4 cyl SOHC Questions - Efficiency Problem and Possible Turbo

[denisizzle]

Hey guys I've got a few things I'm curious about, here's little info on the car: It's a 1993 4 cyl SOHC, right now it has a cold air intake and a throttle body spacer. So my questions are:

1) I'm only getting 405 km/ 37 L of fuel, this seems pretty bad. I just did an oil change and I had an inspection done a couple of weeks ago that said I have a leaking valve cover gasket but I've never had any problems so haven't bothered to do anything about it. Is that a big problem?

2) I'm considering getting a turbo installed, is this difficult? How much horsepower would it add?

Thanks for any help

[Daninski]

Valve cover gasket is a pretty easy job, it may be leaking into your spark plug wells.
Turbo, sure if you have the money and your SOHC isn't already tired. Most people opt for a BP swap.

[denisizzle]

So the gasket would definitely reduce efficiency or no? Because I hear of people who get 700 kms of a tank and I'm getting about 450.. I guess for now I'll replace it and the spark plugs and see how that works.

[burgess]

A valve cover gasket isnt going to give you another 250 kms to the tank. I'd suggest change wires,plugs, distributer cap and rotor button. If you dont want to spend a lot of money buy a newer air filter for the stock box or get a cold air intake. Check if stock (assuming stock) intake hoses have cracks. Make sure your not running low air in your tires which will affect your gas consumption quite a bit. Use some fuel injector treatment and run a tank of higher octane gas.

[Ryan]

I found the SOHC to not be that great on gas. The most I ever got on mine was 600 from topped up to well into the fuel light. My BP was comparable (450 -500) but 40x more fun to drive, the K8 was a little worse (400-450) and my KL is 450 on 100% highway, more likely 380-400.

Wow, just noticed I've owned 3/4 of the engine options for MX's....

Anyhow, like burgess suggested, do the routine maintenance that has likely been avoided, and do a proper tune up.

The thing is though, by the time you spend all the money on these parts, the amount you might save in fuel won't pay for itself for like 4 years.

I suggest doing a compression test to get an idea of how healthy the motor is before you dump too much money into stuff that isn't really broken. If you have poor compression, no amount of bolt on replacement parts will help you.


Turbo-ing the SOHC is a chore, as there are pretty much exactly 0 aftermarket options. No header, no pipes, no piping whatsoever, and plus now you need engine management (unless you're hack like that), the list goes on and on... the cheapest setup will still likely run you 2000+.

[denisizzle]

Wow thanks for the heads up wasn't expecting it to be that much. The only reason I would like to keep this car is because I have so much other stuff in it like subs, body kit, aftermarket speakers and deck and so on. I suppose I will do the easy replacements like gasket, distributor and spark plugs. How do I go about checking the compression ratios? If these turn out good then the engine if properly maintained should be reliable and last for awhile?

[Ryan]

Its a fairly inexpensive tool. Perhaps an autoparts store would even lend you one, I've heard of some American chains that do that.


It looks like this:



And screws into the spark plug hole.

Here's how to properly use it.

http://www.mx-3.com/phpBB3/viewtopic.php?f=15&t=78061

[Nd4SpdSe]

Turbo-ing the SOHC is a chore, as there are pretty much exactly 0 aftermarket options. No header, no pipes, no piping whatsoever, and plus now you need engine management (unless you're hack like that), the list goes on and on... the cheapest setup will still likely run you 2000+.

It's a bit of an old post, found it while searching, but figured to point out that there is one, single, option:
http://racingmazda.com/mx3_turbokits.htm
If they still make it, but seems they're still around.....

[RS_OBD'oh_2]

Turbo-ing the SOHC is a chore, as there are pretty much exactly 0 aftermarket options. No header, no pipes, no piping whatsoever, and plus now you need engine management (unless you're hack like that), the list goes on and on... the cheapest setup will still likely run you 2000+.

It's a bit of an old post, found it while searching, but figured to point out that there is one, single, option:
http://racingmazda.com/mx3_turbokits.htm
If they still make it, but seems they're still around.....

A couple times a year someone post that link. When lime was more active on here... He said he knew the owner. Long stroy short, as per Lime, several years ago... they stopped making that kit. probably close to 3-4 years back now.