RB25 over CA long run

[Bryson]

Hi guys.. I am moderately new to the forum.. I've posted some dumb questions, some valid ones.. and learned a lot..A few months back I purchased my CA18 and have not yet begun purchasing parts.. but plan to over the next few month into summer when the swap will take place. I naggin question has been growing in my mind.. would it be worth it to sell the CA and purchase an RB25? I plan to get near 300 HP on the CA then leave it. I didn't want to be risking it by maxing everyting so I planned on injectors, fuel pump, T28,CA18/16 cams, NPR intercooler, possibly an E-manage/e-01 combo for if I ever decide to rebuild the engine for more boost.. ehh and I am sure I planned on more stuff.. the point is.. since the RB25 is around 250HP and plenty of torque stock.. and all I am trying to squeek in with the CA is around 300.. would I be better off getting the RB25 and leaving it generally stock..(beside exhaust, intake, FMIC,ect.) and waiting a while to up the boost, turbo ect.?

It seems to me that if I go with the CA and spend all the money to build it up and boost it like mad.. I will be spending near the same to put the RB25 in.. difference being that the RB will have room to grow while the CA will be starting to wane as far are durability..

It should also be noted that I was thinking of CA now.. skyline 3 or 4 years down the road.. what do you guys think?

[themadscientist]

all you expectations point towards RB25

[MikeS14240sx]

where do you live? in the US.

[themadscientist]

Japan

[Bryson]

I live in Cali, Central Valley. Smog will be fun !

[Bryson]

Also ment to throw in this little diddly, with either engine.. will I be able to push them at all with crappy ol' 91 octane California gas?

[themadscientist]

neither engine will like it, you might have to roll the initial timing back a few degrees.

[jmillheiser]

if all you can get is the 91 octane cat pee you might want to consider water or alcohol injection.

i would suggest an aquamist system. it doesn't have much impact on power but it will allow you to run more boost without detonation. water injection usually requires a CD ingntion but i dont think alcohol injection needs it.

91 is all i can get in wyoming but its also at 6000ft so detonation isn't much of an issue (of cousre my current vehicle only needs the 85 octane sludge they sell as regular unlead here)

[meggala]

if your only looking @ 300 hp the ca or even the rb20 would be worth considering it does take a bit to get a ca to 300 hp the rb 20 could do iton stock injectors with jsut a turbo upgrade fmic fuel pump etcfor 300 hp the extra monty of the rb25 is not warrantedand the higher compression of the rb 25 will not be great with the 91gasmeggala

[Dori Dori]

You already have the ca...I'd say to just keep it. Your ecpectations for HP aren't high enough to warrant needing 2 more cyl...but if you do go for an RB, a 25 would be overkill. Like meggala said, go with an RB20.

[themadscientist]

I can vouch for some of that claim. My freind had an stock RB25 and it dynoed at 300 hp on the stock turbo, my stock RB20 at 250. No matter which engine you go with a FMIC is worth the money.That was on 100 octane, full exhuast with an R pump R intercooler and boost @ .7 kilo on the 25. 100 octane, full exhuast, stainless turbo outlet, AFC and boost @ .9 kilo on the 20

[YamaOni]

Their is no replacement for displacement... The 20 is a good engine but why go through the bs to do it half a$$, I like the 20 and the 25 but if I were in the states I would not waste my time with the 20 when the 25 is not that much more in the long run.

[Bryson]

Thanks FOr the Posts guys.. I am thinkin I will go with the RB and it won't stop at 300 . I chose 300 because it seems from my reading that 300 is the point where you need to stat building the CA's internals for MORE P O W E R!, and I just didn't want to have to spend even more money. Since the RB can do more with stock internals, I am sure it won't stop at 300 with it... either way I won't make the money till summer so I have time to think about it.Thanks for all the Replies

[meggala]

hey guys now you can imagine the kind of power our aussie cars put out and night that was a great help with your dyno figures cause 180 rwkw/240rwhp is what we see on an rb25 strock with some boost around 12 psi .stock cooler and japanese exhaust. yes the rb25 make 300 hp easy and bryson if your going for thehigher power the rb 25 is better.

so just remember guy when I talk about my friend sr 20 in his 180 that made 301 rwkw/ 400hp it was useing your scale it was around 500 hp I have a friend with an gtst skyline with an hks built rb26 and that is making around 500-550 rwhp 2 1.3 bar using your figures.the stock turbo on an rb25 good for around 300 hp @ the fly wheel my rb20 makes close to 300 rwhp using your figures with an r33 turbo cooler ,exhaust and s-afc.

This comes in handy so we know when we are compareing apples with apples." No flaming intended just an explanation"meggala

[meggala]

Night you took my post the wrong way completly there was no sacasim intended. In australia with the dynos we run (dyno dynamics) we have a lot more losses and that is why I could not understand when you guys are saying 300 rwhp. @ .7 bar I would be curious as to what time your car runs down the 1/4 or actually the mph bercause that helps to gauge the differences and yes my friend car is running very similar spec to what you said he is running 2 x 2510 264 cams etc ran 12.4 @ 123 mph on bad street tyres on an unprepped track the mph tell it all it is an r33 gtst.you guys generally use dyno max dynos I think they are very different to our in the readings thats all and I was trying to get a handel on thatcheersmeggala.

[Bryson]

I think there is a person on this board, maybe it is Meggala, that would sell the block for 500 + shipping, ya? no?

Also..what kinda 0-60 do you push Night? you Megga in the Skyline? just wondering.. I know that would have a lot to do with traction, but anyways.. throw some #s please

[themadscientist]

Unfortunately, my GF threw my time slips out somewhere, or misplaced them, so I have to wait until March before I get new ones.

Night

you of course killed her and buried her in the back yard right?

[ka24de_510]

Night, do you know the weight of your car off-hand? And what width rear wheels are you running?

I think Bryson meant 0-60mph, for which 1.8 is a little too quick. At that pace, even if it took four times that long to double your speed you'd be running under 10.

You're probably thinking 60ft times.