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thanks man.
Originally Posted by rb26dett
(Post 283763)
are there some videos for a car starved kiwi stuck in england?
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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 ass? 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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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-ass, 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. |
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 ass....
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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. |
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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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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Originally Posted by 18psi
(Post 285047)
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
Originally Posted by rb26dett
(Post 285060)
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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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.... |
Originally Posted by rb26dett
(Post 285060)
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 :-)
Originally Posted by The_Pipefather
(Post 285109)
well, nasioc must be a smorgasbord of misinformation then. I could have sworn I saw this thread there saying what I did.
.
Originally Posted by karter74
(Post 285114)
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.... |
Originally Posted by The_Pipefather
(Post 285109)
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 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. |
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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Originally Posted by 18psi
(Post 284685)
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 ass....
http://img93.imageshack.us/img93/992/capture1qi9.jpg 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? |
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 http://img93.imageshack.us/img93/4447/graphgf3.png |
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. |
looking awesome, man. glad to see you're at the stage you are!
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Originally Posted by rb26dett
(Post 285248)
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. 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 :o |
Originally Posted by The_Pipefather
(Post 285283)
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? 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:D |
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. |
Originally Posted by 18psi
(Post 286637)
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:D |
Originally Posted by AbeFM
(Post 285755)
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.
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.
Originally Posted by AbeFM
(Post 285755)
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).
Which piping? Charge or exhaust? I am taking boost signal off of the compressor right now. Can you point me to more info about this?
Originally Posted by devin mac
(Post 286617)
looking awesome, man. glad to see you're at the stage you are!
Originally Posted by 18psi
(Post 286637)
Also the dropoff is a bit weird to me. At the low boost level you are pushing, it shouldnt be dropping off that low.
Originally Posted by rb26dett
(Post 286660)
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.
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.
Originally Posted by rb26dett
(Post 286660)
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.
Appreciate everyone's help in ironing all the bugs out. |
http://abefm.smugmug.com/gallery/116...54351231_aiCXV pics, a little explination. But, at low flow, the intercooler doesn't present much restriction. At high flow, there is a restriction in all those bends and the intercooler itself.
Take the signal at the turbo, it's constant boost there, minus a varying number across the IC set up. Take it at the manifold, and the wastegate stays shut even when the piping is at 22 psi, overspinning the turbo, overheating the air. Take it right ahead of the throttle plates, and the manifold will always see the same pressure anytime the turbo is capable of supplying it, and you vary what the motor sees with the throttel. |
Nicely said Abe. I have a partly finished write up if you want. PM me for a link if interested.
Thinking about it again, leakage probably wouldn't do what you have in your logs. It would just push the knee point to the right, whereas creep does exactly what you show. 2.25" for the exhaust can't be much of an issue down low where there is stuff all flow, but it could hurt up top. If it's really bad I guess you could still see some improvement in bottom end spool by fixing it. Fred. |
Well, if you want to stop messing around and find out what's going on - esp since I had the 2.25 ex and when I went to 3 it was night and day... Try this:
Pick a day you hate all your neighbors (a turbo quiets it down some, so it won't be that bad) and break the exhaust at the bottom of the downpipe - either leave the ex hanging there or remove it, but let the gas leak out. Drive around the block (I suggest doing this where it's not crowded, or simply wait till the car is warmed up to make the break. Then you'll know what you're missing. If you really like it, get a dump pipe. More likely, build a 3" exhaust. And just live with the late spool, I did for over a year. |
Originally Posted by The_Pipefather
(Post 287072)
Thanks, wouldn't have been possible without your help. :)
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A 3" exhaust is overkill on even a 500+ hp engine. 2" is good for 150+ 2.25 more than 200 which is probably where he is on a b6t with 8psi. I've gotta ask Abe, did your 2.25 use some bodgy baffled-to-hell mufflers and a LOT of particularly sharp edged crush bends?
I know a guy making 400whp on a 2.5" system from a 2.5 litre v6 on 14psi, you just can't tell me that the size matters that much without backing it up with some context and physics. |
Here in a country where we don't make the rest of the world choke on our polution (ha!) the OEM exhaust has 2.25 diameter, with muffeler, resonator, catalytic converter, etc etc.
Presumably he didn't make a 2.25" system custom, he's referring to the OEM exhaust. I like 2.5", and it's likely what I would have made (2.75 without batting an eye).... But... 3" is cheap. That's a big plus. More to the point, the volume of the muffler you use determines how quiet it is. And I'd read a lot of testing, and they said for the best reduction in noise, a bigger muffler is better. Since I wanted a straight through system, I had to go to 3". Taking out the bends... will be where your gains are. Did I need 3" for performance? No. I went the 3" route because it was the best way to keep from waking up the whole neighborhood when I drive, and from getting eyed by cops, and to have the girlfriend actually WANT to ride in my car when we go somewhere.... |
My mates B6 NA mx5 had an oem 2" on it. it should still be suitable for spool purposes, if not top end, with the exception of the rear muffler, then again, US spec cars could be wildly different to his jap or NZ one.
http://i238.photobucket.com/albums/f...remounted2.jpg |
This is definitely a point for discussion: i have read here about people who went to a 2.5" or a 3" from an OEM exhaust (mine isnt OEM though, its levnubhin's old ebay exhaust, plus I don't have a cat) and noticed improved spool.
This is counter-intuitive because the smaller exhaust shouldn't hurt in the low end. Yet it seems to. Why is this? |
The OEM rear muffler is probably pretty bad, that could easily be why, combined with even more hard core cat converters in some parts of the states it could make a big difference. The exhaust on my mates early car would be fine up to some reasonable power (enough to take it from slow to acceptable) because it is all straight through.
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Originally Posted by The_Pipefather
(Post 287425)
This is definitely a point for discussion: i have read here about people who went to a 2.5" or a 3" from an OEM exhaust
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In some kits, with the 99-00 2 cat cars, there's actually a cat between the motor and the turbo - sapping all that energy!
But more likely, the further along cat is the problem - turbos would on differential pressure, a cat after the turbo ensures that the effective 'barometric' pressure is quite high. In a steady state things aren't that bad, but you need a high force to overcome the rotational inertia of the turbo. I bet a 1.5" STRAIGHT through pipe would be better than a 2.5" pipe or even a 3" (if you could find one) that meets the worlds' strictest noise and pollution laws. And remember, a car that's NA needs a lot more muffler and resonator on it than a turbo one, so an NA exhaust is much more restrictive. Anyway, trumping all this: Go for a ride with the exhaust off. If it doesn't make a difference, we're barking up the wrong tree. :-) |
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