SR20DET or RB20DET

[Murry33]

RB20DET feels like its got more get up and go than the SR20DET........it's probably simply because the SR is a 4 cylinder. I like the sound of the RB20DET more though, and well yeah the torque you will definately notice on the RB more so.

[pentae]

Neeesan: The RB20DET sounds like its got more get up and go.. the SR20DET actually does

They are both brilliant engines.

[IOWNU]

RB20DET feels like its got more get up and go than the SR20DET........it's probably simply because the SR is a 4 cylinder.

But isn't the RB20 a 4 cylinder also? I just think the RB20 sounds better coz of the way its designed. 'Race Bred'

[slow13dude]

But isn't the RB20 a 4 cylinder also?  I just think the RB20 sounds better coz of the way its designed. 'Race Bred'

RB engines are inline-6 cylinder engines.

[Cool Hand Luke]

Remember also you say the RB is cheaper to buy, but if the car already has the SR in it, there is no need to buy it. The RB does sound better (actually a modified SR sounds really tough, has a real raspy note), but the despite what a few people wrote, has less torque.. much less, its easily notciable. Also if you go with the RB, its only comparable to the SR if you change to the RB25 turbo.

I've personally owned both, the RB20 having arouns 190rwkw and the SR 270rwkw and driven a lightly modified SR.

To get the wheels to spin or take off from a rolling start in the RB, you would always have to fan the clutch, if i raced an sr and didnt do this, i would loose a couple of car lengths (the sr's neednt do this). I found driving the cars normally both SR's used less fuel because you could roll around a corner in 2nd at 1500rpm and accelerate slowly without the car loading up, not really possible in the RB. Also because the RB has less torque you are using more throttle, without the tuned ecu the RB was horrific on fuel, and bear in mind the SR had much bigger injectors.

The other thing is weight distribution, and it IS noticable. Putting heavier springs does not change weight distribution.

They both have their goods and bads, its just a matter of working out which ones are important for you, and others not, then make your descision on that! Good luck

[someonestolecc]

RB does not stand for race bread- I think that's been theorised on this forum to death.

Also RB20 have LESS torque in the majority of the rev range ffs.

Where do these people get these "facts" from?

[edit: Cool hand luke is right on the money]

[PRO-L20]

The SR20 has 5nm of torque more, right?

Putting in an RB20 should give more turn in understeer which could be better for modded applications.

[jazza08]

sr20 does have more torque, ONLY noticeable because its in an s13. Put an rb20det in an s13 and it will SEEM to have more torque over the r32 due to the weight! People forget that... the rb20 can rev alot happier.

Compare and s13 (redtop) sr20 to an rb20 and the rb20 will be a better engine producing more power with similar torque levels.

Compare an s14 or s15 (blacktop) sr20 with an rb20 and the sr20 takes the cake, newer and further engineered, not to metion the bigger turbo! But this isnt really fair as your compairing a newer engine to an older one, put an rb25 turbo onto the rb20 and it will compete better with an s14 engine... you get the idea!

Id say stick with the sr20 as its made for the car, however if you choose an rb20 for whatever reason you'll be happy with the more rpm you can go through freely and you wont loose much driveabiltiy as it is only noticably unhappy at lower rpms as its in a heavier (R32) car than the sr20 (s13)!

[funkymonkey]

stick to an SR20 engine, as said before the RB20 bolt ons do not bolt on so easily when its placed into a silvia. One of my mates has a RB20 in his 180sx, and I just recently had the pleasure of fitting an oil filter relocation kit to it. I can tell you for a fact that there isn't much clearance in the fornt of that engine bay (so much so that the intake piping had to be redone so it didn't hit the bonnet).

Stick to the SR20... awesome engine, plenty of mods available, good tuning support, tried and tested with proven results. As a bonus Nissan Japan spent millions of dollar developing your car to suit an SR20. Don't go reinventing the wheel because some "american knob jockey-ex honda owning-now drift bandwagon jumping-forum know it all" seems to think its cool.

If you want a choice of SR20 or RB20, and you want the suspension setup of a silvia, and the FACTORY RB20, then buy a cefiro. I've seen skylines and ceffy's with SR20's swapped in where you can almost stand in the space between the engine and the car.

[Roy]

Out of interest, has anyone ever seen a dyno comparison of a std turbo RB20 vs SR20?

I think it would be interesting. Dont forget that the SR gearbox has different gearing to the RB20 box. Have different diff ratios. (well my R32 has different ratios to a friends old S14)

Also the cars have different body weights, ie S13 v R32.

So put my bum in an S13 with an SR20 and RB20 gearbox and std S13 diff ratio...then put me in another S13 with an RB20 with RB20 gearbox and std S13 diff ratio. Both with std turbos and say for the sake of the argument similar intercoolers, exhausts and Power Fcs tuned by the same tuner:)

I would love to know which engine is punchier/torquier:)

[Roy]

For the record, if your car has an SR20, i say stick with the SR20:)

[jazza08]

Heres a comparison i found in a mag.

SR20 - Garret GT28 b/b turbo, ARE intercooler/stainless intercooler piping, 3' custom SS exhaust (inc 3' cat), SS Manifold, Standard ECU

Result - 208rwkw (280hp)

RB20 - HKS GT 25/35 b/b turbo, ARE intercooler/stainless intercooler piping, 3' custom SS exhaust (inc 3' cat), Standard ECU

Result - 203rwkw (275hp)

Im not sure what model SR20 this is as its got painted rocker covers, id suspect a later model simply because 3/4s of 180s do not have their original engines... but its a comparison!

Shows the RB and SR make very similar power as the SR has a manifold and slightly more power. Ive always seen them make very similar power! As i said before if you put an rb25 turbo onto an rb20 then it may compete with the s15 (sr20 using t28) alot better (even though the s15 also got vvt), however Nissan decided due to making the r33 a boat (even more so than the 32 that is..) 500cc and more compression was needed But thats another topic all together! hehe

[neil_se]

Ok, i've had an rb20det s13 and an sr20det s13. Same diff ratio.

The sr20det still has more torque, even with a laggier turbo (2540 on the sr, 2530 on the rb). The rb20det reved out much better though. It probably has a lot to do with the better suspension in my current s13, but this one handles like a dream, literally jumps side to side on the road, perfect response, whereas the 180 was sluggish to turn. Never pushed hard enough to notice under- or over-steer.

[jazza08]

Ye, i think its obvious from examples aswell as just general consent that the sr20 has more torque but wont rev like the rb20. Id say an rb20 into a 180sx would mess up suspension and unless you have adjustable coil overs to counter this its not worth it (unless you only want it for straight line duties..)

[someonestolecc]

The SR20 has 5nm of torque more, right?

Putting in an RB20 should give more turn in understeer which could be better for modded applications.

SR20 has more torque over the rev range, not talking about peak power.

If you want turn in understeer use proper suspension settings, not weight. That's like saying "you wan't turn in understeer and cant afford a heavier engine? use a bag of cement."

C'mon mate

[Roy]

Ok, i've had an rb20det s13 and an sr20det s13. Same diff ratio.

The sr20det still has more torque, even with a laggier turbo (2540 on the sr, 2530 on the rb). The rb20det reved out much better though. It probably has a lot to do with the better suspension in my current s13, but this one handles like a dream, literally jumps side to side on the road, perfect response, whereas the 180 was sluggish to turn. Never pushed hard enough to notice under- or over-steer.

Interesting, but what are the SR20 gear ratios. RB20s are:

1st - 3.321

2nd - 1.902

3rd - 1.308

4th - 1.000

5th - 0.759

Std diff ratio - 4.363

Not trying to argue or anything, just want to be sure that the facts are the facts, i suspect they are...bu ti know form my friends S14, it was a little bit punchier then my car, but it also plateaud a lot earlier which seemed to pronounce the mid range more vs the Rb20 that was more linear through to the extra 750rpm or so.

Anyway, thats a silly example as his S14 v my R32 has different gearing weights etc etc

[Steve]

SR, cheaper to mod, better toque. Torque is derived from the rod ratio, or the stroke length.

But the Rb having a shorter rod, will rev out more when pushed without having the worries of rocker driven valves. If you compare the F1 engines, which have very short stroke length, or a motor bike engine - they are quite happy to rev their nuts off. The SR has a stock redline of 7500rpm though, which isnt too bad.

Doesnt get away from the fact that an SR is much cheaper to mod, manifolds are cheaper, injectors, only need 4 instead of 6, cams are cheaper, and if you are doing a full rebuild, 4 pistons and rods are definately cheaper than 6.

Some food for thought.

[jazza08]

Ye ofcourse, but its not only due to the rods... remember another 2 cyl and another 8 valves help top end breathing and also help in regards to the engine being smoother running than an sr20. But there is alot more aftermarket parts to suit sr20 as it was in production for so much longer! Not that theres a shortage of rb20 parts or anything...

[funkymonkey]

hehe good to see some level headed responses rather than "RB OR DEATH... RB20 POWAH!" posts. You guys never cease to amaze me.

Also if you had to get some work done on your engine internals (lets assume you need to oversize the bore) you only have to pay for work done on 4 chambers instead of 6. Add to that the fact that there are more turbo packages available for the standard SR20 manifold.

RB20's are the king of DIY engines, and SR20's are the king of bolt ons.

[Roy]

LOL..you can get 2.2L out of an RB20 just by boring it, need a crank to do that with SR20:)

Anyway SR20 is the go if you have one in already have one in an S13