Quote:
Originally Posted by northern2020
Sorry to derail the thread...
How do you like the Downpipes, and did you install them after the Akra or at the same time?
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I installed the downpipes about a month after I installed the Akrapovic exhaust, and installed the software about a month before I installed the exhaust.
I felt the biggest performance impact from the downpipes and downpipe reflash.
ESS 91 octane software only: The truck felt much stronger off the line and in the mid-rpm range. The upper rpm range felt similar to stock. The shifts were also slightly better. Spending roughly 2k is worth it.
ESS 91 octane Software + Akrapovic exhaust: The truck felt exactly the same, no noticeable improvement in performance. The cold start was slightly louder, and while driving, the truck had a slightly louder sound though it’s almost indistinguishable from inside. The shifts did have a slightly better pop, and the truck did feel slightly more nimble from the decent weight reduction. Personally I wouldn't pay 6k for this exhaust and expect a noticeable performance impact or significant change in sound (from inside the truck). If you look at the stock exhaust you’ll understand why its not much of a restriction.
ESS 91octane downpipe software + Akrapovic exhaust + SS downpipes: The truck felt MUCH stronger and MUCH louder. The difference is stunning. The entire rpm range feels significantly stronger and the response after shifting seems much quicker, probably due to the decrease in backpressure. On cold start the truck is VERY loud. So loud that it will sound as if a race car started (and this is coming from someone who drag races 1200hp turbocharged cars). Spending 2k on downpipes is stupid, though the difference (with software) is great. A cost effective solution is only doing software and catless downpipes, though some said the exhaust sounds strange. Depending on what downpipes you get, I bet you can do software and downpipes for under 3k. Much better than the 10k setup I have, and will have similar performance to what I got, and while retaining the stock look.
In normal mode and under normal throttle conditions the truck is louder than stock and emits a faint turbo whistle in the lower rpms. On occasion I do get some slight turbo surging (typically from heat soak after being in traffic) and mild on/off throttle hesitation, typical on factory turbo cars with similar mods. Only under full throttle (when the exhaust valves open) does the truck get very loud. Also the manual shifting in normal mode feels very sluggish and actually makes a louder and longer burble sound when shifting.
In sport mode (exhaust valves always open) the truck feels very responsive and the shifting is crisp. Manual mode feels great and has a great quick pop sound. You'll also notice a stronger smell of gas/exhaust fumes in this mode as a result of the outer exhaust tips bypassing the muffler.
In M-mode (all vehicle settings set to max performance): the truck feels great. Very responsive, quick shifts, great exhaust notes, VERY loud, and very twitchy in traffic.
General Downsides:
- You will get a strong smell of gas/exhaust fumes while driving in traffic, sitting at stop lights or during cold start or after a quick pull through the gears. I've actually had a few people pull next to me and complain while in traffic (though it’s the SF Bay Area, CA so I'm surprised).
- From time to time I do get traces of detonation during partial throttle in lower rpms (exhaust is too loud to hear it in the upper rpm range).
- On a few occasions I've noticed the truck emit plumes of white smoke (smells like oil) during normal acceleration/shifting after slowing down in the highway. No idea why this happens or why it rarely happens and it’s not repeatable.
- I did have one engine malfunction error after hitting the rpm limiter in first gear under full throttle. After restarting the error went away and I've never had it happen in the past 5,000 miles).
- I had the error described in this thread, however I've been unable to neither replicate it, nor do I know the cause. Unfortunately I'll need to remove the downpipes and reflash back to stock (leaving the exhaust) to avoid dealership issues.
- The downpipe install is not fun. I did it myself (very experienced and have the correct tools) which took 2.5hrs. A normal user would have great difficulty doing this. Most shops would charge a ~5-8hrs for this job (350-1000 in labor depending on the rate)