Last year I did the Delicious Stage 2 Tune and I had been meticulous about doing the before and after dyno numbers. Well the results were disappointing to say the least. Lost more than 46HP (that's slightly more than a 10% loss) and 24 TQ loss. Consulted with Delicious and they suggested it was probably low quality fuel. Tech at Dyno test-site first instinct was low quality seasonal winter fuel but he figured there is no way it should have lost that much. The Tech ran several dyno runs and he picked up plenty of pinging, he suspected too much advanced timing which was causing knock situation.

Waited it out into the summer season to see how things go, there was still no improvement. Reverted back to stock and voila the car woke up in a big way. Noticeable low end torque was back and loads of power back at the 6000 RPM mark, exact areas where the dyno showed power losses.

Takeaways, placebo effect is real and don't put your money on your butt dyno. The car was definitely accelerating very differently with the tune you get the sensation of rapid acceleration and the dyno graphs shows areas of far steeper climb in the HP and TQ curve but at less power!

Rayspc3 in his youtube channel did a review on the Delicious Tune stage 2 last year and I must say he was spot on when he remarked the RCF seemed to be pulling timing. He just didn't have the numbers to prove it. He has ARH Long system headers as I do. Delicious did offer a custom dyno tune since the original tune is based off PPE setup but after mulling it over the cost-benefit was not worth it for me. I'm pretty happy with the car as it is without the tune.

Another strange thing happened which I'm not sure if it correlates with the tune but a few days after the tune my fuel pump started buzzing, even after reverting to stock mapping fuel pump still buzzes. Keep in mind when you revert back to stock its a file you receive from delicious. I'm not sure if the test car they used to develop the tune didn't have the most up to date ECM program Lexus released that resolved the low fuel pressure pump buzz or my pump is showing signs of going bad. If anyone out there has the most recent updated ECM program file saved somewhere drop me a PM that would be greatly appreciated. Hopefully that would resolve the buzzing.

Dyno graph below yellow curve is after the Delicious stage 2 tune, notice how the torque starts at a lower range but ramps up steeply which explains the sensation of rapid acceleration on the road. TQ then bobs up and down in the mid-range instead of staying nice and smooth as it was with factory original mapping.
The HP graph most dramatic change is at 6000 rpm mark with huge loss of HP. The ECM appears to pull timing due to increase knock at the heavy engine load.


Yellow graph result after Stage 2 Delicious Tune

 

Sorry to hear that.. Hope it can all work out for you. I think you should try RR racing as it is the only proven tune with consistent gains across the whole rev range.

 

Thanks for the deep dive and the background of what you checked before immediately blaming the tune. I'm working on a tune for mine (using VF Tuner) and had a quick question on the dyno setup: did you dyno right after flashing or did you drive around for a bit? Basically I'm wondering if I can flash a few different revisions on the dyno or if that would end up being mis-leading due to the ECU "learning" that happens.

As far as the fuel pump buzzing, VF Tuner (which is what Delicious is using btw) should be at one of the current baselines that has that fix incorporated. Your ECU ID should show up as 24283 or 24284. What I'm unclear about is if the VF stock files are a full upgrade, or just a change in the specific map files. Was your car upgraded by Lexus before the tune, or did you use the flash to upgrade your ECU? If you the car has not been previously upgraded by Lexus, you may need a trip to the dealership for an ECU flash (there's a TSB for it). The stock files I have are probably the same as what was provided by Delicious.

 

If i remember correctly after the first flash it reset back to 15 kclv, but revisions to the same file didn’t reset my kclv. During dyno pulls, I switched to OBD Fusion app for logging and to see what the knock feedback was doing and to see if kclv was rising or lowering. Just a heads up, dont try out that example file that they have in there, it plummeted my kclv down to 10-13 from 19/20 in just one pull

 

Thanks and no worries. It's great to have a community such as this one where we are able to share our experiences and learn from one another.

Thanks for your response. I did drive the car for 2 weeks, I would say I put a minimum 400 miles on tune before running dyno numbers. Enough time for the car's computer to complete the learning under various engine loads.

I already had the upgrade by Lexus to correct for low pressure fuel pump buzzing prior to the tune. I recently took it to a Lexus dealer after removing tune and returning to factory settings to check out the new buzzing and they stated the car has the latest software. I'm not sure if they are basing that out of work record they have on file or actual reading of my vehicle's ECM. I visited the Lexus dealership twice and they failed to locate the sound. It seems like they are so unfamiliar with RCF's they don't know what to look for. They finally told me unless I remove all the mods on my car they will not proceed with further investigation. Yesterday after I picked the car from the dealer I popped my head in the back seat and could clearly hear the buzzing coming from underneath the cushion seat on the side where the fuel tank is located. I'm certain its the fuel pump. When time permits I will pull the back seat cushion off and closer examine source of sound.