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Old 11-30-2013, 07:03 PM   #1
aristg
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Question GTX2867R or GTX3067R T3 flanged ?

The case: B21ET with 531 head, B23 intake, 90s Mitsubishi exhaust manifold ported to T3 flange, A cam, 3 inch downpipe then 2.5 inch with no mufflers or cat and Kjet. The car has no electronics at all, so no knock sensors etc just a wideband

The question for turbo experts :

Which Garrett would you suggest for this setup? GTX2867R or GTX3067R ? These two are identical on compressor side, however the size of the turbine wheel is different. I am looking for AR .63 turbine side for both of them

The main parts (ATP site) for the two cases are:

GTX2867R -> GRT-TBO-187 & ATP-HSG-004 & ATP-WGT-023

GTX3067R -> GRT-TBO-260 & ATP-HSG-037 & ATP-FLS-075 or second option ATP-HSG-075 (but it is .72 A/R so may not be an option after all)

I am only interested in terms of performance, so do not judge by price. All of them will be internally wastegated and there is no restriction on choosing any of them.

Would the 3067 be much more laggy than 2867? Would my displacement be appropriate for the 3067?

For my setup boost adviser on Garrett's site calculates pressure ratio of 2 and corrected air flow mid revs 18 and max revs 24. The goal is about 280-300hp .. maybe cant be achieved but .. its something to hope for
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Old 11-30-2013, 07:22 PM   #2
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Look on garretts website, they have horse power and displacement ratings on every turbo. Depending on your goals, either one could work.

I really liked the response on my GT2871R on a lightly modded B230FT. Also, duder is a member on this site who works for garrett/honeywell, maybe he can weigh in on this.
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Old 11-30-2013, 11:19 PM   #3
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You could always look into a BW200sx if money comes into play. 2871R is a sweet turbo.
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Old 11-30-2013, 11:42 PM   #4
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@Lando both of them cover my displacement & horsepower goal .. so .. what next ?

@centason it is said that GTX2867 is about the same with 2871R @ low pressures but the GTX is much more efficient @ high pressure. More than that the compressor of the GTX2867 is the same for GTX3067 so everything is on the turbine housing .. which is the detail that makes the difference ;)
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Old 12-01-2013, 06:04 PM   #5
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Someone to guide me between these two ??
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Old 12-01-2013, 06:20 PM   #6
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It really depends on how well the car is breathing, compression ratio, and how much fuel you got. Then you create more exhaust to spool a bigger turbo. Fix to that though is a divided housing. You want the sweet spot at a certain rpm with as little lag as possible. The hotter and faster the exhaust can move the faster you can get a turbo to spool.
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Old 12-02-2013, 08:02 AM   #7
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You should contact Duder (his username here) He works for Garrett and can point you in the right direction.
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Old 12-02-2013, 07:55 PM   #8
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You rang?

This is an interesting question and one that I'd really like to see data for. Unfortunately there aren't any good test results (that I know of) showing a back-to-back comparison of the GTX2867R vs. GTX3067R on the same engine.

It's not exactly an apples to apples comparison since the turbine wheels are of two different designs, and the available turbine housing options are different for the 28 vs. the 30.

In general, irrespective of size, the GT28R turbine wheel aero design (blade and hub geometry) is more efficient than the turbine wheel design used in the GT30R and larger. If you scaled up a GT28R turbine to 60mm, it would outperform the GT30R. However, what's known as the "wheel speed match" is better for the GT3067R vs. the GT2867R. Given the same compressor stage, which is true in this case, going to a larger turbine wheel means the entire turbo will be more efficient.

For the same boost pressure, both turbos in this comparison would be at the same speed. At 2.0 pressure ratio, lets just say the compressor is operating at peak efficiency of 79%, around 33 lb/min and 105,000 rpm. A 60mm (GT30R) turbine wheel will be more efficient at 105krpm than a 53.9mm (GT28R) turbine wheel at the same speed, all else being equal. The complication is, for various reasons that all else is not equal because of the two different turbine wheel aero designs. But let's just say that the GT30R is more efficient at this operating point. The effects of that are:

-Lower exhaust backpressure (less turbine expansion ratio is needed to make the same shaft power)
-Improved VE / flow through cylinder head (because of lower restriction on exhaust side)
-Higher engine power output at the same boost pressure (due to improved VE)

The other thing to consider is the twin-scroll turbine housings that are available for the GT/GTX30R family, but not the 28 (not yet, anyways). A twin-scroll housing with a proper equal length, divided manifold, pairing cylinders 1&4 together and 2&3 together, will take advantage of scavenging and pulse energy to help the turbine spool up more quickly at low engine speeds.

Personally I am just about decided that I'll go with a GTX3067R on my B230FT 8-valve build, with a divided manifold and a new Garrett twin-scroll v-band housing. There is also a new twin-scroll T3 housing if you don't want the v-band option. ATP sells them, along with a weld on inlet adapter for building the manifold from. My guess based on the data I have available to me is that the GTX3067R w/ twin-scroll will outperform the GTX2867R single-scroll - in both spoolup / transient response and also power potential.

I had an Australian guy come up to me at the SEMA show last month and tell me how much he loved the GTX3067R, twin-scroll on his 1.6L Miata. He said that turbo woke the engine up and changed its character completely. He claimed huge power and almost instant spoolup (2500 rpm IIRC) but I didn't see proof so I'll take it with a grain of salt. Regardless, this guy loved it and his engine was much smaller than our redblocks are, but likely flowed similarly given the 16 valve head and higher rev limit.

The main situation that I'd suggest a GTX2867R over a GTX3067R would be upgrading from another GT28, because you can keep the same turbine housing. Or if packaging space for the turbo is extremely tight and a GT30R turbine housing won't fit. If you're stuck on internal wastegating, and won't do twin scroll, then it may be a toss-up in terms of performance between the two. You can't really go wrong either way though.
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Old 12-02-2013, 08:43 PM   #9
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Listen to the man.

I will say this: I had a 63 AR 3071R T3 on my old T5R and I couldn't imagine a better daily driven turbo for the 400-500bhp range. The car with an EBC was flat out impossible to drive uphill without speeding (the car made so much torque and spooled so easily that you'd be doing 95 in 5th uphill before you realized it).

Gary has a 2871R with LH2.4(?) and an AW71 and it's really fantastic. That's the perfect turbo for an auto DD car IMO.

I think for the 245 though I'm going to go .82AR GTX3076R based on Duder's recommendation.

NOW for K-Jet, I wouldn't recommend either of them. Honestly, a 15g-19T would be the easiest solution and will keep up or outpace what K-Jet is capable of (with out serious mods) for a great affordable option.
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Old 12-02-2013, 08:44 PM   #10
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forgive my ignorance Duder, but wouldn't both of those turbos be 'overkill' for a 300Whp goal. I agree that they will perform amazing well, but won't they leave an excessive amount of head room?

People have been talking about the larger td04HL turbos (18t, 19t) making 300hp, I always think of the GTX series turbos as pushing a massive amount of air. Is my impression wrong?

I'm gong to brush up on my compressor maps and lbs of air to SCFM, and all that, but 33lbs/min is in the "serious business" airflow range.
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Old 12-02-2013, 09:02 PM   #11
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Not sure if the OP was saying 300whp or 300bhp (at the flywheel). I'd say 300 whp ~= 350 bhp roughly. But yes, you are correct that both of these turbos with the 67mm GTX compressor would be overkill for that goal. Some people like having a lot of headroom in their turbo selection, allowing for future engine development and more power later down the line. I was just answering the question that was asked

Based on turbo matching simulation work I've done over the years, you should be somewhere between 25 to 30 lb/min of corrected flow on the compressor map, at 6500 rpm on a 2.3L redblock making around 325 bhp. On the 67mm GTX compressor map (same for both GTX2867R and GTX3067R) that puts you right in the peak efficiency island at peak power. This would be optimal for a land speed or drag racing type of vehicle where ultimate peak power is the goal. For a street driven, autox, or road racing vehicle I would probably recommend the GTX2860R for this engine & power level.

Personally I'm going to build my turbo system to be able to handle 400bhp, which is still well within the range of capability for a GTX2860R or 2863R. However the twin-scroll turbine housing option for the GTX3067R is what's making me consider that as my turbo choice. A 3063 could be even better...hmm...maybe I'll make one and try it out!

Honestly an older GT2860R (Disco Potato) or GT2871R is a fine choice as well, but the advantage of the GTX compressor design is much higher pressure ratio capability. At the higher boost necessary to hit 400 bhp the newer turbos will not be overspeeding and will still be fairly efficient, which won't be the case for an older GT28R.
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Old 12-02-2013, 11:58 PM   #12
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Quote:
Originally Posted by Duder View Post
You rang?

This is an interesting question and one that I'd really like to see data for. Unfortunately there aren't any good test results (that I know of) showing a back-to-back comparison of the GTX2867R vs. GTX3067R on the same engine.

It's not exactly an apples to apples comparison since the turbine wheels are of two different designs, and the available turbine housing options are different for the 28 vs. the 30.

In general, irrespective of size, the GT28R turbine wheel aero design (blade and hub geometry) is more efficient than the turbine wheel design used in the GT30R and larger. If you scaled up a GT28R turbine to 60mm, it would outperform the GT30R. However, what's known as the "wheel speed match" is better for the GT3067R vs. the GT2867R. Given the same compressor stage, which is true in this case, going to a larger turbine wheel means the entire turbo will be more efficient.

For the same boost pressure, both turbos in this comparison would be at the same speed. At 2.0 pressure ratio, lets just say the compressor is operating at peak efficiency of 79%, around 33 lb/min and 105,000 rpm. A 60mm (GT30R) turbine wheel will be more efficient at 105krpm than a 53.9mm (GT28R) turbine wheel at the same speed, all else being equal. The complication is, for various reasons that all else is not equal because of the two different turbine wheel aero designs. But let's just say that the GT30R is more efficient at this operating point. The effects of that are:

-Lower exhaust backpressure (less turbine expansion ratio is needed to make the same shaft power)
-Improved VE / flow through cylinder head (because of lower restriction on exhaust side)
-Higher engine power output at the same boost pressure (due to improved VE)

The other thing to consider is the twin-scroll turbine housings that are available for the GT/GTX30R family, but not the 28 (not yet, anyways). A twin-scroll housing with a proper equal length, divided manifold, pairing cylinders 1&4 together and 2&3 together, will take advantage of scavenging and pulse energy to help the turbine spool up more quickly at low engine speeds.


Personally I am just about decided that I'll go with a GTX3067R on my B230FT 8-valve build, with a divided manifold and a new Garrett twin-scroll v-band housing. There is also a new twin-scroll T3 housing if you don't want the v-band option. ATP sells them, along with a weld on inlet adapter for building the manifold from. My guess based on the data I have available to me is that the GTX3067R w/ twin-scroll will outperform the GTX2867R single-scroll - in both spoolup / transient response and also power potential.

I had an Australian guy come up to me at the SEMA show last month and tell me how much he loved the GTX3067R, twin-scroll on his 1.6L Miata. He said that turbo woke the engine up and changed its character completely. He claimed huge power and almost instant spoolup (2500 rpm IIRC) but I didn't see proof so I'll take it with a grain of salt. Regardless, this guy loved it and his engine was much smaller than our redblocks are, but likely flowed similarly given the 16 valve head and higher rev limit.

The main situation that I'd suggest a GTX2867R over a GTX3067R would be upgrading from another GT28, because you can keep the same turbine housing. Or if packaging space for the turbo is extremely tight and a GT30R turbine housing won't fit. If you're stuck on internal wastegating, and won't do twin scroll, then it may be a toss-up in terms of performance between the two. You can't really go wrong either way though.
isn't this a 28 twin scroll?
http://www.atpturbo.com/mm5/merchant...egory_Code=GTH

it's the turbo ive been planning to use
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Old 12-03-2013, 02:09 AM   #13
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All this real turbo talk is giving me sticker shock.
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Old 12-03-2013, 03:29 AM   #14
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isn't this a 28 twin scroll?
http://www.atpturbo.com/mm5/merchant...egory_Code=GTH

it's the turbo ive been planning to use
The link you posted is just for ATP's 0.82 A/R divided turbine housing. It is indeed a twin-scroll housing but was not originally designed for the GT/GTX28R turbine wheel. It's from another application and is machined to fit. I don't have any performance data for that housing since it's modified. But it will fit any GT28R or GTX28R with the 76-trim turbine wheel.
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Old 12-03-2013, 08:52 AM   #15
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Quote:
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The link you posted is just for ATP's 0.82 A/R divided turbine housing. It is indeed a twin-scroll housing but was not originally designed for the GT/GTX28R turbine wheel. It's from another application and is machined to fit. I don't have any performance data for that housing since it's modified. But it will fit any GT28R or GTX28R with the 76-trim turbine wheel.
Yeah I know it's just the housing. Sorry, I was on my phone. It was enough of a task to bold the section I was quoting and find the link

I didn't realize it was something custom. I guess I would've expected some literature on the page with that information.

ATP shows a .82 divided and .78 divided housing for the 3076. Any difference besides the a/r? is one also 'customized'?

http://www.atpturbo.com/mm5/merchant...egory_Code=GTH

http://www.atpturbo.com/mm5/merchant...egory_Code=GTH
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Old 12-03-2013, 10:51 AM   #16
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Come on Toby...you know you want one. All the big boys have them.

You still need to get your @$$ over here and go for a ride don't you...

I've been chatting with the OP for some time about all this and it's good to see some solid info in here, especially from you Chris. I was hoping you'd chime in since, well, you know something about this stuff. lol
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Old 12-03-2013, 01:38 PM   #17
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Well .. there have been written some words of wisdom here !! Deeply impressed !!

Of course there has been a misunderstanding i was talking about 280-300 at the flywheel so about 250 whp BUT i really want to have a turbo that could support mods in the future.

So .. just for anyone that will come up to this decision point again Chris suggested the 3067 if used with a twin scroll housing, which would help spooling like the guy with the Miata. Also suggested an external wastegate per side which would keep things neat.
Now that i don't have a divided manifold so no point using a twin scroll, i should point at the 2867. But as far as i understood due to the lack of information from direct comparison of these two turbos, as he said any would do ok.

Gary has been greatly proud of his 2871, which has been his recommendation from the start, and many poor guys on the road have found out his good choice. The 2867 as far as i can say is an evolution of the 2871, because it can flow better on higher pressures, while at low they are almost the same.

In any case i am not really a fan of external wastegates so i should really stick to the GTX series that does not need it from the start !! Also Gary suggested (since my mani is a T3) to go for a 28 series with T3 ford housing 0.63 A/R, which may be a little help to the turbo compared to the T25 that usually is used. Chris could add some info on this detail sometime as well

My turbo is going to be built like this .. http://s59.photobucket.com/user/nick...023_1.jpg.html

Last edited by aristg; 12-03-2013 at 01:44 PM.. Reason: Forgot the link :)
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Old 12-03-2013, 04:15 PM   #18
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Based on clarification from Aris I went back and looked at the turbo match again. Since it's a 2.1L (I missed that at first), 300 flywheel hp goal, and single-scroll only, I would definitely lean towards a 28 in this case. If he wants the upgraded compressor of the GTX series, there are four to choose from.

1. 60mm, 49 trim "Rally Potato" (likely out of price range due to Motorsports bearing)
2. 60mm, 58 trim GTX2860R
3. 63mm, 56 trim GTX2863R
4. 67mm, 55 trim GTX2867R

Using dyno data from other B21FT engines I came up with an estimated VE curve and BSFC. At 11.5 AFR, sea level, 67F ambient temp, and assuming a 70% effective air/air intercooler, it looks like a GTX2860R would really be best for 300bhp.

This map is fairly "tall and narrow," meaning a limited flow range but high pressure ratio capability. That is perfect for a smaller, low flowing, low revving engine like a B21FT, or a more modern higher revving sub-2.0L race engine for example. As you crank up the boost, your corrected flow rate will increase given a constant engine rpm, so the operating point will move up and to the right on the compressor map. Handily, the GTX2860R at 24 psi & 6000 rpm will be right in the 77% peak efficiency island. The operating point at 6000rpm is 2.76 pressure ratio, 30.5 lb/min corrected flowrate. Plenty of room up and to the right for future boostage increases.



http://www.turbobygarrett.com/turbob...uctCd=GTX2860R

http://www.turbobygarrett.com/turbob...s/GTX2860R.JPG

Overlay these same points on a GT2860RS (Disco Potato) and you'll see the advantage of using the GTX in this case - much higher compressor efficiency at the high boost, high rpm operating points.



You can see we are into overspeed here, and compressor efficiency is drastically reduced. Lower comp efficiency --> more power required to drive the compressor --> higher backpressure required by the turbine --> more exhaust restriction / lower VE --> lower engine output at the same boost and rpm.

If you do go with a GTX2860R, be mindful of compressor surge which you can see might occur based on how close the lug line (red curve) gets to the left hand border of the compressor map. Surge won't cause much of an issue with a ball-bearing turbo and if you use a different turbine housing, your spoolup will be slightly different anyhow.

The Ford style T3 housing with ATP's ultimate wastegate should work really well; I know Gary and a few others have used exactly that on their GT2871Rs. The match work above was done with a Garrett T25 0.64 A/R internally wastegated housing, so I would go with the smaller 0.63 A/R from ATP as you mentioned.

Incidentally, below is the predicted engine dyno power & torque for the GTX2860R match, along with intake manifold pressure and exhaust manifold pressure.

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Old 12-03-2013, 05:31 PM   #19
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Yeah I know it's just the housing. Sorry, I was on my phone. It was enough of a task to bold the section I was quoting and find the link

I didn't realize it was something custom. I guess I would've expected some literature on the page with that information.

ATP shows a .82 divided and .78 divided housing for the 3076. Any difference besides the a/r? is one also 'customized'?

http://www.atpturbo.com/mm5/merchant...egory_Code=GTH

http://www.atpturbo.com/mm5/merchant...egory_Code=GTH
If I'm not mistaken, those housings are from the same family, just different A/Rs. They are both originally from a T3-ish (T31?) application and have been machined to fit various ball bearing turbine wheels and the T25 center housing that's shared by all GT25R - GT35R turbos. I'm not saying these housings are good or bad; just that they weren't originally designed for the wheels they are being paired with.
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Old 12-03-2013, 08:11 PM   #20
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So just to understand, if you project the red line on the 2863R, and 2867R would be outside of the map, ie left of the surge line?

And another point to clarify, is it safe to be on the surge line, despite the fact that the bearings are improved etc?

Also for my engine that is "stupid" ie no electronics ECUs etc (and especially no knock sensor) wouldn't it be wise to use greater flow at lower pressure? Right now for you to understand, i am using a 160 head, with the original B21 intake and exhaust manifolds and my turbine is an (unknown for me) Garrett BCC2 if i recall it right A/R 42, which when it hits 16 psi knocking occurs. So my path of thinking was to stay lower than this pressure but increase air flow. Is this thought wrong ?

And another point to ask. I know that the FT worked at lower turbo pressures than the ET, plus i am at the process of changing my head to a ported 531, the intake manifold to B23 (also ported) and a Mitsubishi exhaust manifold (guessed it .. ported as well). So i suppose all of them would mean greater air flow through intake -> greater volume of gases @ turbine side. How would this move the red line on the map?
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Old 12-03-2013, 08:17 PM   #21
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If you're keeping kjet, why not a b21 intake, aren't they the best of the options?
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Old 12-03-2013, 08:54 PM   #22
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The red line is what's known as the lug line and represents where the compressor is operating during a wide open throttle (full load) pull up through the engine's rev range.

In order to increase mass airflow through the engine, you'll need to change far more than just the turbo - so you are on the right track with the 531 head, and ported manifold. MrBill has a good question, have you considered the B21F (naturally aspirated) intake? At any rate, you should keep going on the quest to remove flow restrictions, make sure you are using the largest (least restrictive) intercooler you can find, nice large radius bends in all the intake tubing, 3" exhaust or larger, and so on.

Yes it's always safer in terms of detonation to make more power with flow vs. pressure ratio. But if all you did was change the turbo, that lug line stays pretty much where it is, and the map shifts to the right. And yes, with a GTX286R or 2867R the lug line will also stay approximately in the same place and the map will shift to the right. All three of the GTX28R turbos have surge lines that are pretty close to each other so it may not be too bad in reality. Also the design of your intake system greatly affects surge performance - in a nutshell: less restriction gives you more surge margin.

With a journal bearing turbo, running off the left side of the map into surge can cause issues with intense thrust bearing wear. The rapid pressure oscillations cause the whole rotating group of the turbo to plunge in and out along the axis of the shaft. With a Garrett ball bearing all the thrust load is taken up within the bearing cartridge since it's an angular contact design (like a wheel bearing) so the main thing to watch out for is blade failure on the compressor wheel from the flow oscillations. It's not "safe" to run in surge per se, but these turbos can tolerate it up to a point.
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Old 12-04-2013, 02:24 AM   #23
aristg
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In order to keep the b21 intake, i have to drill injector holes on the 531, which i really don't want to do. The B21 intake does not have injector holes on it, neither the 531 head . So .. since the b23 intake is better tuned and more free flowing, while has spots for injectors .. it is chosen
Also has different position of injectors which helps atomization of fuel.
I am not sure though why you mention B21F NA version, what difference it has from the B21ET or B23 intake.

Ok, i understood all you said, but the question is (theoretically - i am keeping your word anyway) why the 2863 and 2867 are also not a good choice since the maps are fatter (ok the map moves right) ? Of course not by changing the turbo only but the whole "top" system (intake, head, exhaust, manifold) as i described earlier.
I am still not sure why we choose pressure over flow, since all this stuff is changed. Maybe you mean that whatever i do this setup will never be so good flowing to support bigger flow, and the only solution is to up my displacement in order to have more exhaust gases?
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Old 12-04-2013, 11:00 AM   #24
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As far as the intake manifolds, the B21F manifold is an equal length, longer runner setup than the B23/B230 intake. Still no injector ports though.

The B23/230 intake was the big thing a few years back, before the B21 intake was the next big thing. ;)
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Old 12-04-2013, 01:39 PM   #25
Duder
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Quote:
Originally Posted by aristg View Post
the question is (theoretically - i am keeping your word anyway) why the 2863 and 2867 are also not a good choice since the maps are fatter (ok the map moves right) ? Of course not by changing the turbo only but the whole "top" system (intake, head, exhaust, manifold) as i described earlier.
For your power goals with the B21FT, the GTX2860R has more than enough extra capacity to keep up with breathing improvements you make to the engine in the future. It doesn't really matter how fat the map is if you aren't using all of it.

Quote:
Originally Posted by aristg View Post
I am still not sure why we choose pressure over flow, since all this stuff is changed. Maybe you mean that whatever i do this setup will never be so good flowing to support bigger flow, and the only solution is to up my displacement in order to have more exhaust gases?
The choice is made by the builder (you in this case)...whether you want a smaller displacement, more "peaky," higher boost engine, or a larger, torquier and lower boost engine at the same power level. The torque curves will have a very different shape in the mid range, and the choice just depends on your preference and how the vehicle will be used.

With all of the flow work you're doing and the 531 head I'd guess that your engine will more than make up for the 0.2 liter displacement difference vs a mostly stock B23 or B230.

To clarify, displacement isn't the only solution to increasing flow. In simple terms, airflow through the engine is governed by displacement, volumetric efficiency, and engine speed.

You can increase VE which is what you're doing with the manifolds, porting, and head work. You could keep going and do a ported 16-valve head which would improve VE quite a bit and move the whole lug line curve to the right on the compressor map, without affecting displacement. Increasing engine speed would also add more points to the right side of the map if you could get it to operate efficiently at higher than 6000 rpm, but wouldn't affect the location of the current operating points.

Hopefully this is all clear - my recommendation with your current stated setup and goals is the GTX2860R.
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