Razor2001

Hi Pete (and any others input is welcome as well ,

As you may be aware I have not got my boost gauge yet but have a 'feeling' that my car is underboosting as low down it feels ok but passed about 4,000 rpms I just don't 'fee;' that pull and redline seems to take forever. Car is definately slower overall.

Oh, by the way I noticed this change after I installed the full turbo back SS system with 1.25mm restrictor. This system is the straight thru one with no silencors etc. The low down feels slightly better but the 'pull' is gone.

After reading 'Jamie Whitfields' J-W racing.com post I am wondering if my car (ECU) has deliberately dialed back boost, timing etc.....here is a copy of the post:


Autospeed.com were the people making these claims, stating that the MY01's ECU doesn't understand what is happening and puts itself into a retarded setting because it thinks the engine is in danger, a kind of creap home mode. Something like that anyway I can't quite remember, for a more detailed explanation goto:

http://www.autospeed.com/A_1054/page1.html

Basically I have never found this to be the case, good gains have been had on all the systems, although a remap certainly brings the mods to their full potential.



^----- After reading that along with the article I am wondering if SS has a dyno of a STI-7 JDM before SS exhaust and then one after installation with my system (full decat SS and 1.25mm restrictor) ?

I guess the next step is to get a boost gauge and start playing with restrictor until boost is back at a desired level; however, I am also curious if the the ECU is retarding timing or boost ?

Any advice welcome.

Big thanks,
Ray

Razor2001

bttt

mutant_matt

Get a Boost gauge and see what it's holding. I am assuming that there are no Subaru dealers on the island and that you are by yourself? They have a computer diagnostic tool called a Select Monitor which can monitor Ignition Timing, Boost, Knock Correction and many other things.

You can also buy the DeltaDash software from www.ecutek.co.uk which can monitor all these things on a laptop. Sounds like this would help you no end.......

Matt.

[Edited by mutant_matt - 8/21/2002 1:57:46 PM]

Razor2001

I agree matt; however, I still want to know if this whole ECU thing may be true. One way to prove it is a dyno on the exact car before mods and after mods, same day, same dyno, same car etc...just curious if SS or anyone else has done this ?

Cheers,
Ray

Razor2001

Hi matt,

you are correct, no dealership, I am all by my lonesome

May look into the ECU thing; however, I am not very good with things like that and it sounds tricky. My best bet is to copy mods of those that have a JDM STi-7 and live in a similar climate annd that are running a reasonable safe car.

Cheers,
Ray

Razor2001

The ECUTEK looks good. Does it come with an explanation as to what all the different readings mean ?

Cheers,
Ray

Mo

Ray,

fit a boost gauge and change the restrictor.

Razor2001

bttt, waiting on pete

mutant_matt

Raz,

There is a fair bit of info about it on the EcuTek website....

Matt

Razor2001

Hey matt,

Thanks again. I have already called a USA company that deals with ECUTEK deltadash to see if they have one for my JDM STi-7 in stock. I think they may only stock the deltadash for the USA version WRX. I am hoping that I can use it on my STi-7 JDM with a download or something

Still looking for answers to my original post Pete or anyone else

Cheers,
Ray

Razor2001

bttt

raybotha

Ray ,
i felt same effect with a restrictor too big ie 1.2mm . You loose the push in the back feeling and the turbo is lazy . Change your restrictor and start at 1mm , thats where I was happy . The standard car boosts .2bar over then settles boost level . If restrictor is too small it will overboost more and then underboost and then settle . You can feel this . Pete is right the restrictor is the only thing you need to change to cure the unstable boost . Put the origional restrictor back if you want to see what I mean . It will go like a racing car . Only problem is boost is too sensitive to small throttle inputs . I found it worse between 3500 and 4500rpm . Dont panic , or spend too solve problem , its a simple fix .
Good luck
Ray

Pete Croney

Hi Ray

The latest ECU is permanently trying to get the most out of the car and does not back anything off to counter improvements that you have made.

What you are feeling is boost building from 2800 to 3200, peaking at 3200 and holding the correct level. Before, it was dead until 3800 then overshooting at 4000 and falling back at 4100. The spike feels nice, but isn't healthy and the surge isn't sustained.

You really do need a boost gauge, so you can see what is going on. A Delta Dash will log all of the functions of your car and Pavlo even wrote a formula to use the output to calculate bhp from the readings. It might need some tweaking for your gear ratios.

There is a rolling road day coming up soon and I'm sure there will be some standard and tweaked 7s there. The only run that I currently know of is Jono's 337bhp. This was with a full system and up pipe. Jono was using a standard restrictor at the time, but this wouldn't affect peak power as it only controls the spikes. And these occur as boost is building, not at the end of the rev range on WOT.

In the mean time, enjoy

Pete Croney

Ray

I just read the autospeed. Interesting that they can't improve top end power with their exhaust.

There have been a few WRXs on the rollers here, with our exhaust. Peak power goes from around 225bhp to 245bhp (turbo back exh) or 260bhp with the up pipe fitted. Torque below 3000 rpm is up to 50lbs more with the full exhaust and a steady 20lbs more from 3000 rpm to the red line.

If the exhaust is fitted to a WRX with a PPP, power goes from 250+bhp to 280+bhp.

JIM THEO

Pete
Could you (or Pavlo) post the formula that "extracts" horsepower from Delta Dash log files?
Thanks
JIM

Pete Croney

Jim

Drop Pavlo a mail.

Razor2001

Thanks Pete and others for responses !

I will update you all when I get a boost gauge fitted. Oh, I will be ordering a deltadash today from a USA based company as I am going over there shortly and can pick it up....can't wait to see all the stats my car is running, ie: knock, exhuast temp, etc etc

Cheers,
Ray

raybotha

Hi Pete ,
I agree with your boost spike theory and max power benefits from the pipe . My experience with a 1.2mm restrictor gave the same symptoms as razors car untill I made my restrictor smaller ie 1mm . Now I live at altitude , think 2000m above sea level , perhaps thats why this size works well for me . I am convinced razor needs to reduce his restictor size to gain from early boost , otherwise it feels like a naturally aspirated car that keeps pulling without the midrange kick .

The other Ray (STI 7)

LoFi

Pete,

are you saying that adding the up pipe to a turbo back system on average takes the output from about 245 to 260bhp? Quite an improvement from a small peice of pipe.

Piers LoFi

Pete Croney

Piers

Yes, several WRX owners have been dyno'd at around 260 with the full system and up pipe.

darkblueturbo

this uppipe sounds good! Forgive the stupidness of this, I'm new, will replacing the uppies affect the emissions at all?

Big Goon

My old WRX PPP full-decat RR @ 271bhp + 264ft/lb, using Scoobysport up/down/center and the original PPP backbox.

PCB's old WRX was 280bhp+ on same day with same spec except backbox I think.

LoFi

darkblueturbo

IIRC the up pipe contains a CAT so it will certainly affect the emissions.

Piers LoFi

WRX-Driver

Pete,
can I use your Up and Downpipe with a WRX MY01 PPP without any problems.
Daniel

Pete Croney

Hi Daniel

Yes, we have done this installation many times and it works very well with 100% reliability. One of our staff cars has this exact set up. It is used "enthusiastically" on the road and on track.

As Big goon says, expect between 270 and 280bhp!!