First up, the dual range gearbox. This is not strong enough for the turbo charged Foresters so while it may work, it won't last, particularly with the demands of sand driving.

AFAIK, the JDM s/tb has the TD04 out of the factory so without spending a lot of money on something like an MD321 with a billet compressor wheel, the one you have is best. Any other turbos that spin up sooner will have small turbine and compressor wheels so won't go much past 5k.

I have hybrid a TD04-19T that provides full boost at 2.5K and maintains the 1.2BAR I'm mapped to right up to the red line. IIRC, the JDM Forester spools at 3K, is this correct? The final drive on yours is lower than the EDM too so the 3k your engine spools at gives similar results to mine with the higher EDM gearing however, those huge wheels will have raised the ratios somewhat too. How about getting the ECU re-mapped to provide more of what you want? Do you have access to tuners?

Another useful tool to get the boost up immediately is an independent boost control system. I'm using a Gizzmo MS-IBC (plus 3 port solenoid) that has 6 user defined programs for me to play with but I have control over waste gate duty cycle and gain. It's control over the the gain that allows the really fast spool up, or not, as you need but again, a remap would be best, but not essential, to get the best out of this.

 

Hi there

About the engine management, do you know if this ECU will work with s/turbos?

1810U-0031 AEM

 

Do you have a downpipe?

The vf38 and it's brother, the vf37 are twin scroll. They'll give you better response but the boost threshold will still be higher than the td04. You'll also have to swap exhaust manifolds. The only thing you can really do at this point is try to keep all then heat you can manage going to the turbo, or move the turbo closer to your exhaust source.

Have you considered more displacement?

 

I have no idea, what is the ECU from? It's possible same year WRX ECUs will work with your Foz (JDM Forester turbos have the full WRX engine with a slightly different tune) but you would need to check with a mapper as the factory settings will be wrong for your car if it's not from the same model Forester. Why do you want to do the swap? If yours is working, a mapper can make the necessary adjustments when re-mapping. If you change the turbo, you will need to have it re-mapped.

 

Remap is not an option for me. In my city, ther isnt profesional map service, only ******** with low techical skills.

I checked my tdo4 gave me 12 psi at 2400 rpm and up at wot. Maybe it is the best turbo for me isnt?

 

Yes, stick with it. Many of us, including fellas in the more Eastern part of Europe, have to travel some distance for re-mapping. Would you have access to mappers within say, a 150 mile radius? I ask this because, pound for pound, or dollar, a remap on a turbo charged engine is one of the most cost effective tuning options and unless it's done by an incompetent putz, smiles are guaranteed.

Your car was given a "soft and safe" generic map in Japan to cover all territories relative to fuel availability, altitude, driving styles etc. Once your ECU is set for your specific needs, which the mapper can do, the efficiency is greatly increased. However, "chips" are not to be used, they are only for use with fish, dips and burgers etc.

A lot of the guys in the US are using "open source" tuning which is a really good alternative to Ecutek, much less expensive but does require the user to have some skills, a laptop and some knowledge. Open source is constantly being updated by enthusiastic and experienced people whereas licensed applications like Ecutek, tend not to be updated so regularly. Might it be worth looking in to?

 

Vf24 is ideal for automatics due to the low end power

 

That is true but they still don't spool up till 3K, which is fine on the lower ratios of an auto or Group N rally car but not any advantage to the poster. His TD04 spools at 2.5K. The VF will go a little further at the top end but having run one myself, I don't think they are a good add on for the older Foz.