Transaxle for Mazda 12a
I'm considering building a CSR with a Mazda 12a powerplant. What transaxles are used in this class and are there specific ones used with the Mazdas?
Thank you.
jstinehelfer
Unregistered User
(10/17/01 5:33 pm)
Transaxle for Mazda 12A
Most Mazda csr's are running the Hewland Mark 9 with Mark 5 gears. This setup will hold together if it is carefully setup and not abused excessively. I use an 8:31 R&P as it seems to give better matches for the gear ratios for the big tracks like Mid-Ohio and Elkhart.
I magnaflux the lower three gears every two or three races and change them after five races. I expect to lose one or two gears a season. I find Craig Taylor of Taylor gears a wealth of knowledge.
Ben Beasley
Unregistered User
(10/19/01 7:36 am)
Mazda C S/R
I have Adapters Mazda/MK-9,MK-5,VW Case,and other parts that may be helpful .If I can be any help give me a call (440) 357-6644
MazdaNut
Unregistered User
(10/19/01 6:41 pm)
Hewland
I see on the Hewland web site that the Mk9 with Mk5 gears is only rated at 180 ft. lbs. of torque, max. I thought that a properly built 12a could produce around 250 hp and 220-230 ft. lb. of torque. Is this the reason for the gear wear on your Hewland?
Thank you very much for the information.
jstinehelfer
Unregistered User
(10/20/01 9:51 am)
Hewland
A very good Mazda 12A prepared to GT3 spec and choked as required for CSR produces 240 + - about 3 hp. You can play games with fuel, ignition and electric water pumps etc and maybe push 250. Torque will be in the 150 range. The Mazda is a wonderful motor for CSR.
Very reliable, very forgiving if you miss a shift. Ben Beasley make all the parts you need at a fair price to hook up to a 12A. Mazda comp is also great supporters of SCCA racing. Competition is tough however ...we may be few but we are all serious racers.
Jstinehelfer
Ben Beasley
Unregistered User
(10/22/01 9:28 am)
Mazda Engine
Hey ,Mazdanut will you sell me that engine ? 250 HP & 230 Ft/lbs torque ? With 34mm Chokes I'm at 235HP & 150 ft/lbs. torque.I'll take 2, if you can get that kind of power.I think Daryl Drummond has the best motors out there,they have good power,good reliability,and he stands behind his work like no one else in the business.He can be reached at (707) 445-3786 PST.
MazdaNut
Unregistered User
(10/22/01 3:31 pm)
Torque
Ben et all,
It just proves that getting info from just a few sources is not reliable. I figured you guys would have more accurate information, and I am correct.
I never like hearing promised hp and torque numbers before acquiring an engine; it plays on the heart too much!
Thank you for the great information; the project is already in motion and I will keep you posted.
Re: Torque
Hewland has a couple of newer sequential shift boxes available, the NST 5 speed rated at 180 ftlb., and the FTR 6 speed rated at 240 ftlb. They are pricey, the FTR coming in at over $6k if I did the currency exchange correctly. Anyone have experience with these yet?
Steve www.hewland-engineering.co.uk
MazdaNut
Unregistered User
(10/25/01 9:12 am)
Torque/rpm
Gentlemen,
A few questions. I have been talking with several engine builders and have heard some interesting power quotes. I am assuming that the restriction is still 34 mm on the venturies. Is 10,000-11,000 a realistic figure for rpm on a engine built to GT-3 specs?
In addition, what reliability have you experienced with the engine? Do you think that the SCCA will ever make concessions to allow the 13b in this class, especially if they restrict it down to the same standards (or hp levels) of the other engines?
How about fuel injection? It would seem that this class is similar to DSR in its unrestricted nature. You would think that they would move forward with their rules concerning engines, based on the fact that as time goes by, newer engines must be given consideration.
Also, I have heard various weight claims of the engine. Any ideas?
Also, I have spoken with Hewland about their new FTR- it is JUST getting into production- the first units are already committed to by BMW and F3 builders. Don't look for anything on this side of the pond before March/April 2002.
Thank you for your input. While the CSR class may be low in numbers, it is appealing becuase of its increased weight minimumsand potential to build competitive cars.
Thanks,
MazdaNut
Ben Beasley
Unregistered User
(10/25/01 11:17 am)
Mazda Eng. Specs.
My RPM Limit is generally 9600RPM ,if I in a real competitive situation I'll put the 9800 rev chip in the MSD.I wouldn't want to take it to 10,000 . On a regular bassis taking it to 10,000 will shorten it's life and rebuild interval.Going to 11,000 will be expensive and frustraiting,you probably won't make qualifing let alone the race.The Mazda has good mid-range HP ,with proper gearing there is no reason to rev that high.I don't think the 13B should be approved in a detuned state or any state.It goes against the philosophy of pure racecars ,non spec. ,and few rules ,which I beleive C & D S/R to be. Having large displacement spec type engines creates a big torque disparities when they have similuar HP.If you can't afford a good quality race motor,you probably can't afford fuel injection.There doesn't seem to be an abundance of real good quality race engines being bought for C S/R:Toyota , Mazda ,Honda ,VW(has FI),2 stroke ect..If fuel injection where aloud it would create a bigger disparity between the haves and have nots,this in a class that is already fragile is probably not a good thing.If someone else had it I would probably get it ,especially if hes got an RT-41,but I'd Rather not spend what would probably be more than $3000-$4000.A complete 12A weighs @ 250lbs. Not lite.
Jstinehelfer
Unregistered User
(10/25/01 8:35 pm)
Torque/rpm
Ben's numbers are right on. Peak hp is usually around 9400 but the engines pull very nicely from about 7000 rpm on with nice flat torque curves. This makes them very drivable. I expect to get between 20 and 25 hours and usually shift at 9300 and then wind out to 9600 if I need to to minimze shifts for most races. The Runoff and the Sprints are pedal to the metal to 9800(unless it rains or snows). Several people have used sequential shifters in CSR with reasonable success. Remember though you are trying to save time from a 250 msec shift and you might look elseware for improved times to get started.
Jim
MazdaNut
Unregistered User
(10/26/01 7:53 am)
Sequential shift
Really, the real reason for the sequential shift is ease of set-up and the ability to use a simple cable for shift linkage. Although it is more expensive, sequential shifters are more appealing to racers who want the most 'morern' tricks on their cars.
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