Cefiro Engine Conversion - Which One?

[CAE]

Hi guys,

I have a A31 Manual cefiro lined up. Its non turbo and im thinking of doing either a RB26 or RB25 conversion.

I know the RB25 conversion is pretty straight forward and the RB26 has a fair bit of work involved. As i will be doing the conversion myself, i just wanted to know if its worth doing the 26 conversion or its better to get the 25 and spend the balance on mods and make it go harder than the 26?

Thanks.

[daisu]

Hi guys,

I have a A31 Manual cefiro lined up. Its non turbo and im thinking of doing either a RB26 or RB25 conversion.

I know the RB25 conversion is pretty straight forward and the RB26 has a fair bit of work involved. As i will be doing the conversion myself, i just wanted to know if its worth doing the 26 conversion or its better to get the 25 and spend the balance on mods and make it go harder than the 26?

Thanks.

I'd say buy an RB30 (you can pick them up for free these days) and then spend the balance making it go harder. There is a whole section of this forum devoted to doing twin cam conversions to RB30 bottom ends using the RB25 and 26 heads.

It really depends how much work you want to do, what work you are doing yourself (as opposed to what work you will be getting done by a workshop), what your balance is and what your end goal is.

[brada31ke70]

i brought a 26 rear wheel half cut, did the coversion myself, just run a big end bearing, not happy, either selling it as is or doing a cheap 30 now with the 26 head. looking back on it, i would maybe be thinking about a 25 neo, alot newer and i hear they are go quite well, also get the good gear box with it. rebuilding is alot more expensive than outlaying a bit more to start with, and it is a bit dissapointing when it all goes bang. but on the other hand a 25 is no 26. good luck.

[Mr Eps]

hi

i rarely visit the cefiro forum anymore cos i cbf

but

26 conversions into the cefiro i think is unnecessary, yeah, you may go hard but it also makes the car too powerful for it's chassis and body

the structure of the car and the weight balance is not meant to have that much power fed solely thru the rear wheels

i'm sure i'll get flamed for having this view but stfu i've had a ceffy longer than any of you so bite me.

as for 25 conversions, the 25 is slightly heavier than the 20, and is a further advanced engine, it's a cheaper conversion than the 26 aswell..

i think that SR20 would be a good option for a complete engine swap.. they hammer back into the firewall of the cefiro giving great centre of weight distribution, they're light, alloy head, etc etc

but all views aside, my experience and opinion is this...

i have a cefiro RB20de... but... i bolted the turbo parts on from a skyline, full conversion from turbo to injectors to coilpacks ECU etc

the reason i like this, is because the car retains it's original engine, it's a high compression turbo, meaning it hits boost at about 2000rpm.. it retains the free revving aspect too which makes it sound awesome too.. i get all this advantage but i also retain the original intended motor, meaning weight distribution retains the same keeping the car as itself nice and balanced... plus it's unique!

oh did i mention it also hammers RB25's, this is including R34's.. haha

so yeah.. i guess in short, when considering engine conversions.. don't always pick what "goes hardest"... remember, your car is a CAR and has to work as a complete UNIT. not just wheels and a motor.

[carter]

from personally owning a cefiro with an rb25 id recommend going that route, alot of it bolts straight up, my 25 makes same power with less boost as the 20 did, with shiteloads more torque, simple upgrades n i could hav 300-350hp reliably, mine cost me 3500 in, thats including parts that needed to be replaced n labour which i was very well looked after with hehe. heres a pic of how neat mine is.

[WHITE R32]

man that looks neat looks like whoever did you conversion knew their shit

[daisu]

hi

i rarely visit the cefiro forum anymore cos i cbf

but

26 conversions into the cefiro i think is unnecessary, yeah, you may go hard but it also makes the car too powerful for it's chassis and body

the structure of the car and the weight balance is not meant to have that much power fed solely thru the rear wheels

i'm sure i'll get flamed for having this view but stfu i've had a ceffy longer than any of you so bite me.

as for 25 conversions, the 25 is slightly heavier than the 20, and is a further advanced engine, it's a cheaper conversion than the 26 aswell..

i think that SR20 would be a good option for a complete engine swap.. they hammer back into the firewall of the cefiro giving great centre of weight distribution, they're light, alloy head, etc etc

but all views aside, my experience and opinion is this...

i have a cefiro RB20de... but... i bolted the turbo parts on from a skyline, full conversion from turbo to injectors to coilpacks ECU etc

the reason i like this, is because the car retains it's original engine, it's a high compression turbo, meaning it hits boost at about 2000rpm.. it retains the free revving aspect too which makes it sound awesome too.. i get all this advantage but i also retain the original intended motor, meaning weight distribution retains the same keeping the car as itself nice and balanced... plus it's unique!

oh did i mention it also hammers RB25's, this is including R34's.. haha

so yeah.. i guess in short, when considering engine conversions.. don't always pick what "goes hardest"... remember, your car is a CAR and has to work as a complete UNIT. not just wheels and a motor.

Considering the RB25DE was an option in the cefiros (as it was in the R32) I don't think a small increase in weight by going RB25DET is going to be noticed. Plus these things can be compensated for by adjusting spring and dampener rates and using adjustable swaybar.

One of my mates has an SR20 in his laurel and he swears by it, there was enough room to fit the intercooler and radiator in the engine bay and still retain the factory engine fan and shroud. I definitely considered this route but gave it to more displacement.

[Lum]

the structure of the car and the weight balance is not meant to have that much power fed solely thru the rear wheels

I'm planning this kind of conversion for the future. Would you still have this opinion for my car which is one of the 4WD Ceffys, or would a RB26 be ok in this application?

30 isn't really an option for me since I'm in the UK and we don't get many Commodores around here to nick the RB30 out of, lots of people crash their GTRs though

[Mr Eps]

sure do whatever you want i don't care im gonna go for a swim

[Ceffy_SA]

I think the RB25DET route is a good one, i should have gone down that path when my RB20 gave way, instead i re built my RB20 as a project, was easier to keep the RB20 also as it has the correct engine number in case of defect.

[daisu]

My train of thought was,

1) rebuild and modify rb20, going to spend a few grand on decent turbo/computer/injectors, and a few other things

2) convert to sr20, cost a couple grand upfront, good for weight distribution but still similar power output to RB20

3) RB25, again going to cost a couple grand upfront, especially if you get an RB25 gearbox, but with simple mods like exhaust and remap you can get large power gains over the previous 2 options.

4) then there was the thought of replacing the bottom end with an RB30, I stopped there because otherwise I'd get carried away.

But as I say before it all depends what you want to get out of the car, and your budget. For me, I tended towards the big power and low down torque, and figure I can compensate for any extra weight by adjusting the suspension. I'd love to try an SR20 though, especially with all the extra engine bay room.

Here's some photos of SR20 in my mates Laurel, as you can see he fit the intercooler in the engine bay with enough room to retain factory engine fan/shroud.

Edited December 3, 2008 by daisu