We finally had everything ready and took the car/head to the dyno today(4.4.2013). After an interesting drive on public roads we arrived and installed some "jumbo" sized wheels on it so that it wouldn't bottom out on the dyno. A few pulls later and with some small ignition adjustments we ended up with a maximum power of 75.5kW or about 103hp.
This was a bit lower than our target, but based on the power curve and our calculations it seems like something about the intake isn't working properly. The areas where the intake should be ramming seem to be completely missing. The exhaust does seem to be ramming nicely though. Something about the combination of 1.5:1 rockers, a 320deg camshaft and our intake manifold isn't working correctly. We will investigate the intake issue and hopefully find and fix the problem.
On a positive note, there were no real issues with the head. It held together nicely and the cooling system and everything seemed to be working like it should.
Below is a picture of the car on the dyno and the power curve.
The testing of the head is progressing nicely. We had some fun with the Mini in the snow and then also took it out on the road to get some mapping done with more throttle. There was quite a lot of traffic though so we will do some more mapping soon.
We also finally managed to fix the 3D-printing issues we were having and finished the second(and largest) part of the intake manifold. Now there is just the plenum left which should be quite easy to print.
While we were waiting for the weather to improve we took the head off the engine to see how everything looked after the running we've done. The valves seats had leaked slightly so we did some machining on the valves which should fix the problem.
There has been some confusion about the split center exhaust port so to clarify things below are a few pictures of it so you can better understand how we achieved 8 ports. We designed the head from the start with the split center port. Countless hours were spent optimizing the port so that the splitter plate wouldn't restrict the flow. The cross sectional area on each side of the splitter plate is larger than at the port opening and the splitter plate blends naturally into the overall port shape.
After quickly putting everything together we managed to start the engine today (January 18th 2013). It took a few tries to get the settings close enough for it to start, but eventually it came to life. Because the car is indoors and we don't have proper ventilation we weren't able to test it further. Everything seemed to work though, no strange noises and no leaks.
The weather is supposed to get a bit warmer soon, so we will route the exhaust outside and do some more mapping. Videos coming soon... edit: now
28.1 update: A wire from an ignition module had come loose which caused some issues and took quite a while to fully fix. During the troubleshooting process we had the exhaust off, so here is a short video of when we started it with open headers. We are currently working on putting an alternator on it and then it is time to do some road testing!
It's starting to look like we'll actually get the head finished and tested soon! Winter is in full force here in southern Finland, but that is not going to stop us from testing the head in our retired race mini. Mechanically it's fairly complete, there are some plugs that need to be put in and a few threads that need to be made, but other than that it's pretty much done. It also turns out that getting the shorter head studs we need for the head is a bit problematic, we actually had to order them from a machine shop.
There is a lot of wiring left and we still need to sort out the 3D printing. We have received the parts we need to hopefully fix the problems with the 3D printer. Below are 2 rendered pictures of what the complete intake manifold is going to look like. It features equal length runners and was designed to be as compact as possible to fit inside the engine compartment. Because of its size we have to print it in 3 pieces, the first one can be seen in one of the pictures lower down. At the moment it's designed for use with a Ford Mondeo 1.8 throttle body.
More information and pictures of the collectors can be found here
After a much too long delay we are back on track again with the head. We finally completed some other time-consuming projects so we have a lot more time now to spend on this project.
The final test specs are now also clear. We will be running Autronic fuel injection which we will borrow from another car. We also considered just using a carburetor to potentially save some time, but that would again cause other difficulties, eg. fine-tuning the engine would be more difficult.
The intake manifold will be 3D-printed from plastic, compared to a welded design this gave us more freedom in the design, and also guarantees that all the intake runners have identical lengths. We have also machined the center exhaust adapter so that we get 4 individual exhausts as well as some intake adapters where the injectors will go. We will possibly integrate the injectors in the head in a newer version, the production version will likely also feature a (yet again) improved exhaust design. The valve seats are in the head now and the valves and throttle body are ordered. Everything else will be taken from a retired race head.
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