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why shouldn't I turbo a RB25DE?

CerealKiller
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4door_Sleeper Veteran

4door_Sleeper

Posted
Posted

If only it were that easy.

In the long run it is more expensive than just purchasing a turbod skyline.

The higher compression ratio is good when you are off of boost, but will cause your engine to detonate at a lower boost level, so in the end it will be a bit more responsive off boost but lack the power under boost.

Other factors to consider in the conversion are brake upgrades, engine management etc,

inissane Proficient

inissane

Posted
Posted

RB25DEs can go to hell :wassup:

you are kidding arent you, just put in an rb20det or rb25det, otherwise if u are an atmo nut (nothing wrong with that) sell it and get a car that is an atmo performer.

the problem with your reasoning is that on the one hand you are modifying an atmo engine for performance by adding a turbo, while on the other, the advantages of the forced induction are restricted by a want for off boost response/power

thats just my ideas, good luck

Cubes Grand Master

Cubes

Posted
Posted

It will be fine. IF its tuned well.

The only reliability issue could be the N/A has no oil squirters to help remove heat from the pistons. RB30ET's dont run piston oil squirters so in practice it probably isn't an issue for moderate power levels.

If compression was an issue throw in a thicker head gasket. Thats not difficult, especially if done before the motor is dropped in. :P

predator Grand Master

predator

Posted
Posted

there is a lot of "I've heard...", "don't bother", "it won't work", "waste of time".. etc - but not many facts or actual examples.. I am sure its good for 200rwkw without too much dramas and proper tuning. It's done in japan quite a bit.

If you are doing the n/a.. you could always go in with the "who cares if it blows".. and if that times comes just replace the bottom end with a built rb30 bottom.. as you'd already have the top and loom in place then.

In your case you already have all the decent turbo support systems (gearbox, clutch, diff, brakes, etc) so it might not be so stupid.

if you are swapping in an rb25 though, that does seem a little pointless just to swap in the n/a version, when for maybe $1000-2k more you can get the turbo version which will last no questions.

Roy Grand Master

Roy

Posted
Posted

My only concern would be that RB25DET pistons have questionable ring lands, supposedly, so have been known to fail in this are if the tune isnt spot on.

So the RB25DE pistons, are they similar, worse , better...especially with the extra point of compression? Who would you have tune it, what management??? What power are you after?

I dont think its too bad an idea provided you can answer the above...but you know what i ultimately think you can have for $4k all up if your not chasing big power...;)

Dyno_RacePace.jpeg

12.9s and a throw away engine should it every go bang, lol...stirrs the pot:)

GTRgeoff Grand Master

GTRgeoff

Posted
Posted

There is no reason not to do this, as long as your goals are set realistically and you plan for reaching them in a logical way.

So it won't handle high boost???? set it up for low boost to take advantage of the high CR. The yanks love to do this with hondas. Saab do it with a V6 (or used to) with one low presure turbo on one bank. What turbo to use? Maybe not a standard RB25 but something smaller. Maybe a hybrid with the 25 (modified steel) exhaust and 26 compressor. I'm no expert on turbos but it will involve some thought and suck it and see.

Anyway, good luck.

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