Pete Croney

Someone asked me a while ago what the emissions were on the new WRX, with the turbo back cats removed (there's still a small one in the manifold), but I can't find the thread. So here's the data...

Emissions

Tested today, from cold...

Idle
HC 46ppm
CO 0.05%
Lambda 1.01

Fast idle (2500 rpm)
HC 5ppm
CO 0.18%
Lambda 1.00

The limits for legal road use are
HC 200ppm
CO 0.35%
so the car passes EU emissions

The tests were conducted by an MOT station. I suspect the high HC on idle was due to the car being cold (it had stood for 4 hours before the test).

Performance

On PE's rollers it produced 244bhp at 6573rpm and 233lbft at a basement scraping 2600rpm. Comparing it to another WRX with a Prodrive "non PPP" backbox, power was up 12bhp at high revs and 30bhp at low revs. Torque at 3000rpm was up 49lb. Peak torque was achieved 600rpm lower than the backbox only car, which peaked with 216lbft at 3200rpm.

No one turned up with a completely standard WRX to compare.

Squizz

Interesting, and encouraging figures...Don't suppose you have similar stuff for an MY99 do you?

I also assume those tests were carried out with the car running on Super Unleaded...?

Regards,
Squizz.

DT

Looks good Pete. Did you do any emissions & power output tests on the full decatted system?

Pete Croney

DT

The only cat left is the one in the manifold and I am planning to leave this in place.

Miles

Can I add to Squizz's request but for a UK98MY without the centre cat? Not bothered about power but emissions would be very useful.

SimonD

Pete,

this sounds almost too good to be true. Are you saying that in this state a de-catted MY01 will give these power gains and still pass a MOT test?
Why the difference to the old models? Do you think that it is down to a more efficient motor or the cat that remains in the manifold?

I assume that noise levels will be over current limits but how do they compare to a fully de-catted old shape Impreza?

Sorry to bombard you with questions but I have been out of Impreza ownership for 18 months now and (looks aside) it seems that the new model addresses most of my criticisms of the old one. This kind of news only adds to the attraction.

Cheers

Simon

sgould

Before I have mentioned about the legality of removing the cats, but recently I have also found that a MY99 will easily pass without a rear cat.

The rear cat is only there for certain other countries.

Off comes my cat

BugEyed

Pete

Your results look very interesting. Just one thing is bothering me - what was the exhaust system that you were using? Had you "just" bypassed the central cat, or had you put on the full ss exhaust?

The reason that I ask is to try and understand how much of the benefit was down to the removal of the central cat, and how much down to the rest of the exhaust.

Duncan

Pete Croney

Simon

Yep, exactly that.

I think it is a combination of having a cat in the manifold, where it gets very hot, very quickly, and an increased efficiency from the engine.

Noise levels are slightly lower outside (no tests done), but considerably lower inside the car.

Duncan

It is a full straight through system. No bypasses or anything fancy.

Squizz

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by sgould:
<B>I have also found that a MY99 will easily pass without a rear cat.
[/quote]

Ooooooh...Interesting...

scoobysnacks

Excellent - didn't know about the manifold cat in the 01 model, which seems like a good idea.
One thing though, can you put to rest the arguments about which cars (pre 01) have the center cat as standard ie. UK (I know this does), standard WRX, STI, P1?
I've seen conflicting info, but I guess you've seen them all up close or in bits. I've got a standard 98 WRX and was wondering if this did. Looks like it might from underneath but I've been told the box on the center may just be a silencer..?

Thanks for any help.

Pete Croney

Centre Cats fitted at factory...

All UK.
All WRX (import)
All STi up to part way thru Version 4 production
Most 22B (can't tell without looking into the pipe)
All 22B UK
All P1
All WRX01

No STi 5 or 6

Theo

Great news,...just 28 days too go

Mad Max

Me too Theo... About 28 days. What did you order ?

I ordered a beautifull WRX Station Wagon Black-Blue something (Can't remember the color name

I was in your lovely country on holidays about 2 weeks ago... Loved the people ! Superb landscape... Awfull weather, but that's what I was expecting :-)

Steve vRS

Excellent news!

On straight through exhaust on the Christmas list then.

Steve

vmax

Pete,

How much for a setup like this then ?

Kev S

OK, I'm new to Scooby ownership and Scoobynet. Picked up my WRX MY01 on Saturday and I'm already thinking about upgrade options. Any advice would be welcome. This thread looks interesting and here's a question for you all.

I was planning on a PPP. At the moment it's not available and not sure what kind of gains it is this likely to give? I believe this only replaces the back box and leaves the centre cat. Is the straight through exhaust a viable alternative to a PPP, with those kind of Dyno figures. Plus, whats the legal implications? It comes within the MOT emissions, but isn't it illegal to remove the cat?

Also, what make is the exhaust and how much Pete?

RonaldoH

Kev, its a scoobysport model. Petes own, and frankly they rock.

&lt;Drives around with rear windows 1 inch lower for entertainments sake.

Rgds
Ronnie

Jza

Pete,

Thanks for the figures mate. Flippin marvelous!! I understand you fit a small box that prevents a problem with the cat sensors saying theres an engine fault (???).

I know your an independant company, but i wonder if you could offer some advise on someone else's product. I, like many others are awaiting the PPP for the MY01 WRX to see what it offers. I really want your exhaust, but am bothered that if i fit it and decide to have the PPP the whole lot has to come off. Is that what happens?

Can you have YOUR exhaust and a PPP at the same time? Is it worth having both or are there problems?

Any advice would be appreciated!!

Jza

RichieB

Pete....

Thanks for the emissions data on the MY01...I was the one who asked direct to your website...excellent news.

I think the only other query I had left over was over warranty implication. Although the characteristics of the engine are changed by the breathing of the exhaust, will this in any way affect the Subaru UK warranty on the non-ScoobySport components? So if the engine goes pop, will Subaru come back and say, "well you had non standard performance parts fitted, so the failure is down to you"? From the threads i remember i think the answer is no?

Cheers,

Rich

druddle

Kev S - PLEASE run the car in before modding it !!!! I would leave it till at least 6000 miles.

Mine has 4000 miles on it and it really goes like a rocket compared to when it had 1500-2000 on it. I am seriously considering the Scoobysport exhaust after the 7500 miles service.

I am sure Jza will say the same thing about running in !!!!!!

Dave

Tiggs

pete,

my question is the same as jza- can i run a ss pipe with the ppp or is there no point or benifit??

tiggs
ps if the onnly benifit is noise then that might be good enough, i belive the ppp is quite quiet??

Kev S

Dave,

I'm sticking religiously to the 1,000 miles running in at 4,000 rpm max at the moment. 300 miles ish at the moment, so oil change should be a week on Saturday. I've been told to then take it carefully for a few thousand miles. How many before giving it some.

I drove a demonstrator with 8,000 + miles and yes it was quick. But, I'm never satified so anticipate I'll want more. Just wondering if I would be happy with a complete exhaust, i.e. removing the centre cat. Or would I end up going for a PPP anyway.

I'm also concerned that a complete exhaust, such as the one from Scoobysport will be too noisy for me. Are they loud or just louder and sound nice. Before and after decibel stats would be useful.

Kev S

Pete Croney

A couple of questions to answer...

I'm sure that the PPP will be a great product, following the previous trends of good torque increases and better "real world" driveability. Something I have always rated as far more important than peak bhp.

As before, Prodrive will be supplying their own centre and backbox sections with the PPP and would want the car to arrive at Banbury in standard form.

I would want to do a lot of testing before fitting a downpipe to a PPP WRX. It works brilliantly with the PPP on the previous models, but we did a lot of testing with each year's car to check it was 100% safe and reliable before we promoted this option. We would want to do the same before recommending it on the WRX. We will be doing as soon as the PPP is available.

With regard to warranty, this is always a matter for your dealer. 60% of the WRX exhaust systems we've sold have gone to dealers, some to be fitted to customers cars, some for their own cars/demonstrators. We are proud of the fact that our exhausts, whether a full system or just a backbox, have never caused a fault with a customers car. After all, the PPP will typically produce about the same power and a bit more torque than our exhaust systems and Subaru UK are happy that the drivetrain can cope with these outputs.

I don't think the mileage at which you fit a better exhaust makes any difference. You can have it fitted at PDI, provided you still comply with the running in guidelines. Its no different to picking up your new car with a PPP fitted.

vmax... all four exhaust sections work out at £605.00+vat

Tiggs

jza, just off subject a bit- how dark did you go on your window tint front and back?

tiggs

Pete Croney

Kev

A full exhaust on a WRX is about as loud as a backbox only, on the 99/00 car. Inside the new car, it is considerably quieter.

At Bedford, I was tested at 86dB at 4500 rpm at 0.5m from the tailpipe.

Tiggs

pete,
if the ppp is a bit quiet is it as simple as swapping their back box for yours? or does that cause problems?

tiggs

Theo

Madmax,....I ordered the WRX 4-door in December 2000,....and also in the colour Blue-black !



This is the Demo wich I have driven in December last year,...the headlights and Gold wheels are done by Photoshop5.0

The Full SS exhaust is the first mod that I did on my MY99 car,..and now again for the WRX.

I think the SS exhausts are simply the best !!




[This message has been edited by Theo (edited 03 May 2001).]

[This message has been edited by Theo (edited 04 May 2001).]

Iain P

Catalysts work extremely efficiently when they are new. Emission levels that manufacturers claim are on catalysts that have been aged to approx 60 000 miles. Their efficiency in this state is greatly reduced. Your tests do indeed show that a small 'starter' cat will achieve the emission levels, but it won't several thousand miles later. Also, the emissions at idle are only a small part of the story. The starter cat is there (usually) for start-up purposes only as it needs to start converting within 10 seconds (say) of start up. The larger cats take-over when they are up to temperature. Starter cats cannot convert the required amount of emissions throughout a complete drive cycle which manufacturers must achieve. I believe that this is why the new laws will state that you must retain the original set up (i.e if it was design with starter cats and under-floor cats, then that system must remain) 'cos it's easy to fiddle an MOT emissions tests. If you plan on selling exhausts in the future, then you'll need to get into this!

Pete Croney

Hi Iain

I now fully understand what you meant.

The new WRX is a "world" car. It is sold into territories that have legislation much stricter than the UK/EU MOT. In some of these territories, the vehicle must not vary by more than a few percent from the emissions that the vehicle produces when new. If your theory that a manifold cat is only good for a "few thousand miles" is correct, what happens in these territories and also what happens when the cat breaks up, just in front of the turbo?

My figures were not meant to mislead. They are meant to show that a car with 5,000 miles on it and no cats after the turbo will pass the current MOT. I cannot predict what legislation future governments, here and abroad may adopt. The fast idle test was conducted approx 10 minutes after the slow idle test and the manifold cat appears even more efficient when the car has warmed up.