Is a BW 7670 too big for street application?

[stealthlead]

Hey guys, I've been going back and forth between turbos and single vs twinscroll for the better half of two years, so I would really appreciate some insight. Car is an 04 STi. I do understand I've probably overbuilt it at this point, and I do understand this will be expensive.

Basically I just want a fun street car that has a useable power band and good spool up. I'm not really interested in track or drag. I'm having the turbo kit custom fabricated and its being paired with an ETS 3.5" IC core. The turbo will be externally gated and rerouted back into the downpipe regardless of selection. The block is currently built but will eventually be replaced with a staged IAG CD and appropriately built heads. All other supporting mods will be accounted for as well but the point of this thread is for the turbo selection.

I'm currently debating between a Borg warner TS 7163, 7670 and considering a SS G series. The main reason I'm leaning towards the 7670 is having the option of an aluminum CHRA and basically having some room to grow in the future. The reason I'm considering the 7163 is to have more streetable power if the 7670 would be too large for this application.

Finally, the reason I'm considering a G series is because my tuner highly recommends it (although I do think they rep garrett), would make the piping simpler, and be slightly cheaper. However, considering this is basically a build from the ground up, I would think twinscroll would make the most sense here.

Would really appreciate some guidance and constructive criticism here.

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[subaru_gc8]

I think the problem between the 7163 and the 7064 is the turbine opening. they are different, the 7163 is a t25 and the 7670 is a t3 so you cant really swap between the 2 of them.
As for the g series, I saw a bunch of test on you tube that they did witht he g25 660, I looked like you get a good spooling turob but it seems to choke out even if you use the 92ar hotside. What I would use is the new g30 660.Im really thinking that that might be my next new turbo. another turbo yo might consider is the gtx 3067, it s pretty quick spooling turbo with a good amount of power on the top end.

[Murphy_WRX]

I can't speak to these specific turbos but if you want streetable power I would start by looking into where the turbo spooling starts. High boost that doesn't kick on until high into the RPM range of your motor won't be as effective for daily driving as something that starts at a lower RPM. It really depends on where you want your power band to be.

[stealthlead]

Originally Posted by Murphy_WRX

I can't speak to these specific turbos but if you want streetable power I would start by looking into where the turbo spooling starts. High boost that doesn't kick on until high into the RPM range of your motor won't be as effective for daily driving as something that starts at a lower RPM. It really depends on where you want your power band to be.

Lower/mid power, I would be willing to sacrifice a bit of top end. It seems like these borg Warner's like to spool up pretty early which is why they're the top contenders for me. I guess these g series are competing against TS pretty well though. I should have clarified that this is absolutely not a daily driver.

[subydude]

I***8217;d take a 7163 for something fun on the street. Low 400***8217;s on pump gas and higher 400***8217;s on E85. The 7670 wouldn***8217;t hit full boost until after 4K but would give another 50ish hp to both numbers. If I were tracking it***8217;d be a toss up but anything below track stuff and the 7163 is hard to beat.

[stealthlead]

Originally Posted by subydude

I’d take a 7163 for something fun on the street. Low 400’s on pump gas and higher 400’s on E85. The 7670 wouldn’t hit full boost until after 4K but would give another 50ish hp to both numbers. If I were tracking it’d be a toss up but anything below track stuff and the 7163 is hard to beat.

Thanks for the reply! I doubt the aluminum chra makes a huge difference anyways. Do you think it's a good idea to be seeking a twinscroll setup?

[subaru_gc8]

Originally Posted by stealthlead

Lower/mid power, I would be willing to sacrifice a bit of top end. It seems like these borg Warner's like to spool up pretty early which is why they're the top contenders for me. I guess these g series are competing against TS pretty well though. I should have clarified that this is absolutely not a daily driver.

can i ask how the car is used?

[subydude]

Originally Posted by stealthlead

Thanks for the reply! I doubt the aluminum chra makes a huge difference anyways. Do you think it's a good idea to be seeking a twinscroll setup?

Aluminum chra is really only if you’re trying to save weight. TS is nice and usually gives smoother boost onset but it’s more complicated and expensive. For a simple setup SS is fine.

[sense of nature]

Originally Posted by stealthlead

Do you think it's a good idea to be seeking a twinscroll setup?

Yessss!!
The difference is well worth any extra$$ or effort.
Smooth Linear power!

[stealthlead]

Originally Posted by sense of nature

Yessss!!
The difference is well worth any extra$$ or effort.
Smooth Linear power!

Thanks for the input! Have you had both single and twin? Both my tuner and IAG have tried to talk me out of a TS setup but everyone I talk to with one highly recommends.

[ADSubaru]

What a monster that will be

[T-37]

Originally Posted by stealthlead

Thanks for the input! Have you had both single and twin? Both my tuner and IAG have tried to talk me out of a TS setup but everyone I talk to with one highly recommends.

They're trying to talk you out of it for the reasons Subydude laid out above. People hear twinscroll and think they're getting the best of both worlds (quick spool and more power), and in general that can be the case. But for those specific turbos, the 7163 will spool faster (which IMO should be the #1 goal for a fun street car) and make close to the same power, for a lot less money. Good twinscroll manifolds/headers are very expensive.

[subydude]

I've ran both, and while TS is more expensive if you have the scratch I feel like it's worth it. I have a JDM TS manifold and VF37 on my 05 STi and it's really good. I've driven a TS 7163 on a 2.1 stroker and it was also very good. The difference in boost onset is the seller IMO, it's just smoother. SS tends to be more light switchy at the low end, which isn't bad if you're above that rpm all the time. In general you won't make a bunch more power, and full boost might not be more than a few hundred rpm sooner, but the transition to it and how it builds is very different.

I'm likely going to stay TS going forward now that I've had enough experience with it honestly.

[stealthlead]

Originally Posted by ADSubaru

What a monster that will be

Thanks! I've been keeping an eye on quite a few builds for a while. After seeing so many people just chase big numbers (as well as seeing engines blow up) I wanted something modest and unique.

Originally Posted by T-37

They're trying to talk you out of it for the reasons Subydude laid out above. People hear twinscroll and think they're getting the best of both worlds (quick spool and more power), and in general that can be the case. But for those specific turbos, the 7163 will spool faster (which IMO should be the #1 goal for a fun street car) and make close to the same power, for a lot less money. Good twinscroll manifolds/headers are very expensive.

I agree. Its kind of intimidating to have some of these big names literally telling me to scrap my plans, but I'm not trying to get a massive amount of HP here and spool the next day. Its just a street car I want to have fun with and not worry about exploding all the time. I feel like the 7163 should provide enough power for the application. I do understand the cost association, but the kits already been paid for and its just down to the turbo decision.

Originally Posted by subydude

I've ran both, and while TS is more expensive if you have the scratch I feel like it's worth it. I have a JDM TS manifold and VF37 on my 05 STi and it's really good. I've driven a TS 7163 on a 2.1 stroker and it was also very good. The difference in boost onset is the seller IMO, it's just smoother. SS tends to be more light switchy at the low end, which isn't bad if you're above that rpm all the time. In general you won't make a bunch more power, and full boost might not be more than a few hundred rpm sooner, but the transition to it and how it builds is very different.

I'm likely going to stay TS going forward now that I've had enough experience with it honestly.

You're definitely right, and its not that I have a bunch of extra cash on hand. I'd just rather do this once and do it right. Appreciate that input, having a smoother transition and slightly quicker boost seems like its worth it for me. It may be overkill and its probably not necessary for this application, but here I am lol.

[sense of nature]

Originally Posted by stealthlead

Thanks for the input! Have you had both single and twin? Both my tuner and IAG have tried to talk me out of a TS setup but everyone I talk to with one highly recommends.

I've run both & will NEVER run single again,in fact I'm converting my current set up to T.S!

[goneagain2011]

Running a EFR7670 twin scroll from ETS lots of extra items to run it, but worth it.
Boost builds quickly and great torque curve. It may not have great peak HP but for a
daily driver it is perfect.

[stealthlead]

Originally Posted by goneagain2011

Running a EFR7670 twin scroll from ETS lots of extra items to run it, but worth it.
Boost builds quickly and great torque curve. It may not have great peak HP but for a
daily driver it is perfect.

I'm right on the edge of getting either a 7163 or a 7670. You don't think it's too big for a DD? Did you go with biggest a/r?

[goneagain2011]

a/r 1.05

For DD have not had any issues, but have a lot supporting mods.
For street 7163 or 7670 will be fun, do not fall into peak horsepower war.

[stealthlead]

Originally Posted by goneagain2011

a/r 1.05

For DD have not had any issues, but have a lot supporting mods.
For street 7163 or 7670 will be fun, do not fall into peak horsepower war.

I'm definitely not trying to, honestly I don't really have an hp goal. But at the same time I don't want to limit myself. All supporting mods have/will be done including PNP'd heads, cams, CD blocks, dual pump hanger, 2000cc, etc.

[subydude]

7163 will do just fine. A wide and usable true 430 whp power band is considerably faster than a peaky 550 whp. And until you've been in a car with that much power it's hard to fathom.

[stealthlead]

Originally Posted by subydude

7163 will do just fine. A wide and usable true 430 whp power band is considerably faster than a peaky 550 whp. And until you've been in a car with that much power it's hard to fathom.

I didn't realize this but if I'm not mistaken, the 7163 is only made in IWG for the twinscroll version, and the only EWG option is an undivided one. That sucks :l

[subydude]

The IWG works fine on the EFR's. Run the high boost canister and you're good to go. Saves a lot of plumbing work and cost vs EWG on a TS setup.

[stealthlead]

Originally Posted by subydude

The IWG works fine on the EFR's. Run the high boost canister and you're good to go. Saves a lot of plumbing work and cost vs EWG on a TS setup.

But what about all of the boost problems? From what I understand you have to invest into a new wastegates actuator because the EFRs are notoriously bad for boost creep on their IWG setups

[subydude]

The waste gate canister (actuator) is less than $60 online: https://www.dieselpowerproducts.com/...BoCWtAQAvD_BwE

I don't have a ton of knowledge about the B2 frame, but the B1 does not boost creep at all and you need the high boost actuator to run more than about 22 psi. If the B2 is the same general idea, there's no issue with creep, you just need the stiffer actuator if you want to run higher boost.

Either way, less than $60 seems a lot cheaper vs two EWG's and the plumbing required.

[stealthlead]

Originally Posted by subydude

The waste gate canister (actuator) is less than $60 online: https://www.dieselpowerproducts.com/...BoCWtAQAvD_BwE

I don't have a ton of knowledge about the B2 frame, but the B1 does not boost creep at all and you need the high boost actuator to run more than about 22 psi. If the B2 is the same general idea, there's no issue with creep, you just need the stiffer actuator if you want to run higher boost.

Either way, less than $60 seems a lot cheaper vs two EWG's and the plumbing required.

That's true... Cumulatively it would save me $900 in piping and wastegates. I have also heard very good things about EFR's IWG once the actuator is used. Isn't it quite a bit easier to control boost with an EWG? Damnit you're making me reconsider an IWG now.... It would make sense as I hate the noise of external hence rerouting back into DP