Big Turbo Reliability

Hi all,

Reliability is paramount in my new build. I am contemplating three different turbo options:

BNR S3
BNR S4
GT3076R (used, but same price as the aforementioned BNR kits)

I am ignorant, but I figured the S4 would be a great fit since I can have it tuned for lower psi and only really have it work higher up in the range, thus keeping my stock internals happy. Am I correct in this assumption, that a tamed S4 would be a great fit for a reliable turbo - or is the greater volume of air playing a larger part in this and I'd be better off sticking to a lower tier or CST4?

Thanks all!

 

Remember cst4 is comparable to bnr s3 in size not the s4. If you're wanting to stay stock block and fueling the s3 is a perfect fit, there's many threads on the differences in my opinion for what you want the bnr s3 or gtx2867r will win every time.

 

Thanks for the info!

Is there any validity in the S4/3076 claim (or other comparable alternatives) and having it tuned more conservatively? I plan on sticking with this new build for a long time to come and ultimately want the most reliable build (short of forged internals)

 

if you dont plan on building your motor and doing some extra fueling then in my opinion its not worth it, the S3 will max out stock fueling before you max out the turbo. S4 is worth it when you plan to go further.

 

I agree with Awa. If you don't plan to run extra fuel or a built motor you should stick to a smaller turbo than the s4 or 3076. They are 500hp capable basically and you would lose spool time and not need what it offers. My vote would be gtx2867 if you could afford it instead of the s3.

 

fixed 2867* not 76 that's a big side on the turbo

 

Putting on a bigger turbo and detuning it is going to give you all of the shitty parts of having a big turbo ie lag and none of the payoff with big power.

Besides underusing the turbo only saves wear on the turbo not the motor

 

Well and maybe a very slight increase in mpg as it will not be in boost at the lower rpms but that's about it.

 

That's a strong case for the S3!
Thank you all very much for your insight. It's all greatly appreciated.

Any benefit of going with the 2867 in terms of reliability under daily driving conditions, over the S3?
They're separated by a good chunk of change, so I'm curious if it's worth the extra coin.
I have a 3.5" JBR intake I plan on running alongside the new turbo, and maybe exploring some exhaust options and an aftermarket TMIC (looking at the Corksport one). I don't see myself doing anything past this point in the quest for power as that's all plenty for a daily.

Given that I've made two K04's last me until 300k, I'm confident that anything else will probably give me decent long term results.
For this reason, I'm leaning more towards the S3 at this point, but perhaps there's more to it that I'm missing.

Thanks guys!

 

gtx2867r is anti surge ported, dual ball bearing and will out perform the S3 which is a journal bearing turbo, as for engine reliability it's a pick whichever apple you like better scenario, if you have the money to pick up the gtx2867r it's the better turbo all around.

here is some info on bearings for turbos; https://www.turbodynamics.co.uk/tec...driving a vehicle with,quicker 0-60 mph speed.

as for TMIC; ETS>CPE>CS. you're going to get better performance out for ETS/CPE than you would the CS, unless you want to retain the stock shroud for CARB "barf"

 

Thanks for that info! I’m going to be reading up on a lot of this later this evening.

I currently only have the OEM exhaust setup; should I consider replacing that if I decided to go the GTX/S3 route?

 

Even if you went with a quiet exhaust I would upgrade that with the turbo. The downpipe is your biggest bang for buck upgrade on the whole bolt-ons list so if you want an easy 20hp then there it is

 

Alright then, sounds like a plan!
I'll look into getting a decent catted DP and maybe upgrade the catback along the way.

Seems like the S3 is a good fit for what I need, but there a couple of things the S4 has that sound enticing, like the anti-surge compressor housing, a 3.5" compressor inlet and the GT30 turbine wheel. But seeing as how I can manage to make a K04 last, I would probably do fine with a S3, so I'm not sure...

Is it really that bad of an idea to get the S4 and tuning it conservatively? I'm not asking that rhetorically - I'm genuinely curious. I've been scouring the forums and the only thing I see is that the S4 kicks in a bit later and has more headroom (plus the things I mentioned above). I don't mind what sounds like marginally more lag, especially since it might even help keep my bottom end from taking a lot of brute.

I'm also ignorant and know very little about these things, so I truly appreciate your guy's input. Thanks a lot everyone!

 

Wut the S4 doesn't kick in faster, why is a gt30 wheel enticing, and a 3.5" inlet? None of those matter for what you're after 3" maxes stock fueling just fine plus if you pair the 28 with a 67 then it's a great match that works wonderfully with the turbo. If you want anti Surg porting then go buy the gtx2867r

We've already told you the draw backs and benefits! Running a bigger turbo doesn't improve reliability of the engine and on stock fueling you're not maxing out the s3 so it's going to last just fine without the decreased responsiveness that comes with upsizing.

You just asked the same question again...I've answered it again...go back and read the thread seems like you want us to be like "it's k g bigger" well for you bigger isn't better but of you want a bigger turbo that will spool slower and at higher rpms then go for it, it's.your car but I wouldn't do it to mine, there's a reason that bnrs3 and gtx2867r is the go.to turbo for stock blocks and fueling because it's almost perfectly matched and responds wonderfully with great longevity for turbo and engine if tuned correctly (freektune or purple drank - don't go with dramatune).

 

I never said it kicks in faster...in fact, I said the exact opposite and asked if this would have been advantageous for my needs, seeing as I'm still on stock internals. The differences seem to be only marginal, but it sounds like the S4 produces more results higher in the rev range. 300rpm lag in exchange for more power on top doesn't sound like a terrible exchange. I know it's not preferred for most, but I was more curious as to why this was bad, as opposed to just being different. It's very likely that I'm ignorant of some other downside to this setup, so naturally I wanted to ask you guys who know more than I do.

I've been reading through threads from people who have had experiences with the S3 and S4, and a lot people seem to prefer the S4's delivery. I don't know if I can link to other forums on here, but here's an example from one owner:

Now the "superior" claim is totally subjective, but it's just an example of how the setup works for some. There are a lot of owners who said similar things, with many preferring the quicker spool of the S3 - I just shared that one as an example.

But your last reply gave me a solid answer. I really appreciate your time and consideration - I'm still learning about these things, so it's all greatly appreciated. I apologize if my stubborn questioning came off the wrong way.

Have a great day

 

I guess I can drop in...

I have a BNR S4 v3. Been on the car since Dec 2018, about 45k miles now, 90k miles on original OEM engine, tuned by Rob @ Hypnotic at the time.

I was on the fence between the BNR s4, Garrett 3067, and even the efr 7163. For my own reasons went with S4.

Lag over k04 is less than 500rpms. When the turbo starts pulling it pulls its pulls fast up to 4k rpm's, and from there it pulls hard as hell until I run out of fuel since I am on stock fueling. That reduced wheelspin over the k04 makes the car much easier to drive and control.

Big appeal to me was reduced initial torque for OEM rod life, and potential for long term growth. I told Rob not to nuder my tune, because I wanted the extra pep especially since I went with the bigger s4. Also COST! However not referring to turbo price, I mean added cost of additional shit such as gaskets, hoses, heat precaution, supporting mods, etc. It's easy to order OEM gaskets from Edge, Mazda, or local shops. Sourcing gaskets for other flanges can be tricky if you are looking for specific materials or less common flanges. Also keeping stock flange gave me options for different parts all based around the same model, OEM. I am picky so I mix and match parts.

As for power, I love it! Calm when you need it, fast when you need it. It should be noted that I have a full race exhaust manifold, catless CPE downpipe, COBB catback, ETS TMIC, Synapse BPV, JBR 3.5" intake and supporting sensors. In FL @ sea level, using 93 octane.

EasterBunny is right about detuning big turbos, you save the turbo and not the engine.

 

I forget about early rpm traction problems since I have a 6 so that's a good point too though. Glad you gave your experience man Sounds like S4 is a great pick bro!

 

I really, really appreciate you dropping in! This is very similar to what I've read from others who went S4, many whom had S3 before the install, and it's the same points I was making about how it delivers its power over the S3. Looks like you started your search very similar to mine - I also have a JBR 3.5", upgraded TMIC, and looking at picking up a catted DP and 3" catback to accompany the new turbo.

I already know it has more lag than the S3 (looking at some dyno runs, it didn't look like more than 300-350rpm, or under 500 as you said), but it seems to have a lot more room under the curve and pulls hard up in the range. I drive fairly conservatively since the MS3 is my daily, so if I need to go somewhere, it's usually to overtake or get on the onramp - and I never go WOT under 3200rpm in the car anyway, because stock internals and wheel spin.

This is the thing I'm really curious about, and what prompted this thread to begin with. Would a conservative S4 tune produce more wear on an engine than an optimally tuned S3? Because if it doesn't, then a detuned S4 doesn't produced any further wear on the engine than the S3, but also manages to decrease its own wear as a result? And all I pay for that is a marginally later spool and the extra cost associated with the purchase?

Surely I'm missing something here - you guys know far more than me!

Thanks again!

 

No
Yes
Potentially

You are not wrong in your assumption, however both scenarios translate to different throttle response.

You need to figure out what your goals are long term. What I mean is long term support mods, and goals for the car. If you will never track it, and only daily drive it, get an s3 or gtx2867. If you ever plan to track it, drive it over 90mph for extended periods, supplement fuel, or tear into the engine for a rebuild/upgrade, then get an s4.

With support mods like a good exhaust manifold, downpipe, catback, and heatshields, your s3 will still spool fast, and you will increase the volumetric efficiency of the engine. Meaning better fuel burn, cyl evacuation, and top end on the s3. It won't ever hit 500hp but it will flow a lot more up top, than without support mods. That'll put you close to 380hp. 380hp is a lot for this FWD, 6spd, short geared car. Your power will always be there, you will shift like you do now, and throttle response will be similar to stock but smoother power delivery.

With a detuned s4, the car will feel like a dog. The lag will be worse, and it'll feel like you never get a full breath from the turbo. Will you have power? Sure, but it won't be immediate or smooth, you will need to mash the pedal all the way down all the time, which can make driving goofy.

With all my support mods, ceramic coats, and heat wrap/blanket, my spool is close to a k04, but turbo efficiency is around 4k, that's where you have power. With the S4 and my mods, I never need to go full WOT. I can stay in gear longer, so driving around town I cruise at 3.5k rpms. If I need to move fast I throttle until 6.5k before I shift. So I gained the feel of taller gearing, think like a v8 with a 4spd.

I have a lot more support mods that I won't list cuz lazy, but they are all for cooling and endurance, so when I need to move and stay in power, I don't worry about overheating or failures.

So again, support mods and long term goals. Do you want to keep shifting around all day trying to find power, or do you like the feel of the k04 and how it is immediate?

 

What you are missing is that everyone in this thread is telling you it's a terrible idea.

Higher cost and worse spool with no upside.