Improving the bottom end responsiveness of a stock SE

Nevyn72 · Postby **Nevyn72** » Fri Dec 20, 2013 8:16 am

So I've had my SE for nearly two weeks now and despite having very limited opportunity to drive it due to work being so hectic I'm getting a feel for what I like and don't like about the stock car....

Now I've been doing as much research as I can in my time off but am starting to feel like my head's about to explode from the info I'm trying to absorb!
So I need the help of the gurus around these parts to try and straighten things out a bit.

I've got a limited budget for this project so don't want to start spending money willy-nilly on mods that may lead in the wrong direction.
What I'm after is the best way to improve the responsiveness of this little beasty in the lower rev range.

Strangely enough, even in stock form, I'm quite happy when things get over 5000rpm but that's not where I spend most of the time, just want to cruise the country roads with the occasional blast for a bit of fun.

So what mods would I do to best achieve this?
Not after much of a gain in peak power, just want it to start earlier in the rev range and last longer.
From most of the dyno graphs I've seen most of the improvements seem to occur above ~4000rpm after modification.
Is it simply a matter of getting the turbo doing it's thing sooner, at lower rpm?

What bits do I need to replace on the standard car to achieve my goals?
I know a supercharger would probably achieve this but that's an awful lot of $$ and work!

Thanks in adavnce for your suggestions guys!

Lokiel · Postby **Lokiel** » Fri Dec 20, 2013 11:52 am

See http://www.mazda-speed.com/forum2/index.php/topic,29224.0.html for a similar query and response.

See tomli's ChipTorque mod for some useful info too: http://mx5cartalk.com/forum/viewtopic.php?f=57&t=61306&start=45

To make it cost effective though you really need to do all the supporting modz first (CAI+BC+Larger Injectors + Exhaust), then get the ChipTorque mod.

Personally I prefer an aftermarket ECU since it can be tweaked with each mod you make. The ChipTorque solution requires a complete update with every mod so it's best to do all modz first - and it helps immensely if you can actually leave your car with them so that they can create a custom-tune specific to your car, otherwise you may have to send the chip back and forth a few times to correct any issues.

Nevyn72 · Postby **Nevyn72** » Fri Dec 20, 2013 12:55 pm

Thanks Loki, I had actually seen that mazda-speed thread but had forgotten about it!

Also really interested in the ChipTorque solution as I want to preserve the factory good behaivior (WRT coldstart, electrical loads, AC, etc.), but eliminate the factory ECU limitations & issues and be set & forget. As I only plan to do modest mods and then 'leave it alone' this should suit my needs.

So basically do;
- CAI
- Intercooler
- Exhaust
- Injectors

Then get a ChipTorque reflash done.

I probably wouldn't even worry about upping the boost, only after modest gains after all, and certainly wouldn't hurt the longevity & reliability of the engine.

Do you think this would achieve what I'm after?
(Well at least until I lose the plot down the track and demand MOAR POWWA!! :mrgreen:

)

Postby **NitroDann** » Fri Dec 20, 2013 1:15 pm

The biggest downfalls are the factory tune, the airbox and the exhaust, and I recommend you up the boost to 12psi.

12 will be totally safe and make a lot more torque than factory.

The issue with higher than stock boost isnt the boost its the factory tune and the piss poor bandaids people use to attempt to run it on the stock unflashed ecu on higher boost with bolt ons.

Dann

Nevyn72 · Postby **Nevyn72** » Fri Dec 20, 2013 1:47 pm

NitroDann wrote:The biggest downfalls are the factory tune, the airbox and the exhaust, and I recommend you up the boost to 12psi.

12 will be totally safe and make a lot more torque than factory.

The issue with higher than stock boost isnt the boost its the factory tune and the piss poor bandaids people use to attempt to run it on the stock unflashed ecu on higher boost with bolt ons.

Dann

Thanks Dann,

So you recommend upping the boost as this will help low down torque?

Is the intercooler upgrade helpful, unhelpful or indifferent?

With your wealth of knowledge, have you any experience with the ChipTorque solution? Any thoughts?

Lokiel · Postby **Lokiel** » Fri Dec 20, 2013 1:58 pm

Those modz and 12psi will net you a safe ~150rwkw which is a hell of a lot of fun.

After you've paid for them, your wallet will be significantly lighter which will help temper you desire for "MOAR POWER" but it's a powerful calling and "Resistance is futile" so you too may get assimilated by "The Borg(-Warner)".

Regarding the IHI turbos and what's safe, I only know of the exhaust housings cracking at 14psi under hard track use so 12psi is quite safe, even if you do flog it from time to time.

Postby **NitroDann** » Fri Dec 20, 2013 2:11 pm

Nevyn72 wrote:
NitroDann wrote:The biggest downfalls are the factory tune, the airbox and the exhaust, and I recommend you up the boost to 12psi.

12 will be totally safe and make a lot more torque than factory.

The issue with higher than stock boost isnt the boost its the factory tune and the piss poor bandaids people use to attempt to run it on the stock unflashed ecu on higher boost with bolt ons.

Dann

Thanks Dann,

So you recommend upping the boost as this will help low down torque?

Is the intercooler upgrade helpful, unhelpful or indifferent?

With your wealth of knowledge, have you any experience with the ChipTorque solution? Any thoughts?

As simon said do those mods and up the boost, 150rwkw is around 180whp/tonne or over 200 crank hp/tonne

For comparison around 130whp/tonne for an LS1 5.7L commodore, 120whp/tonne for an evo7.

The best street MX5 I have ever dríven IMO is Yemin's SE with these mods and an AMAZINGLY perfect silky smooth tune.

The perfect tune is the key, so it comes down to what chiptorque can promise VS getting an adaptronic and having andy's personal dyno guys spend a couple days on it.

Dann

A.Chen89 · Postby **A.Chen89** » Fri Dec 20, 2013 2:17 pm

As above, your tune will only be as good as the tuner

emily_mx5 · Postby **emily_mx5** » Fri Dec 20, 2013 2:21 pm

first 2 "mods" should be a boost gauge and a wide band 02 sensor + gauge, to keep an eye on things.

Then its all the normal things, cai, bigger intercooler, bigger exhaust, bigger injectors, M/E BC, and (most importantly imo) a tune.

Nevyn72 · Postby **Nevyn72** » Fri Dec 20, 2013 4:03 pm

Thanks for all the great responses there folks, this was pretty much what I was coming to the realisation of due to my research.
It's great to have my thoughts confirmed, even if it's going to be a bit more involved and expensive than I had hoped......

Oh well.....

* Turns and faces the world.... opens wallet.... intones the sacred chant "Help yourself" *

kenson · Postby **kenson** » Fri Dec 20, 2013 7:24 pm

The sad thing is, nearly all SE owners go through the same thing in pretty much the same order (or very close).
I too have asked very similar questions. What most of us don't do, is go straight to the ECU, but a lot of us recommend it after all the fun/pain/frustration.

I've been doing it in stages over the last year or so and it's no different to what you'll hear here.

Dann's exhaust is the last "bolt-on" for me then I'll be looking at the ECU next year and hopefully have something like Yem11n/Dann describes.

I've gone through in order: Intake, BOV, boost gauge, MBC, injectors, O2 mod and diode mod. All relatively cheap stuff.
Exhaust and ECU will the last for a while. How long? I don't know :mrgreen:

Before all this I thought it was a good car. It only started going downhill when we decided to get a BMW 135i and I started motorsport with the MX5.
Don't get me wrong though, the SE is a good base. Just needs a few thousand dollars thrown at it!

[Edit] Plenty of good info here and very well documented here. Thanks all!

AndrewJZX100 · Postby **AndrewJZX100** » Mon Jan 27, 2014 2:41 pm

disconnecting the tps does a similar job as the o2/diode mod, could give that a go and see if it runs much different. Mine did, feels like it has an extra half a litre of engine its that much more responsive, and mines 100% stock. If nothing else it'll give you a guide as to what its like when the ecu isn't holding things back.

NB it'll idle at 1200ish and throw the check engine light on. I've done a few thousand kays like that cause the extra midrange is awesome haha, it's like the car should've been from the factory

WASP · Postby **WASP** » Mon Jan 27, 2014 5:09 pm

HI
Raise the boost to 12,how!
Cheers
Steven

davekmoore · Postby **davekmoore** » Mon Jan 27, 2014 6:17 pm

Lots of good advice already given. If you take note of it you'll have an awesome car for the street, where you only use full throttle for short blasts. If you start going to the track you'll use full throttle for a larger percentage of the time and will need more cooling.