Dyno #'s 94' S4
Discussion
I had my S4 Dyno tested yesterday, before and after having a custom exhaust fabricated.
Modifacations at time of first dyno run,
-330 HP chip from P.U.K.
-K&N air filter
-Punched out cat
-3 chamber flow master muffler/single right side exit
Max power 266 rwhp at 5600 rpm
Max torque 262 ft-lbs at 3600 rpm
With an estimated average drive line loss of 18% that put engine HP at about 313, thats almost a 50 hp gain over stock trim.
Now after the first dyno run, we removed the entire exhaust system and constructed a new one out of 3" stainless steel. All piping was manderal bent and joints were TIG welded. Muffler was replaced with a 2-chamber flowmaster crossflow model (3" inlet/ dual 2.5 outlets)
After the new exhaust was fabricated and hung we did a follow-up dyno run to judge any improvements.
Max power was 262 rwhp at 5400 rpm
Max torque was 292.8 at 3600 rpm!
Top end power may have suffered, but maybe not for long. Air/fuel ratio during the first run was on the order of 12.5 to 13 to 1 in the peak power rpm range.
Air/fuel ratio after the exhaust change was in the area of 14.5 to 15.5 to 1 in the peak power rpm range.
As you can see the larger exhaust really leaned out the mixture, but with time, the adaptive properties of the computer hopefully will richen things up a bit. Then there will more than likley be a significant gain in top end power over the initial posted numbers.
Forget top end power, look at the torque gain at the low end (30 ft-lbs)! This equated to a 20 hp gain from 3200-3800 rpm, that's some serious low end grunt.
I can definetly say with my first run down the road that there was a substantial gain in low end power (lots of wheel spin in 2nd gear with only part throttle)
At a later date I will probably dyno the car again after the computer has learned to run with the new exhaust.
Which BTW sounds wicked!!!
* these hp ratings would be higher in real world conditions with proper air flow across the charge cooler radiator.
>>> Edited by mikelr on Friday 17th October 20:36
Modifacations at time of first dyno run,
-330 HP chip from P.U.K.
-K&N air filter
-Punched out cat
-3 chamber flow master muffler/single right side exit
Max power 266 rwhp at 5600 rpm
Max torque 262 ft-lbs at 3600 rpm
With an estimated average drive line loss of 18% that put engine HP at about 313, thats almost a 50 hp gain over stock trim.
Now after the first dyno run, we removed the entire exhaust system and constructed a new one out of 3" stainless steel. All piping was manderal bent and joints were TIG welded. Muffler was replaced with a 2-chamber flowmaster crossflow model (3" inlet/ dual 2.5 outlets)
After the new exhaust was fabricated and hung we did a follow-up dyno run to judge any improvements.
Max power was 262 rwhp at 5400 rpm
Max torque was 292.8 at 3600 rpm!
Top end power may have suffered, but maybe not for long. Air/fuel ratio during the first run was on the order of 12.5 to 13 to 1 in the peak power rpm range.
Air/fuel ratio after the exhaust change was in the area of 14.5 to 15.5 to 1 in the peak power rpm range.
As you can see the larger exhaust really leaned out the mixture, but with time, the adaptive properties of the computer hopefully will richen things up a bit. Then there will more than likley be a significant gain in top end power over the initial posted numbers.
Forget top end power, look at the torque gain at the low end (30 ft-lbs)! This equated to a 20 hp gain from 3200-3800 rpm, that's some serious low end grunt.
I can definetly say with my first run down the road that there was a substantial gain in low end power (lots of wheel spin in 2nd gear with only part throttle)
At a later date I will probably dyno the car again after the computer has learned to run with the new exhaust.
Which BTW sounds wicked!!!
* these hp ratings would be higher in real world conditions with proper air flow across the charge cooler radiator.
>>> Edited by mikelr on Friday 17th October 20:36
Nice numbers! I also dynoed my 90 SE and came up with similar numbers with mine. But, mine is very rich, not like yours at all. You can check the dyno plot here:
<a href="http://www.gt40s.com/images/lotusearp.jpg"><a href="http://www.gt40s.com/images/lotusearp.jpg"><a href="http://www.gt40s.com/images/lotusearp.jpg">www.gt40s.com/images/lotusearp.jpg</a></a></a>
This was on a Dynojet at a shop that does a lot of build ups and racing. Peak hp=267 and peak torque was 285. I'm running the Hi torque chip with 1.1 bar max boost and a homemade free-flow exhaust (Flowmaster with all mandrel bends like yours) with no cat. I'm planning on a turbo upgrade before too much longer as we detected some surging.
Did you notice any surging with your runs?
Funny thing is when I posted these results over on the Yahoo Esprit forum I caught all kinds of hell for estimating 15-25 rear wheel hp from the exhaust change alone. Oh well, doesn't really matter to me what the gains were just that I knew an improvement had been made. Nice to see someone back it up as I didn't have the time (still might do it) to take the exhaust back off and dyno stock.
Best,
Ron
>> Edited by rlearp on Sunday 19th October 03:01
<a href="http://www.gt40s.com/images/lotusearp.jpg"><a href="http://www.gt40s.com/images/lotusearp.jpg"><a href="http://www.gt40s.com/images/lotusearp.jpg">www.gt40s.com/images/lotusearp.jpg</a></a></a>
This was on a Dynojet at a shop that does a lot of build ups and racing. Peak hp=267 and peak torque was 285. I'm running the Hi torque chip with 1.1 bar max boost and a homemade free-flow exhaust (Flowmaster with all mandrel bends like yours) with no cat. I'm planning on a turbo upgrade before too much longer as we detected some surging.
Did you notice any surging with your runs?
Funny thing is when I posted these results over on the Yahoo Esprit forum I caught all kinds of hell for estimating 15-25 rear wheel hp from the exhaust change alone. Oh well, doesn't really matter to me what the gains were just that I knew an improvement had been made. Nice to see someone back it up as I didn't have the time (still might do it) to take the exhaust back off and dyno stock.
Best,
Ron
>> Edited by rlearp on Sunday 19th October 03:01
Do you have a scan of your plot? It'd be interesting to see. I have a PUK chip too (actually have a new one and I'm selling the old one at: <a href="http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=33597&item=2437300600">http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=33597&item=2437300600</a>
and. In everyday driving is seems reasonable, although surge is still there and I think it is compressor surge at the higher boost levels due to the ratehr conservative compressor stage.
Ron
>> Edited by rlearp on Sunday 19th October 03:05
and. In everyday driving is seems reasonable, although surge is still there and I think it is compressor surge at the higher boost levels due to the ratehr conservative compressor stage. Ron
>> Edited by rlearp on Sunday 19th October 03:05
Sorry, all I have at this time are the hard copies, and I don't own a scanner:-(
I had the high torque chip also before switching to the 330HP, I thought that the power cam in to abrupt.
The new chip is alot smoother and the top end feels alot better (even know the dyno doesn't show much different).
I had the high torque chip also before switching to the 330HP, I thought that the power cam in to abrupt.
The new chip is alot smoother and the top end feels alot better (even know the dyno doesn't show much different).
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