Jump to content
SAU Community

Recommended Posts

so anyway my neo 25 is pretty well spot on in terms of power, response and torque. I did want to change the stock over the top of the motor style manifold for the sake of tidying up the engine bay and so forth. i DONT want to go with a cheap shit copy manifold. I would get a greddy manifold but at around 700 odd for a new one i was thinking why not go with GTR ITB's and plenumn. whats needed to make them fit and would it be a total waste of time and money?

looking at changing the diff back to a 4.1 so will need a tad more midrange torque and power to make up for the ratio change from 4.3. this might be one way of doing it?

fwiw a plazmaman manifold is out the question.. they are HUGE and IMO overpriced.

Link to comment
https://www.sau.com.au/forums/topic/360698-to-go-itbs-or-not-worth-it-read-on/
Share on other sites

You need an adaptor plate made up to have the ITB/plenum go on i believe.

Not the simplest job, but certainly possible.

Blitz used to make an adaptor... I believe they stopped doing it :(

The adaptor was overpriced too lol, but then it was a one-of-a-kind make

Am looking at going this setup myself, although on R33 RB25, not Neo.

Rather than a Blitz style adaptor I am leaning more toward welding a plate to the standard RB25 runners which the GTR throttle-bodies can then be bolted to. This way original injectors, idle control, etc can all be kept.

Also the injectors are kept exactly where they were designed to be, etc.

RIPS NZ can do the whole job for somewhere around $600 or look at designing/doing it yourself (I am)

so anyway my neo 25 is pretty well spot on in terms of power, response and torque. I did want to change the stock over the top of the motor style manifold for the sake of tidying up the engine bay and so forth. i DONT want to go with a cheap shit copy manifold. I would get a greddy manifold but at around 700 odd for a new one i was thinking why not go with GTR ITB's and plenumn. whats needed to make them fit and would it be a total waste of time and money?

looking at changing the diff back to a 4.1 so will need a tad more midrange torque and power to make up for the ratio change from 4.3. this might be one way of doing it?

fwiw a plazmaman manifold is out the question.. they are HUGE and IMO overpriced.

Ran Rb26 plenum with blitz adaptor kit on my rb25 (non-neo) and recommend it. Its not a easy job and my advice would be to take the engine out as it makes the job 100x easier.

What needs to be done to make it fit:

1: Adaptor Plates

2: Remove Radiator water outlet on Rb26 Plenum and weld on the rb25 plenum radiator water outlet

3: R33 S1 throttle positioning sensors will bolt onto the rb26 plenum

4: GTR throttle cable (gts-t throttle cable is too long, i just loop mine inside the cabin but its easier to just get a gtr cable)

5: Make a bracket to hold the throttle cable

6: There is a big air box on the underside of the gtr plenum

gallery_15274_3064_206110.jpg

What we did was remove the box and made up a pipe section which allow all the vacuum lines to be connected.

This is needed as the std rb25 filter will hit the gtr plenum

7: You will need to use the gtr fuel rail, which means you need to wire in the plugs for the GTR injectors and also wire in the gtr resistor pack for the injectors

I think that is about it, if i remember anything else i post up and if you have any question just ask

Edit: Also the gains, i pick up around 200-300rpm, before the swap i had full boost around 3300rpm after plenum install was getting full boost around 3000-3100rpm.

Will try and find some photos of the conversation

Edited by Kaido_RR

I've been looking at this for a while and all the people I've talked to everyones been happy with the results, no one has gone back or changed to a greddy/style.

At the end of the day it's not a huge gain for the work involved- but it is a gain.

Some guys have used 10mm alloy plate to make up the adapter- I was going to use something alot thicker to create a longer distance between the tb and ports for slightly better low end torque.. it all depends on the clearance to the strut tower too.

I say go for it and post up the results as a pure, before-after.

Cheers

Justin

If your hoping to gain actual transient response within the usable rpm range of that turbo(4000-7000rpm) then it will help. However I wouldn't jeopardize runner length unless you dont mind loosing mid range power (1000-55000rpm) and mid rpm spool rate.

If your hoping to gain actual transient response within the usable rpm range of that turbo(4000-7000rpm) then it will help. However I wouldn't jeopardize runner length unless you dont mind loosing mid range power (1000-55000rpm) and mid rpm spool rate.

i didn't lose anything from doing the swap.

As XRATED mention it is not the easies swap and does cost abit, however i found no negatives to the swap other than the cost/time it takes to do the swap.

Plus it makes the engine bay look so much neater

img4586.jpg

Edited by Kaido_RR

If its only 600NZD currently, you'd be hard pressed to beat locally with time/effort it given how poor their dollar is at the moment :thumbsup:

can do a CAD drawing of the adaptor easy enough.. once this is done i have a machinist who can work off the file. shouldnt cost any where near as much as buying a made kit.. there is however trial and error. I would like to see some pics of plates used to get a rough idea what to expect atm.

thanks for the pics posted so far guys... loads of info here already

i didn't lose anything from doing the swap.

As XRATED mention it is not the easies swap and does cost abit, however i found no negatives to the swap other than the cost/time it takes to do the swap.

Plus it makes the engine bay look so much neater

img4586.jpg

Have you got dyno graphs to prove back to back runs with nothing but the intake manifold change. Talk to some of the RB25 guys that go to the plazman manifold - they all experience some bottom end loss due the runner length halving.

well i did some searching and it seems a member did it all on a neo motor with no adaptor plate... sweet as! looks like its pretty straight forward then.

as per here http://www.skylinesaustralia.com/forums/topic/247435-mating-rb26dett-throttle-plenum-on-rb25det-neo-head/page__view__findpost__p__4606691

Have you got dyno graphs to prove back to back runs with nothing but the intake manifold change. Talk to some of the RB25 guys that go to the plazman manifold - they all experience some bottom end loss due the runner length halving.

Roy saw this issue when he changed to Plazman/6boost manifold combo. (check his RB02 build thread for more detailed info)

Which part was to blame - hard to say of course - either way upgrading was a costly exercise for less... :(

plazman maniflolds are HUUUGE thats for sure... they really only suit VL's and their large engine bays. i had the misfortune of working on a 34 with one fitted and you couldnt change the oil filter from the top thats for sure. or the sides for that matter.

Have you got dyno graphs to prove back to back runs with nothing but the intake manifold change. Talk to some of the RB25 guys that go to the plazman manifold - they all experience some bottom end loss due the runner length halving.

Ummm do you mean a Greddy manifold? Plazmaman doesn't touch the runners.

While getting to the oil filter is harder, it aint that big of a deal. The only thing that made mine harder is the extra braided lines teeing into the fuel lines for the nitrous being in the way.

Personally I wouldn't be welding onto the head... Tig is a 'hot' process. There are just so many finely machined clearances to be buggered around with by adding that much heat.

An adapter plate can be made as easily as a slice of alloy plate, the two types of head gaskets and some basic hand tools.

And if it all goes tits up you can put it back to stock.

Cheers

Justin

Have you got dyno graphs to prove back to back runs with nothing but the intake manifold change. Talk to some of the RB25 guys that go to the plazman manifold - they all experience some bottom end loss due the runner length halving.

i will have to check to see if i still have my dyno print outs.

Nothing else was change when i did the plenum swap if i remember right, i think i even ran the same boost on the retune. Interesting that when the retune was done, the whole tune had to be wipe and start again as everything was out with the gtr plenum on.

For me no bottom end loss, the car was more responsive everywhere.

The blitz plate are only 100mm thick maybe less. i had the plate which connects to the head slightly ported to suit the head ports.

The kit is now on a friends car, however it is having turbo issue so has not had a proper retune. Will be interesting to see the result he get as it is running an identical setup to what i had (even has my old hks pro s turbo)

Edit: just for info the photo i posted was with my newer setup which was running a 3037S however the result were not as good as my engine was dieing, very low compression and eating oil

Edited by Kaido_RR

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

    • I know why it happened and I’m embarrassed to say but I was testing the polarity of one of the led bulb to see which side was positive with a 12v battery and that’s when it decided to fry hoping I didn’t damage anything else
    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
×
×
  • Create New...