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Modified Rb26dett Intake Manifold

noone

By noone,
in Engines & Forced Induction

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noone Experienced

noone

Posted
Posted

Brought this a looooong while back an finally am getting my "built" Motor in an wondering now if I wanna risk using it or not

Looking to get opinions

According to the guy I brought it off it had been flow tested an addressed nicely the flow problems inherent with the stock manifold

was claimed to be off a big big horsepower rb26

Has been ceramic coated and has had a 1/8th bsp hole added ,I assume for a maf sensor or something

Will just block that off with a plug as am planning on using AFM's assuming a standard brass plug orta hold okay

connection to cooler has been opened up to 4 inch so will need a 3.5 to 4 inch silicon reducer there

Am thinking I will try it out an see but wondering if anyone has any opinions or even better recognizes it??

Sadly I didnt get results of flow testing when purchased an as far as I know no one in Darwin has a flowbench capable of testing it

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post-33041-1257250908_thumb.jpg

post-33041-1257250988_thumb.jpg

post-33041-1257251025_thumb.jpg

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https://www.sau.com.au/forums/topic/294743-modified-rb26dett-intake-manifold/
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Super_Dude Enthusiast

Super_Dude

Posted
Posted

Looks good to me. Flow test it to find out. Ideally you should run an Intercooler with a 4" exit and run 4" all the way.

Also the mine's car doesn't run a stocker, it runs a nismo. You can even see where the nismo badge should be in the engine bay shots and they just put a Mine's badge in it's place (just like the "Mine's" Mafs)

jonn Proficient

jonn

Posted
Posted

Just a thought but where it has been modified at the rear are you going to run into clearance issues with the clutch master cylinder?

Any reason you need this over the std plenum? I have the std one on mine and it works fine at just under 400rwkw, the enlarged opening will kill off some of the response but it really depends on what you are after.

noone Experienced

noone

Posted
  • Author
Posted (edited)

Dont think clearance will be an issue, touch wood!

"Need this" na not really I spose but

figured with the ceramic coating and potential for extra flow

it wouldnt hurt ????????

And as stated dont believe I can flow test it without sending it down south

figure I could try it then possibly replace quicker than that!

Edited by noone
Adriano Grand Master

Adriano

Posted
Posted

Beigh that the problem with the stocker is too much flow and pressure banking up to the rear cylinder, i would think the modded one will be worse. Flow testing it wont really tell you much, only logging the individual cylinders afr/egt's will give the answer.

dazmo Proficient

dazmo

Posted
Posted

Hey noone can you elaborate a little further on the inherant flow problems of the stock plenum ???. Mate there are far to many GTR's with

400-450 AWKW including my own car and several others I have built all running the stnd plenum and it is definatly not a restriction. I would also recomend having it flow tested as I am sure it would not be to expensive to have the plenum shipped to a major city to have the the flow testing done. Just dont forget that there is a lot more to plenum design than just the size of the thing and i will garantee that the nismo design will definatly be a better design than a modified stnd design regardless of the size of the thing.

noone Experienced

noone

Posted
  • Author
Posted

Appreciate that and yeah makes sence since the rear two tend to run lean

thinking the step from 3.5 inch to 4 may help with this added turbulence et all

may be better sticking to the stocker but would wanna send it to ceramic coat, meaning more waiting?

logging individual pots would be nice other than heat gun on the dyno probly not easy though

and have ceramic coated the exhaust manifold to so may not show much??

?????????????

noone Experienced

noone

Posted
  • Author
Posted (edited)

yeah I was more thinking the rear two cylinders running leaner et all

but as stated this probly would make that worse??

despite even flow on a flowbench etc

Ya can definitly make good power with the stocker wont argue that !!!!

I am starting to think it may be wasted cash????

Edited by noone
noone Experienced

noone

Posted
  • Author
Posted (edited)

Ya maybe but I cant help thinking it may be worth a try despite it bein kinda awkward to change out once in the car

think maybe the slightly expanded plenum size is worth it

I guess other than back to back testing it really would be hard to say?

Edited by noone
unique1 Mentor

unique1

Posted
Posted

i run individual egts in each exhuast manifold runner and cylinders 5 and 6 are not the hottest by a longshot on boost, only offboost, so i doubt very much they are the leanest. Im talking a 50 degree + in other cylinders compared to 5 and 6. This is with a stock 26 plenum and between 420 and 450rwkw. This is the same results on a friends car running a different turbo setup and motor combo but also stock plenum. I think this cylinder 6 is the leanest isnt indeed true when on boost, im sure when u let it idle down the plugs will show it is but thats because it is then not on boost.

thats my 2c worth from real world testing not internet hearsay.

STATUS Grand Master

STATUS

Posted
Posted (edited)
i run individual egts in each exhuast manifold runner and cylinders 5 and 6 are not the hottest by a longshot on boost, only offboost, so i doubt very much they are the leanest. Im talking a 50 degree + in other cylinders compared to 5 and 6. This is with a stock 26 plenum and between 420 and 450rwkw. This is the same results on a friends car running a different turbo setup and motor combo but also stock plenum. I think this cylinder 6 is the leanest isnt indeed true when on boost, im sure when u let it idle down the plugs will show it is but thats because it is then not on boost.

thats my 2c worth from real world testing not internet hearsay.

^^ agreed i swapped to the greddy plenum for a few reasons,hp was not one of them, contrary to the thought that 4" would be a backwards step Ive found no difference in "throttle lag" over the stocky.

Here are the latest cylinder balances done via egt for the greddy plenum @ 22psi. (430rwkw 630nm)

post-34927-1257516565_thumb.jpg

Edited by URAS
noone Experienced

noone

Posted
  • Author
Posted

Thanks for the input there guys, much appreciated!!

You seem to have some extremely cool tuning tools, EGT sensors are tapped to the runners?

would love to see some pics (big ask I know)

very interesting to here thoughts on response not being adversly effected,

Am trying out the gizzmo thermal gaskets too u guys are using them to yeah Trent?

Was planning on giving em a coat of hylomar to help sealing, would this be recomended?

Figure that plus ceramic coating of plenum gotta be worthwhile?

STATUS Grand Master

STATUS

Posted
Posted
Thanks for the input there guys, much appreciated!!

You seem to have some extremely cool tuning tools, EGT sensors are tapped to the runners?

would love to see some pics (big ask I know)

very interesting to here thoughts on response not being adversly effected,

Am trying out the gizzmo thermal gaskets too u guys are using them to yeah Trent?

Was planning on giving em a coat of hylomar to help sealing, would this be recomended?

Figure that plus ceramic coating of plenum gotta be worthwhile?

i run the gizzmo gaskets on all builds nowadays, i use ultra grey on both sides abeit very minimal so it cant be seen once assembled.

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