Which Would You Choose

[CruiseLiner]

1jz is deffinatly able to make more power with the stock internals over the Rb25, that goes without saying, however the Rb25 would be a much simpler install then the 1jz and the $600 you would save coulld then be spent elswhere to improve the 25 and make it a much better package over all.

<{POST_SNAPBACK}>

what would $600 get you to make it "a much better package"?

$600 aint stuff all in the grand scheme of things, and the 1jz is perfect once u wack on a big single turbo and neccessary extras and they will rip a rb25 to bits

stuff the sr20, u have very valid points Snuffle and i'd go a stock 6 cylinder and its still going to last with 300rwkw easily

still need larger injectors, upgraded ecu, single turbo conversion, ext wastegate, fuel system etc etc etc, but the 1jz is a much safer and stronger way to get there.

good luck

Brad

[benl1981]

The car came out with an SR20 in it!!! Makes it easier..the Sr is a shorter motor. Run stock internals and better turbo, powerfc nd youll be set..

I think you can do better if you get an S14 or S13 front cut. Wack it in. You could make about 200rwkw on stock internals??

If you blow it spend $1k on another motor.

I dont believe the Sr20s are any more expensive than an Rb25.

If you really want the grunt - go the Rb25...

[copycutter]

The car came out with an SR20 in it!!!  Makes it easier..the Sr is a shorter motor.  Run stock internals and better turbo, powerfc nd youll be set..

I think you can do better if you get an S14 or S13 front cut.  Wack it in. You could make about 200rwkw on stock internals??

If you blow it spend $1k on another motor.

I dont believe the Sr20s are any more expensive than an Rb25.

If you really want the grunt - go the Rb25...

<{POST_SNAPBACK}>

Mate, first of all the question was about rb25 and 1jz ONLY. I understand that the sr20 is an incredible motor for what it is, but at the end of the day it simply cannot compete with engines that were DESIGNED to outpower and outperform them, albeit in a much heavier and arguably less sporty chassis (ie soarer, r33 skyline).

Having said this, he mentioned chasing a car that has a reliable and usable 300rwkw. Using the words daily driver, its obvious that a 300rwkw 6-cyl will be infinitely more usable for driving, without anywhere near the same sort of lag.

Don't get me wrong, the 4-bangers are great - me and my mate both had 200rwkw ca18's, but my mate now has a 1jz in his 180, and i have an rb25 in mine, and i can guarantee you that they drive waaay smoother, because they're so stock.

We've also got 2 other mates - one with an 180 and one with s15, and the 180 is on its 3rd sr20, the s15 is now on its 2nd engine. Both cars were making in excess of 250-260rwkw. The s15 was using nitrous and a massive turbonetics turbo, and made closer to 300rwkw, before lifting the head off his block and warping the head-gasket etc. The point is, since my mate and i didnt have sr's it was never gonna be worth it to buy one and build it up, and the stock sr20 just ain't reliable enough to work well above those power levels.

All the boys who wave the sr flag aren't wrong, because they have such popularity and aftermarket support, but have also rarely driven anything better.

[benl1981]

Didnt see the 300rwkw buried down in the thread - fair enuf, he needs the 6cyl.

So tuna - what is the comparison betweenthe 1J and RB25 in these 2 180s?

[copycutter]

They are both awesome man. Totally different engine design though.. The 1jz makes boost a little later in the rev range (cos 2 turbos, as opposed to one smaller one), but it also revs harder. Both are just begging for the gt30r's we're putting on eventually

His car and mine are both pretty much even on the roll, but they arent quite finished yet, cos im putting on a new plenum head soon, and he still has the stock r180 diff, whereas i have the r200. different gear ratios between the r154 and the r33 five speed make a little different.

Suffice it to say that I'm yet to see the potential unleashed from both, as the plumbing difference with my plenum will be huge, and he's got the stock dump pipes which are extremely restrictive. Im running a little more boost than him too.

Once we get these things done it will be very interesting to see though...

[snuffle_uffugus]

thanks for the input guys i would still like to hear from other peoples experiences with both motors and what kinda power this engines can punch out internally standard and what kinda power they can make with what mods and turbo. thanks for that tuna so you guys are pretty close mod for mod? i wasn't going to do the exhasut either too expensive and especially cause im going with a single it will be a waste of time.

[copycutter]

thanks for the input guys i would still like to hear from other peoples experiences with both motors and what kinda power this engines can punch out internally standard and what kinda power they can make with what mods and turbo.  thanks for that tuna so you guys are pretty close mod for mod? i wasn't going to do the exhasut either too expensive and especially cause im going with a single it will be a waste of time.

<{POST_SNAPBACK}>

Yeah bro, pretty even, but both way from finished at this point. Definetly don't bother with the dumps - aint worth it my mate said. But also dont expect to be a giant killer without that massive restriction removed - even though the 1j are supposed to make more power and torque than the 25'.

But what cruise liner said before is spot on, the 1jz will undoubtedly make more power internally stock than an rb25. If my mate wanted to be a smartass he could bolt on a t78 to his 1jz and i wouldnt be able to follow without rebuild', but we both agree that at 250-300rwkw, the torque is gonna make it hard enough to keep a car with a wheelbase as short as a 180sx on the road. :lol:

Definetely great fun though, both get strange looks from petrol heads when u drive around, especially his car

Edited January 6, 2006 by tuna_144

[mambastu]

I have a RB25DETT (pair of GTR turbos on it) which is producing 405bhp (353bhp at the rear wheels). Used to have a 330bhp CA18DET in the car and the RB is so much nicer to drive. 1 bar boost at around 3600/3750 rpm and pulls hard all the way through to the raised rev limiter at 7500rpm. Fairly mild state of tune at the moment and driveabilities excellent. Makes for a very nice and reliable road car at that sort of power level. Traction in the dry on 265/40x17 rear Toyo T1's and Nissan VLSD is reasonable. Spins the rear wheels in 1st/2nd only in the dry, 1st to 3rd in the wet/cold. The smooth power delivery really helps get the power down.

Few pictures and vids of the car on http://www.mcse100.fsnet.co.uk/The%20200SX.htm

Relatively easy to do the conversion, the wirings the worst bit. It needs much more cooling than a CA or SR. Does around 260 miles to its 60 litre tank on a long run, much less when its driven properly though

[R31Nismoid]

RB25 is on the edge around the 270rwkw, in a car that weighs fark all... thats far beyond more than enough.

with the SR making mid 200's it would be even better to drive.

Obviosuly your building a car with only a one track mind. Going fast in a straight line.

Other than that, upsetting the weight balance is going to have a negative effect on the car as a whole, it wont corner or handle anwhere near as good with a 25/1jz.

With the straight line thing in mind, what sorta Auto box are you going to be running for the drags?

[funkymonkey]

i'd go with a 1JZ, purely for its ability to rev out its full range better than an RB25. In stock form its a lot more reliable than an RB25, and keeping it internally stock you can make more power on a 1JZ than on an RB25.

And if you're building a track car of sorts, then you might as well start with a stronger base.

[mambastu]

RB25 is on the edge around the 270rwkw, in a car that weighs fark all... thats far beyond more than enough.

with the SR making mid 200's it would be even better to drive.

Obviosuly your building a car with only a one track mind. Going fast in a straight line.

Other than that, upsetting the weight balance is going to have a negative effect on the car as a whole, it wont corner or handle anwhere near as good with a 25/1jz.

With the straight line thing in mind, what sorta Auto box are you going to be running for the drags?

<{POST_SNAPBACK}>

The weight distribution point is always brought up with the RB into RS13 conversion and in reality (not theory) it makes bugger all difference to the way it drives. Mine is overall less than 70kg heavier with the RB25DETT in it than when it had the CA and some of that weight is behind the front wheels i.e heavier gearbox, dual down pipes etc. People tend to forget also that the SR is a heavier engine assembly than the CA is and so the RB swap makes even less of a difference in a later 180SX.

We've found in the UK that a standard CA'd RS13 has a 51/49 FR split. With the RB25 the split goes to 53/47.....around the same as a standard S14 I believe. How does that compare to a R32/R33 GTS-T out of interest ?

I use mine mainly on road but I have done a trackday at Brands Hatch in it with the GTROC guys and it seemed to handle better than a Ferrari 355 that was circulating on the day and I've been told they're pretty trackable in standard form. Its fairly well developed suspension-wise with coilovers and castor/camber/toe corrected to get the best out of it. It could do with some chassis stiffening really. The RS13 shell isn't the stiffest around.

As regards 400bhp being enough in a RS13.......the chassis is more than capable of taking more. Traction is good but the smooth power deliverys probably helping that. I reckon it would be a bit ragged in the dry with 500 ish.

[Triskillion]

if it was going into a skyline... just the rb... unless you was 600hp... go jz...

im also thinking of a NA supra... just because there are kits out there for say 8K and it gives you garrentied 600hp...

[snuffle_uffugus]

im intending on leaving the car manual as it is going to be a daily driver as i enjoying driving manual more and a quick shift auto with stall converter is not my cup of tea. my aim is for a 11 second street driven car. I don't do any track/drift work so handling isn't that much to me but from what i heard a 6 cylinder isn't that bad handling in a s13 as there are plently of people running rb20's and if they handled that bad the conversion would rarely be done.

But i have seen plently of rb's going around town in s13's. Also if its of interest the 1jz is actually 2 inches shorter than the rb20 motor. I don't think it is going to be as much of a beast as what you guys think 270rwkw the acceleration wont be as violent in a 6cylinder as what it would be in a rebuilt 4 cylinder with that kinda power as i would need a big turbo.

What kinda turbo is needed to make 270rwkw at like 17psi on a 2.5 ltr 6 cylinder motor?

thanks for the help

cheers

snuffles

[gtst25]

No one here has mentioned a rb30????

Buy a rb30na bottom end, gtr head..... Stock Gtr turbos will bolt on then so you've got a cheap set of factory fit turbos which can supply your 270rwkw. Make sure you have gtr inlet manifold too and no bonnet clearance problems which you will most likely have with rb25 inlet manifold.

Aftermarket Gtr turbo kits are about the same price as single set ups too.

G/box?

Rb25 - look around and you will find a cheap one.

I simply wouldn't consider a toyota engine as having done a rb into commodore conversion myself that was hard enough.

Get a 50 dollar narb30 bottom end and rebuild it with stock nissan parts then you know what you've got then work from there.

The torque will be phenominal and in a light silvia nuts.

[R31Nismoid]

The weight distribution point is always brought up with the RB into RS13 conversion and in reality (not theory) it makes bugger all difference to the way it drives.  Mine is overall less than 70kg heavier with the RB25DETT in it than when it had the CA and some of that weight is behind the front wheels i.e heavier gearbox, dual down pipes etc.  People tend to forget also that the SR is a heavier engine assembly than the CA is and so the RB swap makes even less of a difference in a later 180SX.

your also forgetting gearbox weight i think there.

you really need a 25 box, and they are excepetionally hefty

[copycutter]

Surely the r33 5-speed isn't THAT hefty. It couldn't possibly weigh more than 50-75kgs, and the weight is more mid-ship weight than front weight per se, as the gearbox is located well aft of the front axles.

I think that mambastu has a better idea than most, as he is clearly involved in circuit racing, as can be seen from his website, and from the video I saw the car seems fairly well balanced following a car that's market value was like 6 times more. I doubt he would have chosen his current setup OR kept it if it handled that badly, and as snuffles says, RB conversions arent exactly as scarce as hens teeth. B)

[R31Nismoid]

put it next to an RB20 box, the weight difference bring the total to over a 100kg's extra weight easily. A car with an SR, lighter, less power...

would be faster, and far more nimble which is an overall win for any circuit racer.

Not that he has an SR anymore, but just for notes sake

[mambastu]

your also forgetting gearbox weight i think there.

you really need a 25 box, and they are excepetionally hefty

<{POST_SNAPBACK}>

No, the whole car is just under 70kgs heavier now than it used to be with the CA with T3, 460's, Z32 MAF and FMIC. Thats RB25 with RB25 gearbox. GTR manifolds/turbos, custom stainless inlet pipework, twin custom downpipes, GReddy plenum, GTR (R34) front mount IC, 550's, Z32 MAF. You can trust me on this...I weighed it before and after with a full tank of fuel and fluids to keep things constant

The gearbox is a little bit heavier but no-where near 100kgs. I have saved a little bit of weight with a slightly lighter front bumper assembly, 1 piece prop and the wheels are around 1 to 2kg lighter per corner. However I've also fitted larger front and rear disks and GTS-T calipers on the rear which would have offset some of the weight advantage of the wheels.

Edited January 7, 2006 by mambastu

[mambastu]

I think that mambastu has a better idea than most, as he is clearly involved in circuit racing, as can be seen from his website, and from the video I saw the car seems fairly well balanced following a car that's market value was like 6 times more. I doubt he would have chosen his current setup OR kept it if it handled that badly, and as snuffles says, RB conversions arent exactly as scarce as hens teeth. B)

<{POST_SNAPBACK}>

I wish I was involved in circuit racing but my budget limits me to the occasional trackday. Only did the one last year but hopefully get a couple more in this year.

You can see from the video that the turn-in is great on track and the car is nice and balanced, not a chronic understeerer as you might think with the six up front. The cars my daily roadcar so I'm keeping it strictly road friendly - no stripping it out or silly hard spring rates.

[Savage Bliss]

1JZ for sure... Love the RB, but really anything from the Toyota range is bulletproof!

I'm mean the fact they were using 3S GTE's in the Supra touring cars up untill recently just goes to show.

BASTARDS!