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To Go Itb's Or Not Worth It? Read On

Simon-S14

By Simon-S14,
in Engines & Forced Induction

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rob82 Mentor

rob82

Posted
Posted

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.

You remove the top half of the std manifold to fit the plazmaman plenum - hence you halve the manifold length or close enough to it anyway.

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

Its funny that you say it was more respsonsive everywhere. Are you sure it wasnt that you have twice the available air at any throttle position.

Its like tuning electronic throttles - all you have to do is give them more actual throttle at the same APP and they think the car is so much faster - when in reality at full throttle it still makes the exact same power!

PM-R33 Grand Master

PM-R33

Posted
Posted

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.

You remove the top half of the std manifold to fit the plazmaman plenum - hence you halve the manifold length or close enough to it anyway.

Still not following you dude. What are you exactly halving the length of? Runners stay the same and you are swapping one plenum for another plenum which is larger.

I don't see what is getting halved (or smaller for that fact).

FineLine Grand Master

FineLine

Posted
Posted

Pretty hard to prove or disprove what plenum is or isnt better. Very few if any have ever did a plenum only change and dynoed the car before and after.

I've been using a greddy with a phonelic spacer to increase runner length and I have no complaints. I looked at the plazmaman product and others but to me it was like trying to cram a 200 litre fuel drum under the bonnet.

Skyline engine bays are cramped enough and hard enough to work on under the plenums and in that general area without adding to it.

rob82 Mentor

rob82

Posted
Posted

Still not following you dude. What are you exactly halving the length of? Runners stay the same and you are swapping one plenum for another plenum which is larger.

I don't see what is getting halved (or smaller for that fact).

The std top half of the manifold is not just an open plenum it has about 5inches of runner in it before it opens up into a small plenum just before the throttle body.

Nee-san Grand Master

Nee-san

Posted
Posted

Theoretically it should be better.

do the maths to see whether your six ITB have a greater area then the usual 100mm job everyone seems to put on the car.

there is also the benefit of minimizing un-throttled air volume in the plenum itself.

whether it would make a difference on such a compromised application as a pretty normal skyline engine is something you will have to find empirically :/

XRATED Veteran

XRATED

Posted
Posted

Pretty hard to prove or disprove what plenum is or isnt better. Very few if any have ever did a plenum only change and dynoed the car before and after.

I've been using a greddy with a phonelic spacer to increase runner length and I have no complaints. I looked at the plazmaman product and others but to me it was like trying to cram a 200 litre fuel drum under the bonnet.

Skyline engine bays are cramped enough and hard enough to work on under the plenums and in that general area without adding to it.

How thick is your phenolic 'spacer' gasket, isolator- etc? Was it bought or was it fabbed up for you? If so where and who did it for you?

Cheers

Justin

GravyGarage Community Regular

GravyGarage

Posted
Posted

Woah good thread. Thanks Kaido_RR for that little guide should help heaps when I put mine together. I managed to pick up inlet and adapter plate, only one I have ever seen for sale. Can get some pics of my adapter plates if you want guys?

Simon-S14 Grand Master

Simon-S14

Posted
  • Author
Posted

would be fantastic!

im still a bit baffled by the link i put up earlier of the guy who did ITB's on his neo with NO adaptor plate... how is this done does anyone know?

i'd pm the guy but he doesnt look like an active member of SAU anymore

wlspn Proficient

wlspn

Posted
Posted

X-Rated, I know a place called Mace Engineering make the phenolic isolators/spacers.

They advertise them on their website as 10mm or something for around $100 but apparently they can supply whatever thickness you request. Unsure of extra costs though...

If you get some prices let us know.

& Simon-S14, did you read his whole thread?

He welded on to the head, then machined his welding flat, tapped threads, etc to re-create the RB26 stud pattern on his NEO head...

Quite a lot of work!

FineLine Grand Master

FineLine

Posted
Posted

How thick is your phenolic 'spacer' gasket, isolator- etc? Was it bought or was it fabbed up for you? If so where and who did it for you?

Cheers

Justin

It added 30 mil to the runner length and was made by Mace engineering in Melbourne. It is an amazing insulator s well. Even after prolonged high revs I can put my hand on the plenum.

badhairdave Proficient

badhairdave

Posted
Posted

Can't find the thread now but str8e180 has posted photos in the past of a modified set of rb25 runners with flanges to suit the 26 itb's. So i'd guess powertune could do something for you too.

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