What constitutes a good tune?

[thomjs1]

We all hear that you need to have a good tune, but what does a good tune consist of?

I plan on installing a SSAFC soon, and want to do the tuning myself so I am looking for some knowledge on what I should be looking for.

 

[jeffmsp]

is it fuel or timing and fuel?

if it is just fuel you will want to try and modify the map so that you are running a safe afr for any given boost pressure you plan on running. A "safe" afr is determined by a number of things inlcuding but not limted to the type of gas you use, the temperature of air the is entering the engine and how much load is on the engine.

A safe bet would be to tune for 11:1 AFR on 91 octane while in boost and see how your setup likes it. If you have a decent intercooler or 94 gas then move towards 12.2:1 under boost.

if you are just using the afc then thats mostly what you will be doing. work off the base map and increase/decrease fuel values in the cells so that the afr stays as close to the target value under boost as you can. easiest way is to ride shotgun with a laptop and have someone else drive around for an hour or so while you make changes to the cells.

i cant remember offhand as it has been a few years since ive tuned a "stockish" setup, but I believe under ~4000rpm the stock ecu is still in open loop mode and will be running leaner than you think you should be, then there will be a noticeable switchover as the rpms increase. im sure someone here currently running an afc can give you more/correct info on this. it is a switchover point from open-close loop. might make tuning a bit confusing if you arent aware of it, i know it did for me back in the day on my first tune.

 

[thomjs1]

Thanks for the info!

I will just be tuning the fuel with the SSAFC. I have been thinking about going with the one that allows timing adjustment or the Unichip, but I know that I will definitely need a tune by w professional with those.

 

[DiscreetSpeed]

IMO - targeted afr's

aggressive 12-12.5
Conservative 11 -11.5

I use nothing less than 93 octane.

 

[Preferio]

Thanks for the info!

I will just be tuning the fuel with the SSAFC. I have been thinking about going with the one that allows timing adjustment or the Unichip, but I know that I will definitely need a tune by w professional with those.

Do not get a Unichip... A) You can't tune it yourself. B) I've worked on two MSPs that had a Unichip installed and was having drivability issues that no one could figure out... First thing I did was disconnect that ******, and voila! They ran fine.

 

[KrayzieFox]

And by aggressive, he really means brave. Stick to 11's if you want a safe daily driver, but if you're after every last bit of power go for 12's.. just keep in mind that a piggyback like the AFC won't be 100% consistent.

Must be nice to have 93 readily available, I can't get any better than 92 with 10% ethanol... and most gas stations only have 91 with EtOH :/

 

[Preferio]

I run low 12s on mine. There for a while I had a random spike to 13.1 that freaked me the **** out.

 

[KrayzieFox]

^I'm the same.. I tuned for 12's but would occasionally hit low-mid 13's under WOT so I retuned for mid-high 11's to be safe. I can't have my daily blowing up, as much as I enjoy performance I prefer reliability and peace of mind.

 

[Preferio]

^I'm the same.. I tuned for 12's but would occasionally hit low-mid 13's under WOT so I retuned for mid-high 11's to be safe. I can't have my daily blowing up, as much as I enjoy performance I prefer reliability and peace of mind.

I've done the same. I detuned it, sold my V1, and purchased a V2 so that I can datalog it and hopefully iron it out. I haven't installed the V2 yet, but that'll hopefully help me get rid of that "holy ******' s***" AFR. lol

 

[MSP2003.5_Nick]

Fuel tuning is easy. It's making an ignition map from scratch on a standalone that gets sketchy lol. Dyno is your friend