mike323

I'm going to drop in a BP DOHC in my 323LX. The 323LX already has a BP SOHC. My goal is 140-150whp and still idle at 750rpms, trust me I can do this with about $1000Cdn ($720US).

I was thinking of going with a 2"mandrel bent exhaust with 2.25"high flow cat, since 2.25"is too much based on the experience I've learned with my 190whp PGT-ZE.

What's the stock size exhaust piping on the cars that have the BP DOHC?

Who makes adjustable cam pulleys for the BP DOHC?

What's the biggest bore I can do on my TB?

I can have my ECU programmed since I sell programmed chips for the KL engine for those with ZE engines. I'll be installing regrinded cams since I've done several for the ProbeTalk community and a set for the B6 engines. BTW my friends B6 miata produces about 132whp thanks to my cams.

If I shave the head 0.015-0.020"will this have an impact on cam timming, or does the timming tensioner takes care of all that?

zenilder

Stock exhaust is just below 2". 2" mandrel will be good. If you increase piston size and do any cam work, 2.25" will allow for more HP in the powerband.

Our ECU's don't accept chips, unless you're willing to desolder the chip and then solder in the new one.

You will need to adjust your cam timing if you shave the head.

If you install adjustable cam sprockets, reground cams, and a standalone, you might get near 130. To go any higher, you need to raise your compression.

If you're on a budget, you might look at MegaSquirt (I don't have the link right now, but do a google for it).
You'll have to go with a standalone if you want to make power. The stock ECU will do nothing for ya if you drop in some good cams. To reap the benefits from a good set of cams, you need a standalone engine management system.

I purchased a Wolf3D (http://www.wolfems.com.au). It won't be going in till I get my engine back from the mechanic. It's a great system. However, you'll have to search for good support. There's an e-group on yahoo for the wolf, either wolfems or wolf3d (I forget). There's a greater support base for the other EMSs out there like haltech. *shrug*
Read the info on the page. They have a manual and installation guide in PDF format that you can download and read.

mike323

I will desolder the stock PROM and solder a socket to accept a EPROM. I'm not that concerned about the programming part of the EPROM since I have a guy than is a genius.

How do I adjust my cam timing if I shave the head? Will the timing belt tensionner bring them back to spec?

I'm not that concerned about our ECU since the cams I'll be regrinding will be able to idle at 750rpms therefore not requiring complex ECU reprogramming.

mike323

I looked at the TB last night and it's about 57mm in diameter. I didn't remove it from the intake manifold so I couldn't take an accurate reading.

57mm is good for about 140-150whp without beeing a restriction, therefore I won't touch it.

BTW what's the exact measurement of our TB?

hotrod0001

Gro said that the TB was a 60mm unit.? Not to sure though.

zenilder

You can buy adjustable cam sprockets from NOPI and Toda.
If they're too expensive, you can take your stock cam sprockets to a machinist and have him convert your cam sprockets into eccentric cams. If you say that and he doesn't know wtf you're talking about, go to the next guy. I'm going this route. I don't need that much adjustability. I'll adjust my cams till I find the powerband I like, and I'll stick with that and it'll be done with.
What is an eccentric cam sprocket? If you take off the bolt holding the sprocket onto the cam, you'll notice a small dowel pin on the camshaft head, which inserts into the cam sprocket. The hole in the cam sprocket that the dowel pin fits into is enlarged so that it accepts eccentric keys. You can change the cam timing, with the keys, +/- 5 degrees. If you jump a tooth on the cam, you can adjust between +/- 15 degrees. This route forces you to check your timing.

zorlac7

cam gears for BP DOHC are available from: Toda, Flyin' Miata and Unorthodox.

mazdaspeedwest

I agree, i think you'll hit the 140ish mark. The BPDE motors respond very well to cams.

Braden produced 122whp with a stock 94 BPDE motor, a Haltek EK6 and a left over 3" turbo exhaust.

Not 100% but i think the tensioners will do it.

Manach

Was it ProtegeSTS, or ProSTS that once told us that the BP engine could be pushing 200whp. That was 2 Protege Rally, on a N/A Setup..

But, I would skip the head shaving, and go with Miata Piston.. 10:1 compression instead of 9:1, and the height of the head is the same for both piston.. so no trouble with the valves..

I see that you are from Mtl.. MazdaSly in 3-riv do pulley for eh BP engine for 300$CAN, crank + alternator.. Unorthodox solde there for 300$ PER PULLEYS!

For a 150whp car.. what I'll do is the following..

-Better exhaust, 1'' to 1.25'' per liter is good, so 1.8, that's around 2'' pipe. 2.25'' would be the limit. I would be doind it 2.25 all the way thought.. high flow everything..
-Better Intake, that include a TB enlargement, which MazdaSly also do.. and custom CAI.. I tested one on my Mx-3, and, I notice a gain at higher speed.. Also, I would switch the VAF/MAF to an RX-7 non-turbo 86-87. If you want one of those, I got them for 50$ + shipping..
-New pistons from a Miata 1.8 10:1 or 9.4:1
-Cams, but I am not a big fan of those.. As I see it, you can do them..