sr20det vs rb25det

[nissan240sxcrazy12]

for autoX purposes only what engine would get the job done the best?i know the rbs more powerful but its also a couple hundred more lds more so is the power worth the weight or is it gonna handle like ****?

[180fan]

dunno if you want to throw off your weight balance like that man. with an sr, you're basically at 50/50 and figure an rb25'll be a 6 banger aka more weight aka there goes your weight balance aka you're not gonna handle as well which is pretty important for autocross.

[USsil80]

i would go with the sr(which i did) first 4 banger will, as said above , will give you a better weight balance... second it is easer to find upgrade parts for the sr here in america.. also just becouse of its proven on track record

[AREITU]

If oyu look at a picture of an SR, it sits very far back and up against the firewall. It's also lighter because of the aluminum block and less mass to begin with. Putting a Silvia front on would make it even lighter. RBs tend towards understeer anyway and put more mass forward into the car.

[DriftBandit]

The only thing I can see the RB doing well in a 240sx is drag racing. Where weight distrubition dosent really matter and the RB has been proven to attain very high horsepower. I would stick with the SR its an easier install, And like they said above its cheaper and parts are easier to come by.

[quiksilvia]

sr!!!!!!!!!!!!!!!!!!! w00t. if not for weight, just get it cuz of all the oem and upgrade parts available

[theronin]

pssshhhh the rb is wayyyy more jdm tyte

[bendychicken]

Here's a thought. RB30DET. It can produce very linear HP with TONS of low end TQ, if the correct turbo is matted to it. As for wieght distribution, you can just put your battery and other things in the trunk. The SR is much lighter though. I just think the RB's would be better due to linear power production. An SR, with it's spike off power, would be more apt to give you snap-over stear. Just my 2 cents.......

[theronin]

i wonder if theres a 2.4 liter 4 cylinder out there that could be turboed? that would be quite a nice powerband with quick spool... hmmm im gonna do some research, ill get back to you all.

[bendychicken]

But will the 2.4 put out over 400ft/lbs and 500hp on stock internals? All the while maintaing a very linear power curve and having outstanding long turm reliability?

[theronin]

i dunno, thats why im researching, geez man gimme some time here.

[quiksilvia]

its that time of the month for ronin, hes a lil pissy

[Bluefire]

Alright obviously the RB weighs a lot more than the SR. But on the other hand the RB is known to have more potential than the SR in the long run... now... what if you were to add some weight to the rear of an RB powered 240 so that the weight balance were 50/50.

SR 240 - less power but lower net weight and 50/50 balanceRB 240 - more power but higher net weight and 50/50 balance

Would this just mean that both cars would run equally as fast or in what aspects would one have an advantage over another....

-Bluefire

[quiksilvia]

now u just added weight-not tight, u dont want to add weight to compensate, that nullifies the purpose of a faster motor.

[Nathan]

180SX SR20-DET 1998cc I4 turbo: 559lbsSkyline GTS25t (R33) RB25-DET 2498cc I6 turbo: 622lbs

Info taken from this thread: http://www.nissaninfiniticlub....ber=2

IMO, 60 lbs. is a negligible difference, heck it can be made up just by moving the battery to the back and ditching the power steering almost.

[dareo]

RB Engine/trans weight is not all straight up on the motor. THe transmission is much beefier too. I don't see having an RB motor versus an SR as being a huge weight deal, at least on an S13. S13 could use a little more up front. S14 you may want to relocate some stuff to the back.

[Nathan]

Well, truth be told I dont know EXACTLY what is included in that weight statistic. I doubt the transmission is but 622lbs is a LOT, I would think that much weight would include a transmission too.

[dareo]

I'd estimate that weight figure to be motor and trans no crossmember. Who knows if thats dry weight, with any accessory pumps or pulleys, AC or not. The list goes on and on about what can affect the weight.

I think they are close enough to not worry about it. Leave the extreme weight concerns to chicks!

[quiksilvia]

the sr weighed in at 493lbs when scc did their swap. thats the motor with no fluids, but with the accesories on it-ac/ps/alt etc. they didnt say thats with or without the transmission, but they said the "the sr weighs....and the ka weighs..." so id say thats no transmission

[Nathan]

I dunno, I've lifted a KA out of an engine bay with just the block, intake manifold, head on it and it couldn't have been over 200lbs. I cant see how there could be over 200 extra lbs. in accessories on there. What'd they say the KA weighed in SCC?

[rico05]

I am pondering mabye a RB. The SR is getting wwaaayyy too common to be as cool/original as it was just 2-3 years ago. I live in a smaller town and there are several running around.

[Got_Nissan?]

Since the rb is and inline motor, wouldn't that also shift the weight forward? Since it's a longer block and all?

I saw a VG30 in a 240 in some jap magazine, dunno, that block is a lot shorter than an inline motor maybe that'll not shift the weight so much and be better?

Although it might only make a difference if the weight shift goes over the front axle point. If anybody knows for sure fill me in.

[Nathan]

I'm sure it would a little but I can't see that mattering all that much. I mean if it really matters then lets stop hanging intercoolers off the front of our frame rails and instead go to ducted top mounts like a WRX.

[quiksilvia]

the ka was reported at 490

[cyp]

and the debate lives on......and on and on........and on