Dynamometer Results & Comparisons - LS6 to ported FAST 92/90... very disappointing dyno session

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???

:corn:

The temperature difference on the dyno can skew numbers dramatically. It all matter what the 1320 says. It should be a 2-4 mph gain around .2-3 drop in et.

You increased the size of the runners without increasing the demand from the motor. Bigger is not always better. I'm sure you will be happy with it in the long run, but put more cubes in the bottom end and you will see the difference that will really make you happy. You just need the ability to move more air in order to use a larger intake. Even still 477whp is a very respectable number...

I was under the impression the correction factor would keep things semi consistent.

I thought I wa moving enough air to take advantage of the manifold. I'm also at ~11.5:1 compression.

If you didn't dyno on the same day or at least close, the numbers mean jack.

But even then it shows a fairly normal gain in power of 15hp. Not sure what you were expecting?

If you didn't dyno on the same day or at least close, the numbers mean jack.

But even then it shows a fairly normal gain in power of 15hp. Not sure what you were expecting?



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.


.....

If you didn't dyno on the same day or at least close, the numbers mean jack.

But even then it shows a fairly normal gain in power of 15hp. Not sure what you were expecting?

This...


Respectable gains and it was much hotter on this dyno run. With it being as hot as it is right now, don't expect miracles at the track either. This heat won't be friendly for your e.t's or traps. Take that into consideration. Ive never heard a legit disappointing story about a FAST "92" that was correctly setup.

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.

If you didn't dyno on the same day or at least close, the numbers mean jack.

But even then it shows a fairly normal gain in power of 15hp. Not sure what you were expecting?

I was under the impression the correction factor would keep things semi consistent.

I thought I wa moving enough air to take advantage of the manifold. I'm also at ~11.5:1 compression.

First off, you certainly are moving enough air to take advantage of a bigger intake.

thunderstruck507- with the power numbers he was already making I'm sure he wasn't expecting to be losing HP and TQ in multiple places along the rpm range. As long as he dyno'd on the same dyno the two different outside temps (77* and 91*) shouldn't make a whole lot of difference, the correction factor is there for a reason. Only making decent gains at the peak is not respectable gains, nor fairly normal in this case.

But OP hopefully next time you hit the track you have very similar weather conditions as the last and you pick up some speed to reverse that disappointment. Good luck!

Hit the track first and see how the car responds. I won't be worried about the numbers

Did you confirm there are no vacuum leaks and that the car is getting WOT at the blade?

Did you change the valley cover bolts?

Did you do multiple pulls with the same result?

Sounds like there are other issues, you should have gained more

seems about right considering the dyno temp differences.When i went from the stock ls6 intake with ported throttle body to my ported fast 90/90 setup i gained 20rwhp and 17rwtq just fwi

Did the tuner even both seeing if it liked more timing? 21-23 seems pretty low to me.

i ran that much timing with a 175 shot of nitrous on pump gas and more compression.... it needs to be up closer to 28*

Just left my tuner. Put the timing back down to 21.5. 23 was pinging pretty hard today in 3rd gear in this 90* heat. You have to remember I'm in California with 91 octane and I'm at damn near 11.5:1.

i ran that much timing with a 175 shot of nitrous on pump gas and more compression.... it needs to be up closer to 28*

You have a magical vehicle or are mis-informed. 28*, 175 shot and 91 octane would be a shit show lol

Did you confirm there are no vacuum leaks and that the car is getting WOT at the blade?

Did you change the valley cover bolts?

Did you do multiple pulls with the same result?


What does this do? New to me, and curious?

You have a magical vehicle or are mis-informed. 28*, 175 shot and 91 octane would be a shit show lol

He's saying he ran 175 shot with 23 degrees and that the OP who is all motor should be running more than 23 ;)

16 degrees ambient air temp will make a very noticeable difference. Each motor is different but timing doesn't seem quite right. Was the A/F adjusted at all? A FULL tune is needed to optimize a FAST install.

What does this do? New to me, and curious?

Stock style valley cover bolts stick up to high and does not allow the fast 92/102 intakes to seat properly.

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.

Correction factors do not make up for what is lost on such a hot day.

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).

Stock style valley cover bolts stick up to high and does not allow the fast 92/102 intakes to seat properly.

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.

Correction factors do not make up for what is lost on such a hot day.


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.

Correction factors do not make up for what is lost on such a hot day.

Why not? As vmapper said, please explain.

Did the tuner even both seeing if it liked more timing? 21-23 seems pretty low to me.

This^^

Just left my tuner. Put the timing back down to 21.5. 23 was pinging pretty hard today in 3rd gear in this 90* heat. You have to remember I'm in California with 91 octane and I'm at damn near 11.5:1.

And this^^^

Looks like more ammunition for "I hate fast intakes" bandwagoners...

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".

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???

:corn:

Could've been worst guy, you could've lost HP/TQ... I know after spending $$$ on something you don't NEED but want and have high expectations, then let down...

Did you re tune the car after the install? That much more air coming into the motor, add more fuel!!

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.

Ok its been a month.... ....track numbers?

i ran that much timing with a 175 shot of nitrous on pump gas and more compression.... it needs to be up closer to 28*

this.

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.

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.

^ 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.

time for a cam swap

Was the air temp measured in the dyno room or intake air temp? 9x* blowing across the engine and trying to cool the engine bay vs 7x* can be a big difference in intake temps.

Was the air temp measured in the dyno room or intake air temp? 9x* blowing across the engine and trying to cool the engine bay vs 7x* can be a big difference in intake temps.

Thats a very good point. Alot of people don't take that into consideration... Also temperature alone is only part of the equation. You need barometric pressure and humidity along with physical elevation (for some barometric pressure sensors) to get an accurate reading. False heat that the temp unit doesn't pick up but the car is seeing will also skew numbers.

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.

Looks like more ammunition for "I hate fast intakes" bandwagoners...

Nobody, let me repeat nobody hates FAST 90/92/102 IM....

now the 102 TB :judge: to each his own

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.

It's pretty sad that I went back and looked through this thread and NO ONE has acknowledged the fact that I posted the problem reason & solution for this issue.


Carry on discussing your internet formula's and air temp debates. :thumb:

It's pretty sad that I went back and looked through this thread and NO ONE has acknowledged the fact that I posted the problem reason & solution for this issue.


Carry on discussing your internet formula's and air temp debates. :thumb:

I did lol :burn:


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.

Just got a new black fast 92 installed with a stock ls2 tb and picked up 30 wheel and 50 tq at 4.6k, dyno cf was 1.04

Intake ported by Joe at Vengeance