Correlation between Corrected Horspower and at the track

aedcarburetors · Post by **aedcarburetors** » Fri Dec 23, 2005 9:28 pm

Just a few questions . We purchased a turnkey late 90s NHRA Pro Stock . Best et for the Engine was 7.09 when leased by Robert Patrick from Ralpph Ferra. Engine showed 1275HP at the track. Engine was freshened and returned to Ralph whio then slotted it back onto his PRobe and apparently hasnt raced it since it was freshened. Also I was told that they Got another 20 more steam from the engine in the freshen up with different exhaust valves, and upping compression 1/2 point.

We pulled engine out and put it on the pump just to get a baseline here yesterday ...yesterday was a pretty hot day here in Brisbane and room was at 3800-3900fy with 20.55% O2 1.07 HP Correction.

Did 7 pulls on C25 Best corrected HP was 1099.5 HP at 8700 peak TQ was 721 Ft-Lb at 7300RPM. Brake Speficic was spot on at .400.

Only thing that wasnt right and we are correcting it next week is the Collector had to be effectively lengthend with a 4.5 inch bend to hook up to the 6 inch Dyno Cell exhasut.. but i done think this would have a 175HP effect or would it........ aslso my question to you guys is with scoop pressure etc what does this correlate to HP at the track etc with your experience......also we were ramping the engine at 600RPM/sec. Bellow is Dyno sheet and PIc of Exhaaust

Post by **maxracesoftware** » Fri Dec 23, 2005 10:35 pm

Just a few questions . We purchased a turnkey late 90s NHRA Pro Stock . Best et for the Engine was 7.09 when leased by Robert Patrick from Ralpph Ferra. Engine showed 1275HP at the track. Engine was freshened and returned to Ralph whio then slotted it back onto his PRobe and apparently hasnt raced it since it was freshened. Also I was told that they Got another 20 more steam from the engine in the freshen up with different exhaust valves, and upping compression 1/2 point.

We pulled engine out and put it on the pump just to get a baseline here yesterday ...yesterday was a pretty hot day here in Brisbane and room was at 3800-3900fy with 20.55% O2 1.07 HP Correction.

Did 7 pulls on C25 Best corrected HP was 1099.5 HP at 8700 peak TQ was 721 Ft-Lb at 7300RPM. Brake Speficic was spot on at .400.

Only thing that wasnt right and we are correcting it next week is the Collector had to be effectively lengthend with a 4.5 inch bend to hook up to the 6 inch Dyno Cell exhasut.. but i done think this would have a 175HP effect or would it........ aslso my question to you guys is with scoop pressure etc what does this correlate to HP at the track etc with your experience......also we were ramping the engine at 600RPM/sec. Bellow is Dyno sheet and PIc of Exhaaust

Code: Select all


CID= 499.665      --- Fuel Consumed in Lbs/Hour ---
	CFM @	12.5:1	13.2:1	14.0:1	14.7:1	16.0:1	Fuel	Engine
Engine	125.0	 A/F	 A/F	 A/F	 A/F	 A/F	Heat	Friction
 RPM	Ve %	Lbs/Hr	Lbs/Hr	Lbs/Hr	Lbs/Hr	Lbs/Hr	 HP	HP
6500	1174.7	344.2	325.9	307.3	292.7	268.9	2446	185.9
6600	1192.8	349.5	330.9	312.0	297.2	273.0	2484	192.1
6700	1210.9	354.8	336.0	316.8	301.7	277.2	2521	199.3
6800	1228.9	360.1	341.0	321.5	306.2	281.3	2559	207.0
6900	1247.0	365.4	346.0	326.2	310.7	285.4	2596	214.8
7000	1265.1	370.7	351.0	330.9	315.2	289.6	2634	222.7
7100	1283.1	375.9	356.0	335.7	319.7	293.7	2672	230.8
7200	1301.2	381.2	361.0	340.4	324.2	297.8	2709	239.0
7300	1319.3	386.5	366.0	345.1	328.7	302.0	2747	247.4
7400	1337.4	391.8	371.1	349.9	333.2	306.1	2785	255.8
7500	1355.4	397.1	376.1	354.6	337.7	310.3	2822	264.6
7600	1373.5	402.4	381.1	359.3	342.2	314.4	2860	273.8
7700	1391.6	407.7	386.1	364.0	346.7	318.5	2897	283.2
7800	1409.6	413.0	391.1	368.8	351.2	322.7	2935	292.7
7900	1427.7	418.3	396.1	373.5	355.7	326.8	2973	302.4
8000	1445.8	423.6	401.1	378.2	360.2	330.9	3010	312.2
8100	1463.9	428.9	406.2	382.9	364.7	335.1	3048	322.1
8200	1481.9	434.2	411.2	387.7	369.2	339.2	3086	332.2
8300	1500.0	439.5	416.2	392.4	373.7	343.4	3123	342.5
8400	1518.1	444.8	421.2	397.1	378.2	347.5	3161	353.4
8500	1536.2	450.1	426.2	401.9	382.7	351.6	3199	364.4


CID= 499.665      --- Fuel Consumed in Lbs/Hour ---
	CFM @	12.5:1	13.2:1	14.0:1	14.7:1	16.0:1	Fuel	Engine
Engine	125.0	 A/F	 A/F	 A/F	 A/F	 A/F	Heat	Friction
 RPM	Ve %	Lbs/Hr	Lbs/Hr	Lbs/Hr	Lbs/Hr	Lbs/Hr	 HP	HP
8600	1554.2	455.4	431.2	406.6	387.2	355.8	3236	375.6
8700	1572.3	460.7	436.2	411.3	391.7	359.9	3274	387.0
8800	1590.4	466.0	441.3	416.0	396.2	364.0	3311	398.5
8900	1608.4	471.3	446.3	420.8	400.7	368.2	3349	410.2
9000	1626.5	476.6	451.3	425.5	405.2	372.3	3387	422.0
9100	1644.6	481.8	456.3	430.2	409.7	376.4	3424	434.0
9200	1662.7	487.1	461.3	435.0	414.2	380.6	3462	446.7
9300	1680.7	492.4	466.3	439.7	418.7	384.7	3500	459.5
9400	1698.8	497.7	471.3	444.4	423.2	388.9	3537	472.6
9500	1716.9	503.0	476.4	449.1	427.7	393.0	3575	485.8
9600	1735.0	508.3	481.4	453.9	432.2	397.1	3612	499.1
9700	1753.0	513.6	486.4	458.6	436.8	401.3	3650	512.7
9800	1771.1	518.9	491.4	463.3	441.3	405.4	3688	526.4
9900	1789.2	524.2	496.4	468.0	445.8	409.5	3725	540.3
10000	1807.2	529.5	501.4	472.8	450.3	413.7	3763	554.4
10100	1825.3	534.8	506.4	477.5	454.8	417.8	3801	568.6
10200	1843.4	540.1	511.5	482.2	459.3	422.0	3838	583.1
10300	1861.5	545.4	516.5	487.0	463.8	426.1	3876	597.6
10400	1879.5	550.7	521.5	491.7	468.3	430.2	3914	612.4
10500	1897.6	556.0	526.5	496.4	472.8	434.4	3951	627.3

still haven't figured out how to format this data

but from your Fuel Consumed in Lbs/Hour
the A/F Ratio is on the "lean-side"
and usually the peak Ve% is somewhere between Peak TQ RPM
and Peak HP RPM..but yours is above the Peak HP RPM

along with VE% Curve having multiple peaks and valleys , this shows
Intake and Exhaust Systems not working together in your desired RPM range

Post by **maxracesoftware** » Fri Dec 23, 2005 10:43 pm

download and run this program and see if ET/MPH incrementals
correlate to your Dyno and DragStrip data ????

http://www.maxracesoftware.com/products.htm
ET_Analyst for DragRacers ETAVBWIN version 1.00

Load the PROSTOCK file (its default anyways)
and adjust Inputs to match your Dyno Track Data and see how close it is

also your 69.0 Ve% is multiplied by 2 = 138.0 VE at 8900 RPM
your Fuel Consumed at 8700 RPM = 395.8
thats right about 14.4:1 ..thats pretty close to what i like to see
on my Dyno at 600 RPM/SEC on this kind of Engine
maybe still lean ?

your A/f Ratios also get doubled like your 8.90 at 8700 rpm = 17.8:1
so thats showing the Air Turbine may be calibrated too high
(along with your 138.0 Ve readings ) probably your BSAC's are showing
high, maybe into 6's(when doubled)

also your Torque is way too low
again showing too large taper + too short intake runner
to tune-in at 8700 rpm..that could be splitting up the Ve Curve
along with adding exhaust pipes/mufflers to Headers

Post by **maxracesoftware** » Fri Dec 23, 2005 11:13 pm

http://www.maxracesoftware.com/Dyno_Wire_Cover3.jpg

i know your Fuel Consumed Curve looks about OK ,
but i thought i might pass this Info along to you and others

if you look at that Pic of my Harwood Dyno Fuel Cell,
there's a little round Chrome Vent on the Cap,
underneath this Chrome Vent Cover was only (1) .060" hole
and coupled together with the fact that Chrome Cover as it came
from Harwood was dug-in and sunken into the plastic enough to
further choke off venting ...result was => around 900 HP i was actually running out of gasoline ......i removed that Chrome Cap and drilled
5 more holes then placed a washer so the cover wouldn't sink into the
plastic to get full venting...this result was i now had enough fuel
flow for 2500 HP on gasoline .(there's also a return line that can't be seen)

its important to get very adequate venting and return to gas tank
from your Dyno Fuel System.

shawn · Post by **shawn** » Sat Dec 24, 2005 12:09 am

Hi,
As much as most of us would like the dyno numbers to line up with the track numbers, they usually don't.Larry's probably got the only system in the country that does. Lol. I know that prostock guys now will take their engines to a competitors dyno just to try and get numbers that make sense. I would tune it for trends and put it in the car and see what happens.
Shawn

aedcarburetors · Post by **aedcarburetors** » Mon Dec 26, 2005 5:22 pm

thanks larry... your software is pretty accurate ... do you know of any good clutch software

Post by **maxracesoftware** » Mon Dec 26, 2005 5:35 pm

i haven't yet tried this Software out ,
but Patrick Hale's website has a few ScreenShots/Data Pics
you might Email him for additional Info ?

http://quarterjr.com/clutch_pro.htm

also checkout his other Software such as
Quarter Jr and the Professional Versions

TSTOM · Post by **TSTOM** » Tue Dec 27, 2005 1:34 pm

Please tell me that is not an aluminum bell housing on your dyno

I may be able to hook you up with a guy for clutch info ....let me check with him and see if he is able to take new work at this time

Tom

MadBill · Post by **MadBill** » Tue Dec 27, 2005 3:43 pm

With such a relatively large engine and matching collector size (5"?), I wonder if the step up to the 6" dyno exhaust 'looks' like a big, long collector to the engine, instead of representing open atmosphere? Any chance of a pull with open, as-raced collectors?

dbusch · Post by **dbusch** » Wed Dec 28, 2005 10:35 pm

looks like a lot of power drop above peak hp. Your cfm reading was showing some possible valvetrain issues too, since it stopped increasing sooner than it should have. Is this a 55mm cam? What intake lobe lift, rocker ratio, and valve spring is on it? What kind of pushrods?

Interesting torque curve too. Looks like the torque starts to fall then comes back up a little. Never seen that on a 2X4 sheetmetal manifold deal before. Happens a lot with cast single 4 stuff with short and long runners. Makes me agree that the headers or ex size is not working well with your manifold runner lengths/taper.

airflowdevelop · Post by **airflowdevelop** » Thu Dec 29, 2005 12:28 am

Either you are measuring your fuel flow with a measuring cup, or your tuneup is mega-fragged (translation FUBAR)

aedcarburetors · Post by **aedcarburetors** » Thu Dec 29, 2005 3:33 am

found the problem today ...since we purchased the engine and car turnkey we put it on the pump to get a baseline out here..... its blown a head gasket between 5 and 6 ....it was like that when we recieved it as there was only 10HP between the 8 pulls that we did ..and it finally pulled in water on the last pull yesterday. we fixed the dyno cell exhaust puting the 6 inch right up to the end of the 4.5 collector .....it actually droped 10HP doing that ...

i was told the engine was freshened and had only dyno time but after pulling heads off the pistons look like they have done a season so shorts coming apart and i'll see what else awaits..