5th injector
 

I have not seen many references to 5th injectors here.

I currently use http://www.witchhunter.com/flowdatapix/d2325022030.jpg Corolla T Sport injectors at 99 stock fuel pressure.

These are good up to 10 psi boost but not much more....... so I added a 5th injector.:noob:

https://www.miataturbo.net/attachmen...ine=1335898752
https://www.miataturbo.net/attachmen...ine=1335898752

(I plan to control this with a EMB autotune aux injection TPS map but with a slight offset to the main additional injection autotune map.)

Why?
I run with low 7 psi most of the time as dd / stock brakes / police.
The 320 pintle injectors I have now are probably more economical than say rx7 injectors and gas in Slovakia is 7.4$ a gallon for 95 octane. :facepalm:
I don't want to spent $$$ on proper injectors that will get maxed only now and then when its possible to get the same result with a 5th injector.

Is there some thing inherently bad with using them?
Any suggestions would be appreciated

First off, $7.4 a gallon is too damn hi. Sorry bout that for ya.

Is the injector in the best place? I thought they needed to be closer to the TB to keep the fuel atomized better. People in the MKIII Supra world use to go with a 7th injector years ago. Some would go as far as using a different fuel for the extra one or two. Hope it works out for you.

Sounds like the OP's country needs a "The gas is too damn high" party in their political system!

Or just save up and move to the usa

The only real inherent problem with the 5th injector setup is the chance for uneven distribution of fuel - if one cylinder runs leaner than the rest, your total AFR might be safe, but the lean cylinder might be in a danger area.

While I understand your concern with getting injectors that will only be maxxed out occasionally, supersize injectors which will never see 60-70% are starting to become trendy with the availability of the EV14 units. A 1000cc EV14 unit will atomize so much better than stock that you'll likely see not only better idle, but also better fuel economy - and you'll probably never touch 1000cc.

Good information here fooger03. I have started to look for EV14s!

Thanks Miater for the heads up. I can move it about 10 inches closer to the TB. (Just before the silicone 90 coupler). I kept it low close to the frame to keep the fuel hose short but as you point out many people fit them right next to the TB.

Gotta +1 on Foogy's suggestion for EV14's. Very happy with mine - and I'm having to remove fuel all over my map with them.

Will you sponsor me?

My previous employer said that I was capable of limited tasks under close supervision;)

I used to drive with 5th injector and piggybacks. Back then I paid $9.2/gal for 98RON fuel

Now I’m running four big injectors with standalone ecu and pay $4.8/gal for E85 bioethanol

moral of the story is, forget 5th injectors and piggybacks :td:

Nice car spec muoto! I hope I will get to something like that eventually, stand alone, rods, ability to run fancy fuel. (I have never seen bioethanol for sale where I live but I guess it will come.)

tr00f.org

ew this is disgusting

thanks for the tip Faeflora, I think I am on the right path now!

What size are these I wonder? (Sets of 10 have sold for under 100$.)
http://stores.ebay.com/Reliable-Tool...=1580591&_sc=1

I love how they don't tell you the flow rating...

My guess would be in the 20-30# range.

I have 350cc, 450cc, and 700cc sizes for $339 in a FLOW-MATCHED set of 4.

Fuel delivery is one place you don't want to skimp on your build. Having an injector that far up the stream, your delivery to the injectors will be similar to the air delivery. A lot will go to 4, average will go to 3 and 2, and the least will go to 1.

After looking some more I guess they are 500 cc (47#) ford injectors.
https://www.miataturbo.net/attachmen...ine=1339699023
The part number if you look closely is 0 280 158 193 and they have a brown (not orange) ring like the ones here http://www.ebay.com/itm/Standard-Mot...-/150734776805

They are not a great match for MX5/miata even though they are the correct length.:facepalm:
The electrical connectors would have to be made to fit by cutting material off the tabs but the real issue is that the fuel rail would have to be modified as the injector inlet diameter is bigger than on densos.

https://www.miataturbo.net/attachmen...ine=1340138869
It will fit without modifying the fuel rail!
Just need to remove plastic body material with a lathe where the top O ring sits.
Brand new500 cc EV14s for 5$ each:rofl:

Nice dude, that's the kind of stuff I love seeing!

https://www.miataturbo.net/attachmen...ine=1340197758

reduced shank diameter to 10.7 mm, added clip washer and O rings.
(Single O ring would probably do but when there is space, why not 2?)