Big Injectors and Small Boost

[Xero]

Can you run a 550cc injector at 7psi? I know there's a limit to how little fuel an injector can inject, and when you get too big, you have to up the boost to make up for the rich mixture

pretty much, is anyone running 550s at 7psi?

[Nathan]

Hmmm, I wonder too because I was planning on running 7psi for the first 1000 miles until the engine is broken in. However, the 75# hr. injectors might not agree with that. I know my idle is going to suffer. I would think the 550's would be able to deal with it pretty well but I'm not sure.

[float_6969]

I hope so cuz thats whats going in my car and I'm not turning up the boost for the first 500 miles for sure. I should know after this weekend though, but I'm not sure if I'll get the injectors in time for the install this weekend. If I do, I'll let you all know.

[Trigger]

should run, but will be a little rich...nothing to worry about...just watch the gas gauge

[Nathan]

Well if we are all doing the same thing it HAS to work! Behold the power of positive thinking!

[Xero]

the thing is, I don't want it to run rich, si this that it'll run rich at stock settings (if adjusted through the computer) or will it run rich at the injectors lowest setting?

[Nismo1182]

Why does everyone "break in" their CA for a few hundred miles?

I see no need unless its completely rebuilt.

If not, the motor was "broken" in over 10 years ago.

The first day I started mine up, I made sure nothing leaked then proceded to put the smack down on a IS300 on my maiden voyage with the CA :ylsuper

[Trigger]

i agree nismo....i am planning on breaking mine in for about 2 miles....til i get to the gas station then time to play

Tim

[Nathan]

Oh...oops...I wandered into the CA section on accident I was talking about my soon to be freshly rebuilt KAT. Sorry for the confusion!

[float_6969]

Well, I have a brand new clutch that I have to take it easy on for the first 500 miles. (Stage 3 SPEC) So I guess I'm not really breaking the motor in so much.

[boost_boy]

Break-in? I hear everyone saying this fictitious 1000miles or whatever. If it's built right and the oil pressure is there, let that sucker idle for about half an hour and take it to da' house.

[CA19DET]

nah i think if it is a rebuilt motor the rings really got to seat/seal..... my engine builder breaks in his enignes on his warm up pass on the strip, 25psi flat out!!, ouch... but then again his motors only need to last a few races then are torn down and run up to 40psi in full race trim.....

[Nathan]

I dont remember where but I heard about two guys that both had motors rebuilt around the same time by the same shop with the same modifications. One of them beat on his motor for 1000 miles, the other babied it. The one that babied it came out with higher compression after 1000 miles, but the one that beat on it made more power on a side by side dyno between them. I'll probably just do whatever my machine shop recommends.

[float_6969]

There is a difference between a fresh rebuild and a used motor. With a rebuild, I'd DEFINATLY break it in. Regardless of what others think. With a used motor, it's totally different. You basically just need to "knock the cobwebs out" and your all set.

[Xero]

you are correct, float_6969, if you reabuild the engine, it needs break in time, end of story. The rings need time to expand and score the cylinder walls, this scoring will help the seal between the rings and the walls last, and in turn, help your engine last longer.

That magic "1000" was set by OEMs, every single OEM says no speed over 50 mph, and no revs over 3500 (or something like that) for the first 1000 miles. It is giving the engine time to settle in and all the imperfections in all the friction parts (rings to cylnder walls, bearings, etc.) to score and seat properly in their seperate sections.

A properly broken in engine will always last longer, and in turn run harder for longer, than one that was broken in hard.

[float_6969]

I couldn't agree more.