[QUOTE=QwkTrip;15108539]Truck has been inconsistent in the way it accelerates. LEC looked at a data log and advised me there is a boost leak somewhere. Too cold outside to deal with this now but I'll have to hunt it down. Still bone stock. Won't do parts swap until there is a nice day to do the work.[/QUOTE Because you say inconsistent, I would lean towards blow off valves, if it was plumbing, you would see an equal response all of the time, but if the blow off valves are sticking open on occasion it would feel a little funky. Mine too drives like this from time to time. I do not like all of the plastic plumbing on the boost side of the intake system, just looks cheap and like it might be trouble sooner than later.

 

Thanks.

 

Loaded the SCT 91 tune today just for fun. Frankly, I don't care for it one bit. Still running 100% stock truck otherwise.

The SCT tune drives nice in easy driving and readily drops in to the highest gear possible which is nice for cruising. However, that also means the trans has to shift every time you ask it to do something. Many times it will shift through 2 gears to get the job done. All that shifting equals slow response time and the feeling that you're abusing your truck. It does accelerate good but the engine has a sound like it is straining at full throttle. Combine that with multiple upshifts and it just feels like the truck is getting a work out.

The LET 91 tune on the other hand is silky smooth and the engine never feels like it is straining. Unlike the SCT 91 tune, the LET tune is in a constant state of readiness to respond. It does a better job keeping the turbos primed for use. The trans tends to hold a lower gear and does a lot less shifting at part throttle. Shifts happen quicker too. Not harder or faster, just quicker to make a decision. A downside is it won't easily drop to a high gear for cruising.

There is just too much drama with this SCT 91 tune at part throttle. Upshifts, downshifts and the jerking that goes with it, upsetting tires, sudden revs, grabbing too much attention. I don't like it. The LET tune is smooth and swift with no drama. It's the difference between an athlete that isn't even breathing hard after a 100 yard dash, versus a fat guy that can still run quick.

If you normally drive easy and all you want in a tune is some giddy up and go, then the SCT 87 tune works great for that. If you're going to bump up to a 91 tune then skip over the SCT 91 and get a custom tune. World of difference in part throttle performance.

 

I'm running the SCT 93 tune now, and what I don't like is that some of the shifts are like I like them (quick & firm), others feel like stock. I haven't had enough time to figure out which ones are which except that 1-2 is always nice & firm, but 2-3 is much more soft (longer shift duration). I may have to indulge in a LET tune, if ALL the shifts are short & firm. Can you confirm? I would however prefer that it not hold on to lower gears too long. I'm so used to my BTS 4R100 in my old F250 that I'm really sensitive to the shifting now.

 

No, the LET shifts are not firm. Most shifts go unnoticed. It does make decisions quick though.
If you want it more firm you just ask them. You're not just buying a tune, you're buying free changes for life.

MPT may be more your style if you like the harder shifts. But you pay for changes every time you ask.

 

Thanks for the heads up. I'm a huge believer in quick, firm shifts for tranny clutch life. Long, soft shifts eat clutch material unnecessarily. I'll get in contact with them and see what they can do.

 

It has taken 2 months but I FINALLY got to play with something to get a sense of comparison. I can tell you my big crew cab 4x4 157" wheelbase truck with a 210 pound topper is quicker than a Infiniti G35.

The G35 guy was a maniac fool that had no off button so if you talk to him he won both times. But truth is I wasn't going to keep feeding his bad behavior and let off early both times. From a stop I put him behind my rear bumper with the flick of the throttle. I could have put much more air between us if I wanted. It just seemed like it took him forever (in comparison) to get in a power band. Meanwhile my Ecoboost could just walk away at will.

The second time I ran an experiment. I let him get in power band and then made an attempt to pass using 2nd gear. We were evenly matched so I didn't keep going. I just wanted to test what would happen if I didn't have advantage of leaving from a stop in 1st gear. Although, that pass attempt resulted in him doing 100+ mph and I'm not sure when he stopped. Like I said, he was a maniac fool but that does remove all doubt he had it pinned to the floor!

So that pretty much confirms what I thought. There isn't a lot extra in the tune above 50 mph, but this truck moves like a sling shot from a stop.

 

I made a mistake. I don't know my Japanese car badges. It was an Infiniti G35.

I should have figured it out quicker because the story just doesn't make sense since Lexas drivers are even more boring than Toyota drivers.

 

A stock-ish G35 will run. Sedan or coupe? I'm guessing sedan.
I wouldn't downplay a couple Lexus models: IS-F and the new RC-F to name a couple. They look much like the other trims but they are monsters. Hard to find though.
Regardless I'm enjoying your feedback on the LET tunes. This might be on the somewhat short term wish list for me.

 

It was the 4 door.

 

Sedan got a slightly different, more tame, tune than the coupe. Likely an auto too. 6spd coupe would be have better.

Regardless, always fun to scare the pants off small car owners with a 6,000lb truck. Had a yuppy in a Cooper S try me the other day and he had to let off as I wasn't and we were coming to a two into one merge.

 

That tune is some of the best fun money I've spent in a while. I can enjoy it every day at real-world speeds. I've had cars that were a lot faster but I couldn't really open up the throttle until illegal speeds. This truck is just good clean fun without doing risky things.

I've had the ability this whole time to put my G-tech on it and get performance stats but I'm not going to because that's not what this is about. I'm just having some fun with it.

 

Good to know!
My '06 had 5 Star tunes on it, and it was enjoyable, but it's my understanding that the EB really comes alive with even a modest custom tune and some data logging.

 

Yes, take whatever power gain you got from a tune on your 5.4L and multiply by 3 or 4.

 

I have been looking at tunes as of late and have been reading up on SSI tunes. Supposedly the tuner has been labeled as a ecoboost tuning God. (supposedly not self proclaimed) They offer the choice of 4 different stages of tunes and three choices of trans shifting. They also have a tow tune. I have read nothing but good things especially the customer service from Shawn.