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MRSLOTCAR MAZDA 787B Technical Review

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  • MRSLOTCAR MAZDA 787B Technical Review


    A Technical Review

    by Chris Walker

    Well, after a rather long wait the MR.SLOTCAR MAZDA 787B has finally hit the shelves…..was it worth the wait ??...let’s have a look !!

    The car has been designed/produced by Ernie Mossetti (MR.SLOTCAR), and for those unfamiliar, Ernie has been designing and manufacturing race and championship winning chassis for many years covering both 1/32 and 1/24 scales from stamped “flexi” to EDM and laser cut Eurosport and “open” chassis.

    This is his initial launch into the plastic RTR marketplace, and with his successful track record, you would fully imagine that our expectations would be high.

    The initial offering is the Mazda in both “White” kit, and a black test car version, soon to be followed by the “Renown” version. In the works is a line of motors, gears, pods, braid etc. as well as a complete list of service parts.


    I must admit that the 1:1 Mazda is not my favorite car, but this 1/32 version certainly captures the feel of its larger brother/sister. Dimensionally, it is slightly smaller than its 1/32 Mazda competition, but according to the calipers, it is virtually dead on in terms of scale length/wheelbase/width and height. The scale advocates (me included) will be pleased.

    I opened the parts bag on the supplied white kit and all the parts were there, including flexible mirrors, and a rear wing with robust struts and a clever mounting system that slips on over the rear 2 body posts. The mounting bracket allows for some flex in the wing, which should provide a good level of durability, and is dead simple to remove/attach in the event of a more serious offense.

    My one “cosmetic” gripe, and a small one, is the wheel inserts….while the spoke pattern is accurate, the spokes are surrounded by a trim ring that is painted a rather dull aluminum color, and this ring gives a somewhat painted look to the wheels as opposed to the polished aluminum look of the real car.
    Picky I know, and thankfully, easily fixable.

    Overall, the body and bits are nicely molded, fit well, and the rear wing mounting system is a bonus, on these aspects the car compares well with its racing focused competition.

    On to the running gear !!..............

    On removing the body (via three body screws with partial threads to help body float), my first reaction was that this is a well designed/manufactured car, frankly I had expected little else.

    Starting at the front, the guide is secured with a one piece screw/washer, and rotates nearly 90 degrees from center in each direction, which will help eliminate cracked keels and post holes. A small vertical tab is molded between the eyelet holes helping to reduce the possibility of lead wire shorts, and the interface between the guide and chassis is unusually precise, resulting in practically no unwanted motion/wobble in any direction. Very good start!

    Guide lead (center of rear axle to center of guide post) is just short 96 mm, similar to many LMP/Group C cars currently available.

    The front wheels (MRSLOTCAR designed) are lightweight aluminum secured by setscrews, and are a standard 15 x 8 dimension, and will therefore readily accept any tire designed for this size wheel They spin true and with no runout, and have a solid precision fit with the front axle. Both axles are hardened steel with a 53 Rockwell value. While not as hard as true drill blanks, they are likely a touch harder than any other RTR , and will not suffer from any setscrew scoring.
    The axle carriers have holes on the top and bottom, which accept M2 setscrews, making ride height/vertical travel adjustments easy.

    The motor pod (inline endbell drive on the RTR, with sidewinder/anglewinder versions to come), is triangular in shape, is made of glass filled nylon. and is attached by 1 screw on the front, 1 on the back, and 1 on either side, providing a good range of movement to be dialed in depending on your preference. A couple of neat cone shaped springs are available separately, and when placed on either side of the pod provide adjustable torsional rotation.

    On first inspection, the rear uprights appear a tad frail, but a closer look reveals gussets on the inside of each upright. Wide bushing placement, and, the glass filled nylon pod material result in the rear end having a very solid feel, with minimal flex noted at the pinion/crown interface.
    (Initial track tests did not reveal any chatter/wheel hop….. usually indications that the rear end needs some attention, so all appears race ready in this department).
    For those wishing to add additional bracing material, there is plenty of surface area to easily do so.

    The MRSLOTCAR aluminum setscrew rear wheels are also standard 15x 8, and therefore it is easy to utilize your favorite “rubber”. They run on a very good quality 3/32 rear axle, and are supported by 2 very small OD double flanged bronze bushings. The bushings are smooth, and are very close tolerance, a requisite for a smooth running car. However, close tolerance bushings are never too happy when misaligned, so, an initial alignment check and securing of the bushings is always worthwhile. (Like all of us, I believe that my personal desire for my car to be set up correctly far exceeds that of anyone on the assembly line).

    The car comes geared 9/28 and uses MRSLOTCAR designed gears. These are a standard .5 metric pitch, so similar pitch gears from other manufactures can be interchanged. The bronze boss on the crown is milled on both sides to keep weight low, and is thoughtfully drilled/tapped on opposing sides should you wish to use 2 setscrews. The crown on the car tested was very concentric with no run out, and on track gear noise was very minimal indeed.

    A single (wide) bar magnet sits in a pocket just forward of the rear axle and offers competitive downforce for a single magnet car (110 gms). There is however, only 1 cutout position for a magnet, and while there is room on the chassis for tweaker magnets, those wishing to create the ultimate mag missle will have to be creative. The chassis is as stiff or stiffer than anything on the market in terms of longitudinal flex, so those wishing to add magnets will be able to do so (to a point) without fear of dragging the chassis on the track. This solid longitudinal flex attribute is a distinct bonus to no mag racers as well.

    The motor cradle tabs hold the motor in place……….no better or worse than the competition in that, yes, the motor does move somewhat in its cradle. This is an apparently somewhat unavoidable situation for all manufacturers, as the folks on the assembly line are required to install the motors in an easy (read quick) fashion, and therefore generous dimensions are required in this area. ( As a quick aside, this is more pronounced on setups that utilize a hoop circling the endbell where the motor must be initially tilted to have the pinion clear the motor bracket hoop. Without this hoop a motor can be installed completely vertically, and tolerances can be reduced).
    While I have no doubt that the motor will remain in place in all but extreme situations, I know that most enthusiasts will secure the motor using their preferred method.

    The motor is of standard “S” can dimensions, and has been produced to MRSLOTCAR specs.
    Rated at 22K it incorporates a longer than average armature stack (+1.0mil), using 2 additional stack plates. This provides additional torque/brakes, and nets out as a smooth, cool running motor.
    Track tests reveal a smooth power band, with performance more than enough for most applications. It has enough torque to easily pull a lower tooth count crown for those with long straights.

    I have not attached all the body bits yet, but estimate that the car will weigh in at just under 80gms. (with beefier than average bar magnet installed), again, competitive, and all the weight appears to be in the right places.

    So,..How does it go????........

    Well, considering the design elements, and the attention to detail, It performed as expected…….the car has a precise mechanical feel, smooth with no vices, it is fast, forgiving, and a pleasure to drive.
    Despite running on the stock tires, which are not the hot ticket for my track, it was clear that with the right “rubber” this car will be very potent indeed !!

    Will it be competitive ??.....absolutely, Will it rule the roost ?? ……time will tell,…. Tuning expertise and driver ability are the biggest variables in the ultimate success of any car, if you possess these, the car will not disappoint.

    Chris Walker
    Last edited by chrisguyw; 03-31-2011, 03:20 PM. Reason: Title change

  • #2
    Thanks for the review CW. It is a sweet driving car isn't it ... and I am hoping that the build quality at this price point makes the car a big success that will lead to more products from Ernie & Co.!


    • #3
      Thanks for the review... I'm looking forward to receiving mine, just ordered it this morning...


      • #4
        Thanks Chris, great review. I was wondering about this car and you've pretty much answered all my questions.




        • #5
          A very thorough overview with excellent pictures. Thanks Chris. The chassis looks very well thought out. Do you happen to know the wheelbase measurement by any chance?



          • #6
            I have known Ernie for many years and it's always a pleasure to race with him. I certainly wish him the best in his new venture.


            • #7
              Thanks for the review. Spoke to Ernie when he was 1st starting this project. Great guy! Who's shelves are the on as the test car is on my "2010" must have list...Please LMK.


              • #8
                Boy I'm getting old! I met Ernie many years ago and I have emailed him a couple of times when I got into 1/32 plastic cars and found out he was going to come out with one. You know, you don't see someone for so many years and you still have that same mental picture of them in your head from that time.

                Now I see the pic you posted and my first reaction was.... he looks older....?, and then I say to myself wow he looks great! .... and I look very old now! HA! DUH...

                I can't wait to get my hands on one! Good Luck Ernie, I know it took a long time to finally get this out for us.


                • #9
                  Great review. I ordered one this morning and I'm really looking forward to getting it out on the track.


                  • #10
                    Thank-you for sharing such a thorough and well written review with us, Chris.


                    • #11
                      Nice to know it is finally being sold. No mention, unless I missed it, of retail price. I'd also be interested in how well the rear wing holds up to smacking the wall/guard rails a few times. Easy replacement is fine, but I'd rather not have it break in the first place. In my mind, this is the biggest defect in the version.



                      • #12
                        Thank you for the thorough review; I too wish this new venture meets with nothing but success. And the black Mazda looks great, too, kind of sinister.


                        • #13
                          It's s'posed ta be out of a high impact plastic that will take abuse....


                          • #14
                            Great review. This car is very much anticipated - it looks very good and looks like it'll be a great performer OTB!

                            Originally posted by chrisguyw
                            Both axles are hardened steel with a 53 Rockwell value.
                            I'm assuming this reading is in HRC. Just curious - what is the hardness of a drill blank?


                            • #15
                              Originally posted by Mark View Post
                              Great review. This car is very much anticipated - it looks very good and looks like it'll be a great performer OTB!

                              I'm assuming this reading is in HRC. Just curious - what is the hardness of a drill blank?
                              Hi Mark, Drill blanks are roughly 62 rockwell.