(a mini skip is a bin)

Teh Rb30 cannt be beat!! But seriously has anyone seen any decent power out of a Rb25/30 conversion what cfm does a 25 head flow. I haven't seen a real powerful one so far, they are all 26 headed. cheers darren Some original photos have not been recovered yet.

Quote: Originally Posted by Jet R31 Teh Rb30 cannt be beat!! But seriously has anyone seen any decent power out of a Rb25/30 conversion what cfm does a 25 head flow. I haven't seen a real powerful one so far, they are all 26 headed. cheers darren yes i have seen one it's a stock 30 bottom end and a stock 25 head and it makes 600hp at the treads in a manual... and that is some power if u ask me.. Some original photos have not been recovered yet.

Has it run a time??, the reason i ask is the ones i see in the magazines with big power figures always run mph that the ones that make average power could run easily. Although that one with the 25/30 in the blue s14 200sx with the manual looks sorted. I keep seeing 25/30 combos choke at around 320rwkw, maybe they all have the same prob

no it has not run a time that i know off...but i will let u know by the end of the year hopefully when i have mine up and runing and then i can give a no bulls**t opion....

cool, i still think the Rb25/30 with poncams and a 3540 .82 is the BEST street setup ,even with around 320rwkw, the power under the curve is unreal, and the powerband is so wide 2800-7000rpm Cheap to if you use a good condition stock atmo bottom end cheers darren Some original photos have not been recovered yet.

my preferences would be RB20 not a chance RB25 not my cup of tee RB30 strong proven and trust worthy RB30/26 should be no.1 but for the money it costs to hybrid the two motors i dont see it beeing viable, also as iv seen 26's boared to a 28 RB26 STD engine good for 10's what els could you want

Quote: Originally Posted by Jet R31 cool, i still think the Rb25/30 with poncams and a 3540 .82 is the BEST street setup ,even with around 320rwkw, the power under the curve is unreal, and the powerband is so wide 2800-7000rpm Cheap to if you use a good condition stock atmo bottom end cheers darren so do u think that the 35/40 is the best option cause i think that it is way to small and u would want at least 1.06??? and u should be able to rev more with some poncams like up to 8,000/8,500 and with stock should see 7.5k easily.. Some original photos have not been recovered yet.

Quote: Originally Posted by 6BOOST This is from an age old myth that the 1j head flows more air than the 2j head, which it doesn't. The 1J head flows around 210-215cfm inlet stock, and the 2J flows about 235cfm inlet stock. Ported, the gap is still similar. Who knows why people do it, other than convenience if they already had a big setup on a 1j and just want more capacity. 6BOOST I heard something about the air speed being more ideal with that combination. I'm not all that clear on the theory but apparently it's the same reason some of the old school guys used to use a 186 head on a 202

Quote: Originally Posted by JBA05 so do u think that the 35/40 is the best option cause i think that it is way to small and u would want at least 1.06??? and u should be able to rev more with some poncams like up to 8,000/8,500 and with stock should see 7.5k easily.. It will rev to 8-8.5 easily , but peak power will be down to 6.5-7 depending on manifolds. I have no idea what you want out of your car, so i have no idea what turbo is the one for you, the 3540 .82 is my favourite street/strip turbo, especially on a twin cam. I HATE 1.06 housings, but everyone has a different verdict on them, i think they belong on a bigger motor- 3.5-4.0L. cheers darren

Quote: Originally Posted by VLT-025 I heard something about the air speed being more ideal with that combination. I'm not all that clear on the theory but apparently it's the same reason some of the old school guys used to use a 186 head on a 202 The reason they use the 186 head on a 202 is to increase the compression.

Generally when porting a head, you want the biggest port size, without reducing flow, so a head that flows more will make more power than the head that has lower port velocity, and without measuring them, I highly doubt the 1JZ has bigger ports with lower air speed, which is what you want, higher air speed means you hit peak port velocity sooner and power drops away. Seriously, the 1J head thing is a myth, and the only reason for doing it should be that you already have a good turbo setup on your 1J and want more capacity. We have made 398rwkw through a stock unopend RB26 with 21psi and a GT35/.82 rear, it would be my all time favourite combo. However most 26's have had the sh1t ringed out of them, and almost every one i've ever seen has had an engine rebuild or failure. I'd def stick with the 25, not to mention the 26 would cost you $3000 more to get sitting in the bay. 6BOOST

Quote: Originally Posted by Jet R31 It will rev to 8-8.5 easily , but peak power will be down to 6.5-7 depending on manifolds. I have no idea what you want out of your car, so i have no idea what turbo is the one for you, the 3540 .82 is my favourite street/strip turbo, especially on a twin cam. I HATE 1.06 housings, but everyone has a different verdict on them, i think they belong on a bigger motor- 3.5-4.0L. cheers darren well i'm going to be running a high mount stainless manifold only one of the cheapies but will be better then the stock one.. and the intake is just stock but will be upgraded to one of the front mounting throttle ones.. and the car will be a weekend/strip car... and i'm going to be running a t04z....

Quote: Originally Posted by PHS i got in a 300RWKW XR6Turbo the other day a hell of alot of lag nothing below 4000RPms Thats a load of crap. theres stuff all lag my xr6 turbo is boosting by just over 2000rpm full boost before 4000rpm (currently on 13psi) It may seam laggy but that would be the weight of the car. Stock turbo pushes these thing over 400rwkw. and y would one of these turbos be good for a rb30 if on the 4L ford it was too laggy?

The same turbo from a falcon makes full boost on an smaller rb30 by 4000rpm, let alone the BA engine, the GT35 on the 4 litres make full boost at 2300rpm, it doesn't get much more resposive for a 400rwkw car. 6BOOST

mines not stock boost so it takes alittle longer for full boost

Quote: Originally Posted by Sinister times yes, but theres no way a dirty old single overhead cam will ever compare to twin cams. IE a twin cam (not that ive driven a rb26) should be a lot smoother to drive and much better power delivery No the dirty old SOHC is no way near as Twin Cam but they are proving they make the same power of a Twin Cam A RB26 in general is not a cheap motor to run and heard they can be unreliable i stick with SOHC oldschool yet proven big HP figures

Quote: Originally Posted by Jet R31 But seriously has anyone seen any decent power out of a Rb25/30 conversion what cfm does a 25 head flow. I haven't seen a real powerful one so far, they are all 26 headed. cheers darren Thats because most people keep the standard cams or run soft arse pon cams. RB26 powered vehicles are always quick, i think its because of the wide power band they have, but if you expect to drop in a good one you will either have to rebuild or go late model R34, all the R32's seem to be letting go in the bottom end department these days if you lean on them. If cost wasn't an issue, (to build or maintenance) you would go RB26 anyday of the week.

Seen all manner of cams in RB25 heads now,ponny's, 264's and tomei 270 pro cams.... all are lame, thats why i asked about the flow figures.It's just unusual to have 3 combos that don't work theres even a rajab built Rb25/30 here, hks cams, turbonetics T76 in a R31, same thing,poor power. cheers darren

What Price range is the average person looking at to have a rb25/30 engine built? I built 1 myself and including a rebuild, the turbo 5 speed and wiring the ******* up, it was close to 4g's and im dead serious so what the cost issue?