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RB20dET - R31 Coupe - Help

Angry

By Angry,
in Engines & Forced Induction

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Angry Proficient

Angry

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Posted

Hi,

Firstly i really appologise if this topic has been covered OVER and OVER and over again like a parrot. But i figure i'll get better answers if i do it this way as searching for it just makes me more confused.

In terms of boost and turbo's my knowledge is brief. And im getting confused pretty easily reading the misc. forum topics on a few topics. Originally i intend in going for something like a GT25R or GT28R. So i need a little help from the masses here.

I currently own a '88 Rb20 redtop ECCS R31 GTSX Coupe. And i'm lookin to improve on what i have - torque and power wise.

But in the way of dollars i'm thinking that a Rb25 turbo with a t04 Vtrim wheel , machined and balanced could be possibly more cheaper and just as effective as my other choice of a GT series turbo. Goal is to make roughly 200rwkw's on about 16 - 18psi at the most. Mostly coz my cars a daily i dont wanna get too crazy in that department as its still an Auto and it is 16years old with 160,000kms.

Anyways. Sorry for the lengthy post. I'll get to the point.

Could someone possibly help me out in making any reccommendations on this coz i really need some straight facts rather than changing my mind every 5mins on what i'm "gonna" do. :)

In terms of bang for your buck and ease (fitting wise) would i be better off with a RB25 turbo or would i be better off spending 1700 bucks on a aftermarket turbo?

I currently have 3inch hi flow exhaust and pod filter (and making 116rwkw on standard boost) - i will have shortly a FMIC and temporarily a bleed valve set to 10psi (on the stock turbo).

i also have GTR Injectors, Camshafts and Valve Springs on standby when i can afford to purchase an aftermarket ECU , adjustable cam gears and a EBC. I intend in replacing the turbo dump pipe when i settle on a definate turbo replacement , whatever that will eventually be. :wassup: - i dont intend in doing any bottom end mods at this stage. But i do want to have the head and exhaust manifold port matched and polished.

Also What exactly is standard boost on Rb20 .. i see ppl saying 7 or 6 ..and then 10psi .... confused :headspin:

Thanks for your time. Again sorry for the long post.

Matt

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Mr GTS4 Mentor

Mr GTS4

Posted
Posted

stock boost on my silver top rb20 is 10psi. the R33 runs about 7-8 stock.

with the turbo, its really upto you how you go but i think that the GT series turbo would be better cause its ball bearing and it will spool better on the Rb20 giving better response down low.

how you thought of getting a silver top head and putting it on your block? i have one and sold it to a guy in the same situation you are in now. they flow better too.

GTR cams, gears, and injectors are another good idea as well, the valve springs you don't really need for 200rwkw.

anyway yeah, whichever way you go its sounds like a good project :)

Angry Proficient

Angry

Posted
  • Author
Posted

i didnt think about a silvertop head .. wasnt sure they actually fitted.

only thing that deters me so much from GT series is buying a suitable turbo ..dont wanna go too big and at the same time not too small. (trying to work out reading compressor maps as we speak.)

thanks for the input Mr GTS4

Matt

Angry Proficient

Angry

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Posted

what is it with you and gearboxes? if it goes bang it goes bang ..bets on that it wont and i'll get my target .... thanks for your input.. but i've talkd to plenty of ppl regarding the autos.

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted
what is it with you and gearboxes? if it goes bang it goes bang ..bets on that it wont and i'll get my target .... thanks for your input.. but i've talkd to plenty of ppl regarding the autos.  

Bump

well the people you talk to are mad or a bit "out" of the know

your going to blow it. I can promise you that. And its a min of 2k that you'll have to factor into your expenses at some stage.

Angry Proficient

Angry

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Posted

yea definately.. i'm not deniening the fact that it will blow at some stage .. when it does ..and if it does .. manual it shall be. i'm not particularly fuss. but i do rather the arm chair olympics style of driving.

i've installed a boost guage and its getting around the 10psi mark on a cool evening. some times it may just get over 10 by a fraction. .. i would of thought i would be making more power than that .. although it is running rich as bags at the top end and my curve really suffers from it.

I have seen standard autos go into rotarys from Rank and head down the 1/4 mile pretty rapidily. i'll have to do more investigation in regards to a tougher tranny. but i dont want break neck shifts.

Thanks for the input Ash.

Matt

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