Homebuilt cheapie 2.25" I.D. exhaust

[clbanman]

The exhaust on my car was falling apart and I am way too cheap to pay what the local jobbers were asking for replacement exhaust.   I'm a bad packrat, and had some 2.25" I.D. tubing that had been thrown out at work and I couldn't resist taking it home.  Always had exhaust in the plans for this tubing so now was the time.  I used the original "bowl" piece that mounts to the manifold, and cut off the exhaust pipe with a zip disc.   I cut far enough up to give about a 2" I.D. opening and then welded a section of the tubing on.  Used a template to keep the origina distance and angle to the top of the tube to ensure it wouldn't hit the floorboards.   Welding isn't pretty, but I finally got it on and together today.  Now have 2.25" I.D back to the rear axle, then 2" I.D. over the rear axle and a 2" turbo muffler.   

[8v-of-fury]

DUDE yes! whats so crappy about it? that's frigging amazing! I wish to do the same on my Mk1 N/a. The opening of the exhaust on the manifold is like 2.5" so you can just as easily add a very free flowing exhaust to a toilet bowl system. Not only that but the exhaust runners on the N/a manifold are one of the best in that the fact the runners are mostly the same length. You my good SIR Have created a masterpiece! I salute you. Want to make one for a Mk1? lol

[theman53]

exactly what I did to my 84 NA before I sold it. I took my foredom and ground away on the inside of that to match the pipe diameter after I was done, but other than that it looks just like mine. Great job. If it works like mine did then you will be able to pour a little more fuel to it if you want to.

[rabbitman]

Wow, that is waaay better than stock!

I always heard that the toilet bowl style was worse than the 4-2-1 on older vw's, but lately I've noticed the manifold looks very good the problem is just that it necks down so small in the downpipe and stays so small.

Looks like you'll be able to run cooler egt's or get more power .

[8v-of-fury]

.....is just that it necks down so small in the downpipe and stays so small.

Exactly! ane because he opened it wide... it is now the best exhaust system you could put on an N/a! YESSS! Way to go buddy, nice job.

p.s I was serious about making me one lol

[clbanman]

Well, I have no baseline numbers to compare it to, and the seat of the pants thing isn't remotely close to being accurate, especially since with various holes in the exhaust over the last month or two I've been babying it to keep from attracting the wrong attention;  but I like how it feels and sounds.   Mind you with it being quieter I'm keeping the pedal closer to the floor (where it belongs), but in the strictly subjective "keeping up with traffic" test, it passed.   Of coarse, with a 1.6NA with 500,000+ km, keeping up with traffic often means the tail-lights don't dim as quickly.

[Rabbit TD]

That looks fine to me, I was gonna try that but I got lazy and just had a place bend me a 2 in. section over the axel on the Rabbit and I just used the 2 in. front pipe also.

[clbanman]

Just to update.  If you have a NA,  do this immediately.  This woke the car up like I never thought it could.  Mind you I did pull out the resonator or whatever muffler deal is at the rear of the straight section ahead of the axle and I have no idea how restrictive that was, so I can't say for sure it's all due to diameter change.   As stated previously, I don't have baseline numbers, but I drive home the exact same route most days, and I have a short (1.5 km) run along the 401 that I do.  Ramp onto the 401, give her, and slight continuous uphill grade to the next exit (enough to keep the smoker working the whole way).  I have never been able to get the car up to more than 105 kph on this stretch before.  Hit 120 today.  I haven't touched anything else on the car.  It has 500,000+km on it.  I had no problems keeping up with traffic, even had a couple stretches of 4 lane road where from one traffic light to another I had 7 or 8 cars behind me and I didn't get passed by a single one.  That has absolutely never happened before when driving this car.  Mind you with the workout the go pedal is getting, I expect my fuel mileage to drop, but we'll see.  

EDIT:I did the job in two steps.  My OEM pipe rotted out above the rear axle, so I built a 2". O.D. pipe to run from the resonator and run over the axle to a Cherry Bomb Turbo (from Part Source - same as Canadian Tire carries) with a 2" inlet and outlet.   This alone didn't make much of a difference until I put in the 2.25" I.D. from the manifold back to the 2" section I had previously made.  The second step eliminated the resonator, so it is possible that part of the improvement was from eliminating that restriction alone.   If I drive like I did before the mod, I can save a little bit of fuel, but to be honest, the ability to keep up with the majority of traffic as opposed to previously is so nice that I beat on the sucker much more than I did before, so my fuel mileage has dropped.  My last 2 tanks, using winter fuel and "spirited driving" (for a N/A) netted me 6.15l/100km or 38.22 mpg U.S. or 45.9 mpg imperial.   

[maxfax]

Nice work indeed!!!  Definitely looks much better than the abortion under my car...   
OPening up that toilet bowl is the best thing you could do!!  Comparing something like you have to the dual outlet manifold my butt dyno could tell no difference..

 For curiosity's sake, keep an eye on your temperature..  Especially over hills and mountains... I know the egt's have to be lower, but I also noticed my coolant temp being lower over mountains and such..