OBDII DOHC engine

projectmx · Post by **projectmx** » June 20th, 2005, 12:26 am

does anyone know anything about the obdII version of our dohc 1.6L engine i've head it has more hp than the 94-95 engine... anyone know anything about this engine?

Thunderstorm · Post by **Thunderstorm** » June 20th, 2005, 9:45 am

I may have the engine you are talking about.
My 1998 RS 1.6i DOHC engine delivers about 108bhp - 110bhp.
The sales brochure (UK 1997) quotes 110bhp.
I have seen 108bhp bandied about in other journals.

I actually have a copy of the above mentioned brochure (ordered from Ebay) which I hope to scan and pass on to mx-3.com as soon as it is possible.

My 1998 RS also came with disc brakes all round, 15 inch alloys and 195/60 15 Tyres.

projectmx · Post by **projectmx** » June 20th, 2005, 9:53 am

bhp is less than wheel hp right? i recall in a few posts people saying that it might be even more than the 110 hp... i'm kinda considering trying to find the engine you have with low miles and swap it into my car so i can have an obdII engine plus a few extra hp and still say in the same autox class. do you happen to know what changes were made to get the extra hp? is it just computer work?

Devilhog · Post by **Devilhog** » June 20th, 2005, 11:11 pm

I know my 96 RS DOHC isn’t OBDII. I used to work for a company that made OBDII testing units that you could connect to remotely and see how the car was running (and much more cool stuff). I was told that 96 and after domestic cars/trucks all have OBDII but that rule/restriction wasn’t introduced to import vehicles.

Ended up looking at my car to see if we could connect to it but was out of luck.

Hey but I had a free GPS tracking unit for a year

Always nice to see where my brother takes my car when he borrows it mwhaha

Flashpoint2 · Post by **Flashpoint2** » June 21st, 2005, 4:17 am

That's interesting, i was told that mine IS OBDii, and I have a 96 RS as well.

Tonestire · Post by **Tonestire** » June 21st, 2005, 9:18 am

I thought 95' and up were OBDII?

projectmx · Post by **projectmx** » June 21st, 2005, 4:15 pm

all 96 and up should be even my 95 protege was but i doubt any of the 95 mx-3's are...

.... but that is beside the point does any one know any real info concerning the power difference and what changes were made in the second generation of the 1.6L dohc's in the mx-3?

Devilhog · Post by **Devilhog** » June 21st, 2005, 8:21 pm

Nope, mine isnt, the techs at work looked at it. They were testing all the co worker's cars so they wouldnt have to rent those brands for a day.

projectmx · Post by **projectmx** » June 22nd, 2005, 1:44 am

it might be one of those things that some 96 models are and some aren't cause i believe some 93's have dohc engines

Devilhog · Post by **Devilhog** » June 22nd, 2005, 8:03 pm

Ya like they may have changed half way through production for that year or something. I know mine was made early on the 96 production run.

Yoda · Post by **Yoda** » June 23rd, 2005, 11:55 am

Technically OBDII only came into affect as of midnight Jan 1, 1996. It is possible that a what is called a '96 model doesn't have OBDII if it was built and imported before Dec 31, 1995 but more than likely if it does have OBDI it is really a car made at the tail end of the '95 model year. Most likely the mfgr date code for your car is of August to October '95. With the MX-3 this really doesn't make that much of a difference anyway. The 1.6 DOHC MX-3 was the test bed for Mazda's OBDII hardware starting at the end of the '93 model year. So '94 & '95 MX-3 are pretty much OBDII anyway even if they are officially not. The biggest problem with Mazda's early OBDII is that the ECU data mapping tends to pull any changes seen at the various sensors back to what it expects to see. This basically means that any or all gains associated with a performance mod is reversed by the ECU. This has being demonstrated in several published dyno tests back in '96 and '97. Even today the MS Protege has a similar problem where upgrades to the turbo do not increase the power as much as should be expected and after Mazda flashed the ECU with an upgraded software everyone with a modified MSP experinced a power loss.