I live in central Ny, Right on the lake. It has snowed many feet here, and the temperatures have been as far down as -14F. I have driven my car in teh bad weather a little, and I have started it 3 or 4 times in the cold. So far, something strange has happened twice. Since the weather is very strange here, things tend to melt and freeze alot. Anyways, the other day and today, I started my car, and it sounded like glass shattering (kind of) liek there was ice all over the engine. I allowed to let my car heat up for 10 mins. My question is, is this really abd for the car? Will I see a loss in performance? I plan on dyno'ing my car this spring to see what kind of hp and tq ratings i've getting. Another question: I heard differnt kids of dynos read differently (like dynopac and dynojet?) Which dyno is the most accurate? Which dyno reads the lowest ?

 

dynos read different, but a dyno is really only good for comparisons on your own car, different dynos are calibrate differently. and by getting a high reading dyno, you only get bragging rights online, it makes no difference to your car. just like people talk about doing it in 3rd 4th or 5th, the .2hp difference makes no difference if your consistant in the gear you use.

with that said, Ill answer your question, the highest dynos are the ones that bolt directly to your hubs, without wheels, thats approx 40lbs of rotational weight that wont suck power like it would on a drum based dyno. does that mean you have more power than the next guy? nah, just that your reading hp without wheels, so technically your lieing when you would say you have X hp at the wheels, you have X hp at the hub, not the wheels.

and for the cold, 10minutes may be hurting, probably not tho. your best bet is to warm it for about 2minutes, that will get the oil circulating, beyond that, start driving REAL SLOW, under 2000 or 2500RPMs, no hard acceleration. you cold idle at 1500, so when accel no higher than 2000 your not doing much except heating the engine faster, but not overheating or anything, and your engine wont have to run in "cold mode" as long. stay real low till the needle starts to perk up, then drive like a normal person, after about 5 or 10 minutes of the needle being at normal temp, you can begin to drive like a normal person that drives a Z . but be careful, the tires might still be a bit chilly, and traction sucks.

 

The hardest part on the engine is the cold start. What oil are you running? I run Mobil 1 5w-30 and it stays fairly thin even when it gets this cold. As soon as the oil pressure builds, the engine will be fine. If you are really worried about cold weather damage you could buy a block heater or a pre-luber to build oil pressure before you start the car.

 

As I posted in the Technical problems forum...

Warming up your car for more than 1 minute does more harm than good.

The fuel mixture on startup is super-rich... a lot condenses out on the cold cylinder walls, and the mixture would not fire if it were other wise. The condensed fuel drains past the rings into the crankcase, diluting the oil and, if it stays there, eventually breaking down to form an acid.

The longer you 'warm up' sitting idle, the longer the walls remain cold, up to about a minute. If you drive off as soon after 30 seconds or so, the engine will heat up faster, re-evaporating most of the fuel in a half hour or so of driving. Since cold engine tolerances are not conducive to aggressive driving, just drive mellow until the temp gauge rises to normal.

The worst combination, though is a long warm-up followed by a brief drive. If you drive will be 20 mi. on the freeway, then the only downside to a long warmup is wasted gas and a lot of exhaust sitting around your house. There is no benefit.

So, the best solution is to let the car warm up for about 30 seconds, then drive it easy, keep it below 3000rpm or so until the motor is up to temperature.

 

Its -25 deg. outside. My z is housed in an unheated garage. I don't let the car warmed up before driving. Soon as the car started, I start driving. As long as you don't abuse the car in the initial 5 min. of driving. I don't think warm up is needed.

For the driver, it is nicer to have a warmed up car. I don't think the car needs it though.

 

I'm a very real world person. I hate taking credit, or making claims that could even possibly be wrong or exaggerated. I don't like to give something empty meaning, whether it's a car or something else mroe important. If I had 3 different dynos, I would report the mothods used, and I would claim the lowest result. Btw, So where does a dynojet hook up to?

I don't know what kind of oil I run, my Z isn't even past break-in :P

Awesome. THat is how I have always treated my cars. My father likes me to heat it up longer (he's pigheaded sometimes)

OK, you bragging? jk Yeah I wish I had a garage to protect my Z

 

Im not familiar with models, and but I think the dynojet hooks to the hubs. and you might say the whole thing, but there have been those that dynoed on the hub type, and right after everyones talking about how the Z dynos 250 to the wheels.

regaurdless, do the dyno for yourself, if it comes out lower than you expected, dont worry about it, it probably was due to conditions and/or calibration. your car is the same as everyone elses basicly.

 

All the DynoJet dynos I've ever seen / used you drive on.

 

Dynojet makes a variety of types but the ones I have seen in speed shops use rollers driven by the tires. We used to have a dynojet water brake engine dyno (driven off the crankshaft) when I worked at United Technologies Diesel Systems. It sucked as far as accuracy but was OK for the endurance testing we did on it. The best (most accurate & repeatable) are electric dynos, either DC or eddy current. These are the types used by the engine manufactures for their developement work where it is important to control all the variables and be able to compare the test you run today to the test you ran last year or next year.

I have to laugh when people run their car on a chassis dyno (the type driven by the rear wheels) and try to claim that their mods made a 1 or 2 horsepower difference. These tests are not repeatable within better than 1% at best. I'm not knocking doing the testing, it's a lot better than seat of the pants, just realize that there are a lot of uncontrolled variables.

 

I am doing it for myself. But, I'm just wondering how my 350Z stacks up...because it seems there is alot of variability in the hp/tq numbers. However, I am doing it for a before and after comparison with mods. If I add a CAI, i'm not going to dyno it. I woudl wait till I got exhaust/CIA/etc, etc. How hard would it be to find an electric dyno? You guys still havn't made any suggestions on which one I should use.