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-   Other Engine Conversions - non V-8 (https://www.rx7club.com/other-engine-conversions-non-v-8-118/)
-   -   Rb20det ==> Fc3s (https://www.rx7club.com/other-engine-conversions-non-v-8-118/rb20det-%3D%3D-fc3s-767283/)

veedubbed 06-27-08 10:45 PM

Rb20det ==> Fc3s
 
Sold my 13BT swap today, ordering my RB20 swap in a few days. Should be interesting. I've seen the SR20 done a few times, so wanted to try something I have yet to see.

As far as getting it in, I know the oil pan is going to have to be modified, as the RB20 has a forward-facing sump. I'm hoping just to be able to cut and flip the pan so the sump is in the back, and fab up a pickup tube for it.

After that, I'm going to drop it all in and see where it sits when the shifter is lined up. I'm *REALLY* hoping that I can retain the stock radiator position in the FC, but if not, oh well, I've had to do worse.

The motor itself is almost 3' long, so it will be a little tight, might have to do away with the heatercore for starters. I'm going to build it and try to get into drifting a little, so no heat/A/C isn't going to kill me.

Anyway, look forward to some picture when I get the swap in, might be a while before I actually start doing anything however - still looking for a garage to put the car in and work on it. If I find nothing, heck, I'll do it in my driveway (Many a swap has been done here as it is), but we'll see how that works out.

Anyone else love the sound of an RB? I know I do. Straight 3 or 4" pipe sounds like a nice exhaust I'm thinking. Hehe.

:icon_tup: :icon_tup:

Hitokiri_Gensai 06-27-08 11:21 PM

i love the sound of an RB, my buddy had a stateside legal Skyline

but still, i prefer my RX-7's rotary xD

reckless_abandon 06-28-08 03:32 PM

i love the sound of the rb series as well. and they run smooth as butter.
the only drawback of the rb20 over the sr20, is that the rb doesnt have as much torque. same displacement over 4 cylinders is better. if you were talking rb26, that would be a significant advantage.
either way, the rb swap is unique. everyone and their dog has an sr20 swap these days. go for it!

YoshiFD3S 06-29-08 12:46 AM

RB20 is fkn' trash. If you put in that POS you are insulting the FC.

At the very least, put in a damn RB25. You can make 400rwhp reliability, just by having ARP head-bolts, a steel head-gasket, and of course the right size turbo & tuning. Power FC works great with the RB25. My brother made 443rwhp/391tq on his RB25 in his Datsun 280Z. But that much power is really pushing it. He ended up going through a few motors, until he decided to give up on RB's in general.

So yeah...

RB20 = NO

RB25 = Sure, will make a safe and reliable ~350+ hp.

RB26 = If you're rich

SR20 = Good luck trying to make anything beyond 350rwhp reliably. Lame.

reckless_abandon 06-29-08 11:36 AM

you forgot RB30... thats baller status from australia.

veedubbed 06-29-08 06:37 PM

RB25 swap is $2500 up front. No thanks.

You can make 400 hp out of a '20 with ease as well. The RB series bottom ends are built to take it. Over 350 reliable out of an SR20? Try 500. I know someone who daily drives an SR20 S13 that lays down low 500's. It's not that hard.

YoshiFD3S 06-29-08 09:53 PM


Originally Posted by veedubbed (Post 8330240)
RB25 swap is $2500 up front. No thanks.

You can make 400 hp out of a '20 with ease as well. The RB series bottom ends are built to take it. Over 350 reliable out of an SR20? Try 500. I know someone who daily drives an SR20 S13 that lays down low 500's. It's not that hard.

LOL so says you.

I've seen more than enough SR's blow up on the stock motor trying to break 400rwhp. I guarantee this person you "know" isn't running a bone-stock block. That was my point.

RB20 is trash, man. I'm sorry.

And if you're paying $2,500 for a 25, then it's your own damn fault. You need better sources.

I'm not trying to be an ass, but at the same time I am, because I've seen enough bullsh*t SR's and RB's in 240's and the like, then I'd care to see for as long as I live.

Your money though. Have fun. You'll wish you had spent the extra coin on a 25 once you realize the limitations of a 2.0 I6.

SouthSideSlider 06-29-08 10:02 PM


Originally Posted by reckless_abandon (Post 8329253)
you forgot RB30... thats baller status from australia.

nice yea a RB30E+RB25DET head+T04Z = uber ballin

veedubbed 06-29-08 11:33 PM


Originally Posted by YoshiFC3S (Post 8330859)

I'm not trying to be an ass, but at the same time I am, because I've seen enough bullsh*t SR's and RB's in 240's and the like, then I'd care to see for as long as I live.

Your money though. Have fun. You'll wish you had spent the extra coin on a 25 once you realize the limitations of a 2.0 I6.


Not really worried about it, I just want to get it in and get it running. I'm looking for 350-400 at most out of this. My 08 Si is my daily driver - this car will be seeing sidewayz dayz at the track and minimal street time.

If I want to throw a 25 in later down the road, I can. I am trying not to go overboard at first here, I'm paying for the RB20 with what I got for my 13BT swap.

:dunno: :dunno:

veedubbed 07-01-08 09:23 PM

Just ordered the swap...... hopefully everything goes well with that. Motor will be getting a little refresh before going in the car as funds allow. First things first will be the oil pan situation though.

http://www.skylinegts.co.uk/images/R32-Info/RB20DET.jpg

veedubbed 07-16-08 10:40 PM

Everything showed up today. DANG this is a long motor, hope the sumbitch fits! As soon as I get my hands on a hoist, we will be hitting the road on this deal.

CrazyTrini 07-17-08 02:45 PM

Man trust me your better off with a rb20 than the rb25...sr20 would be less work and would fit nice....all those swap have been done...also my uncle did his swap with a rb20 in his FC...worked real nice. wish i could have post up some pic's but only pic's is from a film camera. good luck though. Im also gonna be doing the same thing once finish skool.

R.P.M. 07-17-08 03:14 PM

Where have you guys been?

I mocked up an RB20 block into an old FC shell I had a long time ago, it fits and the hood will close. Just barely though

http://i33.photobucket.com/albums/d8...er/pics021.jpg

http://i33.photobucket.com/albums/d8...er/pics018.jpg

http://i33.photobucket.com/albums/d8...er/pics017.jpg

http://i33.photobucket.com/albums/d8...er/pics016.jpg

http://i33.photobucket.com/albums/d8...er/pics015.jpg

http://i33.photobucket.com/albums/d8...er/pics002.jpg

http://i33.photobucket.com/albums/d8...er/pics005.jpg

Oh yeah, btw the RB20 RWD tranny will line up with the stock shift hole in the floor too.

http://i33.photobucket.com/albums/d8...er/pics020.jpg

veedubbed 07-17-08 08:56 PM

That's good to know. I measured today, and it looks like the crank pulley will be sticking about 2" into the radiator in it's stock location. Guess it's got to be moved, which I was trying to avoid doing.

Do you just have the chassis lowered around the motor, or is it actually bolted in? If it's the latter, do you have any pics of how you mounted it?

YoshiFD3S 07-17-08 09:06 PM


Originally Posted by CrazyTrini (Post 8385938)
Man trust me your better off with a rb20 than the rb25...

You're an idiot.

R.P.M. 07-17-08 10:22 PM


Originally Posted by veedubbed (Post 8387104)
That's good to know. I measured today, and it looks like the crank pulley will be sticking about 2" into the radiator in it's stock location. Guess it's got to be moved, which I was trying to avoid doing.

Do you just have the chassis lowered around the motor, or is it actually bolted in? If it's the latter, do you have any pics of how you mounted it?

There was no oil pan on the engine when I tried to fit it in, I had the block sitting on a piece of 2x4" wood ontop of the stock subframe, so you'll have 2" of room between the bottem of the block and the steering rack/subframe. I didn't take time to make mounts for it either, but it looked like it could be done fairly easily.

Your rad will definatly need to be mounted differently.

veedubbed 07-17-08 10:31 PM

Word. I was fortunate enough for the company who pulled the swap to leave the RB mounts still on the motor, so I'm hoping that part will be fairly easy (As easy as a Nissan motor into a Mazda car can be, anyway).

The oil pan, like I said, it a front-sump, and will have to be dealt with. That's what I was most curious about on yours, but you said you took it off. I will have to play around with that for sure.

As for the radiator, I might just move it forward, or play with a V-mount. That's a ways down the road though, I just want to get the motor in for now.



And no, the RB25 is far superior to the RB20. Even I know this, and only chose the '20 due to $$$$. And RB25/26 would be going in if I had the change to do it with.

EDIT - Is that the stock downpipe I see? How tight was it? I see that car is RHD, I'm wondering if the stocker is going to have to be revised to not bang up on the steering column like in a 240.

junito1 07-17-08 10:53 PM

rb20's are way better than sr's. I used to be a big nissan guy. make easier HP for less money and take the abuse way better than sr's

R.P.M. 07-18-08 10:39 AM

The stock turbo was on the head and it had the stock O2 housing I guess you would call it? Its just a short piece of exhaust that comes off the turbo and goes to a 3 bolt flange.

The FC shell I had was a RHD one, so everything cleared. For a LHD FC, the brake master would be pretty close, but it should clear the turbo/downpipe. If you build the downpipe close to the block you should also clear the steering too.

YoshiFD3S 07-18-08 04:27 PM

If you at least replace the stock POS ceramic turbo of the RB20, it's not so bad.

T3 flange.

You can upgrade the T25 of the SR to the S14 or S15 T28 to make yourself 300rwhp, with just some intercooler piping modifications. Obviously, with either motor, as soon as you replace the turbo, make sure you've got the fuel to match, and at least have an S-AFC II for A/F tuning, if you're low on the funds.

jonj 07-18-08 05:38 PM

good luck man! i used to have an RB powered s13. i like them. replace the stock turbo with an r34 or s15 turbo. and your cool.

i love straight six motors. i really want to swap a 1j into my FC. i think i'm done playing with my wankel.

veedubbed 07-18-08 10:44 PM


Originally Posted by YoshiFC3S (Post 8389459)
If you at least replace the stock POS ceramic turbo of the RB20, it's not so bad.

T3 flange.

You can upgrade the T25 of the SR to the S14 or S15 T28 to make yourself 300rwhp, with just some intercooler piping modifications. Obviously, with either motor, as soon as you replace the turbo, make sure you've got the fuel to match, and at least have an S-AFC II for A/F tuning, if you're low on the funds.



Yep, turbo will be the first upgrade. I'm not a big fan of exploding compressor wheels. 300-350 would be good for me with this project. I'm using my neighbor's garage, got my car in there today and threw 'er up on jackstands. Getting a hoist tomorrow, so I'll be playing around with trying to get it to fit in there this coming week.

veedubbed 07-20-08 10:24 PM

It's in!!!!

http://img.photobucket.com/albums/v2...3/fc3srb20.jpg


I forgot to tell you guys that I was making it FWD.....

veedubbed 07-21-08 08:20 PM

This thing is ridiculously tight, everything clears though.

http://img.photobucket.com/albums/v2...rx7rb20001.jpg
http://img.photobucket.com/albums/v2...rx7rb20003.jpg
http://img.photobucket.com/albums/v2...rx7rb20004.jpg
http://img.photobucket.com/albums/v2...rx7rb20005.jpg
http://img.photobucket.com/albums/v2...rx7rb20008.jpg
http://img.photobucket.com/albums/v2...rx7rb20010.jpg

R.P.M. 07-21-08 08:39 PM

I had my engine set back further than that, it was pretty much touching the firewall :)


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