*Sonic*

Just saw this, and wondered if anyone on here has tried it, or even if we have this 'restrictor' in place

http://www.scoobymods.com/forums/sho...&threadid=1564


Steve

Jamesn

Sonic,


This is raved about as the "free boost upgrade" on the 200 SX site.
I have heard that the restrictor is to prevent boost spikes occuring which can damage the engine.

Better to just fit a Dawes - connects between the same two places.


J.

*Sonic*

yep I thought so, I got a dawes in the cupboard, had it on the car, but took it off again temporarily

Might stick it back on, now I got all my gauges & knocklonk working etc

Steve

Turbo_Steve

The restrictor is there to "smooth out" the ECU control of boost.
With a larger restrictor, boost tends to grow quicker, and spike briefly before the ECU gets it under control.

You are unlikely to cause any damage, but you ARE likely to hit fuel cut on cold days at high load.

The Dawes (which goes between the bleed nipple on the turbo, and the actuator, NOT connected to the factory plumbing) is generally a better solution as you retain a degree of control: even if the ECU doesn't.

Changing the restrictor CAN have benefits on a re-mapped engine.

*Sonic*

Thanks Steve

the biggest thing is Dawes 50 quid, new restrictor (bigger) about 60 pence

4wheel

iTrader: (2)

where can you get this bigger restrictor pipe and will it work on my 95 wrx import r u sure it doesnt damage engne in any way

StickyMicky

hmmm i just replaced all them pipes today with nice red silicone ones and i dont think there was a restrictor there?

ZIPPY

It does improve spool up especially on the 3 MY01 cars i've fitted it too.
80p each and 2 minutes to change, what more do you want.

Zippy

Miniman

iTrader: (2)

Where can you get them over here?

WRXKM

I have this in mine....

I am running Nos and only had problem with boost spiking (Hitting boost limiter) only when nos came in in 5th gear!

Used jet out of Webber DCOE Carbs and works extremmely well

Give it a try they are only pence

4wheel

iTrader: (2)

where from

submannz

Yep, I have many plans on how to use these restrictors, if anyone interested I will post them on my web site.

StickyMicky

link lol?

WRXKM

It was Teeside motor factors who fitted mine...
Would imagine most places that deal with carbs wil.l have them in

work a treat

Joth

I tried this in my MY98 JDM Forester, first of all the restrictors look nothing alike, mine was a brass insert in the hose between the compressor nozzle and the T junction, really small hole, less than a millimeter. I made two alternate restrictors with bigger and smaller holes, the smaller hole, less restriction, lowered my boost from 10psi to 7 psi, the smaller hole bigger restriction allowed it to spike up to about 13psi on acceleration and gear change but would go to 10psi when holding boost. Eventually I just went back to the stock.
But this is of course stock boost. No mods there

StanS

iTrader: (3)

Did it on my UK98 about two and a half years ago and ran it for about 18 months Used a 0.8mm orifice (part number22326AA260), and gradually drilled it out until it gave me the peak boost I wanted. This was achieved at 1.0mm. I used it with a second hand ppp ecu (£200), and with a decat exhaust and K&N filter (rest was std) - achieved 278BHP/268ft-lbs on RR with P1 achieving 289BHP running after me (for comparison).
It peaked at 21-22psi, and tailed off (thanks to ecu) to about 14psi at 6k rpm. Peak boost came in at 3k,so was excellent on the road. I used SUL and octane boost.
Then, "experts" said 280BHP on std internals was crazy !!!!
Now we have 400+BHP on std ! So much for experts !
I had it regularly (3 mnths) select monitor checked and it was fine. When examined (when stripped for upgrade) pistons were perfect.
Best power increase ever for £1.18p !!!!!!!!
Stan

Gridlock Mikey

sO DOES THIS DO THE SAME AS A dAWES EXCEPT WITH ecu CONTROL?

mIKEY (Sorry about the caps lock, can't be bothered to re-type

ZIPPY

Mikey, it isnt antwhere near what a Dawes will give you, it just allows the boost to build that bit smoother and earlier and increases the peak boost very slightly in the lower gears.The 3 cars i've fitted it too all said they could instantly tell the difference, me included.

Zippy

spence7

IT's not quite £1.18 though Stan is it surely ? Cos you wouldn't have gotten 280bhp odd without a remapped ECU as well. On the other hand I guess you wouldn't have seen 280bhp with a remapped ECU though if used without the restrictor ?

So using a bigger orifice only increases the rate of change of boost, not the peak ? Am I right ?

Jay m A

iTrader: (2)

Forgive me if I'm wrong but max power is seen way after the boost spike so this mod should'nt affect top BHP. This mod should give more low down torque when boost comes in - which on the road is probably why a difference is reported

Erm, I think

THOMO

if thats correct its amazing that remapping cost so much for less
gain.(safety would be my concern). nice one stan .have you had your car on a rolling road tune.

StanS

iTrader: (3)

Thomo - what do you mean "if that is correct" ? I am not in the habit of telling lies [img]images/smilies/mad.gif[/img]
If you need proof it was in the Jap Perf Mag July/Aug '01, page 68 on the Well Lane shootout article in Feb '01 !!
Author (obviously a knowledgable person ) said "21 psi is dodgy without STi internals" !!!!!
So what would he say now with people getting 470BHP on std internals !!!!!!!!!!!!!!!!!!!!!
Still, it was in a mag so what he said must be true !
Stan

[Edited by StanS - 6/13/2003 8:16:13 PM]

flatfour0

If this mod is so good why don,t every one do it?
I fancy doing it but not sure if it will do any damage to my engine.

StanS

iTrader: (3)

Good question - I was prepared for the worst happening, because of all the ignorant comments. I used SUL and octane booster, and had it regularly (3-monthly) checked on select monitor. And my engine/set up was fine. Can't say yours will be - but can't see why not if engine is checked like I did mine. PPP ecu had a lot to do with it I suspect - reducing the boost at "high" revs to about 1 bar.
Best £1.18 spent!
Stan

ScoobyKev

I had my P1 decatted last week and found that it was hitting fuel cut. Took the car down to Power Engineering and they imnstalled a restrictor, as it was peaking at 1.46 bar....they said it could bend a con rod. Now it boosts at 1 bar and still goes very well. At least I know it is running safe now

Regards

Kev

st33ly

Have tried this mod and have to say that spool up time is quicker and seems to pull harder. Have an MY01 WRX plus PPP. The mod did not even cost me anything as dad had a few small stainless steel Y pieces in his tool box. One question i do have though is will this cause my engine to blow up???

Regaeds craig

Turbo_Steve

A PPP -IS- a remap, of course. That's the whole point.
Changing the restrictor is simply reducing the ECUs control over boost levels. If you have a boost gauge (and a knocklink) then I'd go right ahead.

It's a "pot luck" thing. Chances are you can change the restrictor and have a car that feels lots faster because the boost builds quicker and peaks a little, and you will have no problems.

But if you are not monitoring knock / AFR then I can only advise caution: This mod should (at least) be treated the same as fitting a dawes device and monitored carefully.
Only changing the restrictor has LESS control than a dawes: A dawes achieves a specific boost and stays there. Changing the restrictor simply reduces the ECUs control: fine under normal conditions...but what happens in a boost spike? On a really cold morning? When you fit that super-de-cat downpipe?


As for the PPP ECU, as some of the later ones have been associated with running lean, pushing the boost beyond it's normal limits on one of these is something I could not advise.

I am sure some of the more technical folks on here will have better arguments than me.

At the end of the day, your factory fuel cut is likely to protect you from most nasties, but I'd still want to monitor it with a knocklink / AFR.

Just a final thought: driveability. I've had a car that boosts massively before the ECU reins it back into standard. It feels great, but lacking in top-end, so you end up stirring gears more. And you pull out to overtake, shoot forwards.....and wonder where the acceleration went?

StanS

iTrader: (3)

I fitted a boost gauge at same time as restrictor, as driving blind with any "iffy" mod is only for those with bottomless wallets. Its how I knew when I got the peak boost I wanted as I drilled out the hole !
Great driveability, as peak boost came in at 3k - as opposed to 4.4k with current set up (although this gives much bigger grin!)
Stan

flatfour0

How much is a boost guage? And were is the best place to get one?

Turbo_Steve

I strongly suspect you'll be changing it back when the temperatures drop. I had to Fuel cut is a horrible thing.