Is the RB25 a bad cornerer?

[EchoOfSilence]

Out of the research that i've done, there has always been a split: 1) yeah, rb25 = drag; ka, ca, sr= cornering, drift, etc. 2) most people with the rb say that they couldn't feel a change in handling after the rb went in. So what's the deal? (i'm oriented towards cornering and slight drift) (in an s13)

[andrave]

youre a dill.

[Phoen_x_s14]

Depends on how your suspension will be tuned and the level of racing/driving/drifting skills you have or need to improve on to pull it off drifting/fast cornering.

[BadMoJo]

Yeah pretty much...

The only motors that can Corner and Drift are the KA, SR, and CA. And the SR is the only one that can do badass drifts...

And youre right, the RB is a Drag only motor. Even if you try, the RB just will not drift...

















:tweak:

[twitchy]

why cant the RB drift?

and whats with their name game?

i heard RB= race build

but whats ka, ca, sr, etc? what do they all mean

[adey]

kekekekekekkekee...
:D
To clear things up, the guys above were making fun of you. There's no such thing (well, almost) as an engine that can't corner! It's all about the chassis, suspension and most importantly the DRIVER, when it comes to the way a car drives.
The RB25 and RB26 are just skyline (and staega, cefiro etc) engines (RB, KA, CA, SR don't mean a thing, just engine codes) while KA, CA and SR are 240 (and other trucks/cars) engines... It depends nothing (almost) on the engine what the car will do better - drag or drift.

[BadMoJo]

Yeah, its all about chassis and suspension setup... as well as driver. ;)

[Bill Roberts]

The weight difference is simply not that much to worry about..

looking at the rundown...if you want very close to the 53/47 distribution that 240's have as a stock automobile, all you need to do is:

A. Relocate the battery to the rear of the car.
B. Lose the A/C condenser and compressor/hardware.
C. Lose the Power steering.

This would account for the 70 to 120 lb. difference and the battery would shift some weight to the rear.

Actually, the SR (because of the turbo and manifold) is very close to the KA.

I have driven an RB25DET equipped 240SX with no suspention mods and battery location and it handled fine. It did not seem nose heavy at all...if anything, it corrected some slight understeer.

Now... a Small Block V8 would need some mods for sure.

[Phlip]

Originally posted by Bill Roberts

Now... a Small Block V8 would need some mods for sure. *closes that door* BAD BILL!!!
Back on topic: I got a glimpse up close of an RB up close last weekend, but we were at the dragstrip and the engine hasn't been in the car long... I can, however, from what I see visually see no reason why this car, with the proper suspension/driver, would NOT be a badass handling car... Steeles, who has an SR in his car, took it down the strip, and spent the trip home telling us that if his SR craps out, RB will be the way to go... I do agree with Bill about distributing and/or removing weight to maintain the already decent F/R distributionand proper suspension setup is absolutely necessary with any engine. I think the RB can and will surely be a good handler, properly set up, but just throw an engine at the car and you will surely have a nose-heavy pig.

[mbmbmb23]

Dont forget the biggest weight reducer you can do upfront......CF hood. Have you seen people with stock springs with CF hoods+silvia conversion faces?? Those cars run positive camber upfront and have 4WD ride stances.



-m



Originally posted by Bill Roberts
The weight difference is simply not that much to worry about..

looking at the rundown...if you want very close to the 53/47 distribution that 240's have as a stock automobile, all you need to do is:

A. Relocate the battery to the rear of the car.
B. Lose the A/C condenser and compressor/hardware.
C. Lose the Power steering.

This would account for the 70 to 120 lb. difference and the battery would shift some weight to the rear.

Actually, the SR (because of the turbo and manifold) is very close to the KA.

I have driven an RB25DET equipped 240SX with no suspention mods and battery location and it handled fine. It did not seem nose heavy at all...if anything, it corrected some slight understeer.

Now... a Small Block V8 would need some mods for sure.

[AKADriver]

Today's quick and dirty physics lesson: Polar Moment of Inertia.

What Polar Moment of Inertia means to you: if something has its weight concentrated nearer the ends, it has HIGH polar moment. If something has its weight concentrated nearer the center, it has LOW polar moment. The higher the polar moment of inertia of an object, the more difficult it is to rotate the object.

Getting a car to turn-in effectively with the least drama is all about getting it to rotate. Autocross, racing, drifting... you want your car to rotate freely.

Look at any modern front engine, RWD performance car, like an S2000 or a 350Z. Notice that the engines in these cars sit almost entirely behind the front wheels. The bulk of the weight of the car is as close to the center as possible, so that the car will rotate more easily.

Now let's look at our old friend, the S13. With any of the stock four cylinders, the engine hangs a little bit forward of the front axle centerline, but not much. It's not optimum, but it was a good design for a cheap car in 1988. Now let's replace that engine with an RB. All that space formerly occupied by lightweight nothings like the fan and fan shroud is now filled by two more cylinders mounted in an iron block. You've added more weight further out towards the ends of the car - you've added more polar moment, making it more difficult to rotate.

Now, in the real world, you're not adding MUCH polar moment, and it can be recovered by relocating the battery to someplace central like the rear seat area (ever notice that Honda and Mazda put their batteries up against the firewall? polar moment! this is why those cars handle so damn good for FF).

If you've really got your heart set on an RB, and you're not a competitive racer, don't worry about it. It won't make the car suddenly handle like a pig. You might even like the change, who knows.

[Phoen_x_s14]

/\
|| :bowdown:

[EchoOfSilence]

i understand the polar moment explanation, but the fact that most of the weight is in the tranny means that less of the weight is in the motor itself. Which means that since the tranny is centered (more or less) towards the center of the car, wouldn't it help reach 50/50?

[twitchy]

if you want a good handling car just get a McLaren F1 and *arnold voice* STHAWP WHIAANING!

[twitchy]

or one of these...

http://www.supercars.net/SDBQ?y=2004&m=Covini&o=C6W

[AKADriver]

Originally posted by EchoOfSilence
i understand the polar moment explanation, but the fact that most of the weight is in the tranny means that less of the weight is in the motor itself. Which means that since the tranny is centered (more or less) towards the center of the car, wouldn't it help reach 50/50?

Sorry to let a good thread go unchecked...

Hmmm, I don't know about the RB25DET, but the RB20DET uses the same basic FS5W71C transmission as the KA, CA, and SR. I guess the RB25DET unit is larger. Even without transmissions, though, the RB is still longer and heavier than any of the four cylinders.

The static weight distribution will not change much, but it will shift forward. You're right in that adding transmission weight doesn't tip the balance (the stock automatic is 60 pounds heavier than the stock manual and does not change the weight distribution); but there is engine weight added, and engine weight is added further to the front of the car.

I'm personally more concerned with polar moment than static weight distribution, anyway... adding transmission weight in addition to engine weight is a good thing for polar moment.