new admission, smarts can run on regular...

Posted by mr bad example on April 23, 2008 at 10:43pm in Support/Questions & Answers

"The Smart Fortwo Uses Premium Fuel ...
Dave Schembri, president of Smart USA acknowledges premium fuel is recommended however he said “you could use regular gas — there’s no damage to the car.” According to sources with the engines high compression ratio, premium fuel with higher octane levels burns more economically and the MPG would improve approximately 2 MPG. "

(a smart has a 10:1 compression ratio, that's like NORMAL for most engines in the last 20 years for a normal engine, turbos go a little lower, diesels are like 20+:1)

the funny thing is premium 92 fuel is 10% more in cost, for a maybe a 5% (at 40mpg) loss in mpg. where i live (NE illinois) premium is knocking on $4 a gallon and i can get cheapo gas for $3.60. in the owners manual, they recommend if you gas up on low octane, keep it below 3000rpms, well, that's 60mph in a stock smart. i got 90 miles on this tank and it's reading 7/8's full, next time i gas up, i'll use regular, in my silly commutes i've been getting 41mpg (today, 15 miles in 1 hour! crawls and long stops). Schembri admits "no damage can occur to the engine, just a marginal loss of MPG... (maybe 5%) i'm filling up on 87 octane next time!

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Permalink Reply by smartster on April 23, 2008 at 11:32pm: Hmmm, strange that David would say that, I have some more data based on all the testing and tuning we've been doing and the actually data is a lot different.

The smart is actually running 11.4:1 compression and the engine runs a little lean to keep the gas ratings high. This is why using normal gas causes problems especially in high RPMs and high speeds and the engine will lean out, now is you leave the smart stock and run on normal gas and drive like most of the population that has the smart which is city only driving then probably your ok.

If you put a new muffler, new intake and drive the smart hard, on normal gas, even 91 octane and you'll probably get to know your service manager very well at your local smart center. On the positive side the smart has gotten up to 130 horsepower at the wheels (dyno tested/proven) but the air/fuel mixture is an issue.

This is actually a big issue for us, even tonight was on a call with one of the race teams that runs Le mans style cars about how to get around this issue with the smart, as lucky enough one of the teams loves the smart and helps me out, got some great advice and we think we have some solutions but they aren't something that would be available to the public, so lets just say the smart has some issues with gas, air and performance upgrades.

I've also talked with David Schembri and in our talks he was very worried about how the smart will holdup with upgrades and high speeds/high RPMs, will be at smart USA headquaters next week maybe they'll have a solution on their end also :); ▶ Reply to This

Permalink Reply by smartster on April 23, 2008 at 11:35pm: Update

the 10:1 is the tubro version of the smart, had to go back into our technical data to figure out where that # came from, but I know 100% that the smart we have here in the US/Canada is 11.4:1; ▶ Reply to This

Permalink Reply by Carlos 1 day ago: Strange right? The octane in CA is not the same as in USA?
In Europe we have 11:4 for the 71BHP version. In the press release, smart said clearly that they lower it for the US market.; ▶ Reply to This

Permalink Reply by mr bad example on April 23, 2008 at 11:43pm: well i got this quote from http://smartcarofamerica.com/ i thought i saw a 10:1 compression ratio somewhere. i found it, Road & Track lists the smart's compression ratio as 10:1 for the US version (i did, i did saw a 10:1 compwession watio!!!) look it up!; ▶ Reply to This

Permalink Reply by mr bad example on April 23, 2008 at 11:46pm: i've seen messages elsewhere that the mistu engine runs fine on 87 octane and "our fuel expert" here has stated the same thing a couple days ago, now Schembri says the smart will do no harm on 87 octane...we're getting a whole lot of mixed messages here!; ▶ Reply to This

Permalink Reply by mr bad example on April 23, 2008 at 11:48pm: look it up, http://www.roadandtrack.com/article.asp?section_id=3&article_id... go to data page!; ▶ Reply to This

Permalink Reply by smartster on April 23, 2008 at 11:59pm: Wow I guess you in the US might be getting a little raw deal from smart, there are a few things that are different on this stat sheet that I know are wrong for the smart I have in Canada:

1) top speed, they say 90mph* (I do my runs at 100mph)

2) 1/4 mile, while it could be a bad driver, but I run in stock format low 18's, they say 19.2, have not run a 1/4 mile with performance parts on yet.

3) they say the engine is 1,000 CC, but its not its 999cc, so much for accuracy.

4) fuel capacity they say is 8.8 Gallons, but its 10.

Ok so they got 4 things wrong, maybe/hopefully they got the compression wrong also.; ▶ Reply to This

Permalink Reply by mr bad example on April 24, 2008 at 12:04am: i wonder the same thing, some say the tank has 8.7 gallons including the 1.3 gallon reserve, i've never been below 1/4 tank and that was around 6 gallons (1000/999 is a fudge factor thingy) but i've seen 10 gallon total. i wonder if that would mess up the scan gauge? R&T is usually right on with their info. i'm running 87 on my next fill-up!
so many questions!!!!; ▶ Reply to This

Permalink Reply by smartxs on April 24, 2008 at 2:40am: Per the sales brochure for the 2008 Smart (US)
Engine sizw 999cc
52kw/70 hp @5800rpm
68lb-ft @ 4500rpm
2.83 bore X 3.22 stroke (inches)
10.1 compression ratio
Multipoint FI
90 mph top speed (electronically limited)
12.8 second 0-60mph
fuel type Premium Unleaded

From my VW Vanagon w/air- and water-cooled engine experience - if you drive highway the engine will last about 20,000 miles longer with premium fuel, low speed (low rpm) driving it made no difference, but this was with 9:1 compression and before the computers could control 'knock'.

I have run my Mercedes on regular unleaded with no adverse effects and my Honda Pilot on regular with no adverse effects - both have Premium recommended. Both have ECUs that control knock.

Ditto for my VW Eurovan, our BMW Z-3, and motorcycle (except for the computer control of knock for the motorcycle). My wife's Acura RDX is the only vehicle we have that demands a higher grade fuel with knocks and missing, so it gets it.

Miles: Mercedes 161,000
Eurovan 170,000
Pilot 84,000
motorcycle 24,000
Camry 36,000
Acura RDX 17,000
Z-3 35,000
Vanagon 144,000 before Top end Overhaul but no longer have it.; ▶ Reply to This

Permalink Reply by smartster on April 23, 2008 at 11:50pm: Every strange, well maybe the US gets the turbo engine minus the turbo, which would mean damn it will be a slow car and if the car has that low compression then yes you could run 87 on the stock smart in probably all type of driving without issue.

But I know for a fact that the Canadian 451 smart's are 11.4:1 compression, boy if they put the other engine in the US smarts that would be really interesting and sad for the US smart owners.; ▶ Reply to This

Permalink Reply by midnight_crossing on April 24, 2008 at 9:45am: Well apparently the cars in Canada and the US are different because we can't sell our smarts to the Americans. I asked my dealer... I said, so... I'm just going to eBay my car if I can't get white and he said sure, Dee, that's fine, but they won't register a Canadian car for the US market. Its not the same car that they are selling. Hmmmmm, go figure. I guess that's why we are paying more for our smart in Canada. I guess I'm ok with that. At least I don't have to wait 2 year for one. :); ▶ Reply to This

Permalink Reply by Daniel Coté on April 24, 2008 at 1:55pm: "... well maybe the US gets the turbo engine minus the turbo, which would mean damn it will be a slow car ..."

The glass half full view is that we may be able to more easily/safely add the turbo plumbing to our cars,; ▶ Reply to This