Nissan 240SX Forums banner
1 - 20 of 41 Posts

·
Registered
Joined
·
276 Posts
Discussion Starter · #1 ·
I've read the stickies and gone to several of the links but I have yet to get a straight answer. I'm trying to find out what the potential of the different engines are. The sr20 has a huge aftermarket support so people say that it has the most potential because it has the most aftermarket support. Other people say that it tops out at a lower HP than the RB engines because of the difference in displacement. The RB engines can produce more power with the same parts because they are bigger. Both seem to make sense.
I also know that HP is basically limited to the amount of money that you want to throw at it, but staying within the realms of normal reality, every engine has a certain point that it basically tops out at.
 

·
Registered
Joined
·
5,783 Posts
well, more hp always sounds good, but there are more factors to take into consideration. like the rb for example, it is a bigger engine, supplying more hp at the onset, however, the rb is a couple hundred pounds heavier than the ka24 and the sr20 due to the addition of two cylinders, bigger block/head, etc...to say the sr and ka top out at a lower hp than the rb is a very relative statement. no engine tops out. engines can produce virtually as much power as u want if u make the correct modifications and additions. but, HP isnt everything. displacement does play a big factor, but displacement = weight. to the average joe, aftermarket support is a big factor, but if u know what ur doin u can make use of whats available. there is no real 'straight answer' to your question. for example, the 2.4L ka24de has a high displacement for a 4 banger which will supply more tourque if say a turbo is added vs an sr at the same boost. but, what if you stroker the sr to 2.4 liters of displacement. the question is very relative
 

·
Registered
Joined
·
276 Posts
Discussion Starter · #5 ·
2 questions

would it be possible/feasable to put the RB on a "diet" to make it weigh less, to the point of being similar to the weight of a SR

so would it be correct to say that the SR starts with less HP, but is easier to get more, whereas the RB starts with more HP but is a little bit more work to get more
here's a hypothetical example:
the SR starts with 200 but gets up to 400 rather easily
the RB starts with 300 but takes more to get to the 400 mark

i know that didn't really look like a question but it was
 

·
Registered
Joined
·
5,783 Posts
well....theres not much u can do to put it on a diet...the rb has a iron block and aluminum head. the iron block is gonna add a lot of weight. now i dont know if u can find a shop that could custom make an aluminum rb block but that would really save some weight. the sr20 on the other hand is aluminum block aluminum head which explains why it is the lightest of the ka24 and rb25, not to mention it has the least displacement. theres not much u can do to lighten the motor itselft. the rb25 will always be significantly heavier than the sr because of the 2 extra cylinders, bigger size, and more displacement. as for getting power out of the motors. both will react to the right modifying positively. the rb25 actually starts at 250hp and the sr20 at 205 to 250 depending on which one u get. its not harder to get more power out of the rb25, just more expensive.
 

·
Registered
Joined
·
276 Posts
Discussion Starter · #7 ·
so is there any advantage over having those two extra cylinders in the long run?
like say if i got crazy and decided to get into the big stuff and was looking to hit 1000+ HP I would assume that the RB would handle that alot easier compared to the sr20

there's got to be a reason to go with the RB engine other than to look cool saying "yeah, I've got the skyline engine..."
from what i can tell the only thing you are really gaining is a few hundred pounds.
 

·
Registered
Joined
·
5,783 Posts
well im gonna assume if u were gonna go for 1000+ HP, it would be a drag car. yea the rb would probably be best because the upped displacement will offer more low end tourqe. the sr20 could reach 1000hp, but it would take a lot of work and money and the low end tourque would be no where near what the rb would pump out at 1000+ HP.
 

·
Registered
Joined
·
276 Posts
Discussion Starter · #13 ·
ok so maybe not 1000 hp
i'm just sayin that most cars, at least the ones around here, seem to run at about 400 hp give or take. maybe even 500 for the considerably more tuned rides. I'm just curious about the bigger numbers, the 600 + range that no one ever seems to run in
 

·
Registered
Joined
·
276 Posts
Discussion Starter · #14 ·
i'm picking up on that both engines seem to put out 400 hp with just a little bit of elbow grease. but which one would go further easier i guess is what i'm trying to ask.
right now i'm looking to run in the 400 hp range, but a while down the line, when my wallet has healed, i'd like to push that number alot higher.
i'm not sure if i'm asking the right question yet...
 

·
Registered
Joined
·
5,783 Posts
bigger numbers = more money. 400hp out of a rb25 is easy. 400hp out of a sr20 is not too much harder. both engines are good to go at 400hp running stock internals...over 400hp out of a sr20 basically requires internal work. internal upgrades are very expensive on top of all the fuel and ecu upgrades that will be required. im not sure how much power stock rb internals can take.
 

·
Registered
Joined
·
276 Posts
Discussion Starter · #19 ·
alright so basically what we've boiled it down to is that the SR20 is a decent engine for right now. its for the guy who wants a cool car now and thats pretty much it. whereas the RB has a little more potential to it so you can get the right now out of it and still have room to grow.

in a nut shell, right?

i know the sr is an alloy block and therefore weighs alot less than the rb. how much would it affect the cars performance, in both speed and handling.
i know the general rule of thumb is the less weight per HP leads to higher performance levels, but is it really that much of a difference in this case at least
 
1 - 20 of 41 Posts
Top