Subaru sand rail

[BLWN BUX]

Hi Guys,

I am a nube here,
I run a (91) 22T in my 900# sand rail.
I built this ride in 93. I do all my own work.

Even stock, you could imagin, this thing is very fast due to high power to weight ratio. It Would probably run equivlent to a full bodied Subaru with 500-600HP

I have gained a fair knoledge on electronic controlles and performance tuning sinec I originaly built this rail.

I want to gain some performance to the next level.

1993-present
I used the stock ECM and preaty much left all the componets in their original location. I have a "Subi Sports" Ecm Chip, I run a Vortech FMU ( about 70# fuel pressure at 10# of boost)
Run a Profec boost controller usialy about 10#

Now, I have reciently contacted "Outfront Motorsports". They have done a lot of work on sand rail applications here in California.

I spoke with one tech / sales guy, and He said that I would first want to change the ECM so we can tune it easly (I agree).

he also said that we should expect about 220-240 FWHP with all other componets as is (stock-heads, cams, injectors, turbo ect)
All at 7-9 PSI boost?

Now??
If Subaru rates this engine at 160 BHP stock, how do they expect to make 30% incerase in FWHP just off of a tune?

I have done a lot of tuning myself, and it preaty much controlling A/F raitios and ignition short of detonation.

is the Subaru base tune that conservitive?

[green91]

Perhaps he meant crank horsepower? I would imagine there are gains to be had with a tune but im not sure about that much. However i would guess that the stock tune is EXTREMELY conservative since the engine is non-intercooled from the factory to prevent detonation.

[jefferson]

You might want to check out Revtronics stage 1 or 2 chip for our cars.

Jeff

[kimokalihi]

What is FWHP? Four wheel? Front wheel?

[BLWN BUX]

Hi,

FWHP is (Flywheel HP) . I am using this for a unit of mesure against the Factory Subru specification i have of 160BHP which should also be at the crank.

I am preaty much sold on an ECM change. The stock one I use is looking for speed sensor output every 20 minutes or so.The speed sensor is on the Subaru transmission.
I use a VW Type one trans due to the rail style I made.

The lack of speed sensor output causes the ECM to through a code. I have still been using it this way.

A new ECM This will give much faster tuning.

The Unit They use is an "EMS Stinger" This the simplest of ECM's as it only needs Cam, Crank angle, water temp, and TPS inputs.

It eliminates the need for MAF, Knock sensor,and O/2 sensor.
it even has its own MAP sensor in the ECM. You just hook up a vacuum line to the box.

[kimokalihi]

Really? How do you tune a motor without O2, knock and MAF readings? I thought those were pretty crucial.

[Skruyd]

Really? How do you tune a motor without O2, knock and MAF readings? I thought those were pretty crucial.

You can tune a motor on EGT sensors rather than O2 sensors. Knock sensor is only used to let the ecm know if it needs to retard or advance timing. The ecm BLWN BUX is talking about can use the MAF but can be tuned so you don't have to have it. Basically tuned off the MAP sensor.

Correct me if I'm wrong people

[BLWN BUX]

Tuning is done on a wheel dyno with a wide band O/2 sensor as part of dyno data collection.

The O/2 senesor used on the dyno, gives Air fuel ratio readings, that are absolutly critical.
We adjust the "Map" to give us ballanced A/F under load as well as crusing and ideling.

This "tune" is then saved in the ECM. This is simular to "Stage I", and "Stage II" computor chips that are avilable for the stock Subaru ECM.

Those chips are simply "saved maps".
They are not simple though. There is a lot of dyno time and perfect tuning that was compleated befor they made those chips.


The "Stinger" ECM is realy for racing / off road only. You can tune it to be clean runnung, and efficeient but it will not make closed loop adjustment for altitude and barimetric changes.

I would like to know more about EGT's wich seams to be factor on tuning Subaru, and or keeping the motor from melt down.

EGT's are not somthing I have been concerned with on my V-8 projects