Andy Tang

iTrader: (3)

Iain P

That 2nd one has scarey overboost! 22 dropping back to 17! Darren, 1.5 bar seems very high (approx 22 psi) - what does it settle down to?

Darren Thompson

It settles to 1.15/1.2 bar and the car does move like a F4cking freight train. As I have said no over boost or engine problems such as heavy fuel usage. The idle is correct at -0.6 bar as the guys at Subaru have confirmed so if anyone at Prodrive reads this please comment. The only other thing it could be is a faulty boost gauge which is a Superchips gauge and they claim to of never had any problems with them.

Darren.

[This message has been edited by Darren Thompson (edited 02 February 2001).]

Darren Thompson

Right I have fitted to my MY98 a PPP ECU, Piper X induction kit and a decated center section with a back box, the boost gauge which is connected to the blanked off out let on the inlet manifold under the coil pack where no 3 is fed from. The problem is I get readings of over 1.5 bar when booting the car in 3rd, 4th and 5th which would mean engine melt down on the car as it is a UK car. Has anyone out there got any ideas what boost the engine is running as there is no over boost or problems and why the gauge is blasting off the end of the world like this ??? When the car is on idle the gauge reads - 0.6 bar and when engine braking - 0.7/0.8 bar which I have been told is correct.

Darren.

Yex

Darren,

I don't know what the values are in "bar" but when I had my PPP ecu reset on my RB5WR it was holding around 15.5psi.

Yex

Danny Fisher

Shame the driver can't handle that amount of boost!

Dan

Yex

Oh hello it's Dan the man

I can handle it, but only on a good day

Regards

Yex

Stef

Darren.
Bear in mind that the PPP is not designed to run with induction kits and cat-less exhausts, both of which will increase boost.
My car peaks at 18psi (1.25BAR) in these cold conditions and holds 15-16psi (1.1BAR).

Edited cos I'm a logger!

Stef.

[This message has been edited by Stef (edited 13 February 2001).]

Iain P

Darren, your car is obviously overboosting cos the turbo is spooling up quicker and sooner and the standard restrictor (damper) can't do it's job. You'll find that if you increase the restrictor hole in 0.05/0.1 mm increments you will find the correct boost ramp-up rate. The same obviously happens with Stef's but not to such a high extent. The reason for the overboost is that the hoses to the wastegate and bleed solenoid take a while (milli-seconds) to 'fill'up' with boost and by the time the solenoid opens to bleed some of it off, the boost level has already shot up. So, the only way to get the wastegate to open a bit earlier is to fill the hoses quicker by increasing the amount of boost passing thro' the restrictor. I would suggest that the PPP doesn,t have the standard cars 18 psi (ish) boost cut-off so anything over this would be a bit risky! Like Stef said, the PPP only works correctly with specific exhaust and inlet losses. By the way, you can buy tiny drill bits from most modelling shops.

Iain P

Oh, Stef he did say he has -0.6 bar at idle. Shouldn't be 0 at idle! Shame on you

dowser

My00 PPP; 1.3 bar peak, 1.1 held. Only induction mods are a removed resonator and ITG panel.

Fitting a dp this week - will see if it increases.

Can someone from Prodrive *please* tell me the PPP ecu still has overboost protection?! Mike?

Cheers
Richard

Darren Thompson

I am running the actual supplied center section for the PPP ECU, and yes you will get a minus boost pressure on idle due to the engine is drawing the air in and not having it blown in by the turbo. All normal induction cars run a minus pressure on the inlet as they draw the air in, the reason the pressure rises from a minus figure is the butterfly on the carbs or throttle body open allowing more air in and less resistance. On a turbo car the turbo spins up and forces air in causing a plus figure and boost.

Darren.

MikeWood

Richard

Yes the PPP ECU does still have a boost cut safety feature, but fitting a different downpipe may mean that you occasionally find it!

Mike

dowser

Thanks Mike - understand! Still preferable to the alternative if it had no protection

Cheers
Richard

Darren Thompson

Mike my car does not hit the overboost cut out even with these readings, the car is in the dealers tonight for some work so I will as them to put the monitor on and get back to you all.

Cheers Darren.

dowser

Darren

Sounds like a faulty guage.....or some tricky pipework/bleed-valve?

Richard

Stef

Me needs glasses methinks!

Stef.

Darren Thompson

Anyone with a boost gauge I can try in the Manchester area and anyone with glasses for Steff in the Northampton area ????

Darren.

Darren Thompson

Had the car at Subaru last night and the car is peaking at 1.4 bar and leveling out at 1.15 bar so the gauge is a little out but this is good new as it means I wont be melting any UK chocolate pistons. Cheers for all the help and advice guys next to get it on a set of rollers.

Darren.

Iain P

Darren, 1.4 bar still seems bleedin' high! That's about 22 psi! Thought the std ECU could only cope with 18 or so? Although the boost held will be OK, it's the overboost that'll do the damage.

[This message has been edited by Iain P (edited 06 February 2001).]

Darren Thompson

Ian the car is going to be played with this weekend and a P1 restricter fitted to reduce the sudden build up of boost. We also have the use of some proper measuring equipment this weekend so I will let you know on Monday.

Darren.

Bob Rawle

Hi, tell whomever to be careful as the P1 restrictor is smaller than the UK one and may push the boost higher. Try it with a 1.2 mm and see how that is.

Iain P

Hi Darren, the only way to reduce the sudden build up is to increase the restrictor hole. Think you'll find there is only one optimum size hole to eliminate the overboost for a given setup and it will certainly be larger than the 1 you have. You'll need a set of small drills and start experimenting.

Darren Thompson

Right ran the car with the monitor from Subaru and this is what we got.

Max peak boost = 1.293 Bar.

Constant boost = 1.15 Bar.

We did get one very high reading but this was on a quick gear change from 3rd to 4th going back hard on the power the reading was 1.49bar. The next job is to fit a larger restrictor.

Darren.

dowser

Hi All. Darren, do you have any further news?

Fitted my SS dp last week (and refitted OE mid section with cat), onto a my00 PPP with the resonator removed. Goes like a *%#@# rocket....but;

1.35 peak and 1.15 held (1.3 & 1.1 before).

These figures don't tell the whole story though - that peak figure is being held for about a second and feels waaay too long!

Anyone else with a PPP'ed car who fitted a downpipe had similar? Or problems later if they didn't have a boost guage?

I've currently refitted my old STi backbox while I investigate the options (seems this is as restrictive as the OE downpipe )...and await the arrival of a knocklink module/sensor

Thanks
Richard