Custom Tuning
 

How are custom tunes done?

I have a bud who's done these type of things and he's saying he can custom tune my BRZ without dyno'ing it, he said as long he can full throttle into 3rd gear, it's fine. T/F ? I was under the impression you needed to dyno it.

What are the differences between a custom vs stage 1 ?

It's what I'm doing at the moment. I just call it street tuning instead. As long as you can find a decent quality flat road that is minimal to no traffic, no cops, and long enough that you can do a 3rd or 4th gear pull to redline-ish. Preferable an industrial area on the weekends when there's no one working and little to traffic or empty highway if you can find one at a suitable time.

A dyno is just a more safe, closed, and controlled environment for a price. Whereas on the street, road conditions may not be perfect (bumpy roads, sloped roads, temp variations, etc) so you are taking a bit more risk and it's less controlled. You may get busted by a cop during a pull, annoying locals can snitch on you if they think you're street racing, driving them crazy with a loud exhaust, or think you're acting dangerously on public roads. Or you get in an accident if you lose control or something unexpected happens.

Stage 1 and stage 2 are more marketing terms IMO but typically an off-the-shelf tune suited for a stock car or a certain set of upgrades (intake and catback exhaust, headers). A custom tune is tailored to your car according to how your engine behaves and the aftermarket parts that you have. Since no engine performs the exact same way, variations in gas, and every aftermarket part performs different.

I have the OFT stage 1 tune with a perrin air filter, trd catback and jdl uel catted headers so I'm refining the OTS tune so it's suited to my car specifically.

Okay, was just curious.

How much better is a custom tune verus a stage 1? I use 91 gas and an invidia n1 exhast, thats about it.

How much extra hp/torque?
@G-awesome

Considering you only have a catback, I think the power difference between using an OTS stage 1 compared to a custom tune should be very minor. The tune will unlock the most potential from the engine and reduce knock on the OEM tune. A catback only nets about 2-3 whp. But if your buddy is willing to tune for free or for beer, by all means you can go for a custom tune! :cheers:

The difference is drive-ability
 

As a fellow AT owner, I know how horribly crippled the OEM AT is compared to the MT. An AT is geared much taller, and the engine has to work harder to accelerate. The toughest thing to do is tune for shift-ability. Shifting manually is more prone to lag, or whiplash, after a shift, and it takes a spot-on tune to prevent that. Specifically, the PI/DI tables have to be DI only in the rpm range after the shift, and PI and DI in the rev before the shift. A custom tune can make your car much easier to drive in traffic, if it's done right.

You mean much like the OEM tune then....

I would like to respectful disagree about street tuning..
"Street tuning" is usually setting up for WOT only, chassis dyno tuning usually involves a three dimensional tuning chart. Throttle position, RPM, and load: and needs a lot of time to get it right. That is why using a tune from a reputable source is often a better deal.
Experience with this particular engine is also a great benefit and time saver. With eight injectors tuning for dally driving and spirited driving is a challenge.

When I drive, I have trouble accelerating, I change it to manual mode and see it on 6th gear and im like wtf?

Alright, I just stage 91 tuned my car.

After I tuned it , my check engine light was lit up on my dashboard. Whats the issue here and is it dangerous to drive around with it? I have to drive my car for a few hours straight tomorrow, dont wanna die.

Secondly, I seem to have "knocking" when I break. As I come to a stop, the breaks knock back and forth. Dangerous? Whats the issue here and how can I get rid of this?

If you have oft read the code
if it says no codes it not engine code

It likely a P0700 if your auto , oft may not cleat it

if you want to clear it just diconnect battery and press brake pedal then reconnect battery, unless yo have obd scanner to clear codes.

no idea what the knocking sound is

Dyno's are great and convienent and you can set up what ever load conditions you like in a controlled enviroment.

however a good custom or dyno tune will be checked on street and track conditions as well

you dont have to "street" tune at WOT and whatever ecu logging you can do on dyno you can do on street or track. often you find things you need to tweak while driving on the street and track as its hard to simulate those conditions on dyno.

most tunes even canned or ots tunes are initially developed on dyno.

If you developing a tune from scratch yep dyno is the way to go.

If you already have a dyno developed OTS or canned tune thats done well and matches your modifications on a non boosted car then custom dyno tuning does not generally gain you much at all, and you would go pretty close just "street/track" tuning your good OTS/canned tune.

I have an auto.

As Im braking, I feel a small shift forward and backwards. Any idea what that could be? it feels like my brakes release for a split millisecond and then catch again

@steve99

yeah you will often get a cel code after flash with auto's as the comms to the auto trans ecu get turned off during engine ecu flash, the trans ecu get lonely and spits a code. sometimes it will go away after a couple of drive cycles if not do the battery reset.

When you flash/reset ecu some learned parameters are cleared this may make the engine run a bit strange for the first couple of drive cycles.

the "knock" sound is sometimes the ecu shutting off injectors on overunn ie coasting to a stop to save fuel, you sometimes get a bit of backlash is drive train creates a few weird sounds, usually more noticable with air-conditioner load or switching (ac runs with defrost function as well)


Table below shows the rpm the institutors start fueling again on overun, when car warmed up this occurrs at about 1300-1400 rpm, if you get a rattle arround then comming to a stop that might be it

like steve said, it's most likely the p0700 cel code. It has sometime to do with the transmission ecu not recognizing the new tune so it goes into limp mode as a precautionary measure. It happens all the time when you flash to an ots tune. It'll go away after you start the car around 3 to 4 times so it's a bit annoying. Or you can just clear it with the open flash tablet.

I'm not too sure about this 'knocking' you feel in the brakes. Sounds like it's just the abs kicking in when you brake hard so the brakes won't lock up.