john banks

Pete YHM. The results I collected on an otherwise standard decatted P1 have not had comparison with the standard catted P1 so are not relevant. If the standard P1 retards this much on Optimax I would want a knocklink anyway.

[Edited by john banks - 9/2/2002 11:57:37 AM]

lubo

Having seen under the P1 for the first time I am a bit confused.

Could anyone confirm if the standard centre and back box have any restrictors or cats since I am thinking of having these changed.

If I change what system should I go for.

The car currently has a Magnex downpipe.

Thanks in advance.

Lubo

P1 8 YOU

lubo,

they definately have a catted centre section...i am on my second P1 now and have once again just had fitted the full scoobysport exhaust system which not only sounds the dogs bits but with the downpipe, backbox and de cat centre section gives the car that little extra bit of power...and all for 700 notes

p1doc

how do you find the scoobysport system,any problems with maf sensor?how much improvement in performance?a lot or just a bit?
also how much more noise as i have ordered a p1 wr back box,still waiting 7 weeks later,both subaru and prodrive advise against uprated downpipes
martin

MikeWood

P1 8 YOU

There is no centre cat on a P1

P1DOC

Silencers are now at Subaru


Mike

ChrisS/P1

I was going to get a P1 WR backbox until I investigated and found that the car will gain top end BHP, but will loose some low end torque.
Checked the price at my local dealer - £395 fitted.
I've decided to go for the ScoobySport backbox, as this is only £317 + fitting, makes a nicer sound, and increases both the BHP and torque.

lubo

I have done a little research on this and spoke to someone from Milltek who happened to be up our way today.

Bear with me since I am not technically minded and hopefully have this right.

The standard mid-section does not have a cat but is restrictive as is the back box. Milltek have tried loads of varients on standard scoobs and have found that the larger dia. un-restricted pipework affects performance due to lack of back pressure, pressumeably this will apply to the P1 also.

The product they have suggested is slightly restricted (gasses pass through in a straight line rather than being diverted first)only at the mid-section to compensate for this and bolts straight onto the Magnex downpipe.

The guy is willing to let me try this out and should have it fitted in two weeks.

If Mike Wood sees this could you comment further on whether this is safe and does the inrease in performance (if not a lot) justify the cost - £250 supplied + fitted.

Thanks

P1 8 YOU

p1 doc, from a personal point of view i love the s/s system...in terms of performace i have been told an extra 20-30 bhp, im not sure how accurate that is but it certainly feels it. It is noisy when it gets warm (but by no means outrageous)the only time it gets on my nerves is on long runs on the motorway...ive had them on two scoobies now and had no problems at all...

john banks

I told you you would get different answers from everyone! AFAIK the MY99/00 UK all have a centre cat except the PPP cars, and the STi5/6/P1 do not have centre cats. All have downpipe cats.

I removed an STi decat centre and a similar backbox to the P1 and swapped to something a little less restrictive and the results were good but not startling. Extra noise though.

MikeWood

Chris

I think you may have been misinformed. Our rear silencer DOES NOT reduce mid range torque. The performance gains will be similar to a Scoobysport silencer but with a less intrusive exhaust note.

Our silencer is £350 inc vat but fitting is extra. If you dealer wants £45 to fit it, find another dealer as it only takes 15 mins max.

Regards

Mike

lubo

JB/MW

Bottom line, performance wise, is it worth doing any more than de-catting the downpipe on a P1.

To everyone else I appreciate your comments

Thanks in advance.

Mike

MikeWood

Fitting the rear silencer is definately worth it. Most people report that removing the catalyst improves performance but all the cars I have driven in this spec run with detonation to varying degrees as the ECU is not mapped to cope. The car is also potentially illegal as it would almost certainly fail an emissions test, your warranty will be void (if the vehicle is still within warranty)and you may find the increased noise levels unacceptable...........stands back and waits for flaming by everyone with a decat

john banks

Lubo YHM. Get a knocklink and a boost gauge if you don't already before you do anything else.

[Edited by john banks - 8/30/2002 9:44:55 AM]

SCOSaltire

so a SS DP fitted to a MY99 with PPP is a bad idea Mike?

is there any good exhaust mod to complement this Prodrive Package?

p1doc

from the above posts does everyone have problems with downpipes or is it just scare stories?i am very tempted to get a downpipe but not if it causes problems.i just had a chat to pete croney who reckons downpipes are ok and he has customers with p1's who have done 60,000 miles with the downpipe with no problems
martin

john banks

Logged a P1 this pm with decat DP only. It was pulling out -1.5 degrees but it was cool and very wet, so thrash it around a track and it would be more. Pulling out a few degrees from the ignition maps cleaned it up a lot and it drove smoother - the dogdy zone was the overboost spike coming onto boost. When the boost was turned up the standard timing map was rather inappropriate, so a boost controller on a P1 would definitely be a bad idea IMHO. Also the P1 ran pretty lean compared to other UK cars. There was also a lean spot during spool up.

p1doc

do i need a knock link and a boost gauge just for a downpipe!!it sounds like a lot of hassle for the gains,is it true the ppp for the sti7 has a downpipe modification just to confuse issues
martin
to john banks -could you discuss this in detail with me if you do not mind,my work no is 01674 830361 bleep 7302
thanks,
martin

john banks

Tried to ring 11.30am but no reply to your bleep.

I will send contact details to your email as per profile.

The problem with the decat is that it appears to make the ECU hit areas of the map which are too lean. The P1 runs leaner and more advanced than other UK cars anyway and doesn't have the sort of run off on the map to cope with odd circumstances. This combined with boost spikes does put it nearer to the edge and from what I have seen I would not run a decatted P1 or STi without a knocklink. It may stay quiet but the safety margins are not great - on the UK cars you can put a new turbo and exhaust on and increase power substantially on the standard ECU and often get away with it and the timing and fuelling are sometimes still OK (need to be checked and depends on how far you go). Just my opinion others will disagree.

Now arguably improving the breathing and reducing exhaust backpressure should reduce the chance of knock, but effect is reduced or cancelled because the ECUs hits the "wrong" areas of the map and overboost spikes more.

The STi 7 and the WRX control knock in a totally different way and the ECUs are made by Denso rather than JECS - no comparison. However, some STis are having horrendous boost spikes from exhaust changes.

p1doc

many thanks for getting back to me,nice to get some straight answers re the "downpipe scenario"
martin

SCOSaltire

so u going for it p1doc?

Mike G

P1doc,

I have posted the results of JB's work on my P1 under "GENERAL" if you want to have a look.

My wife (lubo) has been more active on this site than me! so have set up a new username of Mike G - have a look.

As far as I personally am concerned the work JB has done on the car is very impressive and all within safe limits (0 Knock through all revs and gears). The final tweaks have still to be done but comparable results on the Dyno suggest John should have the car running at over 300bhp with the Dawes and better exhaust still to fit.

Regards,

Mike

p1doc

now i am very tempted to go get my ecu remapped,it looks the safest and easiest way of getting power but first my baby has to go to nursery(my real baby not my car) so i will be skint for a while as i have to pay off my new tyres,p1 backbox and uprated prodrive brakes
martin

SCOSaltire

did u get ur brakes done at fiskens?
fred was telling me how they fitted some and they are v impressive
1300 + vat

Pete Croney

Mike

How did you measure this then?

Det cans? Select Monitor? Knock Link? Delta Dash?

I have not seen any EXTRA det on a P1 from using a downpipe. What det there is, is no more than any Subaru engine produces as standard and equates to a fraction of what the ECU copes with in normally daily life.

As all modern Subaru engines run close to, or at the det point, your comment may be misleading people.

MikeWood

Pete

No need to resort to sophisticated methods here, it's audible.

Occasionally a std car will det and it can be heard in the car. The same car with a downpipe on dets more as the ECU is not able to pull the timing back enough. John has merely confirmed this with his recent work.

Mike

SCOSaltire

is the same true for a MY99 UK PPPed car?

john banks

My MY00 PPP + DP had zero knock correction in winter at least.

SCOSaltire

john
i getting full SS fitted on tuesday next week
can i come round after and see you?

john banks

You can if you like, but there is no need to.

SCOSaltire

dont have to maybe change the restrictor size?