Waste Gate On Standard Manifold Vs Waste Gate On Turbo

[scotty nm35]

I'm not in the business of doing welding related fabrication work

Sorry, I thought you were by your statement.

Quote: And if any one wants their manifold to be done. The cost for doing so is $300 and our 50mm HPVA gates are $350 in additional.

The 430kw result was, for the 10th time, an RB25 in a 33gtst. The engine has cams and runs a gtx35 off an unmodified manifold, with a shitty 3 inch exhaust and a screamer on United e85. I have no idea where you got VQ from, mine is the highest output VQ25det I have heard of, and it's stuck at at 350kw due to the auto box.

[hypergear]

Sorry, I thought you were by your statement.

Quote: And if any one wants their manifold to be done. The cost for doing so is $300 and our 50mm HPVA gates are $350 in additional.

Means I do the engineering work, and supply the gate. You are doing the welding. Which is why I've been talking to you about making external gate running out of stock exhaust manifold, and I don't think there is more then $200 of welding involved.

Well, if that is a GTX3582 then that is a tinny amount of power. I still want to see the dyno paper.

[boostn0199]

Just because it 430 kw doesnt mean the manifold wasnt a restriction as if the person used the ssme setup with a proper manifold he would obviously net good gains with that turbo.

[Guilt-Toy]

The manifold of a Rb25det could be significantly different to a M35 Stagea which should be more modernised.

There is a 15 KWs gain just by swapping stock exhaust manifold to some thing properly made. The restriction on it is before the entry of the turbine housing, of where three collectors merges into one. By adding an additional collector at that point reduce excess heat, and pressure as what we can see in the change in upper power and torque curve.

The overall gain of this modification have made a difference of 31kws, with a final result of 376rwkws that is some thing that no one have ever made using turbine housing mounted external gate setups on standard Rb25det exhaust manifold. This is also my first attempt, there are few things that could be done improving upper rev range torque.

Scotty: it is probably worth while making a jig and properly fabricate stock RB exhaust manifold in similar manner to what I've done. With proper external gating setups, the factory exhaust manifold could be performing at same level as some of the popular aftermarket high mount setups.

so i would expect a 15kw gain from a external gate on the stock exhaust manifold? its a HKS2535

it would also help with the boost issues as well. it drops 5psi by rev limiter.

[jjman]

so i would expect a 15kw gain from a external gate on the stock exhaust manifold? its a HKS2535

it would also help with the boost issues as well. it drops 5psi by rev limiter.

people have done the external gate thing before on 2535's.

I think there is a bit to be gained but prob not worth the fking about unless you can do it urself. Its a small turbo which is going to struggle to flow much more air from that compressor wheel methinks... A good EBC and actuator gets the most out of the 2535 (had one myself. good little turbo )

[hypergear]

Looking back to my result, actually this external gate setup managed to match my Brae high mount manifold's result in exception of slightly lower in upper range torque.

G3's result which share the same compressor as the OP6 high flow.

http://www.skylinesaustralia.com/forums/topic/261613-hypergear-hiflow-service-continued/page-355

So this setup is enough to max out your 2535's compressor flow.

Scotty is coming over this weekend and we will be looking to get all the plumbings properly made and jigged, before offered as a cheap and effective service.

[mutex]

Before people get too excited by power gains hanging an external wastegate off the oem rb25 manifold.

Please note, it may be fine on the street, but on the track oem mani's tend to crack/warp eventually - done this twice so far.

Mind you if it ends up being a cheap welding mod, then it may work out ok.

Ps. If someone made a better steam pipe log living in that area using oem heat shield, this could be a great mod

[r34unit]

So what will make a turbo come on boost faster ? A manifold with smaller internal volume ?

[hypergear]

So what will make a turbo come on boost faster ? A manifold with smaller internal volume ?

Yes it does. Stock manifold has better down low response and torque using the same turbocharger.

Reference:

http://www.skylinesaustralia.com/forums/topic/261613-hypergear-hiflow-service-continued/page-298

[Weapon]

i prefer it on the housing... its the bottle neck.

This is my GT3582R setup bought from ETM.. nothing but issues and wouldn't control boost. If its plumbed into the right place on the housing should work but mine was obviously not in that basket. Granted mine is high mount blah blah not on a standard config. As soon as I changed to conventional gate of manifold configuration problem solved

[scotty nm35]

It is tapped off very late on the housing, well after the nozzle, still I would have expected it to work well enough, if the inside was cleaned up with a die grinder after welding. There have been no issues with boost control on any of the modified housings I have done, and no cracking on the mild cast, or investment cast stainless housings. Even after 5 years and countless track days.

I noticed you weren't running switched boost pressure to the top port of the wastegate, that will help hold massive boost if that's what you were planning...

[Weapon]

I had no need as I wasn't running an electronic boost controller so there was no need for a vac feed above the diaphragm. We eliminated all variables so it was just running gate pressure. took the .7 bar spring out and put a 1 bar spring in it, also tried vac feeds from the plenum and the compressor housing etc. Tried everything but the second it got to 4200rpm it would spike from 14psi straight past 35psi.

Every one of these I have seen done the waste gate feed has been different to mine. This was a kit supplied from ETM and I had no joy with it as I asked him what do you recommend and he said this configuration would give the best boost control however that was not the case I ended up selling the kit and moving on to another kit that worked wonders and never had an issue controlling boost.

[AngryRB]

Gate looks like its on a 90degree angle, probably why it didn't work.. if it were a half inch closer to the rocker cover it would of gave it the perfect entry to the gate..

Edited January 12, 2014 by AngryRB

[scotty nm35]

Gate looks like its on a 90degree angle, probably why it didn't work.. if it were a half inch closer to the rocker cover it would of gave it the perfect entry to the gate..

Agreed, in that position it would almost flow backwards from the gate, similar to a paint spray gun.

[GTSBoy]

Once gas has already accelerated to high velocity (such as in or after the nozzle in a turbine housing) it is much harder to make it change direction. Plus, the static pressure (or at least a good chunk of it) has been converted to dynamic pressure 9velocity) and there isnt actually any driving force left to make a 90° direction change. If you want it to turn 90° you have to do it while the gas is still as slow as possible.

[Weapon]

Exactly why I binned the kit. Had nothing but issues with it from the day I bought it.

This is a mod a mate of mine is doing to his Ti R31 Skyline. GTX45 with Tial Rear housing, Tial 60mm gate and also a built RB30 single cam. He hacked into a $2700 rear housing as he couldn't plumb it from his manifold due to a 5 inch dump lol so had to go off the housing

[scotty nm35]

That looks much better.

The stainless housings are great to weld, but damn they give the die grinder a hard time.

[Weapon]

Yea it should work a lot better than mine. I was still grimacing when he hacked into a near $3000 housing though haha

[scotty nm35]

I bet you could buy one for one tenth that if you shopped around.

[Weapon]

he got it at cost price locally as he buys a lot of gear and a lot of GTX's through there. The turbo itself wasn't horrible but just sheer size of the GTX45 housing is what killed the wallet.

He has bought a mixture of GTX3071 and GTX3076's for various projects of his and the Tial rear housings were very reasonable. But this one was a killer lol