Jump to content
SAU Community

Recommended Posts

Instead of starting a new topic i thought ill post the question in here.... how is everyones fuel economy with the rb26/30 and 25/30 setups? mine is using alot of fuel and cruise ratios are spot on 14.7 and even when babying it around im lucky to get 300km to a tank which is shocking. Im yet to get the cam timing spot on until it goes on the dyno but hoping this is the issue and it will get alot better. I am running 4.3 diff ratio which means its on 2700rpm on the freeway at 100kmh and with the 3076r on it, its just a touch of throttle from being on boost, im thinking maybe the turbo is abit small as well which doesnt help?

So how many km's are you guys getting from a tank and what turbo are you running?

it could be done with internal gates, but an engine thats going to support 2x GT30's reliably isnt going to be cheap to begin with. why skimp on the turbo setup?

only reason is the stealth factor and engine bay room. however am worried bout boost issues...

you wont be able to hide twin GT30's. it just takes up too much space.

stealth comment was refering to the noise when the externals open up...

and gt30's taking up too much room....well no shit, so my original question still stands...can i fit in externals lol ?

  • 4 weeks later...

soooo my motor sounds like a bearing has gone for a little vacation...

was going to throw a wrecker motor in there, but i figure that for around the same price i could do a 3.0 with new cast pistons.

planning to use the 25 oil pump and throwing in some restrictors and a baffled sump.

with a 25/30 you tend to lose vct yes?

car was making 285rwkw on pulp with 20 psi by 3400 with an HKS 2835 pro s

would i be right in assuming that i would acheive full boost by 3000 or even a little less with the 3.0?

also would i be able to get close to the same power on less boost? say 1 bar?

xxx

soooo my motor sounds like a bearing has gone for a little vacation...

was going to throw a wrecker motor in there, but i figure that for around the same price i could do a 3.0 with new cast pistons.

planning to use the 25 oil pump and throwing in some restrictors and a baffled sump.

with a 25/30 you tend to lose vct yes?

car was making 285rwkw on pulp with 20 psi by 3400 with an HKS 2835 pro s

would i be right in assuming that i would acheive full boost by 3000 or even a little less with the 3.0?

also would i be able to get close to the same power on less boost? say 1 bar?

xxx

lose VCT? no you do not have to, you can run an external oil feed or do the internal mod (there is a thread in this section dedicated to it)

GT3076 turbos come on hard around 2500-3000rpm expect similar though you may find its slightly on the small side for a 30

less boost and same power? possibly hard to say how different it will be untill its been done. i haven't seen a 2835 powered 30 before but take a look at AL's setup taking the advantage he has with manifolds/head work the response should be similar.

vct is easy, no way you should lose it.

http://www.skylinesaustralia.com/forums/topic/251669-rb2530-rb30det-vvt-internal-oil-control/

with this setup and 25 pump i used 2x1.6mm feeds, worked out to ~20-30% (cant remember exactly) less flow then the standard 25 setup with the vct feed.

standard 25/30 comes out at around 8.3:1, compared to 9:1 for rb25, so you'll lose a little compression but this is obviously outweighed by the extra cubes. 3000rpm sounds about right tho

should be able to make the same power with less boost, but how much less is anyones guess. probs still need more than 1 bar tho

just thinking that with the more cubes that the turbo might be a little prone to creep... spose i'll have to wait till it's built and see ;)

i need to do this on the cheap side unfortunately otherwise i'd just go fully forged.....

at the moment my only option is rebuild my current 25 as stock, drop in a kinder surprise or go a cast build...

i figure that a cast built bottom end will be the strongest of the options ad while doing that it might as well be a 30

are you getting trent to do it? he should be familiar with what needs to be done. dont forget about costs to modify exhaust + intercooler piping etc. there are hidden costs to the 30 that you just dont think of until you run into them

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Here is the mess that I made. That filler there was successful in filling dents in that area. But in the middle area. I can feel dents. And I've gone ocer it multiple times with filler. And the filler is no longer there because i accidently sanded it away. I've chased my tail on this job but this is something else lol. So I'm gonna attempt filler one more time and if it doesn't work I'll just high fill primer the door and see where the issues are because guidecoat is of no use atm.
    • Ok, so I think I sort of figured out where I went wrong. So I definitely overthinked it, and I over sanded, which is probably a large part of the problem. to fix it, I ended up tapping some spots that were likely to be high, made them low, filled them in, and I tackled small sections at a time, and it feels a lot better.    I think what confused me as well is you have the bare metal, and some spots darker and some are lighter, and when I run my finger across it, it' would feel like it's a low spot, but I think it's just a transition in different texture from metal to body filler.    When your finger's sliding on the body filler, and crosses over to the bare metal, going back and forth, it feels like it's a low spot. So I kept putting filler there and sanding, but I think it was just a transition in texture, nothing to do with the low or high spot. But the panel's feels a lot better, and I'm just going to end up priming it, and then I'll block it after with guide coat.   Ended up wasting just about all of my filler on this damn door lol  
    • -10 is plenty for running to an oil cooler. When you look at oil feeds, like power steering feeds, they're much smaller, and then just a larger hose size to move volume in less pressure. No need for -12. Even on the race cars, like Duncans, and endurance cars, most of them are all running -10 and everything works perfectly fine, temps are under control, and there's no restrictions.
    • Update: O2 sensor in my downpipe turned out to be faulty when I plugged in to the Haltech software. Was getting a "open circuit" warning. Tons of carbon buildup on it, probably from when I was running rich for a while before getting it corrected. Replaced with new unit and test drove again. The shuffle still happens, albeit far less now. I am not able to replicate it as reliably and it no longer happens at the same RPM levels as before. The only time I was able to hear it was in 5th going uphill and another time in 5th where there was no noticeable incline but applying more throttle first sped it up and then cleared it. Then once in 4th when I slightly lifted the throttle going over a bump but cleared right after. My understanding is that with the O2 sensor out, the ECU relies entirely on the MAP tune and isn't able to make its small adjustments based on the sensors reading. All in all, a big improvement, though not the silver bullet. Will try validating the actuators are set up correctly, and potentially setting up shop time to tune the boost controller on closed loop rather than the open loop it is set to now. Think if it's set up on closed loop to take the O2 reading, that should deal with these last bits. Will try to update again as I go. 
    • More so GReddy oil relocation kits, sandwich plates, etc. all use 10AN fittings. And same, I've only used 10AN and my car sees track work (circuit, doing laps, not 10 sec squirt business).
×
×
  • Create New...