mole

Does a PPP ECU increase boost over a standard ECU?
Whats the standard boost with a PPP ECU and whats the cut off? (1.2bar?)

Cheers

...mole

john banks

Yes, esp in the midrange up to 16-17PSI - about 4 more than standard. Cutout is supposed to be at 19.3PSI, but in reality unless a hose comes off you are likely to get the ECU adjusting the duty cycle of the solenoid by 18PSI to get things to come down smoothly before it happens.

However, PPP ECU still drops the boost at the top end which is a reasonably "Good Thing" with the smallish turbo - but you can add a bit more with a boost controller with good results.

mutant_matt

John,

I thought that the PPP ECU in itself, like the standard ECU, does not have any boost control - other than the fuel cut. I thought that the boost control is effectively done by the solenoid and the restrictors in the pipes. The ECU just allows a higher cutoff and just fuels differently? (but perhaps you could say that the ECU controls the solenoid so *is* controlling boost )

When you fit the full PPP, the freer flowing exhaust and intercooler pipework enable boost to build quicker and further, do they not?

Matt

john banks

"but perhaps you could say that the ECU controls the solenoid so *is* controlling boost"

Absolutely right. Most of the time the duty cycle depends on the RPM and throttle position and seems to behave like a dumb map (but the PPP one is different - it boosts earlier, higher and holds longer). Before fuel cut out the ECU actively tries to control boost if it sees it going highish. It does this by altering the solenoid duty cycle. Sounds like some degree of boost control to me - although it certainly is not a full closed loop system all the time. I don't think it really fuels that differently - both PPP and OEM ECU fuel on the basis of the mass of air passing through your MAF sensor, but it MAY be more aggressive with ignition advance - cars running the same boost say with a controller do seem a little bit more powerful with a PPP ECU. Seems the same from fiddling with boost controllers with the std ECU - just a whisker but I think there is a little difference.

"When you fit the full PPP, the freer flowing exhaust and intercooler pipework enable boost to build quicker and further, do they not?"

Then try taking a PPP ECU out and see the boost and performance drop. Most of the performance seems to come from the increase in boost due to the different boost map in the ECU.

However, there is at least the same again to be had with a boost controller as well

StanS

iTrader: (3)

Sorry to but into your thread, but my UK98 car with a '98 PPP has never cut out even peaking at 22psi on the boost gauge (accurate compared to RR gauge). Is a 98PPP supposed to cut out ?? May my cut out have been disabled (I bought it 2nd hand)?
Stan

john banks

According to Mike Wood the PPP does have a cut out but I have never hit it also accidentally peaking to around 22 PSI once. I think it is supposed to work on the amount of time it has been over 19.3PSI. Seems a bit of a lazy cutout to me! On later cars the solenoid will noticably oscillate the boost if you go above 19PSI peak even for a short time.

WREXY

Hi Peeps,

Regarding differences of a standard ECU and a PPP ECU with a boost controller running the same boost, look at this post from Andy Tang. Read from his 2nd post and down, on the page.

http://www.scoobynet.co.uk/bbs/threa...D=29443&Page=4

Cheers,

Wrexy.



[Edited by WREXY - 12/29/2001 12:56:53 AM]

john banks

I wouldn't have bought the PPP again, but when I got it I wanted something plug and play and for that it works very well. Would have bought an AVC-R if doing it all again. There are too many variations between RR figures on different days to say which is better for certain, but if there is any difference it is so small as to be not worth the money if you then fit a boost controller IMHO.

john banks

Having said that and just had my car on the Select Monitor, AWD motorsport (who sell Superchips) say that when you Superchip or increase boost the PPP ECU controls fuelling and advance much better than the original ECU.

StanS

iTrader: (3)

Thanks for reply JB. Still don't think my cut off is working - it must need a lot of time over 19.3psi to cut out !!
Stan

john banks

Sorry I started another thread with a question of who had had a fuel cut in PPP and what boost it occurred at. Should've maybe continued here. I thought it was 19.3 because that is 1000mmHg and on the Select Monitor when it hits that even briefly the solenoid brings the boost down on MY99/00 at least. But with my solenoid now disconnected I want to know where the proper fuel cut is. I am sure Dowser said his was around 1.3-1.4bar.

john banks

WREXY - looking again at the thread - Andy could tell the difference with PPP and OEM ECU with exhaust bits but no boost controller and there was a modest difference. However, with EBC there was 20 lbft LESS with the PPP ECU than OEM but he could tell no difference. You need runs on the same day with a boost controller and the PPP and OEM ECU to tell the difference and as far as I can see no one has done that yet. To me just shows how crap RR results are. The effect of a boost controller on the road is massive over PPP compared with the difference in the dyno graphs. A lot of that is probably different part throttle and spool up behaviour.

Who knows if the Prodrive ECU makes any difference at all when you up the boost. I suspect there is a little bit.

WREXY

Hi John,

There would definately be quite a big difference between the PPP ECU and the OEM one. As you said it's just when you up the boost on a standard ECU that there seems to be little difference. However if the PPP ECU does fuel better at higher boost levels, the PPP ECU is worth having even for safety alone.

How's my m8 Beasty going? Has he fitted his Dawes yet?

Cheers,

Wrexy

john banks

He's kept quiet on here, but I think he enjoyed the run in mine the other night and was going to fit his Dawes soon.

WREXY

That's good to hear. I'd love to have been there too, with the testing. I love these sorts of experiments. Trialing and testing. I've enjoyed reading your findings. Some very valuable info coz it also relates to my car with the EBC. Keep it up m8

Cheers,

Wrexy.

Bitten Hero

Also check out John's other thread for more stuff on this... I definitely got cut-out but only when it temporarily went beserk at >25psi (see other thread)

Cheers
Richard