crispyduck

iTrader: (1)

Dear all,

Thought I would post some feedback on what must be the cheepest combination of mods for our Scoobies. This is effectively all courteously of the ScoobyNet community as this is where I did all the research...

The Car: MY03 WRX

The Mods: (a) Dawes, (b) Decat OEM center, (c) Decat OEM downpipe, and (d) Optimax.

Cost Summary:

For a little less than £156 my MY03 looks absolutely standard from the outside, however feels and sounds much different! Note, my car will not pass an MOT test. I'll swap the exhaust (hopefully center only) when the 3-year MOT grace period is over.

Detailed Cost Breakdown:

• Dawes was imported (during Nov 2001) direct from DawesDevices in USA - £19.50 ($35) including shipping. To make this thing 'safe' on part throttle I drilled the bleed hole in the Dawes out to 1.5mm. Dawes is set to increase boost by approx. 15% so that it is under the standard fuel cut.
  
• Decat OEM center (number 1 in the diagram below) - I purchased a second-hand 1yr old standard OEM center pipe for £25 which had the CAT in. Basically I bashed the CAT out and got my local tyre/exhaust fitter to install it for £10 (whilst replacing my tyres!). Bashing the CAT out of the center pipe was easy, took around 20 mins using a drill, a long handle bladed screw driver and a hammer.
  
• Decat OEM downpipe (number 2 in the diagram below) - I purchased an 'as new' (only 5 miles!) standard OEM downpipe for £9.99 off eBay which had the CAT in. Again I bashed the CAT out and got my local Scooby specialist (not main dealer!) to fit it for £90. Bashing the CAT out of the downpipe was much harder - look at the shape of the dame thing! Took around 2 hours to get it all out.

History of Mods:

Below is the order I installed the mods to my standard MY03 along with a little feedback on how each effects performance - both good and bad points.

Dawes

• The Dawes was first, as I purchased it for my MY00. It went straight on my MY03 after I'd run it in.
• I used the Dawes to slightly increase boost but mainly to improve turbo spool up. Used a Dawes for over 3.5 years now.
• Car felt much quicker (on MY00 and MY03), especially on my motorway commute to work where overtaking was much improved. Basically you don't need to change down if you are feeling lazy.
• The cars handling is affected as you now need to 'bleed' the power on using the accelerator say round corners or off roundabouts. Some might assess the handling to be a little 'twitchy' but once your used to it you'll learn to enjoy it.
• With the Dawes, i.e. boost not controlled by ECU, the car doesn't run quite as smooth when driving slowly with revs under 3000 RPM. This is only slightly noticeable as passengers would not even notice. My best guess is that the Dawes struggles to maintain a smooth boost profile when using very low boost. I thought about getting one of the more expensive Dawes devices which have a lighter ceramic ball. On the web site it says it is more responsive however I could not find enough people on here to independently confirm it makes any difference in the real-world.
• Back when I first started to use the Dawes there was concern on here with how it operated on part throttle. The main concern was that too much boost on part throttle could lead to lean running. From peoples trials (I was keeping up with John Banks' feedback) it seemed that opening the 'bleed' hole on the Dawes to 1.5mm would help. So this is what I did as did many others.
• Personally I was also keeping an eye on the boost at high revs in say 4th especially when the car gets hot perhaps waiting at traffic lights. I found that the Dawes seemed to drop a little boost at high revs as it got hotter. This made me feel a little more comfortable as this made things a little safer.
• So Dawes was great for me on MY00 and MY03, as long as you keep boost to a sensible level (under standard fuel cut). When the car gets serviced by the main dealer it takes me 5 mins to remove it and but it back to standard.

Decat OEM center pipe

• Why? Well I did this for two reasons. (1) if someone looked under the car, say during a service, the car would still look standard and (2) because the research on here shows that what I have done here is as good as an aftermarket decat pipe.
• With the decat'ed standard OEM center pipe now fitted to my MY03 the car sounds slightly different. New age cars seem to have lost the Scooby 'burble' on tick over compared to my old MY00 classic. Anyway the decat'ed center pipe has brought it back.
• 'Normal' performance doesn't feel that much different. Although the car does seem to be slightly happier above 5500RPM to the red line. I assume it's breathing a little better now. Given that I don't rag the car through the gears every time I drive it I didn't feel this gave much more every-day performance. With that said if I wanted the occasional race off the 'lights then it seemed to be a little quicker because you could hold on to a gear for a few more revs.
• In summary, Scooby 'burble' is back and very slightly better at high revs.

Decat OEM down pipe

• The latest edition is the decat'ed standard OEM downpipe. I did some research on here about decat downpipes. By far the best I found was the thread called Uppipe FAQ: Read if you are thinking of buying one. It concludes that what I have done here is as good as an aftermarket decat pipe. The instructions to gut your stock down pipe are here.
• First thing you notice with the decat downpipe is an even better exhaust note on tick over - even with the standard pee-shooter back box!
• You can now hear the 'whistling' of the turbo as you accelerate slowly to 3000 RPM in the first two gears. This is not noticeable above say 30-40 MPH.
• Performance is very much improved. Car comes on boost around 400 - 500 RPM earlier and pulls much harder throughout the rev range.
• The revs now seem not to slow up all the way in to the red. It's dame good!
• Gear changes on full throttle are easier and seem to keep the turbo on boost - less performance drop off between gear changes.
• The car is also really smooth at low revs again. This was a slight annoyance when I fitted the Dawes but its great now.
• This is a strange one, but the car seems to engine-break a lot less now when you are coasting in say 5th gear behind traffic on a motorway.

Summary:

Basically for £156 the car is much faster than standard, although not really sure how much power I've gained on paper as I'm not very interested in rolling roads. If anyone wants a guess be my guest – it feels like quite a lot!

Anyway, hopefully this was an interesting thread if you've got this far! By all means add your feedback if you have similar mods.

I'm now planning what next. I think the next thing might be TEK 2 or 3 but not really sure how much difference it will make. Let me know if you have any previous experience here.



-Steve.

TonyBurns

iTrader: (3)

Nice write up
Gives people alot of info to tune scoobs pretty cheaply without pushing it too far

Tony

fastfrank

yep, nice write up. Good that someone has taken the time to feedback some results.

two questions:

• Whats a DAWES devices?

• I'm thinking of decating similiarly but considering using the 'sport's CATs' instead. Might anyone know if they are any good?

Cheers
Frank

crispyduck

iTrader: (1)

Frank,

Q: What's a DAWES devices?
A: Simply put a Dawes is manual boost controller. It replaces the electronic 'bleed' control you currently have. The Dawes Manual Boost Controller web site describes it in much more detail. After reading this, if you have more questions just let us all know.
I use a Dawes but there are other makes that do the same thing. One other I know of is the GBE Boost Controller. Again they have good documentation on their web site.

Note: I have no connection with any of these companies, thus am not performaing any stealth advertising!

Below are a couple of snaps of it fitted to my MY03:



Q: Are sports CATs any good?
A: I have no experience of sports CATs so recommend others with experience comment here. From previous research they sounded very good releasing a lot of the same power from a full decat. The main advantage is that your car would still pass an MOT.

Hope this helps,
-Steve.

lumutwrx

Hi Steve
Do you get engine error message after you took out the cat?

Cal

Floyd

iTrader: (9)

Steve,

I've done all what you say over 3 years ago along with porting the OEM headers! The exhaust mods on their own made 233BHP at PE. The DP mod was the biggest improvement though. I added the dawes and it initialy felt better but it was crude and dangerous so it was replaced by an ECUTEK remap.

I got my exhaust parts free from scoobysports dumpster! (When they were still trading).

It's a good plan but you'll want more...See my thread in projects!

F

Aztec Performance Ltd

iTrader: (234)

Excellent write up.

My choice of 1st mods on a budget too. Decat+Dawes.

Not sure if its worthwhile 'gutting' oe exhaust as aftermarket decats can be had for little money secondhand.

Personally like the way Dawes controls boost.

As for going further.....its a slippery slope from here with turbos, i/cs, gearboxes etc.

I found it makes a nice reliable package without going too far.



Bob


PS. The more time you spend on here, the more crazy things you'll do to your car.

crispyduck

iTrader: (1)

Cal,

Yes I did get the CEL light up telling me there is a problem with the CAT - little did the ECU know that it's gone!

Anyway this weekend I've just done the 'CEL fix' as described by the Uppipe FAQ.

See below for a few snaps from my install:



-Steve.