Which BP into NA6

[DanZig]

Appreciate the knowledge sharing Magpie. I have watched over your thread for a while and am currently in the process of going through madjaks which are both great builds btw. If I wanted to remain fast and cheap I'd keep going with my turbo. If I wanted to go a lot faster I'd buy an Evo... oh. I don't expect to get anywhere near the same power and I expect I'll spend a lot more (turbo really is a bargain).

While I haven't actually taken on an NA build (other than just a stock rebuild) I do appreciate all the work and intricate little pieces working in harmony to create the wholistic package. That's what I find appealing besides the driving experience and sound. Since I've decided to head down the NA route I've spent the whole time worrying I had the wrong engine to start with as I did buy with the intention of building up another turbo motor haha. This is the start of my research besides the other many hours back searching.

Sounds great! Damn cool hill climb too by the looks of your other vids. Shame it's soo bloody far from SA.

[gslender]

I'm not against what others have done, just saying having built a SC in a 1.6 and then moved to a 1.8 with cams and ITB the difference is staggering. The later build that wasn't "planned" has turned out remarkably awesome. Perhaps that's luck, but a BP4W head, upgraded valve train and high lift cams with a decent amount of overlap with the standard 40mm trumpets on the Jenvey ITBs has turned out great!

I didn't engineer or match anything and just did some basic things using a normal approach. I've even used the less than popular MS3 ECU and that's been excellent too. I'd recommend it and others who have dríven her agree she's a wild track beeotch!

Just trying to encourage and ensure you don't get scared away in fear of taking a chance. If you lived nearby you'd be welcome to go for a spin.

G


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[DanZig]

Thanks Grant. Since I'm changing over to BP I needed to change over my turbo gear anyway so chucking in a cheap motor from the wrecker is a pretty small gamble. From there I'll just keep researching and prodding those with info. The ITB's seems like a bit of work but there's plenty of info out there.

I do wish I did live closer as I'd love to have a go and there's plenty of cracking cars in the other states. Most of the MX5's down here are pretty light on the mods.

[madjak]

Another suggestion is to do something similar to what I did... Run the stock engine in your car and start doing some basic motorsport events. Work on handling, brakes and develop your driving skills first. You might find the stock engine is more than enough to get you into trouble. Once you are comfortable with pushing the limits in cornering and braking, pick up a good second hand engine with a bit more power that already has had the development done. You can run this engine for a while and when your ready, rebuild it yourself to learn all the tricks and see how it was built. You can get some very nice 160+ whp engines for around the $4k mark if ask around... which will easily be half the cost of doing it yourself.

Either way, I'm a firm believer of just getting on and trying it. Don't be afraid to do something that you don't know, developing a car is a great opportunity to learn, especially with so much information around on the net. I really enjoy experimentation / pioneering something new as you can probably tell from by build thread. Some of things I've done weren't the best, but overall I've learnt heaps from my mistakes and I now have a car that's fairly unique and very enjoyable to drive. I'm very glad I didn't go down the turbo route, though I can't stop thinking about slapping on a Rotrex if ever I get bored.

Rick

[DanZig]

Great advice Rick, those are very good points.

I've actually been actively competing for the last 5+ years in khanacross, practice days, some drifting, spints and the various hillclimbs around the state. This wasn't my first track car either however, it did spend 2 or so years as a stock NA6 before I did my turbo and other mods and certainly a lot of my learning was done trying to push a slower car to it's limits. The last two years I've spent competing in my Evo 6 and while I've enjoyed it, won a few events but I do find the scene is a bit too dependent on money and it adds up fast. I plan on getting back into the MX5 for a while and working on my driving with a car that doesn't mask mistakes so easily haha.

The MX5 has always been a different philosophy of doing as much as I can myself and focusing on having fun rather than being competitive. Your second sentence touches exactly on my thoughts in this regards. I want to try something new and learn more along the way.

The turbo gear's off, the 1.6 is half our and I'll have that astina engine next week which I'll be throwing in essentially standard so I can go back, set a benchmark and work from there. Back to the slow class for me!

[madjak]

Back to the slow class for me!

Slow class is all about late braking and carrying corner speed... it's great fun as it requires so much commitment to put up a good time. When I was running the 1.6 I think I was driving far closer to the limit of the car than I do now, but I had so much more time down the straights to think about that next corner and set up for it. As a stock car, it was still awesome fun. With double the power it's a far more frantic kind of fun.

I love going out in my little MX5 and harassing the V8's, Porsches, WRX's. I can't get past them on the straights but I'm right up behind them under brakes and through the corners. It's very satisfying chatting to them afterwards when they see I have the quicker time and they ask if I have turbo rotary or something in the car... I wish there was a performance per $ spent class. I think the MX5 would be very hard to beat.

Btw, I have a 1998 Astina engine I just picked up. Going to try DIY porting it and start building it up as a spare engine. I'm not sure how far I'll take it but will probably keep it fairly stock initially (ie solid lifter, stock cams, stock valves). I'll take a photo of the head as the cam numbers are different to what I've seen posted here before bp11-2 or something ... it would be good to compare. Also I can measure my race head to see how much it was decked which is way more than the 60 thou you asked about earlier. It's decked so much that the timing belt is a little too slack with the tensioner at max, so I'd guess somewhere in the 1-2mm range.

[DanZig]

Yeah, I'm going to have to learn how to drive again haha. Evo's pretty forgiving with it's big power, grip and brakes. Nothing more exciting sitting right on the edge of adhesion trying to maintain as much speed as possible without ballsing it up!

Collingrove even the stock car was very competitive. Mallala does rely very heavily on speed and brakes however so most of the bullying only happens on prac days with the real green drivers. haha.

Back to motors and on BP's, that'd be great to see. While my NA8 (BP05) has hydraulic lifters I'm not really sure what the Astina will have seeing as it's a 96 which I believe is the year they went solid. Someone more knowledgeable can correct me on that I'm sure. Your race engine is a built NA8 engine no?

Quinn on clubroadster documented his experience though he was using a BP4W head on an on 02 block and went all the way to .100 thou and documented the belt being too slack for the tensioners which occurs after 60 thou. Not sure the height different between the motor components, something I will no doubt have look into. Many things I will have to look in while I enjoy stock life for a while.

[madjak]

96 is the cut off I think. I'm not sure how useful the shim over bucket lifters are anyway since big cams requires SuBs.

I think my engine runs a larger idler pulley from a Kia. It lets you deck the head further and brings the timing back a bit to compensate.

[3gress]

I know way less then basically all the previous posters however i think my own experience can add so.....
I started with a '97 astina sob engine, 9:1 comp, shaved the head 0.075" (1.905mm i think), put some toda 256/9mm lift cams in with mazda motorsport subs, supertech titanium retainers/springs and jenvey itbs. The valves were 3 angle cut, the ports were cleaned of dags and knife edged and bowls cleaned/ matched.
I ran it in my astina somehow managing to tune it with an adaptronic 440 uni with zero knowledge apart from what google told me.
The engine PULLS. I have no idea what it is pumping out and dont really care for figures, rather tangible increases. There is not a whole heap of cash invested for a poweplant that is more than capable as an all motor build. It pulled the astina along well and will only get better with the lighter mx5 and 10:1 nb block which is being prepared (thicker head gasket yo!)
I essentially jumped in the deep end and flailed around hard learning heaps along the way, meeting awesome helpful people and now have something in the shed that warrants all the effort.
Go for it and give us a yell if you need a hand or directions to a couple of youtube vids.
A basic recipe would include as much compression as you can get from a standard bottom end i.e. nb 10:1, spend heaps on the astina head getting it ported, cammed etc, jenvey and racing beat hanging of the mani' studs. I'm happy to recommend an adaptronic as the adaptive tuning/ volumetric efficiency tuning is well documented and easy to setup, mine started first go on a base map and its was apples setting up the injector dead times, accel enrichment (predictive something-or-other) and tuning timing and fuel maps.

[DanZig]

Sounds pretty wild 3gress!

1.6 is out and I'll be picking up the 1.8 Astina this week and just chucking it in to give baseline to start with. Next Sprints I believe is Feb so I'll be taking it stock (engine wish) to see how it goes. From there I'll be playing with the spare head I have and see where the road takes me! Who knows, I change my mind a lot haha.

ECU is a MS DIYPNP built by Grant so I'll be stick with that as I'm familiar with it and it does more than I need very well. Can't wait!

[Magpie]

Good to see the decisions being made, feels good doesn't it!

[DanZig]

I can finally catch up on that lost sleep!

[cookie]

Find a blown complete bp as you'll need sump, dipstick, engine mounts, I belive coil packs are different, intake manifold if not going itbs.

[project.r.racing]

He'll need the whole BP engine. Taking out a B6 and dropping in a BP from a astina/laser is a lot of work. All wiring is wrong. fuel rail is wrong. dissy does exist on a MX5, sump is wrong, water inlet wrong, water outlet wrong. Cam and timing gear covers wrong. And plenty I have missed.

[DanZig]

I do already have a complete engine from an NA8 and am aware of the differences.