^ This. I've found that even the quality of "93 octane" varies from location to location. That said, I've had plenty of 500whp cars last years on 93 octane... Ours made 475 on 92 and the tear down showed minty fresh internals, so 25hp more on 93 doesn't seem like it's far fetched to me.

 

I still can't believe the pump gas comments. So what, everyone with a turbo kit or SC kit making over 400whp just fills up with race fuel all the time?? Why the hell would the average Joe that uses the car for fun or as a weekend warrior even buy a kit then if they can't make somewhat decent power without having to worry about the engine blowing apart because they use pump gas? A car with forged internals should be more than capable of handeling 400-500whp reliably on pump gas in combination with a tuner who knows what he's doing.

 

Could have been a bad batch of fuel as well... would be interesting to have its octane tested.

 

Ive gathered that there seems to be a very general mark of about 25hp-35hp difference with 1 point OCT increase/decrease, so your assumption seem consistent with that. That could mean as much as 70hp difference between 91-93 pump. So not all pump is as "pissy" as others . Its all about preventing detonation, and fuel OCT is an important part as it ultimately sets the ceiling, but a sub par cooling system or tune can be the premature limiting factor in ultimate output seen for the particular running environment. Some tuners will never tune to the fuels full potential, and usually for good reason becuase its risky when the other factors that can cause denotation are not always controllable. Heat or boost fluctuations being the biggest killer.

 

On a stock 11:1 compression motor 400ish is it.. At least on most east coast 93 octane. Drop a point or 2 in compression and you can do 500. Beyond that it gets scary. You're pushing the limits on what the fuel can do. When you approach those limits motors melt.

 

Soooo...what you're collectively saying is that...consistent octane fuel and a good tune are the difference between having a problem or not having any issues with boosting your stock engine on your S2000. The fuel is a variable, not the catalyst for any particular outcome. So is a driver that over revs or misses a gear, or a poorly maintained motor, or weather...you get the point.

Stop the fear mongering and regurgitation of jalopnik gossip...

 

I couldn't agree more . The high compression with inconsistent fuel is the iffy part here . If one wants to push things then hey go for it , it's your engine and wallet .

 

Fuel is the main variable, but it's also what the owner of the car is comfortable with. I've had customers with K series vehicles state they want 500+ on pump, don't care if it's iffy, just want it to last more than a week... and it's quite possible to do 530-550 with the right turbo and kit on a K series.. and they will last years before finally throwing a rod. Again, customer's call -- you do your best to explain the limitations and consequences then do your best to satisfy their needs. A stock F letting go on the dyno is either negligence or a tired motor... I don't know the tuner in question so I'm not going to make any judgement calls.

That said, I don't get how our car handled ~470 on 92 with an OEM motor if past 400 on 93 is scary... heh. Our 92 is not "that" good (most K series on our 92 peak out around 430). Must of been a miracle motor, or the turbo setup was pretty efficient -- that's a pretty big variable too (not all "tubular" manifolds are that good). You guys must be used to seeing some junk kits if 400ish is your safe mark on this motor... 450-500 on 93 octane is not that "scary". Well, good 93 octane... I've seen 94 octane that's worse than 91 octane... lol

 

And now everyone knows who to call for tuning!

 

No not race gas, but they are likely running E85 or using a meth a injection kit w/91-93 octane. Definitely if they are over the 500 mark like the OP mentioned he was when the motor went...