KiwiBirkin Posted July 8, 2009 Share Posted July 8, 2009 I may have the chance to re-power my Birkin S3 with a 1998 1800 Mazda (Miata)MX motor but dont know if its worth doing my Birkin has been powerd by a 1600xflow with weber 40s and a T9 gearbox since its build date in 1997 and the motor is pretty strong and goes ok with about 100 HP, the Mazda MX5 1800 would be with its standard ECU and 5 speed gearbox. I really interested in comments about going from carbs to injection and apart from the MX5 being a more modern motor what would be the pros & cons off this as I have a lot of interest in people wanting my 1600xflow setup for formula ford racing here in NZ as the motors are getting very hard to get now, it would be a straight swap with no cost to me on getting my motor out and replacing with a MX5 motor installed into my Birkin by the the local Seven builders here in Christchruch NZ who use MX5 motors in all the turnkey cars. I know this seems like a silly Qs as the MX5 motor is more modern but there must be some pros & cons. Cheers Link to comment Share on other sites More sharing options...
xflow7 Posted July 8, 2009 Share Posted July 8, 2009 Most importantly, the xflow on carbs makes it sound like a proper Seven. :jester: :leaving: Link to comment Share on other sites More sharing options...
Croc Posted July 8, 2009 Share Posted July 8, 2009 :iagree: Xflows have a lovely sound to them. Much better than the other shopping trolley engines available. Does a MX5 Miata engine have more power/torque than a xflow? The 6 spd Mazda gearbox that comes with it is a sweetie. Link to comment Share on other sites More sharing options...
KiwiBirkin Posted July 8, 2009 Author Share Posted July 8, 2009 I know the later model MX5 engine the NB is a higher torque engine with about 133hp and its a quite easy to get more hp out of with a simple cam upgrade. Link to comment Share on other sites More sharing options...
scannon Posted July 8, 2009 Share Posted July 8, 2009 I may be a bit biased but I say go for it. You may lose the sound but you gain modern fuel injection, some hp, a really sweet transmission (go for the 5 speed, its a better transmission and you don't need the close ratio 6 speeds or you will be too busy shifting to enjoy the car). Parts are easy to find and it will be many years before parts become scarce. You also get an engine that doesn't leak, doesn't need valve adjustments and has a large aftermarket of speed equipment. I f you can talk them into it, get a model year 2000 engine. There was a major change to the intake manifold and inlet passages that lets it make around 140 hp. The 2000 engine does have solid lifters so you have to check them every 50,000 miles. I'm running that engine in my Caterham and with a turbo, big injectors, a stand alone ecu and no internal mods it is putting out 301 wrhp and 260 lb ft torque. Skip Link to comment Share on other sites More sharing options...
bball7754 Posted July 8, 2009 Share Posted July 8, 2009 Any issues with the height of the engine, and/or width of the transmission? Skip - I thought the trans. was a tight fit in your SV? Steve Link to comment Share on other sites More sharing options...
scannon Posted July 8, 2009 Share Posted July 8, 2009 Any issues with the height of the engine, and/or width of the transmission? Skip - I thought the trans. was a tight fit in your SV? Steve The engine clears the bonnet and nose cone nicely. I do have only 2.5" of clearance under the sump. The transmission is a tight fit, Miata transmissions have a large boss on the tail shaft for the power plant frame (PPF). The PPF is a large ali channel that connects the transmission to the diff. It also serves as the 3rd mount for the engine and transmission. I had to cut this off and make a mount to match the Caterham cross member. This page shows three tail shaft housings, the one I butchered to see if I could make it fit, a stock one and the finished product. There are also pictures of the motor mounts, fit of the engine under the bonnet and a top view showing how much of the trans goes into the tunnel on the same page. Skip Link to comment Share on other sites More sharing options...
Ian7 Posted July 8, 2009 Share Posted July 8, 2009 kiwi: please send PM re: demand for x-flow's; I have one, and I'm thinking of upgrading as well... thx Link to comment Share on other sites More sharing options...
lowflyer Posted July 9, 2009 Share Posted July 9, 2009 Like most things in life, you can make arguements for both sides of the question. The Miata is a bulletproof engine, which can be upgraded for more power, the 5 speed is a plus, and the parts are easy to find. Downside, cost of buying new drivetrain (even if purchased used), hassle of fabbing up motor mounts, rad hoses, throttle cables, etc. Not to mention the wiring issues of converting to a computer controlled engine. The crossflow is a great engine, and if you're only getting 100 hp out of yours there is something wrong. A good Formula Ford engine with a stock cam, and single two barrel Weber 32/36 will get around 108-112 hp. Add in a good head clean-up, a cam and a set of Weber 40's and you should be getting around 130-140. Parts are getting to be a problem, but still available in Jolly Old England. No costs for a new power train, no conversion headaches, and the simplicity of a wooden mallet. It all depends on your desires, and your budget but either one should provide lots of good fun. Link to comment Share on other sites More sharing options...
scannon Posted July 9, 2009 Share Posted July 9, 2009 Downside, cost of buying new drivetrain (even if purchased used), hassle of fabbing up motor mounts, rad hoses, throttle cables, etc. Not to mention the wiring issues of converting to a computer controlled engine. From his original post, it appears the swap will cost him nothing and he won't have to do the work either. it would be a straight swap with no cost to me on getting my motor out and replacing with a MX5 motor installed into my Birkin by the the local Seven builders here in Christchruch NZ who use MX5 motors in all the turnkey cars. It also sounds like the local Seven builders have a lot of experience doing this so it should be a trouble free car as far as the engine and transmission are concerned. If it were me, it would be a no brainer - here's the keys, have at it. Skip Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now