I just read this after bumping into it while searching for info. I thought it was interesting, so I thought I’d bring the discussion over here.
This was back when EPL launched their tune for the RS4 by putting it on RS MANIAC’s car and showing dynos. The RS4 guys on quattrofail were all creaming in their jeans over the results, but when I looked at them, I thought it would make sense to incorporate some data on the other available tunes at the time (APR and GIAC) to see…was EPL really doing all that much better than the off the shelf APR/GIAC offerings, what with the EPL being a ‘custom tune’?
In my opinion, they weren’t frankly. The custom tune hype was just perfervid RS4 guys hoping for something that sounds elite and fancy lol. Read below and judge for yourself, or offer whatever you want to the discussion.
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It’s nice to see more tuning options available for the B7 Rs4. Recently EPL tuned a car with Milltek downpipes and maybe a catback posted up some results, so I thought it would be neat to compare the GIAC to APR to EPL dynos. I don’t hold much faith in dynos personally as a car that dynos great can lose to a car that is tuned to be more responsive even though it may dyno less…and really we all want our cars to be ‘fastest’ on the street/track but hey, it’s a fun exercise. The cars may all have different modifications, but to my knowledge, all of these dynos are tune delta only. I’ll post the gains % to alleviate the concerns about high reading dynos vs. heartbreaker dynos. Results posted alphabetically.
CAVEATS
a) other mods (like the downpipes on the EPL car) may make the tune deliver not only greater absolute whp/wtq #s, but also greater delta
b) octane on GIAC was only 91, vs 93 on APR and ?? on EPL (prob 93 as EPL are in the northeast where 93 is abundant)
c) not sure on the timing of all dynos, if there were same day etc. I believe they were, but someone will correct me if that is not the case as that could be a factor for non-enclosed dyno rooms
d) I’m pretty comfortable saying that all before/after dynos were done after a carbon cleaning. If cleaning was done in between pre-tune/post-tune dynos, that would throw off the gains (and that company would need to be burned to the ground).
*** It would be nice to get more results added in…I doubt JHM will post dyno #s for a tune, but hey, I’ve asked them anyway.
APR dyno on their in-house Dynapack - 93 octane
+5.4 % gain peak WHP (at around 7300 rpm)
+2.5 % gain peak WTQ (at around 3300 rpm)
EPL dyno on their in-house Mustang - 93 octane
+4.7 % gain peak WHP (at around 7000 rpm)
+9.3 % gain peak WTQ (at around 3600 rpm)
GIAC dyno on their in-house Mustang - 91 octane
+3.9 % gain peak WHP (at around 7600 rpm)
+3.7 % gain peak WTQ (at around 3600 rpm)
APR dyno plot (converted to crank hp) on their in house Dynapack - 93 octane
http://www.goapr.com/news/wp-content/uploads/2011/03/raw-rs4-stage-1-sae-wheel-all.png
GIAC dyno plot on their in-house Mustang - 91 octane
http://www.giacusa.com/images/austin/RS4/RS4_91_pump_final.gif
EPL dyno plot on their in house Mustang dyno - 93 octane
http://brianja.smugmug.com/photos/1223528798_k9xSW-XL-1.jpg
Here’s an interesting question (another big caveat) - the RS4 STOCK map has a torque limiter, correct? Gears 1-3 the car restricts throttle (thus torque) below 5000or so RPM, to about 52% as long as the temps are cold. As ambient temps climb, the effects of the limiter diminish. i.e. when it’s 70-80 it’s minimal…when it’s 40-50 it’s significant. If someone has the actual data, that’d be great. What I’m getting at is that this effect could make the torque/hp delta below 5000rpm look quite a bit bigger than it would be if say the temps were warmer/above those thresholds. To that end:
•EPL car dyno’d in Connecticut last Saturday at 11 am (freezing cold weather)
•APR car dyno’d in hot Alabama
•GIAC car dyno’d in hot California
Well, its about 9% gained tq for epl vs about 3-4 % for the other guys
A couple of reasons?
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The epl car was tuned with downpipes that had high flow cats…thus its better equipped to take advantage of the exhaust to make power. I reckon the other tunes would have a better tune-only tq delta if they had downpipe mods too. They were bone stock. I’m not saying the downpipe gains are in there…they’re not. I’m saying the tune can deliver slightly better torque delta thanks to the dps. This mayy be 1 or 2% of the delta. Guess though.
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The EPL car dynod in ice cold connecticut last saturday morning. It was about 40 degrees. APR dynod last year in Alabama…at likely far warmer temps. What does this mean? The stock tune inhibits throttle below 5000rpm or so when its cold out. We can guess that this is about 5-10 wtq. I’m sure someone knows exactly. That would be another 2-4% of the diff.
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Epls tune is better. This is up for debate…I have no idea as we’ve only known about it for a couple of days.
So if 1 and 2. are true, that accounts for basically all of the difference.
Its interesting to note that above that tq limiter range (5250-8250 RPM)_…where we can make an apples to apples comparison, APR added more hp than did EPL.
I don’t think anyone should expect a custom tune to add much vs an ots tune when you’re talking catback and dps…and maybe intake manifold work. Custom is nice because you can tell the tuner certain things you want…like I’d love my jhm tune to have a rev limit at 7100rpm for aall geaars…as I sometimes rip through into the 7300+ range when I get carried away. (That’s on my S4 with a 7000 rpm redline).