:::RHMT::: Real Home Made Turbo
General Category => Forced Induction => Topic started by: reddevil on August 16, 2009, 04:05:23 AM
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Yeah, so I am rocking the infamous T3/T4, about 340whp @ 5500-6000 rpm. Only issue is that it doesnt hit boost till 4500 rpm, and I have a 6500 redline. AND..... Boost completely falls off in 1st 2nd, almost 3rd when shifting....
Any ideas?
Best so far of 13.3 @ 104.
And while this may be stupid, the slow spoolup with big turbos is gerenally due to the larger exhaust housing correct?
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bigger DP..? more free flowing..maybe a cutout or something
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sounds like your heads flow about as well as piss flows through my dick while i have morning wood.
even a d series makes boost on those before 4500.
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Its on a Subaru for what its worth
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n2o
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n2o
Has not been discounted.... However, this is the daily family wagon, so I need to keep it where I can carry 1 wife, 2kids, a bike or two and a dog.
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Put the correct sized T3 turbo for your power goal. The T4 compressor you have takes a ton of power to spool, and it's too big for your power anyways.
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build up the inside of the turbine housing with jb weld, smaller volume=higher gas velocities=win, im drunk
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free up your exhaust sys.
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get a different car
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Buy a real turbo and chuck the cdm trash.
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Do a boost leak test. It's possible to have small leaks and still be able to hold full boost just fine.
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Yeah, so I am rocking the infamous T3/T4, about 340whp @ 5500-6000 rpm. Only issue is that it doesnt hit boost till 4500 rpm, and I have a 6500 redline. AND..... Boost completely falls off in 1st 2nd, almost 3rd when shifting....
Any ideas?
Best so far of 13.3 @ 104.
And while this may be stupid, the slow spoolup with big turbos is gerenally due to the larger exhaust housing correct?
Any more information on the turbo? How does the pre-turbo piping look?
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subaru's suck shit for quick spool up. Try wrapping your manifold and uppipe. What set up is on this car now?
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What set up is on this car now?
This is the build..
http://www.realhomemadeturbo.com/forum/index.php?topic=2171.0 (http://www.realhomemadeturbo.com/forum/index.php?topic=2171.0)
Running 22ish psi, so over 4500rpm is screams.
And I don't care how much my welding looks, there are no leaks and the inside of the piping is clean....
Up and downpipe are wrapped.
I may have one more boost leak, my throttle body butterfly valve shaft? But I havent had time to change that out....But it is a minor leak (although, minor can be BIG).....
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Get a SPA .63ar divided T3 housing, then make up a quick-spool valve so it's .32ar for spoolup. Or make a better style that works with a divided uppipe, halving the ar# for spooling and making it fully divided for full boost.
Otherwise get a real garrett CHRA. I recall someone on ohmt having power and spool issues, turned out it was the ebay turbo's thrust bearing taking a major shit.
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run -50* timing
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what size is the up ipe? i can't see it in the build thread. if it is 2.5" that could be why it is slugish.
a smaller up pipe would keep velocity up. then again i don't know the up pipe size.
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put a fuel injector in the manifold, set to dump continually
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1. Pick up a HE351ve for <$150 off eBay.
2. Install with wastegate actuator on vgt arm for variable a/r ratio
3. Profit.
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(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fcarsmedia.ign.com%2Fcars%2Fimage%2Farticle%2F782%2F782784%2Fnos-in-your-belly--20070423022634423.jpg&hash=52c1eba8067d4bf9c09ee9d6d9212de1b275a0f2)
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run -50* timing
agreed
can anti-lag come in Subaru language?
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run -50* timing
agreed
can anti-lag come in Subaru language?
better be ready for the block to become one big non-rotating hunk of metal :mexi:
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put a fuel injector in the manifold, set to dump continually
I love this thread. I think this was my favorite answer so far.
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put a fuel injector in the manifold, set to dump continually
I love this thread. I think this was my favorite answer so far.
Get an injector from a direct-injection motor. It can handle the heat & pressure for a while if you put it very close to the head. And pray.
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Iv always wanted to put a water injection nozzle to spray in subaru turbo headers, Its surpose to turn to steam and decrease spool alot. Why is the limiter at 6500rpm? does it fall off after that? we take our 2.5L out to 7-7300k. I also found that my WRX went alot better when I fucked off the standard ecu, piggy back computer, airflowmeter and map sensor clamp and went with a good tune. 1000 times better. Are you still using the Legacy ecu with a piggy back? The v3-6 wrx ecu and loom is a good upgrade.
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Iv always wanted to put a water injection nozzle to spray in subaru turbo headers, Its surpose to turn to steam and decrease spool alot.
or put it in the mouth of the turbo. wet compression is almost 100% efficient.
another thing you could do is use a throttle plate on the turbo inlet that opens a hair slower than the primary throttle, using the engine's suction to create a negative pressure ratio across the compressor to allow the compressor to help drive the impeller shaft.
BMW and renault did this on their F1 turbo engines.
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Iv always wanted to put a water injection nozzle to spray in subaru turbo headers, Its surpose to turn to steam and decrease spool alot.
or put it in the mouth of the turbo. wet compression is almost 100% efficient.
That wont decrease spool tho, but I agree pre turbo is great.
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I am going to go recirculating BOV and give that a shot.
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you have yet to show how the pre-turbo piping looks? that there will tell alot.
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Well then thats your problem. for the most part.
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Pre-turbo is just an air filter basically on a 5" section of adaptor piping that is straight in.
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i'm talking about the exhaust/manifold side.
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Pretty damn perfect.
I admit my welds are "FUCKING UGLY AS SHIT", but I always grind down the inside. And the main exhaust mani is a production unit, with my custom uppipe which is LEAKPROOF and as straight up as possible.
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what size is the upipe? in this case i'm guessing it's something like 1.75-2" tube?
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(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fwww.themotorreport.com.au%2Fwp-content%2Fuploads%2F2008%2F07%2Fwelded-turbo-fins.jpg&hash=ed78ebdc18d75c1989046718440dcda9daae1d57)
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nicely balanced :-X
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Swap a Dirty D in their ASAP :mexi:
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Build a front entry inlet manifold and loose a few feet of intercooler pipe, you have no A/C anyway.
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Eh,,, Something has to be wrong.
1st gear hits 6psi, 4th hits 20.....
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your timing/fuel will help spool too, if you haven't overlooked it.
This too. I tune for 11.5:1 in full boost, but I run 13:1 at 100kPa tapering to 12:1 by 150kPa, 11.5:1 by 190kPa. I used to have it tuned to straight 11.5:1 as soon as it went into boost, and spool was TERRIBLE. It felt like it just bogged when I floored it. Now it climbs into low boost like it's nothing. Just as smooth as can be, no hesitation.
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Went out for a rive thinking to buy a new MAF connnecion..... ie a FERNCO plumbing coupler. I have split them before, but on he drive down 205 and back, no issues,still slowish spool, but it still honked along...
I DID NOTICE the timing I pulled up top though! 3rd gear pulled lickity split from 65-75, then buh.... (well, slower).
The only good out of all this? Havent popped this motor yet.
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Do you happen to have a Drivers side tail light for a 1990 subaru Legacy?
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Do you happen to have a Drivers side tail light for a 1990 subaru Legacy?
Sedan ior wagon, I think they are diff....
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wagon
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think so. will look.
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Eh,,, Something has to be wrong.
1st gear hits 6psi, 4th hits 20.....
So what wastegate/boost controller setup do you have. if your wastegateis opening to soon, it could be causing slow spool.
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This is the boost controllerI have, the Greddy Trust
[/img]http://www.capa.com.au/pics/turbo_wastegates_trust_tvvc.jpg (http://www.capa.com.au/pics/turbo_wastegates_trust_tvvc.jpg)[/img]
I also have STUFFED the BOV so the spring is TIGHT and that actually does seem to help IMMEDIATE boost, but just the jump to boost from vacumn.
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Just putting a few more ideas out there, Is it a standard up pipe or has a flex joint? check for a leaking up pipe. Also try another air flow meter, they are fragile as. Iv never seen anyone use them as a blow through either?? I just remembered I had similar spool problems on my 95 WRX which turned out to be an afm.
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Standard uppipe, "doesnt" have any leaks, MAF does leak, but veddy veddy small, have bigger leak in the throttle body..... THAT I need to change out, just havent yet.
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Did another boost leak test... :(
Found a new leak (old intake manifold gasket finally blew out in the weak sauce spot I was concerned about and the MAF finally gave up. Fixed the maf leak, but need to buy a new gasket. The throttle body is still leaking at the butterfly shaft area, so need to swap that out as well.....
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Damn that sucks, sounds like everything leaks. What's your intake manifold gasket made of? My mazda every gasket on the motor seems to be MLS. Intake, exhaust, head, WP, throttle body, etc.
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Some success!
swapped throttle bodies, replace split manifold gasket, and now the atmosperic BOV is recirculating! Spool is "quicker", nothing awesome, but better. But the big news is that when shifting when getting on it, instead of 20psi-0-1-2-3-4 back to 20, it goes 20-0-10-11-12-back to 20! Big effing diff! Now I think it running extra rich again due to fixing all my leaks.
Must
Get
Tuned
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And found more leaks.... ::)
My fixed MAF didnt "fix", so I redid the seal with epoxy. If that fails, GDIAF!
And found another leak that was effing silent, had to find it by feel. Two weld holes in the piping under the wagon going into the FMIC. Beaded that fucker up.
Better?
I hope so!
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Success?
Well, welded up two pinhole leaks in the IC piping, epoxied the hell out of the MAF, tightened on t-bolt clamp and added some timing in......
The turbo doesnt spool much faster per rpm.....But..... the rpms get there quicker! ie. it is a hell of a lot more responsive now!
Much more fun to drive, even if I have to keep it above 3000rpm....
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I still vote the answer lies in a 50 shot.
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I still vote the answer lies in a 50 shot.
+1
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I still vote the answer lies in a 50 shot.
Real man push 100+shots :evil:
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I still vote the answer lies in a 50 shot.
Real man push 100+shots :evil:
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Dyno tune tommorrow (friday) @ 11:30 am, as long as the dyno owner doesnt flake out (50/50 chance)
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Dynoed today.
On a Mustang dyno, 21psi netted me 294 whp, 300 torque. I compare this to the 292/298 I put down on a dynojet at 15 psi. At 15 psi on the Mustang I did about 245/250.
Sorry, no dynograph.
I do have a crapload of blowby. But car runs well and doesnt smoke just driving around.
Gonna try to make it to the track 2nite and see what #s I can do there.