Urgent Info Needed On Plenums!

[25GTT]

OK have decided to get a plenum over the new turbo as budget is strapped.I am limited to 2G and that includes labour. I urgently need your help.

I will be ordering a Greddy plenum from nengun for $1100 prob on MOnday so I am URGENTLY chasing after as much info as possible before i order to make sure thisplenum is good for an r33 gtst!

What i need to know is EXACTLY what do i need to do if i get the greddy plenum? Do i need a new fuel rail? on 280 rwhp so might need anew fuel pump yeah but will the injectors be ok hitting close to 300rwhp? i hope so.

So besides changing the intercooler pipes around a bit what else do i have to do? is the XF throttle body ok to get done aswell at the same time? is the greddy plenum a nice HP increase? I REALLY Have to keep this below the $2000 mark!

Your opinions on this??

Thanks Guys!

Daniel

[Lenno]

hey, i could be wrong but don't the subzero plentums come for about $1000 with fuel rail and throttle body ? and look how quick there cars run !...at least worth a look.

lenno

[paydro]

yes im in the same boat as you daniel. im also after a aftermarket plenum but i have no idea on what to look for and what is the best option if anyone has some info on plenums it would be very helpful

[rev210]

daniel,

Ask Paul (gtst-vspec) about his. One word of advise from me is don't go any bigger in throttle body diameter than your stock one unless you plan on a 600+HP turbo.

Very good plenum the trust unit. As far as I'm aware the factory rail and injectors fit in.

[T0nyGTSt]

The Greddy plenum is the only Jap unit around.

It is recommended for easy fit but it is expensive and looks trick but it's less impressive power wise than you'd expect.

T.

[rev210]

T0nyGTSt,

peak power improvement isn't going to be awe inspiring on the factory turbo (maybe 5-10hp?). I mean that turbo isn't going to make 300hp at the motor with your car daniel given the kms the motor and turbo have already covered.

Engine response is improved for those with 'front mounts' and as such so is accelleration. Thats all I'd care about. then again are you trying to win a Dyno queen award with this car daniel?

[R33NT]

Hills Motorsports down in NSW have a very nice custom plenum with properly tuned individual runners. They go for around $800. They rework the bottom half of the standard GTSt (R33) plenum and build a new top half. I am told that it performs brilliantly.

I had a friend who went from stock plenum to Greddy plenum and i remember he was disappointed because there was no major gain. I think he was running 20psi boost.

[adam 32]

personally forget about the greddy plenum, the std plenum's design is very good and can support a decent amount of power.

i would save and do the turbo next - but it all depends on what your plans are for the car

in my opinion unless you are gunah run a rebuilt and strengthened motor at 4-500hp its not worth changing the plenum.

[Needajapcar]

has anyone ever looked into placing on a gtr manifold onto the rb25??? we all know they can flow well and with multiple throttles would seem better for responsiveness...... i mean the only major drama would be to get someplace to make up an adapter plate for it to fit onto the head and once one has been made up it would seem quiet easy to make more up possibly even cheaper......i myself along with a more mechanically gifted friend are looking into doing this once after my rb30det goes in..........

[rev210]

Although there is a minor gain in throttle response with multiple throttle bodies, as they wear (the shaft bushing) or when they get out of alignment, they totally suck to re-align and I'd rather chew my own leg off than piss fart around with that.

[Gradenko]

25GTT, something to keep in mind about the Greddy and Sub-zero plenums - no provision for factory idle control. Only a problem if you want to keep the factory ecu or powerfc and want good cold start, normal idle and air conditioning compensation. Its pretty high up on my plenum check list. I think the Hills Motorsport plenum keeps factory idle control and its not a bad price, so its worth a check out.

I've found two types of XF throttle body's, the 65mm and 85mm (could be 90mm). Sydneykid has mentioned the standard RB25DET throttle body (at 65mm) is good for at least 400bhp, so I'd keep it on for good driveability with the standard turbo. Even if you're planning on big power, change the throttle body later rather than sooner.

[Guest KILLER-T]

Hi 25gtt if you can get the Greddy one for 1100 bux then i would go for it that is a good price.Just keep in mind you will need a new throttle body or maybe you could use the factory one but i dont know if it will fit.As for the sub zero plenum they work well they come with a new xf throttle body and top feed injector rail.When i fitted mine i decided to take off the factory idle controll and cold start valve because i had a real rough idle and noone could fix the problem now without all the factory gear on the new plenum the car idles 100% better it starts fine when its cold so im happy

:uh-huh:

[Gradenko]

KILLER-T, I'm guessing cold idle and warm idle are all at the same rpm. How high?

[Guest KILLER-T]

It idels at 680rpm when its cold and 750rpm once its warmed up and with the power fc like most after market ecus you can adjust the amount of fuel your engine is getting at different operating temps.

[Gradenko]

Hmm, thats a fairly low cold idle speed. Suprised it doesn't stall in really cold weather, like engines of old (manual choke era). Glad it works for you though.

[Guest KILLER-T]

I adjusted the idle with the air bleed screw on the xf throttle body when the car was cold.It will stall if you let the bov vent but i dont let it boost untill its warm so its not a problem

[sidewaymambo]

you could buy the adapter plate for the stock throttle body for the greddy plenum..

Originally posted by KILLER-T

Hi 25gtt if you can get the Greddy one for 1100 bux then i would go for it that is a good price.Just keep in mind you will need a new throttle body or maybe you could use the factory one but i dont know if it will fit.As for the sub zero plenum they work well they come with a new xf throttle body and top feed injector rail.When i fitted mine i decided to take off the factory idle controll and cold start valve because i had a real rough idle and noone could fix the problem now without all the factory gear on the new plenum the car idles 100% better it starts fine when its cold so im happy  

:uh-huh:

[JimX]

I would get the Hills plenum if I didn't already have another (home-made) one. As already said, it has the ability to use the factory idle control. The biggest advantage to the front-facing plenums is better throttle response.

I wouldn't do it for outright power gains but if you can keep the total cost under a grand or so it would be worthwhile, because it makes the car feel better to drive as well as looking pretty neat in the engine bay.

Another (small) bonus is it makes your plugs and coilpacks much easier to get at.

[sidewaymambo]

OK, so what effect by using bigger throttle body?

[warrick]

does anyone have a pic of the hills plenum?or do they have a site with a pic?thanks for any help.

cheers

warrick