Razor2001

Hi guys,

Just to update those that I have been in contact with about my JDM STi-7 (Brett and Pete Croney) mod to a full ScoobySport turbo back exhuast system:

I said that I thought the car felt slower after 4,000 rpms after the mod. Well the feeling was correct. I just did my first blast with a DeltaDash (excellent product so far !) and the maximum boost I could acheive was 10 psi or roughly .68 bar. It would initally hit .68 bar then fall back to about .60 bar held. I even tried the 4th and 5th gear 2,500 rpm cruise then WOT and it would not spike above 10 psig / .68 bar.

This is obviously the result of me needing to play with the size of the restrictor, currently I have a 1.25mm and it is obviously too big !

Good news is with only .68 bar my car had all positive knock correction up to +14 even at 7,000 rpms WOT :-) I guess that will change when I get the boost issues sorted

What 'heading' in deltadash should I be looking under to see if my car is running lean or rich and what are the correct ranges it should be running ?

Injector duty never went above 75%.

I will keep you all informed :-)

PS: My boost guage should be arriving in a week or so Thank goodness as I don't ant to have to hook up th eDD everytime I wantto check boost

Cheers,
Ray

nom

For checking the mixture, you want to look at the O2 sensor reading (think you have more than 1?). 0.89 is typical, but only under boost.

I'm wondering about your boost - seems suspiciously low! What is the wastegate duty cycle doing?

Not sure how you're measuring the data, but just to check it's good to find a flatish straighish bit of road, trundle along in 3rd or 4th at as low an rpm as possible (well, 1,500ish) & then floor it, holding until redline/just before cut/end of road/things are happining a bit quick . 4th can be a tad exciting

RT

FWIW, I've got a 1.1mm restrictor with std exhaust. Usually 1-1.1bar max thru the gears, sometimes 1.2bar in gear 4 hold 3500rpm and then WOT.

I too tried a 1.2mm restrictor and it was waay too big. Could hardly get anything above 0.7bar.

Cheers.

Razor2001

Seeing as you have a JDM STi-7 and also live in similar outside ambient temperatures I think that you have confirmed findings on the restrictor being to big. Thanks for the post RT

Cheers guys !

Ray

Razor2001

Hey Nom, what should the wstegate duty cycle be showing ?

Cheers,
Ray

Razor2001

bttt

Razor2001

bttt

raybotha

Confirms my initial reaction in your first thread . I took a 1mm drill to the standard restrictor , comes out slightly bigger than a 1.1mm as you can imagine . Perfect for me (Sti VII type UK) . Don't be afraid to play , the results can be very interesting and as Deep found out the car is very sensitive to size changes .

The other Ray :-)

Pete Croney

Hi Ray

Its interesting that you are seeing such a low figure. Another user with the same set up as you was in on Saturday, to try a 1.2mm. It spiked to 1.6bar and was immediately reverted to 1.25mm where the spikes dropped to 1.2bar.

It may be that your hot climate will allow the use of a smaller restrictor, so please keep us informed.

Razor2001

I will definately keep you guys informed

Hey Ray, good to know that others are finding differences in sizes

Cheers,
Ray

Deep Singh

Hi Guys,interesting stuff.It was me who decided to try going from 1.25 to 1.2 on Saturday and was getting 1.6 bar in 3rd gear! Car felt very nippy!!

Razor2001

Hey Deep,

I guess 1.6 bar was just the spike and not the held boost correct ?

What boost level are you holding with the 1.2 mm restrictor ?

What length restrictor was put in. I know Pete Croney sent me one approx 1 inch long. I think that length can have an effect as well. So we need to start stating length as well as orfice size.

me: JDM STi-7, full SS turbo back decatt

1.25mm , 1 inch long restrictor, .68 max, .62 bar held

Cheers,
Ray

BRR

Hey Pete, Bret here... (changed logins as I forgot my pwd!)

I'm using a flow control valve now, so I can adjust the effective restrictor diameter at the twist of a dial - works well. I currently have it set to 6.25 turns closed which gives me a peak in normal driving of 1.2, held 1.15 and a worst case spike of 1.3 in "adverse" conditions e.g. floor it in 5th at 3000 rpm.

I got the idea off John (search for thread: "Flow Control Valve Replacing Restrictor")

I also found though, that 1.25 was too big with a fixed restrictor, and 1.1 mm worked pretty well (although not adjustable).

We are running with air temps of around 9-13 degrees C in New Zealand right now, so I'm guessing that this is not the cause of the variation.

(JDM STI7 01 - SS downpipe into 2" decat system, custom built centre section and rear box)

Bret

Razor2001

Hey guys,

Just to update I played with a 1.20 and 1.10 mm restrictor tonight. Oddly enough the boost still stayed at 10 psi ?

Is there anything else that could be causing my car to under boost ?

I am gointg to try the factory .90 mm restrictor tomorrow and see if spikes or not. Right now I just want to see my boost back up to normal levels

Help anyone !

Cheers,
Ray

Razor2001

bttt. help

Thanks,
Ray

Razor2001

Pete C or anyone, thoughts on above boost problems ?

Cheers,
Ray

Razor2001

bttt

raybotha

Ray ,

My car did this without a restrictor ! Makes me think maybe you got the pipes plugged back wrong way or something . Possible ?

Maybe make a trip past a Subaru garage and check with a new one .
Its gotta be a simple solution I believe .

The other Ray

Razor2001

Hi Ray,

Unfortunately we don't have any Subaru delears on the island.

I am very careful when I take things off etc and I know for a fact that I put the restrictor and tubing exactly back the way it is supposed to be. The restrictor is in the tube that is between the turbo connection and the "T" branch off.

Any other ideas anyone ?

Cheers,
Ray

raybotha

Lets get oriented here . If you stand in front of the car (right hand drive) and the pipe with the restrictor is on the opposite side to the solenoid .


Wastegate
|
Fender |
|
Solenoid------------T-Piece------restrictor--Intercooler side

Front of car
Right ?

Ray

raybotha

There's your problem guarenteed . Restrictor should be intercooler side , not solenoid side . Ray , you must have the standard restrictor still there and on the solenoid side too ! I don't recall you mentioning you removed the OEM one .....

Please check now and come back on line , I am intreged to know .

Will be out now for 3 or so hours but will check your respone later with interest . Hope we onto something here .

Later .

Ray

Razor2001

Hey Ray,

I am holding the OEM restrictor in my hand. I removed it when I replaced the one supplied by SS.

All I can say is that I must have put the restrictor in the wrong side if you are correct and it is supposed to go on the intercooler side. Are you 100% sure ???


Cheers,
Ray

Razor2001

Huge thanks Ray for helping me figue out the problem !!!!! Excellent help man

Pete Croney,

It seems I owe you a big apology. The restrcitor you sent appears to be the correct size or close to the correct size after all, I simply had it on the wrong side of the "T". My apologies again.

I am getting 13.5 psi / .93 bar max and .90 bar held in 1st and 2nd gear. I think I may be able to get this up to 14.5 / 1 bar with a slightly smaller restrictor. I am getting max spike at 1.2 bar in 4th gear 3,000 rpm then WOT. Same in 5th gear load test.

I have had no negative knock correction but lots of positive 11 points etc. Waste gate duty % is over 90% at times. Fuel injector duty hits 85% at times. Are these ok ?

Thing I don't like is that in 1st gear I am getting .98 02 volt reading and higher and 2nd gear and onwards I am getting a 02 voltage reading of over 1 - 1.015 at high rpms in WOT....that is too rich, no ?

Oh, I ripped the end (just the tip) of the hose (that contains the restrcitor) when trying to put it back on to the intercooler (from turbo) side (what a nightmare it is fitting that thing without taking the IC off.) Do you think it will continue to rip or will it be ok ?

Cheers again, oh by the way. the car feels AWESOME !!!! well obviously it does, from 10 psi to 14 psi will make a big difference I guess

Thanks again,
Ray

RT

Glad to hear that the problem was simple and you've got it fixed. For sure having the restrictor on the wrong end of the T would result in no boost (better than resulting in 2bar boost eh?).

If you can, post exactly what your boost is doing in each gear: hold, then WOT; and thru the gears.

Cheers!

Razor2001

Will post some more info tomorrow RT.

Thanks again for everyones help :-)

Cheers,
Ray

raybotha

Happy for you Ray . Now put some racing fuel in . My car is a 102 only RON junkie . Apart from the exhaust its the bolloks as the British would say . I found a 1.1mm restrictor best , it gave me closest to standard boost . If I pull off in first gear and nail it I see 1.1bar max which makes a huge difference to acceleration . That is using clutch engagement at low revs and then full throttle . You will see a massive increase in on road performance to another Sti . I gained at least 1 car length per gear , and the advantage is maintained and increased as the motor revs . ie. its torque and power benerficial . Would love to know where Pete C. gets the different size restrictors . I can't even find drill bits that size ! I ripped my hose tip as well and used superglue to melt it back togeather . Dont worry it wont get worse . I am whatching with interest what the feedback on the duty cycle etc is as I had no way of knowing this without the "Tek" . I found the most dangerous area for overboost between 3500 and 4 000rpm's . It would vacilate from .5 to 1 bar then back to .5 bar on light throttle .

looking forward to your feedback Ray . Enjoy

The other Ray

Razor2001

Hi guys,

What is roughly the stock boost levels I should be getting from a JDM STi-7 100% stock ?

I am just trying to play with the restrictor size (probably going to go the Valve adjustment vs. restrictor soon) and want to know what boost levels I should be achieving. I have a full catless turbo back SS xorst

with a 1.25mm restrictor I am getting the following:

1st gear WOT to about 6,500 rpms max: 13.6 psi / .94 bar, held: 13.2 psi / .91 bar

2nd gear WOT to about 6,500 rpms max: 13.5 psi / .93 bar, held:
13.2 psi / .91 bar

3rd gear WOT to about 6,500 rpms max: 14.2 psi / .98 bar, held:
13.7 psi / .94 bar


I am thinking I should be looking more at 16 psi / 1.1 bar held in 1st and 2nd gear and 17 psi / 1.15 bar held in 3rd - 6th gear. Does this sound about right ?

Couple of notes from DeltaDash on the above run:

knock correction was always positive usually above 9

fueling seemed rich with anything above 3,000 rpms showing higher than 1.0 and usually running about 1.015 on the 02 sensor

injector duty percentage was usually at 86% at WOT between 5,000 - 6,500 rpms

engine bay intake temp was about 32 degrees C during this test blast

Did a 4th and 5th gear load test from 2,500 rpms cruising to WOT and max spike in both gears was 17.5 bar / 1.20 bar


I think the above shows that I have room to increase my boost up to about 16 - 17 psi held.

Thoughts / commenst anyone ?

Cheers,
Ray

PS: I love the ScoobySport turbo back catless xorst !!!

PPS: Raybotha: I can only get 98 RON gas down here in Nassau, Bahamas

raybotha

Ray ,

I find the guiding factor the amount of overboost that last only a short wjile on the type UK ie. it will boost to whatever then come back .2 bar and settle there . I also found that high boost at high revs meant a restrictor too big , and the car would not spike at low revs . Remember this is function benefitting acceleration and midrange . I aim for a happy midrange boost response , most sensitive between 3500 and 4000 , punch it there and the car should not overboost by more than .2 as said earlier . Of course this may not mean much your JDM though . I imagine RT will help you there . If I get midrange boost levels right the rest of the rev range is spot on . If the restrictor is too big then it will only start getting boost at high revs but will feel flat .

Ray
Grab the 98 RON

Razor2001

Hi Ray,

Yup, I use the 98 RON everytime. I also add octane booster every couple of fillups but I can only get a booster that adds max 1 RON so nothing significant. I wish we could get NF down here....oh well !

Thanks again for your help !
Ray

Razor2001

Hey Ray,

My restrictor is on the opposite side:


Solenoid ----- ((restrictor)) -----"T branch"----------Intercooler
I
I
I


I am standing here, looking at front of car here ^^


Is this different to yours ? I do have a RHD, JDM STi-7 MY2001. But LHD and RHD is not the issue, my restrictor is inbetween solenoid and T, not intercooler and T ? No ? I thought the solenoid is what needed the correct air flow to it ? why would the intercooler need the restrictor changing air to it ?

Cheers,
Ray


[Edited by Razor2001 - 9/10/2002 5:16:56 PM]