Lesta3474 Posted November 19, 2008 Report Share Posted November 19, 2008 Hi Guys, I recently got myself a fresh import from Japan. Its a standard Nissan Silvia S15 Spec S 1999. Everything is factory standard so no funky modifications or anything like that. My question what fuel should I be using. At the moment I'm using 95 V power from Shell but i Understand that High Octane for a car that does not require high octane is not good as well. Anyone have any clue? I'm leaning towards 95 octane but I do not know the compression rate of the car and therefore I do not know. Help! Quote Link to comment Share on other sites More sharing options...
lmsmith Posted November 19, 2008 Report Share Posted November 19, 2008 91 will be fine for it, but ultra or something will help it to run smoother and more consistently. Don't use ethanol blended, sometimes it can condense and let water into the fuel. Quote Link to comment Share on other sites More sharing options...
ryanjury Posted November 19, 2008 Report Share Posted November 19, 2008 Nice car Jappers are mapped to run on 100 or 104 octane (from memory but its higher than what we can get).. Unless your car has been remapped for a lower octane fuel get the highest you can, this is more important for higher performance turbo cars.. When I had my GTIR, WRX, GTX etc I always ran them on the BP ultimate but I think that other servo's have introduced 98 octane fuels now I am sick of spending my money on cars and drive a crapper I don't really follow it anymore.. Good luck and enjoy the new car Quote Link to comment Share on other sites More sharing options...
Lesta3474 Posted November 19, 2008 Author Report Share Posted November 19, 2008 Thanks for the reply guys. No clue whether the engine has been remapped or not. I would say no because i doubt that the dealer would spend money on that. Its a non turbo so naturally it will have a lower compression rate I would suspect. So far 95 octane has not caused any knocking in the engine... so I know that its definitely not requiring any higher... Just worried that its too high as it might cause ill effects to other parts of the engine. Quote Link to comment Share on other sites More sharing options...
markoshark Posted November 19, 2008 Report Share Posted November 19, 2008 I try and use 95 octane when i go on longer trips, more power = good Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 91 will be fine for it LOL!!! The MINIMUM octane they get at the pump in Japan is 98, you'd be better off running it on a mix of vodka and meths than 91. IIRC the compression ratio of the SR20DE is a touch over 10.0:1, so although it may run alright on 95, you will get better performance and economy by running it on 98 (either BP Ultimate or Mobil Synergy 8000). The guys at www.nissansilvia.co.nz would probably be more helpful if you've got any more question. Nice car, shame it isn't an R-spec tho! Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 Its a non turbo so naturally it will have a lower compression rate I would suspect. Nope, the SR20DET has around 8.5:1 CR and the SR20DE is around 10.0:1. Turbo motors generally run less compression for better reliability. You certainly won't harm it by running higher octane fuel (not avgas though, the lead will ruin the oxygen sensor). By the time you notice the knocking it could be too late, if you're really concerned about how it runs on the 95 octane you could take it somewhere like Speedtech in Wellington and do a dyno run to get a readout of your air:fuel ratios to make sure it isn't running lean. Quote Link to comment Share on other sites More sharing options...
Lesta3474 Posted November 19, 2008 Author Report Share Posted November 19, 2008 Running lean as in not burning clean? How much does it cost to get a dyno test? Thanks! I've also just posted a thread on the silvianz website. And i emailed [email protected] for a manual! Doubt they can help me though. Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 Running lean is the opposite of running rich, ie too much air and not enough fuel (rich = too much fuel). Not sure what a dyno run costs these days, used to be about $50 but could be more now. You'd be best to go to a place with a rolling road type dyno and not a hub dyno as the set up costs will/should be less. You should get a print out showing your peak power and torque (at the wheels) and the air:fuel ratios. In all honesty though, its probably just a waste of money when you could run the car on 98 and know you won't have any problems. Oh, and just a thought, a modern engine like that will almost certainly have a knock sensor that will retard the timing a little if it does start knocking, so you probably wouldn't even hear it. Quote Link to comment Share on other sites More sharing options...
Lesta3474 Posted November 19, 2008 Author Report Share Posted November 19, 2008 Fair enough. I'll try 98 after the 95 runs out. Its currently at 1/4 so nearly there. I hope I've not done something bad to the engine. Quote Link to comment Share on other sites More sharing options...
rockwork Posted November 19, 2008 Report Share Posted November 19, 2008 i dont see how you would have done anything bad i run my 99 subaru b4 on 91 and its fine. once a month i will do a tank of 95. i dont put 98 in it cos all it does is cough and splutter and runs like crap. Quote Link to comment Share on other sites More sharing options...
lmsmith Posted November 19, 2008 Report Share Posted November 19, 2008 LOL!!! The MINIMUM octane they get at the pump in Japan is 98, you'd be better off running it on a mix of vodka and meths than 91. IIRC the compression ratio of the SR20DE is a touch over 10.0:1, so although it may run alright on 95, you will get better performance and economy by running it on 98 (either BP Ultimate or Mobil Synergy 8000). The guys at www.nissansilvia.co.nz would probably be more helpful if you've got any more question. Nice car, shame it isn't an R-spec tho! In Japan, they also run ethanol blended high octane petrol, so in reality, the octane doesn't matter too much. The real difference between 91 and 104 or whatever in between is the price, and the smoothness of the car when you're driving. You're not going to do any damage using a lower octane fuel - remember, most Jap cars have "ideal" cruising speeds if 150+km/h which we don't do, and an "ideal" situation is the car running at certain outside temperatures etc. High performance cars have higher compression (so they have high HP), and require higher octane fuel. However, a 1999 ANYTHING isn't so high performance that it requires a high octane fuel in order to get good performance - unless you are racing the car or intend on keeping the engine in perfect condition as a classic one day, you're wasting your money buying 98 octane when 91 or 95 will do perfectly fine and will not damage the engine at all. The 1999-2001 S15 have a lower tuned ecu, so are designed to have a lower octane fuel. Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 i dont see how you would have done anything bad Simple science lesson; octane rating refers to the length of the fuel molecule, the higher the number the longer the molecule and the longer it takes to burn. So when running a lower octane fuel it will burn quicker than a higher octane fuel, meaning in high compression or forced induction motors you increase the chance of running lean, which causes heat and in bad cases can lead to all sorts of problems. That is how running a lower octane fuel can damage en engine. In normal day-to-day situations the difference between 91 and 98 is probably not great enough to cause any serious damage, maybe just cost you a bit of power as the computer adjusts the timing for lower quality fuel. But, if something goes wrong (say the hose to your wastegate actuator pops off causing your boost to spike) you have a lot less margin for error and things could go wrong quicker. If your car is running better on 91 than 98 and "coughs and splutters" then you should probably get it checked out as there could be a problem. Or first you could try resetting the ECU when you fill up with the higher octane fuel. Quote Link to comment Share on other sites More sharing options...
rockwork Posted November 19, 2008 Report Share Posted November 19, 2008 If your car is running better on 91 than 98 and "coughs and splutters" then you should probably get it checked out as there could be a problem. Or first you could try resetting the ECU when you fill up with the higher octane fuel. i get my car checked all the time and it is serviced regularlly. and zane is a mechanic. i have also had a fuelstar installed which may help. it adds lead to the fuel to increase horse power and make it more economical. there is nothing mechanicaly wrong with my car it just does not run right on 98 Quote Link to comment Share on other sites More sharing options...
paul_r Posted November 19, 2008 Report Share Posted November 19, 2008 i used to have a s14 silvia, ran fine on both 91 and 98. motor was still sweet, compression tests etc ocnfirmed that. only thing i noticed was 98 had a wee bit more power and a tiny bit more economical Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 You're not going to do any damage using a lower octane fuel - remember, most Jap cars have "ideal" cruising speeds if 150+km/h which we don't do, and an "ideal" situation is the car running at certain outside temperatures etc. High performance cars have higher compression (so they have high HP), and require higher octane fuel. However, a 1999 ANYTHING isn't so high performance that it requires a high octane fuel in order to get good performance - unless you are racing the car or intend on keeping the engine in perfect condition as a classic one day, you're wasting your money buying 98 octane when 91 or 95 will do perfectly fine and will not damage the engine at all. So you're suggesting I could run a 1999 Civic Type R with a 10.8:1 CR and 9000rpm redline just as well on 91 as on 98? :-? I agree you could probably run it on that fuel, but it certainly wouldn't be ideal nor would it make as much power. In fact I KNOW from experience that it would make a noticeable difference in the way such an engine would run, and if it was my car and for some ungodly reason I could only put 91 in the tank I certainly wouldn't be using WOT or taking it anywhere near the redline. And what does cruising speed have to do with anything? As I recall Japan has a 100kmh speed limit just like us, even on their fantastic express ways. The 1999-2001 S15 have a lower tuned ecu, so are designed to have a lower octane fuel. Could you explain what you mean by "lower tuned"? Rockwork why on earth would you want to add a fuelstar to a modern car? Adding lead to the fuel will simply ruin your oxygen sensor (and others) and that could explain why your car is coughing and spluttering. Quote Link to comment Share on other sites More sharing options...
rockwork Posted November 19, 2008 Report Share Posted November 19, 2008 my car ws coughing and that before the fuelstar. and the new fuelstars are designed for new high performace cars. im not silly and read up on all the info before having it put in. Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 I was under the impression that fuelstar was something added to older cars designed to run on leaded fuel to help them run on unleaded without ruining the valve seats, I've just had a quick read over their website and obviously its a bit more than that. It still seems strange that the car runs poorly on 98, there's probably nothing mechanically wrong with it, the problem is more likely to do with the ecu/fuel management system (if there is a problem). Quote Link to comment Share on other sites More sharing options...
rockwork Posted November 19, 2008 Report Share Posted November 19, 2008 a 1999 type r civic should at least be running 11:1 so some thing up with that. i also have an 1996 celica that is run 91 at 12:1 com and dose the quarter mile in mid 11sec it has 300bhp at the wheels and im running a fuelstar in that as well. o and i got it wrong the fuelstar adds tin not lead to the fuel which makes it burn cleaner. Quote Link to comment Share on other sites More sharing options...
lmsmith Posted November 19, 2008 Report Share Posted November 19, 2008 Lower tuned - speced for lower high performance (gear ratios, top speed ect). Of course a car isn't going to perform as well on lower octane fuel. The whole point of high octane fuel is that it doesn't ignite at low compressions, so you can get a better performance out of the car. However, the average person who isn't pushing their car is not going to notice a big difference driving normally, and certainly isn't going to damage their car. Top speed is relevant because it helps to demonstrate the specs of the car - and how the average driver is not going to get close to the limits of the car where the difference between 91 and 98 is going to be noticed. Quote Link to comment Share on other sites More sharing options...
rockwork Posted November 19, 2008 Report Share Posted November 19, 2008 Lower tuned - speced for lower high performance (gear ratios, top speed ect). Of course a car isn't going to perform as well on lower octane fuel. The whole point of high octane fuel is that it doesn't ignite at low compressions, so you can get a better performance out of the car. However, the average person who isn't pushing their car is not going to notice a big difference driving normally, and certainly isn't going to damage their car. Top speed is relevant because it helps to demonstrate the specs of the car - and how the average driver is not going to get close to the limits of the car where the difference between 91 and 98 is going to be noticed. well said Imsmith Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 Top speed is relevant because it helps to demonstrate the specs of the car - and how the average driver is not going to get close to the limits of the car where the difference between 91 and 98 is going to be noticed. You didn't say anything about top speed, you said cruising speed. So what you're saying is that if you're just cruising about and aren't too concerned about the performance of your car and aren't likely to put your foot down then your car will run ok (not great, not good, just ok) on 91? I'm not sure what you're basing your statements on, but I have found in several of my cars (NZ-new and JDM integra type r, eg6 civic with both b16a and jdm b18cr, mazda gtx) that the different between 95 and 98 is noticeable in both performance and economy, even just on the open road. Maybe I'm not an "average driver" though, and I certainly appreciate my cars running better than just ok. Rockwork, the EK9 (97-00 Civic Type R) comes with a b16b motor, which has a CR of 10.8:1. Have you got any pics or videos of the celica? It sounds pretty mad! I'm presuming it is naturally aspirated with a CR that high, so 300bhp is pretty impressive out of a 2L motor, and mid 11's even more so. Having been in the honda scene for years now and having followed Andrew Johnsons progress building up his civic to run mid 11's while still being NA and street legal, I appreciate how hard it is to make a non turbo front wheel drive quick down the 1/4 (which is why a lot of honda guys are more into circuit racing now). Where abouts did you run that time? Excuse me for being a little sceptical, but it is a big claim for a heavy car like a celica! Are you going to be competing at any of the nightspeed drag wars this season? Quote Link to comment Share on other sites More sharing options...
lmsmith Posted November 19, 2008 Report Share Posted November 19, 2008 Sorry, you're right, I meant to say top speed not cruising speed. Although cruising speed is relevant too - at your ideal cruising speed, your car is most economical, quietist and smoothest. My statements are based on the fact that the average New Zealand driver is terribly uneconomical, has no idea how a good car is driven, and has marginal - at best - driving skills. You obviously care about driving, and the performance of your cars, and you're a bit pedantic, so I can make an educated guess that you're probably a better than average driver (even if you are a Honda fan ). However, you have to agree that the way the average driver drives, there's no way they would notice the difference between 91 and 98 octane fuel - they probably have 3 soft tires, unaligned wheels and completely screwed gears, and drive only in straight lines, even around corners. They also probably haven't driven a car at top performance, so have nothing to compare their car to. Quote Link to comment Share on other sites More sharing options...
David R Posted November 19, 2008 Report Share Posted November 19, 2008 LOL I would certainly agree with that!! Not sure about wellington, but Auckland is becoming a pretty hazardous place to drive (except for at 5pm when no one is going fast enough to do any damage). Dodgy garages offering $20 WOF's make me wonder about the standard of the cars on the road too... I hope though, going by the fact he cared enough to make a post about it, that the OP is not one of those people and actually gives a damn about how his car! Quote Link to comment Share on other sites More sharing options...
rockwork Posted November 19, 2008 Report Share Posted November 19, 2008 hi i did it on a test track at the back of a m8s farm (privately own strip) as for a heavy car it weiged 1230kgs have lightened it a bit it now is under 1000kgs as for night wars no im not competing as i am to busy at work and yes it is NA ill put a pic up l8r but it and old one when i was making my own wide body kit as for the subaru i dont drive it like a nana and i do put my foot in to it even so i am a female dosnt mean i dont give it the boot Quote Link to comment Share on other sites More sharing options...
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