…and then if you put in bigger fuel injectors to cope with Pmax, do they have the turndown ratio to cope with downtown traffic and idle or give good driveability on tip-in? Etc. etc.
Like you said earlier; simple engineering it ain’t.
As for BBR… not for me thanks.
I think the question many of us would have is, if one changes the manifold to a high flow, removes the CAT and then installs a new exhaust system featuring a high flow CAT, can the standard ecu make the most of such a configuration or is something needed? What about programming out primary catalyst?
Secondly, remaps sometimes have other fringe benefits like the fix for the throttle limitation in 1st and 2nd gear.
I’d appreciate your thoughts on both
Your 1st question is the 64 thousand dollar question. My answer is I don’t know…but I would love to find out. Somebody like DuratecNC is more qualified than me to answer that question.
What would happen if you ran the BBR185 hardware without the ECU remap? What exactly do they change in the NC BBR185 remap? I don’t know. Does anybody know?
With regards to the torque-truncation in the lower gears (yes, that really is the correct term for it), well, what can I say? Is it annoying? Yes. Does it make the car feel “flat” and underpowered? Yes. DId the OEM put it there for good reason or just to annoy us?
I suspect it was to make the car easier to drive and less snappy. Less oversteer prone
Not to protect the transmission?
NC transmissions seem to be very robust and are used in other applications that don’t have the same throttle mapping.
I wish you well. I have no ill feelings towards you but I think I am going to bow out of this thread, now.
All the best.
EE
Not sure what point you’re trying to make by doing so, but very well. I’m just out here trying to get some sensible answers. I’m genuinely curious about the choices Mazda made and why.
And why there are countless successful modifications of these cars without issue. Some being run in race conditions with members of this very forum. Is it a ticking timebomb? Is all tweaking liable to cause disaster down the line?
Does removing throttle restrictions have more to do with protecting the car, or more about protecting less skilled drivers? I don’t know, I’d love to have someone who knows the actual answer tell us.
You seem to come from a position of “all tweaks are evil and you’ll kill your car”. Maybe your right, i’m not qualified to answer that. But it would be amazing to hear from someone else who is qualified to make those kind of assessments.
There’s a whole business out there for car remaps, that seems to do quite well: are they all wrong? Are all their customers driving around on potential failures just waiting to happen?
I have no real horse in this race. My car remains Unmodified from an engine perspective and I’m on the fence about what to do next.
Your views on this have given me enough cause to be concerned and to want to know more. But there must be more to it than “don’t do it”
To answer some queries above
If modifications are done properly (not just to chase higher bhp numbers etc) then we have proven reliable where no harm will come to your car.
Re throttle mapping as an example
If a car is presented to me with good tyres then we can be slightly more aggressive than a car on toyo T1R’s if you can remember back to them lol
“Does removing throttle restrictions have more to do with protecting the car, or more about protecting less skilled drivers? I don’t know, I’d love to have someone who knows the actual answer tell us.”
Mazda seem to have other considerations other than power. This about the MZR…
“Between 3250 and 5000rpm the VIS valve is closed to maximise torque and produce a nice sound from equal length intake runners. Above 5000rpm to redline the valve opens creating shorter unequal runner lengths and altering the induction noise to become a more throaty rumble. In the UK the inlet manifold has extra swirl-control valves to reduce exhaust emissions at low revs and improve driveability from cold. Mazda says inlet restriction has been reduced by 57 percent and exhaust restriction is down by 40 percent.”
The Miata boys report that there are no swirl control valves in the States. Their 2.0 NC3.5 engines pull another 10 BHP. How much do I have to spend on exhaust upgrades to get that back?
Can’t the manifold just be replaced to exclude the swirl flaps?
As an NC3.5 owner, I’m keen to understand
This thread started as BBR customer service experience however as things move on and since we are talking technical.
IMHO the 2L duratec is a fine engine. power delivery is linear and torque is pretty flat - this is ideal. I’m not sure what the miata boys report but the stock 2L NC engine is around 160 bhp. and I’m pretty sure the California regs are much more restrictive than here…
If you use a single throttle body and stick with NA the inlet side of things is fine. Exhaust side there are a few different options but I don’t think there is a lot of difference between them based on the quoted power output (but I don’t have power curves to compare)
when you start messing with it (add high lift cams) “upsets” the torque curve at low rpm - so it wouldn’t be as smooth acceleration experience if you were simply cruising and lazy shifting the gears at that range.
and if you were to compare the 2.5L duratec with high lift cams powerwise isnt that much of a jump and torque delivery isnt as smooth as the 2L duratec (although there is a lot more of it)
At the risk of getting my head bitten off here, would it not be more cost-effective and easier on the stress levels to get a roadster that was designed for those power outputs from the very outset - like a Boxster or high-end Z4?
By the time you do the conversion to the MX5, pay more insurance, stump up when things go a bit (or very) wrong and generally take on the anxiety associated with an after-market conversion…
Genuinely curious. If my logic is wrong, I’m very happy to be (politely please) corrected.
bottom line…
Your car is now old. if the engine has seen better days it may expire if you try push it harder. I’m unsure if anyone can/will/is willing to guarantee your engine if you decide to modify your car.
If your engine is decent the experience modifying your mx5 is positive… (up until it breaks - expect that it will eventually break)
Does it matter? To me no. The car is a toy and I want to enjoy it. The smiles per £ I spend on the car totally worth every penny.
If an engine failure is going to break you then don’t do it.
BBR customer service can be a nightmare… (I didn’t but some people have), There are other options, for example Paul or anyone else. You could simply buy the parts from BRR and have them fitted elsewhere.
IMHO an mx5 NC doesn’t need anything else than what I already have done. A little bit of power with an awesome soundtrack from the engine and exhaust. Suspension wise your mileage will vary.
The car doesn’t really need a lot of power because the intent is to enjoy the thing daily without risking your licence. You don’t really need to go quicker on public roads.
If you want to go quick on track with an mx5 it be more expensive and I agree you could get something else that will be quicker - if being the quickest thing moving on track is what you want to do. But still managing the car with its limitations will teach you a lot of things… especially when you end up in the gravel trap facing backwards the barriers.
Modifying your car to your taste is also something personal and it would never be a cost effective exercise. It becomes a “project” that purely depends on the individual how far you are willing to go with it. Its all about the pleasure you get driving the car.
It’s a fair question! I modified mine (BBR 185) 6 or so years ago and asked myself exactly that at the time.
I went down the BBR route and kept the Mazda for a number of reasons - proper (not the artificial feeling) steering and an LSD is a good formula, good basic platform, good balance between low weight and in a vehicle that’s usable as a daily (versus say, MR2 that is similar weight wise but not as usable as daily…), a tonne of “how to” guides through various forums and on YouTube, modest parts costs, and forums such as this where you’ll find loads of members happy to share their experiences and help. To my eyes they still look pretty fresh for a design that’s quickly approaching 20yrs old!
All subjective clearly but this is how I justify spending money (that I don’t have!) on the MX5. 
Do you do the cams etc? I do miss the extra top end grunt from my tRUSTY ep3
Cams for which model? NC or ND?
Nd2 2.0 mate
Not at the moment
We do them for the ND1 but the ND2 with cams has much less torque so in reality it’s a slower car out of corners and only comes alive north of 7k rpm
I will be at the Mazda on track events throughout the year with a ND1 with cams
Off topic slightly
I do have a ND2 with a built engine and throttle body’s making 262 bhp
