GTX 2971R

[flyhigh]

Has anyone run one of these yet? It's time to go BT and after hours/days/weeks of reading threads, I can not decide which route to go. This model looks like it'd be pretty good for my DD (stock block) but I haven't seen anyone running it in a MS3 yet. Any thoughts?

I am installing the turbo WMI and GA at the same time and looking for 400whp for now, but want room to grow when the next bug bites and I decide to build it.

[zenit]

Why not a 28 frame, if you're going with the 71 compressor side?

Hell, you can now get a gtx2876.

[flyhigh]

Thanks for the input. I was hoping to continue supporting Stratified by buying the turbo from them, as they have been taking care of me, but they don't seem to sell that one (yet). Maybe @Lex; can shed some light on this new model. I'll look into it myself in the meantime.

[zenit]

Originally Posted by flyhigh Thanks for the input. I was hoping to continue supporting Stratified by buying the turbo from them, as they have been taking care of me, but they don't seem to sell that one (yet). Maybe @Lex; can shed some light on this new model. I'll look into it myself in the meantime.

I'm interested in hearing @Lex;'s thoughts, too.

As far as I know, 28 frame wheels are somewhat more efficient than the 29 frame, but flow less.
Gt28 - 68% max efficiency & ~20lb/min corrected turbine flow for the large a/r housing (0.84)

Gt30 - 72% max efficiency & 20-26lb/min corrected turbine flow for the 0.63-1.02 housings.


But- gt29 - 64% max efficiency & 20-24 lb/min corrected turbine flow with the 0.63-0.84 housings


So, yeah, the 29 frame flows similar to a 30 frame, but is less efficient than either the 28 or 30 frame. I don't see how it would out preform a small housing (0.63) 30 frame, given the drop in efficient flow.

Then again Honeywell/Garrett engineers are smarter than I am, I'm just not seeing their intentions here.

[mituc]

Stratified can get you whatever you want from ATP even if they don't have all the kits listed, so if it's not on their web shop just ask them.

On a stock block you have several options which eventually boil down to two turbo sizes:
1. BNR S3/GTX2867/GTX2871 which spool rather quick and can flow about as much as a factory block can handle (less the high mid-range torque and torque ramp-up);
2. BNR S4/CS/GTX2971/GTX3071 which can easily overpower a factory block while still remaining within their efficiency island, and with these the high torque at low RPMs (at least in gears up to 4 where the boost doesn't have enough time to build if you step on the gas at a too low rev).

It ultimately comes down to what you like more. I went with a GTX3071 and would not go back to a smaller frame turbo. I like the progressiveness of the boost build as well as it's relative slowness which keeps me away from ending up in massive uncontrollable wheel spin even in 1st or 2nd gear, while the spool and boosting are not slow at all and city driving doesn't suck at all even at <3500rpm.

You can as well go with a smaller frame turbo which will not have the violence of the hysterical factory turbo bull will still be quite hysterical themselves providing awesome response in the midrange (2500-3500rpm).

Either way, whatever you get can overpower the factory block, so it's all about the midrange response. You should ask Lex as well, since you worked with him he may already know your style and needs and can make a recommendation based on that.

Otherwise we can only tell you how these are like, then it's up to you to decide. On a stock block that wants to remain stock I recommend a GTX2871, plus a WMI kit to inject only for knock protection and slight octane control (a 300-400cm3/min should do).
If you intend to build your block within the next 30-40k miles go straight for a GTX3071, or even a GTX3076 if you already have an aftermarket exhaust manifold and eventually aftermarket IM.

[flyhigh]

Thanks for the info. I don't want to make an expensive investment and end up not liking it. I'll wait to hear back from the fine folks at Stratified to see what they suggest for me. @Lex; seems to always be right. I really appreciate the info both you and @zenit; provided.

[zenit]

I'd also poke around other forums and see if there is a consensus/trend in what people think of the 29 frame.

[MD1032]

Originally Posted by mituc On a stock block that wants to remain stock I recommend a GTX2871, plus a WMI kit to inject only for knock protection and slight octane control (a 300-400cm3/min should do).

A lot of people these days come around here looking for 400 whp but I really question how much they're in love with that number. If you can put up with 380, you can easily get there with an $800 used S3 and some E85. Easy and cheap. Speaking about the 3071 in particular, there's no way I could tolerate an extra 400 RPM lag just to put another 20 whp on the board for my car. It really wouldn't make it any more or less effective.

The reason I recommend the BNR turbos is solely based on cost. The ATP Garretts are horrifically overpriced (over double the cost in some cases) and are crippled in the top end by their poorly optimized hotside, which also happens to have boost creep issues with the 30 frame variants. The ATP Garretts are effective, and superior to the BNR turbos, but only barely.

[Jeff23spl]

A friend installed a gtx2971 last year on his stock block...He has meth and got a tune by a well known tuner of this board but he still went into a blown ring land issue few months later. So definitely, it is large enough to destroy stock internals.
Turbo spool was similar to my gt2871 but probably with more top end. I just drive it before the tune was finished so it felt slower at that time. Final dyno above 400whp brings me to wonder if i need to change mine too...

A thing to consider on top of turbo spool, a large compressor coupled to a small turbine will make lower lag but lower top end power and all that at higher pressure and higher BATS. Looking at more octane or knock...

At the end, if you don't plan for engine rebuild, i would choose a smaller one like a gtx2867 but if you don't care to build the engine and you don't want to replace the turbo soon, the gtx2971 might be nice for DD but as MD said, it isn't cheap...

[VoodooJef]

I`m also looking at the 2971 for much the same reasons and feedback on it is pretty scarce for this platform. Going for the 400hp benchmark, then pistons and rods to ensure a safe 425 for as long as I own it (well, as far as I could expect anyway), and maybe even a bit more down the road. There`s really no effective reason to take this car over 400 other than bragging rights but it`d be nice to know I`m not pushing it hard at all at 425 and the internals will last so long as I take care if it properly.

[mituc]

Originally Posted by MD1032 The reason I recommend the BNR turbos is solely based on cost. The ATP Garretts are horrifically overpriced (over double the cost in some cases) and are crippled in the top end by their poorly optimized hotside, which also happens to have boost creep issues with the 30 frame variants. The ATP Garretts are effective, and superior to the BNR turbos, but only barely.

As I stated, there are options for everyone and every taste. In my case for a FWD daily the too fast response of the smaller frame turbos may be a bit too much if you're under 50mph/80Kmph even on clean asphalt. On a MS6 the situation is different thanks to the AWD.

Originally Posted by VoodooJef I`m also looking at the 2971 for much the same reasons and feedback on it is pretty scarce for this platform. Going for the 400hp benchmark, then pistons and rods to ensure a safe 425 for as long as I own it (well, as far as I could expect anyway), and maybe even a bit more down the road. There`s really no effective reason to take this car over 400 other than bragging rights but it`d be nice to know I`m not pushing it hard at all at 425 and the internals will last so long as I take care if it properly.

At 400 crank HP even with meth injection the ringlands of the factory pistons are on borrowed time. You can run the factory engine until you crack ringlands and rebuild from there, but don't aim for 400hp and hope for the best simply because these pistons cannot handle the heat of 400cp for too long. of course it also depends on how often you ask for those 400hp and for how long.

[VoodooJef]

Originally Posted by mituc As I stated, there are options for everyone and every taste. In my case for a FWD daily the too fast response of the smaller frame turbos may be a bit too much if you're under 50mph/80Kmph even on clean asphalt. On a MS6 the situation is different thanks to the AWD.

Even being fully tuned on E85 now I`ll boil the tires if I lean on it hard at 40/50 in 3rd with the crazy spool of the K04. 1st and 2nd gears are really more for comic relief if I`m horsing around.

Originally Posted by mituc At 400 crank HP even with meth injection the ringlands of the factory pistons are on borrowed time. You can run the factory engine until you crack ringlands and rebuild from there, but don't aim for 400hp and hope for the best simply because these pistons cannot handle the heat of 400cp for too long. of course it also depends on how often you ask for those 400hp and for how long.

Methanol can really keep combustion chamber temps down a LOT. My plan, be it as it may, is to be able to do 425 on a moderate tune and have the methanol more as a temp buffer vs power depending on it. There is of course a line to be drawn there, limitations of the DISI fuel delivery and all. Engine safety first, then I`ll start inching up the output to more courageous numbers. Hell, I`m already eyeballing a 5th port setup. But we`ll see. Time and money will determine how it unfolds, but no matter how it goes I have to keep engine safety in mind the whole way. And I`ve said it before...I don`t need nor want another 600hp daily driver.

[mituc]

Originally Posted by VoodooJef Methanol can really keep combustion chamber temps down a LOT. My plan, be it as it may, is to be able to do 425 on a moderate tune and have the methanol more as a temp buffer vs power depending on it.

Methanol will increase the octane of the mixture, will burn a lot more predictable and cleaner therefore it will prevent detonation. It's the water in the mix which cools down the cylinder during the exhaust stroke.
On the other hand when adding aux fuelling people also tend to increase boost and make up for the excess of heat addressed with WMI.

As for 425 crank on a stock block... good luck. You'll need a bit of aux fuelling for that as well. I'm talking here about usable numbers, every time everywhere, not just an isolated dyno session or a single vdyno pull. If you only want to get that number once and then push the acceleration pedal with fear then ok, your "425hp build" will last for quite a while.
We've had here on the forum stock blocks (2?) which made past 500hp and lasted about 6 months.

[flyhigh]

Thanks again for all the feed back everyone. I am keeping the block stock for now and don't believe 400hp will cause any problems, but I do not want to have to change out the turbo again if I decide to build the engine later.

After looking around the webs for a bit, it seems that @VoodooJef; and myself are the only people on the planet currently looking to see what the GTX29 can do for the MS3. I do not want to be the guinea pig here so I'm waiting to hear back from my tuner to see if others have done this and how it performes/performed.

I would like to get away from the comic relief of 1st and 2nd with the K04 mentioned above. I would prefer a "slower" spool with power going to the road over instaspool and new tires every 3 months.
@mituc; did going with the GTX30xx slow the spool enough to bother you, or just enough to keep you from wheel-hopping down the road?

This is why the GTX29 peaked my interest ...Happy medium??

[mituc]

Originally Posted by flyhigh I would like to get away from the comic relief of 1st and 2nd with the K04 mentioned above. I would prefer a "slower" spool with power going to the road over instaspool and new tires every 3 months. @mituc; did going with the GTX30xx slow the spool enough to bother you, or just enough to keep you from wheel-hopping down the road? This is why the GTX29 peaked my interest ...Happy medium??

Those situations when I'd like a better response are rare but I can't say they are non-existent. I knew what a 3071 is about and I kind of accepted the situation right away, and I also learned how and when to push the throttle so that I don't get into those semi-bothering situations when I'd like to have what I can't. I also knew that the GTX3071 wasn't as bad spooling as a GT3071, so that was reinvigorating at the time.

The 2971 should be right in between 2871 and 3071 in therms of boost and top-end. I know Lex tuned a few STs with this turbo but I'm not sure about any MS3s. Also, I don't know what would make more sense, a GTX2971 or a 2876? And if both 2876 and 2871 can overpower the factory block but the 2871 has a slightly better response below 3700rpm then why not get a 2871 instead? Tough choice, see?

From a practical standpoint, on a stock block a GTX2871 may be the most logical choice between the two though, but it's still a tough choice:
This is why:

1. a GTX3071 has more top end which you will never be able to exploit at its full for various reasons (you need a better radiator, WMI, full exhaust, and you will do all that you'll realise you can crack a piston or a rod any time if you push the whose setup to its full potential);
2. a GTX2871 will also have the possibility to flow more than what the engine can handle up top but with a bit more heat (more boost therefore more heat for the same amount of air) but will return you the 3200-3500rpm range which is where the GTX3071 starts having some usable response. So with careful tuning and paying attention to how the boost and torque ramp up in the 2800-3500rpm range there's no chance you will throw rods.
3. if the <3500rpm range is not an issue (the GTX3071 can boost at 18PSI even at 2400rpm, just that it needs time, that's we're discussing about the response), then once you're boosting the GTX3071 may get you a bit more and safer power at the same airflow simply because of the lower BATs. Also, above like 3800rpm GTX3071 has a more or less instantaneous response, and if you start accelerating from, say, 3200rpm, even in 5th you'll be at 3500-3700 in no time and boosting as you like.

However, no matter what turbo you chose the high rpm/high boost situations may soften the ringlands over time. therefore my recommendation about using a WMI kit even with a small 200-300-400cc/min nozzle still stands. I'd tune on pump gas or whatever fuel you can get in your area, then tune for WMI slightly adjusting the AFRs and timing but leaving boost alone. If you chose a professional tuner he will know what to do.

My previous recommendation about checking with your tuner about the turbo also stands. You'll probably go through some kind of a mini interview "what do you want? what would you like more between this and that?/I like this more over that, and I'd like to use the extra power like this" - done.

P.S.: here, this may help you decide. An image or a movie make more than 1k words. This is how my GTX3071 responds. You will not make that power on a stock block but the response should be similar having in mind lower torque and power.
https://www.youtube.com/watch?v=zIL4h5Mw5oM
If you think it's kind of bad when starting at around 3300-3500rpm then get a 2871 and never look back. You can't go wrong with any of these turbos anyway.
By comparison this is the same car when my engine was stock. I actually broke ringlands on #2 and #3 after I raised the rev limit to 7000 as you can see in this videoclip:
https://www.youtube.com/watch?v=V4Co8D1AdzY

[flyhigh]

First, apologies for the fact that the thread title is now deceiving.

So I've decided to go with the BNR S4 over the GTX2971. There were several reasons for this, but mostly it was $ and the fact no one here has done it yet.

I hope some of you will take a look at my sig and let me know if there is something missing or something different you would do at this stage.

[sharksinspace]

I don't now what size that CP-E intake of yours is, but you'll probably want a 3.5" for the S4, especially if you go v2; you'll also need a new MAP sensor. Catless DP will let it breathe better, too, if changing that out is a reasonable option for you.

[Jeff23spl]

I don't see a 3 (or 3.5) bars map in your sign ? the stock 2.5 won't work above 22psi
Did you got a 3.5'' turbo inlet pipie? You may need to relocate the pcm or reduce battery size to fit a full 3.5'' intake. Maybe an adapter but you would benefit from a larger intake...(I personnaly run a silicone one of 3 or 3.25'' (I don't remember) and i just removed the PCM protection plate to fit it but the silicone core is looking a bit oval shaped once installed there....)

Same for the MAf hosing, if your CP-E is 2.64'' ID like the stock one, you may come close to peg the MAF at 4.9x volts during cold days...

[mituc]

I've ran a Cobb SRI (which is about 10-12% larger than stock judging by the CL fuel trims and ) up to about 26PSI and 350-355g/s of air. It's do-able with with quite a bit of stress on the turbo I guess.

[flyhigh]

Thanks guys.
I missed a few things in the sig. Fixed.
The cp-e intake has a 3.25" MAF housing
GA has a 4 bar map sensor
I got a JBR 4"->3.5" reducer for the TIP to turbo connection
I'm in S. Florida....dreaming of cold days
DP is still silver (on the outside) and too new to replace at the moment

[Jeff23spl]

you should be fine then.

[Jeff23spl]

Originally Posted by mituc I've ran a Cobb SRI (which is about 10-12% larger than stock judging by the CL fuel trims and ) up to about 26PSI and 350-355g/s of air. It's do-able with with quite a bit of stress on the turbo I guess.

You were probably close to max voltage. I could even work with all stock intake parts but...

I tested it myself that bigger is better for the intake lol

I installed the gt2871 and i kept the Aem/mazdaseed accessory intake at first when it was still cold outside. I was able to reach the max flow of the maf. To make it worst, i was using a kind of coupling reducer with a 2''ID that was making turbo surge at spool... (I stupidly used what i had in hand at that time)

Later i installed the 3.25 maf hosing with all larger pipe, it was like upgrading the turbo again...

[VoodooJef]

I also opted out of the 2971. My S4v2 showed up yesterday. Would have liked to have something a little more unique but I couldn't justify spending almost another grand on it.

Sent from my LG-H830 using Tapatalk

[flyhigh]

Parts are almost all here. Just waiting on the GA. Install day in 1 week!!
Scanned_20170307-1520.pdf

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Copy of Scanned_20170307-1514.pdf

[VoodooJef]

Nice! Same turbo and methanol kit going in mine on sunday.

[flyhigh]

GL, sir. We'll have to compare dyno #'s once everything is tweeked. You going with eth too?

[VoodooJef]

yep. Been on it for a bit now. I like how the car runs on it, and I`ll take all the alcohol fuel I can get in the damn Texas summer.

[sheston]

You should try some Meth in the tank. I use 2 gallons per fill up for the texas summer

Works for me better than 4.5 gallons E I was adding

[VoodooJef]

Originally Posted by sheston You should try some Meth in the tank. I use 2 gallons per fill up for the texas summer Works for me better than 4.5 gallons E I was adding

Ethanol in the tank, methanol spraying as well. BATs should be plenty chill

[Jeff23spl]

Originally Posted by flyhigh Parts are almost all here. Just waiting on the GA. Install day in 1 week!!

Nice stuff! I use the same TIH, take a double look when you tighten it to the turbo to make sure the back isn't slipping off...(happened to me once since it is a bit squeezed beside the battery)

Which brand is your OCC ?

[flyhigh]

Thanks for the TIP
OCC is from Kozmic. Looks pretty nice, and of good size. 1 imperfection (slightly burned) on 1 of the welds which pissed me off just because of the price of the thing.

[jdmluvin]

I'm battling with the same turbo decisions you guys were earlier in the thread. Currently on the stock block but would like to build it soon, hopefully next winter. I was considering the 29 for a while but I think I'll end up going with the gtx3071r. I haven't purchased it yet and as we all know turbo decisions are constantly evolving in our heads. I enjoy auto x so i'm a bit worried about the response on the 30, but I don't think it will be a deal breaker considering the power potential and temps. tr8 and jbr front mount piping and crash bar are on the way, just need a downpipe and boost controller then on to the turbo! Lots of good info in this thread, thanks guys!

[mituc]

Originally Posted by jdmluvin I'm battling with the same turbo decisions you guys were earlier in the thread. Currently on the stock block but would like to build it soon, hopefully next winter. I was considering the 29 for a while but I think I'll end up going with the gtx3071r. I haven't purchased it yet and as we all know turbo decisions are constantly evolving in our heads. I enjoy auto x so i'm a bit worried about the response on the 30, but I don't think it will be a deal breaker considering the power potential and temps. tr8 and jbr front mount piping and crash bar are on the way, just need a downpipe and boost controller then on to the turbo! Lots of good info in this thread, thanks guys!

If you will be above 3500rpm on the autox course then a gtx3071 will serve you well. But for autox only I think an S3 or a gtx2871 may be what you actually want.
A GTX3071 is extraordinary for circuit racing though.

[MD1032]

To be honest, for autocross, anything larger than a K04 is going to cause you to lose a lot of laptime. It's just a question of how much. Unfortunately the S3 really is the smallest aftermarket option we have, and it's not even really that small.

[Jeff23spl]

is not the bnr S3 like a bushing gt2871 ?

You can have the GTX2860 that is just slightly bigger than the k04 and machined wheels https://www.turbobygarrett.com/turbo...tx2860r-gen-ii

and there is also 63 and 67mm wheels not always offered with all models and ATP hotside but maybe you just need to ask...
https://www.turbobygarrett.com/turbo...tx2867r-gen-ii

All of them should spool faster than a gt2871...

[mituc]

Originally Posted by Jeff23spl All of them should spool faster than a gt2871...

We also have GTX2860 and 2860 as an option, but these would perform like a BNR S3 I guess, or even less, so I'm not completely sure that is going to be a real update.
Unless someone is autocrossing weekly for such a small turbo "upgrade" to make sense I'm not sure it worth it.
A 3071 though transforms these cars quite a lot and despite the slower and later spool the power curve becomes manageable and useful from around 3000rpm even in lower gears as wheel spin is not that much present any more.

[Jeff23spl]

I agree, i would choose a 3071 anytime over a 2860. That 2860 is a shy upgrade but according to garrett, the gen2 is rated for 475hp...not bad for autocross maybe...

[flyhigh]

Just added JBR small battery tray and Optima 51R battery to the list. Figured it would help make putting everything back together a little easier. Hope they get here in time for install day...

[jdmluvin]

The 3071 is definitely too big for auto x and I know it will lose me a lot of time, but I'm just in it for fun anyway. The classes I'm stuck in will not allow me to be competitive. I also plan to road race and drag race the car which is why the 3071 will likely be my choice, that and the pursuit of too much power! I have a civic that will be more competitive in auto x if I ever finish it, and then the mazda will be drag oriented so I think in the long run I'll be happy with the larger one, but in the short term a smaller one may suit my needs better. I would hate to have to buy a turbo twice. I really just wish the k04 wasn't such a turd!

[zenit]

Originally Posted by jdmluvin I really just wish the k04 wasn't such a turd!

Wish granted. It's not a bad turbo.