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Discussion Starter #1
Planning a turbo swap over the winter guys.
Going from stock units (tired and smoking), to a set of HKS Low Mounts, a bolt-on pair...possibly 2530 or 2540's.

My question is, for a bolt on set of turbo's, are gains sufficient enough to warrant swapping the manifolds at the same time to uprated units?

I have bad experiences with cracked manifolds, ranging from cheap units (Stone Racing) to HKS and Trust units cracking... I would prefer to keep stock units, but how bad are they on the RB26?

What are everyone's thoughts?
 

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I am seriously considering the Tomei expreme manifolds when I change turbo's. Heard they are the dogs and are VERY robust not like some of the cheaper alternatives.

TT
 

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Spend your money on better things.......the standard manifolds are better then people think!
 

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i have a pair of the tomie maifolds and they are the dogs , they are a bigger bore than the standard manifolds but im sure you can achive the same results by porting the standard manifolds?
 

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People should REALLY look at GrpA homologation rules, they make it plainly obvious what parts are really good, as they the parts that wasnt allowed to be changed, they were the homologated parts.

Anything in that list is good for 650bhp with no real issues.

Crank, rods, intercooler, inlet and EXHAUST manifolds, to name a few...

These things can be modded, but physically look the same.

So basically, the std exhaust manifolds are decent, tho porting em cant be a bad thing.

If you ever seen one off the car, youd see, they suprisingly good!
 

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People should REALLY look at GrpA homologation rules, they make it plainly obvious what parts are really good, as they the parts that wasnt allowed to be changed, they were the homologated parts.

Anything in that list is good for 650bhp with no real issues.

Crank, rods, intercooler, inlet and EXHAUST manifolds, to name a few...

These things can be modded, but physically look the same.

So basically, the std exhaust manifolds are decent, tho porting em cant be a bad thing.

If you ever seen one off the car, youd see, they suprisingly good!
The only problem with that argunment is that the N1 manifolds (homologated) are different to the standard 05U ones.

I reckon the N1 manifolds would be the dogs...but are too expensive, so I went for Tomei manifolds.
 

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I think the only significant difference is the outlet shape, it is less restrictive. You can port the non-N1s to be just about as good I have heard. The cast material of the N1's is different also, but that should not influence flow.
 

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So basically, the std exhaust manifolds are decent, tho porting em cant be a bad thing.

If you ever seen one off the car, youd see, they suprisingly good!
I thought they looked surprisingly average , with surprisingly thin wall thickness where you most need to remove material .

Although TBH flowing enough air for twice the standard hp on many cars , they must be fairly good .
 

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Hi Loz

Saw you and motor running at the Pod, low 12 I think?

I don't think you can go wrong with 2530's on stock manifolds, plenty of power for a low 11 pass and excellent for track.

2540's are not realy suited to the 2.6 IMO, a bit too laggy for the slight top end benefit over the 2530.
 

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Discussion Starter #11
Hi Pete,

Cool mate, didn't realise you were there mate.
Ran a 12.7 on the stock turbo's, had problems with car all weekend, didn't really have chance to prep the car, just tried to grab a base time to see the future improvements of the car. Low 11's would be good enough for me, car won't be used much for drag as I'm not ready to plough money into the transmission yet.

GT2530's were my preference, just noticed a few sets of 2540's hanging around for decent money and thought might work OK with RB26 maybe up until money allows a larger displacement.

2530's on stock manifolds, perhaps open the ports on manifold out a little then, a little on exit also? Sounds like a nice cost effective option for people who want 600 region.

At what stage (bhp wise) will uprated manifolds be needed ? Anything beyond 650(fly)?
 

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Most people I know running stock manifolds with 2540's struggle to get below high 11's, similar specs with 2530's and GTSS's have produced low 11's.

As I know you are working on a tight budget I would say that your money would be better spent upgrading the fuel lines and fuel system rather than manifolds, the 32 has a fairly small fuel line and that will cap your potential power before the manifolds would.
 

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Discussion Starter #13
Thanks Pete.
I've not been able to find much literature on the 2540's to be fair, and 2530's always seemed to produce good results on circuit etc, I'd just perhaps want turbos that could run O.K (fun/streetable) on 2.6 but better on 2.7/2.8 when funds allow, to save swapping again once new bottom end.

Manifold Wise, I now feel confident in the OEM Manifolds, staying well below the 650bhp mark (but want excellent Torque), very handy as like you said mate, I'm on a tight budget for everything.

Will see what material needs taking out, will get a hand with it and see about using some coating or wrap.

Re: Fueling.
Thanks for your advice mate, I remember Jon having problems with his Stock Lines?
My fuel feed lines will be replaced for larger bore and stronger lines once all my fuelling bits have been bought. Got Uprated Lifter Pump, still got my Bosch 044 from my red one, Just a case of getting everything together; Surge Tank, Fittings, Lines, Hardware for Mounting External Pump, Large External Filter, Voltage Amplifier, Fuel Pressure Gauge, SARD AdjFPR...Not Cheap!


I'm also trying to help a friend to start doing some research into Custom Turbo Kits (plans to release UK Based Bolt On Turbo Kits) to see what people expect from the stock manifolds, what is actually being achieved and where (in terms of power level) people expect to start looking at/needing aftermarket manifolds, so looking at what is popular at the moment, in attempt to start working out popular packages for various levels of tune...

Would still like to hear everyone's opinion on low mount turbo manifolds, what people are using, what has been used etc.

Stock R34

Stock R34


HKS GT2530/40 GTSS/RS Low Mounts


OBX (Budget) Low Mounts (Stock or Similar)


ESSENTIAL Low Mounts
 

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i would only go for tomie or hks on manifolds! i got a pair of none branded manifolds before my tomie ones and they were crap the holes in the flanges were to big and both flanges werent flat.
 

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the best advice i have on GTR manifolds is to keep the standard, firstly port match to the head and turbo's (most people use the gaskets to make it match) and then extrude hone which gives a perfectly smooth finish. the standard manifolds are more than capable of making good the numbers, without worrying about cracking, if you get realy excited you could ceramic coat them aswell. thats all im going to do when i get my pair of GT-SS
 

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the best advice i have on GTR manifolds is to keep the standard, firstly port match to the head and turbo's (most people use the gaskets to make it match) and then extrude hone which gives a perfectly smooth finish. the standard manifolds are more than capable of making good the numbers, without worrying about cracking, if you get realy excited you could ceramic coat them aswell. thats all im going to do when i get my pair of GT-SS
OEM manifolds crack if you port match the turbine outlet...there isn't enough meat there
 
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