RB20 Swap Info

[DKZenkiS14]

Guys I've been out the 240 game for a minute. But my cuz just bought a 91 5 speed and is talking about doing a RB20 swap cause his boy keeps saying "do a rb20, Better then SR or a ka-t"

Now when I had my 95 all the talk about RB20s were they weren't worth it. Has this changed? When I did a search on here all I found was for sale threads. Any info you guys could share would be greatly appreciated. Or if you could point me in the right direction that would help. I just don't want my cuz to make the wrong choice.

[DKZenkiS14]

No input from anyone?

[Sileighty_85]

Build your car for YOU, not for what everyone else thinks is cool

if your gonna do a 2.0 swap it might as well be the SR20, less maint, and no clearance issues

[kiss my bumper]

its to each his own. i love my rb20, for a few reasons. the bill installed is less than if you where to do other swap properly. great balanced power feel. the sound of the straight six is bliss. and last you can say. " I got a skyline motor bitch."

[kiss my bumper]

Build your car for YOU, not for what everyone else thinks is cool

if your gonna do a 2.0 swap it might as well be the SR20, less maint, and no clearance issues

maint is about the same. but you are so right on the clearance issue. i have to drain my radiator every time something happens

[towlie]

Rb20's are a BIG motor. 450ish pounds of iron six cylinder, of you do the swap spend some time compensating by choosing correct spring ratings for your coilovers. Expect about a half inch of clearance between the head and firewall.. Any major front end collision and you'll have a motor through your dash, lol. IMO the rb20 is a good motor with potential but not quite worth it because they are low displacement. Might aswell get the SR and have better balance or the rb25 and MOAR power

[redline racer510]

A little bit more $ and you can get rb25 correct me if I'm wrong the rb20's don't have vct which means less bottom end torque which is the primary reason for going from a 4 to a 6cyl other than that stick with the KA.

[rb20dett]

rb20 are the shet if u want a strait 6 vs 4 u b the judge

[redline racer510]

Having 1/2 liter less displacement, no vct and a crappy tranny is not "the shet" lol. At best they are alright. Save your money and like what sileighty85 said above, build the car for you not because your home bro cousin dude said so.

[Darren]

the biggest 2 factors for me, was fit and weight. The sr20 weights a lot less than both the ka and any of the rbs, and it sits back further in the bay (less weight up at the nose) so if you want to do any kind of motorsports, you'll benefit from a closer to 50/50 weight split (not sure exactly what it comes out to...)

Also, because the sr20 ACTUALLY CAME IN THE S chassis, it requires no special mounts, no clearance issues, etc... and they're a bit cheaper IIRC...

QFT:
Having 1/2 liter less displacement, no vct and a crappy tranny is not "the shet" lol. At best they are alright. Save your money and like what sileighty85 said above, build the car for you not because your home bro cousin dude said so.

Good luck with the build

[DKZenkiS14]

If I was gonna build one i would want a rb25 or just do a sr. But its my cuz's car so i'm just trying to do some additonal research for him.

[ChicagoS14]

I personally favor an inline 6 engine to a 4 cylinder engine due to multiple factors. First off the i6 engine will deliver a smooth and balanced powerband all the way to redline. The low end power of an RB20 wont be as impressive as the SR, but right aroudn 3000rpm the RB will start to pull like mad. Very similar to a CA18 as the CA18 is essentially a 4 cylinder RB engine.

The valvetrain on RB engines is far superior to the SR. SRs have rocker arms while RBs use buckets just like JZ, KA, CA and similar engines. You can rev the shit out of an RB and the head will outlast a stock SR head any day. To make an SR rev high reliably will cost you $.

The swaps are practically the same. Wiring is about the same, only major difference between the SR and RB is that you will need motor mounts. You can reuse the driveshaft with a 20, but need a custom driveshaft for the 25. Yes the fit will be tighter in the engine bay, but if you know what your doing you will be able to clean up the engine bay enough to have easy access to all the major parts. Plus its not all that complicated of an engine. As far as maintenance and reliability again ill take the RBs over SRs. Way less problems and downtime. Only major weak points are stock ceramic turbos, the coil packs and the crank collar. Other then that you can get parts from USDM cars without major issues.

The only major "advantage" to an SR is a large list of used and new parts available stateside although there are more and more RBs so this is changing. Also the SR weights less. However if your smart and know what your doing you can balance the car and with enough power you will easily overcome the weight issue.

Plus the soundtrack of an RB just owns the SR. Im sorry but most 4 cylinders sound like ass.... I had a KA-T, I build KA-Ts, I swap SRs, RBs, JZs, LSx etc on a regular basis and by far I love the straight 6 sound. I would go as far as saying that the RBs sound better then JZs.

But as pointed out earlier the major issue is doing what you want to do. Choose the swap you will enjoy and fits your needs. Budget wise compare each swap cost and see what you can handle. Dont half ass a swap and enjoy the motor for yourself and not others.

[ChicagoS14]

A little bit more $ and you can get rb25 correct me if I'm wrong the rb20's don't have vct which means less bottom end torque which is the primary reason for going from a 4 to a 6cyl other than that stick with the KA.

Not quite... it will cost a lot more money for a 25.

Going rate on RB20 is 1300 or so. The 25 is about 2000 - 2500 for motor and trans. Then you need a driveshaft as well. So the 25 is over 1000 more then the 20.

[Pandapants]

I like my rb20 pretty much only because it's an rb. My total bill after the swap was cheaper than the kae-t I started piecing together, and most likely cheaper than an sr20. If I could do it over again, I would have finished the kae-t; More torque and usdm goodness.

[redline racer510]

Not quite... it will cost a lot more money for a 25.

Going rate on RB20 is 1300 or so. The 25 is about 2000 - 2500 for motor and trans. Then you need a driveshaft as well. So the 25 is over 1000 more then the 20.

You forgot to factor in the use of a rb25 trans as the rb20 trans is pretty much a ka/sr trans with a different bell housing sooooo, 1300 for rb20+ 500-700 for rb25 trans= rb25 (I paid 2100 for my rb25) you get the picture. For what it cost to replace the crappy rb20 trans you can get the 25 that in my opinion is alot better than the 20.

[speedfreak90]

i love my 20, has bin a great motor. gets a shit ton of attention. drifts well, revs smooth, and isnt to hard to work on. i mean somw things are a pain in the ass but every motor has its ups and downs. as stated above its all in what u are looking for in ur swap and what u want out of it...

[karl wasabi]

If you're gonna go with an RB series motor, go with an RB25. I have an RB20 myself and I love the motor, but if I were to do it again, I would go with a 25.

[redline racer510]

If you're gonna go with an RB series motor, go with an RB25. I have an RB20 myself and I love the motor, but if I were to do it again, I would go with a 25.

CASE AND POINT. For the love of god do whatever you want don't take any of my opinions or anyone else's for the matter in deciding what you want. Hell put a turbocharged lawn mower engine if that's what you want. This thread reminds me of my first couple of threads when I first joined zilvia.

[accidentalymet]

Fuck all that shit ls1's for life!

[redline racer510]

fuck all that shit ls1's for life!
spoken like a true rebel lol!

[DKZenkiS14]

I personally favor an inline 6 engine to a 4 cylinder engine due to multiple factors. First off the i6 engine will deliver a smooth and balanced powerband all the way to redline. The low end power of an RB20 wont be as impressive as the SR, but right aroudn 3000rpm the RB will start to pull like mad. Very similar to a CA18 as the CA18 is essentially a 4 cylinder RB engine.

The valvetrain on RB engines is far superior to the SR. SRs have rocker arms while RBs use buckets just like JZ, KA, CA and similar engines. You can rev the shit out of an RB and the head will outlast a stock SR head any day. To make an SR rev high reliably will cost you $.

The swaps are practically the same. Wiring is about the same, only major difference between the SR and RB is that you will need motor mounts. You can reuse the driveshaft with a 20, but need a custom driveshaft for the 25. Yes the fit will be tighter in the engine bay, but if you know what your doing you will be able to clean up the engine bay enough to have easy access to all the major parts. Plus its not all that complicated of an engine. As far as maintenance and reliability again ill take the RBs over SRs. Way less problems and downtime. Only major weak points are stock ceramic turbos, the coil packs and the crank collar. Other then that you can get parts from USDM cars without major issues.

The only major "advantage" to an SR is a large list of used and new parts available stateside although there are more and more RBs so this is changing. Also the SR weights less. However if your smart and know what your doing you can balance the car and with enough power you will easily overcome the weight issue.

Plus the soundtrack of an RB just owns the SR. Im sorry but most 4 cylinders sound like ass.... I had a KA-T, I build KA-Ts, I swap SRs, RBs, JZs, LSx etc on a regular basis and by far I love the straight 6 sound. I would go as far as saying that the RBs sound better then JZs.

But as pointed out earlier the major issue is doing what you want to do. Choose the swap you will enjoy and fits your needs. Budget wise compare each swap cost and see what you can handle. Dont half ass a swap and enjoy the motor for yourself and not others.


You forgot to factor in the use of a rb25 trans as the rb20 trans is pretty much a ka/sr trans with a different bell housing sooooo, 1300 for rb20+ 500-700 for rb25 trans= rb25 (I paid 2100 for my rb25) you get the picture. For what it cost to replace the crappy rb20 trans you can get the 25 that in my opinion is alot better than the 20.


Thanks guys. Again keep in mind its not my car. I'm just doing some research for my cuz. I do plan to buy another one soon now and i know what swap i wanna do.