cantrade

Hi,
Newbie here and driving a 1996 Miata N/A. Although nonturbo I thought this would be an excellent place to ask some questions about Megasquirt conversions. This car is used only for auto-x and track days.

Goal: Raise and broaden the torque and hp curves by about 7-10%. I am considering doing this with a MSPNP.

1. If I use a wideband O2 sensor what happens to the two O2 sensors now installed? I have one above the cat and one below. Does the wideband simply replace one and the leads in the original harness are ignored by the PNP?

2. Where do the wideband leads plug into the PNP.

3. I will also replace the MAF with an IAT sensor from GM. This looks pretty straight forward.

4. I saw a reference to building a kit which will make the cost about 1/2. I like the idea of having the original harness in tact incase I decide to reinstall the original ECU and wonder is that is possible If I go the kit route. Also, I wonder about the real, finished cost of doing it with a kit vs. the DIY PNP way.

5. Lastly, is this the best way to achieve my goal or would a rechipping do the same thing cheaper?

Thanks for any advice you may have.

Don

kotomile

iTrader: (24)

5 - Being able to delete the MAF and control your A/F and timing will be worth a few ponies, not as many as if you had FI. Might not be worth it from a cost/benefit standpoint. This would place you firmly in CSP if you aren't there already, right?

cantrade

Right, I would be in the very competitive CSP class since I am running with SCCA. Might not be worth the almost $1,000 price tag including the WB O2 sensor.

Don

dynokiller90

cost/beni aside if you are the constant tinkerer type it's worth it for the hours of fiddling, futzing and knowledge you'll gain about what exactly is going on at a given moment. All out hp #s I don't think is where you'll see the gains. tip in and part throttle will make a pretty good difference though. you can just be that much more precise with your adjusments, because it's for your car and not a generic tune.

cantrade

dynokiller90,

I must admit that is a big part of thinking about getting the Megasquirt. I have some mechanical knowledge but mostly with carbs and early Bosch EFI units when I owned a German car repair in the 1970s. The newer microprocessor controlled engine units are pretty much a mystery at this point. (The reading I have done has not been totally foreign and I recognize the terms, etc.)

At this point I know that I cannot see how the generic chip burner shops can provide a chip that fits all since there is so much variation between individual cars and their equipment. DIY will not even try to provide a hop-up map for that reason. For that reason, the MSPNP makes a lot of sense to me. Cost/benefit is not quite there though.

Thanks for the input.

Don

boileralum

iTrader: (8)

You might consider having mt.net member Braineack build a MS for you. He has several options available, from standalone to parallel install, and is cheaper than the MSPNP unit.

cantrade

That's a thought. i will look over the options he offers.

Don

hustler

iTrader: (6)

my 1.6 was noticably faster on the butt dyno, and went from 25-32mpg. The biggest advantage was getting rid of the "sad spot" from MAF restriction. If you ever plan on going FI, this is a good mod from the start.

cantrade

I have a definite hesitation when accelerating from dead stop. It seems like the EFI system takes a while to get on step, so-to-speak. If it had a turbo I would blame it on spool up time but it does not so it has to be a built-in lag in the stock system. It is not bad if I simply ease on the throttle but if I floor is there is a lag.

Also, if I drop down too low in second gear to say 2,500 rpm it takes forever for the engine to get back up to the power curve where it is happy. This engine seems to really like 4,000 to 6,000 rpm. So, I try to keep it there but the courses are all different and at times it is not worth down shifting for a second or two so I end up on the rev limiter instead. Of course, the power is going down at that time.

I am thinking that getting rid of the MAF would be a good thing.

Don

hustler

iTrader: (6)

With a road tuned VE table and the standard DIY spark table, all this **** was remedied immediately. Judging from driving my other 1994 miata, intake piping and exhaust will fix this too.

cantrade

Hustler,

Thanks for your opinions and observations.

Which MS are you using and do you have the WB O2 installed?

I think half of the fun would be on the dyno and road testing the system!!

Don

hustler

iTrader: (6)

I have the diyautotune version with an lc-1. T

I guess tuning it is fun. I'd rather have seat time at the track, chase women, sleep, or blow fish-scale off a hooker's *** than work on cars...but yeah, I guess its fun to learn about EFI too.

dynokiller90

so here's a question for ya. . . what all do you have done to your car now? if you have a big exhaust, header and all the usual b.s. then you'll be able to take full advantage of those parts rather than just bolting them on and hoping that the fueling is somewhat close. I would imagine that if, say you put a header on the car and gained some power up top but dropped a bit in the mid range that you would be not only able to gain back the loss, but maybe even gain a bit more all around. I wouldn't think about it so much in terms of hp per dollar cost. I would think of it more as potential for hp and a better return hp per dollar wise on the other upgrades that you do.

cantrade

I haven't done a heck of a lot to the engine. I have been running in a stock class and am pretty restricted.
I run timing at 14 deg.
I am currently installing a Jackson Racing cat back exhaust.
The a/c is history.
P/S is history also.
Koni Sport shocks.
Auto-x tires.
No intake modifications are allowed in stock.

If I change class I will do the ECU, springs, and a intake system. (Probably am out of spec for my class now since I have done the above.)

I have not thought of an exhaust header but should consider that.

Don

cantrade

Bottom line is that I do not expect too much from the engine. 10% would be great.

D.G.