Its common to use dual wastegates on the 2 rotor because it makes the fabrication easier. The dual wastegate trend started a few years ago because any average schmuck with some fabrication skills (in many cases dreadful fabrication skills) would offer a garbage manifold and the boost couldn't be controlled. And to be honest a few of these unskilled fabricators were mentioned right in this thread.

A properly designed manifold does not need dual wastegates.
i was using single 50mm wastegates on plenty of setups (t78 t04z efr8374 and many more) and with the boost control off it was the same as the spring pressure. Maybe 1 psi difference because my wg is routed in the exhaust

it doesn’t appear that you know what you want from the setup you are trying to piece together and thats making your selection difficult.
do you want to have instantaneous response like the twins?
Do you want to make a million hp?
what is the application? Street? Track? Drag? Hill climb?

make a plan how you want the car to behave and the rest will fall in place ( with small variations and options)

and for what its worth, i would personally avoid the vband manifold

 

According to their website, they have a cut line identified for a 60mm wastegate.

Would like to see more photos of the Artec. Its impossible to get a perfect manifold. Looks like the front runner is much shorter. Dont know how significant the equal length runners would be.

 

if that were true you would be doing it without asking questions on a forum, much less arguing against answers that weren’t what you wanted to hear. Like not wanting to use a 50mm WG that clearly has good bias built into it. You won’t be happy until until somebody says use a 60mm.

so ok, cut the 50mm flange off and use a 60mm instead then. HTHs …
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Absolutely nowhere was I arguing against answers given in this thread, I understand reading comprehension is a lost skill in modern society but man is it so depressing to be reminded of how much people lack it on a daily basis. I stated multiple times I have wanted a 60mm wastegate simply for the similar performance of 2 44mm gates and that I AM OPEN TO A 50MM GATE IF A 60M ISN'T NESSECARY, aka if its overkill.

"​​​​​​​if that were true you would be doing it without asking questions on a forum"

Once again reading comprehension, if you read above I clearly stated I simply came to this thread to see if anyone had any REAL WORLD EXPERIENCE with a few different manifolds as I prefer to hear opinions of users of products before I simply blindly buy it.

 

As someone said above, 50mm is fine if there is decent wastegate priority. Look how small a wastegate can be when it's got good priory like internal wastegates.

 

Thank you for the insight on the dual wastegate situation, I simply put my trust in people that are much better fabricators than i am so when i see so many of said individuals making dual wastegate manifolds i figured they know best and it must be a necessity, especially from large companies such as Turblown.
Im not sure how you came to the conclusion that "it doesn’t appear that you know what you want from the setup you are trying to piece together and that's making your selection difficult" but unfortunately i know EXACTLY what i want and that is what makes my selection difficult. As stated before i am aiming for the 500hp mark, only want a single gate, will be using a G35-1050 and will be doing 50/50 street track, is also want the vband manifold as I want the peace of mind of not having to deal with the gasket leaking, RTV'ing/gasket maker every time I remove the turbo and also the ease of removal and installation that you get with the vband. Also, turbo technology is moving towards vbands anyway so if I am going to change my manifold absolutely no reason to not get a vband.

 

Appreciate it, never was opposed to a 50mm just figured the 60mm would be necessary to overcome the poor runner setup of the Vinny Fab manifold and wanted to hear people's opinions on a single 50mm, with the newly released Artec is appears to be much more efficiently designed.

 

Rtv or gasket maker on the turbo? Start using quality gaskets and quality manifolds and that “problem” disappears.

how often are you planning on removing the turbo and for what reason? In the last decade i changed a whole bunch of turbos and this was never an issue, for me at least. Maybe your use will be a lot more hardcore than mine and you would need to do that more than others? Who knows!

no the turbo technology is not moving towards the vband turbos even though there are some more options nowadays. If that was the case why didnt tial continue producing the vband housing for the borg warner 80mm turbos? I do have one here as a matter of fact in a collaboration i did with tial.

i still dont think you know what you want. I suppose you want the 500 hp because maybe it sounds cool?
i am not trying to insult you by saying this sorry if it sounds like that

 

Well at my current rate I'm pulling my motor/trans out once a season to tweak my setup and make small changes, so yes for me personally the vband, although inconsequential to you, would provide me with just that slight amount of less headache.
Obviously, you feel differently but from the opinions of many people and the actions of companies I've seen, it appears that vband is the way things are going with companies like garret pushing vband housings and more manifold producers focusing on vband offerings.
And I guess to answer your last point I specifically want to aim for 500hp as I've heard from a lot of owners that the 500 mark is the sweet spot for the FD and going much over that for a car driven on the street isn't much fun, now my car only makes barely over 400 right now so I can't confirm this for myself but I'm not sure why you would chastising me on that point when i cant specifically tell you the 500hp mark is perfect for me until I do it? That would also leave me with a power-to-weight ratio of around 5.5 and although every chassis is different, many people say 5.5 is a fun "sweet spot" as well.

 

Not at all chastising you but your response perfectly explains your thought process.
best of luck in your pursuit of the “sweet” spot

 

Ive made it painfully clear I am hear to learn, I know what I want but I obviously don't know everything so I always want to learn, so can you please explain as to why me saying following others' recommendation of a 500hp "sweet spot" is so appalling to you, once again, I'm here to learn but all you condescending replies have consisted of your opinion with no reasoning to back it up. "If I were you wouldn't go with a vband manifold", and now obviously you have a problem with someone wanting 500hp but haven not expressed why, so if there is a massive issue with that I'm just not aware of I'm totally open to learning why is shouldn't want to aim for that number? Obviously, you're not obligated to respond but just pointing out how you are coming off.

 

No one said you shouldn’t aim for a certain number. Aim for whatever you want; at the end of the day its your car and your money. Believe it or not i am happy when there are success stories even from people i dont know.
I don’t have a problem with you or your goals. This is the first time i am seeing your posts so why would i have any sort of issue with you?

my goals are way past the 500hp and i have successfully reached my set goals multiple times. So i am not the one to say that 500hp is not reasonable or not achievable.
on the contrary; 500 hp was not enough for me for the use i am putting my car through.
But in many cases 500 hp is not enough and in others 500 is far too much. It all comes down to what the purpose of the car is. Realistically speaking an xxx hp figure means absolutely nothing. 2 setups both making 500hp can have a completely different behavior


all i am telling you is to figure out on how you want the car to behave and dont worry about the hp figures. You figured out the math for the perfect setup so you are set. it seems that your mind is set so it doesn’t matter what i or others will say

But to answer your question about the vband manifolds. i have used vband manifolds before(off the shelf and custom) and the ease of assembly did not make up for the response loss.i mean i have a couple of them sitting here Lol

i have no desire to get in a pissing match with you or with anyone else and more frequently than not I wonder why i bother posting here

 

Like I said, no desire to get into a "pissing match" from my end as well, just feel like its a waste of my time and yours to post on threads telling people they are wrong or don't know what they are talking about if you don't at least explain why, then I can at least learn something from it you feel me?
Ive actually read through your build thread before so I know your goals and capabilities are far beyond what I'm looking to do, and recently revisited your build thread as I have been trying to find some 1/2 fenders liners to cover the engine bay holes like the carbon ones on your car and also have been looking into a RE gt wing and i saw at one point you had gotten some legs and were looking to design a plate that fits up to the stock holes (I'm assuming that never came to fruition?).
Ultimately I agree with you regarding the response, I've heard that vbands flow better but are slightly worse response wise but I was hoping at the power level I'm aiming for and the turbo size I'm looking to use it would be marginal, I'm assuming for your power level running the EFR 9280 at 28 PSI it's much more apparent.
Anyway I apologize for any harshness in my responses and appreciate the help, keep your thread updated I enjoy seeing someone do all the things I want to do on my projects but don't have the capabilities to accomplish

 

I did not once say you were wrong or that you didnt know what you are talking about.
i said you dont know what you want because a 500hp time attack car and a 500hp drag car are 2 completely different build processes and completely different behaviors. A power figure by itself means nothing.

if this offended you I apologize . But in order to build a car successfully you need to know how it will be used and then you determine what parts you get. This was my message all along. And just so you know there’s plenty of garbage that it is marketed as good products. With that being said i think that an 8374,which was also recommended above, and i have used for many years is the ultimate turbo for a street car that often sees the track. I am not saying that the new Garrett G series are not up there either but i havent used any of them so i cant make a recommendation. Ever since i switched to the efr series i am not looking for anything else.i did use the older gt and gtx series and i cant say i wasnt happy with them but efr is a completely different ball game

thanks for the kind words on the build thread but i did end up with a different solution on the gt wing.

 

he thinks everyone else lacks comprehension you can’t make it up.

You just didn’t comprehend me gigging you a little. Unlike yourself I don’t get depressed in this kind of situation, I just make lemonade
.

 

At no point did you offend, me just trying to soak the maximum amount of info out of your responses, and trust me I understand the differences between different use cases for a car and to be fair I did say multiple times it's a 50/50 track street car although I will admit it's more like a 70/30 track/street car as I rarely have gotten to drive on the street, I guess the confusion came from me not specifying that I meant road course track not strip track, I have never once went to a drag strip so it honestly completely slipped my mind to specify haha.
I also find your glowing review of the EFR series interesting I definitely will have to give them some more thought, what would you say made them so much more appealing to you over Garret offerings as I've always been drawn to the new Garret G series due to how compact they are making them so versatile.

 

Well definitely not everyone just you in the case of this thread, was simply pointing out that the comment you made didn't really pertain to the situation as I hadn't been arguing OR waiting for someone to tell me what I wanted to hear, actually to the contrary.
Anyway as I said I might have come off a little too harsh but that wasn't my intention, I appreciate everyone's constructive input.

 

that’s teh intrawebz life bro, best wishes for whatever you decide.
.

 

on the dual vs single wastegate topic, maybe I missed it but I didn't see anyone mention that dual wastegates on a twin scroll manifold and turbo setup were developed to ensure the exhaust pulses are fully divided helping boost and transient response. Some single WG setups have used a divider for this as well.
Of course this doesn't matter on vband or other single scroll turbine housings; and the benefit may be null on newer, quick-response or smaller turbos.
Also remember the more boost you plan to run the less needed wastegate priority (flow priority and wg size) and viceversa.

 

There's a reason EFRs are so popular, specifically the internal gate. No more wastegate diaphragm issues, quieter to pass sound checks / decibel limits, the best spool for the size, wonderful transient response, literally Engineer For Racing. 8374 will get you to 500hp, 8474 will get you well past it. It's more expensive at first glance, but probably equally by the time you add in a BOV and twin wastegates.

If you're running at the track 70% of the time, are you really going to want less than 400hp? I imagine an 8374 IWG with an open wastegate would struggle to make 400 crank. It seems like you are looking for a reason to be different, which I respect, but at the same time: ask yourself, why is the EFR 8374 so popular, and do you have a really good reason to move away from a proven setup?

I sell carbon engine bay wheel covers. It's a few months wait, I have had way more interest than I anticipated, but people seem to love them.
https://www.rx7club.com/market/1159317

 

The draw for the EFRs as you said has always been the quiet exhaust, reliable wastegate, and great transient response which is obviously the biggest one for a track car, but EWG setups actually make more HP and generally have better boost control (reference picture from Turbosources website) which is why I had been planning to go garret this whole time, and in my experience, I've seen more people using G series turbos in the last 4-5 years than EFR by a lot so I didn't plan on being different but definitely don't mind it.
End of the day ill definitely reconsider an EFR off of your guy's input, always looking for tips on improving a setup. I will absolutely be hitting you up for those fender liners as well thank you for help fil that need in the community as you discovered its something a lot of people want not sure why i hasn't been done sooner?

 

your wheel covers look great indeed. I went with a different route on mine and i love them but only a handful of sets were made. Cant go wrong with your price, i did pay a lot more for mine

 

I was hoping to find some wheel arch covers just like yours with them being mounted inside the wheel well like a fender liner but like you said only a limited amount were made and it seems no one else makes some with that design at this time, other than that i enjoy supporting users here by buying their products and @mr2peak fitment and quality looks great from the pictures.

 

Thanks for the kind words.

The full liners are a much more complicated part, larger so harder to ship, etc. Probably why they are no longer made.

As for the EFR making more power EWG, yes it will. But what if you just stepped up a size? Anyone know what the spool difference is for an 8474 vs 8374 both IWG?

 

There are plenty of examples of divided but single EWGs being successful if done properly. Even the EFR IWG T4 is a divided single flapper. Because unless a dual WG setup has screamer pipes they merge at some point. Which highlights in itself that there’s more detail involved that broad strokes likely don’t account for.

Even though I often speak against a V-band, I’m of the yet to be proven opinion that if the manifold is divided right up to it, with both flow streams entering the turbine housing inlet at a close to parallel orientation, and necking down to it in neither too short or too long of a transition so that there’s a substantial velocity increase of the pulses as they enter, that it’ not going to be the same as the typical open scroll result.

A couple of factors to consider is that unlike a 4+ cylinder piston engine where pulse timing might not be equal, a 2 rotor engine has equal pulse spacing such that with equal length piping from the engine port to turbine inlet the pulses will be in synch with each other for a smooth transition to the turbine wheel. Another factor to consider with open vs twin scroll is A/R value.

There’s a test on the Garrett website where a team road racing a Honda 4-cyl dyno’d both a 0.83 open vs a 1.01 ts on a 3076 turbo. Despite being open, the 0.83 was more responsive and higher torque down low, with the 1.01 ts coming on and performing better up top. You can readily deduce that if they had a 0.92 open option the result against the 1.01 ts would be closer to each other. Which is why it’s often suggested, but possibly overlooked, to pick an open scroll A/R a step smaller than a twin scroll. Because in that situation, if they were both 1.01 open and ts, then the ts would likely be better low and the open coming on better up high.

There are many factors that can muddy the water on it. Which again highlights that there can be more to a result that was achieved than some people will want to be bothered with accounting for.
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