in hell it would be half as cheap to make a RB20 make the same power (500hp) a SR would. Also, you don't like your RB25, especially compared to your RB20? That just baffles me.

Krazy is just upset that his 25 sucks. He is still mad my 25 beat his when I had 4 pistons with broken ring lands.

[danielmcn]

I'm not trying to sound like a d*** Krazykouki, but I couldn't disagree with you more. No way in hell it would be half as cheap to make a RB20 make the same power (500hp) a SR would. Also, you don't like your RB25, especially compared to your RB20? That just baffles me.

Krazy is just upset that his 25 sucks. He is still mad my 25 beat his when I had 4 pistons with broken ring lands.

LOL that funny.

[Cjmartz2k]

IIRC Rb25's weigh the same as RB20's. The might even be a little lighter since there is more missing from the block due to bigger bores

I really dont see how you can say the sr20 is any better at making power then the rb20. Fack is the rb20 would be better. Think about this, at 400hp on the sr20 you need to make 100hp per cyl. On an rb20 with the same power its 66.6666666666666, thats 33% less per. If you use more pistons and rods to do the same work t makes the job less stressfull on the moving parts.

Are you seriously going to use that kind of reasoning? I'm in a really good mood today so I'm going to step out of this thread with out being an a**. I think the OP understands my points and can choose to listen to who he wants.

One last thing, I also have owned all 3 motors. RB20 would be my last choice of motor for every kind of motor sport. The only way I would play with one is if it was already installed in the car and I was on a budget. Both of which were true for me at the time.

[danielmcn]

IIRC Rb25's weigh the same as RB20's. The might even be a little lighter since there is more missing from the block due to bigger bores

I really dont see how you can say the sr20 is any better at making power then the rb20. Fack is the rb20 would be better. Think about this, at 400hp on the sr20 you need to make 100hp per cyl. On an rb20 with the same power its 66.6666666666666, thats 33% less per. If you use more pistons and rods to do the same work t makes the job less stressfull on the moving parts.

Are you seriously going to use that kind of reasoning? I'm in a really good mood today so I'm going to step out of this thread with out being an a**. I think the OP understands my points and can choose to listen to who he wants.

One last thing, I also have owned all 3 motors. RB20 would be my last choice of motor for every kind of motor sport. The only way I would play with one is if it was already installed in the car and I was on a budget. Both of which were true for me at the time.

And this is your opinion, based on who knows what. Mine is based on the fact that if you have two motor of equel size the one that has less cyl has to work harder to get the same hp. I dont see how its sooooo hard to understand.

[twotonedrift]

thanx crazykouki, and danielmcn makes a valid point.... thats why i dont understand why rb20s are less popular for building unlike an sr20... i always figure rb20s stock were reliable and decent in power. therefore thinking that it shouldnt b hard to ring power out of them. especialy compared an sr. . but one of the biggest reasons i was leaning towards the sr was because of there parts selection and availability and write ups. . i would b worried that i wouldnt have enough sources or anything to rely on if i started tearing in to an RB like that. . but i will say that if it can be done safely with an rb, id prefer that over an sr any day. . they have just always been my preference. .

I have never heard of a stock RB20 bottom end handling 533whp. but 400 mabee. . if this is true, i would deffinately forge the bottom end for reliability and call it a day on my power expectations...

[Cjmartz2k]

4 or 6 banger has nothing to do with it. That logic is flawed. How about a 4G63? Would you rather have an RB20 over one of those and try to make tons of power? Research how much people make on them. The RB20 is hard to make a lot of power with. The head flows like crap. It's also expensive for parts. The SR is cheaper and will make 500rwhp+ all day long, as MANY people have proven that. Maybe there is a person or two out there with a 500rwhp+ RB20, but I haven't seen it, and it sure isn't common.

Okay, 500hp divided by 6 is less than divided by 4. How about the fact you need to run more boost or a bigger turbo or rev the RB20 higher to make the same power? Well, now your math doesn't add up. I'm speaking from experience, not what I learned in 4th grade math.

[RustspecS13]

Hey did you know that a SR and RB20 pretty much have the same transmission. So if you make 500whp with an SR, its on a pretty weak trans. You can do the same with an RB20. 500whp, on a s*** trans.

But then you can bolt on a stronger trans to a RB block. 25/26 trans can hold way more power more reliably. Look at what a mount kit is for an SR, to adapt a Z32 trans to it. Then add that cost to a 500whp SR setup. You'll never have that problem with an RB, its a bolt on.

If you love your RB so much, buy a spare rb20 long block. Upgrade your turbo/injectors/tune etc etc and make as much power as you want. Make your 500whp. Screw it, you have a spare. Then when/if it blows throw in the spare, turn down the boost, and see what broke. Dont take our word for what that motor can take, just find out for your self. Just find a good tuner.

Also you have an RB now. Bolt a RB25 to your trans, and not mess with that other stuff. Or bolt a 25 trans to your 20, and start making more power. You wont have to worry about the trans at that point.

Either way, a rb25 or 26 is a great option. You can even do half at a time, while still working to your goal the entire time. I think most SRs sound like s***. Like my friends, he just built it, turbo upgrade blah blah blah. It sounds like crap now. The engine note sucks, and the power band is now tiny. Mildly built RB's can rev out all day long and make good power every where.

~Alex

[danielmcn]

4 or 6 banger has nothing to do with it. That logic is flawed. How about a 4G63? Would you rather have an RB20 over one of those and try to make tons of power? Research how much people make on them. The RB20 is hard to make a lot of power with. The head flows like crap. It's also expensive for parts. The SR is cheaper and will make 500rwhp+ all day long, as MANY people have proven that. Maybe there is a person or two out there with a 500rwhp+ RB20, but I haven't seen it, and it sure isn't common.

Okay, 500hp divided by 6 is less than divided by 4. How about the fact you need to run more boost or a bigger turbo or rev the RB20 higher to make the same power? Well, now your math doesn't add up. I'm speaking from experience, not what I learned in 4th grade math.

lol my logic is not flawed..... Its simple. Who is talking about 4g63s? They are good at one thing and thats being on a dyno, time they are off they blow up..... The head may flow like crap on the rb20 and it may not be cheaper to build then the sr20, but that does not make it a worse motor to use. I dont know anyone that builds race cars (sub 6 sec 1/8 mile) that would even think about leaving the head stock. THATS WHERE THE POWER IS MADE. The botom end just holds power it does not make it. This car see full boost at 3800-4000 and makes 449 at the wheels on a stock block with a ported head ( so says the owner). http://www.youtube.com/watch?v=QKESFO0J ... re=related

[danielmcn]

If its cheap power your looking for just put a v8 in it and call it a day............

[twotonedrift]

im leaning more on what danielmcn is saying...i deffinately do not wanna go v8, and am fully aware that it will cost money to build any motor...i think i have gathered enough info from all of you to base my decision. thanx guys.... like i said before, the only thing that kind of bothered me, was the fact that Rb20s dont have a rep for being built... everyone around my town will make it a point to tell me, " how many rbs do you see used by pros" or " theres a reason why EVERYONE uses sr's, cuz rbs suck" lol... got in my head a little bit... when you get told rb20s are garbage all the time, you tend to rethink you plans....

If that is the case, it would b cool to prove everyone wrong and b one of the few...also because i already have the swap anyways. .. thanx again guys...please feel free to give me any extra info if you have it.... i dont think ill be sellin' my swap anymore..

[RustspecS13]

Hey I enjoyed my RB20. Its a FANTASTIC engine. Super strong, makes great power vs some other engines of its era. Great potential.

Then you get down to the facts. You need to port and cam the head to make much better power. Over sized valves and major porting helps a lot. The Rb25 flows a lot better. Also has much bigger valves and port size to go with them.

Then also the RB25/26/30 has much bigger bores. Bigger bores = less valve shrouding. That means the sizes of the bore is too close to the valve, and it cuts into your flow.

I think EH? is making 550RWHP or 450RWHP on a stock RB25 head. Basic setup, forged rods and pistons and a freshed up head (or something like that- i could be off). Thats pretty common in the 25 realm.

Heck I even had a rb25 with a bad head. I considered a RB22, and stroking it with the 25 crank. The money put into that could have fixed the 25 and put upgrades on it. Just not worth it in $$ to HP ratio.

I love my old RB20. But its just no match for a 25/26 because nissan had more room to work with.

~Alex