RB FAQ

[lg54]

didn't want to create a new thread about this so decided to post it here.

Im going from an rb20 to an rb25. What parts would i need that are not the same on the 20?

What modifications would i have to make? will the radiator fit the 25? will the rb20 transmission bolt on the 25?

thanks a lot.

[smoked240]

Originally Posted by lg54

didn't want to create a new thread about this so decided to post it here.

Im going from an rb20 to an rb25. What parts would i need that are not the same on the 20?

What modifications would i have to make? will the radiator fit the 25? will the rb20 transmission bolt on the 25?

thanks a lot.

Radiator will work. If you haven't already upgraded to a larger aluminum one, I would do so now. The rb20 transmission will bolt up, but I would use the rb25 one since it is a lot stronger.

[lg54]

Originally Posted by smoked240

Radiator will work. If you haven't already upgraded to a larger aluminum one, I would do so now. The rb20 transmission will bolt up, but I would use the rb25 one since it is a lot stronger.

thanks for the quick reply.

yeah, i already upgraded to an aluminum one. so basically i would just have to do the engine harness for the 25?

i am upgrading because i started drifting and want to reach around 360+ whp in order to stay competitive in my country. Rb20 is a bit sluggish and an old motor.

in what motor would be easier to achieve 360+ whp with more reliability rb25 or sr20?

[smoked240]

Originally Posted by lg54

thanks for the quick reply.

yeah, i already upgraded to an aluminum one. so basically i would just have to do the engine harness for the 25?

i am upgrading because i started drifting and want to reach around 360+ whp in order to stay competitive in my country. Rb20 is a bit sluggish and an old motor.

in what motor would be easier to achieve 360+ whp with more reliability rb25 or sr20?

Pretty much just the engine harness. I am not sure if the driveshaft for the rb20 will work. I believe the Rb25 tranny is slightly longer. Not positive though.
The mount kit should work still.

Honestly, I would choose the rb25. But that is because I absolutely hate Sr20's. I would choose a Ka-t over an sr20 any day.

But, the rb25 and sr20 can achieve 360+ whp easily. I'm not sure what the sr20 internals are rated at but you would be fine with stock internals on the rb25. Sr20's might need to be up'd to forged(not an sr freak).

With a basically stock Rb25 with FMIC, Greddy style intake, AFPR, walbro fuel pump and a proper tune I could see close to 300 hp if not more on 9-10lbs of boost. The rb turbo can handle that, but no more.

If you plan to run anymore boost I would recommend a new turbo. I have been looking at the Hyper gear turbo's since they are a 100% drop in for the Rb25det so you won't need to make piping work, and they range from 450hp-around 800hp.

For now I am going to pick up a hyper gear turbo and run low boost.
Also to remember that the Maf can only read up to 310hp-340hp(not 100% sure but close to this) So either a new maf or standalone would be needed.

To wrap it up, you don't need 360hp+ in order to stay competitive.(unless your in FD,then you will need 1000hp v8's haha.) People drift just fine with stock sr's, ka's,rb's. As long as your suspension is gone through(I assume it has been since your trying to stay more competitive).

[lg54]

Originally Posted by smoked240

Pretty much just the engine harness. I am not sure if the driveshaft for the rb20 will work. I believe the Rb25 tranny is slightly longer. Not positive though.
The mount kit should work still.

Honestly, I would choose the rb25. But that is because I absolutely hate Sr20's. I would choose a Ka-t over an sr20 any day.

But, the rb25 and sr20 can achieve 360+ whp easily. I'm not sure what the sr20 internals are rated at but you would be fine with stock internals on the rb25. Sr20's might need to be up'd to forged(not an sr freak).

With a basically stock Rb25 with FMIC, Greddy style intake, AFPR, walbro fuel pump and a proper tune I could see close to 300 hp if not more on 9-10lbs of boost. The rb turbo can handle that, but no more.

If you plan to run anymore boost I would recommend a new turbo. I have been looking at the Hyper gear turbo's since they are a 100% drop in for the Rb25det so you won't need to make piping work, and they range from 450hp-around 800hp.

For now I am going to pick up a hyper gear turbo and run low boost.
Also to remember that the Maf can only read up to 310hp-340hp(not 100% sure but close to this) So either a new maf or standalone would be needed.

To wrap it up, you don't need 360hp+ in order to stay competitive.(unless your in FD,then you will need 1000hp v8's haha.) People drift just fine with stock sr's, ka's,rb's. As long as your suspension is gone through(I assume it has been since your trying to stay more competitive).

thanks a lot for the help. Yes my suspension has been gone through, its just most of the cars i compete against have 400+ whp, you know what i mean. i don't wanna be a dyno king, just have something to stay competitive.

i have the z32 maff already and if i go rb25 ill probably end up gong stand alone (power fc).

isn;t the 25 going to mess up the weight distribution of the car,(i have a hatch) Hows does the car feel with the heavy motor up front?

i was also looking at the hyper gear turbos, they are super interesting. They are kind of expensive but i guess that it will be less expensive at the end when you do not have to buy another manifold or other pipings.

thanks for all

[dksil80]

i see that the rb25 price dropped a little bit as well as the rb20. average for the rb25 is about $2000 for the full swap and about $12-1300 for the rb20. what do you guys think? invest a little more and get the rb25? or save a little and get the rb20 and invest the rest of the money on upgrade partS? and i couldnt find this any where... whats the max hp a rb20 can push on how much boost stock??

[lg54]

the rb20 can push around 250whp on about 12 psi of boost. (thats really pushing stock turbo)

it depends on what you want the car for. but IMHO i would invest in the rb25. more aftermarket support and around stock it can reach around 280-300 hp. thats just my opinion.

[dksil80]

mmmmm icic.. im savin up for a s13 hatch shell right now.. and i was thinking rb20 and as i was shopping i noticed the price dropped for the rb series. thought rb25 would be like 3500.. lol..i guess im wanting to push enough to beat my friends acura tl six speed.. hahaha my is300 5speed manual cant beat it. lol

[singlecamslam]

I'm sure this has been covered, whats safe boost on stock ecu and tune with stock everything.

[dksil80]

well.. like i said.. i couldnt find it.. please do share if you know the information that im looking for.. instead of just telling me that this topic has been covered.. im really wanting to know lol

thanks

[smoked240]

Originally Posted by singlecamslam

I'm sure this has been covered, whats safe boost on stock ecu and tune with stock everything.

For stock everything and stock turbo I would stay at 10lbs. Factory set is like 5-7lbs. You could push it more but you have a chance of blowing the turbo. There has been people who pushed 14lbs out of there stock turbo and had no problems, but I wouldn't trust it over 10. Also if i'm not mistaken, the ecu cut is just above 14lbs. I have accidently hit 1bar(it's like 14.25lbs) with my rb25 and the engine just cuts out. Could be fuel cut also.

Honestly the rb25 doesn't weigh much more then the rb20, I think it's like 75lbs+. I would go rb25 since the rb20 is outdated and harder to find parts for.

I think the Journal bearing hyper gear is a good deal. For the 450hp it's like $1500. I would love the BB one but I can settle for the journal. I planned to pick one up since I don't really want to buy a new turbo outlet. My skyo one was enough.

[dksil80]

thnks smoked! you pretty much answered all my questions! yeah.. i dont think i would go over 10psi until i do some upgrades.. and i was also worried about the rb20 parts being so rare. even if i do spend less and try to upgrade some parts, it will be hella hard to find parts for it. the rb25 neo is still freakin pricey.. but the 1st gen is ok price. i just need to save.. i spent to much on my is300. thinking i was gonna do a 2jz swap.. but i ended up finding a really nice 240 shell and changed my mind about the 2jz wanna keep my is300 as daily and start a project lol thanks smoked240 again

[smoked240]

Originally Posted by dksil80

thnks smoked! you pretty much answered all my questions! yeah.. i dont think i would go over 10psi until i do some upgrades.. and i was also worried about the rb20 parts being so rare. even if i do spend less and try to upgrade some parts, it will be hella hard to find parts for it. the rb25 neo is still freakin pricey.. but the 1st gen is ok price. i just need to save.. i spent to much on my is300. thinking i was gonna do a 2jz swap.. but i ended up finding a really nice 240 shell and changed my mind about the 2jz wanna keep my is300 as daily and start a project lol thanks smoked240 again

No problem man. I would recommend either the S2 rb25det or the neo. The S1 and S2 are the same price, I think it's better to have the built in ignitor's.

I recommend Zerolift for the engine. Robert has great prices, and he's a great seller.

[dksil80]

m guessing s1 and s2 would be the series of the engine.. i know the neo is that latest version. if im guessing right s1 is without the variable timing control and s2 is with it?

[GSXRJJordan]

Negative, all RB25's have VTC (variable cam timing on the intake cam). S2 motors (including Neo motors) have different coilpacks and Neo's have slightly different turbos, as well as different ECU's and slightly different wiring. They're all close enough.

[smoked240]

Originally Posted by GSXRJJordan

Negative, all RB25's have VTC (variable cam timing on the intake cam). S2 motors (including Neo motors) have different coilpacks and Neo's have slightly different turbos, as well as different ECU's and slightly different wiring. They're all close enough.

This.

I really like the S2 for having there own ignitor's. Also, I am not sure but don't the S1 and S2 turbo's differ slightly? Or are they the same?

[Zacho]

Originally Posted by smoked240

This.

I really like the S2 for having there own ignitor's. Also, I am not sure but don't the S1 and S2 turbo's differ slightly? Or are they the same?

You mean S1 having its own

Yes they are slightly different.

[GSXRJJordan]

What he means is the S2 coilpacks don't need the separate igniter. I don't see the big deal, the igniter is the same as Z32s so they're cheap, and it's easy to rewire to throw it inside the car.

I built my S1 and have built customers S2's and harnesses for Neo's, I don't see enough being better to justify the cost increase. You're going to replace the turbo if you're serious anyway, and the igniter is a virtual non-issue. What, you want the cute Neo valve cover?

[smoked240]

Originally Posted by Zacho

You mean S1 having its own

Yes they are slightly different.

No.

The S1 only has one. The S2 has one for each coilpack. Is what I meant.

[singlecamslam]

Originally Posted by smoked240

For stock everything and stock turbo I would stay at 10lbs. Factory set is like 5-7lbs. You could push it more but you have a chance of blowing the turbo. There has been people who pushed 14lbs out of there stock turbo and had no problems, but I wouldn't trust it over 10. Also if i'm not mistaken, the ecu cut is just above 14lbs. I have accidently hit 1bar(it's like 14.25lbs) with my rb25 and the engine just cuts out. Could be fuel cut also.

Honestly the rb25 doesn't weigh much more then the rb20, I think it's like 75lbs+. I would go rb25 since the rb20 is outdated and harder to find parts for.

I think the Journal bearing hyper gear is a good deal. For the 450hp it's like $1500. I would love the BB one but I can settle for the journal. I planned to pick one up since I don't really want to buy a new turbo outlet. My skyo one was enough.

And we're still talking about a stock ecu with stock settings right? I'm thinking of putting an rb20 wastegate and calling it a day. its all stock with bolt ons.

[smoked240]

Originally Posted by singlecamslam

And we're still talking about a stock ecu with stock settings right? I'm thinking of putting an rb20 wastegate and calling it a day. its all stock with bolt ons.

Yup. Your rb25 wastegate will work just fine, just get a boost controller. But I would keep it around 10lbs.

[dksil80]

then i guess i will just buy s1. cheaper.. plus if there is not much big difference..

[eklips3]

Originally Posted by dksil80

then i guess i will just buy s1. cheaper.. plus if there is not much big difference..

plus with the series 1 rb25 you can use rb20 maf , coilpacks and ignitor chip.
they all they same

[smoked240]

Originally Posted by eklips3

plus with the series 1 rb25 you can use rb20 maf , coilpacks and ignitor chip.
they all they same

That is true. It does make things easier.

If I have any problems with my Coilpacks I am just going to order a set of Spitfire anyways.

It was some work tracking down my Maf for the S2 but I got a great deal on it.

[ChadMcGarity]

I have looked through this post almost inside and out, just wondering if anyone has any guides, and great PDFs to help me with my 97 Kouki to Rb25det S1 swap.

Also quick question, I am running a m24 ar .60 HKS turbo slightly biggar and stronger then the stock. What would be the boost rating for a turbo like this? Ei: 10 psi = 250 hp type thing?

Any help and suggestions would be awesome. And if anyone has extra parts PM me!!

[GSXRJJordan]

^^^ Chad, what part of the swap are you having trouble with? Wiring?

You should be able to run the HKS turbo up to 10psi or so without any problems, you'll run out of MAF/injector shortly after that I think.

[nissanguy11]

the rb20 and rb25 oil pan are the same correct?

[socal.s13]

Ok so im in the market for a RB swap into my coupe, i live in socal and would like a good that can do this swap with a reasonable price. If any of u do swaps or know of a good place please send me the info.

[eklips3]

Originally Posted by nissanguy11

the rb20 and rb25 oil pan are the same correct?

yessur

msglngth

[nissanguy11]

just double checking.

my rb20 oil pan cracked and a buddy of mine sent me a 25 oil pan. I thought they worked, I was just double checking.