RB30 bottom ends

[Guest JAMIE T]

Here is the link to the "thrashing." As you will read the "thrashing" was done by the top experts in the field of head porting.

http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB4&Number=68098086&page=0&view=collapsed&sb=5&o=&fpart=1

I honestly believe I would have gotten away with it if it wasn't for those meddling kids.

 

I apologize if my comments were "synde" and you are correct; once I discovered I had wasted all that money on the 2.6L bottom end I had no choice but to try and make your efforts to build a 3L bottom end seem pointless.

 

For me to state that you gain no additional flow because the cylinder bore is the same size as the RB26 bottom end was not called for and rude. For me to say' date=' "Because of the head flow I would prefer the extra revs" was just plain selfish. I should have asked you if you wanted some of those extra revs instead of trying to hog them all for myself. Also, knowing that I hate torque, for me to state that you gain torque and displacement at the expense of rpm was baseless and hypocritical. Finally, for me to say, "after discussing with Endyne I decided it wasn't worth it for me" was really the straw that broke the camel's back. I completely understand if you never forgive me for making such bold comments about my project. For that I deeply apologize to you and to everyone else who wanted to see me build the 3L bottom end.

 

I have done a lot of soul searching on this one and I think this ordeal will ultimately make me a better person. Also, I am thankful that we live on opposite sides of the US because if I were to ever run up against you on the street I have no doubt I would be humiliated. You would probably be 100 yards down the road before my car even thought about making boost.

 

I don't like being punked and Brian, you punked me good on this one. You've made me re-think things. Whether you meant to or not, you've done me a favor. Thanks.[/quote']

 

Have you sought counceling? You should...

[Clifton]

For someone like you who is not wanting to make any real power I think the RB30 bottom end is the perfect choice.

 

 

An RB30 with an RB26 head will surely make more power than an RB26. Who's to say you can't rev an RB30 If the head's are the same and have the air in them.

 

Not Nissan but related. A 2.5l 1JZ makes good power, alot of guys want more power out of them so they use 2jz blocks (longer stroke) with the 1jz head(cheaper). They call it a 1.5jz. The added discplacement doesn't hurt power. A straight 2jz with an 86mm stroke are revved past 8k often with stock rods, a few higher. I know the 1jz has the same output of the rb26, in stock form. The longer stroked 2jz(3.0) will make more power comparred to both the smaller but higher revving 1jz or rb26. There are also stroker kits that bump them to 3.4. They make even more power.

[Zhadman]

The RB30 had harmonics issues over 7500rpm. It's been awhile since I did all my research on the motor, so I don't recall (offhand) whether or not it was an issue with the crank, crank girdle, or rods. Trying to make an RB30 rev past that point may be prohibitively expensive. Like James mentioned, though, 99% of street drivers will never need to rev the motor to, or beyond, this point.

[cheftrd]

James, that's a nice shop. Looks kind of like mine!

[cheftrd]

An RB30 with an RB26 head will surely make more power than an RB26. Who's to say you can't rev an RB30 If the head's are the same and have the air in them.

 

Not Nissan but related. A 2.5l 1JZ makes good power' date=' alot of guys want more power out of them so they use 2jz blocks (longer stroke) with the 1jz head(cheaper). They call it a 1.5jz. The added discplacement doesn't hurt power. A straight 2jz with an 86mm stroke are revved past 8k often with stock rods, a few higher. I know the 1jz has the same output of the rb26, in stock form. The longer stroked 2jz(3.0) will make more power comparred to both the smaller but higher revving 1jz or rb26. There are also stroker kits that bump them to 3.4. They make even more power.[/quote']

 

Sorry man, an engines power is limited by the head (ports and valve events). If a head will make 600hp and you put a bigger block under it, it will make around the same power, but at a lower rpm. Sometimes it will make less power if the head is optimised for the higher revs of the smaller engine. This is probably not the case with the RB30 (more on this later).

 

In the case of the 1.5J, the reason people use the 1J head is engine management. The old 1J uses two cam sensors and the 2J uses 1. To swap in a complete 2J would require swapping engine management, as well. Not fun in a Toyota and it would be full of bugs with your Aristo ECU trying to control all of the Mark II stuff. Guys running stand alone are all running complete 2J's. The Complete 2J makes more power than the 1J because it has way bigger ports and way bigger valves; the head is optimised for the 3 liter. By putting the 1J head on the 2J bottom end, all they're doing is killing VE. When you kill VE, you kill compression, as well. Also, you can't compare the crank and rods in any RB engine to the J motor parts. J motor cranks are fully counter weighted vs. semi counter RB's. The Toyota rods are like aftermarket dowled, cap-screw, I beams, from the factory. Stock Nissan rods are waaay inferior. That's why you can rev the hell out of the 2J. To rev like this with the RB30 stroke, you need better parts. I'm not saying the RB30 is bad, just can't compare it to the Toyota J.

 

Torque is power. Power is torque. Power is what accelerates something. Torque is a measurement of a static force (not moving). When we say "more torque", we are generally referring to an engine that makes more power at lower revs. If you have more torque and the engine feels faster, it's because it has more power. As torque is a static force, you can't feel it. This is something that really bothers me. It seems that 99% of people don't understand the power/torque relationship.

 

The toruqeless RB26 syndrom... People talk as if a built RB26 can't even be driven; you need a pit crew to push it off the line every time you have to stop. I've driven/tuned some pretty powerful RB26's. Can't give exact power figures, but enough to break all four wheels lose from 100MPH and bury the speedo at 320km/hr on the expressway. I assure you, even this car can be daily driven. When I snap the throttle to max at 2500rpm, it pulls away faster than my wifes Y2K Toyota mini van. I would call that acceptable "torque" for a daily driver. As far as the street race between the 30 and the 26, if they snapped to max at 3000rpm, yea, the 30 would smear the 26. On that note, who races like that? If you have an engine that make power at 8500, that's where you race it. 99% of race engines never see the max torque rpm when actually racing.

 

Here's the "more later" part: Although I have never built or even studied the RB30, I know the 26 and I know 86X86 bore/stroke dynamics. The Stock RB26 head way outguns the 2600cc displacement. If it were a head that flowed at or near the potential of the 26 it would be a joke to put it on the 30. You would gain nothing. However, because it flows too much for the 26, it will respond well when put on the 30 bottom-end. Without using the nasty "T" word, you will end up with a fatter POWER BAND. Power band is more important than peak power, as we don't race at a single RPM. We race across the gear spread. If there is a 2000 rpm drop from first to second, the engine with the best AVERAGE power across this spread wins the race. That's where power band is important.

 

That said, the fastest GT-R on the planet uses the 26 block and is a 2.8.

[Clifton]

In the case of the 1.5J' date=' the reason people use the 1J head is engine management. The old 1J uses two cam sensors and the 2J uses 1. To swap in a complete 2J would require swapping engine management, as well. Not fun in a Toyota and it would be full of bugs with your Aristo ECU trying to control all of the Mark II stuff. [/quote']

On the boards I'm on it was originally believed the 1j head flowed more. That's why many ran it. The other reason is 1j's are usually run by the MKIII crowd. They tend to be a little cheap(many will ateast to that) and the 1.5j is a cheaper swap. I don't know about the MKII's stuff, not too many jz powered ones here..

 

The Complete 2J makes more power than the 1J because it has way bigger ports and way bigger valves; the head is optimised for the 3 liter. By putting the 1J head on the 2J bottom end, all they're doing is killing VE.

Right. My point was a 1.5jz still makes power than a 1jz, even with the added displacement.

 

Also, you can't compare the crank and rods in any RB engine to the J motor parts.

Just an example comparring displacement and power.

[cheftrd]

The 2J head outflows the 1J head by a mile. The reason for the 1J head on the 2J is exactly what I stated; it's an engine management issue. When I am referring to the MK II, I mean the Toyota Mark 2/Chaser/Cresta. From the JZX90 on, they are mostly 1J's. This is the popular car in Japan for the 1.5J swap.The 1.5J doesn't automatically make more power just because you increase displacement to 3.0 liters. They make more power because 99% of the people doing this swap also use big cams and big turbo kits. 99% of the 1J crowd, here in Japan, is still on the boost-up, muffler, and air filter menu. I've seen 700hp 1.5J's and I've built 700hp 1J's. The difference, as I stated earlier, is that the 3.0 makes the power at a lower RPM. Now that stand alone EM has caught on in Japan, I never see 1.5J swaps anymore, it's always the complete 2J.

[Clifton]

The reason for the 1J head on the 2J is exactly what I stated; it's an engine management issue.

Maybe in Japan but that's not why they were doing it here.

 

 

The 1.5J doesn't automatically make more power just because you increase displacement to 3.0 liters. They make more power because 99% of the people doing this swap also use big cams and big turbo kits.

Again, maybe in Japan but 99% of 1.5jz here are in MKIII's. 99% of those are are stock or close to it. Big cams, turbos or whatever they still make more power than a 2.5l 1jz with the same mods so I don't see your issue.

 

Another example. L6 heads don't flow much compared to alot of newer heads. Based on what you are saying about the head not having enough air for the added volume "it will make around the same power, but at a lower rpm. Sometimes it will make less power if the head is optimised for the higher revs of the smaller engine" an L stroker would produce the same or less power. Yet I have never heard of a stroker L6 motor making less power or the same regardless of how much lower it revved comparred to an an L24-L28 with stock bore and stroke. I know 7M heads don't flow well and they have a silly long stroke(91mm). Maybe if I destroked it I would make more power.

[cheftrd]

Maybe in Japan but that's not why they were doing it here.

 

You're right. They were doing it in the States because they saw all the retards in Japan doing it and thought "Oh cool JDM! Let's copy it!" without knowing why they were doing it. Why would you put an L20 head on an L28, or an RB20 head on a 25 or 26?. If you are in the States and have a complete 2J; then you paid money for a 1J head and put it on the 2J (which has bigger ports and valves), You are stupid and a victem of JDM. We call that Rice when people copy stuff out of Japan for no other reason than it's the "in thing" in Japan.

 

 

Again, maybe in Japan but 99% of 1.5jz here are in MKIII's. 99% of those are are stock or close to it. Big cams, turbos or whatever they still make more power than a 2.5l 1jz with the same mods so I don't see your issue.

 

A Toyota MARK 2 IS A FOUR DOOR SEDAN THAT COMES WITH WITH THE 1JZGTE IN THE TOURER V MODEL OR THE GT MODEL IN THE OLDER JZX 81 MODEL. I am not talking about the MK II Supra. The issue is stated above about swapping the high flow head on the engine for one that flows less. The 1J head also outflows the displacement (many Japanese engines do), so you would see a power increase by upping the displacement. You would see a huge power increase by swapping the entire engine, so what is the point of swapping the low-flow head on to the high displacement engine? Engine management in Japan; Rice in the States. This is a stupid mod IN THE CASE OF THIS ENGINE! That's the point.

 

Another example. L6 heads don't flow much compared to alot of newer heads. Based on what you are saying about the head not having enough air for the added volume "it will make around the same power, but at a lower rpm. Sometimes it will make less power if the head is optimised for the higher revs of the smaller engine" an L stroker would produce the same or less power. Yet I have never heard of a stroker L6 motor making less power or the same regardless of how much lower it revved comparred to an an L24-L28 with stock bore and stroke.

 

I wouldn't know because I've never built an L31 (diesel crank stroker) without also adding a big cam, porting, and larger valves to optimize the flow for the 3.1 liter block (who makes a 3.1 with no other mods?). As far as boring goes: Power is directly proportional to the surface area of the piston. Therefore, If you bore the L to 89mm for the 3 liter displacement, you are gaining more power from the added piston area and unshrouding the valves than from the additional stroke/displacement.

 

I know 7M heads don't flow well and they have a silly long stroke(91mm). Maybe if I destroked it I would make more power.

 

The Supra with the 7MGTE that HKS ran 7 second quarter mile times in many years ago was destroked to 2.7 liters...

 

I'm not going to expound on this with ten pages of math to bore the crap out of 99% of the people on this board. The point is this: I was telling you why just adding displacement doesn't do much for you, power wise, without additional mods, in most motors. Then I went on to explain why the 26 head would work well on the 3.0 (because it outflows the stock 26). Then I defended the 26 because of baseless claims of unstreetability (not a word) due to lack of torque. One of the guys I teach recently built a 500hp Toyota 4AG (1600cc) with head mods of my design, 300+ degrees of cam duration, low compression, huge injectors, 30+ psi of boost.... He drove it to work every day until we cracked the cylinder on the dyno at 11,000 rpm. It had very low "torque", but tremendous acceleration, and good enough manners to daily drive it. Another 4A at this power level I know of is destroked for less rod angle, and has no problems with the cylinder. Short stroke also has a place. Then I went on to tell you why the 1J head on the 2J block was popular. You never wanted to learn anything from the get-go. All you want to do is argue. It's simple (maybe no so simple) math to figure out why a head that flows a maximum (X) amount of air wil flow X amount of air, no matter the displacement under it, with all other varriables the same (vacuum, bore size, etc). If you have the same volume of air in a large and small cylinder and compress both to 10:1, which one has more compression in PSI? If you can figure it out, you have the answer to the lost power situation. You don't want to hear it because you're stuck in the "bigger must be better" box. Therefore, I won't bother to explain it. Last post on this thread.

[StealthZ]

Wow, I'm gone for a week, and what started out as a post with the very good news that RB30 blk's are being brought into the states, has morphed into me staring at Thagard's house (again), and Toyota motors.

 

Anyway, as I don't have the time or feel the inclination to justify my decision to use a particular blk for MY application, and as this thread has obvoiusly become emotionally charged... AKWIKZ (if you are still watching this thread), I will contact you privately regarding the engines.

[hat1324]

just a thought as I have been dreaming RB30 since 03, there is alot of talk about a VW belt working with the swap making it easyer to get state side..

I have alot of info compiled if someone needs somthing but basicly think higher deck height and longer stroke.

the best source I found was skylines down under and that long *** thread.

there is also a Aussie shop that will build the block over there and was willing to ship it to me.. there link is also on SDU

[260DET]

Never heard of any timing belt issues with the RB30.

[kcelectronics]

Just thought you might be interested in this?

 

http://www.users.tpg.com.au/cobra30/twincam.htm

[AKWIKZ]

Now I have some rod info. My supplier has custom sets of 4340 forged steel rods with ARP 2000 cap screws. He has had a couple of guys use these on an otherwise stock RB30 bottom end, balanced of course, and they have produced over 500hp at the wheels at 8000 rpm. $800 U.S before shipping. Probably another $60-$80 for most places in the U.S as these are coming from Australia. Just in case you guys are interested.

 

Brian

[alexideways]

As torque is a static force, you can't feel it. This is something that really bothers me. It seems that 99% of people don't understand the power/torque relationship.

 

Is'nt torque more like two opposed rotating force? If they are both the same the car accelerate and if the car puts more force than the ground trying to move under the tires, this is where a burnout occures? Thus the old saying "HP is for racing, TORQUE is for burnouts*

 

Not bragging, just asking.

[xx.jason.xx]

I love this.

 

I know a dude in OZ who can get RB30E shortblocks to me for $425 to the door.

[xx.jason.xx]

Is'nt torque more like two opposed rotating force? If they are both the same the car accelerate and if the car puts more force than the ground trying to move under the tires, this is where a burnout occures? Thus the old saying "HP is for racing, TORQUE is for burnouts*

 

Not bragging, just asking.

 

Torque is simply a measure of rotational force, and you CAN feel torque. anyone who has driven a V8 can attest to the fact that you can feel torque.

[Guest Hyksos]

Of course you can feel the torque, this is what make the acceleration, you get maximum acceleration at the peak torque, that's a fact.

 

But it's impossible to feel HP. The transmission can exploit the HP, but it's still the torque that make the car accelerate.

[alexideways]

Torque is simply a measure of rotational force, and you CAN feel torque. anyone who has driven a V8 can attest to the fact that you can feel torque.

 

I don't see where I mentioned that you CAN'T feel torque but, what I stated earlier was taken from a fragment of my memory from one of my mechanic's school books. It was the definition of torque IIRC.

 

On an other note, do you think you could hook me up with that guy to see if I can get a few here in Canada?

 

Thanks.

Alex.

[Guest kabestuble]

Hey Brian, am interested in a block or two, shoot me an email so we can hook up. head2na@yahoo.com.

 

Chris.