Hey guys,

About to get my first tune in a couple of days. I have my 04 coupe overseas so you don't see many or any at all over here. Luckily there is an uprev tuning shop about an hour away. Just wondering if I should bring my car there with 93 octane or not? I can't get 93 so easily so 91 is what I would usually use. Also, what gear does it need to be tuned in? I've heard most cars are tuned in 4th, but my 04 coupe is 1:1 gear ratio in 5th. Thanks for the help.

 

if you dont have good quality gas your car will ping, they had to put in higher octane when i got my tune and i only put in 93, and they also told me to never get gas form stations right off the highway and after it rains. i also only go to stations with three nozels so you dont get the rest of somones 87 octane thats left in the hose.

 

use the octane that you usually use, if the tuned is for 93 but you dont use it that often, it could mess up the timing. I was tuned at 3rd in Intec Racing, WA

 

i was tuned in 4th.

 

I talked to a friend that was out of town for a while about my issue. He used to work on cars in his previous job. He agreed with using the gas that I usually use. I can't get the 93-94 octane stuff very often so it looks like 91 makes more sense since that is what I use. Now that is settled. What about the gear ratio issue? I know for my 04 coupe the 1:1 ratio is in 5th gear. Mikhaelbt and Shane, why did the shop tune your G's in 3 or 4th? Do you have different models with different gear ratios? Should I be tuning in one of the gears when I take my car in? Thanks for the help.

Tony

 

Tony, if you normally use 91 Octane that's what you should get tuned in. With my Osiris tune he nailed it to redline in the first 4 gears, that's when I left since I hate hearing SLICK scream....
Gary

 

^ I never got used to that either.

From my limited understanding it would seem to me that if you get your tune done to 93 and then only ever use 91 you'll be at risk of having over aggressive timing. We all know higher octane increases the resilience of fuel to detonation... So if the tuner is more aggressive with 93 fuel and you switch over to 91 I think you're looking for trouble.

 

^ I never got used to that either.

From my limited understanding it would seem to me that if you get your tune done to 93 and then only ever use 91 you'll be at risk of having over aggressive timing. We all know higher octane increases the resilience of fuel to detonation... So if the tuner is more aggressive with 93 fuel and you switch over to 91 I think you're looking for trouble.

 

I'm sorry but what? No gas from off the road gas stations and no gas after it rains? I get the 3 nozel thing, but the other 2 are just weird to me.

 

First, it depends on what you will be using to get tuned. If you are using the Osiris, you can have multiple maps for almost any reason you want, including different maps for different types of fuel.

If you can only have one tuned map, tune it for however you will be driving the car. If you are going to be using it as a daily driver running 91, then tune it on 91. Tune for 93 if you will be shipping your car back and will be running 93 octane. If your will be only using it at the track on 100 octane, then tune it for 100 octane. Just keep in mind that you'll need the gas in the tank while it's being tuned.

The entire point of getting tuned to have a custom map is to improve efficiency of your car, and whichever gas you are running matters. While you won't want to run a lower octane than you are tuned for, running a higher octane than you are tuned for means you won't be using the gas as efficiently to make power. Now, I'm not saying you won't see any benefits running a higher octane after you get tuned for say 91, but you'll see better gains all around if you have a map for it.

 

Definitely bring it to the tuner with the gas that you can normally get.

As for which gear he does pulls in, it should be done in the gear that's 1:1. However, the 5th gear 1:1 ratio pulls the G/Z up to pretty high speeds. The tuner may consider this too dangerous on the dyno. I know that we did 4th gear pulls in my E36 M3 for this reason even though 5th is 1:1.

 

Definitely bring it to the tuner with the gas that you can normally get.

As for which gear he does pulls in, it should be done in the gear that's 1:1. However, the 5th gear 1:1 ratio pulls the G/Z up to pretty high speeds. The tuner may consider this too dangerous on the dyno. I know that we did 4th gear pulls in my E36 M3 for this reason even though 5th is 1:1.

 

Thanks for all the replies.

I filled up with 90 Octane today. Thought it was 91, but i guess its 90. The tuner is an authorized Uprev tuner and he did mention that I can have multiple maps. So I'm going to look into that when I see him tomorrow. I'm really new to this tuning thing, so gear ratio is new to me as well. I just want to make sure that he does it in the proper gear if it needs to be 1 to 1. That being said, I never thought about the speed issue in the G. I've driven my G at top speed 15-20 mins straight at times during routine daily driving, and 5th gear is the gear that all get all my speed from. If its dangerous maybe 4th is better for that reason. Is there a negative to tuning in a lower gear like 3rd or 4th? It just seems like your results would be inaccurate. I've never dyno'ed my completely stock G, but thanks to members here I'm able to find those numbers. I'm going to use those numbers with what my results are tomorrow so hopefully they are decent. If a stock 04 coupe is around 225-235 hp at the wheels, then with a plenum spacer, rev-up airbox, z-tube, 4lb lighter flywheel, would 240hp at the wheels be realistic? Thanks again.

Tony

 

I wouldn't worry about how high the numbers are exactly, some dynos read high and will say your G make 225 hp, while others will read a bit lower and say that same G makes 210. While the higher numbers sound better, you will actually get a better tune on a lower reading dyno, but realistically, none of that truly matters.

What you should look out for is the base dyno (first dyno run before tuning) and the gains afterwards. The gains up top that says you made 15 hp, etc... mean nothing as you want as much gains as possible all across the board, so that's what you want to look for.

As for which gear to be tuned in, most tuners will use third because it's your strongest and tallest gear, but 4th works just as well. Ideally, you want to be tuned in at least third and whichever gear you spend more time in. It really just depends on the guy tuning your car.