Thanks for your PM William, but I can't reply there until I have 15 posts.

Found the correct o-ring size:

Injector Dynamics 1000cc injector set for 90-05 Miata

Looks like we are not reading the dead time in the table correctly. The correct ID dead time:

http://www.injectordynamics.com/ID1000UF3B.gif or http://www.injectordynamics.com/ID1000SumData.gif on page Injector Dynamics - ID1000 Specifications

Seems to match their FNPW_OFFSET + MINPW. Better than Ford's numbers, but in the end, dead time is not a big deal if they do not differ.

I'll probably end up getting the GT500 injectors when I am finished tuning NA on my stock injectors.

Thanks for the idea and lead.

I got the FIC 775cc during their Black Friday sale. I like em a lot

Anybody try the new SP line of injectors from Fuel Injector Clinic yet?

They only list one size currently for the Miata, but I sent an email asking about other sizes.

They didnt have those when I bought mine. They look like a denso injector, assuming they're the new style denso this would be the first time I've heard of a big size existing. The new style Denso injectors are supposed to be better than the ev14s.

Though they are not promoting them, I heard they were available (as a special order) starting from 350cc, then in 50cc increments, up to 1050cc. They currently only stock the 1050's. Pricing is the same for all. ($530ish set)


I'm pretty sure they are a Bosch injector.

I just got a reply today and the answer was almost exactly what you said. Smaller sizes are special order from 350cc and up and the pricing was almost identical to the 1050cc although the guy said he would confirm pricing if I was interested. They actually recommended I just get the ev14 365cc considering the price is the same for all SP's and I dont need a large injector.

I am torn though between getting a set of ID 725cc and the FIC 365cc, and I am only considering the the ID725 due to ID matching low duty cycle tolerences so closely since this car is a street car and will have to pass emissions.

I think that small of an ev14 will still be leaps and bounds better than the stock injectors and easily pass smog, even if its not as closely matched as ID. So in your case I'd probably go with the cheaper alternative.

Your probably right on this especially considering it used to pass fine with old stock pintle injectors that i am sure are the originals.

I'm sort of in a similar situation. For my expected power levels, I certainly don't need all that much upside and besides I already have a brand new set of DW 335cc's sitting on the shelf, but I decided I'd still like a little more headroom, so I was actually juggling between the 525cc FIC's and the ID725's. If you'll note (Miata NA/NB ), the 525cc are actually cheaper than the 365cc model which is why I chose them.

One of the things I'm trying to determine is just how important the low duty cycle tolerance matching is with these smaller size injectors. I can see the immediate necessity with the bigger sizes because, well, they're huge, and as a percentage, their variations can really amount to something significant, but with something in the 525cc range and under, and in relevant terms, isn't there inherently more tolerance for a larger deviation such that we don't even need that level of accuracy? is it REALLY going to make tuning THAT much better? Or should I say, is it better enough to warrant a noticeable return on the extra $170 for the ID's? I know you get what you pay for, but I just don't want to pay for something I'll never really use, IF that is the case. :dunno:

The FIC900s idle just like stock.

I think it was Reverant that said 650 and under FIC's idled just like stock if not better, and everything larger was not as great.

I'm running ID1000's and the car idles flawlessly

He did, that's literally bought my FIC 650's and returned my Five Oh's.

In my hast this morning to get some injectors I made an offer on a set of ID 725's from seller awd_motorsports on ebay and they accepted it just a few minutes ago. $450 shipped for them so I at least saved $30 on them. Guess there is no going back now lol.

I also got an email response from Injector Dynamics regarding using the 725 for my application that I will share.

Andrew Campbell

Good Scottish name;)
Is there new de so injectors on the market yet that are comparable to the ev-14? That someone mentioned earlier?

At what point is a ID725 too big? I am aiming for the 150-155whp range with my new build.
Well, it should actually be a 175 range but I am detuning the top end for a flat power band because class is power/weight lmited.
excuse my ignorance and laziness to read this whole thread that is another language too me anyways.

what would the difference between running an rx7 injector or something VS id725's be?

ID and FIC are selling matched EV14 injectors, the EV14 represent a jump in injector technology. You should see better performance with those injectors over the RX7.

I installed a set of FIC 900's and the car idles perfectly. FIC also gives you a data sheet on your specific injectors to aid in tuning.

Would id725 be too much for a power target in the 150whp range?

Umm, I would guess around 3x too much. But if you're going aftermarket EMS and or planning turbo later on, then get them. They should run as well or if not better than stock injectors. But if you're not planning on turbo or aftermarket EMS, then stock injectors would work just fine.

Actually I see no reason to go bigger than stock if you never plan on going turbo. But that's just my opinion.

This handy page here has a formula you can use to determine what size injectors you need for a specific HP target: Fuel Injectors - Miata Turbo FAQ

In short, yes, 725cc injectors are overkill for 150WHP. I made ~250WHP on 550s. If you want headroom for more power later, then it's not a bad idea.