royal flush

on a dyno or ar rhe drag strip?

Andrew

If mods need it and tuned for it, yes. If not, may slow you down. Just use what the manual calls for if stock. If not, use what was in the car when tuned.

royal flush

Thx for reply--only mod is Vaeaeam intake----Im just asking if anyone has seen a diff.. on a dyno or drag racing--

Andrew

With just just that mod, no, no difference. Octane does not add power, it is only a antiknock agent. It allows the tune to be more aggressive. Too many variables to give you a clear answer. From what I have seen, stock LS1, no difference. If tuned without mods such as cam, higher compression, etc, then no significant difference. However, if cammed and higher compression or FI, yes, higher octane does make a difference.

tstad9i1

LS1/FI tuned on 93, drove from GA to CA. Very noticeable difference hitting NM where where all I could get was 91. No more boost runs after hearing all that pinging in or out of boost. Could have just turned up the Alky but that wouldn't help with the sluggish running even just around town. Using boostane now, can't convince myself to pay all that money to tune/dyno for 91 when it spends most of the time in the garage nowadays.

Andrew

Yep, if FI and tuned on 93, bet you dropped some serious power and lots of pinging if wot.

leadfoot4

Let me toss this in the mix....stock C-5, 6 speed, OE tune, 93 octane w/10% ethanol VS. 90 octane 0% ethanol......

Jackie N

The 93 e10 is probably the exact same fuel as the 90 ethanol-free. The octane bump is achieved with the ethanol, at a cost of 3-5% less available energy.

Nobody is gonna be able to answer your question reliably, and again the more important factors are ambient air temps, gas quality, and altitude.

Im of the opinion that a decent 90 octane in a stock C5 won't have actual detonation issues. With that said, factory (especially a 20 year old one) knock sensors are hardly a reliable way to detect real detonation so who the hell knows when the ECU might unnecessarily retard timing.

You'd have to test for yourself. Except you'd be testing on different days, at different temperatures and humidities, and possibly with different readings from the knock sensor ..... So you still won't have a clue!

The reliable testing would be on the dyno, with a wideband o2 sensor and exhaust gas temperature probes in the headers. Yikes!

KnightDriveTV

I moved from Ga to NV. In GA I actually removed my supercharger after many years, returned NA (because I frankly just like the car better that way...doing a video on this on KnightDriveTV shortly) but...I retuned on 93 in Ga, for my N/A with bolt ons state. Now, here in NV, all I can get is 91 and yeah...it's definitely a difference and I'm really considering E85 frankly. My gas mileage has gone down a lot because my car is pulling timing. My gf's C6 has even had a stint of bad blow by and she was getting a bunch of knock (her car is basically a stock LS3 6spd!). There are low octane tables in the pcm, but inevitably there was a learning phase the car didn't like. She is getting 28mpg versus the 19.5mpg she got initially, (she commutes in her car 70 miles round trip, daily) so all is well, but my C5Z is still unhappy as hell. I have to definitely get into the timing and timing modifiers for when the car gets some heat in it. I ripped it the other day and heard a brief can of BB's outside I was holy F***. So yeah, getting the wideband in next week and going to see what I can do to make the best of it.