3500 Engine - what is the best octane fuel to run?

[Starglow]

Hi,

I have a 1999 Pontiac Grand Am and recently completed doing the 3500 engine swap as follows:

2006 G6 LX9 38k
28# Trailblazer fuel injectors
TCE 65mm TB
CAI with K&N filter
MMS PCM Tune
JEGS coil pack
Taylor wires
NGK 5599 spark plugs

I've been running mostly 87 octane fuel, but the car does seem to have a bit more zip with higher 93 octane fuel...note that the higher octane fuel was added to about 1/2 tank of 87 octane, so it was really a 50/50 mix.

What do you guys recommend would be the best octane fuel to run with this setup?

Thanks...!

[young gun]

If you are not tuned to run 93 it won't produce more power. What it will do is reduce any KR you may have which you may be experiencing a "bit more zip"

Being a fairly stock engine you won't get much out of running 93 tuned. so just stick with 87

[pocket-rocket]

If you are not tuned to run 93 it won't produce more power. What it will do is reduce any KR you may have which you may be experiencing a "bit more zip"

Being a fairly stock engine you won't get much out of running 93 tuned. so just stick with 87

^^^This.

From what I remember about being told about the stock GA tunes is they run a lot of spark advance to the point of the PCM pulling spark from the factory so I think young gun is spot on.

Sent from my HTC One X using Tapatalk 2

[young gun]

Also if you decide to get a real tune and not a canned one (which I highly recommend) You want to get a wideband o2 hooked up to get it as good as that tuner can get it.

I got a tune from a local guy after milzy swapped it and it is a million times better. Honestly felt like a new car after it got properly tuned. I haven't had a chance to go back to the track to see the improvements but I swear it is at least .2 faster in the 1/4. I was hitting 14 degrees of knock so I may have had that kind of improvement.

[Starglow]

Thanks guys. Yeah...I wish I could get a local tune done. There's a few local shops that tune the ricer cars, but it's hard to find someone who knows these GM cars well and how to properly tune them.

[young gun]

Thanks guys. Yeah...I wish I could get a local tune done. There's a few local shops that tune the ricer cars, but it's hard to find someone who knows these GM cars well and how to properly tune them.

I don't know squat about them but I doubt they can be that bad.. http://www.carolinaautomasters.com/gmtuning.php

Can call these guys.. http://www.tickperformance.com/

These guys.. http://www.mayhemmotorsports.net/

The gentlemen that did my car was into 3800's but he did great on mine. The thing to look for us would be just a GM tuner that is willing to tackle ours. Or someone who does 3800 as flashing and what not is very similar. Excuse the lack of knowledge as well I have a lack of knowledge for tuning :P. I just know tuning is very important and can make a huge difference in a car.

[Starglow]

The guys at Mayhem do a lot of Corvette and Camaro tuning and they're close to me so I'll stop by and talk to them this week. My son and I both agree the car tuning needs more work.

Thanks for the links.

[Superdave]

I ran 89 octane E-10 in mine except for at the track, then I ran 91 or 93 because it's pure gas around here.