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Gts4 Rb20 Upgrades

MJTru

By MJTru,
in Engines & Forced Induction

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MJTru Mentor

MJTru

Posted
Posted

Hi mate.

I have build rb25 in the past and found that the motors have a few flaws. stock piston ring landings are weak. oil pump and crank needs a collar, head needs resistors and extra oil drain to return oil back to the pan faster. Hydraulic lifters.

well what i would like to know is from a stock stand point I've been beating my RB20 and it taking it totally stock, my stock rb25 would have died already. now are these motor stronger, I want to know if the head and oil pump has all the same flaws as the rb25.

I'm planning on rebuilding it soon. does the rb20 have hydraulic lifters and oil pump flaws like the rb25.

Dam its a fast little car. lol

My currant mods are Holset hx35 turbo, FMIC, stock BOV, gtr fuel pump, exhaust, 550cc injectors, z32 AFM.

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GTScotT Grand Master

GTScotT

Posted
Posted

The motors are essentially the same but a 2WD RB20 is known to be more durable than an RB25 at reasonable power levels (<300kw). I believe that is just the difference in torque output that is pushing the RB25 closer to the limits of its make up, knowing they are produced very similarly.

As for an AWD variant I am confident the oil pump issues will be more prominent like in the GTR's. I am of the opinion the attessa engagement plays a factor in how long it takes a short nose crank to destroy a pump, FWIW this is not fact and is solely my own opinion on the matter. I will know more in time as a friend has recently ventured onto the 32GTS4 w/stag NEO path.

In terms of oil problems all the RB's share this.. I believe the RB26s suffer the most but am unsure exactly why, others will be able to give more detail here and if you should be concerned.

discopotato03 Grand Master

discopotato03

Posted
Posted

My guess is that RB26s have the breathing abilities inc those throttles to enable sustained high rev running . An RB20 is probably more dirable if thrashed everywhere because of its shorther stroke and smaller diameter lighter pistons . Having the same block deck height means longer rods and a better rod stroke ratio .

If you could do it legally a Neo 25 would be a good upgrade path IMO and has conventional shim on bucket (non hydraulic) valve train . Maybe even a 26 how far do you want to go ?

A .

discoPumpkin Community Regular

discoPumpkin

Posted
Posted

While there a good motor and fast, keep in mind they will not make 300rwkw like a an rb25/26/30 or even an sr20. The other downfall is there lag and low bottom end torque, due to there short stroke and low displacement. + ontop of that u have the extra weight of a GTS4 to contend with.

B4 rebuilding the motor, i'd 1st be considering any of the above motors, the rb26 will fit straight in

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