Changing tires and new partners

An ongoing challenge that we've had with our car is a lack of grip with cold tires.

While we've loved our Hoosier R75 radials when they got hot, it took a bit of work to get them to the right temperature.  Not only did we have to fight the lack of grip when outside temperatures were 80+ degrees, but if the outside temperature was cooler, it was even tougher.

As the first driver in the car, Karl Coleman usually spent most of his first run getting heat in the tires.  Ron's first runs were then better, but it usually took at least a run from each driver to get the tires working well.  The same went for Alyson and Amy on the Ladies side.

Hoosier slicks have a few different compounds, with A25 being the softest, R35 being in the middle, and R45 being the hardest.  For autocross purposes, softer is usually better because they work better right out of the box.  The potential danger is that they can overheat quickly.  Unfortunately for us, there is only one compound available in the size that we ran.  The R75 compound is in between the R35 and R45.  Although we never had to worry about them overheating, we did have to worry about getting and keeping heat.

The earlier Miatas were starting to switch over to softer compound tires, making them even faster.  Jim Daniels in his '94 Miata started running Avons, while Drew Vanderploeg and Steve Hudson made the switch to 110 compound Goodyears.

Our team had been looking in to trying out Goodyears based on the very impressive results of EM driver, Jeff Keisel.  However, the cost of their Radial Slicks were extremely high, even when compared to the Hoosiers we were already running.  It's hard to spring for a $2000 set of tires not knowing if they'd be faster than what we were already running.

Jeff made the trek up for our National Tour in July, so I took them time to talk to him about the Goodyears.  He said that the compound on the radials was way too hard for our autocross purposes and that I should give the bias plies a try. 

When building the car, I wanted to keep with newer technology, starting with the car, and following through to the tires.  It seemed like a big step backwards to run old technology bias plies when radials were available.

The bottom line, however, was that we needed a softer compound, and the Goodyear 250 compound was softer than our Hoosiers.

Fortunately for us, our friend and multi-time National Champion, Andy McKee had started running these tires on his XP RX-7.  He only ran the 23.5x11.5x16 tires on the front of his car, but was willing to part with a used pair for us to test with.

After receiving them, we mounted them up and put them on the front of the car.  We didn't make any changes to the car, figuring that we needed to see first if they were at least comparable.  The intent initially was to run them in the morning at the first event on the front of the car and then switch them to the back for the afternoon.  To our joy, the first run out showed them to be better than the Hoosiers on initial turn in.  The car also rotated better overall throughout all of the runs.

Needless to say, we didn't switch them to the back of the car, as that would have been an excercise in futility with the front washing out everywhere.

We were able to continue running the tires with quick turnover allowing us to test with lots of heat in the tires, and they didn't seem to lose grip due to overheating when compared to the harder compound Hoosiers.

This made the decision easy to switch from the Hoosiers to the Goodyears.

What needed to happen next though, is that we had to change the setup of the car to match what bias plies like.  While we were able to use as much camber as we could for the Hoosier Radial Slicks, bias plies like very little camber. 

This left us with a little worry, as the rear suspension gains camber as the car is lowered.  We obviously didn't want to add ride height.  We took the car to our partners at Clarks Wheel Alignment and they aligned the car for us.  As expected, they were able to get the front to the numbers we were looking for, but the minimum amount of camber they could get out of the rear was over 2.5 degress of negative.  We were looking for 1 to 1.5 degress, so that left us in a pickle.  To add to the problem, even if we could get less camber, we would end up with the toe way outside of the specs we wanted.

The rear of the MX-5 has a multi-link set up, with five different links comprising the suspension. One link is specifically for camber, while another is for toe.  These links are non-adjustable, using cams to to change the effective lengths.

So, the obvious choice was to get different length links for the toe and camber.  Unfortunately, no one was offering different links for the MX-5.  We did find a couple of companies that offered adjustable links for the RX-8, which is very similar to the MX-5.

One of those companies was Megan Racing.  Megan Racing specializes in suspension, exhaust, and brake components for a number of performance cars.

They offer all five links with adjustable ends and spherical bearings for the RX-8.  We contacted them to see if they had tested these on the MX-5 and were told that they hadn't.  We offered to test the toe and camber links on our car, so they sent them off to us. 

Upon opening the boxes, our first reaction was that they were very high quality, with a beautiful blue powder coating.  They looked plenty strong, being more robust than the stock links.  The arms are also adjustable on the car, without disconnecting anything.  These guys at Megan Racing were great to deal with and have great products.

 Comparison of stock toe link to the Megan Racing link, part number MZ-1470

Comparison of stock rear link to the Megan Racing link, part number MZ-1410 

 

Upon Comparison to the stock arms, it appeared that both would work, although the camber link had a shorter stud on the heim joint that goes into the rear hub.  We mounted them up, and while we would prefer a longer stud, everything fit well.  Installation was simple, as it was a simple unbolting of the stock links and bolting the new links back in after adjusting the lengths to be close to the stock arm length.  Megan Racing is working on a camber link specifically for the MX-5 with a longer stud.

 

 Rear camber link

Rear toe link

 



The adjustments on these links allowed us to set them close and then fine tune with the stock cams used on the stock links.  Upon taking the car back to our friends at Omni, we were happy to see that these new links allowed us plenty of room to get our alignment specs where we wanted.

Our starting point on alignment is -2.2 degrees of camber with 0.06 degrees of toe-out in the front, and -1.5 degrees of camber with 0.06 degrees of toe-in in the rear.  We will probably look at going even less on the camber based on the current wear.

New exhaust and rear swaybar

We built our car using a Goodwin Racing exhaust consisting of a short tube header, midpipe (including a small, high-flow cat, and a reasonator,) and muffler.

Always looking for more power to try to even out our power to weight ratio with the earlier cars in the class (remember, we're still running our stock 98,000+ mile motor,) we were excited to hear that PPE Engineering was coming out with a new long tube header setup.

The advantage to the Goodwin header is that it is the same length as the stock header and therefore allows any part of the stock exhaust to be replaced with their higher flow pieces.  The downside of course, is that a short tube header is never going to put out as much power as a long tube header.

Since the team had purchased another 2006 MX-5 for a daily driver, it was an easy decision to put this new PPE exhaust on the DP car, as we could move the Goodwin stuff over to the daily driver.

The PPE exhaust came with the new long tube header and a shorter midpipe, which then connected to the Goodwin muffler.

A comparison between the Goodwin Racing short tube header (top) and new PPE Long Tube header

 

 

 

While we didn't do any dyno testing between the two units, there were a few independent people that did, and the PPE combo showed an increase across the board.

 

Secondly, we'd been running the stock rear swaybar since very early on in the development of the car.

 

Although the car has been working quite well, especially locally, we were looking for more rotation when running on concrete.  We don't have any sites locally that run on concrete, but the National Championships in Lincoln, NE are.

 

So, we ordered up a Racing Beat rear swaybar.  It is a 19mm bar vs. the stock 12mm and comes with urethane bushings and two holes for the endlinks to allow for adjustability.

 

 

 

The Sand and Sage club in eastern Washington was holding what will hopefully be an inaugural event in Ellensburg on a concrete pad at Bowers Field at the beginning of May.  So, we put the new bar on for a local event at Bremerton Raceway the weekend leading up to the Ellensburg event. 

 

We placed the bar on the softer of the two settings expecting the car to oversteer since we were on asphalt, but to our surprise, the car rotated better than it previously had, but was still very controllable.

 

When we made the trek to Ellensburg, we placed the bar on the stiffer setting.  It worked very well, with us taking the top Pax for the weekend.

 

Later in the season after running the Nationals Championships on the stiffer setting, we ran a local even on the stiffer setting, and the car still worked better on asphalt.....  While the car rotated better at Nationals than the 2011 event, we would still like to have even more stiffness in the rear.

 

So, we will very likely be looking at an even stiffer rear bar in the future!

 



New minimum weight for 2012

In the Prepared classes, each car and class have mimimum weight requirements.  Most of the classes use similar formulas, but they can vary.  In DP, the minimum wieghts are based primarily on displacement.  The purpose behind the minimum weights is to try to create parity amongst the different cars in the class.

When we built our car, the formula was as follows:

Engines with displacement less than or equal to 1667cc:

1.10 x displacement (cc)

Engines with displacement greater than 1667cc:

0.95 x displacement (cc) plus 250 lbs
In addition, due to the age of the rules, there was also a weight penalty for cars running wheels wider than 7".  In general, many of the cars running in Prepared have been older cars, and thus 7" wheels used to be considered wide.  That weight penalty was 75 pounds for wheels up to 10" and 150 pounds for wheels over 10".

Therefore, the formula for our car was:

0.95 x 1999 (displacement) plus 250 lbs, plus an additional 75 lbs for our 10" wide wheels.

Total minimum - 2,225 lbs

As a comparison, our primary competitors in DP are 1.6 L Miatas and 1.8 L Miatas.  Their minimum weights were 1,758 lbs and 1998 lbs, respectively.  So, there was a 240 pound difference between the two earlier Miatas, and then another jump of 227 pounds to us.

Prepared rules allow for pulling a lot of weight out of the car since these are effectively full on race cars.  Unfortunately, a bone stock MX-5 comes from the factory weighing a published 2,441 pounds.  And, in fact, our previous CSP MX-5 weighed only about 2,320 pounds. 

We obviously took advantage of the weight reduction rules when building the car, and ultimately had to add back about 225 pounds to the car to reach the minimum weight requirement.  The nice thing was that for local events, we were able to run with a passenger in the car and be at our minimum.  For big events, we had plates of steel that we put in place of the passenger seat.  We got these steel plates from our sponsor, Where2Race.  They were coated in rubber for moisture protection/rust prevention.  Due to their size, we were able to place the front of them on the support rail that the front of the seat bolts go into, and then drill holes through the plates to use the factory rear seat mounts.  We then used some 1 1/2" steel strapping between the front and rear seat mounting points to hold the weight securely in place. 

By using the factory mounting holes for the seat, we were able to make it a fairly easy change between local events and big events.

Fast forward to the winter of 2011/2012, and a change in the minimum weight calculations.  Since pretty much everyone in the class had to add weight to the car to reach the minimums, the SEB (Solo Events Board) made a change to the minimum weight calculations for DP.

The new formula is as follows:

Engines with displacement less than or equal to 1667cc:

1.06 x displacement (cc)

Engines with displacement greater than 1667cc:0.91 x displacement (cc) plus 250 lbs

 

Of additional importance, is that the 75 weight penalty for up to 10" wide wheels went away.  For us, that changed our minimum weight to the following:

 

0.91 x 1999 (displacement) + 250 lbs, for a total of 2,070 lbs. 

 

This change allowed us to shed 155 lbs for the 2012 season.  Since we were using either steel plates or a passenger for approximately 225 pounds of add-on weight already, this was an easy change to make, as we only needed to reduce how many steel plates we had in the car for National level events.

 

The finished product with the steel plates firmly in place for the 2012 season.

 

 

Adding flares

Sometimes when building a car, things get done slightly out of the order of what would otherwise be preferred.

In the case of the Bauerspeed Racing MX-5, one of those items was the cutting of the fenders and addition of flares.  Preferably, this would have been done prior to getting the car painted.

To be fair, the flares that we ended up putting on the car weren't available at the time that the initial work was being done, but we did end up getting lucky with the tires not having extreme rubbing issues with the otherwise stock bodywork.  Of course, part of the reason for this was the ride height that we were at.

While we had experience previously with running wide 285/30/18 tires on 18x9.5" wheels on our CSP MX-5 without cutting the fenders/quarter panels, the shorter, wider 23.5x11x16 tires on 16x10" wheels that we run on the DP car were going to be different.  Since the tires are an inch smaller in overall diameter, that meant that the DP car would be lower, which would affect offsets, etc.

So, as it turned out, we were able to run the car with just an extreme rolling of the fenders and quarter panels.  However, the car was not nearly as low as we would like it.  To get it to the height that we wanted, it would require cutting the fenders to allow the needed wheel/tire clearance.

As you know if you've been following the build, we are VERY proud of our body and paint work on the car, so cutting the fenders would detract from the beauty of the car, as it would be very difficult to make the lines look right.  In addition to that, there is always the danger of messing up the paint with the actual cutting.

Enter the SEMA show and a one off, special edition MX-5 that Mazda brought.  The "Super 20" had flares that not only looked like they would allow the extra clearance needed to cover our big tires, but would hide whatever cutting of the stock fenders would be needed.

Sounds great, but the problem was that these flares were also one-offs.  Fortunately there was a great enough clamoring amongst MX-5 owners, that Goodwin Racing was able to get the okay to have these flares built for sale.

The flares were built from fiberglass at the time that we bought them, although they are now available in urethane.  Timing of course is everything, and were we to do it again, we'd definitely order them in urethane for a couple of reasons.  First of all, they are more flexible (below you will see why this is important,) and secondly they would be more sturdy/less breakable.

We were able to see pictures from another owner that bought these for his daily driver and noted that there were a couple of negatives to the flares.  It turns out that the flares were really more of a cosmetic item as built.  The attachment to the car was by double stick tape both on the body of the car, and on the inside of the stock fender lip. We had already rolled the stock fenders, so there would be nothing to attach the flares to inside.  Also, this area is where we were looking to gain additional clearance.  Secondly, the flares were one piece items.  Seems okay, but as the flares are being held to the car with double stick tape, this would make removing the bumpers and side skirts very difficult.

These same pictures did however show us that the flares looked to bring the body lines out far enough to cover our tires if we did some extra work.

So we ordered up a set and mocked them up on the car.  As we expected, they did increase the overall width of the body work.  Next up would be taking advantage of this extra width.

Okay, enough talking, here are some pics.....

This picture shows why we needed to cut the fenders in order to allow proper tire clearance.  Obviously, we couldn't lower the car too much or the tires would start hitting the fenders.  This picture is of the rear, but the front was very similar.

 

 

Here is what the flare looked like from the inside prior to cutting along with the intial piece cut off where the fender lip was.  Futher trimming would be done later to fine tune the whole thing.

The first picture is of a rear flare and uncut fender, while the second is of a front.  As you can see, there was probably a little over an inch at both ends of the car.  While it wasn't extreme, keep in mind that this was with the fenders already sporting a very heavy roll/flare with my fender roller.

I used painters tape to allow me a clean cutting area.  The second picture shows the actual line being cut on the rear.  The tape allowed me to see where I was cutting and also allowed a little extra protection to the paint.  I used my Dremel tool with 1 1/2" thin cut discs for the cutting of both the fenders and the flares.  They are reinforced discs that allow for fairly precise cutting, and don't wear out excessively fast.

The first picture shows the rear after being cut.  As you can see, there are two parts to fender back here.  The quarter panel attaches to the inner fender normally at the fender lip.  So this required cutting both the outer and inner fenders.  I then took my fender roller to the inner fender to help push it up a little more.  Fortunately it is fairly flat, so even if the tire hits it, there isn't any damage to the tire.  The second picture shows the tire now tucking in under the flare.  Both of these pictures are with the shock out to show what would happen under compression.  The front fenders were much easier to cut as it is just the one piece fender.

Here you can see the car after the cutting of the fenders, without flares.  This gives a good idea of what the clearances are at static ride height.  Obviously the car is nowhere near as pretty.  The cuts could have been done much better if the flares weren't being put on, but all I needed was clearance, not beauty.

I can't seem to find pictures of the additional work I did to the flares, so I will describe it as best I can.

First of all, I wanted to make sure they were strongly attached to the car.  As previously noted, the provided attachment was double stick tape along the tops to the body work, and then inside the fender lip.  Since the cutting that was done took away some of the attachment points, I decided to screw the inner portion to the lips down towards the bottom of the car.  This required drilling holes in the flares and the lips.  I then used rivnuts in the lips so I could screw them in.  This was subsequently strengthened with more double stick tape.  I used 3M "Super Strength Molding Tape."

Secondly, I decided to cut the flares along the stock mounting points between the bumpers, sideskirts, and body/fenders.  This was challenging to match the stock lines due to the curvatures involved.  In the end, I used a laser level to line up the stock cuts and then drew lines on the flares which I then cut to match.  While the match didn't end up 100% perfect, it is very close.

An unfortunate byproduct of this cutting was that the flares no longer matched up at the cut lines.  The reason for this is that the flares needed to be twisted a little to fit tightly against the body work.  I could twist them to match up by hand, but it would require some way to hold them together other than my hands....  ;-)

My first attempt used double stick tape attached to 2" by 3/4" metal pieces.  I then put these at the seams to hold it all together.  This took a couple of tries as the tape didn't stick very well to the flares due to the fibers in the fiberglass.  The other downside to this solution was that it didn't help with the reason that the cuts were made in the first place, namely the ability to remove the bumpers. 

In the meantime, we took the flares to our friends at Pacific Auto Body.  They did an outstanding job painting the flares to match their previous work to the car.  The finished product was incredible.  However, we still had problems with the double stick tape coming off at our mating points.

In my mind, velcro seemed like an obvious solution, but the problem was that there was a bit of a force needed to get the two sides to match up.  Typical velcro wouldn't be strong enough to hold.  After looking around and doing some research, I came across something similar to velcro, but much stronger.  I purchased it at Radio Shack, and it is called "Superlock Fasteners."  It has high strength tape on one side and the other side is bascially a bunch of small plastic mushrooms.  When two pieces are mated, they create a very strong connection which is similar to velcro, but much, much stronger.  This allowed me to use the same metal pieces from before with one side attached to that.  I then attached one piece to each side of the flare.  When mated together, the small metal plate, holds the flares together! This solution was used for the front, as I was able to use some additional double stick tape in the rear on the bumper portion of the flare to put it where I wanted.  The added benefit to this velcro-like solution is that if the flare gets hit hard enough by a cone, it will just pull the "velcro" apart rather than pulling the tape off of the flare.

And here is the car after the flares are attached and painted. Beautiful and very functional. 

Way past due....

As if my last post was a long time in coming, I've now realized that I missed this whole season.

So, now that it's Thanksgiving already (WOW,) and we're in the offseason, it is time to catch up on what's happened both to the car over this past year, as well as Bauerspeed Racing's success over the season. 

The team is off to spend the day with the family today, but be looking for new updates very soon.

Here's a small glimpse of what we'll be posting about:

From this past season:
- Adding of flares
- Lowering the car further
- Switching tires
- New partners! - Megan Racing and Clarks Wheel Alignment
- Changing minimum weights
- Corner balancing
- Addition of a second car to the team (really a daily driver, but a good backup)
- Team results - Local events, National Tours/Pro Solos, and National Championship

Things to be done over the off season:
- Further moving around of weight - relocation of fuse box, ECU, and battery - modification to the front bumper support
- Addressing the lack of power(!)
- Adding a front splitter

So, obviously a lot that we need to catch up on.  See you soon.