upgrade injectors

[16bit]

I have done a bit of a search to find what bigger injectors would be good for my 98 nb. I have only found what cc people are using more then what brand/model etc. Anyone got a clue where I could get some 450cc injectors that are a direct fit?

[Uncle Arthur]

Got to ask yourself what's the purpose of the bigger injectors, and do you have the programmable engine management to make them work, or the fuel demand in the engine so that you're A - not running pig rich, and B - actually requiring that much fuel.

You running boost? Have a look for injectors on www.miataturbo.net - there's a whole table linked from somewhere there that details model numbers for larger capacity injectors that will slot straight in.

I know Boags runs Supra (green top) injectors for fuelling his beasite - I'm running (tan top) 1.8's but we both have the engine management etc to pump in the increased fuelling that's needed to feed the engine with the turbo.

Work out what you need then look for the right injectors that fit, rather than the other way around.....

[Boags]

From memory:

Black top 7MGTE Supra injectors = 430cc

Blue Top RX7 Injectors = 440cc

(can't remember the colour - but fatty has them, PM him) Rx7 injectors = 460cc

Go to the DIY FAQ in miataturbo.net for a full list of direct replacement injectors. It's a sticky in the DIY turbo section.

Boags

[16bit]

thanks! I will have a fully programable comp and a supercharger. thanks!

[Boags]

Have a look for glen73's turbo build thread, he got some 550s I believe. Now THAT would leave you headroom for some POWAAAAAHHH.

[Sean]

Have a look for glen73's turbo build thread, he got some 550s I believe. Now THAT would leave you headroom for some POWAAAAAHHH.

DOnt get the RX7 550s, they have a crappy spray pattern and you may have trouble getting a nice idle from them.

If you're planning on upto 250hp at the wheels you wont need any more than a set of famila BP injectros, they can be had cleaned and checked usually for $150 a set, IIRC they are 380cc.

[CT]

www.powerflowinjection.com

[16bit]

cool 380 sounds enough. I am not going to be going for over 270whp as I don't really want to do the bottom end. It will probably make a max of 210 - 220 whp when dont.

[Juffa]

I have 330cc injectors, which is giving me plenty on fuel for my setup. I'm running 9 pounds of boost and haven't run lean yet.

J

[blackster]

01-05 Mazda Miata NA & TURBO 265cc - Thin Lt. Prple 95500-4060
Toyota 3SGE 295cc – Green Top
89-92 Toyota Supra 7MGE NA 305cc – Light Green Top #23250-70080
93-95 Toyota Supra 3.0L 312cc - Maroon Top #23250-46030
Toyota 3SGE 315cc – Pink Top
90-92 MX6/626/Probe Turbo 326cc - Gray Top #195500-2150
89-91 B2600 Truck 326cc - Gray Top #195500-2150
Mazda 323 GTX TURBO 360cc - Black Top #195500-2130
Celica/MR2 3SGE NA 370cc - Green Top #23250-74160
Mazda RX8 420cc - Yellow Body #195500-4450
Subaru WRX 425cc - Lt. Blue Body #3920
89-92 Toyota Supra 7MGE TURBO 430cc – Black Top
89-92 Mazda RX-7 NA 440cc - Blue Top #195500-5740
89-91 RX-7 NA 460cc - Red Top #195500-2010
Subaru STi 540cc - Thin Pink Body #3910
89-91 RX-7 TURBO 550cc - purple top


Complete list of drop in injectors for the NB, as mentioned above the RX7 550cc have a shitty single nozzle spray pattern making them harder to control idle.

FWIW on the SE you can run upto 330s without having to piggyack the ECU. If you do decide to purchase some second hand ones, you run the risk of a dud when you get them cleaned and flow tested. The price of new vrs second hand was not all that different when you factor in cleaning and flow testing.

As mentioned by CT, powerflowinjection.com is what i used.

[Boags]

I bought the fuel rail from the 7MGE (that's 6 injectors - 305cc) for $100 and got 4 of them cleaned. One was a dud and was flowing less than the others, so it was lucky I had spares.

Cleaning was $15 per injector including return postage from the cleaner (I found him through ausrotary.com and UA also had his cleaned by him at the same time).

Boags

[blackster]

I bought the fuel rail from the 7MGE (that's 6 injectors - 305cc) for $100 and got 4 of them cleaned. One was a dud and was flowing less than the others, so it was lucky I had spares.

Cleaning was $15 per injector including return postage from the cleaner (I found him through ausrotary.com and UA also had his cleaned by him at the same time).

Boags

305s will not give you much leeway if your looking to run 10psi or more. That is on the SE, and i gather SP/NB is running the same fuel pump.

I contacted MAZBIT from ausrotary the price of used rx7 injector that were clearned and test flowed was not really all that different from new. The price he quoted for cleaning was more then $15 if i dropped off some injectors.

If you strike it lucky you may be able to source some used used pink body STi 550s or Supra injectors 430s cheaply from US ebay, i didnt have much luck after scouting for a month.

If you go for 550s irrelevant if they are RX7 injectors with a piggyback you will have a hard time with the tune.