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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 07-17-2008, 10:28 AM   #61
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thanks man.

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are there some videos for a car starved kiwi stuck in england?
In due time, sire, in due time.
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Old 07-18-2008, 03:40 AM   #62
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I absolutely am dying to see some numbers from your car, as well as the power curve.......how does it feel? does it haul ***? strong? how is the spool, boost onset, does it hold power all the way to the redline? sorry for so many questions, just answer them when ur bored or something lol
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Old 07-18-2008, 10:16 AM   #63
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numbers will have to wait, its either food or a dyno chart for me, i'm totally broke LOL.

however, i will say that in the present state (untuned, pig rich, retarded timing), the car felt much much stronger than an untuned upgraded greddy (miataspeed1point6's car) at 5 psi.

spool is kick-***, i am in boost by 1500 rpm, and a few outings showed that full boost arrives by 2000-2250 rpm, even with a restrictive exhaust. Of course, the fact that its rich and retarded in boost may have improved the spool a tad.

Hoping to put the wideband and IAT in by today, and get it dialed in by this weekend.
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Old 07-18-2008, 04:58 PM   #64
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does it taper at all up top? wrx's having a much larger engine (the 2.5L's) that thing runs out of breath past 5k rpm and just falls on its ***....
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Old 07-19-2008, 02:18 PM   #65
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from the feel and a look at the boost gage, no it doesnt. I got the wideband and IAT in yesterday, will post some datalogs soon so you can see the behavior for yourself.

one thing you have to consider is this turbo is from a EJ255, ie 2.5L WRX, not the 2.0WRX. I read somewhere that these have a slightly different turbine housing, specially in the wastegate and the scroll entry area.
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Old 07-19-2008, 04:30 PM   #66
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wrong. the ej255 and ej205 td04's are IDENTICAL in every meaning of the word. I know because ive bought/ported/sold shitloads of them and measured every single one. Even as we speak I have 3 laying in my garage: 2 from a 2.0 and 1 from a 2.5
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Old 07-19-2008, 04:49 PM   #67
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wow, a 2.5 16 valve with a td04, subaru sucks more than I thought, at least it means they must come off for upgrades quite often and be cheap to find :-)
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Old 07-19-2008, 07:16 PM   #68
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wrong. the ej255 and ej205 td04's are IDENTICAL in every meaning of the word. I know because ive bought/ported/sold shitloads of them and measured every single one. Even as we speak I have 3 laying in my garage: 2 from a 2.0 and 1 from a 2.5
well, nasioc must be a smorgasbord of misinformation then. I could have sworn I saw this thread there saying what I did.


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wow, a 2.5 16 valve with a td04, subaru sucks more than I thought, at least it means they must come off for upgrades quite often and be cheap to find :-)
actually I think its a pretty wise choice. They place the turbo a long way off from the cylinder heads. Almost like a remote mount. And lose a lot of heat in the tubing. To retain good bottom-end torque their turbine must be really small compared to the compressor, hence a TD04 doesnt do too bad on a Subaru, and consequently, a smaller displacement engine (aka Miata) where its placed close to the cylinder head.
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Old 07-19-2008, 07:30 PM   #69
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For everyone who wants to see what kind of numbers they can expect with this setup, checkout this dyno plot from a 95:

http://forum.miata.net/vb/showthread.php?t=216061

This is what sparked me to do my setup, I just never had a build page....
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Old 07-19-2008, 08:02 PM   #70
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Originally Posted by rb26dett View Post
wow, a 2.5 16 valve with a td04, subaru sucks more than I thought, at least it means they must come off for upgrades quite often and be cheap to find :-)
you are completely forgetting what the subaru was designed for, and that is for rallying. Protuned with exhaust ive seen every other ej255 put down 290-300wtq, with about 240whp. Id say that is not all that bad at all.
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well, nasioc must be a smorgasbord of misinformation then. I could have sworn I saw this thread there saying what I did.
.
Nasioc is big enough for you to have to be REALLY careful who you listen to. There is a wealth of knowledge there, but you ABSOLUTELY HAVE TO know who to gain that knowledge from. id say 70% of the **** posted is complete and utter bullshit, from idiots that run their mouth. once you weed those ***** out, you figure out who the real tuners are and listen to them only.
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Originally Posted by karter74 View Post
For everyone who wants to see what kind of numbers they can expect with this setup, checkout this dyno plot from a 95:

http://forum.miata.net/vb/showthread.php?t=216061

This is what sparked me to do my setup, I just never had a build page....
That is really not bad at all....very nice torque curve, and power while not as high as ill be aiming for (about 240whp) is great. Good job man, that really looks like a very smooth/strong power curve you got there.
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Old 07-20-2008, 05:06 AM   #71
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actually I think its a pretty wise choice. They place the turbo a long way off from the cylinder heads. Almost like a remote mount. And lose a lot of heat in the tubing.
I fully understand that if you want to maintain spool and remote mount you must reduce turbine size. However, that does not mean that it chokes at a higher flow. It still chokes at the same low flow as it would mounted up close and personal and still limits power just the same (not on your setup, but on the oem one).

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To retain good bottom-end torque their turbine must be really small compared to the compressor
That's the thing, it's a compromise for bottom end, the result is a filthy torque curve and flat power curve, quite the opposite of what you want on an ideal engine.

One must try to remember that turbos are to make more power (and torque... but that's not the point) and if you want lots of power/accel/speed, you rev your engine. period. Thus having a massive torque spike at 2k and nothing past 5k when you would be a lot better off pulling to 7k is foot shooting for a performance application. Are 2.5t subarus available outside NA ? I've not heard of or seen them at home at least. A quick search on a jap spec site revealed no ej25t powered cars and only old 1999 2000 legacy wagons with it NA making (chuckle) the same power as my girl friends 1.6 litre toyota.

18psi, last time I checked wrc cars and sti's didn't use either 2.5 litre engines of tdo4 turbos. Instead you'll find the poorly built ej20 and larger vf series and td05 units on them. everyday road cars are rarely designed for rally use, exceptions : evo, sti, 323 gtr, pulsar gtir, and maybe some euro homologation stuff that I'm not familiar with.

final word before apologising for hijacking : if the turbo is correctly (oem) sized for the ej20 then it is too small (always) for the ej25, and perfect (modded) for the b6 :-)

/hijack.
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Old 07-20-2008, 08:11 AM   #72
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To continue the subaru hijack a bit, the japanese STi cars have always been 2.0L turbo, due to homologation reasons (to compete in the WRC, of course.) I do not know exactly the reason behind the US market's 2.5L turbo cars.
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Old 07-20-2008, 01:41 PM   #73
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Quote:
Originally Posted by 18psi View Post
does it taper at all up top? wrx's having a much larger engine (the 2.5L's) that thing runs out of breath past 5k rpm and just falls on its ***....
For sure it looks like I am not dropping off boost at high RPM as evidenced by this log:





As you can see, at a peak RPM of ~6500 and 100% throttle, the peak boost was ~8 psi. Of course, at 12 psi it may or may not taper, I don't know.

Is this boost creep or a poorly set wastegate? I don't see over 5.5 psi anywhere below 5000 rpm @ 100% TP.


As for charge tubing/IC efficiency, I am seeing a 30 deg. delta (MAT - ambient) at peak boost. How does this compare to a good IC/around-the-rad tubing?
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Old 07-21-2008, 07:33 AM   #74
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Here is an example of the spool:


RPM - Boost

1300 - 0.1
1500 - 1.1
1700 - 1.3
2000 - 1.7
2200 - 2.7
2500 - 3.6
2800 - 4.7


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Old 07-21-2008, 02:52 PM   #75
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PF - wow, when I first read your chart, I was AMAZED, figuring your numbers were in atmospheres - 14 psi at 1500 rpm is really very good!

But 4.3 atmospheres seemed a bit extreme. :-) Anyway, if you want more boost early, you can retard the spark. My guess is, looking at your piping, that you WILL see the boost falling off, depending where you take your boost signal (right ahead of the throttle plates is ideal for reasons I won't get into here). There's a certain amount of flow the pipes will handle without significant restriction, 8 psi on a 1.6 is probably below that. At 12 psi I had a couple psi of loss till I got my new set up.

When I was running a "safe" set up, with lots of timing pulled and lots of extra gas, I kept getting way more boost than I wanted - so if you really want more boost, lean in that direction down low - the MS-II (don't know about yours) has, as part of EAE a boost asssist, which tweaks the mixture to get faster spool. Maybe play with those settings.

Lastly, be sure your wastegate rod has a little pre-tension on it. Sometimes, if they are only barely shut, they can blow open slightly, and will leak exhaust even at low boost, slowing spool. 5k seems a bit high... Unless the turbo is really big. All my eclipse buddies don't even expect boost till 6k, but they have "straight line" motors, with turbos sized for cargo carriers. :-)

------------------
Edit: Huh, you know, I wouldn't be too worried about the boost you're seeing. What's your exhaust like? TIll I went to a 3" catless, I never got full boost till ~3800. Now I get it maybe 3k, maybe 2650 uphill in 5th.
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Old 07-23-2008, 12:49 AM   #76
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looking awesome, man. glad to see you're at the stage you are!
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Old 07-23-2008, 01:40 AM   #77
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Quote:
Originally Posted by rb26dett View Post
I fully understand that if you want to maintain spool and remote mount you must reduce turbine size. However, that does not mean that it chokes at a higher flow. It still chokes at the same low flow as it would mounted up close and personal and still limits power just the same (not on your setup, but on the oem one).



That's the thing, it's a compromise for bottom end, the result is a filthy torque curve and flat power curve, quite the opposite of what you want on an ideal engine.

One must try to remember that turbos are to make more power (and torque... but that's not the point) and if you want lots of power/accel/speed, you rev your engine. period. Thus having a massive torque spike at 2k and nothing past 5k when you would be a lot better off pulling to 7k is foot shooting for a performance application. Are 2.5t subarus available outside NA ? I've not heard of or seen them at home at least. A quick search on a jap spec site revealed no ej25t powered cars and only old 1999 2000 legacy wagons with it NA making (chuckle) the same power as my girl friends 1.6 litre toyota.

18psi, last time I checked wrc cars and sti's didn't use either 2.5 litre engines of tdo4 turbos. Instead you'll find the poorly built ej20 and larger vf series and td05 units on them. everyday road cars are rarely designed for rally use, exceptions : evo, sti, 323 gtr, pulsar gtir, and maybe some euro homologation stuff that I'm not familiar with.

final word before apologising for hijacking : if the turbo is correctly (oem) sized for the ej20 then it is too small (always) for the ej25, and perfect (modded) for the b6 :-)

/hijack.
Bro, I dont know where you are getting your information from, but I have been tinkering with subaru's for quite a few years and tune them as a side job, and let me assure you: the car makes phenomenal torque and power, even on the puny td04....the ej25's we are referring to are in the 06+ wrx's, as well as the 04+ sti's....it is a HUUUUUUGE improvement over the 2.0, the japanese using the 2.0's does not mean they are superior, simply it is because the class they run their cars in requires 2.0.......
As far as wrx's, bone stock with a tune (mine, or something similar) it is very common to see 290 WHEEL TORQUE and 240wheel power.......the torque curve starts at about 2500 rpm and starts to fall off after 5500 or so....Stock sure the torque and power is not very good, but even on a stock boost 2.5L wrx, the power/torque is a plenty pretty much everywhere in the power band.....dont get me wrong, I am not trying to change your opinion, but to say that the car is poorly thought out and that they make mediocre power is just ridiculous...I would discuss this for another 2-10 pages, I am a huge subaru geek, but I dont want to thread jack this thread any further...If you disagree, feel free to pm me your thoughts/opinions and we can have a decent conversation, and I will try to show you what I mean.


pipefather, SORRY for the thread jacking bro, I promise ill stop
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Old 07-23-2008, 01:53 AM   #78
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Quote:
Originally Posted by The_Pipefather View Post
For sure it looks like I am not dropping off boost at high RPM as evidenced by this log:



As you can see, at a peak RPM of ~6500 and 100% throttle, the peak boost was ~8 psi. Of course, at 12 psi it may or may not taper, I don't know.

Is this boost creep or a poorly set wastegate? I don't see over 5.5 psi anywhere below 5000 rpm @ 100% TP.


As for charge tubing/IC efficiency, I am seeing a 30 deg. delta (MAT - ambient) at peak boost. How does this compare to a good IC/around-the-rad tubing?
With that plate you have on the downpipe, I couldnt imagine there being any creep bro, that usually happens when your downpipe/exhaust outflows the turbo's hotside.
Also the dropoff is a bit weird to me. At the low boost level you are pushing, it shouldnt be dropping off that low. There is definitely some more research to be done to figure this out, but hey: at least its working right? the hard part is over, now for the tedious part of working out the kinks
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Old 07-23-2008, 03:27 AM   #79
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PF, how high are you planning to rev it to? If you add PW and AFR to your logs it will be more easy to see what torque is doing as the revs climb.

If AFR is constant, and PW is linear in it's increase then you have consistent airflow all the way and consequently consistent torque all the way too. Reality says that at some RPM that PW line will bend off in the downward direction indicating air flow is slowing down. This can/will be cams, manifolds, throttles, plumbing and exhaust dependent just as much as the turbo.

I'm not sure what you are supposed to rev those B6 engines to, but give it a blast and log those two parameters along side to see what's really going on.

For example, my torque seems (by the logs) to start falling away at 6500, but you couldn't tell that by driving it as it's still pulling plenty hard. I rev to 7500.

Abes tips are all good for spool increase :-)

Boost creep is where you get more than you want at higher rpm, what is the gate supposed to give stock? If it's 5.5psi, then yes, that's exactly what it is, if its 8psi, you probably have some leakage or something causing down low to not make target.
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Old 07-23-2008, 02:01 PM   #80
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Quote:
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With that plate you have on the downpipe, I couldnt imagine there being any creep bro, that usually happens when your downpipe/exhaust outflows the turbo's hotside.
Also the dropoff is a bit weird to me. At the low boost level you are pushing, it shouldnt be dropping off that low. There is definitely some more research to be done to figure this out, but hey: at least its working right? the hard part is over, now for the tedious part of working out the kinks
I have my doubts, excepting too little spark advance, that you're getting creep from the pipe... But it IS a possibility as flow rates increase. Again, I guess as someone has more experience with that sort of pipe, but with people like BEGI putting out systems with a whole divorced pipe, at least some people think the flow from the wastegate is important. Imagine making that gap smaller and smaller, until it doesn't flow anything at all. Where is "enough" for you? Depends what boost you want. I've worked on mine quite a bit, and aside from tuning for less boost, I've also just decided to make the motor run at the lowest boost I can acheive. Kinda wimping out. :-)
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