In keeping with this "exhausting" issue of VW Trends Magazine, we decided to take some of the more commonly available exhaust systems, and put them to the test. We wanted to see how much they actually help the VW air-cooled engine breathe better, thereby increasing horsepower and torque. We made a call to The Real Source, in Effingham, IL, and ordered the most commonly available aftermarket exhausts, and ran them on Geoff Hart's Stuska engine dyno, in Fountain Valley, CA. The "mule motor" that we used was a brand new, bone-stock, Mexican -built, 1600 cc, dual port engine, from Btlmex, in Nogales, AZ. The first thing we did, to establish a baseline, was to fire up the engine, and run it in (This was a brand new engine). Right away, we realized that the factory doesn't set the valves on a brand new engine; they leave the valves un-adjusted, so that during storage there won't be any pressure on the valve springs. After a quick cool-down and adjustment, and break-in of the engine, we are ready to see what, if any, gains could be made by the simple addition of an aftermarket exhaust.

So, we took the bone-stock engine, popped it on the dyno, and fired it up. The stock Mexican 1600's come equipped with a Bocar 34 PICT-3 carb, with a 117 main jet and a 90 air. We took the new engine to 5,000 R.P.M., a level we still felt somewhat safe with, considering that the engine came with a cast crankshaft and flywheel, and was not balanced to within a close tolerance from the factory.

Dyno run #1

R.P.M Lbs. Horsepower Torque
2500 16.8 42 88.23
3000 16.2 48.6 85.08
3500 15.2 53.2 79.83
4000 14.2 56.8 67.22
4500 12.8 57.6 67.22
5000 10.2 51 53.57

Not too bad for a fresh engine, huh? I guess those folks at the Puebla plant know what they are doing. However, to satisfy our "need for speed", we installed a Europsport single tip exhaust, by Mid-America/The Real Source, and tried it again. This exhaust is designed to run the tips out the stock location in a Sedan rear apron, so if clearance is a problem with a single quiet pack or dual mufflers, such as on a radically lowered car, or you don't want to fill in holes for the exhaust cutouts on your apron, this could be the way to go.

--------------------------------------------------------------------------------

Dyno Run #2

R.P.M. Lbs. Horsepower Torque
2500 17.2 43 90.33
3000 16.6 48.9 87.18
3500 15.6 54.6 81.93
4000 15 60 78.78
4500 13.6 61.2 71.42
5000 11.2 56 58.82

Hey, not bad for an add-on, between 4 and 5 horsepower from 4000 R.P.M. to our self-imposed redline of 5000. Geoff, however, felt that with the more free flowing exhaust the engine was running lean, and a quick plug check confirmed this. He exchanged the 117 main jet for a 125, and we tried it again.

--------------------------------------------------------------------------------

Dyno Run #3

R.P.M. Lbs. Horsepower Torque
2500 17.2 43 90.33
3000 16.8 50.4 88.23
3500 16.4 57.4 86.13
4000 15.2 60.8 79.83
4500 13.8 62.1 72.47
5000 11.8 59 61.97

Wow, a simple 3 dollar jet change netted us a solid 3 ponies at 5000 R.P.M. Guess Geoff was right about the engine running lean ! A quick plug check confirmed that the engine was, in fact, much "happier' with the fatter main jet, so, with the rest of the more free-flowing exhausts yet to come, we decided to leave it right where it was.

Now, we take off the Euro Sport Single Tip, and install an S&S header, with a single quiet-pack muffler. This exhaust was one of the best-fitting, with almost no bending and tweeking required to fit it on the engine.

--------------------------------------------------------------------------------

Dyno Run # 4

R.P.M. Lbs. Horsepower Torque
2500 18 45 94.54
3000 16.9 50.70 88.76
3500 16.4 57.40 86.13
4000 15.6 62.40 81.93
4500 14.2 63.90 74.58
5000 12 60 63.02

Seems like the engine responded well to the S&S system. It was probably a better match, however slight, in back pressure for the stock intake and carb system. At 3500 R.P.M. the exhausts were identical in Horsepower and Torque readings, but on the top end, the S&S edged out the Tri-Mil by 1 horsepower and about 1 lb.-ft. or torque at 5000 R.P.M.

Now, we simply unbolted the single muffler, and, using Performance Technology's "Burn-proof" collector gasket, installed the S&S dual muffler onto the header, since the single and dual header are identical.

--------------------------------------------------------------------------------

Dyno Run # 5

R.P.M. Lbs Horsepower Torque
2500 17.6 44 92.44
3000 16.8 50.40 88.23
3500 16.6 58.10 87.18
4000 15.8 63.20 73.53
4500 14 63 73.53
5000 12 60 63.02
Well, it seems that the bone-stock engine liked the back pressure of the single quiet pack a little better. We actually lost a tiny bit of horsepower, at 4000 and 4500 R.P.M., with an identical reading at 5000 R.P.M., but with a gain of a little over 1/2 horsepower at 3500 R.P.M.. Okay, on we go-

Now we install The BUGPACK header system, first, with a single quiet pack muffler. This system fit with ease, as well.

--------------------------------------------------------------------------------

Dyno Run #6

R.P.M. Lbs. Horsepower Torque
2500 17.8 44.50 93.49
3000 17 51 89.28
3500 16.6 58.10 87.18
4000 15.6 62.40 81.93
4500 13.7 61.65 71.95
5000 11.6 58 60.92

Well, it seems that our stock 1600 dual port likes the BUGPACK exhaust, as well. We kept up, to a close margin, to the S&S unit, only seeing a noticeable drop at 5000 R.P.M. This could be in the way the exhaust header is made, the muffler, what's inside the muffler for packing, and a number of other things. All in all, it's a close race.

One thing we tried to do was test the two commonly available 4-Tip mufflers, but, finding that we were going to have to modify both them to even get them to fit, and wanting to keep the tests all on the same day, with ambient air temperatures and relative humidity as close as possible, we gave up on testing them. We may, if we have some more time, bend them and tweek them and get them to fit, at a later date.

Now we simply exchange the BUGPACK single muffler for a dual muffler setup, also by BUGPACK. Since the headers are, once again, identical, three bolts and a new Perf Tech collector gasket, and we're ready to torture this 1600 some more.

--------------------------------------------------------------------------------

Dyno Run # 7

R.P.M. Lbs. Horsepower Torque
2500 17.2 43 90.33
3000 17 51 89.28
3500 16.6 58.10 87.18
4000 15.8 63.20 82.98
4500 14.4 64.80 75.63
5000 12.2 61 64.01

Well, we lost a bit on the lower end, but gained 3 ponies at 5000 R.P.M. This exhaust, with the dual mufflers, was the highest horsepower at 5000 R.P.M. of all the exhausts tested, but the other ones were very, very close. We had one other exhaust to try, and that was the same BUGPACK header, but this time with the hideaway muffler, for those folks that want the ground clearance that a single or dual quiet pack doesn't offer, and want the noise of a remote muffler, instead of the exhaust note that the Dual-tip or 4 tip exhausts provide. Once again since the BUGPACK header was identical, all we had to do was yank the dual muffler off and install the hideaway muffler, and run the engine one more time ( PLEASE hold together, engine, I promise this is the last one !)

--------------------------------------------------------------------------------

Dyno Run # 8

R.P.M. Lbs. Horsepower Torque
2500 17.6 44 92.44
3000 17.2 51.60 90.33
3500 16.8 58.80 88.23
4000 15.8 63.20 82.98
4500 14.2 63.90 74.58
5000 11.6 58 60.92

Wow- this one beat the BUGPACK single muffler across the board, with identical horsepower readings at 5000 R.P.M. It even came close to the BUGPACK dual muffler exhaust.

As you can see, the exhausts were very close in horsepower and torque readings. From here, you will have to check the price and availability of these exhausts, and decide which one fits your application, and also your budget. Special Thanks To The Real Source, for letting us take brand new exhaust systems right out of the box, and immediately burn the paint off of them. Also, thanks to Geoff Hart for the use of his dyno and his time, helping us with the shootout. Okay, that's enough, I'm "exhausted" !

SOURCE BOX

The Real Source
One Mid America Place
P.O. Box 1248
Effingham, IL, 62410
1-800-LUV-BUGG
http://www.800luvbugg.com

Geoff Hart's Racing Engines & Dyno Service
Fountain Valley, CA.
(714) 222-0044

Performance Technology
1631 Placentia, Unit "M"
Placentia, CA., 92806
(714) 526-0533
fax: (714) 526-1366