Question (by Dick Hancock #39 SM - Knoxville, TN):
Bought your adjustable FP regulator for my 1.6 Miata recently, now have it installed along with a stock AFM, Marren calibrated injectors all @ 60.6 cc/min, NGK AFX air fuel sensor, and a new Actron fuel pressure test guage with schrader valve connection on the high pressure side of the fuel rail. After installation I checked/adjusted the 5x regulator pressure at idle (950 rpm showing on OEM tach) - with the regulator vacuum hose attached I set it @ 40psi, but then noticed that if I disconnect the vacuum line it drops to around 35psi. My assumption is that I should test pressure with the vaucuum line connected - is that correct? I plan on a dyno session next week to see what pressure range gives me a 12.8 to 13.2 AFR. Also, I have a straight air filter to AFM inlet - do you recommend mounting the unmodified AFM near vertical, with the electrical connect pointing up?

5XR Answer:
Vacuum hose: disconnecting the vacuum hose is going to simulate the fuel pressure under full throttle conditions while idling, as there is no vacuum when wide open. You can tune either way, and while my father tunes his with the hose off and recommends this method because it's representing the actual "full load" pressure (he's got an engineering mind), I actually tune mine with the vacuum hose on because it is easier for my wife or mother to not have to pull off the hose when they adjust it when I pull into pit lane during a practice! (I have a "shortcut" mind). The only difference to me is in the reference numbers used for your tuning. I will say that the "hose off" method will most likely provide a more stable gauge reading, but in my opinion I want to be able to tell whoever is adjusting it for me when I pull into the pits not to have to pull off the hose before they adjust it. It's your preference really.
AFM: This is a tricky little thing. Mine AFM is tuned from the days of non-adjustable FPR's, so it is already set lean from that tuning. Here is what I know about turning the AFM on it's axis:

Plug pointing strait up is going to put your AF/R very rich, as gravity is helping the "trap door" inside the meter open up, actually keeping it open most of the time, even during off throttle coasting during the race. I've experimented with the meter like this and could not dial enough fuel out of it to reach 12.8-13.0, so I adjusted the meter back around.

Plug pointing strait down is going to lean your AF/R out as much as allowed by your AFM. Unfortunately, this setup allows gravity to work against the trap door, restricting air passage through the intake tract. This setup will be the easiest to use for tuning though, because you can turn the meter up and it will give you a leaner mix, then dial in more fuel with the regulator.

Keeping the meter flat is not recommended in my opinion, as the trap door is going to get pulled around by gravity through the g-forces experienced during turns. This will cause a fluctuating reading from the meter.

Here's what I would try on the dyno: Plan to turn the meter with the plug pointing a bit more than halfway up, maybe at 10-11 o'clock so you get the benefits of gravity helping the door, but not the full load of strait down gravity. If that makes sense!

While we haven't done any personal dyno testing for the regulators, we do all of our testing on track to both prove the reliability of the part and gauge the performance of it while in race conditions. So, we don't have any hard fact numbers on the torque curve, but we can attest to what the adjustment of the fuel pressure does to the air/fuel ratio while under full load on the track. Here is my best advice on tuning with our regulator: A couple of things need to be considered before you start tuning with our regulator. The first is having an air/fuel ratio gauge/fuel pressure gauge combo. This is a must! Otherwise, you are tuning in the dark at the track, which is what this regulator is best for. You might be able to pinpoint your best hp and torque on the dyno, but what happens when it is rainy, cold, hot, or you go to a track with hills and need more torque? It is beneficial to document what fuel pressures did what while on the dyno, a good roundabout starting point is the stock range of 35-38 psi, but I think you will ultimately end up in the low 30's or high 20's on fuel psi. 1.6 Cars: The other is whether or not your air flow meter is already tuned to try to achieve a leaner ratio. For instance, if you have an air flow meter that is already professionally tuned, most likely it is giving you an air/fuel ratio of around 13:1. Also, the trap door in the meter should be loose enough to not restrict air flow, and most likely this would be done already by the tuner of your meter. If your meter is tuned already, keep it in the car, tilt it on it's axis to allow the door to open easily ("d" portion facing down) and use our regulator to dial in your desired ratio. If your meter is stock, you can mess with the spring to loosen up the door and allow better flow, but this will richen the mixture quite a bit, so use the regulator to lean it back out. Adjusting the stock air flow meter is like a black art and I would be careful, always keep a known good one on hand if playing with this as the experimentation can throw it out of wack very easily and it might not be returned so easily. 1.8 Cars: You have it easy! Since you have no air flow meter to adjust like a 1.6, the only thing you need to concentrate on is adjusting the fuel pressure to achieve the desired air/fuel ratio. That's it! A good air/fuel ratio for the 1.8 that has worked well for us is 12.8:1. The biggest gains we have experienced have been on the tracks that require a richer mixture to yield more low end through the mid range torque. We have found that tracks that require more torque and have 2nd gear turns like an air/fuel ratio of 12.8:1 rather than the preconceived notion of 13.2:1. The extra richness in fuel gives more pull in the lower RPM range, helping you out of corners. On tracks with high speed turns and no 2nd gear digging will like a leaner ratio around 13.2:1 or maybe 13.5:1 for the extra high RPM horsepower. Before the adjustable regulators, we were pretty much stuck with the 13.2:1 ratio our professionally adjusted meter came with, and it left us lacking torque in the low and mid RPM range. I hope this info helps, it is hard to say exactly what will work for you and what works for us might not work for you, but one thing is for sure for all cars and that is air/fuel ratio's. Remember, 12.8:1 for low RPM torque and mid range, and 13.2:1 for high RPM horsepower tracks. This is where the dyno is deceiving, as you are trying to achieve the best HP, which is good for HP tracks but not torque tracks. While at the dyno, try to find what air/fuel ratio yields the best torque and you'll be ready to go when you get to the track! Thanks for reading! John Adamczyk

The flyin miata kit or similar kit is a good "all around" kit for street duty, like for a daily driver, but if you are going to prepare it for track duty you might want to go stiffer with the spring rates. The Flyin' Miata kit specs are: Front springs: 318 lb/in Rear springs: 233 lb/in Front ride height: 12.5" Rear ride height: 13" On the spec miata's we run 700 lb/in Eibach race springs in the front and 325 lb/in Eibach Race springs in the rear with bilstein shocks, which is very firm but intended for racing. We ran the same setup on a 95 Miata street car, but instead of 700 lb/in front springs I used 500 lb/in, which was still a little too firm for everyday street duty (daily driver) in our opinion. If it was an occasional weekend driver and track day/auto-x car it would be perfect though, as it handles amazing (better than the sm in balance terms). We feel that your Miata can be setup as an "all around" car, and it will handle the track duty, but for serious performance (what we do) like time trials and serious auto-x, you are better off with a more targeted setup that can at least be adjusted in terms of ride height. All in all, the flyin miata kit looks like it would fit the needs of a enthusiast street driver as it will provide a nice street ride, but you might find the limits of it for track duty. Also, it is not adjustable in terms of ride height, which means you are stuck with the predetermined balance and ride height that the kit provides. If the car pushes through turns you'll never be able to adjust it out. With an adjustable coilover kit you can set ride heights and have it corner balanced, which will allow you to get the perfect balance that you want. If you find yourself hooked on track days/autocross you might end up with something geared to accommodate that eventually. Our advice would be to attend some auto-x's and track days with the suspension you have now, then decide if you like it enough to continue, then make a decision on your suspension upgrade. Don't waste money on a kit now because you want to have a better handling car now, because once you find out that you are hooked on track days you are going to want to upgrade to a more serious suspension that allows adjustability and stiffer spring rates. Our recommendations: Ground Control Coil-Over kit with these options: Bilstein shocks or Koni yellow shocks with: 400-500 lb/in Eibach 2.5" or similar race springs in front and 300-325 in/lb Eibach 2.5" or similar race springs in the rear

While the ACT 4-puck solid hub clutch will be the ultimate track clutch for your car because of it's light weight un-sprung disc, the fact that you will occasionally drive it on the street it might not be the best overall. The best overall clutch I feel would work the best for your desired use is the ACT Modified Street Disc clutch kit: http://5xracing.com/i-1566223-1990-1993-mazda-miata-act-hd-modifed-steet-disc-clutch-kit.html This kit will have the same pressure plate as the 4-puck kit, but with a more "streetable but yet still strong enough for the track" disc. On a stock Miata, the stock clutch works fine for street driving, but when you want to start performing high RPM quick shifts, you'll benefit from an upgraded disc that won't slip as easy. The best disc for high RPM quick shifts is the 4-puck unsprung, but you will most likely experience chatter and harsh starts on the street with it, which a race car doesn't care about. The modified disc will be a lot milder as it has a sprung hub and full contact disc surface, like a stock clutch, but will be superior as it has upgraded springs and friction materials compared to the OEM disc. This disc should not chatter either, which will be more acceptable for street use and non-racing track use. All ACT "HD" kits use the "HD" pressure plate, which means "heavy duty". It has increased pedal effort due to heavier springs, but that also increases the clamping ability to over 200hp, way more than most Miata's will ever see. The kit we recommended is an "HDMM" part number, which means "Heavy Duty" pressure plate and "Modified Street Disc".

Question:
I have a 97 Miata which I will be installing Mazdaspeed Miata brakes on (calipers, carriers, etc). Which kit should I buy, the one for the MSM or the 90-2001 Miata?

Answer:
The Mazdaspeed brakes (which uses sport rotors that are bigger than the standard) will need the Sport brake lines as they need the extra inch of line to supply the now higher caliper level. So, the Sport Lines are needed for your swap. You can find these lines here: http://5xracing.com/i-6764565-techna-fit-stainless-steel-brake-line-kit-for-2001-2005-mazda-miata-mx-5.html

The bushings are actually made to be just a hair bigger to avoid being tight on the shifter, it's a really fine line from being too loose, which would cause a sloppy shifter and too tight, which would cause difficulty shifting as you are experiencing. We aim to have the bushing "snap" into place on the ball, and when on the ball, it must be able to rotate around on the ball end. If the bushing is a tight fit on the ball end and will not rotate, then it is too tight and will cause difficulties in shifting. We test fit every bushing onto a Miata shifter that we have here before we ship it, so I know that the bushing we sent you passed our inspection, however, I know there are slight variances in different shifters, so it is possible that the ball on the bottom of your shifter is just a bit larger from manufacturing variances. The bushings will eventually "break in" with use, but in the meantime what we would recommend is removing the shifter and remove the bushing, then take the ball end of the shifter to a wire wheel for a bit to clean it up, or at the very least an abrasive pad, such as a red scotch-brite pad, and essentially "break in" the ball end of the shifter by cleaning up the surfaces. If you have a way to break in the inside of the bushing that would work just the same. A dremel tool with a very small sanding attachment might work for this. The point is to create just a little more tolerance for your specific application, as all shifter ball ends might be just a little different. After cleaning up the ball end of the shifter, use a little bit of oil from the transmission turret and lube the inside of the bushing and outside of the ball end and see if the bushing fits any looser. If all else fails, we will always take back a bushing that is too tight and replace it with another one.

Question:
Am driving a Volvo XC60 (2010) T6 AWD.......any carbotech brake pads to recommend? I read only the 1521 is suitable for street driving.....I don't track but is it still suitable for occasional 'track style' street driving? My SUV's kerb weight is about 1900KG......1521 suitable?

Answer:
All Carbotech brake pads are great for just about anything, whether it's street or track based driving. The 1521 pads are great for street driving, and even autocross, but are not recommended for track driving because they're not built to handle the additional heat generated from track driving, they are designed to be a pad that will provide superior braking capabilities over your OEM pads, produce very low dust levels, and last several times the life of your OEM pads. For an SUV such as the XC60, I really think the 1521 will be great, BUT, if you really want to step up your braking, you can go with the AX6 compound, which is built to be an autocross/light track use type pad. The AX6 will produce more dust and might squeal a little bit at low speeds, so there is a compromise going with the more aggressive pads. Our suggestion would be the AX6's. European cars tend to have great brake pads already, but produce more dust because, which is similar to the AX6. It also sounds like you enjoy some spirited driving, so you'd appreciate the stronger braking that the AX6 will provide.

Question:
Hi, I have a few questions about the hub service that you guys offer for the miata. What is the turn around time for the hubs? I can take them off my running car and send them over. Also my Miata will be seeing the track about once a month consistently, but its not a race car. So what kind life expectancy can I get from the hubs from your service? I was going to buy brand new oem hubs, but this seems to be a better option and much cheaper. Finally, would you also be able to redo the rear hubs?

Answer:
The turn around times can be long depending on how busy we are with current projects and work in our shop at the moment. If we are in the middle of race season and are busy rebuilding our cars, or have a lot of service work lined up before your order, it could take anywhere from two weeks to a month in some cases. Patience must be taken when sending us hubs or brakes to service.
We offer a more street/track day friendly hub service using the Red Line bearing grease, which is a heavier all-around grease than what we normally use for our race service, which is a very lightweight race grease for ultra low rolling resistance. We recommend that our race greased hubs be monitored every couple of races (shake the tire back and forth to make sure there is no slop or play in the hub) and repacked after about a seasons worth of racing, which is pretty standard for the typical racer anyways. With the Red Line grease though, I would feel that it is safe to say after our service, the hubs will be good indefinitely. If it's only track days you're participating in, the only thing that will determine how often the hubs need to be re-greased is how much you run in the rain, as water can eventually thin and wash out some grease within the hubs. We have a lot of our hubs out there on customer cars, and even had a set on a chump car miata that ran in a 24 hour race using our race grease without any problems, so I know our service holds up if it made it through that type of competition!
We have done rear hubs before, but I must warn they are hard to remove from the car without the proper tools and will be heavy to ship. We do have the ability to service them though.
I do feel that our service on an older set of hubs is much better than a new set of hubs. They will roll much more freely as the grease we use is a lot less restrictive (oem grease is like wax for water concerns).