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Discussion Starter · #1 ·
Well I hope this being my first post on here I hope will open up a good discussion as I'm looking for some advice for my two Mx5's. I was debating whether to split this over two threads but decided it be best to keep it to one to keep things tidy.

So I'm looking for some advice on both my track NA and my daily NC, Il start with the NA as that's the more interesting question I feel.

NA
So back ground to my question, I got into Mx5's thanks to racing in historic and while out on a track day around Goodwood got offered to have a go in a MX5 NA, there was nothing remarkable about this MX5 other than it running on Dunlop L sections. which is the tyre we race in historic. These tyres are still made just as they were in the 50s/60s old tec cross plies. though being a racing tyre they don't have much grip but the grip they do have is very consistent. once of the reasons you see these old cars four-wheel drifting. So this mx5 was a real joy running on these tyres so we thought perfect a great chance to have a cheap practice car that will go round a track all day long with little to no issues.

So we got ourselves a nice little NA stuck some Gaz coil overs, an exhaust system, and a decent clutch in it and headed out for some fun. The Tyres we put on it were Avon CR6ZZ on it as Dunlop L's are expensive and don't last very long so we figured this would be a good alternative. This tyre turned out not to be a great match as they were much sticker than Dunlops but still a good midway point.

Now on the track, the car is rather inconsistent and does let go suddenly with little warning. We have softened off the coilovers to try and get the car to behave more like my MG midget but this doesn't seem to help much. I know we are playing with a modern chassis and trying to get it to behave like a MG midget of the 60s so this might not be realistic.

So I put it to you all have you got any ideas on how we might be able to get our Mx5 to dance more like a historic.

Tire Vehicle Car Wheel Automotive design


I Loved that racer she was a joy to drive and although the set-up that it ran on which allowed it to cock a wheel like that wasn't the norm it really worked for me and I got some great results in that car, as well as got attention from commentators and spectators who would always find me and talk to me about how high it lifted its wheel. I would love my Mx5 to do that but I doubt it be a good idea and isn't possible lol but still I can dream.

NC
So I just brought a 2007 NC with 36k on the clock. body work needs some love, no rust but the old couple who owned it before me seemed to like cleaning it with a dirty sponge as well as bumping into things. I was also had over a little in that it was all supposed to be up and together but turned out that the front and back left hand wheels had buckled (think they must have mounted a curb). All sorted with some nice Ultralight F1 wheels nice.
The silver lining is it has the factory fitted suspension pack so an LSD, and Blistein shocks which they didn't advertise, happy days.
I do want to lower the car a little and feel the suspension feels good I would like it to corner flatter. It seems a shame to take off the Blistein shocks but same time would it be better to go coilovers. do you guys have any recommendations on a good path? lowering springs seem like an option but I don't want to ruin the ride as it is my daily. would an uprated anti-roll bar fit the bill or some chassis bracing? If the latter there seems to be a ton of options for chassis bracing whats worth doing?

Any help here would be greatly appreciated as well as interesting to discuss. I know car set-up is an art form as changing one thing affects another and to truly understand it takes a lot of learning. It's something I'm woefully ignorant about and want to learn more to apply it to road and track.

Thanks for stopping by, apologise for my writing and grammar moving forward dyslexia is a right bitch ;)

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Discussion Starter · #3 ·
Oh I they went to my introduction post?? That’s weird I wondered why you where talking about my question on that thread, just figured you had read it and jumped over to that one lol 😆
 

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Hi Rustang :)

I'm going to preface this by saying I am 100% not an expert and have no experience racing historics, however a couple of ideas come to mind. No doubt people who are way more knowledgeable than myself will be along in a bit to offer better advice, but here's my tuppence.

The NA was originally designed to replicate the "old school" Elan, Spitfire, MG experience, so my first point of call would be to put in a set of new original suspension. It was designed to be a bit wallowy, and it's a criticism of most modern owners, but it does replicate the "driftiness" of historics as would imagine them to drive (in my opinion). OEM suspension will raise the ride height however, so if you can find a set of lower springs with a complimentary spring rate that could drop it an inch or so. I am also going to say that lowering springs chosen poorly will destroy the handling, so if you can lower it without touching the springs then go for it. Depends on how good you are at fabrication. Alternatively you could look at a set of HSD Dualtechs which are supposed to be on the soft side, or OEM Bilstein's which will lower and stiffen the handling to OEM+ spec.

As far as tyres are concerned, 14" wheels provide the most pliable ride, but the high sidewalls also make the steering feel a bit spongy.15" is the generally accepted "sporty" wheel size, usually 195/45 section. The mx5 is picky about tyres and tyre pressures, with 26psi being a recommended pressure, lower than most cars. I run mine with 15" 195/45's at 28psi which helps it corner pretty flat. This is on Meister R's which are generally considered the creme de la creme of "regular" coilovers outside of race-spec Avo's and Ohlins than normal people wouldn't usually run.

The closest tyre I've used which could be compared to a crossply is the Pirelli P6000. It was an absolutely terrifying tyre in the wet on regular roads. It barely wore at all, was a rock hard compound, had spongy sidewalls and little in the way of grip, which is pretty much as I'd expect a crossply to handle. I'd never recommend them for fast road use, but on a track, trying to emulate old-school tyres, I'd maybe consider them!

Another thing to look at would be bracing of the car. NA's have a very wobbly chassis, with lots of flex, so I'd maybe consider stiffening it up substantially if you're hoping to cock wheels like in the picture! Skidnation do an underfloor chassis and butterfly brace which is supposed to really stiffen up the chassis. Likewise, there are frog-arm fender braces that help too, as will a cage of some sort too.

Other than that, I'd say pull as much weight as you can from the car, as well as consider a set of ITB's for the old-school throttle response you'd get from a set of carbs!

Like I said, others will come along and give you better advice, but this would be a good point to start your research from potentially!
 

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Discussion Starter · #5 ·
Cheers for the advice and some interesting ideas for sure. The cocking wheel for Mx5 is a bit of a joke as I don't know if it's even possible. but interesting ideas on the bracing as well its something I have thought about in the past and might look at again. It has Gaz Coilovers on it currently, I didn't buy these myself it was something that my old man picked out. We race together as well as do track days together, it's a shared car which he doesn't use that much anymore. I was wondering whether speaking with the manufacturers would be worth ago and going through what I'm looking for?
The only issue with that is most people I have spoken to about this look at me as if I'm insane and tend to shack their heads lol. why I thought about putting the question out here as I see a lot of peeps are passionate about car set-up.

The car is high up due to the tyres but I should really sort that by rolling the arches, the current Avon tyres are chunky side. I have a look into the P6000 too as I know it's a tricky thing as the Dunlops behave in a certain way in that their grip (or lack of) is constant and predictable. what tyre we try out as an alternative needs to share that otherwise, paddock hill could be very interesting :LOL:

as for ITB's I can not tell you how badly I would love to fit some of those not just for the response but the sound to.

You have given me some food for thought there :D
 

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No worries! Like I say, not an expert but I've been modifying and driving my NA for best part of 12 years now, so I'm familiar with what works well and what doesn't with it. You could certainly speak to some suspension manufacturers but for a custom set you'll be into some serious dough I imagine! The Gaz's are probably a really good set, but geared for flat handling and grip instead of slip angle, so might not yield the results you're after. On the plus side P6000's are pennies, especially in 14's so you could probably whack a set on and go at it without much to lose! Sounds like you're after a stiff chassis and soft suspension and low grip tyres which is the opposite of what most people are after so no wonder you're getting funny looks! 😂

As for ITB's, you know they make sense! I'll be getting a set of ZX10r throttle bodies fitted to mine in a few months time which will hopefully take me from 155bhp to somewhere in the region of 170bhp with any luck. And they sound brilliant of course which doesn't hurt!
 

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Discussion Starter · #9 ·
Maybe I can try and start a new trend ;)

This is definitely something to try, any bracing in particular. I'm guessing the chassis rails and front and rear bracing for the underside might do the trick? I have the roll bar fitted I'm sure that helps. as for the shocks and springs themselves like you mentioned that might be a little harder to suss out. I think you are right on building custom might be a little fanciful. giving fresh stock ago might be a decent idea just have to live with the high and see how it handles then play accordingly. I wonder if getting four-wheel aliment sorted and speaking with the right person and explaining what I'm looking for would help as well. I have to put up with the looks but hay hasn't stopped me so far :cool:

Four-wheel drifting space savers do sound epic XD, you just want a track to yourself and go at it and see what happens.

Is putting on a set of ZX10r throttle bodies a big job out of interest?
 

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No worries! Like I say, not an expert but I've been modifying and driving my NA for best part of 12 years now, so I'm familiar with what works well and what doesn't with it. You could certainly speak to some suspension manufacturers but for a custom set you'll be into some serious dough I imagine! The Gaz's are probably a really good set, but geared for flat handling and grip instead of slip angle, so might not yield the results you're after. On the plus side P6000's are pennies, especially in 14's so you could probably whack a set on and go at it without much to lose! Sounds like you're after a stiff chassis and soft suspension and low grip tyres which is the opposite of what most people are after so no wonder you're getting funny looks! 😂

As for ITB's, you know they make sense! I'll be getting a set of ZX10r throttle bodies fitted to mine in a few months time which will hopefully take me from 155bhp to somewhere in the region of 170bhp with any luck. And they sound brilliant of course which doesn't hurt!
do it for the noise, not the power.

What engine do you have that's at 155bhp?
 

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do it for the noise, not the power.

What engine do you have that's at 155bhp?
Same as yourself by the looks of things, VVT swapped NA! It's been a great swap so far, but now I'm getting a hankering for a bit more pep and the sound of course as well!
Eventual aim is to do headwork and cams to aim for the 185bhp mark. That'll be a skim, port and polish and maybe valves depending, but no bottom end work, and that'll do me I reckon as it's only for B road blasting. No track work for me!
 

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Maybe I can try and start a new trend ;)

This is definitely something to try, any bracing in particular. I'm guessing the chassis rails and front and rear bracing for the underside might do the trick? I have the roll bar fitted I'm sure that helps. as for the shocks and springs themselves like you mentioned that might be a little harder to suss out. I think you are right on building custom might be a little fanciful. giving fresh stock ago might be a decent idea just have to live with the high and see how it handles then play accordingly. I wonder if getting four-wheel aliment sorted and speaking with the right person and explaining what I'm looking for would help as well. I have to put up with the looks but hay hasn't stopped me so far :cool:

Four-wheel drifting space savers do sound epic XD, you just want a track to yourself and go at it and see what happens.

Is putting on a set of ZX10r throttle bodies a big job out of interest?
I've got a set of the underbody butterfly bracing from Skidnation to go on this summer after I get back from the NC500, so I'll be able to tell you how much of a difference if makes in a couple of months! I think maybe stock shocks and springs might help you get the softness back into the suspension that you want, and they're relatively cheap so it's not a massive risk to try them out. Four wheel alignment is a very good shout as they respond well to a good geo setup, but obviously do that after making any shock/wheel/tyre combo changes!

DanST engineering make throttle body kits for mx5's,and they are pretty much plug and play, bar needing a proper remap and tune. I've not purchased mine yet (getting married jubilee Sunday so am proper broke) but I've taken off inlet manifolds, fuel rails and what not before, and it's not a hard job to do. The ZX10r's aren't a kit on his site though. He normally only does GSXR throttle bodies, but luckily I know him through a very good mate of mine and he's said he'll do me some ZX10r's they've been experimenting with. Apparently they have more flow than the GSXR's so will net a bit more torque and power. Only downside is the oval trumpets apparently cost Dan an arm and a leg to make as they all have to be CNC'ed to order! Total cost is around the £1200 mark if you have a custom ECU and all the electronic gubbins to run throttle bodies, so it's not a bank-breaker. (y)
 

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Same as yourself by the looks of things, VVT swapped NA! It's been a great swap so far, but now I'm getting a hankering for a bit more pep and the sound of course as well!
Eventual aim is to do headwork and cams to aim for the 185bhp mark. That'll be a skim, port and polish and maybe valves depending, but no bottom end work, and that'll do me I reckon as it's only for B road blasting. No track work for me!
Interesting - what ECU are you running? you don't happen to have a dyno print do you?

I had originally planned to go down the ITBs route but having wrestled with multiple issues on the car, I'm only just now getting to a point where it's being tuned properly to bring it back to an OEM feel. My love for wanting to throw money at ITBs has dwindled xD
 

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Interesting - what ECU are you running? you don't happen to have a dyno print do you?

I had originally planned to go down the ITBs route but having wrestled with multiple issues on the car, I'm only just now getting to a point where it's being tuned properly to bring it back to an OEM feel. My love for wanting to throw money at ITBs has dwindled xD
I'm running an ME221 Gen2 on mine currently. Only mods engine wise are a stainless exhaust front to back with silenced decat, FPR, Wideband and Pipercross panel filter in the stock (drilled) airbox.

Dyno print is attached but it's on 95ron so a tad lower at 152.7bhp. With 98ron you get the full fat experience!
Speaking with Dan ITB's require a full re-tune, and I've heard they can be funny on cold starts when it comes to tuning, however my neighbour has an MK Indy with a set of Dan's ITB's on a Duratec 2.5L and he runs it all year round with them no problems, so I guess a lot of it comes down to setup in the end, like so many things! I'll be interested to see what figures I end up at, but the last VVT with a set on hit 165bhp and it was a weaker engine than mine so I'm optimistic we'll make the 170 figure!

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I'm running an ME221 Gen2 on mine currently. Only mods engine wise are a stainless exhaust front to back with silenced decat, FPR, Wideband and Pipercross panel filter in the stock (drilled) airbox.

Dyno print is attached but it's on 95ron so a tad lower at 152.7bhp. With 98ron you get the full fat experience!
Speaking with Dan ITB's require a full re-tune, and I've heard they can be funny on cold starts when it comes to tuning, however my neighbour has an MK Indy with a set of Dan's ITB's on a Duratec 2.5L and he runs it all year round with them no problems, so I guess a lot of it comes down to setup in the end, like so many things! I'll be interested to see what figures I end up at, but the last VVT with a set on hit 165bhp and it was a weaker engine than mine so I'm optimistic we'll make the 170 figure!

View attachment 60093
Yeah to be honest I was fully expecting around 160-165bhp on my VVT with premium petrol. I don't think it's unreasonable to expect that. I think you will easily attain the figures you want. Altho I think the gap between your two maps is what you want to see, a dyno bhp figure is after all dependant on the dyno itself.
 

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Yeah to be honest I was fully expecting around 160-165bhp on my VVT with premium petrol. I don't think it's unreasonable to expect that. I think you will easily attain the figures you want. Altho I think the gap between your two maps is what you want to see, a dyno bhp figure is after all dependant on the dyno itself.
I think standard is 143bhp so anything in the 155bhp zone is very healthy for a stock engine. The problem with these engines is they don't breathe and flow well, so anything you can do to alleviate that will help. From my research 185bhp is about the upper limit for a road engine that doesn't have bottom end work done to it. Maybe 190-195 at a push with a huge skim and high octane fuel but you're really beginning to push it at that point into the race spec engine zone! Unfortunately I didn't do a run prior to this work, but I'll be able to get a comparison once the ITB's are fitted eventually. PM me if you want any advice from my experiences! (y)
 

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Discussion Starter · #17 ·
I cant see cold start being an issue with ITBs, surely it's just a case of giving it a bit of gas when starting up. My racer had a single weber carb and is a fall race a-series and even on cold days, I can still get that darling to fire, just need to know how to treat her :p little tickle of throttle and she wakes up good and proper lol.

Out of sheer curiosity, I had to check if people have fitted twin 45 webers to these and they have, that's fantastic lol love that. seem tricky and pointless when you can put ITBs on there but still for the cool factor that's a load of fun.

For DanST doesn't seem too bad for what you would be getting, looks like the ECUs seem like they're a bit of money but that's not surprising.
 

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Getting a car to cock a wheel is 'easy' but getting a car to cock a wheel and not be an understeery mess is a bit harder. By 'easy' I mean you need to limit droop travel sufficiently and have soft enough suspension that the body roll is enough to reach the droop limit. The normal way of reducing droop travel (assuming that there's too much to start with) is to put a nice nylon bush inside the damper. Easy enough if you've got a rebuildable damper (Koni twin tubes are ideal for the process), but if you've got something that isn't rebuildable then you've got to do a fair bit of Frankenstein work to get at the piston rod. Don't worry unduly about the damper not being strong enough - it's only got to support the weight of the wheel + half the weight of the suspension arms and the damping force it has to transmit is way more than that.

The understeery mess is more of an issue. The 'efficiency' of a tyre in creating cornering force is inversely proportional to the weight on the tyre. You've got all the weight on the front tyre. Front tyres are trying to make you spin and rear tyres are stopping that happening. Reducing the efficiency of the front tyre will give understeer. There are ways to drive around the problem. Throwing the car at the corner is generally a good way... Engineering is a mixture of spring and damper rates - dampers controlling what happens on entry and exit and springs mid-corner.
 

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Discussion Starter · #19 ·
That does make sense dave if I'm understanding you correctly, the MG from the back is literally sitting on its arse when going through corners and lifting that front wheel. as much fun as it is to get that wheel to rise the main goal is getting the handling characteristics to be similar to the historic Midgets as I can, just down to wanting a car I can throw around brands hatch and get bum in seat time. nothing beats that for gaining confidence and learning tracks then going around and around, as long as you know what you're doing of course. The little A-Series engine in that car was producing 130bhp and raving to 7500 to 8000 rpm they only last a season (which for us was normal 6 race meetings) before they need rebuilding. so charging around in a historic all day isn't really an option unless pockets are deep. hence the 5

If she can four wheel drift and flows like these old motors I would have done it.

Oh and here is a rear view of the last time I got to go out in a MG, I think this is what you would call hitting the droop limit :LOL:. I stuck this up in my introduction thread but think its applicable here as well.
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I think standard is 143bhp so anything in the 155bhp zone is very healthy for a stock engine. The problem with these engines is they don't breathe and flow well, so anything you can do to alleviate that will help. From my research 185bhp is about the upper limit for a road engine that doesn't have bottom end work done to it. Maybe 190-195 at a push with a huge skim and high octane fuel but you're really beginning to push it at that point into the race spec engine zone! Unfortunately I didn't do a run prior to this work, but I'll be able to get a comparison once the ITB's are fitted eventually. PM me if you want any advice from my experiences! (y)
Appreciate it

I am really just throwing a VVT in with little work, a wideband and an MS3, ultra lightweight 1.6 fly and clutch, nb downpipe, mk1 mx5 parts exhaust.

I'm not expecting miracles from my tuning, I just want the car peppy and drivable in all weather.

If my turbo NB ever dies, it might end up getting turbo parts.
 
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