Boosting 2J

[JustenGT8]

I'm trying to fathom the boost control on my Aristo......searched until my fingers bleed and eyeballs dried up and still need another opinion on what's going on?

The car runs an Eboost2 regulating boost to 1bar (FCD so no fuel cut). The sequential system has apparently been fiddled with to run true TT. It does feel that way with bugger all happening boost wise below 4000rpm.

BUT, if i disconnect the Eboost (just running it as a boost gauge) and run the vac reference line straight to the T wastegate line the car starts running more like a seg system? ie boosting from 1500rpm and a very noticeable 2 stage power surge. It's over boosting what the Eboost is set for (Eboost over boost alarm)...but i'm not sure to what boost yet. gets up and goes though

How can this be though. The car can't revert to Seq from TT just with the removal of solenoid control of the vac signal?

All i can think of is that the clueless workshop that installed the Eboost couldn't get it working properly and set the boost curve to feel like TT?

The vac lines have been messed with so it's hard to figure out what exactly is going on as lines don't go where they would as a factory seq set up.

I'll get a boost gauge on the car but with just a straight vac line reference from the inlet to the WGs it should run 11ish psi? Not over 15psi? I know they will overboost with a bigger exhaust (3 inch) so it might just be that and as long as it's under 18psi i'll just leave it like that. Definitely a quicker car without the Eboost

Any ideas?

[natett]

there is a way to change it to an electronic TTC mode.

http://mkiv.com/techarticles/ettc/index.html

pretty much scroll through here and you should find whats going on.

http://mkiv.com/techarticles/index.html

If your not getting boost till 4k then its definately running in TTc mode or parallel twins not seq.

[JustenGT8]

Sorry Nath but read the symptoms more closely...it appears to go from TT to seq with the removal of the Eboost solenoid...all that has changed is how the WG receives it's signal, either true manifold boost or a manifold signal 'bled' by the solenoid? Doesn't make sense unless they have the Eboost setup stupid? In fact, even this doesn't make sense, can't understand how they this can be?

[e30-323ti]

I don't have anything of value to add, other than I've heard a GT35R fixes the problem quite nicely (lol)

and have a chat to this guy: Bmw-E32-2jzgte

[oldcorollas]

stock wastegates? ie, can only reduce pressure to them?

when you say you disconnect the Eboost, but still use it as a boost gauge... the pressure lines are not going to the solenoids? there is no way for pressure to leak from within the unit (however it is still connected)??

earlier boost = wastegate closed = either air being bled off to help spring keep closed, or boost added to assist spring (if you have that kind of wastegate)

late boost = wastegate opening

[JustenGT8]

Yup. This thing has 3 MAP actuated valves...that i can see. The lowest actuator that you can see on the off engine side of the turbos is hooked only to plenum MAP.

A line runs from the positive side of the rear turbo to the EBC and then from the EBC to atm (bleed) and to a T'd line that seems to go to both inboard actuators (the actual turbo wastegates?).

I cleaned up a few more vac lines and spool is better.....i think now i'll play with the Eboost and get more boost and hopefully earlier spool.

without Eboost...so the line to Eboost just goes straight to the T'd to each WG.....i get 25psi!!!! hauls arse but not good for longevity

[Moppitt]

Must resist mods...must resist

It begins (even though this is just getting things working properly)

[wilbo666]

Yup. This thing has 3 MAP actuated valves...that i can see. The lowest actuator that you can see on the off engine side of the turbos is hooked only to plenum MAP.

A line runs from the positive side of the rear turbo to the EBC and then from the EBC to atm (bleed) and to a T'd line that seems to go to both inboard actuators (the actual turbo wastegates?).

I cleaned up a few more vac lines and spool is better.....i think now i'll play with the Eboost and get more boost and hopefully earlier spool.

without Eboost...so the line to Eboost just goes straight to the T'd to each WG.....i get 25psi!!!! hauls arse but not good for longevity

Pretty sure you've seen this

I'm having a bit of trouble working out what your system is setup like currently...inboard actuators?

All the actuators should have VSVs btw... !

Oh and there is only one wastegate for both turbos, its located on the front turbo, the one on the rear turbo is the prespool actuator (It looks really similar to a wastegate)!

It sounds like perhaps the VSV that is inline with the Exhaust Gas Control Valve actuator (EGVC is the valve located in the cast section in the exhaust) is missing? Not sure...

I'd be looking at correcting the setup to factory, making sure it works and then going from there!



Cheers
Wilbo

[JustenGT8]

Cheers Wilbo. What a system...the designer was on speed that day

The w'shop appears to have messed with the brown actuator?...there's a plugged line coming up from there and the Eboost is T'de into a line running down that way. The green actuator is just plugged to a MAP reference and the Eboost runs to the green actuator but it has 2 lines running to it and i haven't tracked down where the 2nd one runs to? Farking lines going every which way

[wilbo666]

Cheers Wilbo. What a system...the designer was on speed that day

The w'shop appears to have messed with the brown actuator?...there's a plugged line coming up from there and the Eboost is T'de into a line running down that way. The green actuator is just plugged to a MAP reference and the Eboost runs to the green actuator but it has 2 lines running to it and i haven't tracked down where the 2nd one runs to? Farking lines going every which way

Oh god, sounds all manner of wrong mate.

I'd suggest
-Reconnect the brown (Exhaust Bypass Valve Actuator) so that it uses the VSV it is meant to (Pink), to be honest I don't think this actuator really has that much of an effect at all... I should do some logging with it on / off to see if it does one day when I have time and motivation...

-The green VSV is the VSV for the wastegate. The wastegate actuator has two ports on it, one set goes off turbo pressure side, and the others goes to the green VSV. When the VSV is engergised it allows the boost pressure to flow back to the intake and makes the wastegate stay closed so the boost is higher. Fail safe (VSV doesn't work) is wastegate spring pressure. Again I'd look at WTF they have done there :S

Cheers
Wilbo

[ra28_miles]

what the hell, these a pressure tank on a 2jz? where the hell is it and why didn't it come on my 2jz!?!

[Draven]

what the hell, these a pressure tank on a 2jz? where the hell is it and why didn't it come on my 2jz!?!

are you assuming it';s the charcoal canister? they look the same, pretty much

[wilbo666]

what the hell, these a pressure tank on a 2jz? where the hell is it and why didn't it come on my 2jz!?!

Yeah there is.

It's tucked up under the intake manifold.

Cheers
Wilbo

[Draven]

since the 2j people in the know are in this thread....

my 2j is missing under boost, time for improving spark. I'm currently tossing up upgraded ignitor (which is supposed to have great benefits) vs 1nz coilpacks vs full MSD system.

Comments?

[beerhead]

LS1 coils are good for 1000hp on a 2J without CDI. I've seen 1NZ/ 1ZZ coils run out of puff at 240hp on a 4AGTE I wired at the 10psi mark, they come off a small 4 cyl, so don't expect too much, they are neat and don't require leads which is a plus. Ran 300hp on 16psi using daewoo lanos GM wasted spark coils through that 4AGTE.