rb20t vs rb25t power output

[sn00p]

With mild mods eg boost, exhaust, fmic, pod what power does rb20 have, and rb25 have?

If i were to buy a f/cut would it be worth spending the extra $$ on the rb25 or just save it and spend it on mods to the rb20.

This based on average f/cut price rb20t - 1.5k, rb25t - 3k.

Thanks 4 info

[Sydneykid]

Hi sn00p, if they have the same mods (eg; same turbo) there is very little difference in the max power output of a RB20DET and a RB25DET. Because of its extra capacity (25%) an RB25DET will have a fatter torque curve, come onto boost earlier (more exhaust) and have better off boost performance.

It not until you get over 400 bhp that the larger ports and valves of the RB25DET start to make some difference. My suggestion would be, if you want less than 400 bhp buy an RB20, if you want more buy an RB25.

There is an age question here as well, but a 70,000 kilometre RB20 should be just as good as a 70,000 kilometre RB25.

Hope that helps

[macka]

I agree with Sydney in a way although i dont see RB20s make the same power as the 25s with same mods....no way!

Although they keep up because of their lower weight this is where u fit in and i think an Rb20

will suit u fine and specially with the lower costs....

But hell.....SR20s Have made me piss so i personally would concentrate on working with your engine to make it stronger instead of putting in a half bodged one from another car!

[Guest Works Auto]

Originally posted by macka

I agree with Sydney in a way although i dont see RB20s make the same power as the 25s with same mods....no way!

Sorry to spoil the party but yes the rb20 can make the same power as a rb25 with the same mods.

I have proved it myself that i can make more power than most 25's with the same mods. Cooler , exhaust , Boost..

240hp@wheels on 1bar at barry's dyno and theres more left in it.

:shake: :shake: :shake: :shake: :shake: :shake:

[rev210]

The port and valve sizes on the RB20/25 heads I though were the same?

Rb20's don't make the same power for exactly the same mods. The benifit is they come in smaller/lighter cars factory and arent' a slouch of a motor.

Both are good engines, same design, more cubes - more power.

[Guest Works Auto]

I disagree totally... my mates have rb20's making 300hp at the wheels with hi flow turbo's and front mount as the only mods.

What it lacks in capacity it makes up with revs.

[whatsisname]

Each to their own. Both good engines. I personally prefer the extra 500cc capacity over extra rev's.

[rev210]

Works auto,

What revs is your mates rb20 making the power at?

The bottom end is just as strong/weak on both the Rb25 and rb20. they are both very small engines and will rev like hell.

2.4L stroker kit for the RB20, need I say more.

[MetBlue_GTST]

All i can say is with my R33 GTS-T which was COMPLETELY stock, stock cooler, turbo etc. but with a piggy back apexi F-Manage ecu and EBC running 0.85bar i got 252rwhp on Barries dyno...

[Gradenko]

Works Auto, I find it cute that a small group of anti-RB25 biggots have popped up in order defend the already well respected RB20 whenever its ability is questioned, but honestly, we're all on the same team here. Go Nissan!

BTW, rb25 with cooler + exh + boost = check my sig (also at barries dyno)

[Guest Works Auto]

Originally posted by MetBlue_GTST

All i can say is with my R33 GTS-T which was COMPLETELY stock, stock cooler, turbo etc. but with a piggy back apexi F-Manage ecu and EBC running 0.85bar i got 252rwhp on Barries dyno...

Just outta curiosity.... what is an Apexi F-Manage ??? ive never heard of one but correct me if im wrong. I know theres a GReddy E-Manage but F-Manage.

[MM2death]

I got 203hp out of my RB20 @ 12psi with stock cooler.

[GILTY]

I got 198.8 RWHP with stock turbo, stock mgmt and stock cooler.

On Cramer's Dyno in Toowoomba (QLD).

I was quite happy with that!

Both the RB20 and RB25 are great engines that sound PHAT!

Any questions?

[Neil]

snOOp,,,,With mild mods as you have stated the RB25 would be a better motor,,,,but if you want more power later on the RB20 gotta be a better base to start with,,,,lower Compression means a better Turboed Motor.

Neil.

[MrMayhem]

Wow angry posts sweet..... everyones taking it personal very objective

Hey Snoop

My advice would be consider it a bang for buck comparison like i think you are already, assuming you can get either cut at your stated prices, a Rb20det would poo on a RB25det with teh spare $1500 dropped on the baby 2L. Its simple bang for buck

Now looking at the previous posts

"Macka"

"But hell.....SR20s Have made me piss so i personally would concentrate on working with your engine to make it stronger instead of putting in a half bodged one from another car!"

Too true that dirty lil 4 potter in a light car wrecks hell with equal mods

"Rev210"

"Rb20's don't make the same power for exactly the same mods. The benifit is they come in smaller/lighter cars factory and arent' a slouch of a motor."

You remarked how quick lag wags r31 silly is in another post 13.01.... its weighs in at 1390kg... much like a r33, Its a R32 RB20det a 3" a truck cooler and a high flow t3..... 290rwhp

"The bottom end is just as strong/weak on both the Rb25 and rb20. they are both very small engines and will rev like hell."

This isnt so, have you ever put a 20 rod next to a 25 one?

Also it seems the high compression ratio combined with weak pistons crack RB25det ring lands when they start breaking 300rwhp no?

"Both are good engines, same design, more cubes - more power"

Too True!!!!

When all things are equal

Dont waste your time rebuilding 25s then donate the head to a 3L

"MetBlue_GTST"

Completely stock making 252rwhp is extremely impressive never seen a stocker put down that power more like 170-180rwhp, cant see how its breathing through such a small exhaust

"Gradenko"

"Works Auto, I find it cute that a small group of anti-RB25 biggots have popped up in order defend the already well respected RB20 whenever its ability is questioned, but honestly, we're all on the same team here. Go Nissan!"

Paranoid...... lol but yeah too many emotional incites cant really go wrong with most nissan gear

"ndr"

snOOp,,,,With mild mods as you have stated the RB25 would be a better motor,,,,but if you want more power later on the RB20 gotta be a better base to start with,,,,lower Compression means a better Turboed Motor."

True reliable stock internals that can rev...... just add boost

If Ive annoyed anyone its not my intention these are my opinions

[Jay95R33]

Bang for buck, and if you where prepared to send $3k on the motor, I'd go the RB20 for $1.5k and then spend the other $1.5k on mods.

Think about it. Stock RB25, or a RB20 with $1.5k spent on it !!!

[rev210]

Mr Mayhem,

Cracking ring land has nothing to do with revs or RODs (I have yet to hear of a bent or broken rod on either motor although I'm sure it has happened). It's poor mixtures and timing that kill.

300rwhp? geez mate there are quite a few RB25s with over 400rwhp on stock internals, they don't crack ring land because the tuning is performed by non-knuckleheads. You can crack ring land easy as pie on either motor if you try hard enough.

Therefore the so-called inherent weekness of the RB25 is bull$&*%, don't believe a word of it mate.

On the bang for buck stakes: $1500 won't buy you much in any case. After spending that much the power output might be equal but, I'd has at a guess the RB25DET will give you a fair bit more torque. 'Torque wins races' as they say.

If I crack a 12 next time I'm down the plex I think we can put this argument to sleep, Shall we agree on that?

[Doctor]

Everyone please accept the fact that each engine has its own advantages and disavantages. One will have less lag, one will not rev as hard yada yada yada. Theres no need to argue the fact.

[MrMayhem]

......... dont recall saying revs or rods breaks lands... nope I didnt

Yep torque is what turns the treads best not wasting money on that rb25det and invest in the 3L

but as for a 12 on stock cooler stock turbo no funny business .... yep that would definately impress in any case no matter how you look at it!

[R31Nismoid]

Hey...

fairly passionate poeple here huh!

Well i've had both motors.

I had an R31 with a RED TOP ECCS with a 3" Turb's back.

wasn't a bad engine at all. It loved to rev that's for sure but the turbo just died in the ass about 5500.

I've just picked up an R31 GTS-R with an RB25DET in it.

It has a bigger turbo, hit's boost about 4,000 so that would make it a big one huh?

No idea what it is yet as i'm not that technically minded. And i have to say that the RB25DET is much better.

Yes this one has a Zorst/pod and i think better diff gears...

But the off bosst driving is simply better with the RB25. You don't have to boot it as much to get it going.

So personally i'd go an RB25.

They are really smooth, and the one i've got rev's just as hard as my RB20. If not better!

It's certainly more smoother ECU even though my RB20 ECU was chipped.

just thoughts.

ash