Reduce turbo lag on JDM EJ20TT (EJ20H)?

[Kilroy]

Hello everyone! I've been lurking on the forum and reading for almost two years now, but I finally have a reason to post.

My '94 JDM Legacy Twin Turbo Wagon (123,000 km) will arrive in port in about 2 weeks and I am concerned about the reported lag between the first turbo and second turbo.

Has anyone here owned or currently owns one of these and had success with minimizing the lag? If so, to what lengths did you have to go to do it?

The car will be a daily driver for me, but I do like to give it a push now and then and would like the vehicle to run as smoothly as possible without having to drop a bunch of $$ into it.

[Legacy777]

Welcome to the bbs.

My personal recommendation would be to wait and see how it drives, and go from there before you consider any modifications. This board is primarily US based, so not too many people have driven the twin-turbo setup.

However there are some overseas members who may be able to provide some insight.

[Kilroy]

I'm just looking to be prepared, wasn't planning on doing anything until I had done a test drive. I've posted on a couple of other Subaru boards as well to get as much coverage as possible.

Thanks for the feedback!

[jefferson]

You might want to check out the Australian site Autospeed. They got the twin turbo down there and have articles on it. One in particular had to do with getting rid of the huge hole where the turbos are switching over. It was an ecu upgrade from one of the Aussie companies and it worked very well.

Jeff

[asc_up]

You might want to check out the Australian site Autospeed. They got the twin turbo down there and have articles on it. One in particular had to do with getting rid of the huge hole where the turbos are switching over. It was an ecu upgrade from one of the Aussie companies and it worked very well.

Jeff

I've also heard of this same thing. Just search around for VOD (Valley of Death) Delete on a couple of the Australian boards and I'm sure you'll find something about it.

Although, if you need help with ANYTHING else related to your Legacy, this is DEFINITELY the place to be.

Cheers!

[i_c_the_light]

Best way to reduce lag on a twin snail is to convert to single.

The Subaru sequential setup is just a giant rolling bucket of fail. The only one that has minimal VOD are the later etunes.

[G-unit]

ive had a jdm 94 RS there actually just as quick as a wrx once on the 2nd turbo,better topend than same year wrxs also, just the lag/vod takes a bit of getting used 2,mine ran 10psi and 15psi,

was good fun once over 4500revs

[Kilroy]

Well, I have the car and I hardly noticed the VOD unless I was really watching for it. It's so easy to get to the upper end of the speedo without noticing. I took the wife out for dinner and on the way home I opened it up a little on a lonely stretch of freeway. I asked her how fast she thought we were going, she figured about 100-110 km/h. I pointed at the speedo, we were doing 170 km/h and the car just purred.

Unfortunately, I was driving it to work last week and gave it a push to get around a slow truck before the road narrowed to single lane and when I backed down to 100 km/h I heard a knocking. I think I spun a bearing and I'll be taking it in for a rebuild next week.

[i_c_the_light]

Yep. You've just joined the BEB club.

[Kilroy]

BRB club?

I'm pulling the engine this weekend and still haven't decided exactly what to do. I am leaning towards replacing the SB with a 2.5L SB.

Is it possible to tune with the stock ECU after the swap or will I need an aftermarket ECU for it?

[G-unit]

gutted mate, happens all the time with the GTBs here in nz

[jdmleggy97]

I've got a us swapped bd6 and I threw on a tdo4 as my secondary turbo. Makes more power and vod dosent seem as long