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Miata compressor maps

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Old 11-07-2006, 08:38 AM
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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?
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Old 11-07-2006, 09:18 AM
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my T04B-S didn't spool untill 3k with the same turbine. My S60 starts to spools around 1.5k-2k
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Old 11-07-2006, 09:31 AM
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when you guys say spool- are we talking the very first sign of boost?
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Old 11-07-2006, 09:41 AM
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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.
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Old 11-07-2006, 09:48 AM
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right my small 16g spools by 1900 i always thought it was boost onset=spool are braineack and i wrong?
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Old 11-07-2006, 09:54 AM
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Originally Posted by beerslurpy
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.
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
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Old 11-07-2006, 10:41 AM
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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... I paid like 120 shipped for it, its practically all new parts and I never bothered to swap it onto my t3 .60/.63.
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Old 11-07-2006, 10:51 AM
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TO4B-S vs. T3 50 trim







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Old 11-07-2006, 01:09 PM
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Originally Posted by beerslurpy
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 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.
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Old 11-07-2006, 04:38 PM
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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.
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Old 11-07-2006, 05:38 PM
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Originally Posted by beerslurpy
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.
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Old 11-07-2006, 06:10 PM
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Great discussion, guys!

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....
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Old 11-07-2006, 06:15 PM
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Originally Posted by kyle242gt
Great discussion, guys!

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.
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Old 11-07-2006, 07:10 PM
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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!"
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Old 11-07-2006, 07:14 PM
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Old 11-07-2006, 08:15 PM
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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.
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Old 11-08-2006, 07:03 AM
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braineack,
That graph doesn't tell much. Boost? A/F? Same car, same day? Similar cars? Different mods? Engine management?

Frank
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Old 11-08-2006, 08:32 AM
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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.
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Old 11-08-2006, 08:38 AM
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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
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Old 11-08-2006, 08:49 AM
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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

Last edited by brgracer; 11-08-2006 at 09:29 AM.
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