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Cubes

By Cubes,
in South Australia

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Ryanrb25
Ryanrb25

i went for a hills run last night in the 31 with the roads very slippery.....was much fun. Had to bed in the bottom end bearings so yea..took it for a strap.

DSTROY
DSTROY

Hey Ryan, do you know how to fit a set of drop spindles to the front of a hilux???

Madaz
Madaz

Dam straight Damo would rather do SAU them heroin gts4 are 4.1 because they share the same parts from the gtr i think r32 gtst is 4.3 because of the lack of torque from the rb20

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Ryanrb25 Grand Master

Ryanrb25

Posted
Posted
also note i couldnt find it before

but i didn't go against what you said just to be an asshat it is documented a RB25 turbo on a RB20 engine is quiet capable of 14-15psi this is why i believe on a RB25 engine it isnt running out of efficiency @ 13-14

source

Have a look at some efficiency tables. People dont realise that it's not all about boost in alot of cases. A stock turbo works sooo much harder to produce 13-14psi than a much larger turbo. A smaller turbo working harder than a larger one has 10 times more heat than a slightly larger turbo on the same psi. Heat is the main cause for it's loss in efficiency. Heat is the main contributor for power loss. Heat is another contributor for detonation. Heat Heat Heat. 10-12 PSI is the effiency range for that sized turbo combination. It's been proven over and over and over again. It pays to spend time on all sorts of cars using different sized turbo's and watching power DIVE when you add any more HEAT and BOOST into a turbo that isn't efficient for those settings.
Also, you can't compare an rb25 turbo's efficiency on an RB20 because an RB20 if your unaware is a 2L. Being a 2L it has less stroke, less flow, less heat so therefore the effiencienfy range for that specific turbo goes up a tad. Efficiency can also be determined with front and rear housing not matching at a certain flow level. At 10-12psi the rear housing of the rb25 turbo is just large enough to not create surges caused by lack of flow in relation to how much the front housing is squeezing into the motor. Where as at 12psi and above, the front housing is flowing a tad too much volume for that tiny little rear housing to handle....sure it will cope, but it gets f**kn hot. Hense where the heat comes into play, in turn heatsoaking the front housing a whole lot more..taking efficiency away from the turbo. Another reason efficiency can be effected is because the front wheel of the compressor is designed to flow a certain amount of air at a certain speed. Just like a water pump, Behaving fairly simular, if you speed the front wheel up and the pitch of the front wheel is incorrect for speed it is turning, Just like a water pump it can cavitate the air and be useless. Hence why if you use the wrong pitch of the prop on a plane at the wrong speed then the plane will loose momentum. Once again the same with a water pump, if the impellor's pitch doesn't suit the speed it is turning at it will can cavitate and there for loose efficiency.

understand madaz?

DSTROY Grand Master

DSTROY

Posted
Posted
Chad, are you running standard internals? Or are you running some form of 26/30 or stroked 2.8 kit lol :P

Weren't you pumping out 230kw with the standard turbo's? That's nearly a 100kw power gain! Lol that's crazy dude.

Yeah it was 230kw before and as Luke said im just running GT2860-5's on a standard internal R33 GTR motor.

DSTROY Grand Master

DSTROY

Posted
Posted
awesome effort chad!

Thanks mate, i also did a few mods to the manifolds and dump pipes to improve air flow, and also hollowed out the AFM's as they aren't used, which would of helped a little.

ovrtym33 Proficient

ovrtym33

Posted
Posted
So the Skyline is now done. Thanks to Andew (blue32) for fitting the turbos for me. It made 316rwkw on the Willall dyno. Im very happy with the end result :P

thats a great result Chad

WELOCOME TO THE 300+RWKW CLUB.........

Madaz Grand Master

Madaz

Posted
Posted
understand madaz?

yeah mate but i still cant help thinking that a RB20 pushing 15psi is going to put out similar heat to a RB25 pushing out 13-14psi

i only had on a few occasions heat soaking on my car so i know it does happen when you push the standard turbo too much

looks like a nice figure there Mitch but i believe there running less brake on the rollers to inflate your figure there Mitch

(OO)Firty Free(OO) Rising Star

(OO)Firty Free(OO)

Posted
Posted
looks like a nice figure there Mitch but i believe there running less brake on the rollers to inflate your figure there Mitch

I agree steve my mates GT went from 224 at Aussies to 257 at KPM with the addition of underdrive pulleys only :P (which in reality would be 5-10rwkw at the most). Hows your car doing mate got it sorted?

Madaz Grand Master

Madaz

Posted
Posted

Hi Lee na i minor issue of not being able to boost part 5k rpm has arisen will be at adrians friday to drop my front shaft and to smooth out the lower rpm and double check afr's as well

my future plans for big injectors may have changed also due to a slight drop in compression nothing to worry about but enough to know its tired and wont support 300 unless E85 is a lot more forgiving which i think it is more research needed and a chat to adrian

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