As suspected this turbo responds incredibly fast for its size. This is our shop FC3S with the following specs to take into consideration for boost response;

FMIC with 2.5" tubing
Our long runner FC3S IWG turbo manifold
Pump Gas
Large Street ported S4 Block( 8.5:1 rotors)
4inch downpipe/midpipe and 3" Apexi N1 catback

It makes 16psi by 3100rpms without a lot of time spent tuning response( will be done on the dyno).
Now yes this is not as fast as our 8374 IWG kit( 62mm inducer/74mm turbine- vs the 9180s 68mm compressor and 80mm turbine). We achieved 15 psi by 2500rpms on that 8374 FD IWG turbo system. However that was with a Vmount, E85, shorty manifold, stock ports and 9.0:1 FD rotors( all which help with boost response).

Most T66 or To4R cars usually see 15 psi by 4500rpms on this same combo( We just did one last year).

BorgWarner EFR IWG FC3S Turbo System

Borg Warner EFR 9180 Turbocharger

 

Sounds too good to be true! T04S/GT35R spool with T04Z power potential.

EFR 9180 with semi p-port could put FD back on time attack map without the $$,$$$ transmission needed for a "peaky" powerband.

So, that is your usual "smaller than industry standard" exhaust manifold runner diamter to help achieve that phenomenal spool?

It will be interesting to see if the smaller diameter runners impact peak power in any appreciable way on this larger turbo system (I'm thinking not).

 

T3 GT35R/To4E spool with GT4294R power ! This should should make 630-650rwhp in this combo with a 4" exhaust I would think. T4 1.45 EWG maybe 700+Rwhp..

We are going to add E85 and hit the dyno as soon as we finish pumping out a bunch of EFR turbo kits.

We are also installing the same turbo on a few FD Shorty kits..

 

I'd be interested in seeing this on the shorty FD. Might even convince me to swap to it with the .92 IWG version to get rid of my annoying open dump and BOV noises.

 

Anyone know the spool up difference between the T3 .83 A/R and a T4 divided .92 A/R?

I have the option to get the T3 .83 A/R for a really low price, but if the performance difference is huge I wouldn't, if its marginal, perhaps I would go for it. its a really big price difference though.

 

Great results! When can we expect to see higher boost pressure results?

Does the 9180 feel GT35rish on the street?

A .83 T3 is absolutely teeny tiny. It is similar to a .64 T4 in terms of flow which is ridiculous for a rotary.

 

I am hoping to jump on dyno next week. We start the flex fuel e85 tune tonight. Response is phenomenal and very comparable to a gt35r. It actually pulls pretty good at 8 psi ! I intend to run this up past 20 psi( but not too high, this is just a street car with 265s).

 

look forward to seeing the results mate.

 

I don't claim to be an expert but I can read charts and graphs and follow the logic of debates.

One thing I noticed (hence the logic thing) is that turbine housings are not viewed as one component, they are viewed along with the system, the system being the size of the turbine wheel that the housing is paired with. We have a large efficient 80MM turbine wheel and we don't need a large A/R housing tied to it. in fact, we can go smaller with turbine A/R as the wheel size gets larger.


Look at the matchbot that BW provides us. It shows on its plot that a 80MM wheel and .83 T3 A/R flows more than a T4 1.45 A/R 74MM wheel. That is a TON of flow.


I then researched about the difference between a divided and undivided manifold in terms of spool. Some people are split on it but most favor divided housings because of quicker spool and response. BW wrote in the EFR technical broschure that divided housings are perferred for spool. that a .91 A/R divided T4 will outspool a single scroll .83 housing but have the same flow up top roughly. remember that a divided housing is divided and the divide takes up room. a single scroll is a large opening.

Then I got to thinking that they are talking about piston engines and with a lot more "pulses" typically 4 separate pules per turbo and piston engines have a lot of "exhaust downtime". A rotary is different, our single scroll is their divided. We have two large ports that produce a lot more heat and exhaust. We also have a continuous stream of exhaust from each rotor going all the time. I am unsure the effect of this when it comes to single scroll vrs. divided. I was wondering if anyone had any experiences.

I recently tuned a single scroll T3 garrett (I think) 60-1 turbo with a .82 turbine housing (journal bearing). It's a 60lbs turbo for air flow and I guess it could have a stage 3 or 5 turbine wheel on it so I am unsure what the turbine wheel size is. When I tuned his car I honestly didn't feel any choke points and the spool up is pretty damn good. I think its better than my .84 A/R P-trim wheel (74MM) ball bearing 62MM compressor wheel T4 divided housing. I think mine makes more top end power but I wouldn't say these two turbo's are worlds apart. I want better spool, IWG and no BOV stupid chirping sounds.

so I then went to comprable sized turbo's with single scroll to divided to see if I can see spool up differences but its tough to compare when everyones set ups are different. so I didn't want to get too involved with the research in this department. What I did see wasn't mind boggling, atleast on a dyno chart. I know dyno's also read differently.

I am trying to figure out what the differences are between a single scroll T3 .83 housing with BB vrs. a larger T4 .91ish divided housing. If the difference is basically moot on a rotary, I might try a T3 single scroll 9180 or 8374 turbo for a wicked low price.

 

I'm not sure there is much to debate. Look at what Mazda spent developing the twin scroll system on the S4, and then just abandoning it for the superior divided housing on the S5. Would they really have gone to all that cost and complexity on the S4 if the same results could have been achieved by playing with A/R?

 

I guess my situation is my GT3574R .84 A/R divided housing T4 spools 15PSI by 4,200-4,500rpm at 6,300 feet above sea level. Yea, the air up here is thin. I do a lot of canyon road drives and I like using 3500-7000 rpms, its nice shifting that powerband down as far as I can to get a wide powerband. What would a T3 single scroll 9180 or 8374 do compared to what I have. and is the $600-800 difference in price worth the spool difference (I get what I want, IWG, BOV recirc). They have superlight weight turbine wheels on these turbo's which helps spool, the difference being greater as the turbine wheel gets larger. If I can get 15PSI out of an EFR9180 at 3500 RPM, I would do it. or if it would be a better bet to do a EFR8374 and I could get 15PSI by 3500 I might do that. Right not I am getting around 5-6PSI (2-3PSI sea level) around 3,100RPM. I run my car at 7,000-8,000FT above sea level a lot and these big inconel turbine wheels get killed spool wise with a lot lower flow at lower rpms.

If the EFR8374 gets 15PSI by 2500rpms, I would be fine hitting that at 3500 rpms. I get 15PSI right now at 4,200rpms or so. I have done everything in my power to increase spool with smaller V-mount intercooler, longer intake, velocity stack, large intake filter, etc. All this would be used with an EFR turbo. I am sure this turbo would be insane at sea level though.

 

lOOkatme
Quote:
Originally Posted by Flyweight View Post
Great results! When can we expect to see higher boost pressure results?

Does the 9180 feel GT35rish on the street?

A .83 T3 is absolutely teeny tiny. It is similar to a .64 T4 in terms of flow which is ridiculous for a rotary.
I don't claim to be an expert but I can read charts and graphs and follow the logic of debates.

One thing I noticed (hence the logic thing) is that turbine housings are not viewed as one component, they are viewed along with the system, the system being the size of the turbine wheel that the housing is paired with. We have a large efficient 80MM turbine wheel and we don't need a large A/R housing tied to it. in fact, we can go smaller with turbine A/R as the wheel size gets larger.


My direct experience with T04B stock hybrid and "P" trim exhaust wheel in the tiny (T25?) stock S5 TII exhaust housing has given me some unique insight on this.

You can't really think of turbo exhaust housings as tiny or large based only on turbo frame inlet flange (T25, T3, T4, T6) or A/R alone. "Size" can become a misnomer.

First let us look at volume flow as the choke point-
If you are putting the 90mm exhaust wheel in a 1.00 AR T3 and a 1.00 AR T4 exhaust housing you are going to end up with the same or larger scroll slot aperture on the smaller T3 exhaust housing when you bore it out for the larger wheel.

So, the the scroll slot aperture is obviously not the choke point with the same size exhaust wheel on the smaller housing.

So, what about the remainder of the exhaust housing? Well they are both 1.00 AR and so have the same exact volume to radius ratio from scroll slot up to the smaller housings flange mating surface.

The only difference on the T4 housing is it has more volume at the flange mating surface.

Now start looking at actual turbo housings. Interestingly, most the modern T4 housings I have seen have a quick reduction of volume before the actual constant volume to radius section of the actual exhaust housing AR. Its a little velocity stack into the actual constant AR runner at the flange.

Once the T3 exhaust housing is put on the manifold it is much more a question of manifold collector design on whether there will be any volume flow potential difference between the "larger" T4 flange 1.00AR turbo housing and the "smaller" T3 flange 1.00AR turbo housing with the same exaust wheel.

You could easily design that same "velocity stack" transition from the T4 flange to start of constant AR into the collector of the manifold before the T3 flange.

You are in effect only moving the flange closer to the turbo- the restriction is not the turbo flange, the flange could just as easily be another 3" toward the exhaust wheel and T2 sized with a good collector in front of it.

Where does the "restriction" of smaller volume manifold runners/turbo flanges relative to the same AR and exhaust wheel begin?

Very hard to say as Turblown has shown great success with their "smaller than industry standard" exhaust manifold runner diameters.

_____________

Wastegate entry is another "choke point" factor-

The more convoluted the entry to the wastegate the worse the natural exhaust flow is into the wastegate. This creates a feedback loop where the exhaust manifold pressure increases greatly as the engine exhaust stroke has to push the exhaust out either the convoluted WG entry or through the turbo exhaust housing. Each one becoming more of a restriction as exhaust volume increases with engine RPM.

______________


Exhaust housing AR as choke point-

The "smaller" the AR (I like to say "tighter") the higher the exhaust velocity is as it strikes the exhaust wheel per given engine rpm/exhaust volume because it is hitting the wheel at a lower angle of incidence. The problem is as exhaust volume builds the exhaust velocity striking the wheel also builds and will reach a point to where any further velocity increase is a large restriction to flow- it chokes flow.

You can't design a manifold/collector to change this "smaller" AR choke, it will happen at whatever rpm the exhaust volume creates the choke point no matter what is ahead of the exhaust wheel.

T3, T4, T6 0.63 AR on a rotary will all choke at the same RPM and drop torque with the difference being the larger flange turbos will also have worse low end power from pumping losses due to manifold collector volume at lower RPM. It is essentially like the difference between a log manifold and a true divided manifold in terms of of what the engine and turbo exhaust wheel sees.

As you raise the AR ratio the manifold/collector/flange volume may become the restriction.

A 1.45 AR T6 will definitely out flow a 1.45 AR T25 if the T25 exhaust housing has smaller manifold runners/collector/lead in to turbo flange that becomes the "choke point".

This is for a traditional radial flow exhaust housing turbo. Interesting things happen when you change up the exhaust entry to the exhaust wheel with mixed radial and axial flow as I found with my too deeply bored stock hybrid and EFR has found with the Indy Car 7163 mixed flow turbo.
______________


Considering the above factors, it is easy to see a "larger" AR T3 flange turbo exhaust housing with the same size exhaust wheel could very easily flow more exhaust volume at high engine RPM than a "smaller" AR T4 flange turbo housing through manifold design.

 

scathcart

I'm not sure there is much to debate. Look at what Mazda spent developing the twin scroll system on the S4, and then just abandoning it for the superior divided housing on the S5. Would they really have gone to all that cost and complexity on the S4 if the same results could have been achieved by playing with A/R?

This statement seems to misunderstand the fundamental reasons they created the S5 true divided exhaust housing/turbo.

The S4 dual AR switching turbo was mounted on a log manifold and they found that the pulse interference between rotors created more pumping losses than could be compensated with tighter primary AR and larger secondary AR.

S4 turbo exhaust housing is crazy difference, something like 0.4 primary and 1.4 2ndary from memory, but I will check the Yamaguchi book.

But basically, they weren't going to overcome the pumping losses by decreasing the primary AR or increasing the 2ndary AR without dropping the switching point to just over idle. Might as well put an (even) heavier flywheel than the 27LB S4 one if off idle "torque" when clutching is their only objective.

If Mazda had used a dual AR switching manifold AND true dual divided manifold/turbo the results (and complexity) would have been much greater from a reduction of the log manifold pumping losses. This is pretty much what the 3rd gen sequential system manages and you could adapt the sequential turbo manifold to a true divided dual AR dual scroll turbo for this variable AR switching manifold.

 

Do you think there's any value in the increased "heat capacity" of the 9180 for street applications in terms of longevity and reliability? Those glowing downpipes look so scary.

 

I tried to complete the street tune very late last night, but ran into a fuel pressure issue. To be clear I always prefer to dyno tune, but its always nice to see if there are any kinks before hitting the dyno.

Anyhow that is now fixed, and I have had more seat time personally( I have not been driving it).

There is definitely more lag in 1-3rd than 8374 IWG FD system. Enough for me to say I would stick with the 8374 for a street car. The 9180 does not give you that 20B feel( intense low/midrange pull), albeit I am sure the 9180 will give a lot more punch past 6500RPM( which is more of a drag/freeway car).

Keep in mind that the 8374 @ 30psi will never hook on the street, Shawn here can't hook with his 315s. You really need boost by gear for an 8374.

I have a lot of cars to tune next week, so I am hoping to get this car very soon and do pump vs E85 around 15psi, and then 20+ on E85 only.

 

i like what im seeing. Going to keep following this post, as i plan to buy one of your turbo kits soon.

 

Interesting!

Is there a graph of this @30psi some place?

Do you plan on taking it 30psi+?

 

Any dyno graphs?

 

I am having an issue with the secondaries so they are out getting cleaned in additon to a 10 micron fuel filter. I have been on the dyno a lot, just not with this car yet..next week !

 

It hold 12.5 psi to 7200rpms with controller off. E60 through 4th gear. 4 inch dp/midpipe and 3 inch catback. Long runner FC manifold. Tuned to 17 psi now with controller on. Dyno friday. I am going to stick with an e85 blend, as this is a s4 block with oem apex seals. I will run it as high as the injectors or pump will go. She pulls very strong ! Surges below 3200rpms if boost is higher than 12 psi. 8374 does similar...

 

Dyno is done. Waiting on videos. Pulls clean to 8000rpms with no torque or hp drop off. Ran out of injector at 17psi. Waiting for ID1700s x 4 and adding an aftermarket Industries Sp800 with a second staged walbro 450.

 

Sounds awesome dude....cant wait to see the vids and dynk graphs. ...need to decide between a 8374 and 9180

 

Still waiting on the video.. So while we wait;

Ran out of fuel pump( walbro 460LPH E85 version). E65 blend. It will actually make 17psi by around 3000rpms, but it will go into compressor surge, so I have backed the controller down around 2500-3500rpms. Nice flat torque curve, drives really nice.
This turbo should really come alive around 25psi. We are adding an aftermarket industries SP800 with twin walbro 460s( 2nd pump will be staged at 3 psi by the ECU). Also looking to add 4 ID1700s as soon as they are released. Then I will dyno at 25-30 psi. We are going to move this car down to an 8374 however, as I don't intend to run more than 25psi on the street. This 9180 is moving over to our FD roadcourse car, and being pushed to 35-40 psi

We are also going to add a turbosmart IWG actuator with base spring pressure 15psi, and see if that helps at all with keeping the boost curve a little flatter.

 

^ I've been on this forum for 13+ years and it's a bought time someone posted a full rpm range dyno chart.

 

200lb/ft @ 3000rpm is mighty impressive for a turbo that size

With the EFR range you kinda have to, afterall they actually do something meaningful below 4000rpm