APR DTR8868 Stage 3 review.

[GoCougs1234]

2021 SQ5 Prestige with 75,00 miles already with APR 91 stage 1 and APR intercooler. I had a local turner install APR stage 3 on Friday (great shop, excellent reviews, great quality of work). I am thoroughly unimpressed with Audi's 2025 offerings (and the rumors of such) so decided to go 91 stage 3 to satiate that bug. Also, I want emissions compliance, no exhaust stink, and the entire install from the same vendor in order to minimize risk. Plus, I've had great success with APR thus far, esp. readily getting all my (many!) questions answered. Ergo, APR DTR8868. Since the install I've done ~150 miles and ~20 launches. I'll update this thread as things change and/or to answer questions. Special thanks to member SQ5onFIRE. Via DM we were trading info and such the last few days in order to fine tune our knowledge.

TL;DR - Seamless install, huge performance improvement, esp. from a roll, but the legs are long and launching is still tricky. I do mostly freeway driving and frequent road trips out in the middle of nowhere so this works perfectly for me.

ECU tune: As expected, the power band moves up quite a bit - like 1,500 rpm, which takes getting used to. The party doesn't start till 4000 rpm and to stay on the boil you have to keep above 4500 rpm. Zero exhaust stink. (Very) part throttle (say, 10-20%) around town driving feels the same - no hesitation or bogging or the like. Throttle response/mapping and exhaust crackles feel about same as stage 1. I've had one CEL (P015B - 02 sensor delayed response from lean to rich...) and one DTC (P227900 - intake air system leak). I've reset both and they haven't come back. I have a homemade (and VERY temporary) intake installed currently (removed the lower factory air box, installed a K&N filter, walled off the affair from the engine) - not sure if related. APR is set to release its B9/9.5 SQ5 intake very soon which I am waiting for. I also have an intermittent whistling noise (sounds exactly like a leaking window or door seal) unrelated to engine speed, boost level, drive train speed or vehicle speed, but instantly goes away when I step on the brakes (thinking vacuum leak - currently in the process of troubleshooting - something may have gotten knocked loose during install).

TCU tune: I had the 034 Motorsport trans insert installed at the same time and while my AMAX shifts feel normal, non-AMAX WOT 1-2 shift is 10x as harsh. Also, the down shifting in S when coming to a stop is sorta harsh too. I'm going to remove it as my hope is these two issues go away. Launch control is actually still tricky as with stage 1. Launch too soon and there is ZERO boost and hold boost too long and it feels like the ECU is cutting torque upon launch (TBH, I was under the impression that launch control had more fineness). Note my 60' time is notably slower than stage 1. With more practice I could probably match my stage 1 60' time and thereby shave a tenth or two off both 0-60 and 1/4 mile times, but my launch control counter is at ~300 and have never had an tranny problems/CELs/DTCs - I want to keep it that way! Besides, launch control isn't practical or useful in daily driving.

Look at that 40-100 roll performance: +25 car lengths vs. stock and +12 car lengths vs. stage 1:

[SQ5onFIRE]

It sounds like a potential vacuum leak. I have not experienced those sounds.

[fusion3214]

great post! been looking for some 91 octane data for stage 3 since we only have 92 in hawaii. will probably end up going the 810 route since i already have stage 2 hardware.

[GoCougs1234]

Welp, practiced launching a bit more. Upon initial brake torque, it takes a bit of time to rise to ~2,500 RPM, then the revs stay there for a bit, and then there's a second rise, and on this rise at about 2,900 RPM, I immediately release (DON'T wait here or you'll hit a major torque cut on launch), and that is where I had the best launches. Still tricky though, and TBH, and to echo my previous thoughts on the subject, I was expecting launch control to be a bit more refined/repeatable. Also, on the 1/2 shift, I'm either hitting a rev limiter or fuel cut. Either way, this was the best 1/4 mile. I had to let up at the end so that cost me a bit, so gonna say a solid 11.70 sec @ 116 mph performer. On a previous attempt I managed a 0-60 in 3.55 sec and a 60' of 1.71 sec but couldn't hold on for the 1/4 mile. That portends of a 11.60 sec performer. On the last attempt launch I didn't get AMAX shifts (I'm guessing tranny temp) so called it a night. Also, I added the IE intake and turbo inlet just prior to these runs, so that helped a bit, too.

All in all, quite pleased. After I swap out the tranny insert I'll post a full update (next week some time).

[SQ5onFIRE]

Nice runs! I’m not going to have that type of DA for a while unfortunately. What was your boost at around 2900? Felt like I tried that and it was no boost at launch. Felt more past that when it went closer to 3500 but again your 60 foot is better then mine so it must have worked. It is tricky to launch and if you watch ignition tube videos when he did his first launch on the pure 750 he commented about the same difficulties. I think it will just take practice.

[GoCougs1234]

If I wait till 3,500 RPM I get a major torque limit and 60' times fall to like 1.90 s.

I don't know boost - I'm watching the tach to get the timing right for getting off the brake.

[GoCougs1234]

~750 mile update with lots of launches and WOT driving:

1.) Reinstalled the factory tranny insert - the uber 1-2 shift harshness at WOT and clunky auto downshifting are both gone.
2.) Installed the IE intake and turbo inlet - accel, esp. from a roll, has notably improved (just couldn't force myself to wait for APR's SQ5 intake!).
3.) Neither the CEL nor DTC previous mentioned have returned - APR says to keep checking periodically but generally not a cause for concern but if they do return they'll need logs.
4.) My oil gets hotter much quicker (no surprise!); prior, it took me a lot of work to see 240 deg F, now, that happens fairly easily - APR says to stay with the factory 0w-20 but strongly recommends 5,000 mile change intervals (which I've been doing since going stage 1).
5.) The whistling/air noise has not returned.
6.) The only lingering issue is I periodically get a stumble at WOT 1-2 and 2-3 shifting which feels like hitting a rev limiter to me (if it where a timing or fuel problem I'd think I'd get a CEL/DTC but nope) but I also trip the traction light on such shifts so it just could be losing traction - APR says to video it and get it to them if the issue/concern continues.

Overall, so far, extremely pleased. +175 hp on 91 pump gas, 100% daily drivable, no problems (thus far!) and all for about $9,000 including professional install of the turbo. As stated a number of times I was expecting more from launch control but in hindsight my expectations were probably not realistic as Audi itself does not provide either adjustable RPM or traction-controlled launch control so perhaps the core algo/HW/processing power is not available to implement it via the aftermarket. Even so, just seems to me it could be more repeatable. Either way, not so practical/useful in daily driving, so not much of a deal for me.

[Hostile]

2.) Installed the IE intake and turbo inlet - accel, esp. from a roll, has notably improved (just couldn't force myself to wait for APR's SQ5 intake!).

So you bought the one that multiple people here have said falls apart in less than a year?

[GoCougs1234]

So you bought the one that multiple people here have said falls apart in less than a year.

Is that a question.

[Hostile]

Is that a question.

Yes?

[NBPDC505]

Thanks for the review, glad to get some additional data on what this kit offers.

[GoCougs1234]

Another update.

APR released a patch to fix the aforementioned CEL - had it downloaded last Friday and it has not returned. The DTC has also not returned.

I still have what feels like a bit of a stumble/stutter on WOT 1-2 and 2-3 shifts, but again, no CEL or DTC. APR says no one else has complained. I'm almost always tripping the traction control light on these shifts so it must be just losing traction.

Though the stage 3 TCU WOT non-AMAX 1-2 shift is much stiffer than stage 1 TCU, all other shifts feel softer. It could be these shifts are more performative even though they don't feel as strong? Also, i just can't crack launch control. I have ~40 attempts. For 0-60 times, I managed one each of 3.55 s, 3.64 s and 3.74 s, and all others have been 4.0-4.2 (my average on stage 1) with either no boost or cut boost/torque and 60' times of 1.85+ s.

All in all, still very pleased. No day-to-day problems after the patch. Rating 9/10 thus far (-1 for launch control trickiness but again, not very useful in daily driving). I have a road trip coming up that will be quite the test - heat, elevation, mountain passes, bikes + racks, 500+ lb load, 80-85 mph speed limits, plenty of WOT stings, all for many hours. Stage 1 passed with flying colors, and I suspect stage 3 will as well.

[SQ5onFIRE]

Another update.

APR released a patch to fix the aforementioned CEL - had it downloaded last Friday and it has not returned. The DTC has also not returned.

I still have what feels like a bit of a stumble/stutter on WOT 1-2 and 2-3 shifts, but again, no CEL or DTC. APR says no one else has complained. I'm almost always tripping the traction control light on these shifts so it must be just losing traction.

Though the stage 3 TCU WOT non-AMAX 1-2 shift is much stiffer than stage 1 TCU, all other shifts feel softer. It could be these shifts are more performative even though they don't feel as strong? Also, i just can't crack launch control. I have ~40 attempts. For 0-60 times, I managed one each of 3.55 s, 3.64 s and 3.74 s, and all others have been 4.0-4.2 (my average on stage 1) with either no boost or cut boost/torque and 60' times of 1.85+ s.

All in all, still very pleased. No day-to-day problems after the patch. Rating 9/10 thus far (-1 for launch control trickiness but again, not very useful in daily driving). I have a road trip coming up that will be quite the test - heat, elevation, mountain passes, bikes + racks, 500+ lb load, 80-85 mph speed limits, plenty of WOT stings, all for many hours. Stage 1 passed with flying colors, and I suspect stage 3 will as well.

How can you tell if you have the most current tune? Will it prompt you with the ultra link?

[SQ5onFIRE]

I agree my non launch control 1 to 2 to 3 wot is very hard I like it though feels extremely aggressive normal driving though even a 4 or 5k shift is fast and hard but not as slam into gear head bang. Only wot that happens and I think at least for me all wot shifts are amax because I don’t hear the “farts” sound. All shifts sound like launch control shifts exhaust sound wise. I will have to have someone drive by while I listen outside because I don’t notice non Amax sound from the exhaust.

[GoCougs1234]

How can you tell if you have the most current tune? Will it prompt you with the ultra link?

When I mentioned the CEL to APR they said they had a new patch to address it.

[turbo_911]

So you bought the one that multiple people here have said falls apart in less than a year?

Oh interesting, do you have links to where people said theirs fall apart?

I bought mine right after it came out, so I've had it for over a year. Mine fell apart after a week of use and doing 2-3 launches. All rivets but one were gone lol.
Contacted customer support and they sent me a new one, they also verified all rivets were tight. Also someone from their development team also contacted, worked with them trying to replicate the issue.

I wonder if the rivets they used in their first batch were defective or their tool didn't fully "rivet" them properly.

The replacement that they sent me, still going strong without any issues. I've had it for a year exactly now.

[GoCougs1234]

3 week update:

Only thing to add is the observation that the radiator fans run a lot more.

I drive the snot out of it and no problems. Temps have been very cool in my area so am interested in seeing how things keep cool (I'm expecting no surprises however).

The more I see/hear of Audi's 2025 lineup the more I feel I made the right choice in investing in this vehicle.

[S_Audi_Man]

Thanks for sharing your detailed observations on this upgrade. With regards to your TCU tune, are you using APR's or another vendor's tune? Also have you considered replacing/upgrading your coil packs and spark plugs? I just changed mine out at 60K miles with a stage 1+ E85 IE tune and the whole power band feels smoother for sure. Power also seems to come on smoother and quicker. Just a thought... Lastly, did you upgrade your high pressure fuel pump? When I did, even before I switched to the 1+ file while on 93, it really made a difference in WOT scenarios. I didn't run it like that for long but wanted to see if it smoothed things out before upgrading the tune to 1+. Thanks again for your valiant effort in being an early adopter of APR's new offering and sharing with us!

[GoCougs1234]

Thanks for sharing your detailed observations on this upgrade. With regards to your TCU tune, are you using APR's or another vendor's tune? Also have you considered replacing/upgrading your coil packs and spark plugs? I just changed mine out at 60K miles with a stage 1+ E85 IE tune and the whole power band feels smoother for sure. Power also seems to come on smoother and quicker. Just a thought... Lastly, did you upgrade your high pressure fuel pump? When I did, even before I switched to the 1+ file while on 93, it really made a difference in WOT scenarios. I didn't run it like that for long but wanted to see if it smoothed things out before upgrading the tune to 1+. Thanks again for your valiant effort in being an early adopter of APR's new offering and sharing with us!

My pleasure - so far, so good:

1.) Using APR's stage 3 TCU tune.
2.) Using stock coils and plugs (per APR's recommendation).
3.) Using stock fuel pump. I'm on the 91 octane tune and it is for use only with the stock fuel pump (i.e., there is no 91 tune for an upgraded fuel pump).

[Hostile]

Thanks for sharing your detailed observations on this upgrade. With regards to your TCU tune, are you using APR's or another vendor's tune? Also have you considered replacing/upgrading your coil packs and spark plugs? I just changed mine out at 60K miles with a stage 1+ E85 IE tune and the whole power band feels smoother for sure. Power also seems to come on smoother and quicker. Just a thought... Lastly, did you upgrade your high pressure fuel pump? When I did, even before I switched to the 1+ file while on 93, it really made a difference in WOT scenarios. I didn't run it like that for long but wanted to see if it smoothed things out before upgrading the tune to 1+. Thanks again for your valiant effort in being an early adopter of APR's new offering and sharing with us!

You should not be mixing ECU and TCU tunes from different tuners.

[GoCougs1234]

Another update. I had mentioned multiple times ITT and others about a prominent stutter, though not entirely consistent, on WOT 1-2 and 2-3 shifting. The problem started the day stage 3 was installed so of course I started there; lots of back and forth with APR but NPF. Welp, I was due for a sparkplug change and lo and behold, one of the plugs wasn't even torqued hand tight and may not have even been fully seated in the head (changed by the dealer, who also broke one of the connectors (and I broke some too TBH)!. I'm guessing one can see which sparkplug by evidence of blowby! My best guess is that this only presented on stage 3 (these plugs had ~35k miles of stage 1 with no such stuttering) due to the much higher cylinder pressures vs. stage 1 - it was enough pressure to blow past the untorqued/unseated plug. Also guessing that the stutter was there at times (esp. when I hadn't romped in a while) and not on repeated tests as the blowby remnants (or maybe sharp rise in head and/or sparkplug temp) would temporarily seal the blowby. Not sure why it didn't present in the higher gears. Either way, changed the plugs (AND correctly torqued them of course) and the problem is gone.

[grat_master]

(AND correctly torqued them of course) and the problem is gone.

did you manage to do more runs since you fixed the spark plugs? I'm wondering if it helped to run faster.

[GoCougs1234]

did you manage to do more runs since you fixed the spark plugs? I'm wondering if it helped to run faster.

No, it did not get faster. Turns out the stutter was a tuning issue (aftermarket intake let the turbo spool too quickly to the point of overboost in the shorter gears - APR ginned up a new tune in response and all is fixed).