Tuning a Mazda 2

[walterclark]

I doubt the tuner is suggesting running around at 7300 a lot. What is sounds like is a racer needs to keep it above 4000 to stay in the power band. From what I can see only in first does the RPM need to exceed 6300 to hit 4000 in the next gear. Based on the math it needs to hit 7200 in first to get 4000 in second. After that it can be shifted around 6000 and hit 4000 or above. Given how short a time the engine would be in first and need to be above 6000 in a hillclimb (maybe 1 time for 2 seconds per run?) or any other race for that matter I doubt the added stress would be easily measured. Now, if that 6300-7300 became addictive and the driver started doing it in every gear, that might start stressing things which like to turn slower, such as Paul mentioned - alternators, water pumps, A/C, P/S, etc.

BTW. The math is extremely simple for the RPM versus gear if one just wants to use a pocket calculator. Divide the lower ratio number (second gear in this case) by the higher one (first gear) then multiply that times the RPM reached in the higher ratio gear (first) and you have what the matching RPM would be in the lower ratio. Of course one could expand this in a spreadsheet to include all the gears, and even the final drive, tire diameter and speed.

I came up with what could explain the higher second gear RPM that was reported...slipping of the clutch. Not that is slips all the time but even if you just dumped it there will be some slippage for a moment unless the car has a pressure plate well beyond what the manufacturers put in production cars. Those kind of cars tend to be miserable to drive in traffic. Generally slipping the clutch is not something you want to do in racing unless the only other choice is bogging the engine, because you are not putting all the power to the road - some of it is heating up the clutch, pressure plate and flywheel.

[sdwarf36]

What I would suggest-find somewhere thats having a "dyno day". You might get a couple of runs for $50 or so. Dont worry about any tuning-just get the graph. For one, you'll see if your tach is accurate. And for another you will see where your peak hp is. If you peak power is at 6000rpm, there is no sense worrying about raising your rev limiter from 7200. Even if you do a few bolt ons, the general shape of your dyno graph will stay the same. You may pick up in some areas-but without drastic changes, where it falls off is pretty much gonna be the same. Yes the internals on the engine will stay alive turning-say-8000, but how the port flows-how the cams are set-how its fueled + timed etc. have gone way past whats efficent long before.

[hammer]

You're probably right. It very well could be a combination of clutch slippage and my tach not being 100% accurate that's why I'm getting the results I am.

[Chief Geek]

Hammer

I noticed the Moultroup bit in your post signatures. Did you and Challenger intend to come up with opposite solutions (cars) to the same problem (hillclimb vehicles)?

It will be very interesting for me to see how your times look compared to mine. Of all cars in the world, I know Miata's and 2's best and you and I will each be running one. Should be interesting. No, I'm not trying to create a grudge match between a pair of 100 hp Mazda's. That would make the hill rumble. ;) For a while, the only times I'm going to be interested in are from my last run and the one before.

Paul

[hammer]

Paul,
Haha. As much as we both share our love of cars (we are brothers after all), he goes for power and large displacement whereas I prefer lightweight over all else. Hence the reason I got a Mazda 2 over say a Fiesta. Can't beat 2300 lbs!!

I will definitely be starting off nice and easy. This is my daily driver as well, so I don't want to go crazy! But it will be very interesting to see how our two cars compare as well! I'm not totally against a little competition I like to remember what Autoblog said a couple years ago in their review of the 2:

The concept of driving slow cars fast is one of which we're quite fond. Anyone can hop in a 1,000-horsepower supercar and leave in a cloud of smoke and testosterone. The real entertainment is found in working hard for every hash mark on the speedometer. Fortunately, the 2011 Mazda2 is nearly sadistic in how much it enjoys being pushed hard.

[Mopar 151w2]

Wellll.... Sam may to be chagrined to find that the Howe Mod and his Mazda 2 weigh within 100# of each other. Further, among the arsenal of wheels that Luke got from Smokey are some R&R ultralites that are about the same weight as Sam's stock Mazda wheels - especially when weighed with tires. (I know, I used to own 'em.)
And the driving techniques are less different than you might think - my best finishes as a driver were when I had bog-slow street cars, and several of our best "big power" shoes (including Smokey) have a background in trucking or heavy equipment.
Thanks to Cheif Geek, we can now compare (and bet beer on!) split times in individual corners - this should be an interesting year in the Moultroup pit.

Fianlly, my last win in this series was against Maros Zelina - and I beat him in the twisties, not on the straightaways.

[KevinGale]

The concept of driving slow cars fast is one of which we're quite fond. Anyone can hop in a 1,000-horsepower supercar and leave in a cloud of smoke and testosterone. The real entertainment is found in working hard for every hash mark on the speedometer. Fortunately, the 2011 Mazda2 is nearly sadistic in how much it enjoys being pushed hard.

Entertainment is a good way to put it. It's fun and challenging without being so unforgiving of mistakes. More than once I've described driving my car to riding a bull. It's intense and I love it but the fact that I'm always worried it is going to throw me off and stomp me to death does take away some of the fun factor.

[DaveEstey]

If you're looking for a bit more pep, get smaller diameter tires.

[hammer]

I hadn't thought of smaller diameter wheels. Though there are some 15x7.5 rims I'm looking at that only weigh 11.5 lbs! And I can fit wider rubber on them too.

http://www.good-win-racing.com/Mazda-Pe ... 785M2.html

[Mopar 151w2]

Rubber gears ! Works a treat, lowers the car, too.

And an old racer's adage applies : A pound off the wheel (or tire) = 10 pounds off the car I'm sure someone can be even more specific, and the diameter change gets involved, too.