Shainiac

iTrader: (7)

That looks like a cross sectional drawing which will not necessarily display the widest section of each passage, but just a view of both at one specific depth. as if you cut it in half with a band saw.

ptrhahn

iTrader: (9)

He also sent me these—I've no idea what they mean.

Rx7aholic

iTrader: (22)

Men this must be very frustrating. I was so gun ho of the 8374 setup, I dump my suppose to be my new setup s363 and start buying parts for this turbo like the mnaifold, after reading this post i am at a standby right now and not sure if i should hold out or continued buying the parts to finished my setup.

blue87

iTrader: (2)

Sounds like BW is being pretty helpful did you ask if they would swap out a housing for you?

WANKfactor

iTrader: (1)

If you can remove the divider you can port it. If you dont trust yourself with a die grinder take it to someone who is good at porting.
Edit: or as above see if BW will swap you another housing.

Tuning4life

iTrader: (2)

Those are the boost levels you want to run (cannot see them in the shot) but he is showing you the calculated wastegate percentages and they should be under 40% for the boost level you want to run.

What is tough using that calculator is guestimating what the VE percentage is and what size engine to use for our rotaries.

He is showing you that you want to run an 80MM turbine wheel.

The A/R of the turbine is less important than the wheel size. I would go with a smaller A/R and a larger turbine wheel if you want spool and flow.

It is unfortunate that you cannot control the boost like you want with the 8374 IWG. It seems as though you are in the minority, with only a few people having issues controlling boost.

The rep is saying to run a larger turbine wheel because it flows more volume, and the engine flows a certain volume, hence less needs to be wastegated.

ptrhahn

iTrader: (9)

Interesting question I've been discussing with Brian @ Borg Warner.

I've not heard of anyone having trouble controlling boost with the 7670, but are there people having trouble? Based on the dynamic we've been discussing whereby the 9180 should be MORE controllable due to the 80mm exhaust wheel flowing more, the 7670 should have RAMPANT control issues with the 70mm wheel.

They are all the same exhaust housing casting, just with a different contour for the wheel.

Tuning4life

iTrader: (2)

Excellent observation. So you have the volume of the engine and how much volume of flow it can move. the secondary part is how much can the turbo flow through the volume of the engine and at what efficiency range right?

so perhaps the 8374 is much more efficient and is the sweet spot for this engine, hence it can flow a lot more volume and at a much cooler temp making a lot more power/flow, when you try dialing down a lot more flow you need more wastegate to hold say a 10PSI value.

With the 7670 you aren't flowing as much volume of air (compressor is smaller) and isn't in its sweet spot for efficiency, hence you don't need as much wastegate.

so you either "choke" the flow going into the engine, or your let it all flow out the wheel at the back of the engine (9180). Keep in mind that a 9180 isn't in its peak efficiency range till the upper rpms, not like the 8374 which basically travels up peak efficiency when ramping into boost.

it seems as though the efr 8374 doesn't choke it on the compressor side, but flows enough to not choke the engine on the turbine side needing a lot of wastegate which is just a hair too small leading to boost creep.

There might also be other factors with your engine that lead to worsening the issue. We do have a lot of people running these turbos at sea level who can maintain a pretty low boost pressure with these IWG.

Obviously I don't know the exact root cause but this is all speculation.

Tuning4life

iTrader: (2)

Let's look at what we could do to reduce PSI

Here might be some solutions.

1) increase wastegate size.
2) decrease flow into engine.
3) decrease velocity of flow into turbo.

Basically change the VE of the engine.

Run a small air filter, decrease exhaust piping after turbo, run larger manifold runners, whatever else people can think of. perhaps run a smaller intercooler with large pressure drop across it.

BLUE TII

iTrader: (9)

ptrhahn


Interesting question I've been discussing with Brian @ Borg Warner.

I've not heard of anyone having trouble controlling boost with the 7670, but are there people having trouble? Based on the dynamic we've been discussing whereby the 9180 should be MORE controllable due to the 80mm exhaust wheel flowing more, the 7670 should have RAMPANT control issues with the 70mm wheel.

They are all the same exhaust housing casting, just with a different contour for the wheel.

The 7670 has a couple factors working for it that help prevent boost creep on the rotary.

On the top end the little compressor just flat runs out of flow on a rotary. Most it can pump out is 18-22psi on a street port. If you crank the boost up above that for low end torque as I did it is dropping by 5,000rpm anyways.

Additionally the small exhaust wheel increases EMP killing the engine VE. Less power = less exhaust

-----

The 8374 has a larger compressor, so obviously can flow more air and therefore creep easier on the top end.

The larger exhaust wheel on a rotary just means less EMP and more engine VE for more power = more exhaust.

Does Brian understand we are operating the 8374 in surge on a rotary? Most engines struggle to spool a turbo that size.

BLUE TII

iTrader: (9)

^^^ Tuning4life has go it.

You are likely struggling with boost creep where others aren't because your 8374 engine system does not have some restrictions that others have. Could be anything from intake filter to exhaust tip.

Simply add that restriction in (I would choose a 1.5" exhaust tip for the track or a high flow cat for a street car)

or go with dual 44mm wastegates.

or put the stock twins back on as your restriction.

or do a hybrid systems of your IWG system with an external WG manifold you will still have a nice quiet street car when driving normally and when you really really get on it or are at the track the external WG will open for great top end VE at the low boost you want.




----

Like I said before, I struggled with this boost creep problem using a 60-1 compressor and "P" trim exhaust wheel in the stock S5 1.00AR exhaust housing with its dual internal wastegates. Well, it started with "O" trim exhaust wheel and then went to clipped "P" trim which didn't help boost creep much.

This turbo set-up is very much like the EFR IWG and Turblown cast manifold.

I ported the wastegates, open vented them with their own downpipe, removed the flapper and ported out the holes and used a 60mm external WG.

Everything I did to improve WG flow also improved overal engine VE so the boost creep persisted (though it shifted from a midrange boost spike to top end terminal creep).

Finally I ported the turbo housing scrolls twice their initial width (divergent turbo housing AR) and ported the manifold runners and turbo housing runners huge up to the now huge wastegate passages (larger than turbo passages) with flow favoring the wastegates.

Had a tiny bit of very top end boost creep after this which I solved with lowering the WG spring to below the boost I wanted to run so the WG fully opened at low boost and used a MBC to bring boost back up.

Finally fixed the boost creep, but ofc the turbo spooled lazier in the low rpm from the larger exhaust runners.

I should have just kept the exhaust restriction because then the turbo had low end punch it just impeded flow on the top end exhaust flow enough to stop boost creep.

"Fixing" the boost creep killed low end power and did very little for top end power (small gain from increased engine VE at same boost).

ptrhahn

iTrader: (9)

Hmm. This all seems a little counterintuitive.

OK, well, if you opened up your wastegate and it made the creep the same, worse, or shifted it higher in the rpm range, could it be that the gate is opening too soon? I'd certainly rather see a little spike in the mid range.

Two points:

1. Dan Chadwick runs this turbo on a longer-runner manifold, and uses the HIGH BOOST canister to run 12 psi (he says the lower ones drop off). Here's what he sent me:

"Hi Peter, sorry for the delay, don't get on facebook much anymore. The lowest we get with the high boost spring is 13psi, Rock steady with no creep. We tried the medium spring but boost would fall off at about 12 psi."

2. Jacob Cartmill noticed a phenomenon whereby the medium canister actually controlled boost up top better than the low. This was in part where the directive to run the medium canister came.

Do I somehow need to have the wastegate crack later to limit VE?

I'm also thinking that "a little" restriction elsewhere isn't going to do the trick. I've been down that road with the twins.

Turblown

iTrader: (12)

Peter,

Do you want to just send me your IWG housing and I will get the WG divider removed? I think this will solve your issue and I would like to make this option available to the 2% of people who have creep issues( assuming it fixes it). To be clear this will be free of charge excluding inbound freight to us and done via mill.

BLUE TII

iTrader: (9)

Hmm. This all seems a little counterintuitive.

OK, well, if you opened up your wastegate and it made the creep the same, worse, or shifted it higher in the rpm range, could it be that the gate is opening too soon? I'd certainly rather see a little spike in the mid range.

The creep did shift to higher and higher rpm.

It should be noted that by the time I "fixed" the boost creep the system VE was so high that later when I went to raise the boost and max out the turbo the 60-1 could only muster 18psi. 340rwhp on 10psi, 380rwhp on 14psi and 385rwhp on 18psi.

Before all the WG work it was boost creeping over 20psi by 3,000rpm.


Do I somehow need to have the wastegate crack later to limit VE?

You have something there. It could be the wastegate closing some in the higher rpms with the stiffer actuator spring that is lowering their engine VE and keeping it from boost creeping.

At one point I ran my 60-1 with no wastegate what so ever. I would boost in the low rpm, but then it couldn't maintain boost in the high rpm.

I also found the same thing on my 7670. In initial tuning the WG line fell off and boost shot up to ~30psi in the low rpm, but then boost plummeted just as rapidly.

Normal turbo behavior if you look way back into the early days of turbo charging with "free floating" wastegate-less systems. Turbo and cam sizing was critical.

BLUE TII

iTrader: (9)

If you wanted to test this theory you would wire your WG flapper partially open to see if it still had boost creep.

Midrange boost might be too high from my experience, so get on the gas from high rpm only.

It goes without saying testing like this should be done on race gas.

ptrhahn

iTrader: (9)

If I understand the dynamics correctly on the actuator, if the VE theory was correct, ADDING pre-load to the canister should do the trick—it would crack later, and open less far. I assumed all canisters opened to the same place, regardless of the spring pressure, with only pre-load affecting the end-distance, but maybe that's not the case?

The only data point I have was that going from 3.5 turns to zero turns on the medium canister seemed to lower the boost about 2 psi, and switching to the low boost canister on zero turns had no affect, but that wasn't a highly controlled test (different times/temperatures). I could crank on a few turns and see what happens, and or try the stiffer spring (high) canister.

ALSO: to be clear about what Blue TII posted about the 8374 operating "in surge"... are we talking about compressor surge or turbine surge (the latter I've never heard of). If it's turbine, at what rpm roughly would this begin to happen?

Elliot, that is a gracious offer—I'm not in possession of the car at the moment, it's at IRP having the clutch fixed. I'll give you a call on it.

Mazderati

iTrader: (3)

No idea whether porting would fix the issue, but extrude honing may work if the passageways are too tight for die grinding.

Turblown

iTrader: (12)

WG divider and T4 divider removed up to the WG. This has increased the surface area, and direction of flow considerably. Very curious to see how this works out for Peter.

Rx7aholic

iTrader: (22)

Do anyone know how setup an electronic boost controller on this type of setup? Do u have to use the solenoid that came with the turbo or u can bypassed it?

Turblown

iTrader: (12)

Electric Boost Controller Solenoid configuration diagrams for Mac Valve & BW EFR

arghx

iTrader: (3)

Hey I am just catching up with this thread.

My main comment on the above quoted part of your thread is that the turbo engineers at the suppliers like the one you spoke to are used to dealing with engine dynos and turbo gas stands. I could go into detail about what those two attachments actually mean, but that's not going to do you any good. The calculations they make require a lot of information that you just cannot supply to them with actual measured data, just guessing and heuristics (rule of thumb). There are a lot of correction factors involved as well.

I've dealt with this in my day job. When we are evaluating which turbo to go with, we have to make a separate Excel spreadsheet for each supplier. The Excel file has a ton of calculations, and while many of them are common the calculations are still bit different for each supplier, as each uses a bit different correction factors and assumptions.

The turbine map he sent you and that app/calculator he is using is mostly useless for you--not because the principles aren't sound though. You just don't have a lab in your garage.

Rx7aholic

iTrader: (22)

Actually i was hoping someone have a greddy profec b configuration setup and not using the bw black soleniod valve. The Mac valve looks confusing.

eage8

iTrader: (9)

you just replace the BW solenoid with the greddy solenoid... there is nothing special about the BW unit.

http://www.greddy.com/upload/file/PRofec_Bspec2.pdf

Rx7aholic

iTrader: (22)

Hey guys anyone with this kit is exprience exhaust leak by the downpipe v-band or manifold?

eage8

iTrader: (9)

v-bands get warped when welding very easily. you can get gaskets for them. I've gotten a few to help with my v-band leaks. (I don't have the turblown downpipe)

Cometic 3 Inch Vband Gasket