I was talking to a fellow HT member on AIM and since we both have the GReddy Kits (18G) we were talking about a 2.5" or 3" Downpipe, High Flow cat and Cat back exhaust. Now with an internally wastegated turbo and high boost you have to be aware of possible boost spikes with this setup and a 3" exhaust system (downpipe, cat, etc).

Now you have one of two things to do from this .. here is what he sent me ..

This particular situation is caused by inadequate volume of the wastegate opening. The hole on the turbine is too small to let enough exhaust gasses bypass the turbine, thus causing the turbine to continue spinning faster. You can do one of two things. You can port out the turbine housing where the internal wastegate is and have a bigger "flapper" installed, thus increasing the volume, or you can weld that shut and upgrade to an external wastegate. No boost controller will solve this problem.

My question is, if you wanted to weld the 18G WG shut, okay cool, but where the heck would you add a external WG, like a 35mm Tial, on the manifold? The GReddy Manifold is heavy cast iron, so I would assume youd have to drill/port a hole from there? hmmm this isn't soemthing id use my little dremel on.

What do you guys think? This all started cause im thinking of getting the same high flow cat as him, 2.5", but then the 3" came up and all this started

 

That was said by tony1 on another forum that I just showed to him...

 

I'm sure Art, Chris or Joe will have a good answer

 

anyone???

 

i think you have to go to a new manifold. i dont know of one that exists.

and why weld the WG shut, you can just keep the WG flap closed by locking the arm into place. no? and you'd be welding cast iron or steel (not sure what turbine housing is) to inconel (the flap material) or some other metal.

i am considering porting my WG but i can tell you now its a risky proposition. it might not be able to be ported enough and there is not enough room to install a larger flapper. TRE makes a 34mm one for about $30 but they offered to make a custom one since the 34mm one wont fit apparently.

however, their info was based on the TD05H-18g that they worked on from a MR2 turbo. our turbine housings maybe be different. (?)

either way. lemme know if you're exploring external wastegate. I have no idea how you'd do it. mean time I am going to pull the turbo soon and see what can be done by way of WG porting. I might work with tony to have mine ported and we'll see how that goes. Maybe we can get TRE to make a small run of non-circular flaps or just smaller ones 28-32mm or something.

Fredo and all the greddy folks, lets keep eachother informed on this stuff.

edit - also see my comments here https://honda-tech.com/zerothread?id=362718

 

I thought about doing the same thing. Modifiying the Greddy manifold to accept a wastegate is not the best idea. Although you can weld a flange to the manifold, it becomes brittle and prone to cracking. Purchasing a new mani would be the best solution but the mose expensive also.
Does anyone make a turbo manifold that fits the TD05H-18? What about an adapter to mate with like a rev-hard manifold. I also thought about porting the manifold to get rid of the divider. Ideas??

 

my biggest concern on my greddy kit is the O2 housing, it way to smalle IMO, and wouldn't support a larger DP very well. i had one made, but it is kinda ghetto, i mean, the work is good yeah, but it's was shitty how we had to make it work.

GReddy makes a few upgraded internal wastegates, i am going to be getting the 14lb WG, but i would like to port ot the opening and use a larger door if i can find one

 

What I don't understand is, why isn't there someone out there jumping on the opportunity to get a shitload of sales making better manifolds compatible with Greddy? I made a suggestion to Geoff at fullrace to make such a manifold and he didn't respond. Aren't there more Greddy kits out there than any other? Why won't someone do this?

In my opinion, if you're going to modify the wastegate, you might as well weld the thing shut.

 

thats news to me. i thought drag and revhard have been historically more popular for honda.


are you saying dont bother porting the internal wastegate at all? or are you saying IF you go with external WG to get it welded closed? i dont like the idea of welding cast parts. especially when subjected to this much heat. yeah holding the port shut isin't permanent, but its undoable easily. the WG port will stay shut if you just disconnect the WG vacuum source.

 

It wasn't a statement, it was a question. That's why I used this ?

I'm saying that if given the choice between porting the wastegate, or welding it shut and using and external, I'd go for the external. So you're saying that it's possible to keep the turbo unmodified, disconnect the vacuum line and use a new manifold with external wastegate (if available of course), and that welding is unnecessary? If this is true, that would be the best option.

 

it looked like a question implying you knew what you were saying. my mistake.


that sounds complicated and likely to risk the integrity of the greddy manifold.

yeah i think the WG will stay closed if you disconnect the hose to it. but i dont see where you're going to install an external WG. soooo i'm back to porting the internal...or...just bailing.

 

Fred, i dont mean to hate on you or anyone with the GReddy kit, but if you desire to do all this, why didnt you just go with a set up that called for an external wastegate to begin with?

 

i went with greddy for a higher quality kit, easier to install, and internal wastegate is appealing from an emissions and reliability standpoint.

i still prefer it.

 

There are plenty of other things to modify on my car before the wastegate. It's just good to know these things for future reference.

 

I'll have to quote Joe i went with greddy for a higher quality kit, easier to install, and internal wastegate is appealing from an emissions and reliability standpoint.
i still prefer it.


It was just a question I was thinking about etc, I know what you mean, I guess its a pitfall of a internally WG'ed turbo, no biggy tho, we all are smarter now

 

you wanna know my dumb reason for a GReddy kit, the internal WG was appealing to me b/c i have a predator hood, and i was afraid an external WG wouldn't clear the hood vents....

 

I think your answer may lie in the hands of DSM owners. A custom "shitgate" style 02 housing may be what you are looking for. i.e. the internal gate has its own outlet on the flange with an external wastegate attached. You could then plumb the gate back into the downpipe further downstream, increasing power while eliminating spiking. Take a look. http://www.forcedperformance.net/ima.../custom_o2.jpg
Hope this helps.

 

damn, that's pretty sweet..... to bad it would interfere with my PS and A/C (no offense to you Jalopy)

 

more thoughts?

 

the more i look at that DSM setup, the more i think i might try to make that work.... i like that idea, and i think i figured out how i can make it work for me

 

I think the hardest part of that setup would be machining some type of flange to weld the piping to. Nothing a good machine shop can't handle. My brother will be doing this this summer, BTW, on his D16 setup. Should gain some nice power. His will retain the internal gate, closed loop. 3" turbo-back exhaust. If you get funky on the piping, I think you can still retain A/C... anyone wanna start making flanges?

 

Back from the dead , but has there been any new manifolds made yet from internal to extrenal? Or even a custom one for the 18g turbo?

Falcon did you ever port your wastegate hole and put a bigger flapper? Hows the boost holding?

 

I would like too know too.

Also does somebody have a link to the picture posted above? The one with the DSM setup.

 

I'm running a 2.5-3" DP made by b18flip...no cat, 3" exhaust. I don't get any spiking and I'm currently running 12psi. Manual boost controller to put the boost up...other than that, nothing to limit the boost at all.

 

I'm running a 3" dp, with 3" thermal, and an AVC-R set to about 10psi. It creeps up to 15psi before hitting boost cut with the hondata. I need to do something about this. I can't floor my car to redline because of this. Does the flapper upgrade work, or not? I've been also toying with the idea of putting a resonator in my thermal to quiet it down some. Maybe the litttle bit of backpressure combined with the larger flapper will fix it. Opinions? If not, I'm not going to have a wastegate welded to my manifold since the generel opinion is that it will crack. I'll just go back down to 2.5" exhaust. All on the stock block, btw. Thank God for J&S.