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Old 09-25-2007, 03:12 PM   #1
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Default Obligatory questions about turbos componants.. im such a newb

OK, so im about to fire some questions about turbo setups. I've has s/c's for sometime and know a lot about them.....but to enter the darkside, i need to broaden my horizons and knowledge.

General questions-

a/r.... what exactly DO those numbers mean? I see trim is and trim that... but i dont exactly know what it means.

wastegates- pros and cons to internal and external ones....whats the big deal?



What i want to run-

OK, i DO know good from bad ****... so quality parts do count for me. Im wanting to build a kit utilizing a BEGI cast mani and ideally the BEGI DP. Seems like that would be fine if i go with a turbo like they use in their kits (essentially a no fuel/no intercooled kit). But lets say i decide to change my mind on the turbo itself... to say a T3. Is that custom DP territory?
I hear the GT3271 is a nice little unit, but how does that compare to say... the infamous disco potato (of which very few people know that is was originally meant for a 1.8L miata and where the name came from). Can a T25/28 outperform a T3? Or is it all in the magical a/r numbers?

At the moment, im running a voodoo box and will likely go with some 305cc injectors to give myself some safe headroom for ~10psi on whatever i do. Eventually when the times comes for the MSPNP 99-00, i'll probably go with that, then i'll really have the room to bump up to n/a RX-7 injectors and a bit more boost.Oh, my block is not the original 99... its a rebuilt 96 block with a freshened 99 head So i know i'll be a little safer then if i was running a stock 99 longblock.

Let the discussions and questions begin!
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Old 09-25-2007, 05:19 PM   #2
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Quote:
Originally Posted by DropTopDrifter View Post
OK, so im about to fire some questions about turbo setups. I've has s/c's for sometime and know a lot about them.....but to enter the darkside, i need to broaden my horizons and knowledge.

General questions-

a/r.... what exactly DO those numbers mean? I see trim is and trim that... but i dont exactly know what it means.

wastegates- pros and cons to internal and external ones....whats the big deal?
A/R is something having to do with the ratio of the area of something to the radius of something else. I listen to people who are more intelligent than I am on stuff like that.

Internal wastegates are cheap and easy to control, but for big turbos and big boost they are a little weak and you tend to get boost creep and an overall loss of control of the boost. External gates can be done up to control BIG boost.


Quote:
Originally Posted by DropTopDrifter View Post
What i want to run-

OK, i DO know good from bad ****... so quality parts do count for me. Im wanting to build a kit utilizing a BEGI cast mani and ideally the BEGI DP. Seems like that would be fine if i go with a turbo like they use in their kits (essentially a no fuel/no intercooled kit). But lets say i decide to change my mind on the turbo itself... to say a T3. Is that custom DP territory?
I hear the GT3271 is a nice little unit, but how does that compare to say... the infamous disco potato (of which very few people know that is was originally meant for a 1.8L miata and where the name came from). Can a T25/28 outperform a T3? Or is it all in the magical a/r numbers?

At the moment, im running a voodoo box and will likely go with some 305cc injectors to give myself some safe headroom for ~10psi on whatever i do. Eventually when the times comes for the MSPNP 99-00, i'll probably go with that, then i'll really have the room to bump up to n/a RX-7 injectors and a bit more boost.Oh, my block is not the original 99... its a rebuilt 96 block with a freshened 99 head So i know i'll be a little safer then if i was running a stock 99 longblock.

Let the discussions and questions begin!
Uhhhhh, where to start.

-BEGI makes nice ****. Buying the mani and DP is expensive, but it will give you a SOLID basis to build yourself a nice, reliable, DIY setup and beat on it without worrying about the major components.

The GT3271 is a great unit if you have a standalone, huge injectors, and a desire to make 300rwhp. If you are talking about a kit with no intercooler, 6psi is the MAXIMUM you will want to run, period. (stfu magna) The disco potato is way overkill for that boost; basically anything except a very small T25 is too big for a non-intercooled setup. Get an intercooler in there, get proper-sized injectors (440s or larger), and talk to cjernigan about an MS setup for the '99-00 to get your car running the way it should. That setup will provide the fuel and tuning capabilities to go for 250rwhp easily. Throw in some 550s and a GT3071 and 300rwhp is easy.
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Old 09-25-2007, 05:32 PM   #3
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A/R: the cross-sectional area divided by the radius from the turbo centerline to the centroid of that area

in a nutshell:

a smaller A/R will increase the exhaust gas velocity into the turbine wheel. results: increased turbine power at lower engine speeds, resulting in a quicker boost rise. Reduced the flow capacity of the turbine wheel; adversely affecting peak engine power.

a larger A/R will conversely lower exhaust gas velocity, and delay boost rise. Increased flow capacity; better power at higher engine speeds.

on a miata when we think of large and small we are talking .48A/R and .63A/R


external wastegates work better at high boost levels and can inprove the turbine efficiency; the exhaust gas can be reintroduce further down the exhaust.


BEGi can make a DP for the 3271 with no additional cost to you.

yes a GT2560, GT2871, etc. will outperform a t3 super60.
it has a lot to do with the turbine (flow & spool) and compressor wheel (HP support) and bearings (spool)


a gt2854, gt2860RS, gt2871, gt2876 will all about spool the same. but the 2876 can support up to 480hp where the 2860 (disco) can only support 260hp.
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Old 09-25-2007, 06:32 PM   #4
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So Braineack knows his **** for sure but I may point out 2860RS can make >300, where the 2860 -5 and -10 are a bit more limited. But for efficency the ~200-280 range is ideal for the 2860RS beyond this and you're move out of the efficiency range and should opt for a larger turbo. I think the question that should be asked here is are ya gonna drift, drag, street or some combination? Then the question is where ya want to spool. A big turbo will not spool till ya get into the 4-5K rpm range (w/o a stroker or otherwise built motor) which would be fine for draging but may suck for street/drifting .. A small turbo will spool much lower and give a smoother transition into power and is great for autoX, street etc. Somewhere in between is also a good place to be depends on what you're going to do with it.. I welcome more commentary on this.. Boost lag/late spool may not be all that drift friendly (or who knows this could be just the thing to break your tires loose ;-) ) so some good consideration should go into sizing at this point. Just my .02... I'm curious to see what gets reccomended here.
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Old 09-25-2007, 06:33 PM   #5
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^^^ Thank you! Thats the kinda stuff thats going to stick around for me to remember as i get into all of this.

Oh BTW, i already have a intercooler on my car, as you can see by the pic in my sig. Im pretty sure with the intercooler i already have and the voodoo box i already have... i should be able to run 8-10psi (depending on what turbo i select) with little problem. As for DIYAuto , they are literally right around the corner from me and i have spoken with them about a 99-00 PNP setup when one comes available.

Alrighty, im at work and its past 5:30.... im going home!

Thanks for the input though, looking forward to applying it!
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Old 09-25-2007, 06:36 PM   #6
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Quote:
Originally Posted by Braineack View Post
yes a GT2560, GT2871, etc. will outperform a t3 super60.
T3s are considerably cheaper than ball bearing T2s for the same amount of power capability. Most of us that intend to run relatively high power for minimal coin run T3 equipment primarily for this reason. T3s are also easier to hybrid as a T4 compressor can be tossed onto the front of the unit for very cheap.
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Old 09-25-2007, 07:09 PM   #7
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Mike, next time we end up at a meet or something and there's an opportunity, I'll let you drive my car if you'd like. It'll at least give you an idea of response and what you're looking around at.
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Old 09-25-2007, 10:20 PM   #8
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Quote:
Originally Posted by Braineack View Post
yes a GT2560, GT2871, etc. will outperform a t3 super60.
Slow your roll a bit. The T3 S60 can outperform a GT2560, while the compressor sections are close the edge goes to the T3 S60 (provided you are talking a genuine T3 S60 and not the 60 trim.) Even so, the T3 with the right turbine will out perform a GT2560R.

Finally remember that GT32 and GT30 series turbos will waste an equivalently expensive GT25/28 turbo when it comes to power production. Picking the right turbo is a matter of balance, each turbo has a place where it belongs. If you want a cheap turbo that makes massive power, then the T3/T4 hybrids are where it's at. If you want a fast spooling 220 RWHP turbo then you might go with the GT2554R. If you want a crazy turbo for big power, then a GT35/40 series might be the right turbo like the GT3582R or even GT4088R.

It all depends on budget vs technology. If you are on a beer budget, it's sleeve bearing and old school wheels. If your budget is a bit more robust, ball bearings and new wheels will be on the menu.

FWIW, you want the GT3271, it will outperform just about any T2 housing turbo except the GT3071, but I would still spec the GT3271 because I would want to go with the external wastegate. It won't have the boost creep problems that have appeared from not being able to get enough flow through the internal wastegate. Externally wastegated cars have always seemed to make more power as well, why? I am not 100% sure, I have a few theories.

Mark
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Old 09-26-2007, 12:15 AM   #9
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......says the ghettoccharged one, lol.

But seriously,
im probably seeking the same thing most people are, but maybe not. What i am looking for is a turbo i can start off with and attain a solid 200-210rwhp with on basic fueling and less thne 10psi of boost. Looking to have it spooled up in the 3,000-3,500 rpm range (at least 6-7psi by then), but in the future have the headroom to go near or slightly above the 350rwhp mark (after proper fuel management/injectors). It seems like the GT3271 might be the one for me. Im not MR Technogeek and wanting the newest of new technoligy, but something that gets the job done. Probably going to go with a internal wastegate because i dont think im going to push crazy boost to the point where the internal wont hold.... and to reduce stuff under the hood.
Not to mention the cost of the 3271 seems lower then one of the GT25xxR turbos.

Im pretty set on the BEGI mani and BEGI DP though.

Do i seem to be goign in the right direction here?
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Old 09-26-2007, 12:23 AM   #10
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Compressor wheel trim = inducer squared / exducer squared x 100

Turbine wheel trim = exducer squared / inducer squared x 100
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Old 09-26-2007, 09:54 AM   #11
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the 3271 will not meet your goals for spool. not even close.

take into comparison an '01 with a 2876:



granted the 3271 can support 350rwhp, but i think it may be large for the application. the turbine especially.


You're dead set on the 3276, but I'd highly consider the 3071 instead. it will spool faster, and support your hp goal. and if you find it's too big (probably will), you can downgrade to a 2871 .52 trim(my choice), 2860, 2560, 2554, etc. If you get the 3276 and dont like it, you have no room for error; nothing really smaller that will fit without work and you wouldnt need any larger...so.
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Old 09-26-2007, 09:59 AM   #12
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So the 3071 has the same exhaust flange as the t25/28's? Whereas the 3271 is a t3 flange?
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Old 09-26-2007, 10:02 AM   #13
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Easy get a 16g then when you want 350whp get a evo 3 16g. My small makes 5-6psi by 3K 18 psi by 4800 on my 1.6 i think gotta recheck my logs. 2Scoops is gonna run a 3071 soon if he ever gets his **** together. hopefully there will be updates soon. So far he has a begi mani, with 30 over 1.8 95 head, with oversize valves and AEM EMS.
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Old 09-26-2007, 10:09 AM   #14
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Quote:
Originally Posted by DropTopDrifter View Post
So the 3071 has the same exhaust flange as the t25/28's? Whereas the 3271 is a t3 flange?

yep!



closest i could find to it was a 3076 on a 1.6L.



keep in mind this will have a slightly larger turbine than the 3071, and even smaller than the 3271.



now comparing the two dynos do you see why i reccomend the 2871, if ti can make your hp and spool quicker, why not.
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Old 09-26-2007, 02:14 PM   #15
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Quote:
Originally Posted by DropTopDrifter View Post
So the 3071 has the same exhaust flange as the t25/28's? Whereas the 3271 is a t3 flange?
Yes. As a datapoint my "ghetto" T3/T4 spooled well enough to make over 200 ft/lbs of torque on the dynojet at 4200 RPM and made a peak torque at around 5000 RPM. Using the tighter wheel and A/R housing could drop that almost 1000 RPM. I was using the "stage III" turbine with the .63 A/R exhaust housing, where as another car with a "Stage I" wheel and the .48 A/R housing made over 200 ft/lbs at 3400 rpm and made peak torque at 4200 RPM. Both cars were making 300 RWHP.

Mark

Last edited by Markp; 09-26-2007 at 02:33 PM.
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Old 09-26-2007, 02:40 PM   #16
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mark, dont you have a 1.9L motor though? or was that Andy Floyd ... just figured if you did it should be mentioned since that would make a difference. For what its worth, if you want a quick spooling turbo get a gt25 and some automatic cams. I bet you get a nice powerband from 2500 up to 6500 or so and that would be pretty fun.
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Old 09-26-2007, 03:57 PM   #17
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Originally Posted by Markp View Post
Yes. As a datapoint my "ghetto" T3/T4 spooled well enough to make over 200 ft/lbs of torque on the dynojet at 4200 RPM and made a peak torque at around 5000 RPM. Using the tighter wheel and A/R housing could drop that almost 1000 RPM. I was using the "stage III" turbine with the .63 A/R exhaust housing, where as another car with a "Stage I" wheel and the .48 A/R housing made over 200 ft/lbs at 3400 rpm and made peak torque at 4200 RPM. Both cars were making 300 RWHP.

Mark
OK, now im back to getting confused. Are the a/r's the numbers that make up part of the type of turbo i.e GT"3071" ??


I just remembered i had this a few years ago... something tells me it would have made for a good match with my car :( (one on the left)
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Old 09-26-2007, 04:23 PM   #18
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Ok, how does this one sound...

Garrett T3/T4E, 50trim compressor, Quick Spooling Stage II wheel with T3, 4 Bolt (2.5") discharge 63AR

But dammit, no internal wastegate... so then i'd have to factor in the extra $100 for the external wastegate for the manifold and having a custom DP and buying a wastegate.... argh, this gets confusing.


The GT2560R is stating to look like a good deal though.

Last edited by Doppelgänger; 09-26-2007 at 04:51 PM.
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Old 09-26-2007, 06:29 PM   #19
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2560 is a good deal fast spooling turbo etc. Realy if you wanna stay garret your options on a 3K rpm with 6-7 psi turbo that can make 350 whp are virtualy impossible to get exactly right. Get a t3s60 and live with a 300-310whp ceiling with good spool for cheap or a 2860 for still good spool and a 330 or so whp ceiling, for more money. If you need more help understanding the measurment of turbos this site has helped me a bunch.
http://www.stealth316.com/2-turboguide.htm It is a mitsu biased site but all the same principles apply.
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Old 09-27-2007, 05:53 PM   #20
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OK, you guys do realize im going to be easily influanced here, right? I feel like im playing "what would you build?" game lol. After looking at the suggested turbos and their prices, the T3 super 60 looks to be a good deal. If i ever have the engine management to support proper fuel and can get to 300rwhp.... that'll be more then enough.

Can BEGI modify their DP to accept that turbo?

So far it's looking like
BEGI cast mani w/internal wg for T3 - $389
BEGI seperated DP mild steel - $285
Garrett T3 Super 60 Internal Gated from SpoolinPerformance $645
oil inlet/drain flanges $30


What lines/fitting am i going to need? Where do i tap oil feed from?

SpoolinPerformance has a feed/drain kit for $120, is that a smash or grab deal?
(Turbo feed and drain kit comes with the following PROPER 1/8 BSPT to 1/8 NPT conversion adapter to prevent stripped threads in import blocks. 3 way 1/8 NPT tee 4 ft teflon stainless braided -3AN line -1/8 NPT to -3AN fittings ( Qty 2) -10AN weld fitting -10AN to 1/2 NPT 45 degree fitting -10AN straight hose end -10AN 45 deg. hose end -10AN 14" stainless steel braided hose"
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