A31 Cefiro RB20det vs. R32 Skyline RB20det

[Eikon]

I have done a pretty comprehensive search on this topic. I was wondering if anyone can elaborate a little more...

here are the comparisons that I have heard... Which one is correct?

1.) Both RB20's are identical... no power difference2.) The A31 has 10 less HP due to ECU detuning3.) The A31 has 10 less HP due to restricted intake manifold4.) The A31 has 10 less HP due to restricted exhaust system

Anybody able to confirm any one of these?

Next topic.. Mounting in an S13... Rumor has it that the A31 X-member sets the engine down about an inch and allows it to fit perfectly into the engine bay (no cutting of the hood frame). Has anyone proven this yet?

Next topic... HP potential. Assuming the internals, turbo, and other major components of the engines are the same.. I see no reason why an A31 RB20 wouldn't have the same potential HP limits as a skyline RB20.

I don't think I will ever go to a standalone engine management system, so I very interested in the ECU. Would you be able to reach the 350HP with the A31 ECU. My thinking is that upgraded fuel system, FMIC, upgraded Turbo, exhaust, and some tuning should get me there. Can anyone confirm that?

So the big question is... Should I get the A31 Cefiro clip, or the R32 Skyline clip?

[Yellow4g63]

What ever you can get your hands on with the money you have. I think it might be less hp because of the turbo maybe. Might be a diffrent trim vs the R32. Also ECU might play a big part in too. Either would be fine because it's not goin to be stock anyway.

[Ghettokracker71]

Why can't you just use the cefiro cross member and an R32 ECU? Whatever engine you get just get the other accesories?

[93RPS13]

you should ask http://www.skylinesaustralia.com they should gave you a good answer

[undertaker]

i hear the A31 ecu is only 8bit while the R32 has a 16 bit version.anyway my C33 (same as A31) RB20 pulled over 205 rwhp at about 10 psi with a panel filter and 3" exhaust, auto trans. i say go with the Cefiro clip if its the right price.

[Ghettokracker71]

Wow! Decent numbers:) I can't stand when people hate on the RB20

[Eikon]

now were talking. Thanks undertaker!

Next question... Does an 8 bit ECU harm the tunability of the engine. Can I still do the same mods to the car to get to 350hp? Or will I have to go standalone or switch to an R32 ECU later to get to that goal?

Thanks!

[93RPS13]

go EPROM!!!

[meggala]

ok a31 rb in my mind is actually beter it has bigger cams than the r32 rb20 the afm ihas a blue label not green liek the r32.

I fitted an r33 to an r32 and to an a31 mtors the a31 made a noticeable amount of power better .having said that you guys in the US need to take the motor you can get at the price you can afford.btw in my mind the sr 20 eats an rb20 every time. thats why my a31 has an sr20 not an rb 20 or rb25 because all of these options were avaliable to mecheersmeggala

[Eikon]

Meggala finally checks in! Thanks Man!

Your website it very helpful also by the way.

If Meggala says go A31... I'm going A31.

The problem is Meggala really says go SR20. Nah... too many SR20's... better stick with the RB20. I like it better.

Anyhow.. thanks alot everybody. Especially the boys from Aus, and NZ who have first hand experience with these engines.

Still wondering if the Cefiro ECU (8 bit) will hamper my efforts to hit 350hp?

Meggala.... What do you think of putting RB26 cams in the RB20? I hear that's a great upgrade!

laterEikon

[meggala]

I wouldnt do it if you get an a31 motor it will have bigger cams than gtr cams any way as they are 248o as opposed to 240o also the silver top r31motor is the same as the a31 look for the blue air flow metermeggala

[undertaker]

The problem is Meggala really says go SR20. Nah... too many SR20's... better stick with the RB20. I like it better.

an SR might be better but of all the motors I have the RB20 is one of the best sounding. An SR sounds cool in its own way but not like the RB, just one of its many virtues

the A31 ECU is the same generation as the CA18 ECU so I don't see a problem with tunability. really interesting to hear they have bigger cams than the R32 :ylsuper

[PROJECTRB240SX]

I CAN SELL YOU MY R32 RB20DET COMPUTER ONCE I GET MY MICROTECH......IF YOU ARE REALLY WORRIED ABOUT IT.

[Yellow4g63]

I CAN SELL YOU MY R32 RB20DET COMPUTER ONCE I GET MY MICROTECH......IF YOU ARE REALLY WORRIED ABOUT IT.

Which one are you geting? LT12S? or the LT8S?

[PROJECTRB240SX]

LT8S.... I JUST WANT TO GET MY CAR RUNNING RIGHT, I DON'T REALLY HAVE ANY MORE PLANS FOR BIG POWER WITH THIS CAR.

[meggala]

projectrb240sx are you getting the microtech from a local supplier. casue I woudl only buy a standalone from a place that can tunig it for me. on other draw back with them is the gas limage sux other wise they are a good ecucheers

[93RPS13]

meggala why dont your tune with EPROM burner

[meggala]

93prs13 I do tune with a rom burner both my r32 and the sr20.well actually I dont tune I have a good friend with a dyno who does all my tuning witha rom burner. wouldnt go any other way

[Yellow4g63]

Hey meggala are the RB20 redtop injectors the same as the silvertops?

[meggala]

from what I know.the silver top ones are red.cheers

[skillzilla]

I found out I infact do have an A31 RB20 (from the blue MAF sticker), although it is a 5 speed. I thought all A31's came auto?

Anyways, Im stoked to hear about the beefier cams, thats a plus side. Now Im just thinking the previous owner switched it to 5-speed, which means he drifted or raced his A31, and prolly killed the engine. Lets hope not. I cleaned up the cylinders/pistons/valves, put in a 1.2 metal head gasket, and ARP head studs, so I should be fine up top. I also inspected the rod bearings crank, everything was a-ok.

[meggala]

dotn stress if is an ex drifter alot of them look after their cars and the chances ar eyou probably scored a decent clutchmeggala

[skillzilla]

The clutch was hum-drum organic ghetto disc, nothing fancy. I changed it out for a stage 3 Spec, so thats good. One more thing, are the 270cc stock injectors the same on the A31? Are they really good for 300hp? (I am running GReddy Emanage/E-01 and a Walbro 255, prolly an adj. FPR later)

PS, youre site rox, I went there countless times while researching for my swap.

[meggala]

they are the same as the other rb20 det ones as long as they are red yeah good for close to 300 hp @ the fly wheel you can even get more if you up the rail pressure a bit. you should swap to a z32 maf if your goign that hi it really helps with tuningcheers

[PROJECTRB240SX]

I'M ACTUALLY ORDERING IT FROM GTR SHOP AND I'M GOING TO AVE MY FRIENDS AT FUELED PERFORMANCE INSTALL AND TUNE IT FOR ME.

[goofynick6]

So how can I tell if I have an A31 RB20 or an R32? I'm curious about this now.

Here is a picture of my MAF (which has since been upgraded to a Z32 unit)

http://i12.ebayimg.com/02/i/01/bd/ee/70_1_b.JPG

...and my ecu has blue on the sticker and says "23" as the main number.

Thanks,Nick

[meggala]

yep yours is an a31 motor thats the maf the r32 ones are green like this.cheers

[PROJECTRB240SX]

MY RB20DET HAS A BLUE STICKER AND IT CAME OUT OF A SKYLINE.

[Yellow4g63]

So how can I tell if I have an A31 RB20 or an R32? I'm curious about this now.

Here is a picture of my MAF (which has since been upgraded to a Z32 unit)

http://i12.ebayimg.com/02/i/01/bd/ee/70_1_b.JPG

...and my ecu has blue on the sticker and says "23" as the main number.

Thanks,Nick

The Ecu I bought of EBay said 23 on it too.

[dareo]

I've read that the cefiro crossmember is more desired to swap into the US 240sx, it seems to fit better. But I just used tophat mounts and the KA crossmember, it fits perfect.