Mating a Miata transmission to the Busa Engine

[scannon]

In this article they are putting the Busa engine in a Miata but the adapter parts are going to be marketed and might be an alternate solution for BECs.

 

http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1519/project-miatabusa-part-1-what-the-hell-we-are-thinking.aspx

 

 

BTW, the reverse gear on a Miata transmission is synchronized. The only other car I know of that does that is the Lamborghini.

Edited March 31, 2010 by scannon

[Spaz]

Very cool!

[Hank]

Very interesting. I can't wait for the outcome.

 

However, no matter what you do to a Miata... you'll always look gay in it.

[BMW RACER]

In this article they are putting the Busa engine in a Miata but the adapter parts are going to be marketed and might be an alternate solution for BECs.

 

http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1519/project-miatabusa-part-1-what-the-hell-we-are-thinking.aspx

 

 

BTW, the reverse gear on a Miata transmission is synchronized. The only other car I know of that does that is the Lamborghini.

 

BMW's have had synchro reverse since 1984.......... Love it!!

[scannon]

However, no matter what you do to a Miata... you'll always look gay in it.

Some of us are secure enough in our manhood to neither care nor worry about that. Especially not when it would mean not owning one of the best driving cars to come along.

 

Others just keep harping on it.

[MHKflyer52]

Some of us are secure enough in our manhood to neither care nor worry about that. Especially not when it would mean not owning one of the best driving cars to come along.

 

Others just keep harping on it.

 

I have to agree that the Miata is one of the best sports cars to come along and in the years to come will be looked at as a great sports car that it is.

The Miata is the best selling sports car ever made and more of them have been sold since 1989 than all sports cars combined since it first came out.

Yes I am bias as I have one (1996 Black and Tan) and I drive it more that I drive my Replica 7 or my Porsche 914-6 or my MG Midget any of the other cars that I have and my wife will tell you I am in no way gay. I just figure that they have never driven a Miata or they would not think it is a gay car at all or they are just not sure of themselves. :cooldude:

[Spaz]

[TLRracer]

Probably the single most important article for anyone who ever considered a bike-engined car but was worried about the connected problems inherent with that mix. With the 'busa engine and a Miata transmission any 7 could be bike-engined with no reverse issues whatsoever - the reason bike-engined 7's blow the bike's tranny is because of the load on it from a heavier car - the problem - she is a solvedd!

 

This article answers soooo many questions for me:)

I emailed the magazine and the guy doing this project is coming back from Germany in 3 weeks and will be back on ze case:)

 

jd

[Tralfaz]

Bound to be cheaper than the Hartley H2( http://www.h1v8.com/H2.html ), but 'perhaps' not as well engineered

[erioshi]

Color me a skeptic. I think it can be made to work, but I suspect you will loose some of the more important (at least to me) bike engine characteristics.

 

1) This adds back all the weight of a car transmission

2) It adds a heavy automotive flywheel & clutch (plus the rest of the drive line) working against the very lightweight bike engine internals .. that could lead to some very serious engine shock

3) This solution replaces the very fast sequential bike transmission (suitable for flappy-paddles) gear shifts with a fairly decent shifting car transmissions with typical car shift throws & gates.

 

There are two possible strong upsides, though. Reverse as everyone has already mentioned. But a second, perhaps more useful benefit would be replacing the tightly spaced bike gear ratios with a set of gear ratios more widely spaced and suited for use in a car. I am definitely interested in seeing how the project shakes out.

[pierats]

Seems like a very interesting project. I wonder what the drivetrain losses would be for this setup?

[Spaz]

Part 2 has been posted:

 

http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/1619/project-miatabusa-part-2--the-engine-is-in.aspx

[Alex Vendler]

Color me a skeptic. I think it can be made to work, but I suspect you will loose some of the more important (at least to me) bike engine characteristics.

 

1) This adds back all the weight of a car transmission

2) It adds a heavy automotive flywheel & clutch (plus the rest of the drive line) working against the very lightweight bike engine internals .. that could lead to some very serious engine shock

3) This solution replaces the very fast sequential bike transmission (suitable for flappy-paddles) gear shifts with a fairly decent shifting car transmissions with typical car shift throws & gates.

 

There are two possible strong upsides, though. Reverse as everyone has already mentioned. But a second, perhaps more useful benefit would be replacing the tightly spaced bike gear ratios with a set of gear ratios more widely spaced and suited for use in a car. I am definitely interested in seeing how the project shakes out.

 

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.

[fastg]

Alex, do you have any actual weight number? I spend a lot of time working on bikes and the stuff it light. I just shipped a complete suzuki trans with a shipping weight of 18 pounds. I just has a complete trans and clutch in a cardboard box on my bench, you could easilly pick it up with one hand. compare that to an automotive bellhousing, flywheel, clutch and transmission. I think the differance is a little more than 50 pounds.

 

Graham

[Alex Vendler]

Alex, do you have any actual weight number? I spend a lot of time working on bikes and the stuff it light. I just shipped a complete suzuki trans with a shipping weight of 18 pounds. I just has a complete trans and clutch in a cardboard box on my bench, you could easilly pick it up with one hand. compare that to an automotive bellhousing, flywheel, clutch and transmission. I think the differance is a little more than 50 pounds.

 

Graham

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.

[scannon]

Miata 5 speed transmissions weigh about 85 lb. I have one sitting in my shop that I could weigh if someone wanted exact weight, at least to bathroom scale accuracy. I also have a new clutch and disk from the Mazdaspeed Miata turbo engine I could weigh. Its the same clutch I use in my Caterham.

 

I'm running an 8.5 lb flywheel in both my Miata and Miata powered Caterham. Works well on both cars.

[Alex Vendler]

Miata 5 speed transmissions weigh about 85 lb. I have one sitting in my shop that I could weigh if someone wanted exact weight, at least to bathroom scale accuracy. I also have a new clutch and disk from the Mazdaspeed Miata turbo engine I could weigh. Its the same clutch I use in my Caterham.

 

I'm running an 8.5 lb flywheel in both my Miata and Miata powered Caterham. Works well on both cars.

 

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.

[scannon]

1999 - 2005 Miata 5 speed includes integral bell housing - 84 lb. This one was from a 2000 Miata. I forgot to take the driveshaft yoke out that I use to keep the dirt out and the oil in when installing/removing the transmission so take another 2 lb or so off for that. The oil was drained and the gear lever installed when weighed.

 

I suspect the 1990 -1997 transmissions might be a few lb less as the '99 and up added an additional syncro ring and a 5th - R lock out mechanism.

 

2004 - 2005 Mazdaspeed Miata (factory turbo) pressure plate, disk, throwout bearing, pilot bearing and 6 bolts for flywheel to crankshaft - 14 lb including the boxes that probably weigh less than 1 lb total.

 

Weights taken on my trusty bathroom scale which is usually within a pound against the post office and UPS scales.

[Alex Vendler]

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.

[scannon]

Speaking of clutches, I'm not confident that a clutch designed for a 7,300 RPM fuel cut will be safe at 13,000 RPM. I'd be looking for something that was rated for that level.