The Side Feed Injector Thread for a Gen 1 Viper by AndyMac

By diyauto
( 2 )

3 minute read

The Side Feed Injector Thread for a Gen 1 Viper

Compliments of AndyMac @

For a 1995 Dodge Viper RT/10

I'd like to get a thread together with information on side feed injectors, stock and larger replacements. Trying to avoid top feed injector swap info here, but if it is relevant, go for it.

So, the stock fuel system runs at 55psi. The fuel pressure is regulated in the tank, which means this setup has only 1 line from the tank to the motor. (the feed line)

Gen 1 stock injectors - 25lb/hr (black tops)
Gen 2 stock injectors - 29lb/hr (red tops)
Internal fuel rails in the intake are -8 AN (1/2")

A good side feed injector upgrade is the Subaru yellow top injector. They will flow close to 60 lb/hr at 55 psi. The down side is that they are really expensive new. Cost at the dealer is 150 per injector, which is 1500 for injectors plus tax. If you look on the Subaru forums, you can get 4 shipped for 150 - 200 bucks. This will require new injector connectors, and obviously some kind of engine management to compensate for the extra flow.

The Subaru injectors aren't a direct drop in, I believe that an O-ring swap from the original injectors would be enough. I'm also thinking that the tip may need to be filed down a bit to fit.

Here you see (left to right):
1) late model Nissan 300ZX TT injector. 370cc
2) Subaru yellow top injector 550cc
3) Stock Gen II injector 305cc
4) Nissan Maxima injector 240cc

These are all high impedance injectors, and all should fit without too much issue.

Soooo, why is the Maxima injector there you might ask? Well, I got 24 of them for 100 bucks. I wanted to try resizing the injectors to flow more and had some success thus far. I had some pics, but they are super fuzzy, so you'll have to imagine it.

The bottom of the injector has a plate micro welded to the injector with several small holes in it. This atomizes the fuel as well as limits the amount injected. If you remove the plate, the flow goes from 240cc to 550cc. Obviously the pattern isn't as good anymore, but it is similar to the stock Viper injector now. I rigged up a flow bench to test the flow rate before and after, and initial testing is good. I modded 20 of the 24 and plan to flow them all and see what the variance is between them.

I was thinking if there was a wide spread, I can use the individual cyl trim in the VEC to compensate for them.

I realize that this isn't for everyone, but I will give it a try and report back.

As a neat note, the TT 300zx injectors can be modded in the same way, but result in the same end flow rate. Nissan probably used the same base, just changed the restrictor plate and color. They are also really expensive too, so the Maxima injectors are the obvious choice for this test.