Ebay Plenum For Rb26

[Rbdirty30]

So I've noticed on eBay there's a few greddy 6 throttle body's intake plenum replicas on ebay, now the greddy is around the $1100 mark and the eBay jobs are around $300 to $500 but still boast of decent power gains. Has anyone brought a eBay special and noticed the gains with there rb26? Or had any troubles with them?Or is it best to stay with the original intake?

[(OO)SKYLINE(OO)]

Wouldn't bother, decent power gains can be made with the original intake / throttle body.

[Rbdirty30]

I've read up that the standard intake apparently leans out number 6 cylinder tho?

[scotty nm35]

Who's to say the Ebay one won't also?

Have you checked this theory by measuring the egt's in each runner, or are you just happy to quote old wives tales? Gibson didn't have any trouble with it afaik...

[Rbdirty30]

I'm just asking questions to find out if it's worth while or not. I'm no mechanic and trying to find these things out on google is hard if not to no answer at all. That's why I've tyres to the forum to hopefully find someone that has done this and that may help me out

[scotty nm35]

People do all kinds of stupid things, that doesn't mean you should copy them...

I have seen 500kw through a factory setup, intercooler, plenum, manifolds, piping, airbox, fuel lines etc. If you are near that I would be more worried about the block splitting than the runner flow. Just run a fat mixture and cram some more boost in.

[GTRPSI]

Just to help the OP, ive got a genuine Greddy and had a ebay/china copy side by side.

You had to look really hard to spot the differences, runners, diameters, everything identical, slight differences in casting lines...very slight.

Would come down to the quality of the alloy IMHO.

Ive met and spoken with a Chinese manufacturer that makes them, as he said to me with any part, supply me with the brand name original and ill copy it for a fraction of the price and you wont tell the difference.

And just to throw a spanner into the works, he was offering them to me for $US 80 dollars each 2-3 years ago, no wonder there are so many copies out there......

[Odium]

Would come down to the quality of the alloy IMHO.

This... And how it's actually made. You can have the same materials, same design (making a mould isn't hard) and still stuff it up by having the casting temperatures or cooling speed all wrong. End up with a brittle part of the product which will be the first to crack under a high load.

Personally, I wouldn't want anything potentially breaking off a scraggy bit of metal under high temp / pressure and going straight into my engine. So if you go for a cheap copy get it checked out with a scope and cleaned up before it goes near the car.

[(OO)SKYLINE(OO)]

I've read up that the standard intake apparently leans out number 6 cylinder tho?

Where did you read that?

How much power are you wanting for you to change your intake plenum?

[Rbdirty30]

I'm building my motor ATM to have around 450 to 500kw

[Rbdirty30]

I found a few forums searches off google saying that they lean number 6 , thought I'd ask before I finished my motor because it would be easier to change a manifold whilst it's out. I'm thinking I might buy the greddy/trust manifold for peice of mind

[Anfanee]

Lol you want 500kw and look to save money on something like that?

Nikminute parting out another GTR that broke itself.

Do it properly

[Rbdirty30]

It's not about saving money I was more getting at about the differences and if it's worth spending the extra if the eBay manifolds are as equal quality becsuse they look identical in pictures

[Sinista32]

Re cylinder 6 - true. Although tuned around.

Stock plenum is awesome and you will have no issues so keep it. Don't waste your money on these for the RB26

In my opinion the best is the Nismo Plenum - max 2-4% improvement - EDITED: 1-2% power and 0.4% fuel saving - SUBJECTIVE. Yes I have one

At $1500-$2000 money is spent better elsewhere.

Topic covered heaps already

Edited June 11, 2014 by Sinista32

[(OO)SKYLINE(OO)]

I'm building my motor ATM to have around 450 to 500kw

I found a few forums searches off google saying that they lean number 6 , thought I'd ask before I finished my motor because it would be easier to change a manifold whilst it's out. I'm thinking I might buy the greddy/trust manifold for peice of mind

I see.

Well I'd double check with Racepace, just give them a call to confirm.

As I have said before, you can get decent power gains with the stock Inlet Plenum but how much to what point, I'd double check.

So yeah, don't go throwing your money on ebay parts.

[Rbdirty30]

Thanks for your help guys ,much appreciated!

[GTRPSI]

I noticed your user name and that you had a R32 GTR, so im assuming your doing a RB30 bottom end?

If so, before you go any further, the Greddy plenum will hit your clutch master, there are work arounds, or a few ways to do it but if your only going to 500Kw you may as well stay with the factory item, it does still work well.

Yes 6 can lean out, or run leaner, quick cheap way is get your injectors flow tested and put the highest flowing one on number 6.

Otherwise 6 EGT probes on the manifold will do the trick......as will getting the tuner to run injector 6 a little longer.

Edited June 12, 2014 by GTRPSI

[Rbdirty30]

Yeah mate I'm halfway through building a 26/30. Can the stock manifold be port match to the head or is it already done from factory? Also is there threads on how to fix the greddy manifold with the clutch master cylinder touching?

[GTRPSI]

There are a few threads, all with different suggestions/methods in the RB30 section.

From using spacers under the cross member to steering shaft spacers to cutting the bonnet, some even remove the clutch booster and use a different clutch slave with spacer.

We are doing the same build right now for our 26/30 R32 GTR.

Edit, Forgot to add, port matching always helps, all depends on how far you are going or are prepared to look at details.

Edited June 14, 2014 by GTRPSI

[Rbdirty30]

I've had the 30 bottom end in my GTR before but I never went crazy on the head. My n1 pump let go so I'm spending abit more this time. But all I did was cut the inner braces out of the bonnet and tapped the floor up abit with a hammer near the low mount dumps for clearance. Everything else was sweet. Well I've got an aluminium die grinder bit so I better port match it