Jump to content
SAU Community

Recommended Posts

  • Replies 101
  • Created
  • Last Reply

Top Posters In This Topic

I still think the complete 26 top end is the go . If you look at RB20/25/26 heads on the inlet side you'll find numerous detail changes to suit their application . I believe the bolt patterns are different because of access to the fasteners to assemble it all .

As for inlet system development I'll bet any money that Nissan put more into developing the RB26 inlet (as a package) than GReady ever could .

Cheers A .

im sure alot of research did go into the gtr plenum, im going to stick with it for the moment and see how it goes, then i can tell u of the results that i have seen ok steve and others. I would like to get the greddy one but already have the gtr one so im going to see what i can make outta it.

Agree with discoepotato. Very good statement about Nissan. So true as well. A lot of people think that aftermarket stuff is the be-all and end-all of car developement. None of these guys would have any idea what its like behind the doors of an OEM facility.

Agree with discoepotato. Very good statement about Nissan. So true as well. A lot of people think that aftermarket stuff is the be-all and end-all of car developement. None of these guys would have any idea what its like behind the doors of an OEM facility.
Don't be dumb !!

When Nissan were developing the GTR plenum, they had the same restrictions as they have with everything else they look into when developing a car......Accountants not being the least of their problems, they have to optimise design parameters to suit broad conditions of use. An aftermarket developer, like GReddy, doesn't have to comply with emissions design criteria, and their targeted performance parameters are a heck of a lot narrower than Nissan's ever were.

It's common knowledge that the GTR plenum has a flow problems with Nº1 & 6 cylinders, but I'd love to see evidence of the flow test results you claim to have heard.

Don't be dumb !!

When Nissan were developing the GTR plenum, they had the same restrictions as they have with everything else they look into when developing a car......Accountants not being the least of their problems, they have to optimise design parameters to suit broad conditions of use. An aftermarket developer, like GReddy, doesn't have to comply with emissions design criteria, and their targeted performance parameters are a heck of a lot narrower than Nissan's ever were.

It's common knowledge that the GTR plenum has a flow problems with Nº1 & 6 cylinders, but I'd love to see evidence of the flow test results you claim to have heard.

I have done the flow tests, what would you like to know? Let me start the ball rolling, we saw none, zero, zilch, not one cracker, nothing, SFA improvement from testing the GReddy plenum on a GTR inlet and cylinder head at airflows equivalent to 750 bhp.

So if you spend your $1500 on a Greddy plenum and I spend my $1500 on something else, my car will be faster until we get to 750 bhp. And even over that the difference is nowhere near as significant as $1500 worth of other stuff.

Put it simply, personally I have demonstrably better ways to spend my money.

I have done the flow tests, what would you like to know?  Let me start the ball rolling, we saw none, zero, zilch, not one cracker, nothing, SFA improvement from testing the GReddy plenum on a GTR inlet and cylinder head at airflows equivalent to 750 bhp.

So if you spend your $1500 on a Greddy plenum and I spend my $1500 on something else, my car will be faster until we get to 750 bhp.  And even over that the difference is nowhere near as significant as $1500 worth of other stuff.

Put it simply, personally I have demonstrably better ways to spend my money.

Sk,

The original post was about putting a GTR Plenum on a RB25 ? Not a GTR? what are your thoughts on that ?

SK,

I don't doubt for a second that the GReddy Plenum, in either RB25 or RB26 applications, only comes into it's own after a certain level of airflow is required, nor do I doubt that the OEM designs are good ones, but I'd still love to see the figures so as to appreciate just how futile the whole argument really is.

Like BBQ though, I'd like to know your POV regards the RB26 plenum on an RB25.......

*mod hat on* Keep it clean guys... *mod hat off*

I did some research on the greddy plennums and found that stock RB25 unit was good up to 250rwkw.. I was going to buy a greddy unit but found my self wondering why none of the worked GTST and GTT's at tokyo autosalon had them.

The stock unit is under appreciated.

While I agree the stock unit is more than capable of supporting decent horsepower, I think the main difference is how it makes the horsepower. Ever since I've had my Greddy manifold on my midrange power has dramatically increased, and I'm yet to even see other cars match my dyno graph for average power.

Why not tell us who you are SK so we can see if you are what you claim to be as you have posted a few Facts that have been anything but so i feal its time you name your self.

Steve the people that I want to know, know. The problem is if I tell EVERYONE, I will get hundreds of retail calls. As you know, I am not in the retail business, I help some people out, particularly when they have an interesting problem, but that's it. I already get 30+ PM's per week and I reply to every single one. I don't make any money out of it, I don't charge anything, I don't have anything to sell.

I made the mistake about 3 years ago on another forum, one that I have lots of experience in, more than Skylines in fact. But I got pestered so much I had to change my phone number. I no longer contribute to that forum. I don't want the same to happen here.

I promise you this, next time I am in Perth with the race team, I will drop in and pay you a visit. I know where you are in Welshpool, just up from the Leach Highway. Will I need to bring a body guard? :uhh:

While I agree the stock unit is more than capable of supporting decent horsepower, I think the main difference is how it makes the horsepower. Ever since I've had my Greddy manifold on my midrange power has dramatically increased, and I'm yet to even see other cars match my dyno graph for average power.

Let me apologise for this post before I start, but regular readers will know why....

Paul where did you get the term "average power"? From ME, that's where you got it from, I introduced that terminology to this forum. Before I explained it, you didn't even know what it was. You didn't even know why it was important, much the less how to calculate it. Don't bother, I have the posts to prove it.

So don't try the

"I'm yet to even see other cars match my dyno graph for average power"
, without even trying I found 20 on here that shoot on it from a great height.

Let's get down to facts.....

Ever since I've had my Greddy manifold on my midrange power has dramatically increased,

I simply don't believe you, show me the before and after dyno graphs and prove that the ONLY change was that from the standard manifold to the Greddy. You and I both know you can't make that claim, you changed lots of things, not to mention tune at the same time. Maybe Steve's brilliant tuning gave the increase in midrange and it would have been even greater with the standard inlet manifold.

Time to apologise again for this post, but sometimes ya just gotta say it. :fart:

Sydneykid & Steve SST - how old are you both? Its clear you have differing opinions on various issues but your constant arguements and bickering is getting a little old now.

How about giving it a rest and concentrating on continuing to offer the fantastic tech info that both of you have been providing to SAU?

Sydneykid & Steve SST - how old are you both? Its clear you have differing opinions on various issues but your constant arguements and bickering is getting a little old now.

How about giving it a rest and concentrating on continuing to offer the fantastic tech info that both of you have been providing to SAU?

Hi Blitz, I am sorry if you are offended by reasoned discussion, well at least my half of it is. I know from experience that you can put two circuit race engineers in a room and they will both have differing opinions on many subjects. I had 2 of them in heated argument last weekend over whether Penske or Ohlins were better.

What am I supposed to do? If I stay silent, it is taken as agreement, if I put forward a rational argument , I am accused of bickering. :freak:

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

    • You're not wrong, but more than a few times I've heard of people running into issues where their injector characterization isn't quite right and that approach works for that specific configuration but once they switch over to a new set they discover a whole bunch of stuff wasn't set up correctly. It's slightly more annoying to reverse engineer the OEM MAF transfer function but you already have the sensor wired up to the factory harness so keeping it around for a few weeks more while you figure out the tune is easy enough. I've seen GM also use a combination of both MAF + MAP in their ECUs before, MAF is for steady state and a calculation of the cylinder VE to correct the base VE table, then in transients it uses that calculated VE + raw MAP to determine cylinder filling somehow.
    • I know this one’s the BB one. My tuner did make mention about the actuator. I am curious about the VCT as well
    • Might also needs a stronger actuator with the right preloading. With older 2019 built bush G3 units, BB upgrade or 21U housing down size makes a pretty decent gain in response as well. 
    • Hey lads  so im finally putting together my rb30 forged bottom end and ran into an issue. I measured my main bearing clearance with arp main studs torqued to 60 ft-lbs using ACL H series STD size bearings and standard, un-ground crank shaft journals and got an oil clearance reading of about 1.3 thou measuring straight up and down and about 2.8 thou measuring at a 45 degree angle (just above and below the parting line). My machine shop said they measured the main tunnel and it was all within spec (they didnt say the actual measurement) and to go with a standard size bearing, which i have done and the clearance is too tight, I'm guessing because of the extra clamping force from the arp studs distorting the main tunnel. I was wanting to run about 2.5 thou main bearing clearance.  My questions are: 1. could i just use the HX extra 1 thou clearance ACL bearings? that would fix my straight up and down clearance making it about 2.3 thou, but then would the side to side clearance be too big at around 3.8 thou? 2. what actually is the recommended main bearing clearance for measuring near the parting line / side to side. i know its supposed to be bigger as the bearing has some eccentricity built into it but how much more clearance should there be compared to the straight up and down measurement? at the moment there is about 1.5thou difference, is that acceptable or should it be less? 3. If i took the engine block + girdle back to the machine shop and got them to line bore the main tunnel (like i told them to do the first time, but they said it didnt need it) what bearing size would i buy? the STD size bearing shells already slide in fairly easily with no real resistance, some even falling out if i tip the girdle up-side-down. If im taking material out of the main tunnel would i need a bearing with extra material on the back side to make up for it? this is probably confusing af to read so if something doesn't make sense let me know and ill try explaining in a different way. My machine shop doesn't come back from christmas break until mid January, hence why i'm asking these questions here. TIA for any help or info 
    • I bought the model back in Japan in Feb. I realised I could never build it, looked around for people who could build it, turns out there's some very skilled people out there that will make copies of 1:1 cars or near enough. I'm not really a photo guy... but people were dragging me in a group chat for the choice of bumper as someone else saw the car before it was finished as they are also a customer of that shop. I took the photo in the above post because I was pretty confident that the lip would work wonders for it. Here's some more in-progress and almost-done pics. It gives a good enough idea as to what the rear looks like!   I have also booked in a track day at the end of January. Lets all hope that is nothing but pure fun and games. If it's not pure fun and games, well, I've already got half an engine spare in the cupboard 
×
×
  • Create New...