To moze pozwole sobie wkleic email od jednego z forumowiczow astina gt (nowozelandzkie i australijskie forum mazdy – astiny).
well i auctally built my motor on the "cheap side" i wanted to use only OEM parts and use what i had lying around
engine rebuild and parts totalled $800 NZ dollars or $550 US dollars so very cheap for the power it made, i did 90% of the work and im really pleased with out much power it made using stock internals.
heres a parts list for you
1996 Mazda BA lantis / 323 BP engine, from a Automatic model
take the block to bits and put some Astina GT (pre cat pistons in) 9.8:1 CR, put race bearings in etc at teh same time
get the block blanced and conrods shotpinned for any weaknesses
I used a 1994 Mazda Lantis / 323 , Jap spec head
take the head to bits
remove ALL casting lines and port match the head to the gasket, ie NO lip
do the same for the inlet manifold, port match it and clean up all the casting lines in the VICS area too
Polish these both so you can eat off it, but give a tiny amount of roughness just before the valve seat, helps tumble the air into the engine
I used the valves from a 1996 Ford Laser KJ2 ...323F BA really.
Get the valves and remove all carbon build up, then polish them up, get some valve grinding paste and reseat the valves to the seats, to give a perfect seal, these valves have a perfect 3 angle setup from factory
the Valve springs ,valves and retainers are DIFFERENT to other BP engines of the BG and early BA
these heads have everything but Solid lifters, but solid lifters are only good once you start to go over 7500rpm
now the cams from the later model BA engines suck, some models have high lift but small duration, and duration is whats good for top end
take the BP06 exhaust cam from a BG Jap spec engine
take the exhaust cam from a BG 323f precat engine, cut the dissy drive off with a hacksaw
get some adustable cam gears, or redrill the cam gear to 197.5 degress clockwise from the " I " symbol
get it done from a engineer, 3-4 degress out will change your power band too much
put these cams in , but clean out the HLA /lifters first
now the exhaust system is where this setup hit its limits, i was using the OEM cast headers
Headers; if i had the money i would have got a 4-2-1 to 2.5" outlet then i'd let it go down to 2.25" to the flexy then right the way out again
reason..2.5" all the way will cool the exhaust gases too fast and give very crappy low end power, so to get the best of both worlds, a 2.25" from the flexy back will give great power all over the show
cold air box, sure could be use full. 1-2 hp increase maybe, a cold air box can give good low end but not much uptop, so less HP,
so a open air POD filter in a air surround is better
Lastly is the ECU, one person in the US is making 145whp using stock ECU, but he runs higher CR pistons and has custom exhaust and headers
i used a Link G3 EMS, but it made the same power as my factory Astina GT – precat system, so ive keeped that instead
to get 138hp at the wheels from a 140hp at the flywheel engine takes some plaining
Revs = HP
but torque is the power
long story short my engine had peak power at 6500-7200 rpm...the torque band did not fall off after 6500 rpm..but it didnt go up either,
the reason it didnt go up is simple..the engine was now choaking under its own air flow, the exhaust system was now a restriction (standard exhaust manifold)
so if i had fixed the exhaust system, the peak power would have shifted up higher to say 6800rpm , and given me a extra 5-8whp (more revs more HP )
loosing engine internal mass/weight is also another big part
i used a crank that wieghted 12kgs vs the 16kgs version on the normal BG BP1800 engines
this allows the motor to have a more free sprited feel, and not have to work so hard when reving to get its selve moving, same rule applies with lightening the flywheel and if you can afford to get custom light weight Pullies/Harmonic balancers (careful on the oil pump some will kill it)
only problem with the light internals is the engine doesnt drops its Revs as fast..so trying to do fast gearchanges makes it hard to go into gear..its fixed if you can double clutch it correctly, i tried...i just gave up and started to slam it into gears instead
of course all this PLUS
11:1 pistons
light conrods
272/9.3mm lift cams, cam gears
Link EMS
MX5 2000+ head would = 160=175 whp
but will cost 3-5 times what it cost me to build it
Nie chce mi sie tlumaczyc, bo duzo tego tekstu. Generalnie obrobka glowicy, CAI, kompletny wydech (kolektor , tlumiki przelotowe) + regulowane kolka rozrzadu powinny dac tak jak u niego ~140koni na kolach, czyli jakies 160koni na wale.