[JOE ALLAN]

Originally Posted by NHRASuperStock455SD

27.99, 90+ degrees, 50% humidity and it pulled an actual 685HP? That is one killer engine.

Lynn

SIR: You are correct.. In that weather if everything is rite then it is one hell of a motor, Now a question for you Lynn, you are a super stock racer so i think you understand weather correction factors....if you had a motor on a dyno say at a phyical elevation of 1600' and the weather was 93 degrees - the humidity was 50% and the uncorrected barometer was 27.99.. what corrected altilude would this correct to by your numbers? Thank You for any response.........Joe Allan.................ps. not try'n to take anything away from anyone, just try'n to understand.

[Jack Gifford]

I need to point out that I am also in awe of the work on Jim's heads, and have no doubts that it's a killer engine. The only reason I posted here, is to learn why a dyno program (or operater, whatever) would add a "friction" value to the torque measured by the dyno's absorption unit.

[SLICK1]

Originally Posted by 9secdport

I'm confused by all the horsepower numbers. My car dynoed at 540 hp at the rear tires. The car has run consistent low 9.60 to 9.65 all at 140 mph range at 3250 lbs but calculators say it makes roughly 730 hp at the flywheel.

Quite impressive bro! As I've stated earlier, keep up the good work.

[SLICK1]

Originally Posted by 9secdport

Jim I am willing to share any info on the combination. Also would like to hear some suggestions you would have to see if I could pick up a little more power. As always i am looking for anything to be able to drop a few more hundreths. This same combination started running 10.20s in the same car. My father and I have been tweaking on it for the last six years.

Great job!!! Some people have no idea what they are leaving on the table as far as performance is concerned, when they don't do the required track testing or tuning or dyno testing or tuning!!! And lets not forget optimized parts selection? Every combo is different and will require a different selection of parts to get the same results or better as the next man.

[goquick]

If you want the best performance out of your engine without spending all season to find the best tune up, dyno it!!! It isn't always the exact tune in the car, but it will be very close! That leaves you time to #1; not work on it and enjoy the racing more, & #2, if needed, time for sorting out the trans, convertor, and suspension.

[BVR421]

Originally Posted by pontiac jack

I need to point out that I am also in awe of the work on Jim's heads, and have no doubts that it's a killer engine. The only reason I posted here, is to learn why a dyno program (or operater, whatever) would add a "friction" value to the torque measured by the dyno's absorption unit.

Im not sure anyone knows other than the people who make dynos. LOL Maybe a email to Superflow would answer that? FWIW, when Keorner Racing was tuning my HiPort 482, Jeff told me he thought the friction factor was silly because "what motor operates with no friction?" Furthermore the friction tables are pretty generic using bore and stroke to calculate. While making pulls he used the software without a friction correction as his tuning preference, not sure why, then added the correction in when we were finished just so the numbers would be "like every other dyno"
Speaking of pulls, a tractor pulling a sled has to be the ultimate dyno! Go or No Go LOL

[JOE ALLAN]

Jim: Are you sure the uncorrected barometer was 27.99.......I ask people on here about correction factors for weather and for Hp and you'd think it was black magic numbers, no one wants to share.....seems to me with the elevation of your shop plus this bad weather of 93 degrees - 50% humitity - and an uncorrected barometer of 27.99 would be more that a corrected elevation of 1900'.....don't you think.........I guess thoughs that know won't dsay nothing because they are afraid of being wrong and others don't know how to get these numbers they only know how to work a weather station that does the figureing by itself........Can't wait to see you put that engine in your car..........Later.

[NHRASuperStock455SD]

Joe,

I dont have my weather station available right now, but I am guessing between 4000 and 5000 feet corrected. So 685HP could be 785HP at Sea Level conditions easy. This is why the input numbers are so important.

We have this corrected page so we dont have to take our engines to Gainesville Florida to know what it might make there. Rest assured it is a big bump on HP from Indiana. If Abilene is 1900 feet, and the temp was 90, and 50% humidity, 5000 feet is a realistic number.

As soon as I get my weather station back, we can tell you exactly what the Grand Am would run in that type of air verses and actual run. Weather stations turn temperature/barometer/humidity into calculated altitude. Every number above 29.92, 60 degrees and dry air reduces your HP output of the engine. It squeezes out the oxygen.

We usually approximate 1 point in barometer a tenth, and 15 degrees a tenth, and 50% humidity is a tenth. So if Jim took this engine to Gainesville, and all the numbers are correct, just roughly guessing, it would be 5 tenths faster. Another way, 1000 feet a tenth, so I am guessing close to 5000 feet if the numbers are correct.

Lynn

[Old Man Taylor]

I come up with a relative air density of 5493', which is also fairly typical for LACR. The elevation is higher at LACR but the humidity is lower.

[Old Man Taylor]

Duplicate post due to the EXTREMELY slow board.

[Wareagle]

There will always be naysayers--Enjoy your Pontiacs. PONTIAC POWER RULES

[JOE ALLAN]

Lynn and OMT - Thank You for the reply.......I'm not try'n to put Jim down, i'm just try'n to understand the numbers.....and where his correction factors came from, if indeed he did what he said i'll be the first to shake his hand.....you see some one had to make up the numbers for these weather station to begin with and i have a set so i can do them the old way and so far my old numbers come up with in a .001 of what the weather station say's...When my friend put his car together i had figured what i thought he'd run and i guessed at the weather and just took what was available the day before for my figures...... I figured he'd run 127.00 mph in 10.38 seconds and the first run he ran a 127.xx mph in 10.76 et then after they got some rubber down he ran again and ran 127.xx at 10.308.......So correction numbers are close if you look at the whole picture.........I'd put my numbers against anyone weather station....Because weather is just weather and when the track changes there goes your et........My point here is i'll aplaud Jim when he runs the number he should, so far i can't see his numbers make'n sense, not a put down just something isn't rite........Like i said before "IF" he really did what he said then great........I guess time will tell........Good luck Jim.

[JOE ALLAN]

I guess i said enough.....end of my $.02 . See you at the races

[JOE ALLAN]

Racers: I'm going to stretch my $.02 .......I don't think most of you see where i'm come'n from... Go to page #-6 of this post By Jim Robertson then go to post #-107... 5th paragraph down 4 lines: Jim states a "corrected" elevation of 1900' above sea-level..............This is my problen

[Old Man Taylor]

I believe he meant that the actual elevation where the engine was tested was 1900'.

[JOE ALLAN]

Originally Posted by Old Man Taylor

I believe he meant that the actual elevation where the engine was tested was 1900'.

Ok! I can live with that, we all make mistakes, I just wish he would have got on here and corrected what he posted if it wasn't rite........Thank you OMT....Joe

[Jim Robertson]

I realize post 107 is a long and difficult read but it is all there...the terminology is corrrect as are the formulas, the numbers and the correction factors.
Joe: You did mis-qoute me concerning ""corrected" elevation of 1900' above sea-level" in your last post. Not a problem really as I believe I know what you meant but terminology is very important as we delve into the details.

A quote from my post #107:
"Weather conditions observed during testing: Ambient temperature was 93 degrees (note numbers in the CAT (Carburetor Air Temperature) column on the dyno sheet.) Relative humidity was 50% at the beginning of the tests and 49% at the conclusion. Altimeter read a steady 1900 feet (above sea level). Dyno uncorrected barometer was a scant 27.99” Hg (see dyno sheet)."

For a full understanding please take a close look at the whole post. It took over 6 hours to write it out and was intended to assist with:
1) The Pontiac-ers who are hungry for more info;
2) For those who may want to more fully understand their dyno numbers;
And 3) To dispell some myths/misunderstandings about dyno correction factors.

The observed weather conditions the day of our test produce a DENSITY ALTITUDE of 5285' above seal level as computed by my weather station...which is very close to OMT's number and Lynn's guess without his weather station.

The dyno is located southwest of Abilene and is 1820' above sea level static altitude. Static altitude is just that...static. And for what it is worth the static altitude of Abilene Drag Strip is 1719' above sea level. No weather correction required.

On the subject of Altimeters...
An aircraft altimeter is simply a very accurate aneroid barometer. It measures air pressure only. We use the reading in "pressure altitude" for two things: 1)as input in my weather station computer to determine density altitude during racing and 2) vapor pressure during dyno testing. Ours was calibrated by the Precision Measurement Lab on Dyess Air Force Base, the same equipment used to calibrate the altimeters in the B1B and C130 aircraft stationed there. I trust my instruments.

Joe I believe we are together on the numbers with some terminology differences.

Look me up next time your at the Abilene track. I would like to put a face with the name. Good luck.

Jim

[JOE ALLAN]

Jim: Thanks for get'n it straight....I just went out and got my numbers and stuff, this was before i saw you last reply, so using my numbers and using the 1900' because i hadn;t seen you new post that said the phycial elevation of the dyno shop was 1820' i came out with a corrected elevation of 4862'.. now my numbers are always about 400' different that thoughs that use the altimeter because i just correct the uncorrected barometer...(which was -.8 which made the corrected barometer 27.19 - same factor you had) but when corrected .....my figures if your hp is rite for (1820) 1900' the 685 hp does correct to 805+ hp....that said even though we got different ways to get the results we come out with the same final numbers. So far we are on the same page just doing it different.....Ok.....now you say that Abilene drag strip has a static altitude of 1719' which is rite for when the weather is 60 degrees-0humidity and a barometer reading 29.92..........now when we get that bad texas weather it changes the altitude to be more like 3300' thats why when we race we have to use correction factors or a weather station info to change the dial in......i know the static elevation did not change but the poor weather make the car engine feel like its run'n at a higher altitude.....Ok.....Now by my Power to weight figures and useing you T/A weight of 3565lbs. ... and just for example we say the Corrected weather at Abilene raceway is about 1900' (Good Day) you have to divide 3565 by 685 HP giving you a P/W factor of 5.204 which by my numbers says you should run (131.00 in 10.07 et in the 1/4) 1/8 th mile should be close to 107.00 mph in 6.30 if you are using a trans-brake.........with out it maybe 6.55 et....... last time i seen you run you had 10.5'" tires on your car so hook'n is gonna be hard to do unless the track has been prepared......now at sea-level i got close numbers of 139+ mph at 9.55 et in the 1/4 mile and 113+mph in 6.00et for the 1/8 th mile............now this is just my quick figure'n.. not down to the ants ibrow....... the et all depends on the weather conditions and how good the track is........the mph is more easy to figure so it will be closer......now all you got to do is run that thing and we'll see if you got the hp.........them heads are pretty but in life i learned to watch out for things that were pretty.. hahahahahahahaha........now they can all pick on me and leave you alone..........Joe

[Jim Robertson]

I need to admit to the one's still interested in this post...

Here it comes...:-)

We felt an 750HP D port engine was doable a few years ago so we set out to build it. I had the heads, block and crank so that became the limitation. Many calculations and simulations later we could only get to about 730-740HP on paper. We consulted with a few on this board and other places. We then applied all we knew to the head porting, manifold tuning, carburetors, camshafts and rotating assembly. When the results came back as significant as they did we questioned everything. Since October 1, 2006 we have tried to find holes in our program and in the results. The results were beyond expectations and mathematical simulations but we have not found the mistake(s). So, after much review I presented it. Anything new and or unbelievable will meet with skepticism (sometimes harsh). My intention was to encourage others to continue to push the performance envelope. I have been convinced for years it is out there, one just needs to be willing to work very hard to acheive it. There were set backs, stumbling blocks and other obstacles but so far so good. Many good performance parts have been available for years now and I encourage all to patronize the advertisers here. However this is the next level for the old parts. We are not done yet as convertors and manifolds will need tuning.
It will take a nice upgrade to the drivetrain/suspension in the car to make it work and thus it will take a few months to get things sorted out. Hopefully no one will be watching as we struggle to get it performing to our satisfaction...:-) The results are coming.
Jim

[455-4+1]

Thanks for taking the time to post in such detail and be willing to explain procedures and answer questions at length. It all takes time

It keeps the hopes alive for people stuck with cast iron head rules for Pontiacs !!!

Hopefully we will contiune the season over here as started and we will end up with a podium finish in the series in our first year. (3 meetings to go)

We will then be able to chase some sponsorship money and hopefully commision a set of maxed out D-Ports (675-700hp @ 6400 rpm out of 412 inches would be nice) at a maximum of 13:1 of course

Let us know when you have finished with those ones LOL