How do these manifolds look!!!

[Waldo]

just wondering how all you guys (and girls) would think this manifold would flow compared to the stock rb20 unit, i have a gcg hi-flow job on the engine so just wondering if you people thinks its worth gettin for a bit more spool up time

[Cubes]

Its a crap setup.

You can see for your self, look the size of the pipe where they merge.

Port 3 will have higher reversion than the rest. All of which is not good for good reliable power.

You get what you pay for. A tuned length exh. manifold is theoretically the best option as you get equal reversion across all cylinders.

HKS do a good cast manifold for the RB, obviously a bigger turbo and the manifold has provision for an external gate BUT it does show the difference in design where the exhaust runners meet.

The short the runners the better response you are supposed to get with regards to spool. This would suggest to me that a tuned length manifold may actually increase spool time slightly. It also depends on pipe id as this affects the gas velocity.

Thats my view by simply looking at its design.

It really needs to be flowed to see how well it works.

[Waldo]

would you notice any power differance with the hks manifold over the stock in my situation

[Waldo]

does having the external wastegate flange on the manifold effect the way the gas would flow if you were to use a internal gate turbo

[Cubes]

It 'should' unlock a little more top end and average power.

Spool time etc really is a hard one.

Many people do not notice a difference in spool.

A friend of mine was making 306rwkw with a stock exh. manifold and a GT35R turbo.

He switch to a aftermarket manifold (unsure if it was tuned length) slaped on a genuine GT35R exhaust a/r and didn't notice any difference in spool or boost build time. BUT there was an increase in total outright power, It picked up 20rwkw by simply going a good exhaust manifold and properly designed (not machined) exhaust housing.

So its really hard to say exactly what created the extra 20rwkw. Was it the exhaust housing or the exhaust manifold. Probably a little of both.

I'm keeping the stock exhaust manifold for up to 300rwkw. However it will be power ported.

I really don't see the need in changing the stock exh. manifold for the power I want. Especially with the defects over here in SA.

Shortest possible route to the turbo.

I would go the HKS manifold if I were required to. Rig up a nice exhaust shield or possibly modify the stock one and it would be hidden and stock looking.

[Cubes]

does having the external wastegate flange on the manifold effect the way the gas would flow if you were to use a internal gate turbo

No.. What happens when the wastegate is shut?? It acts as if the flange is blocked off.

These manifolds can be picked up as low as $450 to $900.

I'm not 100% sure if it is exactly the stock mounting position. It doesn't look so but very close.

[dangerous_daveo]

Dude its arse. I personally wouldnt waste my money on an exaust manifold with just a highflow unless its a race car and thats what your limited to, and you need every little edge you can get.

That money could be spent much better else where. Say an ECU, or say some new cds or something...

The only time I can see an aftermarket manifold coming in to play is when the turbo doesnt bolt on, or its a big sucker and you have the money to spend to get a nice tuned lenght manifold that will pulse to bring the turbo up on boost that tad quicker. But by that stage you have probably done a hell of a lot of other things to the car.

[R31 POWER]

I have one of those manifolds that Waldo has pictured.

Dyno graph http://www.users.bigpond.net.au/r31power/251hp.jpg

Not a full on tune but it has one.With the HKS GT2535 boost comes on hard @4000rpm.12psi is made @3500rpm in most gears.I have noticed that the exhaust note is very meaty.

[Cubes]

Nothing quite like the sound of extractors or a tubular exhaust manifold.

R31 Power, Its a pitty you weren't able to get a before after run.

What it looks like and the way it performs may be totally different.

Did the turbo and manifold go on as one? Reason being is I'm curious if it made any difference to off boost torque.

[R31 POWER]

Someone i know had probs with big boost but was making low power with this manifold.He did some other stuff and put the stock mani back on with a external gate wich made more power.So yer not sure what was the power zapper,tune,mani or butterflies in the plenum(reb top RB20)

[R31 POWER]

Yes both went on at the same time.I got the manifold for $500 I think so i thought stuff it, it has to unlock a few horses.25 box is going in next week then I'll get it tuned.If it does'nt make the goods I'll put the stock mani back on and get it tuned agian.

When I drove it for the first time(with standard ecu,bosch 040 pump)I'm sure it pulled a little better off boost.Even with the tune it has now it blows black shit coz it's way to rich.

I had a plenum leak and a pin hole in the cooler piping when it got tuned so that would'nt of helped it,fixed now.I'm hoping the next tune will make me happy.

[Cubes]

To determine if the manifold made off boost a little better you really need to have the same turbo before and after.

Reason being is I tried a larger turbo on my rb20det which both made the exhaust note angrier and off boost torque was noticably up.

I put it down to the exhaust housing flowing just that bit easier.

[R31 POWER]

I thought the same.I did lots of things at once so I'll never know what did what.I went from a supra fmic to a GTR cooler with 2.5inch piping, exh manifold,040 and hks turbs.I just want power

I'll keep you all posted on how the tune goes.

[bigcarl]

waldo ive got the same manifold that you have pictured, i also had a gcg st.1 450hp turbo attached to it . i have dyno sheets for before and after it was fitted. 1 was running at 212rwkws with the standard manifold at 17psi , then added the manifold you have pictured and power went to 224 rwkws at the same boost. i picked up the manifold for $560 on the for sale section of these forums and now run it with my internal wastegated gt30 500hp turbo. power now is 260rwkws at 20psi and i running standard engine with stock head and cams. hope this helps you to decide. if i could have got my hands on a 6 into 1 tubular manifold that had no provision for a external wastegate then i would have bought one , yes they do flow beeter but i also know of another skyline that has same turbo as mine with one that only produces another 5 rwkws than mine. id probably get more of a gain by changing to after market cams or changing exhaust housings from a/r .63 to a/r .83. theres my 2 cents worth . feel free to pm me if you need anymore info cheers.

[Waldo]

well that makes life a bit easier someone that actually can tell me what it will do to my power

cheers

[Waldo]

how does the car run with the manifold? like does it ever splutter at high revs or anything that is noticable, i dont want to buy one because you told me about your luck with power gains and it makes my car run shit. lol

cheers again

[Cubes]

bigcarl,

RB20DET or RB25DET?

[chowetime]

I am very new to the world of boost so please excuss me for my mistakes... i was under the impression that if all the exhaust outlets on the manifold were the same length it would equal to a better low end of torque response ( less turbo lag) due to equal flow distances and pressure....

[bigcarl]

cubes , its a rb25det. power is smoother , spools a little better , more mid range and top end and of course a really nice exhaust note when your reving the bags out of it. i think that equal length runners 6 into 1 would definately be the ants pants but they are hard to come by. thios manifold actually seems to scavenge the exhaust gases really well for low to mid range and a bit more up top. for $560 who could argue. before i put it on the max boost i could run before detonation was 17.5psi , with it on i could run 20psi . but then my stock coils packs began to break down. upgraded to splitfires after i changed to gt30 so i cant tell you what the peak power reading was, but more power in the midrange. if you want to see the dynograph i can send it to you?

[Trust33]

Heres a thought.Buy some cams,keep the stock mani,and make uber low-mid range with the hi flow.Yaaa!

I doubt that the aftermarket mani could keep up with the bang factor of cams.