Dyno LB/H fuel

How does a Super Flow 901 dyno get the LB /H fuel consumption, is it just a calculation from the AFR & the CFM flow meter, or does it have a actual fuel flow meter ? Thanks, Charlie

A Flow meter determines volume.
An entered specific gravity figure and a fuel temp measurement allows for a volume/weight calculation in the software.

Fuel flow is displayed in lbs/hr(I’ve never looked, but you can probably display it another way if using WinDyn software)...... bsfc is calculated from observed uncorrected hp and measured fuel flow.

There should be a fuel flow turbine on the dyno. You can double check the flow turbine calibration with a gas can, a scale and a stop watch.

The flow turbine might not get used on EFI engines since it might be capable of handling high pressure. Most EFI systems have a built in flow meter so it doesn't matter. EFI systems have a lot of built in sensors which makes it much easier on the dyno.

Thanks Dwayne & Andy, a friend of mine has a race car I am helping him with, the CORRECTED #'s are very high, using the BSFC & LB/H fuel to get the uncorrected HP is much closer to the times that the car runs at the track, he is VERY disappointed, its a 500 cid Pontiac in a 78 Z28.

Yeah it can happen that way. If you know the date and location of the dyno test you can look up the local weather and figure out what the correction factor should've been. Then compare that to what the dyno shop used. Also check the inlet air temp if that is on the dyno sheet. Sometimes the shop will have the inlet air temp sensor located to close to the engine so the temp will be higher which then provides a bigger correction factor. The inlet air temp should be close to the outside air temp or a few degrees warmer. Dyno numbers are fairly easy to verify if you know what to look for.

Pretty simple really.......

You don’t race in corrected air....... and they don’t hand out corrected time slips.

If you tested on a day when there’s 10%+ correction...... that’s 10%+ you don’t have at the track.

If you had 500hp uncorrected on the dyno, and similar air at the track....... you’ll get 500hp performance....... and often...... minus whatever losses you incurred by having the motor in the car vs the dyno(drivetrain parasitic losses, under hood air, mufflers, crank driven cooling fan, etc).

If the dyno correction factors are high(which I’m sure they often are in Texas)...... those corrected numbers are just “pie in the sky”....... unless you can find some “standard day” air(60*, 29.92” baro, zero humidity) to race in.

I like to use 10% for a typical bracket car........ as a starting point.

Take the corrected power, knock 10% off...... plug that into the Moroso chart.

If the dyno correction is over 10%, I’d probably use something like 5% more than whatever the correction was, and plug that into the Moroso chart.

FWIW, I feel like the most productive way to try and tune on the dyno is to do it in similar weather to what you race in.

They used STP correction instead of SAE

Uncorrected

633.5hp@6000...... so......damn close to 10% correction.

Plus that pull is done with water temps that are going to be pretty hard to duplicate at the track.
And, depending on the combo and the tune...... that could easily be another 10-20hp you wouldn’t have in the car.

The pulls, and tuning should be done at the actual operating water temps.

I can see where the ET’s would coincide with numbers closer to 580-600hp.

Dang........ that air temp is pretty unfriendly.

If you have the whole dyno sheet there should be a correction factor on there. See if they used the correct correction factor. Maybe they did but the weather was really bad like Dwayne said. If that is the case then it is what it is. If they used the wrong correction factor then that is a different clue.

The real question is what are you trying to do? Are you trying to tune the car or trying to verify the dyno numbers? Do you want to confirm the dyno is working properly or focus on tuning the car?

I agree, the water temp numbers are either wrong or just stupid. The average bracket engine should not be run on a dyno at 110 degrees. Maybe a pro type race engine that is designed to run at 100 degrees but a normal engine should not be pulled when cold. The temp sensor is either wrong or else the shop was trying to fudge the numbers. I'm not sure which. A typical bracket car will go down the track with the engine at 160 or 180 so that is how it should be tuned and tested. We'll dyno boat motors at a lower temp since they pick up cold water from the lake but we never test car engines that cold.

Your friend may need to work on the chassis and drivetrain to make the car faster with the motor the way it is, what do the time slips and spark plugs look like?
On the BSFC it looks a little rich, especially above 5000 RPM, maybe try leaning it down a smidge to see if the MPH picks up or not
If it does and the 60 ft. get worst then traction maybe limiting the cars times
Torque converters in a race car can really hold the car back, compare his time slips to other similar cars at the track during the same time frame to see if that will help or not
I've also seen fuel delivery systems limit cars that the owners didn't thank it was, can you fatten the jetting up enough to slow the 1/4 MPH down? If not fix that next
How heavy is the car and what is it running ET and MPH on what length tracks?

Air temp of 102 is hot. Was it really that hot that day or did they move the sensor over close to the headers? That is why the correction factor is so high.

And I'd like to know how the water temp was only 110 when the air temp was 102? That doesn't really make sense.

His now race car is no faster than his 525 hp street car 1978 Trans Am, he was thinking a low 10 car, in good air its been 10.8 @ 124, 3600 lb race weight , when we rent the track again we will do some tuning, we put a looser converter in it, will also work on my Charger when we go.

Yes that is a typical summer day here in Southeast Texas

Car performance and dyno power are two totally different things. Some cars can put the power to the ground but most can't. You have to figure out what problem you are trying to solve.

I’ll often do a low water temp pull at the end of the session for the “hero pull”.

Here’s an example of what I see as fairly typical.......
Corrected power- 652hp
Uncorrected power- 632hp
Moroso chart power based on actual weight/mph at track- 605hp

I have a few customers who have the numbers closer than that....... but frankly, most are worse.

Okay, if the air temp was 102 then a 10% correction factor is very realistic, maybe even low. But the water temp of 110 degrees doesn't make any sense. There is zero chance that a bracket car cooling system will operate at 110 degrees when the air temp is 102. He will be lucky to run that engine at anything less than 180 degrees when it is that hot outside. Either the temp gauge on the dyno was broken or the dyno operator was trying to fudge the numbers. I don't know which but it doesn't make any sense. 80 degrees of engine temp can make a big difference. How hot does the engine run at the track?

That does seem correct, it has a full 3 1/2 exhaust, air filter, clutch fan, it was dead hooking, 1.75 60ft, we did a converter change, installed electric fans, our track will open back up at the end of this month, he said to me WTH your heavy a$$ street car Charger MPH is about the same as this car.

185-195

An observation........

The VE numbers look way too high.

And......

It’s using too much fuel for that amount of power.

When the air turbine shows too much air flow it makes the a/r ratio look lean.
I suspect the jetting decisions were based on looking at the a/f ratio numbers(as opposed to tuning for power)...... which I believe would have been erroneous.

Put an A/F gauge in the car........ I think it will confirm it’s rich.

IF...... the air flow numbers are correct....... you’re just blowing the air(and fuel) right through the motor without getting any work out of it.


.

Its all set up now with a afr,driveshaft rpm,ect , data on a Data logger

Thanks Everyone, even though its a non Mopar, I will let y'all know the outcome , Pontiac are right behind my love for Mopars

That does seem correct, it has a full 3 1/2 exhaust, air filter, clutch fan, it was dead hooking, 1.75 60ft, we did a converter change, installed electric fans, our track will open back up at the end of this month, he said to me WTH your heavy a$$ street car Charger MPH is about the same as this car. [/quote]
That ET with those 60 ft. times are no where near the best on the 60 ft. times
I think it should run mid to high 1.40 to low 1.50 60 ft. times at 10.80 in the 1/4 mile
Thinking back over my racing at the track, I've seen a gain of .15 ET and .4 MPH in the 1/4 mile when I pick the 60 ft. times up by .10
It may be the converter holding you back now
What brand and size is it?

That ET with those 60 ft. times are no where near the best on the 60 ft. times
I think it should run high 1.40 to low 1.50 at 10.80 in the 1/4 mile
Thinking back over my racing at the track, I've seen a gain of .15 ET and .4 MPH in the 1/4 mile when I pick the 60 ft. times up by .10
It may be the converter holding you back now
What brand and size is it? [/quote]

We changed the vert, to a much looser one, have not made a pass yet, hope to at the end of this month

What was the A/F ratio on the dyno(it’s not on the sheet) vs in car?

A comparison......
Your sheet -
6000rpm - 633.2hp - 317.5lbs/hr - bsfc .501 - 889cfm

A sheet I have here -
6000rpm - 634.9hp - 278.0lbs/hr - bsfc .438 - 801cfm

Granted, the crappier weather there would have this motor making less uncorrected hp at the same rpm....... but then the fuel and air flow would also be lower.

I’m just saying....... from what I see...... there should be some ET left in the tuning.

Looks like it should be running a converter in the 5000 range.

124@3600 shows 530hp........... so...... not too good.

What size is the motor..... compression ratio?

There could easily be 30hp in the water temp alone going from 110 to 195.

Its a 8" converter that was built from the dyno sheet LOL!!! it is WAY to tight, imagine that,,,,, on the data log 4000 rpm flash, we put a converter in it that would flash 5200 that came out of his steet car, we will see.

I dont have the AFR from the dyno

Do you know the cam specs?
Cubes?
Stroke?
CR?
Carb?
Intake?
Heads?
Header size?(same headers used on the dyno?)

Last but not least.......

Checked for full throttle?

505 Pontiac, ported Ede heads, roller cam, Victor intake, 1150 carb, 2” headers......

690hp uncorrected....... look at the fuel flow.

Solidly into the 9’s at 3600lbs.

Yes on the full throttle, my pet peeve
not sure on the bore & stroke combo.
500 cid
carb is a 1.560 ven,downleg 4150
Edel SP victor intake
ported edel old style heads 300 ish cfm on my bench
2" headers same headers
Cam. 268, 278 , .650 solid roller
11.5 com

FYI the "water out" temp is the water temp coming out of the brake, not the engine temp. At least that's the way it is on my superflow dyno. Not really sure why you would have that on the 1st page. Also a 1.08-1.10 is pretty normal correction factor.
to the OP did the dyno operator give you a "customer data pack"?


Joe

I will have to ask about the data pack ?

I have used 4 different sf-901’s.
On all 4 of those the temp probe that’s in the cooling tower next to the water hose coming from the engine was plugged into the “water out” receptacle on the engine stand.
(Edit...... I forgot about 1..... so it’s been that way on the 5 I’ve used)

In the pre-WinDyn days, the channel order was not user configurable........ and “water out” was on the first page, right next to the other basic temps.

With WinDyn you could simply rename it to whatever you wanted.

110 for water temp coming out of the brake makes sense. Having it on the first page doesn't since nobody really cares about that number except the dyno operator. I do agree that that is probably the explanation though since I can't see how the water coming out of the engine was actually 110 degrees on a 102 degree day.

I also agree that the VE numbers were way too high which indicates perhaps an issue with the air turbine. Wide band info during the dyno pull would've been useful. If that wasn't available then a plug check should've been done. I agree that the engine was probably fat on the dyno.

Based on the specs that engine should not have any trouble making more than 600 hp when it is properly tuned. If it was my engine I'd be shooting for 650hp with an engine like that. 700 hp if I ported the intake and used a Dominator.

I don’t know if the dyno used for that test was a 901 or a 902, and I have no experience with a 902.

But, on the 901’s I’ve used...... the temp probe connections get plugged into receptacles on the engine stand, that are already labeled, and coincide with a particular “channel”.

It doesn’t matter which probe you plugged into the “water out” receptacle...... whether it was really air temp, fuel temp, oil temp....... whatever it was....... it was going to be on the sheet in the “water out” column.

As I said, in WinDyn you could put it on any page you like, and call it whatever you want.

With the test in question, It seems pretty obvious to me........ you’d like to know what the water temp of the motor is for testing....... so if it’s there on the page with the other normal testing data...... it’s the engine coolant temp.

Many dyno operators run on town water instead of having a storage tank........ and in that type of system, there would be no problem having the engine being tested at a water temp as low as 110*.

On the left, are the two rows of holes for electrical connections.
The bottom row is where the temp probes get plugged in. The plugs are like old school headphone jacks.
They’re marked as “cat”, “water in”, “water out”, “oil in”, “oil out”, “fuel”, etc....... and there is a corresponding channel, and column on the print out for each.

First pic off a sheet from the dyno I’ve been using for 23 years.

Second pic is from another friends 901.

The “water out” is the coolant temp.

Obviously, Charlie could just call the dyno shop and ask what the “water out” column is displaying on that sheet.

I going to call them Monday, the dyno is at Westside performance, they are part of S.A.M.

If they aren’t using that column for coolant temp...... then ask them what the coolant temp was.

As long as they stored the tests, and there was a probe installed somewhere to take the readings...... and plugged in...... they should have it.

There are multiple pages of various data collected for each pull.

10-4
Thanks

You might also ask if they have a page that shows the A/F ratio.

The air and fuel flow have been collected....... there just isn’t a column displaying it on either of those two pages you posted.

will do

The "data pack" allows them to give you all the data and a wyndyn viewer in a exe file you can install on your computer. At the very least they can export each run to a CVS file so you can put all the data into a spread sheet.

you guys are probably right about the "water out" on a 901. My dyno is a SF powermark and the water out is from the brake and engine temp is from the cooling tower.


Joe

Having the coolant temp labeled as “water out” with WinDyn is just probably left over from pre-WinDyn days, when it was absolutely referring to coolant temp.

When we changed the system here from the MS-DOS format to WinDyn, there are already preconfigured pages and screens you can use if you like.
The headings on the temperatures and pressures page used the same terminology as the old DOS format....... so “WatOut” for engine coolant temp.

I rearranged the channel order to something we liked better, and never bothered to rename that column.
I see some guys with newer systems are calling it something like “CoolOu”....... which is probably the default terminology from SF now.

After looking at a data sheet, I have come to the conclusion the i have CRS syndrome. These are the default names on my powermark.

The first all out custom built drag race 8.0 inch converter I was involved with was from Art Carr, it slowed the 1968 hemi GTX down right at .3 ET and 3 to 4 MPH in the 1/4 mile from the stock 11.0 inch street Hemi converter, his was a real piece of chit
We, I, took it back 4 times for him to fix it(it had broke on the second run the first time we got it ) and I think he finally swap another one of his customers 069J B&M converter with us That picked the car up around .4 ET and didn't lose much MPH from the stock OEM 11 inch Street Hemi converter
I've had other horrible race converters from companies like Art Carr, GER and some other I won't add onto this now.
My main message is a good converter is absolutely needed for the car to 60 Ft. and MPH well

For this ? I was going to start a new Thread, but this all goes together , If you have a Carb that is square [barrels the same size] and it is jetted CORRECT front & rear ,it should not matter power valve or not, The question is, Should the A & B fuel flow be the same on the dyno, I see a lot that have WAY different amounts. seems like if the carb is set up properly they would be the same When I tune a carb I disconnect the rear & tune the front with a wide band & then hook up the rear & tune the rear

It’s one of those “in a perfect world” scenarios.......that yes, front and rear fuel flow on a square bore carb with equal sized venturi on all 4 barrels would be equal.

But many times it isn’t all that practical...... especially on something that gets driven on the street.

Often times after you get the primary side really dialed in for low speed and part throttle operation..... having the same jet/air bleed combo on the secondaries leaves the wot a/f ratio not where it should be, and/or not making the best power.
So, the secondary side ends up getting the final adjustments for wot operation....... and you’ll often end up with different fuel flow on the two ends.

If all the circuits are operating correctly...... you should be able to end up with a situation where there isn’t a big discrepancy between front and rear.

Keep in mind, not all carbs are “square”.
There are many carbs out there with different sized venturi between the primary and secondary........ and those would rarely see equal fuel flow from both ends(why would they?).

Thanks D wayne , I found when I was still running a carb, jetting down the pri jet to get the cruise light throttle AFR good & then increase the PVR size to get the WOT AFR on the primary where I want it works great, Thanks again for the GREAT info that you so freely give out. This imbalance of fuel volume could also look like a bad fuel distribution intake manifold.

From my experience, that's a bit too much carb at that hp level based on 900+ hp cars/trucks running 1150's and bigger......are there skirted banjos in it and how big if so....

Thanks for all the help on this, sorry it took so long to get back to Y'all, I forgot about this thread,,,,, OOOOOOOPSSS
We put a known good converter out of his Trans AM that is much looser in the Camaro just for testing, also took the carb that has the ventures that can be changed OFF & put the Smaller venturi 900cfm carb on it & on the 1st pass it went 10.45 @ 129 DA was 1700ft, pulled the air filter assembly off & it went 10.35 @ 132 then we went home. after looking at the Datalog we now can order a custom torque converter,,, Thanks again EVERYONE .

What does the car weigh?

This is what it did before we made all the Changes
10.8 @ 124, 3600 lb race weight -100 da

I was more interested to see what it weighs now that it’s going faster.

If it’s still around 3600lbs, 132mph shows 635hp on the Moroso chart.

Thats pretty close to the uncorrected dyno numbers.........and in this case, is also about 90% of the corrected numbers, so that formula seems to work out reasonably well for this combo.

Yes it is still 3600 lbs, I forgot to mention , we also put a vacuum pump on it, pulling about 4in IIRC , also this has all been done with a full 3.5 exhaust & Tail pipes

The performance of the car improved enough so that the dyno power numbers at least make some sense now.

If you have faith in the dyno numbers, and the car doesn’t run like it should....... you know where not to spend the time and effort trying to get it sorted out.

You said the car now has a data logger...... what does the a/f ratio look like going down the track?

it was in the low 12's , the 60ft was 1.547,,,,, still leaving soft IMO
330 4.304
1/8 6.637 @105.32
1/4 10.35 @ 132.56

Yes.......60’ is still a bit soft for that ET.
Should be close to a tenth better....... but you made some nice gains for sure

Thanks for the input Dwayne