Alex Vendler

I've seen that part. It's pretty, and well made too. Only issue is that is triples the length of the intake runners. It also negates the bi-length runners that come on a 'Busa to spread out the torque. Still a nice solution.

Updates!!! Take a look because the airbox/filter assembly we are prototyping will work on any 'Busa powered project that has hood clearance issues. Yes we will sell them separately!! http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1704/project-miatabusa-part-43--the-intake-manifold.aspx

If you keep the stock pan with it's vee shape I don't think you will have any trouble. The real advantage of a dry sump is that it allows you to run a nearly flat plate where the pan used to go. Better clearance.

We are taking power off the gear reduced countershaft in the 'Busa engine not the crankshaft! It's reduced at a ratio of .625 so 12000 crank rpm is reduced to 7500 clutch rpm. This also means that the stock Miata rear end gear will yield a top speed within a usable range. This also multiplies the torque. Take another look at this article about the rig here: http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1519/project-miatabusa-part-1-what-the-hell-we-are-thinking.aspx

Thanks for the info. Looks like it's about 100lbs from flywheel to driveshaft. Subtract about 35lbs for all the stuff you don't need with the Miatabusa setup and it's a 65lb gain. Not too bad since reverse gear is part of the deal. Oh, and a clutch that is meant for a car.

Please do weigh it and publish what you find here. We'll be doing it again later using a very accurate scale but it's nice to get an idea in advance.

Don't forget about all the parts that get removed using our setup. The full clutch, slave cylinder, transmission gears and shafts, shift drum and forks, shift leaver and linkage, driveshaft adaptor, and about 3 feet of driveshaft are all gone. The Miata trans is in an aluminum case with an integral bellhousing and it's not that heavy. We will be weighing it during the next part of our build and will publish hard numbers. The de-tranny'ed 'Busa engine weighs 135lbs ready to run. That's been weighed and documented. Also, while are adding a bit of weight, it's at the lowest point on the car and in the center of the car as well. A cheap, common trans that has reverse gear and will last 100k miles and is worth a bit of weight penalty.

I would say you should get 150-160 rwhp and 100 ft/lbs of torque at the least. The stock exhaust is far from optimized and since the ECU is tuned for it you are probably running lean overall. There is only one way to find out and that's to test it.

It looks like you have a bit of a tuning issue. It looks like you are not getting all your power. What kind of airbox are you running? If it's not stock, a power commander will really make a difference by optimizing the mixture. As a point of reference, I have a race car powered by a 2007 Honda CBR1000RR engine and it's getting 142hp at the rear wheels. Stock header, stock intake. Your 'Busa can do better I bet.

Hey there- We just stumbled across this thread and I thought I would address a couple of issues posted here. The potential to run our setup in a Seven is very exciting to us indeed. For starters the weight if the car trans is not that significant since we are removing and discarding the bike trans and clutch completely and that stuff if heavy. The net added weight is less than 50lbs.. Less if one is going to run an external reverser box on their BEC. We plan on using the lightest flywheel available for the Miata and while it will be a bit heavier than the rotating assembly of the bike the weight will go to good use by making the car easier to drive in traffic. Also, the car flywheel will actually greatly reduce shock to the bike crank by acting as an insulator between the transmission and the engine. Lastly, while sequential shifting is great, bike transmissions in cars wear way too fast and start popping out of gear and burning up shift forks in short order. Undercutting the gears in bike tranny for use in a car only delays the inevitable. Another huge benefit of the Miatabusa setup is the separation of the engine and transmission oil. We expect the bike engine to last much longer now that it's oil will be free of pollution like gear and clutch shavings. Also, bike clutches heat up the oil significantly. Stay tuned as we progress on the project and please post any of your questions or comments here.