How to ruin the handling of an MX5.by Norman H Gar

[Hjt]

Also a question for Guran, your best with the r888 so far is a quoted 1.16:22, I know they will improve etc and they are fairly new. Do you see yourself getting a new pb on them?

Mitch runs a stock motor with suspension modifications, his best on the r888 is a mid 1.13, he does have a torsen diff, but that wouldn't be 3 seconds alone would it?

[Patrick Bramston]

So it seems that Mark Hellmun can do 70 kph through the fishhook with all the RIGHT modifications compared to guran doing 67 kph with none, both on semi slicks.Turn 10 is 62 verses 66.Plus Mark has done a million kilometers around Wakefield fine tuning that car..Norman is not far off the mark, Mazda got the handling pretty right in the first place...

[Guran]

Also a question for Guran, your best with the r888 so far is a quoted 1.16:22, I know they will improve etc and they are fairly new. Do you see yourself getting a new pb on them?

They're definitely not new now! I'm down to the treadwear indicators already and they're still crap. I managed a 1:16.20 on the last lap of the day - very quick conditions too. Struggled to get even heat into them and they were only good for one hot lap before I had to back off and then have another go. The left side was reasonably even but was overheating the outside shoulder at 27psi. The right side was hottest on the inside shoulder and the middle was about 30C at 25psi! I've tried higher pressures too, which was worse from the first lap. R888s simply do not work properly on a stock car. They were slower than Star Specs and much more difficult to use too. I hate the bloody things.

[Guran]

So it seems that Mark Hellmun can do 70 kph through the fishhook with all the RIGHT modifications compared to guran doing 67 kph with none, both on semi slicks.Turn 10 is 62 verses 66.Plus Mark has done a million kilometers around Wakefield fine tuning that car..Norman is not far off the mark, Mazda got the handling pretty right in the first place...

Oh there's no doubt about it - Mazda did a superb job from word go. My Vmins are always near the top of the list compared to other road cars tested by Motor magazine. But T8 and T10 are the slowest corners which are the hardest to "get right" and a 5% higher Vmin is massive. Especially because both are followed by long straights, so exit speed is critical.

Oh and that 67km/hr in the fishhook was yesterday on R888s - I overcooked the braking and was in a wild slide to make the corner. Maybe I ought to do that more often?

[Hjt]

Thanks for the info, back to Bridgestones I guess?

[hks_kansei]

I would love to see a comparison of all models in the stock form, similar driving conditions, tyres and driver.

I know the later models would be faster p 2 p, but the corner speeds would be interesting.

I seem to recall an old issue of Motor MAgazine did that, they had NA, NB8A, and an NC (first version, since when the mag came out the NC had not long been released)


I think the NB8A was the fastest (not by a great margin though)
I think the NB8A also held higher corner speed than the other's as well? (can't remember, it was ages ago)

[manga_blue]

Don't just look at the slow corners. Hellmun is seriously faster through that technical T3/4/5 medium speed set at the top of the hill.
Hellmun/Guran
T3 127/115
T4 99/94
T5 100/86

That little section is probably the best quick test of track driving and handling in the country. I was pretty shocked when I saw those speeds. It follows then that mods done well, backed by the skill to use them, can make a huge difference.

[bensale]

Ref MX-5 generations track comparison... Same track, driver etc.. Watch this space...

[Basho]

For my car, with the tyres I've tried in 185/60R14 ... RE001 are my ideal choice for street use. Star Specs are a better tyre in the dry and especially in the wet, but I don't think it's worth paying nearly double for them as an everyday street tyre. Track is a different story.

Thanks for that

[Hellmun]

Vmin only matters if the lines dríven through the corner are exactly the same, I can drive a corner slow in/fast out, transient (e.g brake minimally and coast keeping the load on both outside corners but delaying acceleration) and lastly fast-in/slow out by braking late, trail-braking through the turn and getting on the gas very late. So yes Vmin contributes to analysis but it's relatively worthless on it's own. Best comparison is 1 driver, 2 cars and only one of those cars is modified with superior suspension/tyres. If the modified car is setup right it'll be faster, no ifs or buts there. That said shocks/swaybars etc are not grip givers, they're about directing the grip where it's needed most so it is essential they're bench-marked and setup correctly. I bet Bryan can get my car around Wakefield faster than 1:15 for instance, even if I detuned the motor to have the same power at the wheels.

I'm sure the author was only intending to dissuade street car drivers from modifying their cars. Without experience, a safe place to benchmark and lots of knowledge modifications will often be detrimental, especially on the street. How the handling is ruined is subjective though. I personally love the way my car handles and no-one has dríven it and said a bad word yet...well not about the suspension anyway.


Just to touch on a couple points made.

Wider/bigger wheels...agree, increases unsprung mass, buggers grip
Lowering...agree, buggers camber geometry
Sway bars...huge agree, reduces grip and advantages of independent suspension
bigger brakes..agree, increases unsprung mass
big camber..agree, reducers grip, increases braking distances
almost anything you can think of...except springs

Wider/bigger wheels only net improvement if the rest of the system is modified to support it. Tall wheels allow big brakes and wide wheels allow wide tyres which have many advantages on the track. Downforce scales much better when it's in combination with wide tyres (tyres have deformation limits so there are actually negative returns that get steeper as the rubber gets thinner and has to deform more in the longitudinal axis). Heavy cars show you this, they actually get more total grip (grip = coefficient friction * weight) than a light car which is why they wear out tyres faster . Problem being that they then need more grip to change the direction of the proportionally higher weight. Notice the WTAC cars run as wide rubber as possible?

Sway bars transfer grip , they only reduce grip if setup incorrectly. My tyres would wear horribly without my aftermarket sway bars and seeing as I don't lift any wheels off the ground or run out of suspension travel I'm not losing any independance on track surfaces. I even buck the well regarded trend and run a 16mm rear bar happily let-alone no swaybar at all.

Big Brakes don't overheat as easily, can give you higher clamp force and in a high powered car especially are more economical as pad life is better with larger pads living at lower temperatures. Again only relevant if the rest of the car is appropriately modified else it would be incredibly difficult to exploit big brakes on a slow lightweight car (you'd be able to brake a little later but it'd be proportionally small and like on TG will probably make you slower even with a professional driver). Also lots of upgrade brakes are lighter than standard anyway due to materials changing.

One other quick bit, he said body roll doesn't affect grip which is correct but only paints a very small picture of a big system. First the car will always take longer to transfer it's weight around, second is you'll ruin tyres quicker by overloading the outside shoulder. In a single sprint lap it's less of an issue, in a 8 lap race your going to get creamed by someone with a proper alignment because they'd use their tyres so much better. Simple example using Bryan, does he run a standard mazda alignment or track alignment maxxing out camber and castor? I'm pretty confident it's the latter. That TG episode should be disregarded too, there are heaps of variables left out (track temp? Warm-up laps on the semi's? wind direction and speed?) not to mention it's just meant to be entertaining.

Cars are complicated... and nothing is net pure positive (even those grippier tyres cause more friction when accelerating on straights). I've actually had more fun doing fine tuning and just driving my car the last 2 years... than I did trying to get it to work the previous couple without constant changes being made. Enjoy it and above all else modify the car in the way you enjoy, be it track times or aesthetics you determine whether it's a good or bad modification.

[vrmmmpshhh]

awesome awesome post

Vmin only matters if the lines dríven through the corner are exactly the same, I can drive a corner slow in/fast out, transient (e.g brake minimally and coast keeping the load on both outside corners but delaying acceleration) and lastly fast-in/slow out by braking late, trail-braking through the turn and getting on the gas very late. So yes Vmin contributes to analysis but it's relatively worthless on it's own. Best comparison is 1 driver, 2 cars and only one of those cars is modified with superior suspension/tyres. If the modified car is setup right it'll be faster, no ifs or buts there. That said shocks/swaybars etc are not grip givers, they're about directing the grip where it's needed most so it is essential they're bench-marked and setup correctly. I bet Bryan can get my car around Wakefield faster than 1:15 for instance, even if I detuned the motor to have the same power at the wheels.

I'm sure the author was only intending to dissuade street car drivers from modifying their cars. Without experience, a safe place to benchmark and lots of knowledge modifications will often be detrimental, especially on the street. How the handling is ruined is subjective though. I personally love the way my car handles and no-one has dríven it and said a bad word yet...well not about the suspension anyway.


Just to touch on a couple points made.

Wider/bigger wheels...agree, increases unsprung mass, buggers grip
Lowering...agree, buggers camber geometry
Sway bars...huge agree, reduces grip and advantages of independent suspension
bigger brakes..agree, increases unsprung mass
big camber..agree, reducers grip, increases braking distances
almost anything you can think of...except springs

Wider/bigger wheels only net improvement if the rest of the system is modified to support it. Tall wheels allow big brakes and wide wheels allow wide tyres which have many advantages on the track. Downforce scales much better when it's in combination with wide tyres (tyres have deformation limits so there are actually negative returns that get steeper as the rubber gets thinner and has to deform more in the longitudinal axis). Heavy cars show you this, they actually get more total grip (grip = coefficient friction * weight) than a light car which is why they wear out tyres faster . Problem being that they then need more grip to change the direction of the proportionally higher weight. Notice the WTAC cars run as wide rubber as possible?

Sway bars transfer grip , they only reduce grip if setup incorrectly. My tyres would wear horribly without my aftermarket sway bars and seeing as I don't lift any wheels off the ground or run out of suspension travel I'm not losing any independance on track surfaces. I even buck the well regarded trend and run a 16mm rear bar happily let-alone no swaybar at all.

Big Brakes don't overheat as easily, can give you higher clamp force and in a high powered car especially are more economical as pad life is better with larger pads living at lower temperatures. Again only relevant if the rest of the car is appropriately modified else it would be incredibly difficult to exploit big brakes on a slow lightweight car (you'd be able to brake a little later but it'd be proportionally small and like on TG will probably make you slower even with a professional driver). Also lots of upgrade brakes are lighter than standard anyway due to materials changing.

One other quick bit, he said body roll doesn't affect grip which is correct but only paints a very small picture of a big system. First the car will always take longer to transfer it's weight around, second is you'll ruin tyres quicker by overloading the outside shoulder. In a single sprint lap it's less of an issue, in a 8 lap race your going to get creamed by someone with a proper alignment because they'd use their tyres so much better. Simple example using Bryan, does he run a standard mazda alignment or track alignment maxxing out camber and castor? I'm pretty confident it's the latter. That TG episode should be disregarded too, there are heaps of variables left out (track temp? Warm-up laps on the semi's? wind direction and speed?) not to mention it's just meant to be entertaining.

Cars are complicated... and nothing is net pure positive (even those grippier tyres cause more friction when accelerating on straights). I've actually had more fun doing fine tuning and just driving my car the last 2 years... than I did trying to get it to work the previous couple without constant changes being made. Enjoy it and above all else modify the car in the way you enjoy, be it track times or aesthetics you determine whether it's a good or bad modification.

[deviant]

I think lap times only tell one part of the story. My car has got coilovers and a funky alignment, it might not be that much quicker than a stock one but the FEEL and the sharp reactions absolutely put a smile on my face every time I press on in it. With the coilovers the body feels much more controlled than with the standard springs and shocks.

I can see how the writer of the book would think the modifications make an MX5 worse if he has only dríven a car with poorly thought out modifications. Any car that needs everything harmonised and set up properly to be its best will feel terrible with a poor aligment or low quality tyres etc.

[gslender]

I always get frustrated when you hear car reviewers criticise a sports car for rough handling or being too stiff.... but then go on to say how awesome it is on the track.

I mean, every engineering activity in the world is a compromise - either a car is setup to handle great on B roads, or brilliantly on a flat tarmac track. Heck, at the extreme end of motor sports, the cars are individually setup for each track and event.

Anyone that tells you the "stock MX5" already has perfect handling needs to specify "for what"....!?!

[PaulF]

Anyone that tells you the "stock MX5" already has perfect handling needs to specify "for what"....!?!

Not to mention "which stock MX5?"

[project.r.racing]

This thread is totally stupid. Except the last 5 posts. No good comparing apples and oranges.