Rebuilding a NA8

[Haydos]

I am thinking about rebuilding my 1996 NA8 that has done 220 000km and is starting to show its show its age again.

I would like to do a little motorsport but am afraid that with its high Kms it will not last very long and it currently my daily drive.

My primary goal is to increase reliability but i would also like to increase the power. I have no interest in using forced induction.

I want to do a full rebuild of the engine, changing the exhaust, air intake and ECU. Has anyone done this before? Have any tips of compression ratios, size of pistons and cams. Need for wider wheels?

Any potential registration issues? I live in SA.

Or is it just not worth the $10k+?

[Bizi]

Have a look at Chris' NA8 Clubman build thread. Even though he's going turbo, it's getting all the bits you otherwise might consider and he's doing a thorough build thread. It's a great one to follow. look for zossy1 as the author of a garage thread.


Here it is: viewtopic.php?f=57&t=45260&start=60

Enjoy the read. GL with the research!

[NitroDann]

I am thinking about rebuilding my 1996 NA8 that has done 220 000km and is starting to show its show its age again.

I would like to do a little motorsport but am afraid that with its high Kms it will not last very long and it currently my daily drive.

My primary goal is to increase reliability but i would also like to increase the power. I have no interest in using forced induction.

I want to do a full rebuild of the engine, changing the exhaust, air intake and ECU. Has anyone done this before? Have any tips of compression ratios, size of pistons and cams. Need for wider wheels?

Any potential registration issues? I live in SA.

Or is it just not worth the $10k+?

See my build thread (NitroDanns long awaited garage thread).

Let me ask some questions.

What fuel will you use?

What rpm will you drive it at?

Do you have an lsd?

How much money are you budgeting?

Lets start from there.

Dann

[StanTheMan]

I am thinking about rebuilding my 1996 NA8 that has done 220 000km and is starting to show its show its age again.

I would like to do a little motorsport but am afraid that with its high Kms it will not last very long and it currently my daily drive.

My primary goal is to increase reliability but i would also like to increase the power. I have no interest in using forced induction.

I want to do a full rebuild of the engine, changing the exhaust, air intake and ECU. Has anyone done this before? Have any tips of compression ratios, size of pistons and cams. Need for wider wheels?

Any potential registration issues? I live in SA.

Or is it just not worth the $10k+?

Not sure If I agree with that totally.
My engine has done 10k km in the NSW Production sports. over 4 seasons. The car itself has now done just over 270 k km.

of course if the engine seems tired. it may quite well be tired. It just depends on how its been treated in the past. If the oil has been changed religiously..... you might find a rebuild.....a waste of time.
Of course if the engine is tired with 220 k km...its tired. Which means the car has been hrashed & not looked after well.

If I was to do it all over again.
exhaust & extractors
FULL air intake though firewall
Tighe 805 or similar profile on the standard cam sprockets.
tORSEN.
agressive 205x50/15 Tyres with decent shock & suspension geometry.
suspension bushes
don't worry about a ECU
Thats all you need. to make it go hard.
of course you could take this a lot further & spend an untold amount money rebuilding an Engine & having i tuned by a pro. and yes you will get slightly better results prolly 10-15 RW KW. But there are headaches involved in that to get it perfect.

If you want to do it propper. Its going to cost mega $
Do it Dodgy with a few bolt ons. It will go hard. If you go as far as a 272 profile your Standard ECU will be able to cope. But only just, at idle. But she wil recite poetry on 5 k & above. & the looks at the traffic lighst LOL......

[Haydos]

Don't get me wrong. It still runs really well, just it burns a little oil and it needs new oil every 5000km, which I give it. It has had a full Mazda service history and dríven by a middle aged woman until I got my hands on it 19 months and 30000km ago. Since then I have taken over doing the servicing, mainly so that I can use it to learn. I have changed the oil and filter every 5000km and do everything else it needs. I have installed yellowspeed coilovers because the old shocks were leaking and the springs sagging. I am 22 and as such give it the odd thrashing through the Adelaide hills and tear off from the lights occasionally. I mainly want to rebuild it so that I can hold on to it indefinitely, keeping in mind I won't be starting on the rebuild for at least 12months and I do a lot of kms in it. I have only done one motorkhana in it and it seemed to hold up okay, just I have heard horror stories of what motorsport can do to standard street cars and wanted to do the work now to lessen the chances of engine failure.

[NitroDann]

Ive never ever heard of an na or nb that died at the track due to not taking the punishment. Relax. It will be just fine.

Dann

[StanTheMan]

Don't get me wrong. It still runs really well, just it burns a little oil and it needs new oil every 5000km, which I give it. It has had a full Mazda service history and dríven by a middle aged woman until I got my hands on it 19 months and 30000km ago. Since then I have taken over doing the servicing, mainly so that I can use it to learn. I have changed the oil and filter every 5000km and do everything else it needs. I have installed yellowspeed coilovers because the old shocks were leaking and the springs sagging. I am 22 and as such give it the odd thrashing through the Adelaide hills and tear off from the lights occasionally. I mainly want to rebuild it so that I can hold on to it indefinitely, keeping in mind I won't be starting on the rebuild for at least 12months and I do a lot of kms in it. I have only done one motorkhana in it and it seemed to hold up okay, just I have heard horror stories of what motorsport can do to standard street cars and wanted to do the work now to lessen the chances of engine failure.

Thats sounds great. Although I havend heard or dríven your NA8. My bet the engine is in pretty good shape. I wouln't take it apart just yet. Do the bolt ons first & enjoy it.
Ideally, If you really want to do it properly, you need to know exactly what you want to achieve to get he maximum out of your BP engine. Camshafts, valving, type of porting an so on, need carefull consideration to make sure they match the flow. (read $$$)

very few engineers will build solid engine as well as the factory. If they do....will comand thier price. If hey are that good they are probably making better money building F1 engines anyway.
Yes we've seen some fantastic work here from some of our members too. The difference is though They also have passion for it because its thier own.

If I was to do it. I'd leave the current engine intact for some time. Rebuild a differet engine which really needs a good rebuild. Learn in the process & then transfer the bolt on bits when the time comes.

[Mr Morlock]

sure racing a car places a lot of stress on components- multiples of road use. Racing can be a lifetime hobby for some but it can also require a fair amount of disposable income. The car you described also suggests it is far from perfect- get a comp check to verify. You probably have to find out yourself perhaps by taking the cheapest route and see if it is a whim or a longer term passion.

[project.r.racing]

if you rebuild it back to stock specs, but use mild aftermarket cams like the Tighe 805s or Maruha F cams, you'll net yourself an extra 10kW at the wheels. should cost max $3500 (including cams) if someone else is doing it. or max $2500 if you are doing it.

I recently brought F-cams and gears from Maruha (which use paypal in USD) for $1100, when the USD was like 1.02 vs ours. now it is like 1.06-.09. purchase them seperately to avoid import duties and GST.

of course if you are rebuilding it, the sky is the limit, add:-

polish and port head = $500
bigger valves = $350
11:-12:1 pistons = $600-$900 depending on brand/compression
hone/bore block = $250
ecu + fit + tune = $2000
(workshop costs)

all for 30-40kw gain?

and there are little things like main studs, head studs, valve springs etc that all add to the final cost also.

[NitroDann]

More like an 80kw gain depending on cams and fuel.

Dann

[Haydos]

I had priced what i think is most things i want to add, including a new exhaust and cold air intake at almost $10000. For the renewed feel and extra power i am willing to spend that sort of money. I will be doing most the work myself, obviously trusting the machine work to professionals.

List of products and prices mostly from Mx5 Mania

Gasket Kit 400
Timing Belt 85
Spark Plug Leads 75
Spark Plugs 18
Con Rods 1550
Pistons 895 (from)
Tighe Camshafts 695 (from)
Fuel Filter 45
Oil Filter 15
Adjustable Cam Gears 180
High Output Fuel Pump 275
Head Studs 275
Hoses 295
Thermostat 40
Water Pump 95
Oil Cooler/Filter Relocation 450
Cold Air Intake 285
2.25" Cat Back 650
Headers 480
DBA Gold Brakes Front 385
DBA Gold Brakes Rear 313
Bendix Pads 184
Heavy Duty Clutch 615
Adaptronic ECU Package 1591

Total 9891

Anything missing or anything i shouldn't bother with?

[NitroDann]

Ill start by saying many of those prices are very high to say the least.

The vrs kit is expensive.

The con rods are close to 5 times too expensive.

The hoses are 290! Made of gold?

Dont do adjustable cam gears.

Go bigger cams than that.

Go solid lifters.

Thermostat is double priced.

Pistons are not nearly cheap enough.

Dont bother with fuel pump.

That exhaust price is at least 200 dollars too much.

Headers can be had for half that.


Dont buy new leads just upgrade to COPS.

And the ecu cost mightnt be too bad if it includes a full service including tune with all the mods.

Dann

[Haydos]

Okay so where can i go to get the things that are overpriced? Should i upgrade the injectors and throttle body?

[Dweezle]

Have a look at 949 racing.

[NitroDann]

The injectors will not need upgrading, they will flow enough, if you manage to make enough power to outflow them a cheap ebay adjustable pressure regulator would be a good place to start.

A 55mm throttle plate (na6 is 55, measure the na8 for reference) doesnt become a measurable restriction until its asked to flow aprox 210 rwhp, at atmospheric pressure (ie this rule isnt accurate when boosted). In other words, the throttle body is a wasted upgrade. This is the case in, id say, over 90% of throttle body upgrades ive seen across all car models.

Repco will sell you hoses for MUCH cheaper than that, and the internet will bring up even better prices.

Look at supertech forged pistons (400 odd from memory).

Look at M tuned rods for 300, forged and tested to 600rwhp reliably. Many many guys run them at 400rwhp every day.

A megasquirt ecu, with a map installed from tgeir database is doable for 500 odd dollars without any specialty skills, this will leave you with a car about to be safely dríven to a dyno shop. Then it should only need about 300 dollars of dyno time to get it spot on.

Headers come up on the forum for sale second hand all the time. They dont wear out so buying second hand is fine.

Cam gears arent needed as they are used to dial in cams and get the timing perfect. If your going to pay 1100 for cams (was it 600 each you quoted? Cant remember) youd wanna damn well hope the manufacturer has already ground them with timing for the best power, otherwise they are a useless company. IE, the hks engineers take offense that people buy their cams AND cam gears as that implies you can do a better job at timing them up than HKS can! Theres a reason tomei dont sell you cams and cam gears.

Solid lifters can be had for a great price from miata roadster.

COPS (coil over plug systems) are where you replace the factory pair of weak coils and inefficient leads combo with 4 coils that all sit straight on the plugs with a direct connection.
I will soon have a system for sale. It uses coils that lexus find fit to fire their V8s and their 2JZ engines. They will be no more expensive than really good leads and their performance really is soo much better than that. Even in very high boost applications (30psi+) or alcohol fueled high compression high rpm combos (E85, 10.5;1 and 8500rpm) like my na6.

Is there anything else I can help with?

Dann