Looking for the truth on a buncha different topics...

[grndslm]

Sorry for not separating these into different threads... didn't think it was worth it.

I'd also prefer answers only from people who really know what they're talking about... not guesses, theories, etc. I want the truth from experts and nothing less.

(1) Why can't I change from synthetic back to regular oil? What would happen if I did?

(2) If I did run synthetic, but was leaking oil from the valve seals (a quart every 1500 miles or so)... could it possibly be more beneficial to run SAE30 (straight 30 weight) as opposed to synethic??

(3) What's better for an automobile, cold or warm air? For the first time ever, I read someone on this board mention warm air is better... stating that cars run better in the summer than in the winter. What's the truth?

(4) Does acetone really help that much? I'm going to try myself next fill up, but wondering if it's really just to remove gunk or best for carbueraters or what?

(5) Also, what's the truth about drilled & slotted rotors? Good or bad? People like to say that because you take away some surface area away from the brakes, you actually decrease braking ability.. but I remember from physics that friction doesn't depend on surface area in any way.

(6) Will driving with my hood off make my car *that* much less aerodynamic? As long as I stay off the interstate, I doubt my MPGs will see that much of a hit. If anything, I'd expect it to increase since that hood's definitely not light.

(7) If my fuel pressure regulator is messed up, what's the disadvantage of *slightly* unscrewing my fuel cap? My real problem is that when I leave the cap all the way on, and I fill up, then sometimes fuel shoots outta the tank and soaks some electrical wiring around the fuel pump area.

(8) How can I force my radiator fan to come on without wiring it directly to the battery and turning on the A/C? I don't ever seem to notice that the fan is on while driving... but it does turn on when I turn the A/C on. Is this normal?

[KiwiBacon]

Originally Posted by grndslm

(3) What's better for an automobile, cold or warm air? For the first time ever, I read someone on this board mention warm air is better... stating that cars run better in the summer than in the winter. What's the truth?

Warm air reduces pumping losses which has a fuel economy benefit. It also reduces engine power.

Originally Posted by grndslm

(5) Also, what's the truth about drilled & slotted rotors? Good or bad? People like to say that because you take away some surface area away from the brakes, you actually decrease braking ability.. but I remember from physics that friction doesn't depend on surface area in any way.

Surface area is a factor, but not a big one. The biggest concern with drilled and slotted rotors is cracking.

Originally Posted by grndslm

(6) Will driving with my hood off make my car *that* much less aerodynamic?

Yes. It will hurt fuel economy.

Originally Posted by grndslm

(8) How can I force my radiator fan to come on without wiring it directly to the battery and turning on the A/C? I don't ever seem to notice that the fan is on while driving... but it does turn on when I turn the A/C on. Is this normal?

The radiator fan only turns on when the engine needs it. Otherwise it's just wasting power.
The fans come on with AC because the AC radiator needs to stay cooler than the radiator does.
Perfectly normal.

[MagicRat]

Answers in no particular order.....

Acetone is useless as a fuel additive.

Unscrew your gas cap very slowly!! A loose gas cap affects emissions control devices, is dangerous (fuel/vapour spillage, esp in a crash, loss of cap, etc) and may produce a 'check engine' trouble code in some cars, especially later OBD II electronics. Leave the cap tight as intended. Oh, and fix your regulator, so your car will not run too rich and waste fuel.

You can change back from synthetic to natural base oil.

Fix the valve seals. Running straight 30 oil is a band aid when the oil is cold and will have a minimal effect when the oil is hot. 30 weight WILL increase engine wear upon initial start up because it is thicker when cold and does not flow as well as multi grade oils.

Your fan has a thermal switch and only comes on when it has to. If your car is not boiling over or really overheating, then do not worry about it. The car will get slightly better mileage with the fan off anyways. You can wire up a toggle switch (mounted on the dash) to bypass the thermal switch.

Warm air makes for easier starting and less engine wear when the engine is cold................Cold air makes the engine produce slightly more power, because the air is more dense and has more oxygen per volume.

Leave the hood on the car. No hood increases drag on the highway and will get you unwanted police attention and possibly a ticket for equipment violations.

Drilled rotors benefit cooling under some circumstances and make the rotors slightly lighter(less rotational mass= slightly faster acceleration.), but reduce the rotor mass and their ability to soak up heat, which can lead to brake fade and warpage. . It's best to leave the rotors as the factory intended unless you must go to the race track.

[Moppie]

Some interesting questions, it always amazes me how much mis-information there is about cars.
Most of it in total contrast to come common sense.

Answers in red:

Originally Posted by grndslm

Sorry for not separating these into different threads... didn't think it was worth it.

I'd also prefer answers only from people who really know what they're talking about... not guesses, theories, etc. I want the truth from experts and nothing less.

(1) Why can't I change from synthetic back to regular oil? What would happen if I did?

You can change. No harm will come. Just don't mix the two types, as sometimes they will mix well, and sometimes they won't. As long as you completely drain the sump of one, before filling with the other, then no problems.

(2) If I did run synthetic, but was leaking oil from the valve seals (a quart every 1500 miles or so)... could it possibly be more beneficial to run SAE30 (straight 30 weight) as opposed to synethic??

Running a thicker oil may reduce how much oil you burn, but it could have negative effects else where. There is only one way to properly stop the engine burning oil, and thats to rebuild the head.

(3) What's better for an automobile, cold or warm air? For the first time ever, I read someone on this board mention warm air is better... stating that cars run better in the summer than in the winter. What's the truth?

The cured pork answered it very well. But to add to it, hot air mixes better with the fuel from the carb/injectors. Its why most carb set ups are warmed with hot water from the engine. Cold air is more dense, so you can fit more of it in the engine, which when combined with more fuel, can give you more power.

(4) Does acetone really help that much? I'm going to try myself next fill up, but wondering if it's really just to remove gunk or best for carbueraters or what?

There is a thread on this very subject somewhere. Acetone in your fuel will do nothing to improve your millage. It might clean gum out of the fuel system, and at the same time it might perish rubber parts causing leaks.

(5) Also, what's the truth about drilled & slotted rotors? Good or bad? People like to say that because you take away some surface area away from the brakes, you actually decrease braking ability.. but I remember from physics that friction doesn't depend on surface area in any way.

Heres a complex topic, and one that there are many threads dedicated to.
You need to things to make a brake disc work. Surface area for the pads to work on, and some way of removing the heat.
Now note that there are two different types of slots in a rotor:

• a: The ones between the pad surfaces found on most modern disc brakes. If you look at the edge of the disc they appear as holes around the edge. These are slots that move from the inside to the outside edge, and provide extra surface area for cooling the disc.
• b: Slots on the surface of the rotor. These are supposed to allow the hot gases coming of the pad to escape.

Holes drilled in a disc are supposed to the same thing. They are also supposed to help cool the disc by increasing surface area.

There is no evidence to suggest that the second type of slotted disc is better than drilled, or vice versa. In fact there is very will evidence that they have positive effect at all. Especially since modern high performance brake pads generate very little gas during braking.

The only know down side to cross drilling a disc is premature failure. Cross drilling a cast disc, that was never meant to be drilled, can weaken it, and a disc brake snapping in a half under brakes is a good to have a really bad accident. You can of course buy cross drilled brake discs that have either had the holes cast into them, or cast with the intention of drilling.


(6) Will driving with my hood off make my car *that* much less aerodynamic? As long as I stay off the interstate, I doubt my MPGs will see that much of a hit. If anything, I'd expect it to increase since that hood's definitely not light.

Why would you want to? Nothing good could from it, except rain water in places its not meant to go......


(7) If my fuel pressure regulator is messed up, what's the disadvantage of *slightly* unscrewing my fuel cap? My real problem is that when I leave the cap all the way on, and I fill up, then sometimes fuel shoots outta the tank and soaks some electrical wiring around the fuel pump area.

Think about this, how is unscrewing your fuel cap going to help? The cap is vented anyway, as the fuel tank is not kept under any pressure. The system is only pressurised between the pump and the carb/injectors. Sounds like you need a new FPR.

There are also two problems here, where is the fuel shooting out of the tank? Sounds like you might also need a new fuel cap, or there is something wrong with a seal, joiner or fuel line somewhere.
Of course if your filling up with the cap on, it could cause some problems

(8) How can I force my radiator fan to come on without wiring it directly to the battery and turning on the A/C? I don't ever seem to notice that the fan is on while driving... but it does turn on when I turn the A/C on. Is this normal?

As Kiwifriedpig said, the fans come on when they need to, this is normal. Forcing the to come on when not needed can be a bad thing. At speed the air flow is actually greater than what the fan can generate. Forcing the fan on at speed can be bad for it, and also reduce the air flow over the radiator.

[grndslm]

OK.. so,

- You *can* switch between synthetic to regular oil at any point, as long as it's a full flush.

- Switching to Straight SAE30 will help valve seal leaks, but it could possibly do more damage, so I should just repair the head and/or valve gaskets.

- Warm air has more benefits for the average putt putt car, but a race car that could handle higher compressions would easily benefit more from cold air??

- I highly doubt that 3 ounces of acetone could hurt my rubber seals when the acetone comes in a plastic case and most of these Japanese seals should be pretty high quality... and other cars are running a lot higher percentage of ethanol which should be more harmful than acetone...

But I also highly doubt I'm gonna be using it more than once, tho. It could possibly clear up quite a bit more than my trusty SeaFoam even.

- Drilled and sloted rotors should only be purchased from decent known manufacturers like Brembo, for example? Other ones will likely fail - have a crack attack...

- I expect most of my driving in the next couple months will be city driving, so I'm gonna keep the hood off. I rairly drive at 55mph nowadays, where it'd start to really add more drag. And for long distance ride's I'd definitely put it back on. Rain couldn't do much under the hood besides mess up my battery terminals and maybe a few other wires, whoopidy doo. Most of the time it'll be parked under a carport. It's also legal in my state, so cops can't do anything besides pull me over... and i've got nothin' to hide. =^D

- As stated, about by my fuel cap being fully tightened, I had gas shooting out near the fuel pump region (under backseat), and plugs (and wires that Firestone ghetto rigged) were getting soaked. I only leave the cap off just as little as possible and haven't had problems since, but if the fuel's running that much more rich, I might have to fix the fuel pressure regulator. Dunno... but I doubt it'd even be worth the price or trying to find it, 'cause it's prolly in some hard to reach spot. Hence me asking how serious of a deal this is, or could I be letting a lotta gas evaporate?

- I'm hoping my fan's alright. As long as I hear it one day with the A/C off, I'll be happy... but it's been a long time. I've started worrying more and more about this lately, but it's prolly ok. I usually don't leave my engine running for long, and when I do I'm haulin' tail with plenty of cold air keepin' the engine chil... so this could explain it.

ANYWAY, thank's for all the quick replies guys. They've helped tremdously so far!!

[curtis73]

Originally Posted by grndslm

OK.. so,

- You *can* switch between synthetic to regular oil at any point, as long as it's a full flush.

Doesn't matter at all if its a full flush or not. Synthetic and regular oil mix perfectly. You'll see a lot of oils on the shelf at the parts store that are half synthetic.

- Switching to Straight SAE30 will help valve seal leaks, but it could possibly do more damage, so I should just repair the head and/or valve gaskets.

You need to run the proper oil for your engine. Switching to a specific weigh of oil to prevent valve leaks is like cutting off your foot to prevent foot pain. Run the proper oil and fix the leak... or just run it like it is and put up with the leak.

- Warm air has more benefits for the average putt putt car, but a race car that could handle higher compressions would easily benefit more from cold air??

doesn't really matter. Cold air is denser, meaning it has more molecules of oxygen per cubic foot of air. If you want to reduce emissions and save fuel, use hot air. If you want to make a couple more HP use cold air.

- I highly doubt that 3 ounces of acetone coud hurt my bber seals when the acetone comes in a plastic case and most of these Japanese seals should be pretty high quality... and other cars are running a lot higher percentage of ethanol which should be more harmful than acetone...

Rubber and plastic are two completely different things. Rubber comes from plant sources and plastic comes from petroleum. Acetone will eat rubber in very short order. Combine that with the fact that it does nothing for your car and just skip the acetone thing. It ranks right up there with the water-fueled car.

But I also highly doubt I'm gonna be using it more than once, tho. It could possibly clear up quite a bit more than my trusty SeaFoam even.

stick to the seafoam. If acetone worked better than seafoam, then the scientists at seafoam would be using acetone instead of what they are using.

- Drilled and sloted rotors should only be purchased from decent known manufacturers like Brembo, for example? Other ones will likely fail - have a crack attack...

I have drilled rotors on my car and they are totally pointless. On a street car they are about as usefull as race tires. Drilled/slotted rotors are designed to carry away the gasses put out by the pads against the rotors. The thought is that by having a place for the gasses to escape increases the pad's ability to contact the rotor. It works great, but on the street its SO pointless. You will never notice the difference, your rotors can only be machined once if at all, and they make more noise. Skip it.

- I expect most of my driving in the next couple months will be city driving, so I'm gonna keep the hood off. I rairly drive at 55mph nowadays, where it'd start to really add more drag. And for long distance ride's I'd definitely put it back on. Rain couldn't do much under the hood besides mess up my battery terminals and maybe a few other wires, whoopidy doo. Most of the time it'll be parked under a carport. It's also legal in my state, so cops can't do anything besides pull me over... and i've got nothin' to hide. =^D

You'll waste fuel, screw up your aerodynamics, and reduce your car's safety in a crash... but if you think it looks cool, go for it.

- As stated, about by my fuel cap being fully tightened, I had gas shooting out near the fuel pump region (under backseat), and plugs (and wires that Firestone ghetto rigged) were getting soaked. I only leave the cap off just as little as possible and haven't had problems since, but if the fuel's running that much more rich, I might have to fix the fuel pressure regulator. Dunno... but I doubt it'd even be worth the price or trying to find it, 'cause it's prolly in some hard to reach spot. Hence me asking how serious of a deal this is, or could I be letting a lotta gas evaporate?

uh... alert.. the problem is not because your cap is too tight, there is a leak in your fuel system. DON'T let that continue. If you value your car in any way at all, fix it RIGHT. Jeez... loosening the gas cap because the pump leaks??? If you don't fix it, make sure you have a really good life insurace policy so when you die in a fireball your friends have some money to spend.

- I'm hoping my fan's alright.

Don't worry about it. Watch the temp gauge. As long as it doesn't go past about 230 you're fine.

ANYWAY, thank's for all the quick replies guys. They've helped tremdously so far!![/quote]

[grndslm]

- So, I'm assuming that auto parts stores all say you can't switch from synthetic back to regular so they can get more money from me?? I was gonna by the SAE30, but they said nooo, nooo, nooo... you must stick with synthetic or synthetic blend. I'll just keep using synthetic and do the head job when I get a chance.

- Is there anything better than Seafoam?

- I'm really not expecting that much of a decrease in fuel consumption with the hood off, but we'll see soon enough.

- And I'm not so much sure there's a leak in the fuel pump as it is just the tank in general. There's a lid to the tank under my back seat with an electrical connector/socket. *That* is where gas shoots out of... straight in that socket and it shuts my car off while I'm driving. Hence, my belief that it's the fuel pressure regulator and my best solution temporarily is to leave the cap off just a tad, giving it some breathing room.

[curtis73]

Its not the fuel pressure regulator, its a leak. It doesn't matter what the problem is, you have open fumes that are going to go boom. Sometime someone is going to walk past your parked car, flick a cigarette and kill three people and send your car to a firey grave.

[Moppie]

Originally Posted by grndslm

- And I'm not so much sure there's a leak in the fuel pump as it is just the tank in general. There's a lid to the tank under my back seat with an electrical connector/socket. *That* is where gas shoots out of... straight in that socket and it shuts my car off while I'm driving. Hence, my belief that it's the fuel pressure regulator and my best solution temporarily is to leave the cap off just a tad, giving it some breathing room.

Thats the fuel pump.
Those wires are carrying 12 volts, more than enough to generate a spark.
For some reason the pump is leaking, so fuel is being spilled around the wiring.
The same wiring that is carrying more than enough voltage to generate a healthy spark.
You figure it out.