Evo: GT86 VS MX-5

[strat61caster]

Originally Posted by DAEMANO

The presenter made a very clear point that the GT86's Primacy's contribute to it's both its' under and oversteer.

My personal experience is that the 86's understeer is suspension and alignment induced, adding grip reduces the oversteer and amplifies the understeer if no other changes are made.

But I'm just another fool on the internet.

[why?]

Originally Posted by strat61caster

An 86 'upgrading' to the same class of tire that comes on the Miata was worth 0.2 seconds around Willow Springs, the track that the ND came out on top by ~1s.

Skip to 6:00 to get to the point, note that the S04's tested are listed as performance tires, the S001's spec'd as OEM on the new MX-5 (same tire around the world so as tested in the UK as well) are listed as low rolling resistance per Tirerack.

Yup the tires would have put them neck and neck in this EVO test for sure, but the Miata has 83% of the weight and ~95% of the engine of the 86 and as mentioned in every video a much more competent suspension setup off the showroom floor (double wishbones give it a noticeable advantage in front end grip as explicitly called out in this video that the 86's front end is lacking in comparison). Tires won't overcome that in a test of handling as shown above where the 86 is on similar rubber to what the ND comes spec'd with (actually bigger rubber at 215 vs 205) and only get marginal improvements.

The Primacy's are seriously underrated.

The Miata is a great car, I'm not saying it isn't. If it came in a hard top and I could actually fit in it I would probably be buying one.

And tire "classes" are not good guidelines. So much variability even from the same tire manufacturer.

That is a great video.

[RandomDeception]

I remember watching a similar comparison video to that Mustang and BMW one a few months back where the car (FR-S or BRZ) became slightly faster than a stock WRX around a course once it put on high performance tires where beforehand it had around a 2 second disadvantage.

I can't seem to find it again though but it was probably compared to the older WRX with the EJ engine rather than a newer one with the FA20 engine.

[ajaxthebetter]

Obviosly at way different tracks, but at VIR, according to the new Car and Driver, the BRZ beats the Miata by 2.2 seconds.

But both were beat by a Jeep Grand Cherokee, haha.

[strat61caster]

Originally Posted by RandomDeception

I remember watching a similar comparison video to that Mustang and BMW one a few months back where the car (FR-S or BRZ) became slightly faster than a stock WRX around a course once it put on high performance tires where beforehand it had around a 2 second disadvantage.

I can't seem to find it again though but it was probably compared to the older WRX with the EJ engine rather than a newer one with the FA20 engine.

Road and Track, that 2+ second advantage was also seen in the video I posted as the Bridgestone RE11's, as well as the ZI SS in the road and track article were designed for competition use in various 'Street Tire' classes (SCCA, NASA, etc.) vs. the more road oriented tires sold as OE and used as intermediate steps in the comparisons. Also worth noting that both those compounds have been phased out and replaced by faster rubber (ZII SS and RE71R).

http://www.roadandtrack.com/car-cult...ransformation/

[RandomDeception]

Originally Posted by strat61caster

Road and Track, that 2+ second advantage was also seen in the video I posted as the Bridgestone RE11's, as well as the ZI SS in the road and track article were designed for competition use in various 'Street Tire' classes (SCCA, NASA, etc.) vs. the more road oriented tires sold as OE and used as intermediate steps in the comparisons. Also worth noting that both those compounds have been phased out and replaced by faster rubber (ZII SS and RE71R).

http://www.roadandtrack.com/car-cult...ransformation/

Thanks! So that was it; an article rather than the video that I misremembered.

I will have to thank your post for finding that once I have more than ten posts. :P

[thill]

Originally Posted by DAEMANO

Watching the video a few notes:

The cars as equipped for the test were essentially a draw at the track. The MX-5 is absolutely tiny inside with the top up and that body roll, wow. It was also noted that the Miata was optionally equipped with an LSD.

The presenter made a very clear point that the GT86's Primacy's contribute to it's both its' under and oversteer. In his words:

"the tires are made for sliding". "The GT86 will maintain a slide in a way the Miata will not". "The MX-5 will also slide around but you can't do it on power alone".

Most importantly the conclusion at 9:10:

"In the end just one tenth of a second separates the two cars. The MX-5 may be 40 horsepower down on the GT86, but it's much lighter and it has grippier tires. So the Mazda is the faster of the two just, but the GT86 was more fun. "

If the MX-5 gets an optional LSD upgrade then equal tires should be considered for the GT86 which would obviously make the 86 quicker at probably any track than this Miata.

First of all body roll is not a bad thing necessarily. At least not in terms of performance and ultimately the MX-5 is going to be more forgiving on bad roads.

I do agree that tires could have changed the outcome, but it is what it is. These are the stock tires that come on the various trims that the press gets. If you start modifying the stock equipment for a test then where does it stop?

Perhaps Toyota/Subaru could sell a "track edition" that has better brakes, lighter materials, better tires, etc.

[DAEMANO]

Originally Posted by thill

First of all body roll is not a bad thing necessarily. At least not in terms of performance and ultimately the MX-5 is going to be more forgiving on bad roads.

I do agree that tires could have changed the outcome, but it is what it is. These are the stock tires that come on the various trims that the press gets. If you start modifying the stock equipment for a test then where does it stop?

Perhaps Toyota/Subaru could sell a "track edition" that has better brakes, lighter materials, better tires, etc.

Didn't say it was bad, just that it was there in large amounts.

To your point, the LSD on this Miata wasn't stock equipment, it was optional and added for the test (just like you mentioned, where does it end?).

Subaru offers a BRZ Ts model which would be faster as it comes with everything you mentioned and all very similar to the U.S. Club edition MX-5 Mazda has been sending to the press in the USA. The BRZ Ts includes Bilstein shocks, 18" 225 section Michelin Pilot Super Sports and a Brembo BBK. Unfortunately, that car is only available in Japan ATM.

http://www.autoblog.com/2015/04/03/2...rz-ts-w-video/

Some quotes from the review

"I drove a few laps of the Suzuka's truncated east course in the standard BRZ before familiarizing myself with the tS (and, later in the day, running the full 3.6 miles of racetrack). For all the work put into improving lateral stiffness, the most noticeable change is the grip from the better tires. The added traction had me pushing harder and driving faster through the esses of Turns 3 through 7, and boosted my confidence carrying speed through the breathtaking Turn 15.

Where the standard BRZ's rear end gets loose with aggressive throttle prodding, the sticker contact patches on the tS keep the car in line at far higher loads.

...Overall the BRZ tS was significantly easier to control than the one that's currently on sale in the US. Especially because I was learning the track as much as the car, I noticed that mid-corner corrections were easier to execute in the tS, with high-feedback from the steering and chassis putting me in close connection with the rubber and the road.

'll admit, going into the day I was a little concerned that a stickier BRZ would be more competent but less fun to drive. I've always admired the way a bit of softness in the Subaru makes it more charming on real-world roads when more serious sports cars sometimes leave me cold.

I needn't have worried. I never climbed out of the cockpit without a grin stretching across the too-small Japanese-style helmet framing my face. The magic STI made in tuning this car, with the company's deep knowledge and team of 50-plus engineers, is that the is tS hasn't lost or changed the BRZ's essential character. Home-brew tunings may strike that same balance, but they're just as likely to upset it – yet another reason to get a tS clone stateside ASAP."

another review here: http://www.motortrend.com/roadtests/...s_first_drive/

[DAEMANO]

And an older comparison of fully prepped and tuned 270 HP Turbo NC MX-5 vs. a GT86 with TRD upgrades and most importantly Michelin Pilot Sport 3's. Almost no power mods as TRD only had intake and catback at the time. The MX-5 with impressive HP output and built suspension manages to be 1.8 second faster lap 1:10.7 vs.1:08.9.

Still for an 8 minute long video, the first 4 minutes the reviewer spends most of the time talking about the difference the tires make for the GT86, and then mentions it again at the end of the video. On this car, for lap times, the Primacy's suck and majorly hamper the car's performance. Good thing for us, that's a cheap and easy fix to an already very capable car.

Looking at Fastest laps, what looks to be a stock GT86 on Primacy's turned laps 2.1 seconds slower at Blyton Park (driven by Tiff Nedell of all people) 1:12.8 from the test above's "TRD" GT86 on MPS3's (1:10.7). Working on confirming the source. The Primacy HP tires handicap the 86 more than its' suspension configuration. http://fastestlaps.com/laptimes/50dc6427ab072.html

[Entroper]

I think I agree with both viewpoints: The Primacy tires ARE the biggest weakness of the 86, and they ARE underrated.

They are underrated because they happen to be available in one specification of the Toyota Prius, hence "it comes on Prius tires". That's not really a fair representation of these tires; they aren't comparable to your average all-season econobox tires. Yet, they aren't comparable to many UHP/MP summer tires, either, as evidenced by the various tests showing 2+ second improvements on ~90-second lap times.

So you guys are all correct.

[Rampage]

While the tires are undoubtedly an important factor in the two cars performance there are other reasons that the MX-5 may be quicker around a tight course and the twin faster on a long course.

Tthe MX-5 has a very flat torque curve which may make powering out of corners easier. It is lighter so braking distances will be shorter and cornering speeds may be even higher than the twin. All these would give it an advantage on a track with multiple turns and short straights.

On a long track, the higher HP and redline of the FA20 will come into play. The extra weight is not such a disadvantage once you get it moving and if there is less braking. The final advantage for the twin on the faster and longer course would be the superior aerodynamics of the coupe compared to the convertible.

I hope to see both of these cars mixing it up in the world of motorsports for years to come.

[Deep Six]

Rampage nails it!

[bfrank1972]

Originally Posted by Rampage

The final advantage for the twin on the faster and longer course would be the superior aerodynamics of the coupe compared to the convertible.

This, aero will be better on the 86. Makes a pretty significant difference on longer straights.

[Poodles]

Originally Posted by thill

First of all body roll is not a bad thing necessarily. At least not in terms of performance and ultimately the MX-5 is going to be more forgiving on bad roads.

I do agree that tires could have changed the outcome, but it is what it is. These are the stock tires that come on the various trims that the press gets. If you start modifying the stock equipment for a test then where does it stop?

Perhaps Toyota/Subaru could sell a "track edition" that has better brakes, lighter materials, better tires, etc.

Notice how the Miata (I'm sorry, I'm never going to stop calling it that Mazda) loses a lot of ground in the hard S corners? Lots of body roll makes transitions much harder.


The low CoG of the twins is also coming into play with the roll, it's not like the Miata is that nice on rough roads...


For some reason I can't quote DAEMANO's post, but the Miata has the option of the LSD from the factory while outside of Japan, the twins don't have an option for better tires.


I've been searching far and wide for track times from the tS with no luck. We all know the tS is going to be quite a lot faster than a normal BRZ, but I really would like to see the numbers...