Tuning question?

[Dan03mach]

I was wondering has anyone ever tuned a car by putting a load on it using the trans brake? Well I cant get on the dyno right now and going WOT on the street in high gear to get full load on the car is pretty dangerous. So I used the trans brake to put a load on the motor so I could tune the car through the maf counts of the RPM band I can get on the trans brake. The load counts were 1.803 at peak so it was damn near fully loaded up but I could only go to 5.7k rpms on the brake. When I first started with the tune today it took about 4 seconds to fully spool the turbo after foot braking it and then putting it on the trans brake and the A/F was pretty fat. Now after I got finished working with the tune, it now only takes about 2 seconds to fully spool the turbo after foot braking according to my data logs and my A/F is pretty much right were it needs to be. I'm just doing this to get the tune pretty good before I put it on the dyno and turn the boost up. I didn't know if this was a good idea or not but it seems to be working out for what I'm doing.

[Dan03mach]

I just made another adjustment and got the spool time down to 1.75 seconds and got the load to 1.999 fully loaded...

[TEAMJACOB]

I don't have anything valuable to add but picturing your car in wot flying down the street puts a smile on my face assuming of course nothing bad happened. Just a balls out car flying by while some poor schmucks are sitting at starbucks or something along those lines.

[bcar]

Don't know if it is a good way but watch your tranny temps, the transbrake will heat it up fast.

[Dan03mach]

Don't know if it is a good way but watch your tranny temps, the transbrake will heat it up fast.

yeah I have a gauge on it. I was keeping it around 160-170 degrees...

[greenbullitt]

no, the transbrake does not provide as much load. put it on the rollers for the closed environment you need. That 10.0 shits gonna cost you a piston, glad youre working on it

[Dan03mach]

no, the transbrake does not provide as much load. put it on the rollers for the closed environment you need. That 10.0 shits gonna cost you a piston, glad youre working on it

Yeah I know that 10.0 is way to fat. I leaned it out a lot and it should be where it needs to be. On my data logs it was showing full load so I don't know... I'm sure it will need to be tweaked once on the dyno but for now it is pretty close. The T-brake was the only way I could put a load on it in the driveway. I'm sure the neighbores are loving me now. lol

[Beenfetchedlately]

A Dyno will never provide true load of a 3200 lb car with a 2000 lb roller. Stick to a different gear like second and highway bombs on a long open road or the track.

[Dan03mach]

A Dyno will never provide true load of a 3200 lb car with a 2000 lb roller. Stick to a different gear like second and highway bombs on a long open road or the track.

That would work if I can find a place that is wide open. I guess I need to hook up my wideband to my data logger...

[majorownage]

derp

[turbos66coupe]

Just out of curiosity aren't you running e85. I thought a good af for e85 was somewhere near 9:1 or does your wideband scale it differently. I don't have much experience tuning e85 so just wondering.

[Dan03mach]

Just out of curiosity aren't you running e85. I thought a good af for e85 was somewhere near 9:1 or does your wideband scale it differently. I don't have much experience tuning e85 so just wondering.

My wideband is setup to mesure gas. So it reads a gas scale... It's all the same.

[turbostang]

You've gotta be careful to what/how your doing it Dan. The transbrake and coming up on it is a completely seperate part of the tune, and is VERY important, but not a likely place to hurt anything - for the most part, you can be rough on it, with lots of timing and higher than normal AFR's if that's what it takes to bring it up on boost... just be careful that your tune is spot on once you let go of the button.

Not sure what your tuning table looks like, but your VE typically would follow a completely different path on the brake vs when you let go of the button, so it kinda keeps you out of trouble on it's own.

As Mike said above, the dyno should just be a guideline and the lightweight roller should be treated as something to get you close. I usually shoot for about 1/2 point richer than you'd run it - because when it's on the road, it's gonna lean out some. You don't want to let that get taken care of in the hands of close loop correction. You'd (I sure would) rather have the tune close as possible and rule out as much correction as possible. As in, tune it in open loop to your target AFR and get real close, THEN turn on closed loop to bring the 02 sensor into the picture for feedback.

[JETFAST]

load is load. only way it is going to change is by the other axis ie rpm, kpa, ect.