Hey so my car (05 6mt coupe) has only 75k miles, but I am thinking about the longevity of it, and the fact that one day I want to go FI. Is it worth it to rebuild the engine with forged internals before anything significant even goes wrong? I don't know much about it, but I thought it might cost less to do now vs later. Thoughts? In addition, maybe I could have it done during the winter months anyways so I'm not tempted to drive it :P

Phil

 

75k is barely broke in for these motors. You got another 100k easy on that motor if well taken care of.
but if you plan to go FI anyways, might as well build it up at the same time as the FI install.

 

Got 153k miles on my VQ35, modded and tuned. Knocking down nearly 27 mpg on trips with an average speed of 75 mph (speed limits are 75 and 80) with about a quart of oil every 6000 miles. That's double your mileage and the motor still seems really healthy.

 

OK. At what point should a new engine be used for FI? If the original has over 150k? Or is it irrelevant if I build it with forged components etc?

 

Honestly, with just 75k, assuming the engine was properly maintained and isn't an oil burner, you should be fine if you don't go too nuts on the boost or nitrous.

 

I wouldn't do it if it were mine... I'd rebuild (or buy a built motor) and go FI on a zero mile engine. Biggest reason is the life expectancy is SUBSTANTIALLY lower with forced induction so you might get 50-75k out of the motor before it's fried, if you rebuild now then you'll get 125k before rebuild.

Also there are a TON of variables that you don't know about that motor, how abused was is in the past? Trying to judge the extent of "normal" wear and tear can be impossible for some components like bearings. At very least do a compression test on the motor to see how much life is left in the rings.

It also greatly depends on how much you actually plan on driving the vehicle AND how hard you will be on the engine.

EDIT: Rule of thumb for FI, no go if over 60k already on the motor.

 

Okay good to know about the 60k. I don't know much about how the previous owner treated the car, but I've treated the motor well since It has been in my care.