ptrhahn

iTrader: (9)

I'm pretty set towards the v-band hotside—the biggest issues I see with single turbos on track are cracked or warped flanges, and broken wastegate diaphrams. My theory is, flanges warp because they are oblong and heat/cool unevenly, and have uneven pressure on them... v-bands are perfectly round and evenly clamped.

BLUE TII

iTrader: (9)

Treadstone is making stainless v-band exhaust housings for the EFR turbos.

They have a 0.86AR "T3" v-band housing for the EFR 7670 currently and I bet they will expand to the larger turbos soon.

Don't get too hung up on the T3 vs T4. The AR and exhaust wheel size is more important for exhaust backpressure/thermal management.

A v-band open volute T3 exhaust housing will flow as much or more than a divided T4, its really the manifold design backing up the turbo housing that is going to make the difference.

I can tell you that the EFR T4 divided exhaust housing necks down fast after the flange as does a "T4" GT35R.

Because of the larger EFR exhaust wheel I would take the 7670 T3 V-band option over the smaller exhaust wheel of the GT35R for the track/thermal management.

Now, if when you say GT35 variant you are also talking about some "GT35R" hybrid with a larger exhaust wheel- then you would just be losing out to the better spool of the EFR, but it would be the same or better from backpressure/thermal management perspective if you used the Tial 1.03AR housing.


Well, you can always save yourself some $$ and use the inelegant solution of welding the stainless EFR T4 divided exhaust housing directly to the stainless manifold...

ptrhahn

iTrader: (9)

^^^^^

Well that is interesting—I assume those Treadstone housings don't work with IWG, so is there an otherwise identical EWG version of the 8374?

Or maybe more importantly, are the flanges on those housings the same as those on the TiAL housings? If so, I could go w/ the 35R now, and then switch if and when the 8374 variant appears. I'm likely going to be doing a fairly special manifold—not something I'd want to have to redo. Refitting a downpipe is less of a big deal.

I'd be open to a 35R "varient", so long as I can use a TiAL housing.

ptrhahn

iTrader: (9)

FWIW,
I called treadstone and they DO make a stainless v-band-in hotside for the BW 8674, but .84 AR, not the .92. The flange likely COULD be made to fit, but it's not exactly the same as the male/female TiAL 35R flange.

BLUE TII

iTrader: (9)

Well, it would be pretty easy to cut the v-band flange off the 35R manifold and weld on a v-band flange that matches the EFR.

The harder part is the oil and water lines are different, the downpipe location will be slightly different, the compressor cover is more forward on the EFR so charge pipes are a little different and also the longer chra on the EFR means it doesn't fit in the same area of the engine bay as the GT35R which has a really short chra.

I would not get the GT35R kit thinking to switch to EFR turbo in the future, I would decide on the turbo I wanted and fab/have someone fab the kit to fit it in the FD.

so is there an otherwise identical EWG version of the 8374?

Yes, EFR offers internal and external wastegate exhaust housings for the EFR turbos. I chose EWG housing for my 7670 as I knew the IWG would creep on a rotary. Its divided 1.05AR T4 though.

I am sure Turbo Source could make you one of their 8374 external wastegate kits using the 0.86AR Treadstone V-band housing.

The Treadstone 0.86 EFR V-band housing is really close in AR to the 0.92AR T4 IWG housing Turbo Source normally uses so I would expect spool and top end performance to actually be very close.
Especially considering the tradeoffs of smaller AR open volute versus the larger AR divided with less "swallowing capacity" (flow potential in turbo speak).

The Turbo Source long runner exhaust manifold design is exactly what you want on an open volute turbo on a rotary.

A short runner "log style" manifold with an open volute turbo would be a disaster on a road course rotary as you get way to much exhaust port communication between the front and rear rotor housings and resultant heat influx through the exhaust ports after the blowdown phase.

Craze8

Coming from the honda line of road course and boost, I agree with the above statement. While the log/cast manifolds are easy and cheap to come by, they retain heat and have backpressure issues. Ive had one and know of another to crack several times while road racing. While I have an fc and am doing research to go to a larger single for road course. I find myself hitting the same questions you are, which would work best. In for more/shared knowledge

Turblown

iTrader: (12)

This post is aimed at the original poster's question...

Recently one of our Adaptronic dealers, Unique Precision Rotary, pulled a GT35R kit off a customer's FD and installed our IWG 8374 kit.

The car made 355rwhp and 275rwtq @ 10psi on pump gas. This was also on a mustang dyno. Figure that is near 400rwhp on a dynojet. This was also with a raceported engine with no intake/exhaust restriction. There was ZERO boost control issues. I've also had two other customers report being able to hold 8 psi on stock port engines.

He said you cannot not even compare the two turbo kits in terms of response and power. He was amazed at both on the EFR kit.

IRPerformance

iTrader: (41)

Good stuff Elliot

ptrhahn

iTrader: (9)

Is the IWG a contributor to the response/power equation, or is that really a simplicity feature?

jacobcartmill

iTrader: (6)

the IWG is just a simplicity feature.

you can always "tune" wastegate response to keep them closed longer or whatever, but they are generally just closed until the turbo has already reached the boost you want, leaving them (mostly) out of the response equation.

BLUE TII

iTrader: (9)

IWG EFR housing is a slightly smaller AR, so that alone should contribute a little to response with a little drop in top end flow.

IWG 0.92AR

EWG 1.05AR

Besides that, its down to how well designed said EWG manifold is.

If the wastegate position and merge is compromised/poorly designed or a single wastegate is used the IWG could again have better response as BW spent time optimizing the IWG housings for motorsports applications.

silverTRD

iTrader: (36)

So lets say if I ran into the same situation Jacob did with his setup not holding low boost, Is it really an issue running on a track with a silencer or restrictor in my exhaust system? What else would I need, i.e. a separate tune? or...?

I ask because I too love the simplicity of the IWG and would like to track with it but not at 450+whp, my new motor is going to be a medium streetport so this is a concern for me.

BLUE TII

iTrader: (9)

Putting a restriction in the exhaust is a good way to get around boost creep on the street/auto-x.

If you seriously track your car with an exhaust restriction it is going to build up a lot more heat in the exhaust/engine compared to no restriction in the exhaust.

For the track it would be safer to restrict the intake by putting a small poor flowing air filter on it (even a stock FC airbox) or at minimum duct taping your cone filter until the creep subsides.

Problem with restricting the intake is it adversely affects spool more than a restriction at the very end of your exhaust.

I have more experience with boost creep than I would care to have

silverTRD

iTrader: (36)

Both of those situations seem less than ideal Of course. Can I just put a block of wood under the gas pedal? Lol!

Turblown

iTrader: (12)

The iwg version may play a role in reponse because we were able to make the manifold shorter. Side by side ewg vs iwg probably no difference. If one made a ewg manifold with wg runners that were not in the direction of flow( least amount or disturbence to main runner flow) then one might see a positive increase in response. This would be a high boost design only.

genzer

iTrader: (2)

Interesting...with which "kit"? There are a few different options lol.

lOOkatme

iTrader: (19)

IWG isn't just a simplicity feature but also a reliability feature. doesn't this remove one of your concerns in this thread about wastegates failing? Doesn't it eliminate the need for making cooling lines to the wastegate, and also reducing the chance of vacuum lines failing (wastegates are off the manifold and perhaps either line could hit the hot manifold somewhere). It seems like the vacuum line running to the diaphragm might be more robust.

the wastegate is also designed for the turbo, included with the turbo, from an OEM manufacturer. I see this as a win-win.

Also less chances of welds failing on the manifold since there are a lot less of them without the wastegate(s).

If you want the engine to be as robust as possible, make hard lines for vacuum and water/oil.

I think Fritz is a proponent of the stock twins because it exhibits all of the traits above. hardlines, internal wastegate, no welds to crack, etc, etc. This is what makes the system robust, yes it has its downfalls, but it also has a lot of upside because of the reliability of the system.

The only worry I have, and I am single, is that one of the aftermarket components could fail, mainly my FPR. Such an important component. My other concern is something failing to my wastegate.

ptrhahn

iTrader: (9)

Well, again, I think a v-band inlet set-up is pretty key, and I doubt those treadstone housings could be adapted to it, so between that and the fact that low boost (<15 psi) may not be possible, it seems like the IWG route is out.

So, the choices would be:

8374 EWG w/ .86 Treadstone v-band housing
GTX3582E w/ 1.03 TiAL v-band housing

I'm not quite following the affect of an open-volute vs. twin-scroll w/ regard to heat and spool time. Am I reading that twin scroll is better for spool, but open-volute is better for heat and decent for spool provided that the manifold is designed such that the flow from the exhaust ports from each rotor aren't pointed at each other too badly? So a shortly manifold to a TiAL housing may not be ideal?

Garret actually makes a divided v-band inlet housing as well.

BLUE TII

iTrader: (9)

but open-volute is better for heat and decent for spool provided that the manifold is designed such that the flow from the exhaust ports from each rotor aren't pointed at each other too badly? So a shortly manifold to a TiAL housing may not be ideal?

Yes, you have the idea. For maximum reliability on the track with an open volute exhaust housing you will want longer runners with a shallow merge angle.

Short runner definitely has its merits in spool whether divided or open volute- I am not knocking it- just saying it will impact engine longevity under torturous conditions.

I recently ran my little EFR 7670 on old HKS (medium long?) fully divided dual WG for short 3-5min sprints on a kart track and I couldn't believe the heat coming off the turbo exhaust side from running continuous 26psi!

ptrhahn

iTrader: (9)

The (original) plan was do an HKS-style v-band manifold (with good materials), GTX35R w/ TiAL 1.03 housing, and a single HKS 50mm or TiAL MVR 44mm (with MVSA-style additional heatsinks) wastegate.

I'm willing to trade a little optimum runner merge angle for better packaging with intake/IC (i.e. a shorter manifold), so long as it's not awful. It's going to be a helluva lot better than the twins.

The option then, would be to do it with an 8374 w/ the .86 Treadstone housing instead.

BLUE TII

iTrader: (9)

I would try either one of the set-ups you described... except the WG sizing worries me.

That HKS T04Z manifold pictured is set up for the 60mm wastegate and I believe medium to high boost for road course work/time attack.

I personally wouldn't go with a smaller hotside turbo and a smaller WG and expect to be able to run low boost.

I can tell you my twin MVR44 with WG priority runners are overkill (have run as low as 6psi boost without creep) on my 1.04AR, but I can't say by how much...

I know those 60mm WG are expensive and big, ran one on my last set-up.

ptrhahn

iTrader: (9)

My thought on wastegate size is, used to be all the standard 35R kits were single wastegate... something like Crispy's set-up, albiet not v-band, is a 1.06 T3 35R on a ported motor and a single Tial 46 (old style) gate, and I've not heard of any boost issues. If it will do 12 psi, I'll be happy, I don't need 6-7 psi. Dual gates would be a pain in the *** to plumb back in to the downpipe.

Triple-R: GT35R Single Turbo Conversion Install

One design difference I see on that manifold (old A-Spec) is a wastegate feed off of each runner.

ptrhahn

iTrader: (9)

^^
Crispy's setup above was able to run as low as 10 psi on track on spring pressure.

ptrhahn

iTrader: (9)

Well now this is interesting. I'd heard that BW wasn't going to do a v-band inlet, especially for IWG, but here is an example (albiet, looks like a smaller than 8374 turbo)... dated late 2013. Wonder what has happened with this?

Nerd?s Eye View: SEMA 2013 - Part II

It's hard to believe they would go through all of the trouble to clean-sheet-of-paper these turbos for racing, and then not offer a stainless housing w/ v-band inlet.

BLUE TII

iTrader: (9)

That is the EFR 7163 Indy Car turbo spec'ed for twin application.



All the Indy teams ran that except Honda was allowed to run a single EFR 9180 instead (also v-band inlet exhaust housing) in the 2012 and 2013 seasons, but Honda must now use the standard twins.