regular unleaded in 350z?

Post by **wildpig** » Sat Feb 26, 2011 3:15 pm

I know. Not a good question, but with gas price going up, just wondering if thats even a possibilty without engine blowing?

Post by **tollboothwilley** » Sat Feb 26, 2011 4:07 pm

It is possible. If you do - then don't drive it hard. If it starts to ping then switch back. Most people wont do it other than long drives for a full tank.

It is possible that it could cause knock and overtime could do damage to the engine. However, there are some guys that have been doing it for over 100K miles and the entire time they drive using 87 octane with no problems.

Post by **wildpig** » Sat Feb 26, 2011 4:46 pm

i don't plan to track it or anything. just driving to and from work. with all the gas price going up like this my pathfinder is getting such a pityful 18mpg that i am considering getting a 350z just to have better mileage. I know, you probably say i should get like a sentra or something if i want better mileage but i want some sportiness too.

Post by **BusyBadger** » Sat Feb 26, 2011 5:01 pm

You'll be saving what, 15 to 20 cents a gallon? Don't run regular in your Z. I've done it twice when I stopped somewhere and couldn't get premium, but if you make a habit of it you'll end up hurting your car in the long run.
'

Post by **wildpig** » Sat Feb 26, 2011 8:38 pm

i guess that will be a difference of about $4 per tank. Given that the Z gets about 26mpg, i would still be spending less money on gas than my pathfinder....

YouTube · Post by **dasoupdude** » Sat Feb 26, 2011 9:55 pm

I had to put 87 a few times in my car, it was during the hurricanes when gas was scarce. I tell ya, I sort of cringed at the sight of that flowing into my car.

Gas door and owners manual say " recommend premium fuel: for optimum performance" or something like that at least. Sure you can get away with lower grade gas (I wouldn't recommend going lower than 89, (There are g35 and Z owners out there that ONLY put 87 in and they seem to be fine) but you should at least drive a bit more conservative so you don't harm anything down the road.

If you are a SPIRITED driver, even slightly..keep feeding the Z its premium kibbles n bits.

Post by **wildpig** » Sat Feb 26, 2011 10:02 pm

that's what it says on the gas door and manual for my 02 pathfinder too. I've been putting in reg unleaded and it's been running fine. I do drive like a grandma with my pathfinder. i;ve never rev engine above 2k rpm while accelerating, reaching a maximum of 2.7k rpm when crusing at 70-80 mph.

having said that, even using 89 plus grade, with the fuel eco of the Z, i would still save a considerable hundreds buck each yr even though i only drive about 9k miles/yr...

Post by **Ace2cool** » Sun Feb 27, 2011 4:29 am

If you're that concerned about gas prices, you shouldn't really be driving a Z, IMHO.

The fuel costs are apparent when you buy the car. The dealership doesn't try to hide anything. Low fuel economy, high fuel price due to the recommendation of premium, ect.

The whole purpose of the higher octane fuel is to resist detonation in the higher compression engine of the VQ35. Same recommendation went for the high compression VG30, turbo'd VG30DETT, still applies for the VQ37, ect. When you force more air into an engine, the fuel has more of a tendency to pre-ignite, or detonate.

That's where your knock sensor comes into play. When the engine detects detonation (knock, ping, pre-ignition), it automatically retards the ignition timing to help prevent damage. When you retard the timing, you get a lower power output, obviously.

Now here's where it gets tricky: You can actually get worse gas mileage by switching to regular unleaded! I've used regular 87 in my 2+2 for a fill-up before, back when the hurricanes made premium scarce, and I documented my mileage. On 93 octane, I average 21 mpg, 23 mpg highway. When I had to use 87 octane, I averaged 18 mpg, 19 highway! on a 16 gallon tank, that's a lost mileage of 48 miles total, or 2 gallons of fuel! So yes, the tank will be cheaper when you're swiping your card, but will it really be in the long run, after factoring in lost mileage, lost performance, and possible repairs caused by complications of using a lower grade fuel?

Granted, on a Z33, the mileage drop might not be as severe as in my Z32, but you will lose performance and mileage, since the engine won't be operating at its optimum performance level, and thus, will have to do more overall work to compensate for the lost performance (the engine has to work harder to get from A->B).

So based on fuel costs alone for me and my mileages:
We'll use $3.50 for regular
And use $3.70 for premium, as most places are $.20 more for premium

16 gallon fill-up on premium @ $3.70: $59.20
16 gallon fill-up on regular @ $3.50: $56.00
TOTAL SAVINGS: $3.20

Now factor in that 2 gallons of fuel @ $3.50: $7.00

NET LOSS: $3.80

NOTE: These were my findings on a Z32. The Z33 may respond to regular fuel better, but I highly doubt it, seeing as it is a high compression engine that highly recommends premium fuel. Wow, that was a long post.

Post by **wildpig** » Sun Feb 27, 2011 10:37 am

ace, love that Twin turbo z you got

. I hvnt been able to find too many of those .... definitely give a new 350z a run.

well i was thinking about running an experiment like that on my 02 pathy too. Getting 18mpg on reg unleaded now. I wonder if it will be 20mpg switching to premium. funny thing is as gas gets more expensive and if the difference between premium and reg stays constant at 20 cent difference and if there is better fuel eco of 2mpg, it actually pays to use premium....

guess i will hv to test that out...

Post by **BusyBadger** » Sun Feb 27, 2011 5:20 pm

dasoupdude wrote:I had to put 87 a few times in my car, it was during the hurricanes when gas was scarce. I tell ya, I sort of cringed at the sight of that flowing into my car.

I made it a habit of keeping some octane booster with me just in case when that was going on. Places that were out of 92 did happen to have some 89 on hand though.

Post by **370Z/28** » Mon Feb 28, 2011 9:08 am

wildpig wrote:i guess that will be a difference of about $4 per tank. Given that the Z gets about 26mpg, i would still be spending less money on gas than my pathfinder....

26mpg

I'm averaging 18.5 in my car so far. Hoping as things "losen up" and I get better with my stick I'll improve some. I was hoping for 20. That is what I got in my G.

Post by **wildpig** » Mon Feb 28, 2011 12:40 pm

18.5 mpg? that must be city mileage. 26 mpg is the highway mileage.

Post by **370Z/28** » Mon Feb 28, 2011 1:47 pm

Yup....stop and go....stop and go.

Post by **wildpig** » Tue Mar 01, 2011 1:53 am

Ya, 18.5 mpg sounds about right on for stop and go. Depend on how much stop and go and of course how hard you drive it, hard to improve your mileage that much unless you completely drive like a grandma which is hard to do in a 350z with stick shift

Post by **370Z/28** » Tue Mar 01, 2011 6:55 am

No grandma driving for me.

I'm so happy to have a stick again, I pull all the gears hard. It is so much fun.

Post by **wildpig** » Sat Mar 05, 2011 1:32 am

I guess so. I don't drive a stick often enough, but I have a feeling when I do drive a stick I do tend to let the rpm goes a little higher before shifting than the automatic usually shift when i drive an automatic. I have a feeling that's how it is with most drivers too.

Post by **BusyBadger** » Sat Mar 05, 2011 9:34 am

I usually don't let wind the tach up more than 4K in normal driving, even lower than that after the first crank of the day.

There have even been a couple of times (like when I couldn't find premium anywhere...we've come full circle!) that I wouldn't let the tach get above 2250 or so because I was staring down a low fuel warning and I was in the middle of nowhere in the mountains and wanted to make the most use of what I still had in the tank.

I know, hypermiling a Z.

Post by **wildpig** » Sat Mar 05, 2011 12:57 pm

must be hard to restrain yrself from going above 2.3k rpm in a car like 350z

Post by **NSRsheets** » Tue Mar 08, 2011 9:32 am

Like what most people are saying don't get a Z if your not going to run premium.

Post by **wildpig** » Sat Mar 12, 2011 5:11 pm

i tried half tank of premium in my 02 pathy. Fuel economy didn't change. It does feel smoother accelerating from start. Also it was cool to see the effect on the ignition timing advance which was about 20 degrees on premium. On regularfuel, ignition advance is retarded to 30 degrees...

Post by **TISon28s** » Sat Jun 04, 2011 7:10 pm

I usually put regular for long trips. No problems whatsoever, still drove fine.

Post by **nnismo03** » Mon Jun 06, 2011 10:13 pm

Hell to the no!! Putting lower grade fuel makes your ride run rough. Its not good for the car. Gas saving tips just don't drive it like you stole it and keep your maintenance up and you will conserve fuel.

Post by **jerryd1987** » Sat Aug 13, 2011 7:43 pm

BusyBadger wrote:
dasoupdude wrote:I had to put 87 a few times in my car, it was during the hurricanes when gas was scarce. I tell ya, I sort of cringed at the sight of that flowing into my car.
I made it a habit of keeping some octane booster with me just in case when that was going on. Places that were out of 92 did happen to have some 89 on hand though.

except you would need like 10 bottles of the stuff to take it from 87 to 88 octance(dont believe everything the bottle tells you look at the ingredients and look up there octance ratings vs how much your adding into the fuel. if you want a easy way to raise octane go to ace hardware and buy 5 gallons of 100% pure xylene its 117 octane and is the same thing the distillery puts in to make 87 into 89,91,92, or 93 its just a little more xylene or toulene(toulene is only 114 octane though) just figure how much you need to add to your fuel based on what you want your octane. for instance 4 gallons 87 + 1 gallon xylene = 93. not really economical but if you cant get it just saying for future referance.

Post by **Ace2cool** » Sun Aug 14, 2011 11:33 am

I've heard of toulene before. Exactly how safe is the xylene for the fuel system?

Post by **BusyBadger** » Sun Aug 14, 2011 12:32 pm

There's a good thread on xylene over at LS1Tech. What Jerry probably didn't think about when he decided to quote me and go on and on about octane boosters is that I never actually said what I was boosting my octane with.

You pick up all sorts of fine info living in the NASCAR Belt.

And here are some nice DIY recipes from the Buick GN folks.

Post by **Ace2cool** » Mon Aug 22, 2011 8:55 am

So xylene is basically toulene on steroids, for the exact same price. Werd. I think I may pick up a can to see how it improves the feel of the car. After all, the Z32 was designed to run on 95 octane (97 where available in Japan)

Post by **300ZXttZMAN** » Mon Aug 22, 2011 5:55 pm

screw running cheap gas man you will so regret it

Post by **300ZXttZMAN** » Mon Aug 22, 2011 5:56 pm

More lead is a bad thing and thats what that cheap s*** has..

Post by **Ace2cool** » Sat Aug 27, 2011 12:38 pm

Lol, Mark, gas hasn't had lead in it since the '60s.

Post by **orangeNblue** » Mon Aug 29, 2011 5:18 am

You ever try that xylene combination?

regular unleaded in 350z?

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