Spray angle question...

[CumminsPower59]

A while back I bought some used injectors, ran them in my 92 for a bit, and pulled them when I sold it. They were laying around so I sent them to RC to have them honed and what not. Interestingly enough, I was informed that they have a 135 degree spray angle. My question is, can I run these 135 deg. injectors in my 91, which has the larger piston bowls? Is 20 degrees of difference between the injector spray angle and the shape of the piston bowl going to cause any ill effects?

[RCCUMMINS89]

I'll let a few others chime in before I answer.

[Tacoclaw]

Why, so you won't have to quote us later to prove you said it first?

My opinion, uneducated as it may be, is that you may lose some of your low end torque since you won't be using the entire bowl but it will allow you to advance the fuel timing about as much as you want to. Advanced timing helps out your off-idle response which is a good thing for DD-ing and general playing. If you're wanting to work it it may not be such a good idea as you be losing the efficiency of the larger bowl area and any timing advance would start hurting your spoolup.


Honestly, I doubt it'll make a lick of difference running-wise as long as you don't go too crazy with the timing.

[RCCUMMINS89]

Taco..........well said.

It'll make the truck less responsive. Possibly smokier upon take off............it will probably act as if you are not getting enough air.

Run thick washers found on the factory I/c trucks.

[CumminsPower59]

Well, I'm gonna have to run those 7mm to 9mm sleeves just to put these injectors in (which I got)...not sure how "thick" they are. I dunno, I was wanting to replace the 200k+ stock injectors, it seems to have a miss that's intermittent....

[RCCUMMINS89]

The adapters are pretty thick............I'd put them in and see how it runs.

Please keep us updated on the matter.

[CumminsPower59]

Sounds good. I hope to get them put in later this week, got to finish some other things on The Pile first...

[RCCUMMINS89]

To get a little more in depth on why I believe they will act the way they do.

The way Weston Shupe described it to me was.......A Marine angle injector (155 degree), the fuel has a longer distance to travel from the injector tip to the bowl and therefore has more time to "mix" with the air.

Now when I've ran 155 angled injectors (marine bowl or not) I noticed I had a more responsive throttle and could make the same and even more power per air in the cylinder.

Now anytime I've used thinner washers in my 145 angled applications.......I've found that just the opposite happens. Yet of course I'm then able to run more timing to clean up my idle smoke.......

So I would expect the same issue to happen yet again.

[CumminsPower59]

I installed those injectors today....not too bad down low, but there is nothing on the top end. They run hotter going down the road, about 100-200 degrees, and a little bit more smoke. I'm probably gonna buy something else to run, and sell these sticks, probably suit an IC truck better...

[RCCUMMINS89]

That's too bad. I would agree that they would suit an I/c truck better.

I wouldn't think they'd all that bad, but ............I've never ran an injector that that far off of a spray angle (narrower spray angle)


Where is your timing set at?

[CumminsPower59]

They aren't "that" bad, just less on the upper end than the stock injectors. On another note, first thing I noticed was that the idle dropped 300rpm...I had it set about 800, and its idling at 500 or so, they are bigger, but just won't work for me....time for some marine 370's???

[RCCUMMINS89]

Marine 370s are the best alternative IMO.........especially for the price.

Nyford is running a set. You could pm him and see how he likes them.

[CumminsPower59]

How much are they going for these days? Are they the 370 nozzles on 1st gen bodies?

[RCCUMMINS89]

Factory they are on 2nd gen bodies.

But a "marine 370" for a 1st gen, runs $425 + core

[ellis93]

Would there be a price on nozzle alone?