Miata compressor maps
 

I had this crappy old jpg that covered the T3 60 map (done by someone else). I didnt think it was terribly useful so I redid it to have less errors and also to show 3 common compressor maps. T3 60, T04B-S, T04E-50.

The maps are to scale via pressure multiplier. I assumed a powerband of 3000 to 8000 rpm which is what the yellow parallelogram traces out. If you like smaller compressors, this jpg isnt for you. This assumes 1.8L engine. Decrease the flow requirements for a 1.6 proportionately.

I did the following PSI:
6 psi- highest you can run without at least FPR
8 psi- highest you can run without going to ECU (IMO)
12 psi- a common pressure for stock bottom end
15 psi- another common pressure
18 psi- why not?

I assumed a 1 to 1.5 psi pressure drop before making the desired psi in the manifold. Maybe this is optimistic, I have no idea.

http://i13.tinypic.com/4i2pl08.jpg

Sweet man, Looks like my 12psi is right in the sweet spot of my 50 trim.
-Michael-

Discussion:

The 60 trim is seems to run out of cfm above 6-7000 rpm beyond 12 psi. I'm not even sure what the compressor map seems to be saying about 18 psi.

The T04B is seems to be in over its head at more than 15 psi with efficiency really not that great in the upper RPMs. It is quite the torque monster from 4000 to 6000 rpms tho. Note the crappy 50 and 60 percent efficiency range in the upper RPMs at 15+ psi. Heat soak for the lose.

The T04E is a complete beast, only just arriving in its peak efficiency area at 18 psi above 6000 rpm. I think it would take some fairly high PSI and headwork to max out this compressor on a miata. Note that the compressor is above 70 percent efficiency the whole time, usually above 74. The T04B maxes out at 73.

By the way, I may have gotten these numbers wrong, but I think remember going over them way back when.

I get way different results. T3 60 or S60 trim should not run off the map.
https://www.miataturbo.net/forums/at...4&d=1162782129
15psi - 10psi - 7psi

try this calculator:
http://www.turbofast.com.au/turbomap.html

Andy Floyd uses another.

1.6:
bore 3.29
stroke 3.07

Hmm, the results I'm getting are similar to what I have for the most part.

2k rpm to 8k rpm, same boost numbers. Note they are a bit lower on boost because they dont assume IC loss at all. I'm a little off in some areas of flow, but mostly good. The boost rows are 6/8/12/15/18.

T04E
http://i13.tinypic.com/2rzvssj.jpg

T360 Trim: Note that my efficiency ratings for the IC on the T3 60 are way generous but you are still way off the charts.
http://i13.tinypic.com/4icuq91.jpg

T04BS: note puke and die above 6k rpms, as seen in my car.
http://i14.tinypic.com/2w6zyuq.jpg

Woops I copied the wrong bore and stroke numbers, but they arent off by much.

I think the disagreement is because you are using the super 60, which is IMO a much harder compressor to find than the regular 60 trim.

Oh yeah and youre using a 1.6L, of course your calculations are going to produce different results. The 60 trim might be tolerant of smaller turbos than the 1.85L.

when you scale it to your actual boost numbers to rpm the numbers ont he map for bhp seem quite low. for example i was making 60 whp an 100+ lbft at 2800 as i was laying into mine on a mustang dyno but the map shows 50 bhp is doable at 100% VE no less. i like squirle performance better http://www.squirrelpf.com/turbocalc/index.php

I have no idea what the correct VE numbers are for those rpms and boost numbers, especially once you factor in exhaust restriction..

Squirrel has a circularity problem in that to pick the correct compressor you need to know the peak hp rpm- but to know the rpm of the peak, you need to know the efficiency map of the compressor you will select- making 350 hp at 6000 rpm requires 20 psi while making it at 7500 only requires 15.

Better to know your likely usage pattern based on what your setup can take and then figure out hp afterwards when you have narrowed it down to a few compressors.

find someone with a solid tec3 map for a miata with boost and copy their VE table :)

here: http://www.y8spec.com/tec3maps/

Well Based on my personal experience the T3 60 trim and S60 on a 1.9L BP ( 1mm overbore ) the car dies off after 6k. This is revving to 7200rpm. On the 1.6L i could run 18psi on the S60 all day and it felt great right until about 7000rpm where it felt like it was beginning to stop making power. On the 1.8 @ 15psi the S60 started to feel weak above 6k and pulling to redline was pretty much useless since it was beginning to lose power...you could feel the compressor getting out of its efficiency. Now keep in mind on the 1.8L the S60 would hit 15psi @ 3300-3500rpm. Thats better boost repsonse than a GT2560R or maybe about the same...and the GT2560R begins to get marginal in about the same area in the rpms that the S60 does. So the fact that it was not building power after 6k is acceptable since its spooling so fast in the first place, and any turbo that hits that soon in the rpms will have a hard time making power all the way to redline.

Oh, forgot to mention VE should be 100% at anything over 4k with boost. Since a turbo increases the engines ability to draw in more the the VE is 100, or thats what I have read...who knows if im right.;)

i suspect you are right if figure at any point where we make 120% of our NA hp we are at 100 or more % effeciency from the numbers i have gotten it seems given a good exhaust and intake cooling 125% VE is not out of the question on the peak.

If the S60 is slightly small for a 1.8L, is there a "next size up" without going to a T04 compressor? How's the GT32 compare to a T04E?

A 46 trim T04E would hit 15 psi by 3000 rpm and hold it till 8000 with no efficiency problems. That plus a .48 stage one turbine side would be quite quick spooling with decent top end at 15 psi. The GT32 has the exact same surge limit and is otherwise identical, only it costs a ton more. IMO, the surge limit is a bigger limitation than the lag on most streetable turbo setups, so the benefit of ball bearing housings is often cancelled out. My biased opinion, obviously.

I am personally not to keen on the T04B compressors anymore. High surge limits with a narrow band of efficiency. Theyre a step down from the T04Es. The only benefit is they flow a bunch better than a T3 60 trim and rarely cost any more.

Oh sorry you meant a bigger T3. Yeah, there is a T3 super 60 if you can find one, but that is as high as the T3 compressor goes and it isnt much better.

I dont see the point of avoiding T04 compressors, it isnt like there is a huge gap between them and the T3 in terms of behavior. The 46 trim is basically a T3 60 trim on roids- similar bottom end (T360 surge is 500 rpm lower than T04E46) but tons more up top.

Man, that is an excellent summation of something I figured out first hand.... just wasn't quite able to put it into words. Had to monkey with my MSnS-E EBC just to keep the turbo from beating itself up. Nice job! :cool:

Similary, I was trying to figure out why the T04B looked like a poor choice - the narrow efficiency is exactly it.

Nice to see that the T04E seems to be the right wheel, getting the trim right just fine tunes it.

Since you maniacs have got me planning a turbo again, it sure seems like the T04E.46/T3.48 would be a sweet hookup; plus, probably inexpensive to put together. ...hmmm... I have a T3 42/48 with a chewed up compressor sitting here. :firedevil Which in turn means you maniacs may bring me back to the Garrett camp as well. Where does the T04E.46 start to spool up? I'd like something that makes ~5psi by 2500, but that might be hard to get.

This has been a great thread, thanks for putting it together. Always nice to see maps plotted.

Uh dude, 5 psi is a nothing amount. My crappy T04B-S makes 5 psi practically off idle. It makes 10 psi around 2500-3000 rpm.

When I'm talking low boost threshold, I mean making a full 15+ psi unless I specify otherwise. The rpms for that will be higher than the RPMs for making lower amounts, due to the shape of the surge limit. See how the 2000 rpm line crosses over the surge limit as you raise the boost? The T04E .46 makes 15 psi at around 3000 rpm- it will probably make 6 psi at 1500. The 50 trim will make 6 psi at just under 2000 rpm.

i dont think we can get any decent sized tubro to 6 psi above ambient by 2500. Heck my turbo only hits 2 psi by 2100 and 6 at 3000. to get something better you would need a teenie turbo and he fairly limited on your performance. i am not that fimiliar with garret turbos though is there something that makes them ulitimatly different from any other?

just a different style compressor wheel.

but overall flow effeciency from wheel to wheel doesnt change even thought you ramp up the speed via a smaller turbine wheel right. or does it shift it all proportional to the size differential of turbo a-b or turbo ab?

my T04B-S didn't spool untill 3k with the same turbine. My S60 starts to spools around 1.5k-2k

when you guys say spool- are we talking the very first sign of boost?

yes, at least I am.

I'll say full boost when I'm talking about full boost. :)

For example, my T3 spools at around 2k and reaches full boost (10psi) by 3.5-4k or so.

right my small 16g spools by 1900 i always thought it was boost onset=spool are braineack and i wrong?

A 46 trim will not hit 15psi by 3000rpm unless you are spraying a ton of nitrous at low rpm and want to break things. You arent gonna make that compressor do 15psi @ 3000rpm, the BP just isnt moving enough air. Even if you cripple that compressor with a stage 1 turbine it wont hit full boost @ 3000rpm:) The GT32 is not otherwise identical either...its a completely different compressor wheel with a lot more technology into it. The GT32 compressor is capable of about the same power, but its not the same as a 46 trim by a long shot. Plus the GT32 I have uses a Gt turbine wheel that is smaller and lighter than a similar stage3 wheel but still flows just as much. I start to spool @ 2500rpm and see 12psi @ 3700rpm. Thats very acceptable in my opinion;)

Does that program have a gt28rs map in it? Can't snag it at work...

ALso... I have a to4b (last i remember, 70-72mm wheel or something) cold side that I'd part with... :p I paid like 120 shipped for it, its practically all new parts and I never bothered to swap it onto my t3 .60/.63.

TO4B-S vs. T3 50 trim

https://www.miataturbo.net/forums/at...3&d=1125710912

http://www.magnaflowonline.com/image...boparts001.jpg
http://www.magnaflowonline.com/image...boparts005.jpg

http://www.magnaflowonline.com/image...boparts003.jpg
http://www.magnaflowonline.com/image...boparts008.jpg

I think you are misunderstanding those graphs a little bit. Yes the compressor is not surging and so its capable of making 6psi @ 1500, its just not going to on a small 4 clyinder engine. You have to realize that our little 1.6L or 1.8L will not make 6psi until at least 2500rpm...why? Thats because the engine cannot ingest 6psi of boost at an rpm as low as 1500, it just doesnt require that kinda airflow at such a low rpm. Now if that 46 trim compressor was on a 302 V8 engine it would more than likely ride the surge line as boost ramps up because of the extra airflow requirements of the larger engine. Even though the compressor map shows the compressor being capable of making 6psi @ 1500 its not gonna happen...thats the limitation of a small 4 cylinder engine at low rpm.

My primitive boat anchor T3/T04B makes about 6 psi at 2000-2500 rpms.

It is not about the miata's "ability to ingest air"- that is entirely a relationship between the surge limit and the miata's headflow.

I dont know what turbine size the GT32 normally comes with, but that compressor on its own should be capable of plenty of boost at low rpms. I suspect your turbine side is a good deal bigger than a T3 48 trim stage 1 turbine.

I will be dealing with a similar problem soon too- the T04E 50 has a lower surge limit than the turbo I am currently using, but the bigger stage 3 turbine is a lot looser. Thus the consensus is that I will make full boost around 4000 rpm rather than 3000-3500.

What I suggested above was that he try a 48 trim stage 1 turbine wheel with a 46 trim T04E- this combines a tight turbine housing with a low surge compressor. It should give quick spool- my current setup pretty much produces a boost curve that EXACTLY follows the surge limit- there is potential for more, but the compressor is forbidding it- the 46 trim would remove this limitation.

I personally used a 50 trim w/ a stage 1 turbine wheel. I wouldnt reccomend it because you are matching a really small turbine wheel with a larger compressor wheel. When you do that you take away efficiency because a smaller turbine wheel will not power a larger compressor as well as a properly sized turbine. My 50 trim w/ stage 1 wheel was making full boost @ 3600, and didnt pull as well as it could have since that small turbine is choking power. if you want boost a low rpm get a Gt2554R or Gt2560R, the t04e series is not the turbo to choose if you want boost at low rpm.

Great discussion, guys! :drama:

Scott has me paranoid of talking compressors, so let me delete a whole bunch of stuff and just ask:

What's a guy to do that wants fast spool, early onset of decent (5psi) boost, and still have headroom to pull to 7000 at 10-15 psi?

That question is what sent me to the land of Mitsu last time....

A T3 S60 .48 turbine w/ stage 1 turbine will have early boost onset around 2000rpm and see full boost somewhere around 3300-3600 rpm and pull all the way to redline on a 1.6L or 1.8L. A Gt2554R will have very early boost onset around 1500-1800 rpm and see full boost around 3000rpm.

Fair enough. I never really cared much about lower rpm boost so I tend to automatically discount any concerns. "It spools at 4000 rpm? Plenty soon!"

What's with the dip/spike at 4K? Cam profile? Boost spike/creep/fade? What turbine on the S60?

The TD04-15G spooled earlier and stronger than the T3, which corresponds to my experience... I know the Mitsus tend to be shunned by the ghetto fab community, but I'm actually thinking TD04-13c, since I could get one for about $30. In practice, they're good to 10psi on a 2.3L.

braineack,
That graph doesn't tell much. Boost? A/F? Same car, same day? Similar cars? Different mods? Engine management?

Frank

Those runs were on the same dyno on the same day. The dip in his torque curve was an electronic boost controller he was beta-testing that was having issues on the dyno.

Look how much faster/earlier/stronger the gt2554 torques up. All were done at 8-9psi. Both the gt2554 and my T3 were having boost controll issues, but you get the idea.

160tq at 3k compared to 100-110tq

Just for the sake of accuracy:

1) all those dyno graphs were done on different days and different dynos, but all were dynojets

2) GT2554R was on a 1.8L and the other two were on 1.6L

3) All turbos were pushing around 8-9psi

4) GT2554R was having fueling issues causing the rich tip in and problems with the transition from open to closed loop causing the dip. AFRs were not ideal as this was an untuned run.

5) T3S60 was having boost control issues causing the dip. AFRs overall good, but a bit rich on the top end.

6) If you look carefully, there is also a little dip in the TD04-15G around the transition into open loop. AFRs well into the rich side < 11 for most of the graph.

7) IIRC GT2554R was using AFPR and FP with stock injectors, T3S60 was using 305cc inj/Vortech/RX-7 AFM, TD04-15G was using Pierburg/1.8 injectors/Begi AFPR

Thanks Tom, I was too lazy to write all that. :gay:

Oh, I'm sorry, I thought those dynos were all on your guys' last dyno day meet-up.

My bad.

No biggie. I guess I should just put all that info on the pic somewhere so it doesn't mislead people....but I'm lazy too. :)

I should do a 15 psi dyno run before I switch over to the 50 trim, but dynos are few and far between in northern florida.

I agree. That would be some nice data to add to the thread.