Dyno shop feeding me crap?

[tacocharger04]

I got my fuel mods and piggybacks hooked up about 2.5-3 months ago, then a week or so later I stoped by my local dyno shop (CTR dynosports,Honda & Acura specialists) to get 'er tuned up. I have read gadget's U-tune guide, but I think that it leans more in the direction of the older yotas with the 02 sensor and not the air/fuel ratio sensor for tuning closed loop by means of the road tune. Every thread that I have found on the subject before hand says not to waste your money on a dyno tune before you do a street tune. The shop that I went to said that there is no need for a street tune because the AFR calibrator is preset and that is what controlls the closed loop so all that i need to do is tune the open loop on the dyno, So I said fine and had them tune it on the dyno first. The guys at the shop said that I dont need to have a bung installed or the first 02 sensor removed for tuning because they have one of the best sniffers on the market and it gives a very accurate reading. So we tuned it on the dyno with the sniffer in my tail pipe and got the AFRs to I think 12.9 and it put out about 220 rwhp. My question is were these guys feeding me shit just to get the $100 per hour rate on the dyno or are they in the right? Its not like I was'nt going to pay them for the street tune. And do you think that I got a accurate reading from the sniffer in the tail pipe? The truck runs strong on one run I even got about 285 foot pounds, but that number was a fast spike before the torque converter kicked in for the shift. All the info about my truck is on my signature below. As always I appericeate the help and the shared knowledge.

[drabnor]

you need to road tune it, both the ftc and the a/f cal. and yes you need a wideband bung/sensor, your cat(s) fuck with the reading the sniffer gets

[tacocharger04]

My Instinct told me what you just stated, but i figured what the hell these guys are perty cool and they have a couple of drag cars that they race and tune all the time so they might just know what they are talking about, but now I am having second gusses. And I only have the 1 OBD 1 cat if that makes a difference.

[tacocharger04]

Another question that I had is does my ECU still maintain its addaptive (learning) properties with the piggybacks?

[drabnor]

Originally Posted by tacocharger04

Another question that I had is does my ECU still maintain its addaptive (learning) properties with the piggybacks?

yes

[tacocharger04]

That is what I was think'n also. So if I get it tuned in the best that it can be, then drive it arround for, say 500 miles or so will I see an increase in numbers at the rear wheels or just better driveabillity? Mabe both?

[Gadget]

It sounds like your truck was not tuned properly.

To do it right you start tuning with the fully warmed up in neutral. You read the scan tool and see what the fuel trims are and adjust the fuel map as needed to cancel out the fuel trims as needed. Then you start slowly driving and keep tuning closed loop canceling fuel trims as needed. This process continues until you have enough throttle for the ECU to switch into open loop.

What the URD AFR Sensor Calibrator does is alter what the ECU thinks is 14.7:1 AFR. It is used to make richer mixtures appear to be 14.7:1 so you can richen the mix in boost while the ECU is still in closed loop mode.

What will happen when you use the AFR Sensor Calibrator to richen the mix is the fuel trims become very positive. The initial setup of the AFR Calibrator you use a wideband display unit to read the mix and alter the map setting in the AFR Sensor Calibrator to get the mix where you want it.

Once you have the mixture set, you go back and retune your MAF Sensor Calibrator to to drive those positive fuel trims caused by the AFR Sensor Calibrator back to ZERO. This will result in a very responsive boosted engine.

Before you can properly tune WOT you must tune the entire closed loop portion of the map. If you do not the "adaptive" control of the ECU will screw your tune up. No matter what some dyno shop tells you on these trucks changes in the closed loop fuel trims has an affect on WOT fuel mixture. You need to stop the ECU from doing all this adapting and the way you do this is proper closed loop tuning by cancelling fuel trims. Once you have them canclled out there will not be much change in the trims and as a result there will be very little change overall to the WOT mixture. It will still vary a little bit from induction air temp changes from the weather, but no where near as much as if you did not properly tune closed loop.

I hate to say it, but from my experience most of these dyno shops will give you a crap tune because they think they are smarter the all of us here. Most have no concept of closed loop tuning and either don't understand it or do not want to take the time to do it and will try to convince you it is not needed "the ECU takes care of it."

I have seen so many tunes butchered by dyno shops that I simply do not recommend you have your truck tuned by a so called professional. If you want it done right do it yourself by following the U-Tune guide.

Once you have closed loop dialed in, then tune open loop. If you have a heavy truck like a 4x4 they seem to really like being in the 11.0:1 AFR range. If you have a small light truck like a 2x4 SRunner, and want that last 3-4 HP, then lean it down to 12.0:1 AFR.

Don't let some goof that has a dyno try to convince you it will make more power at 13.2:1 AFR. It might, but for how long?? It is nuts to run a boosted engine that lean.

Now if you really thing you must have your truck dyno tuned read and reread the section in the U-Tune guide on how to correctly do that. Pay paticular attension to the part about YOU MUST FOLLOW UP A DYNO TUNE WITH A ROAD TUNE. The WOT AFR on the dyno will in most cases be very different then it will be on the road after you leave the dyno.

Most dyno tuners are good at tuning stand alone EMS, but don't have a clue how to properly tune a piggy back so keep that in mind.

[VF'N8]

Gadget, I have the Esc function, which, like the AFR Calibrator, allows you to adjust the fuel ratio as you please in all boosted regions, does the part above about the positive fuel trims needing readjustment in the portion of the map that the AFR Calibrator is acitve apply to the E for the older trucks with 02 sensors. In other words does the post of yours above apply for FTC-E as well.?

[Gadget]

No not really.

For the ESC1 function, ignore the postive fuel trims. When that device activates the fuel trims will roll very postive and you have to let them. Do not cancel those positive fuel trims, IGNORE them.

At the activation point tune only with the wideband. If your WOT Open Loop target AFR is say 11.0:1 let the area controled by the ESC1 to be at least that rich or even richer. The control is not a precise and there will be a variation in the AFR from time to time and it is better to be richer then needed then to lean.

[tacocharger04]

Gadget, does anyone at your southern California hub tune trucks that are brought in or is that just your warehouse? Its not too bad of a drive for me comming from centeral Cali. The reason being, I dont have a laptop or a friend that has one, no tuning tools, and I have called at least 4 shops in my neck of the woods and none of them sound very inthusiastic about riding along for a road tune. To be honest not one of the shops that I have called have even ever worked on a s/c taco, Iam tired of these local "professionals" learning on my truck I need to find someone who has done this before.