Headers for my MG Midget

On a system that has a muffler, one will not see much benefit of equal length tubes though it is still a little bit. Collector diameter and length has a major effect on power.

I made up a set of headers for my 88 Beretta GT. Made one side 28” and the other side 32” with a 3” collector feeding a modified cat and onwards to the muffler and out. Really woke up the 2.8 as it dropped the back pressure by 4# at 5500 rpm.
I was fortunate to have a second engine on a stand to mock up the engine compartment. Using u-bends and lots of cutting and fitting. I did purchase tube connectors to help in the welding. Once done, I had them coated inside and out with Jet Hot, otherwise the tubing would of rusted out in a few very short years.
Pierre
 
To avoid having to replace the rear axle you have to pretty much stay under 100 hp. The stock 3 TC is around 75 hp. If the axle shafts break on me then I will go to race axle shafts which I understand are good for up 125 hp or a little more. There is also a modification that you can do to the stock axles that helps with preventing breaks. It is called growlerizing the axle named after an man down in OZ who first spread the word on the web. I think that I have a thread about that.

No EFI for me. I am going to replace the stock smog carb with a Weber 32/36. It is almost a bolt on replacement. There are excellent reviews from the people that have gone the 32/36 route. The necessary jetting changes are available online. I know people who have gone the EFI route. It requires major surgery to the passenger side foot well to fit. Then you have to fiddle with the programming to get it right. No thanks.

This car will not be a daily driver. It will see occasional use on nice sunny days.

I'll probably order the stuff for the headers tomorrow. Going to think about it over night just to make sure I don't decide to change something.
 
The Weber 32/36 (I think that's a DGAV) has superior street manners and is a very driveable carb. It was designed by glue-huffing stooges, but they sure do the job. I've set up a couple of them on the 1.3 Suzukis and ran one on mine for a long time. The little 1.3s would wind out early, like 5500 on any cam because they were choked on the intake side. Switching to side-drafts would let these motors wind to the sky. So what I'm pointing out is that your larger 1.8 that makes peak HP at 5500 is going to be starving for air at the top end, but the car will be well-behaved with that carb on the street. This is just from my experience, I don't know if you are following a group that has already done this swap and figured the tune out. Like I said, it's fun for me so I keep lobbing questions.
 
There are forums devoted to the 3 TC and to other older toyota engines. A fair number of these engines and the 4 series engines have been swapped into a midget. I even found a website about swapping these engines into a midget that I followed to a certain extent. That site mentioned using dual webers and what was required to cut up the passenger foot well to make them fit. You can buy a manifold for a single weber side draft that fits without surgery. I saw one on I think Ebay but they were asking way more than I was willing to spend. I also thought about using 2 SU carbs off the datsun roadsters and 240z's. I would have to make the manifold and then there was the fit issue. So the 32/36 is the best carb for my intended usage. New ones can be had for a little of $200. Saw a used one for around $80. Haven't really looked much for a used 32/36.
 
I've been a bit busy, so i just seen this thread. Cool project, there is something about those british convertibles. I've had good luck with using a stainless header of a Honda, i'm not sure was it B series engine of D, it was an aftermarket stainless long tube header, i cut off the flange, rotated the tubes and welded them to a new steel flange that i made, i also helped a friend convert some old boat header into a turbo manifold. My advice is find a cheap but good quality header and just change the flange for the engine. About the rear axle, don't even mess with using the stock axle if it breaks, get a ford 8.8", narrow it and weld the flange of the original. Re drill the flanges for 4 bolt pattern and never worry about it.
 
The 32/36 DGV family will flow enough air for about 120 horsepower. Most problems with that carb come from the crappy aftermarket manifolds.


As pulling axles and ringing them was an evening SCCA tradition for a long long time. What pray tell is this Growlerizing?
 
Ordered the tubing. Will have it sometime next week.
 
I see someone read Caroll Snith's books on stress riser relief.
 
Started on the headers today. First up was to make a fixture for accurately cutting the bends at precise angles. I have two to make. One for 1 7/8" bends and one for 1 3/8" bends. Made the 1 7/8" fixture today. Here is the only picture I took of making it. I'll take a picture of the finished fixture tomorrow.

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Next I bent some stiff fencing wire to the curve of the 1 3/8 bends. This will get used to figure out how high the bends need to be above the collector to line up with the exhaust ports and also to determine where the bends coming off of the engine need to be cut.

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Next I used the 1 7/8 fixture to mark the 1 7/8 bend to get a 90 degree cut. I used a zip tie to draw the cut line all the way around the bend. Forgot to take a picture of this. I will take some tomorrow. Made the cut and with a little persuasion with a vise and hammer was able to fit the 1 1/78 90 into the collector. Here is the set up to tack weld the two together. I used wedges to get everything straight. The tube was 1 7/8 OD and the collector was 2" OD at one end and 1 5/8" at the other.

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Next up was cut the slip joint tubes to length and tack them together.

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The slip joint tubes fit into the top of the collector with an ID that matches the OD on the 1 3/8 tubes. Makes for easier fitting of the header tubes into the collector. I almost tack welded the slip joint tubes to the collector. I am very glad that I decided to do a test fit of the collector first. Turns out that the collector has to be at a slight angle for the number 4 tube to clear the steering shaft and for the 1 7/8 tube to fit through the hole between the frame rails. I'll get that dialed in tomorrow. I also discovered that I need to shorten the 1 7/8 tube by 2" or so.
 
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