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-   -   TMIC hp/tq gains (

mfarnham 02-17-2010 10:47 AM

TMIC hp/tq gains
What can I get for whp/wtq gains from a TMIC and tune? I plan on installing an EBCS at the same time. Current engine mods are AEM CAI, Cobb DP, Prodrive CBE. Thanks.

newtothegame 02-17-2010 11:03 AM

That really depends on octane using, the weather for the day, and how comfortable your tuner is with what you have, amongst all the other factors. Your fuel pump and injectors will most likely hold you back some. What TMIC you going to run?

mfarnham 02-17-2010 11:14 AM

Probably Perrin. Its the cheapest I can find, while still being a quality brand. But your saying it would be best to do injectors and fuel pump with this also?

And I use 93 octane, if that helps.

newtothegame 02-17-2010 11:21 AM

Lucky that you get to run 93. But if you can either afford it, or get the FP and injectors also you can easily max out the stock turbo with the TMIC, TBE, and a good tune. As far as numbers I cant really be sure.

mfarnham 02-17-2010 11:45 AM

Alright, so its pretty much all or nothing. I am planning on doing it all anyways; I just figured I could do it in sections. Thanks for the info!

I figure with the TMIC, EBCS, FP, and injectors I will be looking at 280-290 whp, with an 18psi map running 93 octane. Does anyone think that sounds reasonable?

newtothegame 02-17-2010 11:50 AM

The numbers of course are kind of dependant on the type of dyno. But they sound reasonable, and Im sure you could easily see 18PSI. I have seen some TD0-4s pushed to 20PSI and make some power, but thats about the max of it. Just remember the stocker is small and will spool extremely quick, but your top end wont be as great. You will still be very happy with that setup tho. Keep us updated.

mfarnham 02-17-2010 11:55 AM

20 psi, huh? I read that 18 was the max of the stock turbo. I'll probably stick to 18psi just so I don't blow anything up. Haha. And I'll definitely keep you guys updated. It's going to be about $3000 for all of this though, so nothing is going to happen for a while sadly...

newtothegame 02-17-2010 11:58 AM

I can understand having to wait, it does kind of suck. But at the end, its well worth it, I know. When you are tuning you can always try for the 19-20PSI mark and if it makes power with proper A/F ratio, with no knock or anything then you are good. But again when all is said and done, you will be happy witih your "new" car. Good luck with it all.

mosc 02-17-2010 04:14 PM

The TD04 can handle 20PSI no problem. The issue is the airflow it generates at that pressure is pretty small. Maybe on the EJ205 you'd want to push it that far but on an EJ255 especially, it wouldn't be kicking out as much air.

Turbos have a curve and their optimal boost levels have a natural rise and fall for different airflows. The max pressure for the turbo is NOT at it's maximum flowrate. Remember PRESSURE=/=POWER, AIR=POWER. Smaller turbos on decent sized motors are not going to be run at max boost, they'll be run closer to max flowrate (less boost).

newtothegame 02-17-2010 08:05 PM

Mosc thanks for better explaining that. I know it, just not as articulate about it.

mfarnham 02-18-2010 07:23 AM

Hmm... I see. So I would make more power running at the best flow-rate, as opposed to running the max boost? Any idea at what psi my turbo would have the best flow-rate?

RcrsWetDream 02-18-2010 08:25 AM

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Look up a compressor efficiency map... That'll show you where the turbo is making the most power, and where it runs out of breath.


That's the map for a TD04-13T, which I believe is what is in the WRX. If you need some explanation on the map and how to read it let me know. Just to explain the pressure ratio real quick, if you're boosting 14.7 psi (atmospheric pressure at sea level) you would have a pressure ratio of 2. If you were boosting half atmospheric pressure, say 7 lbs of boost, your number would be 1.5.

mfarnham 02-18-2010 09:25 AM

Wow... that's a little confusing for me. I might be mistaken but it looks like the highest flow-rate was at a pressure ratio of 2. So does that mean 14.7psi is when the turbo has the best flow-rate?
Does flow-rate make for power than boost? Or is it about finding a happy median between the two?

RcrsWetDream 02-18-2010 10:50 AM

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See the middle "island", that's the sweet spot in efficiency at 76%. You want to keep your turbo in that range so as flow increases, boost can increase as long as the point stays in the middle island. Yes you can go out of the middle a bit, but you want to be in there as much as possible. The most you can theoretically push and be efficient would be about 2.66 pressure ratio and a bit under .15 m3/s (1 m3/s=2,119 cfm). That works out to about 24 psi, which is way more than you want to run.

Basically you can use this chart when you're selecting a turbo for your engine build. For a stock turbo it's merely for reference and there's not a whole lot to get out of it besides knowing when to stop cranking the boost.

mfarnham 02-18-2010 10:59 AM

Alright that makes sense. Thanks for the help. I guess I'll see what works best when the time comes for a tune.

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