shlammed

iTrader: (8)

subaru stuff does not correlate well when compared to normal i4 engines.
that and the boost control isn't well setup there to compare with the TS making less boost everywhere after 3500rpm.

looking at that, I would say that if the boost levels were identical, the t4 Ts held power longer into the limiter. the number discrepancy is because of the boost differences among other things im sure. in the upper rpm's there is a difference of up to 5psi... that's pretty big.

psyber_0ptix

iTrader: (4)

Whoa that's interesting. And that's a t25 0.85A/R against the 0.80A/R t4?

18psi

iTrader: (76)

Let's see a plot of what you're talking about then?
Cause actual results data beats theory urry single time.

psyber_0ptix

iTrader: (4)

I'm in for results. I still want to see results of a SS 7163 on a miata but even that seems to be lacking. This is all for science. I agree, real data and facts always beats conjecture. But no one wants to step up to the plate and share or prove the failure because of financial investment. At least for me, it's a manifold, downpipe and exhaust housing. Then convert back to the trusty rusty artech if it sucks.

shlammed

iTrader: (8)

I don't think that the comparison is necessarily bad for the turbo if you read into the details, but you quoted some power numbers suggesting that its loosing power because of the twin scroll.
differences in power are from different boost levels. tuned to the same boost level, your gaining both low and high end power in that comparison.

18psi

iTrader: (76)

You realize that both of those curves were pushed to their maximum power output right? meaning the reason it's dropping boost is cause it's choking up at the hotside. You can see that they both make the same boost in the midrange. I'm asking for plots cause I'm happy to be proven wrong, but so far you haven't proven me wrong at all and you have just theory with no actual testing results/data. I've seen this on other setups too, not just EFR. I also thoroughly experimented with exhaust back pressure on my current sti, and can tell you that even on the same turbo once it starts choking at the hotside, power drops and boost drops even at 100% BCS DC and there's nothing you can do about it.

If my findings are incorrect, let's see the data.

psyber_0ptix

iTrader: (4)

Let's set up a gofundme for miataturbo science!

shlammed

iTrader: (8)

yeah, lets get it going.
I will chip $20.


18, I know what your saying about it being choked... its a thing... having both turbos in hand, you would have a hard time telling me that the t4 would flow less than the t25. the only way i could see it loosing top end vs open scroll is the way it interacts with the turbine wheel itself and not because of the mass flow area.

Back to the welding table I go. I just finished a t4 TS top mount manifold for a 1.8 with 6258. i don't know that we will see it pushed to the absolute limits like psyber is doing, but i would love to hear that it is.

psyber_0ptix

iTrader: (4)

I feel like I've reached my glass ceiling for my build. I can't even comfortably take logs. When things are rebuilt, and buttoned up and broken in, I swear I'll fly Vlad out over a long weekend and rent a dyno lol

shlammed

iTrader: (8)

would it be too much to ask for you to try and log manifold backpressure...like we have been chatting about on FB

Both on your existing and future manifold

psyber_0ptix

iTrader: (4)

What pressure transducer would I use? I have an EGT port I can sacrifice, but have no other bungs on the manifold. It's swaintech coated so I don't know how easy it'll be to weld another on

shlammed

iTrader: (8)

is the EGT in the manifold? specifically the collector would be best and yeah, that will work fine. if its in one runner, that's not ideal because it will show more pulsing but will still work.

basically you want a few feet of copper tube, to reduce the heat to the transducer and then you run a pressure sensor with 2bar more than your boost pressure. It can be a psig type sensor since we are only working in positive pressure in the manifold. The AEM exhaust pressure kit uses their normal 100psig pressure transducer.


I will toss a pair of bungs onto the manifold to use for EGT/emap

matrussell122

iTrader: (1)

I think my manifold will have 2 egt bungs i dont remember. But for science we can put extra bungs for a pressure transducer if you guys want numbers.

Also at work we use only gems pressure transducers and they seem to work good.

psyber_0ptix

iTrader: (4)

Sadly mine is in runner 3. Matrussell, you are our only hope.

shlammed

iTrader: (8)

the pressure does equalize... but you need to smooth it quite heavily the further you get away from the collector. sometimes to the point that you need a physical canister to dampen the pulses.

18psi

iTrader: (76)

I was going to say: when the time comes we can probably throw together a dyno tuning weekend and dial in your car as well as others in your area. whole lot less expensive when you have a group that's exactly what I'm getting at. the inlet flange is just that: the inlet flange. restriction is usually not at the inlet flange, which is why (on most other cars aside from bp) up-sizing the hotside while retaining identical inlet still nets a good chunk of top end power.

ryansmoneypit

iTrader: (6)

I would be game for a mass dyno tune. Ive got my own street tune pretty good, but dont have anyone local I would trust to work on it any further. I have a real problem with handing my tune over to random people who claim T00Ner

psyber_0ptix

iTrader: (4)

@Shibby and I have discussed this before and he scouted a place out that rents the dyno out. IIRC MachV also rents theirs out; we'll just have to see what works for where people are located. We can just get it hobbling along via remote tune, set a date that works for everyone buy a first class ticket for Vlad, and go ham.

I'm no vender so not sure about how to set this up and gather interest. Whatever works for Vlad Re: family/work schedule. I'm flexible aside trying to hit MATG2019

Shibby

iTrader: (4)

I'll check with the shop on logistics. The dyno is in Hagerstown, MD. I could house a couple of you non-local guys for a weekend.

I'd bet my place is cheaper than Mach v and probably has way more availability.

Dyno & Tune Reservations ? Hub City Performance

shlammed

iTrader: (8)

understood.

The t4 has a larger a/r as well.. so I still think it would flow at least just as well...
especially so on an engine that is 25% smaller than the one being compared.