zenilder

You won't be able to do it with the stock ECUs (LX or GTX) so you will need a standalone system. I'm partial to the Wolf3D from Wolf EMS, but others here like the Haltec hardware.

It's a matter of whether or not your engine can run at those revs. Stock, our engines will have a bit of vavle float once you reach higher revs. As Jesse mentioned, stiffer springs and solid lifters, like those offered from Toda Racing, will help reduce valve float. Fuel injectors and ingition became a hampering factor as well once you reach higher revs; however, if you use a stand alone, you've covered your ingition problem, and it's only a matter of making sure the fuel is squirted into the combustion chamber in a timely matter. Like Jesse said, we can get 8000, possibly 8500, out of our engines.

m2cupcar

Bryan- are you sure you want to go the NA route? The return on your money spent won't be nearly as good as going with boost.

That said- I can speak on my experience going NA with BP as I've done it. I built 2nd gen Miata BP using a stock bottom end - balance/blueprint only. I used the OE 9.5:1 pistons. Power was made through milling the block and head to produce just over 10:1 compression and modding the head with a lightweight valve train, solid lifters, cams and cam gears. Also added was a progammable ecu and high flow pump. I stuck with the stock (230cc) injectors and they were fine. On the dynojet, finely tuned (lots and lots of dyno time) the car made 142 ftlbs peak at 4250rpm and 154whp at 6500rpm. The motor was abosultey badass - and absolutely expensive (fortunately I avoided paying for everything).

Here's a breakdown:
custom cams and Mazdacomp EP valvetrain (spec'd by rules): $1600, cam gears $350, LINK ecu $1000, fuel pump $165, machine shop work $2000, and hours and hours of dyno tuning.

Keep in mind that the BP motor isn't engineered as a high-power NA motor, but as sturdy motor capable of handling boost. So you're embarking on mission that's contrary to the engine's design. The 2nd gen Miata motor shows Mazda's move towards better NA performance in the BP as they added higher compression pistons, re-engineered head ports, a solid lifter valvetrain, more agressive cams and eventually variable valve timing. Your older BP doesn't have any of this and that's a deficit you'll be working against during your build-up. You'd be better off starting with the most recent iteration of the BP- but then you'd also be faced with converting it to work with a fwd car- another project in itself.

I don't want to ruin your aspirations with this project- but I think you're going to be dissappointed with the results given the time and money it takes. And in the end if you do manage 200hp NA, it's going to be virtually undrivable on the street even with an ecu. In effect you'll have a race car motor in your street car. Whereas a boosted motor is just like stock at idle. It's not an "animal" until you're in the boost.

rob

m2cupcar

The hp is believable - but without cams the torque figures will be lacking compared to going with ecu, cams and adj. gears. Without the torque, the car will feel slower and be slower. - rob

m2cupcar

The run actually looks impressive w/o any engine mods beyond stock. Here's what the head cams, gears, ecu and deck did for my BP.
dynosheet

beachnut

Well, it sounds like letting that Gude racing head kit go by (the one for sale on eBay) was a good decision. I think I'm going to forgo the camshaft upgrade too. Anybody want to buy some AEM adj cam gears?

zenilder

Rob,

Thanks for the input. I really have been torn between boosting it or building it up.

I just don't want to deal with all the turbo mojo right now, which is mainly due to lack of finances and time (to plumb all the IC tubes and related mess).

Plus, doing a NA is something I've been wanting to do. From your figures, yeah, I prolly won't hit 200hp nor would I like how it would run if I were to attain those numbers. ~150hp at the flywheel will satisfy me quite well.

As of now, I'm still waiting on the engine because my mechanic has a number of jobs on his plate; however, he has replaced the rod/main/head bolts with ARP hardware, the block has been cleaned and bored to take the 2001 10:1 comp pistons, and he'll be modifying the stock cam gears to be eccentric. I am on a bit of a time crunch so I told him to just check out the cams and see if I can gain anything from the "15 hp" cams I have over the stock ones. I may ask him to look into the cams a bit more and see if a regrind of the stock ones will present a greater advantage over the "15 hp" ones. Oh.. We also agreed that the oil pan could use some baffles so that will happen, too. I wanted him to take a look at the head to do a bit of fine-tuning work/grinding, but that will take more time. dunno... I might stick with that route depending on how things work out (mainly time). The head is ported and polished nicely so I'm sure there would be less restriction as compared to the stock head.

I would like to eventually do a turbo BP or even a overdone B6 like Cam put in his Festiva (wicked engine). Not sure if I would move the NA over to another car and drop the turbo into the Pro, or I would just drop the turbo into a '91 Escort LX Wagon *evilgrin* :D :wee:

Either way, I just want to do the work to gain the experience. :)

thunderb0lt

Hehe.... u familiar with the story of the fox who finally consoled himself by saying.... "ahhhh f**k it... those grapes are probably sore anyway"?

Send me a PM with info on the Cam gears. Pics would help too.
Thanks

beachnut

I dunno yet thunderbolt, I'm having some second thoughts

Question for all: Should I really get rid of these cam gears? I've given up on any NA buildup like Zenilder is doing. I will go turbo at some point, either bpt or bolt-on, but that will be a while b/c of financial reasons. Until then I haven't totally given up on getting some Corksport cams (Todas are out of my price range). They seem easy enough to install and I would think I'd a least get *some* gain, esp with my intake and possibly a header. SO, my engine performance mods would look something like this:

- my existing PRM intake & RX-7 VAF, plus new mazdaspeedwest custom intake piping

- my existing Borla muffler, plus new Genie header, free flow cat, resonator, 2" mandrel pipe all the way

- my existing AEM adj camgears (though not installed), new Corksport camshafts, and time on the dyno tuning it right

That would be it for my engine/drivetrain mods. After that I can work on the suspension stuff and brakes. What do you think? Will that plan probably get me as much as I can get out of the car without going turbo?

m2cupcar

It's not so much the cams, the gears, the ecu, the built bottom end and head... it's the high compression pistons or extensive milling to build compression that will leave you stuck with a NA build up. If a NA BP build were to stick with 9:1 compression it'd still make good power (see the chart Jesse posted) and there'd be an excellent foundation for boost in the future. Nearly everything that goes into building a strong NA motor will pay dividends once boost is added. But I gotta say that you need to weigh the expense of the NA parts against a boosted setup and the return vs. $. I'd say that the primary reason for going with a high power NA setup is because the "rules" require you to, or for the desire to have a screaming four banger. My point was that a _high-power_ normally aspirated setup will produce less power and be less "driveable" than the similar funds spent on a boosted setup. - rob