2011 MX5 Mod Options and their impact on Roadworthiness

[Dan]

Mate,
Purchase a gauge, drop the pressures to 30 psi (cold),

thanks Greg - whats a decent gauge recommended and easily available - don't want the cheapo inaccurate ones but at the same time can't afford the longacre 400$ ones recommended on this forum!!
BTW the door sill placard says 29psi, and i guess i got used to the 40psi skittish behaviour over time! Will drop to 30 and go up from there if needed. this is embarassing

They aren't that expensive, I've had one of the 'cheaper' longacre gauges for a while and it served me well.

You can get one from V-Sport for $61 posted to you ($46 + $15 postage) http://www.vsport.com.au/longacre-pressure-gauge-1879 and there are on ebay for $49 with free shipping http://www.ebay.com.au/itm/LONGACRE-520 ... 1174785252

[jassi]

thanks for those links Dan - those did not even show up on my google searches! I wanted something where the needle holds pressure reading until release so went with this one as it cost only 6$ to ship http://www.amazon.com/dp/B00GWTAAIA/ref ... 03980_n_id

[taminga16]

Don't be embarrassed, "Only the ignorant and the dead stop learning".
Greg. P.S. I have one of these and a foot pump.

[jassi]

Don't be embarrassed, "Only the ignorant and the dead stop learning".

thanks Greg! agreed completely there is a lot to learn

this weekend have been researching on the cost/benefit of going from stock to springs+shocks+sways(+maybe adjustable endlinks+bumpstops) vs just going an extra few hundred bucks and getting the ohlin dfvs i know the former is incremental expenses where-as the later is one shot, but if the end result is much better then thats worth considering! Ofcourse my street needs may not warrant coilovers and perhaps i should just get some progress springs for 200$ bucks and leave everything else stock what i am scared of is once I experience the springs I will want more and more till i end up spending as much as i would have coilovers anyway and this is what most people who eventually went coilovers say.

[taminga16]

jassi,
I would consider a decent alignment (front and rear) and some time in with the correct tyre pressures. Adjustable Whiteline sways would be the first mod.
Little steps. Greg.

[Dan]

this weekend have been researching on the cost/benefit of going from stock to springs+shocks+sways(+maybe adjustable endlinks+bumpstops) vs just going an extra few hundred bucks and getting the ohlin dfvs i know the former is incremental expenses where-as the later is one shot, but if the end result is much better then thats worth considering! Ofcourse my street needs may not warrant coilovers and perhaps i should just get some progress springs for 200$ bucks and leave everything else stock what i am scared of is once I experience the springs I will want more and more till i end up spending as much as i would have coilovers anyway and this is what most people who eventually went coilovers say.

I agree with taminga16 sways are a great addition, I drove my MX5 on the road and track for a fair while with just sways and enjoyed the car. If you want to lower it then springs are a cheap addition like you said and that along with sways I think is a fantastic upgrade for $800 or so in parts ($450 sways, $350 sprints).

Personally I wouldn't bother with Coilovers unless you really want to get serious on the track and I'd consider investing the money into enjoying the car at club track days, a 2k holiday or something equally fun

[jassi]

Greg & Dan - thanks for the wise advise!
yes have been on 30psi for the last few days - feels less skittish and ride feels more comfy. Will get to the alignment soon - will research alignment recommendations for a stock mx5 as well.
Agree on the springs and sways - that was my incremental (and wife friendly ) plan of action as well. However the math of doing incremental updates vs coil overs got me confused I guess.
For reference here is the reasoning I had put in the Ohlins suspension thread

The reason I'm thinking from a cost perspective is because progress springs (180usd) + koni (600usd) itself is 780 usd which is around 1000aud. Add some sways for 500aud, Fcm bumptops for 200 aud and adjustable end links for another 300 aud and I'm bordering at 2000aud already. If the Ohlins are available locally for 2700 aud and I can stick to stock sways then I'd rather spend the extra 700 and go down that path! Also I was thinking of buying from Goodwin for 1975usd on one of my US trips, but that translates to roughly 2700aud anyway and I still have to deal with customs and will have warranty trouble.

[jassi]

All in my search for headers, I came across the PPE catted headers http://www.good-win-racing.com/Mazda-Pe ... -0895.html

Would these be road legal in Vic, given the position of the cat and o2 sensors doesn't change at all as compared to a catless header (like gwr max power)?

Sounds fine from the vicroads modifications guidelines section 6.2 "for vehicles fitted with one or more catalytic converters as original equipment, the catalytic converter(s) must be retained in their original location and all exhaust gas must flow through the converters at all times. Similarly any sensors positioned in the exhaust system as original equipment must be retained in their original locations"
https://www.vicroads.vic.gov.au/~/media ... ashx?la=en

[hks_kansei]

Headers generally are acceptable for Vicroads purposes, and I see no reason that those ones wouldn't be.


The EPA are a lot stricter however, and when I asked them about a catalytic coverter a while back they basically told me that unless it's a stock one, or another brand that does the same as a stock one in every way, it's not acceptable.
In practice though, it's nearly impossible to be EPA legal, even an unmodified car often technically can fail (ie: the cat/charcoal canister/etc not being replaced as they wear)


Personally though I would say go for the headers if they are what you want. Vicroads guidelines are the main one to follow, since that's what covers RWC.

[jassi]

Headers generally are acceptable for Vicroads purposes, and I see no reason that those ones wouldn't be.

So vicroads doesn't really care much for the catted vs catless headers? If thats the case, then catless gwr max power seems like a a more universally accepted choice. I tried to search on the forum but couldn't find anything about people using the ppe catted header to be road legal.

Yes have been reading on other forums about epa and they do seem to impose heavy fines if caught going completely catless, but what if you leave the catcon in the midpipe? Will an mx5 nc with the catted midpipe (gwr or stock) along with catless header (gwr max power) pass emissions?

[hks_kansei]

I'd need to read the legislation again and concentrate on the cat parts.

It's only really been recent cars that have had cats as a part of the headers, so hasnt really been a problem before.


My gut feeling is that you'd need to keep a cat in there though, but obviously a gut feeling isn't law

[jassi]

hey Hks_kansei - quoting below the relevant section from vicroads modification guidelines. This made me feel a catted header replacement (like ppe) which keeps everything like the catcon and sensor positions similar to stock would be better. However I have not seen anyone on this forum go with the ppe. Mostly hear catless headers recommended here like the gwr max power headers. Both options still allow the midpipe catcon to do its job. So the question is, if normally roadworthiness is not impacted by catless headers (or undetectable), then does the midpipe catcon do a job good enough to pass emissions requirements as per epa.

6.2 Exhaust Systems
The following applies instead of Section 2.7 of VSB 14 Modification Code LA. Modified and alternative exhaust systems are permitted if they satisfy the following requirements:
-the exhaust system must not allow direct entry of exhaust gases into the occupant compartment
-for vehicles fitted with one or more catalytic converters as original equipment, the catalytic converter(s) must be retained in their original location and all exhaust gas must flow through the converters at all times. Similarly any sensors positioned in the exhaust system as original equipment must be retained in their original locations
-no exhaust system whether it be functional or ornamental is to be mounted in such a manner as to create a hazardous situation particularly from hot surfaces or projections
-all piping and muffler systems must be adequately supported
-exhaust extractors may be fitted to a motor vehicle manufactured before July 1976, provided they do not foul any part of the steering, suspension, braking or fuel systems. In all other cases, evidence either in the form of an Approval Certificate or acceptable evidence from the extractor manufacturer to show that the vehicle continues to comply with all applicable emission regulations will be required. Evidence from the extractor manufacturer is acceptable if it includes information:
1. identifying the extractors as appropriate for the particular vehicle make and model
2. certifying that the extractors have all the features and fittings necessary to allow the vehicle’s emission control system to be reconnected and work properly; and
3. describing how the extractors should be fitted
-the vehicle must continue to comply with the ground clearance requirement.There must be no escape path for exhaust gases other than the exhaust outlet, and the vehicle must continue to complywith the noise emission standards applicable to it.

[Dan]

A single cat will be fine to pass emissions, most cars only have one cat anyway.

Also police have bigger fish to fry than your car, don't stress and get a catless header.

[jassi]

Thanks for the advice Dan! Gwr max power n catted midpipe ordered waiting eagerly to have it on my mx5!

[Regie]

Good choice. That's what I'm running + rsq rear muffler.

The reason why u haven't seen anything on the ppre or chatted headers is cause they don't fit RHD cars.