SIC LSX

iTrader: (10)

ok i dynoed and my numbers were 384whp 360trq "UNCORRECTED" Where should it be if it were corrected? The temp was about 85deg around 80% humity and at seal level.

I have put a ported T.B on it now to so im guessing that is about 10whp and will be getting a underdrive pulley on it soon to for another 10whp

dynocar

We would need to know your actual barometric pressure during the test before a correction factor could be given. At sea level this pressure does vary. But for the sake of discussion, let's assume that the pres was 29.92, this would give you a 1.021 SAE J1349 Rev 90 correction factor. Now let's say that the baro pr was 29.52, this would be a 1.037 corr factor. I cannot understand why any professional dyno shop would not use the accepted SAE correction. If you go back with some changes for a re-dyno, your new numbers cannot be accurately compared to your first, hope they are cheap.

bshell

iTrader: (24)

I was at the shop with Dan. They did use a correction factor but we realized later that they had some strange environmental readings. The file shows 88F, 35% humidity, and 4500ft elevation(!). It also gives absolute pressure as 30.0in-hg and vapor pressure as 0.5 in-hg. Actual readings per the weatherunderground website were: 30.02 in-hg, 60% humidity, 81F, and actual elevation is <50ft above sea level.

dynocar

I'm confused, if the report stated, "UNCORRECTED", to me, my logic would indicate that the results were raw and no corrections were computed even if they used were entered. You can't really go by weatherunderground info because if the dyno is in a building, the temp and humidity get changed. I'm assuming that the dyno was a DynoJet and maybe someone with more knowledge on that brand and its terminology could set us strait here.

DRSITES

iTrader: (3)

Can't offer any help here, just wanted to add myself to the list of people who are baffled as to why they would have run it with uncorrected #s. Other than that, your p&p TB will give you somewhere between 4-6rwhp, and between 5-10rwhp from the pulley. When you go to dyno, always keep the lows in mind, if you go in expecting to get the top gains for every mod, you'll always be disappointed.

SIC LSX

iTrader: (10)

my corrected #'s were about 10hp lower but they had some strange environmental readings!!!!

The file shows 88F, 35% humidity, and 4500ft elevation(!). It also gives absolute pressure as 30.0in-hg and vapor pressure as 0.5 in-hg. Actual readings per the weatherunderground website were: 30.02 in-hg, 60% humidity, 81F, and actual elevation is <50ft above sea level.

SIC LSX

iTrader: (10)

as far as the ported TB and pulley i was just going off everything i have read on this site and what peoples gains with these mods and seen in person at dyno!

SIC LSX

iTrader: (10)

Bump!! someone has to have and idea! im sure its about 10hp higher

SIC LSX

iTrader: (10)

???? bump!!!!

'Trust'

iTrader: (24)

SAE as a general rule are lower than STD, they should be able to pull up your graph and change it to SAE. For comparison, one person put down 374 RWHP STD, and SAE the numbers were 362

HOSS

iTrader: (12)

SAE numbers are more than likely going to be lower, my uncorrected numbers for my dyno day were 440/401

SIC LSX

iTrader: (10)

well talked to dyno shops here and they toldm e here in hawaii it is about 10whp more corrected

Lady Redhawk

iTrader: (6)

On all the dyno tunes I have done, I see between 8 to 12 hp difference. Most have been right at 10 hp. This is on all different weather conditions, with mildly modded cars up to 408 ci power houses.

I get more change in HP numbers from going to different dynos. It depends on how the dyno is calabraded with elevation, weather, etc. The only real comparisons that can be made is by using the same dyno and looking at the same correction factors, whether SAE or STD. But comparing your dyno numbers with someone elses from a different dyno isn't a good comparison. The biggest difference I have seen was on 2 cars that had dynos done from out of town. One was about an 1 1/2hr away the other 4hrs away. With nothing else changed on these cars one had 20 less HP and the other one had 35 less HP numbers on the dynos in our area. Only after tuning did they get their numbers back and then some. But, I am sure it they went back to the other dynos their numbers would have been even higher.

HolyShiznit

iTrader: (11)

I always dyno uncorrected because I don't give a **** about correction factors, numbers are just that......numbers. Take your UNCORRECTED numbers and dyno again with your new mods UNCORRECTED. There is your gain. People get so enraptured in dyno numbers....it's a tool for tuning.

Lady Redhawk

iTrader: (6)

You said that so much better than I did. Right to the point.

dynocar

So you're stating that if you do a dyno baseline one day, make a mod, and re-dyno another day and lose 10 HP, you will conclude that the mod is bad, even if it was actually caused by the difference in weather conditions? I've seen that much of a change take place on a given tuning day with a low pressure front moving thru, but using corrections prevented inaccurate tuning conclusions. I'm glad you're not my tuner.

HolyShiznit

iTrader: (11)

^^^ No tuner on the planet is going to make any changes without at least making a baseline pull for the day. That becomes your baseline to tune from. A low pressure front moving through is not going to drastically through off the dyno unless it is something absolutely absurd ie: Hollywood style.

If I dyno in 65 degree weather, slap on an air intake and then dyno on a 95 degree day and expect amazing numbers then I am oblvious to reality. My whole point was to not get caught up in the numbers themselves. Correction factors have people freaking out all the time and honestly the LS1 guys are more bitchy about it than when I was back with the import crowd.

dynocar

Using your numbers, if you dyno at 65 degree, then dyno on a 95 degree day, with no other atmospheric changes (humidity or baro pres), you will loose around 20 HP on a 300 HP with no engine changes. Now consider some baro pr drop and more humidity, and your HP drop will be much more. How can anyone make any intelligent tuning decisions with such potential measurement spreads? It makes no sense to me why anyone would operate a dyno and not use an accepted standard of measurement that helps to negate such questionable dyno info.

HolyShiznit

iTrader: (11)

^^^ Dyno operators are different from their USERS. I just run uncorrected numbers because I want the actual wheel horsepower numbers I am spitting out that day, not some artificial representation of equivalent conditions. And because it's hillarious to watch the bitch fests of correction factors.

As I stated before, you do a baseline run to see where you are at. THEN you tune. Regardless of correction factor you ALWAYS run off of a baseline. If you hit 365 on your baseline, and after tuning you hit 375 then you gained power, that will show REGARDLESS of correction factor. THe point is that you GAINED, who gives a **** if the correction factor makes it 10-15rwhp, let the Supra boys argue peak power.

dynocar

Ok, so if you run at a drag strip on a hot, humid, low baro pressure day, then you come back with some mod on a cold, dry high baro pres day, all of the changes are do to the mod??? Same thing on a dyno.