presslab

The 280ZX-T injectors really do not flow much more than the stock EA82T. There is some confusion on the flow rate, is seems that not everyone measures the flow at the same fuel pressure, so without the fuel pressure the cc is meaningless... I'd imagine the 280ZX N/A ones flow the same or possibly less than the stock EA82T. It is possible to "crush" the stock FPR. You will need a fuel pressure gauge. Take a block of wood and cut a notch out of it to clear the vacuum line going into the FPR. Support the FPR in the back with some thin pieces of wood, and put the wood with the notch on the top. I hit the wood on top with a framing hammer about 4 times and bumped up the fuel pressure by 10 PSI. Go slow, if you hit it too much you can't undo it. This is definitely a cheaper option than new injectors. To make the computer happy add a variable resistor to the MAF.

I just installed a short 12" Cherry Bomb glasspack, right after the muffler before the exhaust tip. Perfect - it is still nice when I get on the gas but now it's much quieter in the car while cruising. About the fuel cut - make sure that you do not run lean!! If you up the boost it needs more fuel, and at a certain point the stock system can not keep up. If you up the boost and run lean you will grenade your engine. It is possible to delay the onset of fuel cut with the hot-wire MAF system too! With only the adjustment mod on the MAF, adjust the pot 'lean' so the computer thinks there is less air. The o2 sensor will allow the long-term-fuel-trim to adjust for the MAF error, but the fuel cut will come on at higher air flow.

The "4 plug" ECUs, like mine, use a hot-wire MAF sensor. These models do not have a pressure switch connected to the ECU like the "3 plug" ones do. The ECU will fuel cut when the MAF reading gets to a certain voltage; the fuel cut is a safety for the turbo system, if the wastegate fails closed and the engine flows too much air, the ECU will cut fuel to the engine. With the larger injectors the engine is supplied more fuel for the same MAF reading. By adjusting the MAF and lowering the voltage it can compensate for the larger injectors. The advantage of this is two-fold: The engine can supply more fuel so it does not go lean at high boost levels, and the MAF voltage is lowered so it will fuel cut at a higher boost. http://www.ausubaru.com/forum/showthread.php?t=3784

I have the 280ZXT injectors and modified MAF, that's why I didn't hit fuel cut.

Not very exciting but here is one pic: I cut off, bent, and welded the original hangers. The muffler is a offset input center output. I plan to put a small glasspack on the tailpipe section, as adding it to the center section would further reduce ground clearance. I left a finger-width clearance from the body and propshaft, and the midpipe is higher than the cat and diff but not by much.

Well it's finished, the TD04 is installed using WRX downpipe w/ cats and custom 3" catback exhaust. It's sweet! The topend pulls all the way to redline with no hesitation and it doesn't seem to have any issues with hot weather. I tested upping the boost to 14 PSI and it really had no issues, did not go lean, and had lots of power. Right now it's back to 11 PSI. The boost pressure does not seem as stable as before, something to do with the 3 port stock boost control solenoid. There is a restrictor in there, perhaps I need to modify that. The exhaust has a 3" Thrush muffler, it's like a knockoff flowmaster I guess. It has a nice deep rumble at idle but it's a bit too loud for my taste. I like the tone though, so I plan on adding a glasspack to quiet it down. These are the parts I bought from Jegs.com, about $111 shipped for the exhaust as it is now. The Mustang ball flange fit the WRX downpipe great. 289-17657 MUFFLER WELDED 3.0" O/C 29.99 289-31896 FLANGE MUSTANG TLP 11.99 289-42323 MANDREL U BEND 3" OD 22.99 555-30611 EXH TUBING 3.0"X4'(EA) 16.99 555-30611 EXH TUBING 3.0"X4'(EA) 16.99 I'd post some pics but looks like the photo gallery is not working now.

Yes, just the mods I listed. The car is an '88 GL-10 wagon with rear disc.

The 3-4 slider hub blows up on the manuals.. Mine did. The automatic is probably stronger once you add an external cooler.

Here is a vacuum diagram, kind of hard to read but I think it is all there.

I am also running 11 PSI. The intercooler is a stock WRX one. I need to work on an intercooler shroud to the hood, I also just received a stock WRX "splitter" that I will modify. The intercooler is cold after freeway driving but after being in traffic it does get quite warm. A better intercooler setup would improve slow speed power and sustained power, but I believe the problem I had with the VF7 was that it just wasn't efficient at 11 PSI; basically just blowing hot air.

Received the downpipe/midpipe today, it practially bolted on like it was stock! I added the o2 bung, and I needed to bend a few things to get some clearance. The support bolt at the transaxle front bolted up fine, and so did the hanger at the transaxle rear. The clearance between the propshaft and the end of the midpipe is pretty minimal; it clunks when I go in reverse. I am going to heat the midpipe with a torch and bend it a bit. I still need to do the catback exhaust... I was planning on just hooking to the stock pipe but it's all rusted anyways and pretty small at 1.75". I'm going to do 2.5" and some turbo muffler. I drove it around with just the two cats, it's loud but not super loud. It was 98F today and normally the car is dog slow with that much heat. The VF7 is pretty much just blowing hot air at 11 PSI and the timing gets pulled way back. But with the TD04 it still had decent power. This was my primary motivation for the TD04, to get decent power when it is hot out.

Yeah I haven't seen that on my Subaru heads but on my VW heads I see that all the time! Nothing to worry about. Some people peen the crack with a punch, dunno if that helps. What to look out for on the Subaru heads is a crack up the exhaust port (like mind did when I bought it) if it has been overheated. Coolant will leak out when you turn the car off and give you a smokescreen when you start it up.

Good job!

Man I know the cut wires, someone stole my stereo a couple years back. I just replaced the harness plugs with a universal "ISO" type since I had already rewired to isolate the speakers. The wiring diagram I posted is for the car side colors, I think it's pretty common that the things that plug into the car harness can have different colors. If you look at the connector pinout below the "AM/FM radio" and flip it over, it should match your radio pinout.

I had a look at the service manual. Looks like the MPFI had the "auxiliary air valve" which is just a cold start idle valve. The SPFI has the "air control valve" which sounds like what you have.

I think only the XTs have a IAC. The GL/GL10 have a cold start bypass valve. If the cold start valve is sticky it will just increase idle speed as if the engine were cold... I don't think it would cause surging.

I downloaded this from somewhere a while back... The colors look different but I'd bet the connector pinout is the same, so just match that up to the one in this diagram.

Pics: Welded nut on exhaust manifold Top view Wastegate Front view w/ intercooler temporarily hooked up Side view I started it up without the downpipe, no leaks, almost done.

I believe the ECU controls idle speed by changing the timing a bit. With the green connectors together it disables that, and the timing and the idle speed can be set. Is the timing ok? Idle speed set correctly? o2 sensor voltage toggling? Did you check the TPS adjustment? A smoke machine will find vacuum leaks quickly. CEL but no codes? That's odd.

Is the JDM one with the elbow still a TD04? I am still waiting for my downpipe to arrive, I should get it on Thursday. Hopefully it won't need too much modding; I do expect to add the o2 bung, I bought an anti-foul spark plug spacer (M18x1.5) and cut the end off. I'm also waiting for an oil drain hose, I'll post some more pics soon when I have the turbo bolted down.

The o2 sensor responds in like 0.1 seconds so I don't think that is it. Quite probably the EGR solenoid or a vacuum leak. Maybe the EGR solenoid is broken causing a vacuum leak. You can plug the hose (on the manifold side) to the EGR solenoid and I believe it will disable the EGR system.

I have 280ZXT injectors but I thought about crushing the FPR, should have similar effect and of course it's free. We'll see how it goes when I put my TD04 on, just waiting on the downpipe!

Well all is not lost, I'm sure there is some way to mod it. Take some detailed pics, maybe I can see something?

Here are some pics of the modded TD04: There is about 1/8" clearance from the silicone elbow to the coolant manifold. I have the standard upright intake manifold, not the spider. The silicone elbow is a 2" to 2.25" reducer elbow, the 2" side was shoved onto the turbo inlet. The reducer elbow gained me a bit more clearance to the coolant manifold.

Interesting. The BWD probably has a faster response time than the Bosch. I've not been impressed with Bosch stuff lately. Did your car originally have a heated sensor?