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Rb25det Neo - Vs - 1jzgte


S15ilvia
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It probably goes against the 6 cylinder grain but a quite easy conversion for S13/14/15 is the KA24DE . USDM S13's and S14's got the KA24E and KA24DE std , no SR20DET over there .

As you'd expect they have plenty of turbo conversion bits for their KA24 cars . Being a big 4 cylinder they can make stump pulling torque without roticery revs - 600 odd cc pots . Can get everything for them in US , rods/pistons /exhaust manifolds/cams/springs etc . I'm nearly certain that the KA block/sump uses the full circle type bell housing set up just like the SR does so straight in . Also luckily our poverty pac Navara uses an 8.6 CR KA 24DE and a slightly cheaper version of the RB25DET style transmission and rear box yoke .

Don't quote me but I think the Yanks found a way to interface the SR Apexi PFC as well so injectors and MAF sensors no issue with tuneable ECU .

I personally think an RB is very long for the S series engine bay and can have cooling issues . I also have to wonder what the extra weight on the front end does for these cars .

Just a thought , cheers A .

PS - Be real nice if the GTiR inlet system could be persuaded to "fit" .

Edited by discopotato03
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I dunno if it helps but here's a link to a nissan silvia forum thread where a guy and his mate both have 180sx' but one has put a 1J in his while the other went for an RB25.

http://www.nissansilvia.com/forums/1jz-180...sx-t139528.html

Thanks for that. I read that thoroughly before i got this idea.

And for the KA engine... thannks for the info but the budget will be blown (no pun intended) just rebuilding that engine! And i dont think its as good as the engines mentioned above also. Poor americans :P

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stupid question i know.... if your gonna spend so much money on a rb25det neo, why not get an rb26dett if your looking for power?or even go an rb30 bottom end with rb25 head? still quite cheap, ive seen ready built 30/25's sell on here for under 4k

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  • 4 weeks later...
I've always wondered and now I know.

Also in reply to someone posting up there about old mate. Ask Shane how much it cost him to run 10's. A lot more than you think. Although, I think he got high 11's cheaply.

i did do it cheap in my opinion, compared to similar cars, i see guys spending 100k on a vl to run low tens on slicks when im doing it on radials with no trans brake.

i could build another car the same as i have now with a built 2j for 30 grand.

having buddies with RBs, and dollar for dollar i reckon the JZ's are easier and safer to extract power from.

i am pulling my stock engine out now and putting a built engine in in search for mid nines. i could have run a nine on this engine with out a problem given cooler weather.

just for those that dont know.

standard head, standard bottom end, standard plenum and TB, Garret T51R, 3.5 inh full exhaust, 1000cc injectors, microtech, 50 shot of gas, built toyota trans(no transbrake) standard cressida shell, pretty standard pedders suspension. the engine had 190,000 k's on it, i bought half cut with 94000 on it 5 years ago.

35 psi of boost on MT drag radials 255/50/16 and run a PB of 10.17 et at 137 mph.

to put that into perspective, 3440 pounds and that trap speed work out the power. and the great thing is the car has been running tens for a year and a half, i've been making over 450 horsepower at the tyres for over 2 years, the car gets street driven regularly and driven long distances and i havent had an issue.

in my opinion tyhe JZ's are a stronger engine, 35 psi on factory rods, over 30 psi for 1 year and adam can attest i race it alot.

shane :D

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everyone knows that 1jz and 2jz eat the shit outa rb motors. but no one will admit it if they own a skyline *iownone2*.. stock internals and that amount of boost, yet alone the price tag for a cut/engine package vs rb cut/engine package.... its not rocket science or is it :S

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after finding out howmuch my mate paid for his 1j front cut i would say go the 1j. my mate got a front cut for $1400. by the time you buy a rb25 front cut you are looking at close to $4000. so with the 1j you can buy a front cut and aftermarket ecu and get it all bolted in and still come in well under the cost of doing the rb25 conversion.

i'm looking at doing a 1j conversion into a vb commodore (since a vb commodore weighs about the same (or less) as a silvia, and has a nice big engine bay. i just want to do something different, and also want to see the look on import owners faces when i leave them for dead (as the body is going to stay in its current state - factory paint job, 15" wheels, and rust holes at the bottom of the front doors).

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finsh the thread....

you were after bang for your buck.....

rb25det NEO without a doubt, its not just the motor, its the whole package. like most people have mentioned...once you smash boxes, what you gonna do with a toyota box? Aftermarket parts for a 25 are also readily avaliable, there are so many around. Simple concept basically made to be put into any nissan. good all round motors...1j's are great, fantastic infact...just not bang for your buck material.

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finsh the thread....

you were after bang for your buck.....

rb25det NEO without a doubt, its not just the motor, its the whole package. like most people have mentioned...once you smash boxes, what you gonna do with a toyota box? Aftermarket parts for a 25 are also readily avaliable, there are so many around. Simple concept basically made to be put into any nissan. good all round motors...1j's are great, fantastic infact...just not bang for your buck material.

i have never heard of a r154 break. i know of several running around the 450rwhp mark and have done for years with no issues

W57 and W58 boxes never came behind 1j's so i am intrigued as to this gearbox issue that keep being brought up.

and wasnt the thread about the engine 1j vs rb 25, i cant see anywhere in the thread title that says which gearbox to use.

Edited by 1JZ.747
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i did do it cheap in my opinion, compared to similar cars, i see guys spending 100k on a vl to run low tens on slicks when im doing it on radials with no trans brake.

i could build another car the same as i have now with a built 2j for 30 grand.

having buddies with RBs, and dollar for dollar i reckon the JZ's are easier and safer to extract power from.

i am pulling my stock engine out now and putting a built engine in in search for mid nines. i could have run a nine on this engine with out a problem given cooler weather.

just for those that dont know.

standard head, standard bottom end, standard plenum and TB, Garret T51R, 3.5 inh full exhaust, 1000cc injectors, microtech, 50 shot of gas, built toyota trans(no transbrake) standard cressida shell, pretty standard pedders suspension. the engine had 190,000 k's on it, i bought half cut with 94000 on it 5 years ago.

35 psi of boost on MT drag radials 255/50/16 and run a PB of 10.17 et at 137 mph.

to put that into perspective, 3440 pounds and that trap speed work out the power. and the great thing is the car has been running tens for a year and a half, i've been making over 450 horsepower at the tyres for over 2 years, the car gets street driven regularly and driven long distances and i havent had an issue.

in my opinion tyhe JZ's are a stronger engine, 35 psi on factory rods, over 30 psi for 1 year and adam can attest i race it alot.

shane :)

The second time should always be cheaper. :)

I also agree that you did it fairly cheaply the first time.

Except for one guy (and no I don't know who) there is always someone who got 10's cheaper but I wouldn't look at an RB25 in a Skyline as my first option if that was my goal. Not saying it's not in the list but not number 1 without serious consideration.

With any luck someone we all know might be running 10's with an RB25 soon and without spending much at all!! ;)

How's this for a plan. Cheapass R33 S1 auto, valvebody upgrade, big turbo, giggle gas, somebody finish the list for me.

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  • 4 years later...

Bit of a blast from the past but I thought I would continue a related topic instead of starting a new one.

I've been reading around in many places and it seems the JZ family have it over the RB for max power output... but one thing I am confused about is why they are being compared? If I am wrong can someone please correct me, but I have found in several places suggestions that jz's have forged or pressure-casted pistons. Wouldn't the real comparison be the RB with forged pistons to jz's?

food for thought.

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JZ engines can make 10'000 horsepower on stock everything, even turbos and fuel pump, I don't know if anyone had mentioned this.

They are so much better ZOOM said so,

The are so much better Martin Donnon said so,

They are so much better, the Yanks think so.

.......................

  • Nope 1
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The problem with 1JZs' (and 2JZ's) has nothing to do with the engine itself, except that the turbo is on the wrong side for right hand drive. That's why the (left hand drive) yanks like their JZ's, the turbo is on the better side for them.

Pardon my ignorance. But what specific reason does it matter what side the turbo is on in relation to RH drive or LH drive?

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Righto, so here are my 2c. Please note I actually turfed my perfectly healthy RB25 for a 1JZ, and am currently in the install process to my R33.

I would like to clarify something about the 10 second passes issue noted above. Factory internal of each motor have acheived 10s, yes. Substantially factory 1JZ's have seen 10s is more so what people were trying to say. The debate I see on toyota forums regularly is how stock were your stock turbos when you ran the 10. Whether or not manifolds have been ported or if turbos themselves are steel wheeled or high flowed.

Truth is that it is absolutely nonsense to have a motor capable of so much without even needing to setup an aftermarket turbo. To note, mod for mod on the stock turbos the 1J will see similar numbers to an early model RB26 (peak power) yet with a notable amount more torque.

So, here were my options.. Persevere with my RB25 3037 setup (90% complete) and aim for 290rwkw~ or part out and for near equivalent cost setup the JZ in my car with a turn key 250rwkw~. Dollar for dollar I am down 40rwkw, quite a lot and not cheap to get back. Yet, in theory I feel the car will be faster as an all rounder anyway, and reliability will be like a factory car in comparison to the blood stained love story that would become of my RB @ that power.

Mods are not necessarily more expensive and gearboxes are a synch. A 6boob still costs what a 6boob costs and an ecu is not exact abundant for an RB25 anyway (fxxxing vct). The JZ uses map sensor and most people get out of it for an emanage blue. Gearboxes are put simply, more expensive, yet not like its hard... The one you want is called an R154, its the big gun 5 speed. You will need it with a JZ bellhousing and if you cannot find one with a JZ bellhousing you can buy the thing brand new for a couple of hundred bucks.

When I got my kit, there was a 1JZ twin turbo R154 halfcut available for $3200 + shipping. I sold my 3037 + RB25 gearbox alone for more than that. I am also doing 100% of the conversion myself so my costs are parts and materials.

I am also confident that the motor will outlive my itch for power (condition dependent), whereas my RB was feeling the stress of the 3037 before it even hit full tune.

Yet these days with the availability of highflow turbos to your desired spec, having an RB25 NEO would not be such a bad thing to work with.. However I would aim for 270rwkw or less as opposed to the token 300.

2c spent.

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