Hey guys - just a few images of the BCS Golf Gti MK 7 we developed back in January...
Thanks for looking
Nige
Golf GTi MK7 Down Pipe Installation and review by Gregv
Finally installed the downpipe and wanted to do a comparison.
The downpipe is from BCS/Powervalve in the UK. It's a full 3" (76mm) system with a coupler to mate to the stock exhaust. The cat is a 100 cell metal cat instead of the stock 400 cell (which is ceramic I think). It maintains Euro 6 emissions compliance.
As you'll see form the pictures below the design is MUCH better than the stock DP. Nige over at BCS was a total pleasure to deal with and his enthusiasm and eagerness to talk about the product, cars in general, and development is reflected in the product. The quality is first rate and I've seen lower quality items sell for significantly more (in fact this is one of the cheapest cat downpipes I've found) so value is excellent. I got the system for around £550 (can't remember exactly) shipped to Italy.
Part 1 - COMPARISON
Here is a side by side comparison of the 2 DPs next to the car. As you can see, in addition to the larger diameter and multiple improvements in the various bends, the cat is much further back which also helps flow since the gasses will actually be entering the cells in more of a straight line.
One of the areas that impressed me the most is the sheer quality of the flex joint. The stock one is an incredibly basic accordion design with a bit of protective mesh while the BCS one is a hefty ultra high grade full steel cross woven design. It is MUCH less floppy (downright stiff) despite being slightly longer. Note that some even high end DPs like the milltek have only 10mm flex tubes (half OEM length) and I've seen some reports of them failing.
The biggest improvement has to be the inlet. On the stock unit you see an immediate bend of MORE than 90 degrees (110ish?) where the pipe actually flattens (it's even thinner than it appears because some of the already flattened width you see below is heat shielding) and then it immediately hits the 400 cell cat. Not only is the bend horrible, but you're then introducing the biggest point of resistance right after, and the gasses are certainly not traveling in a straight line to enter the cat too. Basically a terrible terrible setup.
On the BCS downpipe, you can see there is a much bigger pipe diameter on that bend and the bend radius is also bigger so the gasses are not hitting a wall head on. Then the cat has been moved downstream almost 2 whole feet so there is way more space for the gasses to cleanly and quickly exit the turbo and straighten out a bit. The cat entry angle is also much better, and helped further bu the fact that the cat would present less than 1/4 the resistance due to the reduced cell count.
Part 2 - INSTALLATION
In typical Greg (Ghetto) style. I did this on the side of a quiet road with a jack and a jackstand. Halfway through I realized something and asked myself "Why didn't you bring your Rhino ramps, you idiot?". Oh well, next time.
You will need:
Flathead screwdriver
mallet or chunky tool to tap screwdriver
10mm socket or wrench
13mm socket (medium depth)
15mm socket (BCS specific)
22mm O2 sensor socket
6mm Allen/hex socket
Ratchet
various extension lenghts
I would recommend a breaker bar too.
Steps:
1. Raise front of car on jacks/ramp. Go kill an hour for the cat to cool down.
2. Open any needed doors/trunk and disconnect battery using 10mm wrench/socket (I had left the DP in the trunk , electronic locks - oops)
3. Disconnect the O2 sensor plug just above/behind the airbox and run the wire out of the 3-4 clips/supports along the firewall.
4. Use the cable to find your way to the O2 sensor just behind the cat, place the O2 socket and use a few extensions to attach ratchet/breaker bar and remove sensor. Set aside in a clean place.
5. Use 6mm allen to undo turbo clamp. Once all out, pry apart with screwdriver, use mallet to tap as needed.
6. There are 2 small brackets welded onto the cat. These have a 13mm nut that holds it onto other small brackets. Find the nuts and remove these. Both are visible from the top through various gaps and easily accessible with a ratchet and medium length extension.
7. Get under the car and remove the cross brace just before the resonator. Four 13mm bolts.
8. Loosen the clamp between DP and resonator (two 13mm bolts) and slide the clamp all the way backwards onto the resonator section.
9. Still under the car, the DP is fixed via 2 rubber bushings. Forget about trying to pop them out with the DP in the car and just remove the plate the bushings are on.. (two 13mm bolts)
10. The DP is now fully disconnected. If it hasn't detached from the turbo mouth when the clamp was removed, just pry a bit with the screw driver.
11. Enjoy the next XX minutes trying to figure out how to angle the DP during every inch of movement pulling it out from the bottom. Swear as profusely and as loudly as needed.
I had a particularly hard time at first because I kept getting stuck on the diff's hydraulic unit. You have to twist and turn it quite a bit to get it out, and keep changing the angle as you progress. there is no "clean through" angle, and towards the end it will get snagged on the reflective foil in the tunnel and you'll have to press/bend it a bit to get it out.
Install is the same as the above in reverse with the following exceptions:
-With the BCS DP being build quite differently you have to take a slightly different path but it's easier overall. Initial entry is trickier due to limited space (without a lift)and the rigid flex pipe.
-The 2 nuts that help the cat are no longer used
-You will need the sleeve to mate the DP to the stock diameter pipe (15mm socket on the BCS). Note to not angle the clamps downwards, or they will hit the cross brace
-The O2 sensor location is significantly further back than OEM. You must route the cable directly from the plug to the bong in the straightest line possible otherwise it will be too tight. No longer route it through the clips (impossible) I also recommend removing the clip from the firewall bracket and just zip tying it. This will give you precious inches of slack which are probably a good idea.
Total install time (not including cool-down) of less than 2 hours.
Don't forget to reconnect the battery. Interestingly when I started the car I had a christmas tree on the dash. At first I though it was just going through the error messages, but I was left with 4 system errors (hill assist, TPMS, ESP, something else), not including a start-stop system error. Even the park assist button was blinking. All errors except the start-stop went away within 30 seconds of driving. Went back home, spent 2 hours fruitlessly searching the net for how the system worked to try and diagnose what sensor I damaged or whatever only to find the error gone when I got back to the car. So if you see your dash all lit up, heed Douglas Adams and "Don't panic!".
Part 3 - FIRST IMPRESSIONS
1. I was prepared for a slight loss of low-end torque, but no actually, the car actually seems to pull stronger from idle. This was the first thing I noticed.
2. Throttle response is noticeably improved (next 2 items relate to this somewhat)
3. Turbo spool up happens sooner and is smoother (there is much less of a "jump" from off-boost to on-boost)
4. Car is much livelier at higher revs. Whereas the engine flattened noticeably (that push in your back ended) at about 5000rpm before, it now seems to carry on well into the 6000 range and the drop-off is also softer.
5. Definitely gain in power all around as you can figure from the above. No figures but the fact that the butt dyno can feel them indicates at least a solid 5% increase in the powerband and a noticeable extension of the powerband which might be big news for the peak figure.
6. Noise - I was pleasantly surprised by this. There is a marginal increase in volume, but more importantly the sound is much nicer. It's throatier but not rumbly or raspy. It's just a little richer and more satisfying. It puts a smile on my face, but a passenger wouldn't notice the difference during normal driving. It would have been a perfectly acceptable stock setup. If there is any additional drone it's barely perceptible over tyre noise. it just sounds a little less like a 4pot and a little more like a burbly V6.
A note about noise: I think the sound a car makes is a huge part of the experience and affects how we perceive things. 2 cars with the exact same performance but with one sounding better will drive the exact same. However the one that sounds better will SEEM to be faster. The effect is much like driving without or WITH a hot slightly sweaty girl in a bikini in the passenger seat. Everything seems better WITH, even if it is really not measurably different. I have tried to remove the "bikini effect" from my observations above (1 through 5).
That's it! So far I've done about 50 miles of spirited driving, no CEL's.
EDIT: Put another 50 miles on and I think I may have been understating the performance gain. Maybe the ECU is adapting because I am scratching my head at just how fast the car is. Yes the stock DP is terrible but is it really possible there was this much choked potential?? 40-80mph highway merges across 3 lanes are happening in like 2 seconds, definitely under 3. I caught myself literally laughing out loud saying "MAN THAT'S QUICK!" from the surprise. I obliterated a Range Rover Sport and even bikes are now coming up alongside me and having a go! I am definitely achieving significantly higher speeds on the same stretches of road (for example it was only possible to accelerate to 150kph on a certain stretch before needing to slow down and I'm now hitting 170). The whole engine feels MUCH MUCH more like a naturally aspirated car. The response time for the turbo has been cut in half, allowing for quick impromptu maneuvers where before you wouldn't have had boost in time.
If APR is getting 310HP on the stock pipe, imagine Stage 2.. with an IC! I have never put anything other than regular 95RON in the car, think I'll try 100 on my next fill
