twin TD04 project

[Gamesy]

i was thinking of doing a twin TD04 project on the svx, my only issue is the maf sensor.

currently i'm running ECUtune 2v4f(iir) setup.
looking into this people use a speed density setup to remove the maf all together,

has anyone done this on an svx?

[Crazy_pilot]

I haven't heard of anyone running speed density on an SVX. Maybe on one of those insane drag builds on a swapped Impreza. The Hydra uses MAP (manifold absolute pressure) sensor, which also does away with the MAF and opens up the HP restriction.

Another option is to have a single air filter, MAF, and then a y-pipe to the turbo inlets if you have the space available (I don't know what layout you're thinking of).

Good luck!

[icingdeath88]

I haven't heard of anyone running speed density on an SVX. Maybe on one of those insane drag builds on a swapped Impreza. The Hydra uses MAP (manifold absolute pressure) sensor, which also does away with the MAF and opens up the HP restriction.

Another option is to have a single air filter, MAF, and then a y-pipe to the turbo inlets if you have the space available (I don't know what layout you're thinking of).

Good luck!

MAP = speed density. Basically, the density part of the equation comes from the pressure/MAP, and the speed part comes from the engine speed and displacement. More advanced explanation here: http://www.megamanual.com/v22manual/mfuel.htm

You're probably thinking of alpha-n.

[Crazy_pilot]

Well how about that... My understanding of speed density was that it's based on intake air temperature and an engine load/airflow table.

Please forgive my ignorance. :o

[icingdeath88]

Well how about that... My understanding of speed density was that it's based on intake air temperature and an engine load/airflow table.

Please forgive my ignorance. :o

Yea that sounds like alpha-n. Basically in alpha-n, the airflow is determined from just the TPS and the engine speed/displacement. In fact, there was an SVX running in alpha-n, dynomatt's rally car, with the megasquirt 2.

[BackWoodsBob]

td04's are cheap as dirt. still want to see where this thread goes.

[Gamesy]

it will be on hold until i'm back in ontario where my svx is parked, i got a td04 for cheap and just needs a rebuild. now i just need to source a second.

my plan will be to mount the turbos in front of each wheel and have a 2in 1out FMIC,

crazy i had thought about y pipe splitter which i may just do.

running the oil and coolant lines will also be a challenge, should be fun on the bun.

i will also be rebuilding my spare eg33 (new rods and pistons)

[icingdeath88]

it will be on hold until i'm back in ontario where my svx is parked, i got a td04 for cheap and just needs a rebuild. now i just need to source a second.

my plan will be to mount the turbos in front of each wheel and have a 2in 1out FMIC,

crazy i had thought about y pipe splitter which i may just do.

running the oil and coolant lines will also be a challenge, should be fun on the bun.

i will also be rebuilding my spare eg33 (new rods and pistons)

That is very similar to what my current build plan is. Either the two turbos in front of the front wheels, or one where the battery was, and one where the abs pump was. I am under the impression that mounting the turbos very low will require a scavenge pump for the oil, and mounting them up above the oil pan will allow them to drain sufficiently by gravity. But mounting them low should make it much easier to leave the amenities like A/C and ABS undisturbed. I think Nate has been kicking around a similar idea as well.

[Tireiron]

ABS is something I wouldn't mind getting rid of completely, but I'm too lazy to take the time to remove it and run new lines. I would rather spend the time replacing the headgaskets and finishing the suspension and brakes heh. I can just pull the ABS fuse and not have to worry about it screwing with any hard heavy braking. But it certainly would leave a TON of room in the front corner where the pump is.

A single turbo would sit very well where either the ABS pump or battery is, duals would work in both spots. That would keep them at exactly the right height to allow drainback with ease as long as the lines are routed correctly with NO uphill sections.

One hard thing will be running the downpipes back past the motor with them upfront. Clearance is very tight past the motor where the PS lines and steering shaft are. You may be able to run them down infront of the motor and then back under the motor either inside or outside of the manifolds. But with both an uppipe and downpipe running in that space between the timingbelt cover and radiator fans that space disappears fast.

Hell, I have 2 td04s sitting around in my basement right now that have been swapped out of wrxs. These things are almost throwaways in the WRX world. I might even have another in a few weeks if my other friend has me swap his out heh.

[Gamesy]

That is very similar to what my current build plan is. Either the two turbos in front of the front wheels, or one where the battery was, and one where the abs pump was. I am under the impression that mounting the turbos very low will require a scavenge pump for the oil, and mounting them up above the oil pan will allow them to drain sufficiently by gravity. But mounting them low should make it much easier to leave the amenities like A/C and ABS undisturbed. I think Nate has been kicking around a similar idea as well.

was there not someone who had 1 turbo in front on one wheel and a small intercooler in front of another?

[icingdeath88]

But with both an uppipe and downpipe running in that space between the timingbelt cover and radiator fans that space disappears fast.

Who says that's the only place to run piping? I was thinking to flip the headers (assuming I stick with the stock headers, which seems likely at this point), so that they point forward, then run each uppipe to the side, under and around the frame, up through a hole cut into the body. Downpipes could be run similarly.

Nate suggested K03s. Thoughts?

[icingdeath88]

was there not someone who had 1 turbo in front on one wheel and a small intercooler in front of another?

If there was someone who did it in an SVX, I don't recall ever coming across it.

[Gamesy]

If there was someone who did it in an SVX, I don't recall ever coming across it.

Should try and find that post, its how I found out the headers could be flipped

[Crazy_pilot]

Who says that's the only place to run piping? I was thinking to flip the headers (assuming I stick with the stock headers, which seems likely at this point), so that they point forward, then run each uppipe to the side, under and around the frame, up through a hole cut into the body. Downpipes could be run similarly.

Nate suggested K03s. Thoughts?

It's definitely doable, I recall seeing a couple swapped Imprezas with that setup. Here's one:

http://i.imgur.com/Xb1TD14.jpg

Although the engineer side of my brain cringes at the thought of plopping a heavy turbo on the end of a bunch of piping without anything else to support it.

[BackWoodsBob]

Found 2 td04's for <150 each. Thinking of running them both under the car. Swap the manifolds side to side, rotate them, bolt the TD's up, run an oil filter sandwich plate which would effectively feed and draw oil from the turbos, T off a coolant line and go to down.

Only problem is the MAF, which, if I'm correct you could just swap straight with an MAP sensor without issue.

[1986nate]

It's definitely doable, I recall seeing a couple swapped Imprezas with that setup. Here's one:


Although the engineer side of my brain cringes at the thought of plopping a heavy turbo on the end of a bunch of piping without anything else to support it.

You can see he has mounts coming off the intake manifold bolts holding it up from a bracket. :)

[BackWoodsBob]

^yep

saw those too.

[jetboy]

Forgive me but would it be practical to remove the airbox and replace it with a cone filter and a turbo?

Also, the windscreen wash fluid reservoir could be scrapped in favour of something smaller crammed in somwhere else.

Without any insight in the matter, I would opt for a setup which did not direct air around and about. I would think that a shorter and straighter flow would be better?

I've just entered a research programme into intercooling.

Wher would you place a MAP?

[BackWoodsBob]

The more apt solution would be to mount the turbo where a stock ej22T turbo goes, but up it to a GT3071R with the 81mm housing and run a FMIC.

I'm just not a fan of all that heat right near sensitive electronics, so I'm making a twin low-mount setup work for me.

[icingdeath88]

Forgive me but would it be practical to remove the airbox and replace it with a cone filter and a turbo?

I'd say a bit more room is needed than that. The most compact setup I've seen is tapani's, which places the turbo just behind the intake manifold, on the right side. Also, routing the exhaust piping to the turbo may not be too easy there, and you might end up with the uppipe coming uncomfortable close to the steering rack, or other heat-sensitive stuff.

Also, the windscreen wash fluid reservoir could be scrapped in favour of something smaller crammed in somwhere else.

Yea, the more room the better. For my build, I'll be relocating/removing:
airbox
ABS pump (ABS delete)
windshield washer reservoir (diverted the pump for the rear tank to the front sprayers)
charcoal canister
battery (moved to trunk)
horns (hella horns in front of radiator)
fuse box will be either turned sideways, or possibly moved into the fender well, still undecided
coolant overflow tank will be swapped for a smaller one in a more convenient spot
All the A/C stuff deleted

I want to have a clean-looking engine bay when all is said and done and I'd like to have as many options available as possible to route the piping.


Without any insight in the matter, I would opt for a setup which did not direct air around and about. I would think that a shorter and straighter flow would be better?

You are right, but it tends to be well worth the trade-off to have the air intercooled. Air-to-water intercoolers can be a good compromise. There are a lot of factors, though, when it comes to positioning - turbo has to be up high in order for the oil to drain by gravity without needing a scavenge pump for example.

I've just entered a research programme into intercooling.

Wher would you place a MAP?

A MAP sensor is typically built into a standalone ECU, such as a Hydra or megasquirt. You just run a vac line from a port on the intake manifold to it.

[Tapani]

No, it's not easy, but compact it is ;).

The steering rack is no problem. Also, the wiring loomes at the top are well protected - both by the heat shield on the turbo and further insulating wrapping. It's all been there for thirteen years now.

See photos.

/T

[icingdeath88]

That really is such a good setup for leaving the creature comforts undisturbed. Remind us all what kind of turbo that is, tapani? And how do you feel about it not being intercooled? Also, where do you have the MAF?

[Tapani]

It is a small T4/T3 hybrid. Boost only 5 PSI. I guess it produces around 280 hp, but the low/mid range feels like it should have from the factory.

You can't really tell is blown by driving it. The turbo spools at 1500 rpm - not very easy with the automatic :-).

But for what it is it performes very well, I think.

It would be nice to measure the compressor discharge temperature and see if an IC would be of benefit.

The MAF is in the original position. The bypass valve is practically the only give a way at a quick glance. See photo.

/T

[jetboy]

It is a small T4/T3 hybrid. Boost only 5 PSI. I guess it produces around 280 hp, but the low/mid range feels like it should have from the factory.

You can't really tell is blown by driving it. The turbo spools at 1500 rpm - not very easy with the automatic :-).

But for what it is it performes very well, I think.

It would be nice to measure the compressor discharge temperature and see if an IC would be of benefit.

The MAF is in the original position. The bypass valve is practically the only give a way at a quick glance. See photo.

/T

Just to understand the basics: 100% of the exhaust is routed through the turbo at all times but it starts spooling at 1500 rpm (when the gas is suffeciently hot / dense / volumous)?

[Tapani]

Just to understand the basics: 100% of the exhaust is routed through the turbo at all times but it starts spooling at 1500 rpm (when the gas is suffeciently hot / dense / volumous)?

Well until the set 5PSI boost level is achieved on the compressor side - then the waste gate opens and let's part of the exhaust flow bypass the turbine side (which drives the compressor) of the turbo.

In my case the waste gate is an integral part of the turbine casting, but it works the same way as so called external ones.

A pneumatic actuator opens a valve and let's part of the exhaust flow pass the turbine inlet.

The turbine and compressor side details must be separately selected for the application at hand to get the target results.

/T

[BackWoodsBob]

I recall in another thread you were hitting fuel cut on 5psi. What's your ecm solution, LAN?

Well until the set 5PSI boost level is achieved on the compressor side - then the waste gate opens and let's part of the exhaust flow bypass the turbine side (which drives the compressor) of the turbo.

In my case the waste gate is an integral part of the turbine casting, but it works the same way as so called external ones.

A pneumatic actuator opens a valve and let's part of the exhaust flow pass the turbine inlet.

The turbine and compressor side details must be separately selected for the application at hand to get the target results.

/T

[Tapani]

With the stock fuel system I hit fuel cut at 5000 rpm and 5 PSI.

I now run Deatchwerks 370cc injectors, stage 2 chip from Mike and the Nissan MAF.

Works pretty well. At WOT (and 5PSI) AFR is 13ish until app 4500-5000 rpm and then app 12.2-12.4 up to shift point @ 6800 rpm.

/T

[BackWoodsBob]

Wow nice, you're running it out to 6800? Do you have cams to let it breath that high?

I don't recall ever seeing a build thread of your car.

[Tapani]

No, but that's where the full throttle shift points are, yes? Maybe my memory is off, I don't do that very often :-).

The turbo was installed in 2000 by the previous owner.

You can follow the JDM drive train + TBDs if you look for the "traction project" in the tranny section. http://www.subaru-svx.net/forum/showthread.php?t=58965&highlight=traction+project&page=2

And some basic info under "Toy" here in turbo..... http://www.subaru-svx.net/forum/showthread.php?t=58585&highlight=toy

Some of the head gasket stuff was here: http://www.subaru-svx.net/forum/showthread.php?t=61822

The engine runs much better now (after the overhaul) than before - and feels stronger by butt dyno :-)

/T

[BackWoodsBob]

Ah, I see. Thanks, I recall you chiming in in the past, and reading a bit about your car, just not a whole dedicated thread.

Thanks for the reading material :)

[BackWoodsBob]

Found 2 td04's for <150 each. Thinking of running them both under the car. Swap the manifolds side to side, rotate them, bolt the TD's up, run an oil filter sandwich plate which would effectively feed and draw oil from the turbos, T off a coolant line and go to down.

Only problem is the MAF, which, if I'm correct you could just swap straight with an MAP sensor without issue.

instead of removing the maf I'm going to use it for tipin enrichment, seal it against boost and clamp it.

[Tireiron]

Most systems run the MAF before the turbo anyway so they don't see boost. The problem is then you would have to Y the intake to both turbos unless you can tune the car and run 2 MAFs, 1 for each turbo inlet. Going to a MAP system with the hydra or megasquirt eliminates that issue and allows an air filter to be stuck at each turbo inlet and be done with it.

[BackWoodsBob]

Most systems run the MAF before the turbo anyway so they don't see boost. The problem is then you would have to Y the intake to both turbos unless you can tune the car and run 2 MAFs, 1 for each turbo inlet. Going to a MAP system with the hydra or megasquirt eliminates that issue and allows an air filter to be stuck at each turbo inlet and be done with it.

Ineed, however, going with a 2:1 intercooler, run the MAF inline with that one tube to the throttle bodies then Y it off right before the throttle inlets. This way you can use the MAF off-boost and use it for tip-in enrichment, then clamp it off as boost rises.

[Gamesy]

back in ontario with my svx so now i will be starting my TT svx project.
ordered the gasket rebuild kit for the spare engine, now i need to source pistons and rods for the build

[Billsy]

so any news on this?

seems everyone with this low mount twin td04 idea fails or gives up.

[Gamesy]

lol since this post my svx water pump went and cracked the housing, got a 2nd svx while i rebuild the laguna, moved across country so i'm a little behind lol

i've talked to a few people and TD04's are still too small even for a TT setup.
so since i need to rebuild my engine, i'm going full build from the ground up might run something like twin GT35R's :D

I will document the build once i get around to having spare funds for it.

[Crazy_pilot]

GT35's?! What kind of power are you shooting for with those?

I've always pictured a pair of GTX28's with V-band housings... Mmmmmm...

[Billsy]

twin 35r's cmon. we can get 700HP out of 1. that and there too huge to fit low mount.
2 td04's will comfortably break 400hp atw.

good to hear you havent given up though.
a 1000hp+ svx would be absolutely epic though if you do fit 35r's :D

[Gamesy]

my goal is to be in the 600 range, twin td04s wont be enough.

i'm gonna get the deck fully closed.

[RallyBob]

A couple of VF39's will certainly meet your needs.

Even a single TD04 pushed to max will make 280 whp on a 2.5 Suby. That's theoretically 560 whp with twins.

[Billsy]

my choice would be twin vf34 if aiming for 600ish. or 2 GT2860's wit hth e .6 rear housing or similar. though the garretts have a much bigger housing to fit in underneath.