So lost :-(
 

Well as my first post, i'll make it one that counts...I've been reading these forums for awhile now, and i'm offically stumped. Here is my set up, and my problem.


Built motor .20 over
Ported Polished Head (All the goodies ti retainers/springs/etc.)
T61 Garrett Turbo .48 hotside
3 inch DP
2.5 IC piping
All other supporting mods'
Planning on running 20+ PSI

The Problem

I'm very close to buying the MegaSquirt but I have no idea where to start. I don't see many people boosting as much as i'm going too. Will the MegaSquirt support 750CC Injectors? I saw that they supported up to 550CC
but has anyone ran bigger than that? Just very confused on where I start with all that? Sorry for all the newbe questions but im very close to completion of this project and running out of time...Thanks for all the imput guys.

Yes MS will control 750cc injectors. People run over 1000cc injectors with MS, it's just not common on miatas cause not many run that much boost because we like to save money on transmissions and rearends.
What year is your car.

Fill out your signature with that same info so others will know in th future. Welcome to miataturbo.net

Thanks for the imput, It's a 90' is there anywhere that I can get a good base map?

diyautotune.com is the premier developer and retailer for MS for the miata community. We support them pretty well here because they have developed the MS PNP for the miata from 90-95 already in the past year. You can of course do a DIY setup but the PNP is very nice.
They also happen to support the forum and have a banner at the top of the page. Base maps have been developed by them for immediate startup with their MS PNP and they share their base maps freely. Though they are not scaled for 20 psi, they could be adjusted though the timing map would be off a ways i believe. Running 20psi is no joking manner, expect substantial load bearing dyno time.

MS will control whatever sized injectors you fit (where did you hear of a 500cc limitation?)..... however, I run 600cc High Impedance injectors, and *just* manage to get a stable idle. 750's are going to give you a really *really* small idle PW. I.e. you're idle is going to be rubbish.

MS can control low impedance injectors too, but IIRC the circuit doesn't work properly with the MX5 mods, so 'as is' it probably won't work. (happy to be proved wrong on this point though!)

*however* it is possible to buy injector driver boards which will allow you to use low Impedance injectors properly (i.e. not using resistor packs and effectively turning them into High Imp). The guy that makes/sells these injector driver boards posts a lot on www.msextra.com so shoot him a PM for more info. The advantage of going via this route is it'll allow the finer control that low Imp injectors offer AND you can run the Highres code*

Also please d/load and read the Megamanual, it'll answer all sorts of questions like this.

*The highres code forefits low Impedance injector PWM control for a finer resolution i.e. your PW's look like this 2.345 rather than this 2.3

Is there a link for the megamanal?

ever heard of google? seriously it's the first frigging hit...

http://www.google.co.uk/search?sourc...e+Search&meta=

Though we don't offer the MSPNP with the hi-res code out of the box, there's no reason you couldn't load it up and idle big injectors all day long. If your 750's are low-impedance you could use a resistor pack and treat them like hi-z injectors with no major impact.

I suspect the limitation people have seen running low-z injectors on the Miata is a ground limitation, as the stock ECU grounds are adequate at best, and thats for the stock hi-z injectors. Low-z injectors sink ALOT more current and would need significant additional grounding outside of the stock harness wiring. Then I doubt it would be an issue. This would of course be when running the standard MS1 Extra (non hi-res) code.

The link to the MegaManual is actually www.megamanual.com and manuals for the MS1 Extra code that most Miata guys are running, including the MSPNP, is http://www.msextra.com/manuals/MS_Ex...nual_Index.htm.

No i went through to link you posted... :asshole:

Thanks Jerry

Interesting thoughts Jerry, how would you propose to run additional grounds? direct from the injectors to the block, or parrallel to a central point on the chassis? I wouldn't mind 'upgrading' to Low Impedance injectors in the future.

I find it quite scary that a Mod on a forum dedicated to building a DIY ECU doesn't know how to search, and who's first response to being told how to search is to throw insults about. :td:

Running additional grounds from the MS ECU to the same ground point on the block. Best solution would be two to four 18-20ga wires, each from a separate ground pin on the MS, run individually back to the same point on the block that the rest of the ECU grounds go back to.

cool, I'll add that job to the list then!

Thanks Jerry

who gives a fuck what you find scary or not.

I looked in the link you posted and it wasnt there. WHy the fuck would i search from something, I assumed you were competant to post a link. I was wrong. It wont happen again.

And as for my response you were rude i responded in like

my what a pleasant chap you are.

good day

EDIT: seeing as you've edited ;)

Are you saying the link i posted to a google search didn't show as the 1st hit a link to www.megamanual.com?? I think you should look again....

Apologies for sounding rude, but it would've been much quicker to actually search for the megamanual yourself than actually being babysat to it.

There is also a big difference to being rude - which granted I was, and being insulting which you were.

Well im not here to split hairs. Ready dear abbey and discuss the article with your lifemate steve is thats your idea of a good time.

You are an idiot. Your first link did not show megamanual. Yes after i asked for a link you, you responded in a rude fashion with a google search.

you're the idiot, the link i posted was quite blatantly a link to google, the URL was plain to see, the fact that being able to press a mouse button twice eludes you does not surprise me in the slightest.

you can lead a horse to water.....

anyway I'm bored now have fun reading the Megamanual :)

God damn, where in that post is a link to a mega manual?

Oh yeah thats what I thought. ITs NOT

The effort you have taken to ask for the link... is more than it takes to just goto www.megasquirt.info or www.msextra.com or www.msefi.com.... all sites you'd pull up with a simple google search.

Nope never was, it is however very easily found from the next post by me after you requested a link.

If I'd edited the post after you'd requested a link you'd still be pissing and moaning as you wouldn't have noticed it had been modified.