LS6 to ported FAST 92/90... very disappointing dyno session
07-22-2012 | 01:56 PM
#21
Your camshaft is the reason you didn't pick up as much power, and lost power in other places.
Install a 230/234 or 230/236 camshaft in the car and you should pick power up everywhere. Single pattern camshafts do not and will not ever make sense inside an engine that flows 3x as much intake air as it does exhaust air.
Install a 230/234 or 230/236 camshaft in the car and you should pick power up everywhere. Single pattern camshafts do not and will not ever make sense inside an engine that flows 3x as much intake air as it does exhaust air.
07-23-2012 | 04:38 AM
#23
The difference in power you "feel" is the larger throttle body and the throttle plate movement to incoming air difference (the motor seems to respond faster with any given gas pedal).
07-23-2012 | 08:45 AM
#24
Correct. If you did not change the bolts on the valley cover there is a good chance you could have cracked the bottom of the intake or it could be slightly leaking from not setting all the way down. You might also be fine, but better safe than sorry.
07-31-2012 | 02:52 PM
#25
Ok, please explain your statement, since the correction factors measure temperature and are used to calculate the correction type.
dyno says: "oh gee, its such a hot day" forget it. lets skew numbers. They dont call it 'standard' for nothing.
a) the math is not difficult
b) if the operator has maintained calibrated instruments to measure the air humidity, temperature and pressure... where are these sensors? in the AC room beside the dyno?
There is NO reason why corrected numbers would change because its 'hot' out or its the next day, these statements are complete horseshit. Uncorrected will vary only
Dynos are a precision instrument, and its unfortunate many don't understand how they work, how to use them or how to maintain them or the different types.
07-31-2012 | 11:33 PM
#27
And this^^^
08-04-2012 | 10:23 PM
#29
The correction factor will correct for ambient conditions but will NOT account for timing being pulled due to high IAT. Even pulling a degree of timing out if you are on the edge of optimal timing could easliy explain your disappointment. Also, check those valley cover bolts as has been mentioned. And finally, as the old saying goes, "Take it to the track".
08-09-2012 | 10:02 PM
#30
so ive got a C5Z and thought icould benefit from a nice manifold swap, i sourced a good deal on a Vengeance ported FAST 92 with a ported LS2 throttle body, installed them and these were the results...
dyno session 1:
-77* day
-1.120 correction
-118 tractive effort (loaded dyno)
-21* total timing
-462/434
dyno session 2:
-Vengenace ported FAST 92 w/ ported LS2 90mm TB
-91* day
-1.129 correction
-118 tractive effort (loaded dyno)
-23* total timing
-477/438
MODS:
-stock short block
-livernois stage 3 243's milled to 59-60cc
-230/230 .598 .605 111+2
-vararam with duct
-1 3/4" LT's>3" off road X>Ti cat back
The dyno graph shows loses in HP and TQ in multiple places along the pull and the "gains" being 6,200 rpm to redline (6,800).
BEFORE any timing adjustments were made the car was down on power across the board, A/F being between 12.4-12.7 throughout. Im VERY disappointed in these results.
NOW! i get in the car and i want to say it feels stonger, but maybe that just my brain trying to justify this $900 endevaor lol.. last time i was at the track was 2 saturdays ago and it was ~95*, ill be there tomorrow and the weather is calling for very similar conditions, so we shall see tomorrow if i have any REAL gains, if not, this hunk of plastic (as far as im concerned at this point) is for sale!
thoughts???
dyno session 1:
-77* day
-1.120 correction
-118 tractive effort (loaded dyno)
-21* total timing
-462/434
dyno session 2:
-Vengenace ported FAST 92 w/ ported LS2 90mm TB
-91* day
-1.129 correction
-118 tractive effort (loaded dyno)
-23* total timing
-477/438
MODS:
-stock short block
-livernois stage 3 243's milled to 59-60cc
-230/230 .598 .605 111+2
-vararam with duct
-1 3/4" LT's>3" off road X>Ti cat back
The dyno graph shows loses in HP and TQ in multiple places along the pull and the "gains" being 6,200 rpm to redline (6,800).
BEFORE any timing adjustments were made the car was down on power across the board, A/F being between 12.4-12.7 throughout. Im VERY disappointed in these results.
NOW! i get in the car and i want to say it feels stonger, but maybe that just my brain trying to justify this $900 endevaor lol.. last time i was at the track was 2 saturdays ago and it was ~95*, ill be there tomorrow and the weather is calling for very similar conditions, so we shall see tomorrow if i have any REAL gains, if not, this hunk of plastic (as far as im concerned at this point) is for sale!
thoughts???
Did you re tune the car after the install? That much more air coming into the motor, add more fuel!!
08-09-2012 | 10:30 PM
#31
I don't know what you were expecting. 477 out of a 347 is respectable. I put down less that and my car runs strong. Dyno's are tuning tool, don't live by dyno numbers all they do is break hearts.
Last edited by My6speedZ; 08-09-2012 at 11:06 PM.
08-26-2012 | 09:27 PM
#34
There is a lot of mis information goin on in here. Having a dyno myself my personal car dynos within 2hp from winter months to summer months. It's all in the dyno operators consistency to keep accurate comparable numbers.
Also ignition timing on a NA engine when it is within a couple of degrees from where it makes peak power will not show much difference in power. I've done numerous LS cars and while that timing seems a bit low every setup likes what it likes and if it's pinging audibly with more timing then it either needs timing pulled out like they did or more octane.
I agree that the cam is the reason power didn't change. If it was mine I'd put a 231/242 in it, then it will gain everywhere. That single pattern stuff sucks.
Also ignition timing on a NA engine when it is within a couple of degrees from where it makes peak power will not show much difference in power. I've done numerous LS cars and while that timing seems a bit low every setup likes what it likes and if it's pinging audibly with more timing then it either needs timing pulled out like they did or more octane.
I agree that the cam is the reason power didn't change. If it was mine I'd put a 231/242 in it, then it will gain everywhere. That single pattern stuff sucks.
08-27-2012 | 09:41 AM
#35
With his high compression and depending on squish and combustion chamber his 22.5* timing might be dead on. More timing isn't more power. It all depends on how fast the burn happens to make peak torque at 14* after TDC. A less efficient head needs more timing so having it high is no bragging point. FWIW my FAST 102 gained 15-20 RWHP absolutely everywhere except at 3,400 RPM where it matched the old LS6 mani with 80mm neck and TB (oddly enough I'm at 22.5* max timing). If he lost he has problems other than the manifold.
08-27-2012 | 06:24 PM
#36
^ I agree and that is exactly what I've seen on the dyno. I still have stock 241 heads with a decent size cam with a late IVC point and I'm running 28.5* at peak torque ramping up to 31* at the shift point.
Higher compression and more efficient heads will drastically reduce the "lead time" needed to fully combust.
Higher compression and more efficient heads will drastically reduce the "lead time" needed to fully combust.
08-30-2012 | 05:10 PM
#39
My dyno uses both. It has a probe that goes next to or in the intake tract to measure physical air that is entering the engine and it has a atmousphere factors such as room temperature, humidity and barometric pressure.
My Formula is my test vehicle for consistancy and last winter the car was cam only with LS6 intake and pacesetters. I tested it in 80-90* heat of September and I tested the same combo that winter with 50* temps with bay doors open etc and the readings were within a few HP which is perfectly normal from pull to pull to get a variation from. IMO that's pretty repeatable data.
08-30-2012 | 07:13 PM
#40
to each his own