ej25/ej20tt hybrid

[shadoxity]

sorry peeps.
now i have the spare time, im trying to design a new sequential set-up, which uses manifold pressure to open the exhaust/intake valves for the secondary turbo, as opposed to the fucking rediculous electronically controlled set-up from factory. This will then allow the use of WRX ecu's, for better tunability and performance.

What are you trying to achieve?

You can change around when/how/where the EGCSV opens up on the B4's.

Having the EGCSV open from low revs they both wont spool up till around 4000rpm.
Why do you want to use a wrx ecu? they are essentially the same other than having a bunch of extra functions for the twin specific stuff.

[telemekas]

Unlike the later DENSO TT ECU there are no "open source"/EcuTEK-tinyrex definitions (XMLs) available for the older JECS TT ECU (some can be EcuTEK)
In this case it is possible to simplify the system using some of the Toyota/Supra sequential system ideas.Coupled with a ZeroSports Sequential controller

[ej25tt]

The wrx ECU can be tuned here in Australia. The parameters that can be changed on the b4 are very limited.

As for the tt setup itself, I am designing it to be completely mechanical. Hopefully eliminating all the horrors that plague the b4.

Basically it's going to be a series of boost controllers, determining when the egcv and icv will open.

[Robbks]

As for the tt setup itself, I am designing it to be completely mechanical. Hopefully eliminating all the horrors that plague the b4.
Basically it's going to be a series of boost controllers, determining when the egcv and icv will open.

this has been done before.
and it doesn't work very well

the issue being that when you get to the right rpm/ boost level and get the secondary to activate you WILL have a drop in boost pressure as exhaust gas is drawn away from the primary.
then your MBC's close again and you get a horrible cycle of switching from single to twin.

then once you've re-designed and fixed this issue you get an issue whereby the car will refuse to drop back to the primary, and you're stuck at low rpm's with the throttle nailed and no boost.

the Subaru system relies on Vacuum and the vacuum tank and it can still operate all systems whenever required because the boost pressure WILL be changing all the time.

If you can come up with a good system, good on you, but it's still going to be a compromised system.

i hope you're using custom intake piping and a fully-custom exhaust header design.
because without it, it's still a highly restricted system

[shadoxity]

The wrx ECU can be tuned here in Australia. The parameters that can be changed on the b4 are very limited.

This is wrong, You can tune all the needed parts of the B4 ECU here in aus, if you have the right stuff and know what you are doing (like me )
You have access to just about all the parameters that you would normally adjust in the WRX ecu's except you also have access to all the parameters that make it change from single to twin...
The way i have tuned mine, you barely feel a dip in power when it switches, you just get a huge pull after both turbos are pumping full!

My car is practically stock, but i have removed the rear muffler and replaced with straight through pipe... ANd i have tuned it well. My B4 is faster than a stock STI and almost keeps up with an 02 sti running 21psi.

MOre power to be had after i have time to modify the exhaust.
I get 9l/100 driving around normally.
These are awesome cars after they are tuned right!

[Billsy]

I drove an auto gtb gen2 the other week. Stock mechanicals, tuned to 183atw. Boost had been woud up a bit though.

Pulse Dyno 183 ATW....?

would like to see the "stock mechanicals" list though.
what ECU?

details and dyno chart

now i have the spare time, im trying to design a new sequential set-up, which uses manifold pressure to open the exhaust/intake valves for the secondary turbo, as opposed to the fucking rediculous electronically controlled set-up from factory. This will then allow the use of WRX ecu's, for better tunability and performance.

Billsy had something like this working kind of but it's extremely tedious to set up and keep working consistently

you need a Vacuum source to pull open the ECV, unless you rip it out and use a wastegate actuator and boost tee.
Then you need a boost tee on the ICV to set it to open slightly later than the ECV because you need it pre-spooled before you open it.

then you need to look at how to get it all to close,
because when you open the secondary ECV you WILL lose boost pressure from the primary.

to dig up an old thread (i searched my name to see how popular i was, haha)

to do that was extremely easy. its just changing one vac line and that leaves the ECU only 1 trigger that activates the ECV actuator.
meaning that it cant get its nickers in a knot and get the combination wrong.
its made my changeover better and quite a few people over on RSLC also.

[Bumpty]

Did this hybrid engine end up making any power?
I'm interested..