FE Torque Curve

[ERA Chas]

Originally Posted by DanEC

Chas may have that right.

Naaah-I'm just another pretty face Dan....

[AL427SBF]

Originally Posted by blykins

It's a reasonable set of numbers. Some dynos operate differently than others and a peak torque curve there is reasonable and realistic.

Keep in mind that you can't always pull an engine down that low, and most of the time it's not warranted, nor is it safe to do so. A wide open throttle pull at 2000-2500 can induce detonation and modern performance engines with larger heads and cams are not meant to have their guts pulled out at such a low rpm. You would see that kind of operation in a dump truck engine, which is meant to be fully loaded not too far off of idle....with compression ratios, dynamic compression ratios, piston design, ring gap, etc., to handle that kind of load and heat.

To make a long story short, I wouldn't advise asking a dyno operator to pull one down that far....

A reasonable starting point is 3500-4000. A dyno is more for determining issues with the engine, general A/F curves, and peak horsepower/torque numbers. You can't drive a dyno, and the poster that made the comment that everything changes once the engine is in the car, is correct. Different air cleaners, different headers, etc. make differences. While I'm ranting, I'll also point out that different ignition boxes (even of the same brand) will give different timing settings, so be sure and double check the timing once it's in the car and running.

I may move up to 3K then, still want to know what the power is where it will be driven - also talking chassis dyno.

[blykins]

You won't be driving it at WOT at lower rpms, so I don't understand that line of logic...

I would still use extreme caution when pulling an engine down that low with a full load on it. A chassis dyno is just as hard if you pull it down in 4th gear and open it up.

I would be concerned about A/F ratios and throttle response at street driving RPMs, but how much WOT throttle power it makes there is not useful.

[Barry_R]

We generally do our WOT pulls from 2500 or 3000 on up. No real reason not to - sometimes the 2500 is hard to grab on a bigger or torque oriented engine so I have gone to 3000 as something of a standard. Not that unusual to hammer the throttle from a 60or 70 MPH freeway cruise without downshifting.

My DTS does not monitor inlet air volume, and I have become pretty reliant upon O2 sensor readings for fuel tuning. You can usually hear it when things are going well or wrong, and should spend the time chasing the power data - its rarely a wrong move when power is going up no matter what the "numbers" are.

[blykins]

I suppose I wouldn't mind to pull from 3000 if I knew who put the engine together and what the specs were. An unknown engine from an unknown builder, with unknown or miscalculated compression ratios would scare me.

I dyno'd a Boss 9 engine down at Kaase's shop, and his dyno operator refused to start the pull from 2500 at my customer's request, just for the same reasons.

I don't see many people asking, "Wow, nice engine, how much power did it make at 2200?"

[Barry_R]

My builds, my shop, my guys, my dyno
If it's going to break I want it to happen in my house.
If I can't kill it nobody else should be able to...although I've run into a couple guys that could break a bowling ball in a sandbox...

This is a torque curve...

Still working on it - a bit rich downstairs. But down to small stuff at WOT.

This pull was open loop. I usually try to get the map close enough that the O2 correction percentage numbers are small - then try an open loop pull to verify the work. O2 corrections should be just that - corrections - and not relied on for the tune itself.

Stopped testing 'cuz we were running low on gas - check the fuel psi. Should have waited a few more minutes on water temp to come up 10 degrees more - I let it cool between efforts and I was getting anxious knowing our fuel situation.

The other A/F is on the EFI system computer - so only one side shows here.

[fordracing65]

Nice dyno chart Barry, what cam specs were used for that one???

[blykins]

138° water temp makes for some good horsepower numbers.... I bet the oil was nice and hot too.

I'm trying to find the dyno sheet of the 482 I did that made 636 lb-ft....or the sheet for the Boss 529 that had 700.

[Barry_R]

If you ever get the chance you are welcome to bring one of your engines up here to dyno and compare to your local guy. Free (you buy gas and lunch). It would be good data for all of us to have.

Having done the EMC deal for a few years I know that many dyno installations give different numbers, and that it has nothing to do with the intentions of the builder or operator - but more to do with room venting, exhaust layout, and physical hookups. I've compared mine to several local pumps, as well as the ones at the contest in Ohio - but more info is always good for everybody.

[ERA Chas]

Love it when builders share...

[blykins]

I wish you were closer Barry....I'd love to. Maybe some day...

The 636 lb-ft deal was a combo that I stumbled across....sometimes I get to experimentin' and I run across something that raises an eyebrow. Horsepower was just about 575 on this one, but torque was 636. Nothing shabby about 1.3 lb-ft /ci.

I sent the dyno sheet with the customer on that one, but I sent him an email to see if he would scan it and send it to me. Only issue is that he's in France....

Here's a 529ci BBF that I dyno'd down at Kaase's shop.

[DAVID GAGNARD]

Originally Posted by Barry_R

If you ever get the chance you are welcome to bring one of your engines up here to dyno and compare to your local guy. Free (you buy gas and lunch). It would be good data for all of us to have.

Having done the EMC deal for a few years I know that many dyno installations give different numbers, and that it has nothing to do with the intentions of the builder or operator - but more to do with room venting, exhaust layout, and physical hookups. I've compared mine to several local pumps, as well as the ones at the contest in Ohio - but more info is always good for everybody.

I'm looking at my last dyno session and all the pulls started at 3500 rpms.....That part I understand,looking the water temp,it stayed between 145 and 150......
looking at your dyno sheet,your water temp was in the 138 to 145 range,any particular reason for these water temps vs. running the water temp at 180 degrees,more closely to the "normal" operating water temp.???
Just curious.....

David

[blykins]

Just so everyone knows....I was just ribbing on Barry. In no way was I accusing him of padding his numbers. He and I have had offline email conversations about dyno results, based on the numbers shown from other builders.

Barry is one of the builders that I can joke around with and give a hard time....some of the others are ego-centric.

[Barry_R]

Originally Posted by DAVID GAGNARD

I'm looking at my last dyno session and all the pulls started at 3500 rpms.....That part I understand,looking the water temp,it stayed between 145 and 150......
looking at your dyno sheet,your water temp was in the 138 to 145 range,any particular reason for these water temps vs. running the water temp at 180 degrees,more closely to the "normal" operating water temp.???
Just curious.....

David

I normally run the pulls at around 160 water and oil. Its really a habit from the EMC rulebook, where the 160s are the required minimums and I set the thermostat on the cooling tower to that level. The water cools pretty fast when the engine's off - I have 1500 gallons in a vertical tank behind the back wall. Normally I'll run it for a while under moderate loads to build temp. On this particular pull I was re-lighting it after checking valve adjustments & plugs and realized that I was getting darn low on gas - so I just smacked it as soon as I felt comfortable enough. I happened to have it nearby to scan 'cuz it was the last one of the evening...

Brett can confirm seeing some Hollywood numbers on some sites where water was at 110 or less...

[ERA Chas]

See gang?? Engine builders aren't afraid to start 'em and run 'em hard cold-blooded.
They got no stinkin' covered-up url coolers.....
Actually NO coolers.

[blykins]

Just as long as oil temp is up....water temp is a little different.

[AL427SBF]

Originally Posted by Barry_R

We generally do our WOT pulls from 2500 or 3000 on up. No real reason not to - sometimes the 2500 is hard to grab on a bigger or torque oriented engine so I have gone to 3000 as something of a standard. Not that unusual to hammer the throttle from a 60or 70 MPH freeway cruise without downshifting.

My DTS does not monitor inlet air volume, and I have become pretty reliant upon O2 sensor readings for fuel tuning. You can usually hear it when things are going well or wrong, and should spend the time chasing the power data - its rarely a wrong move when power is going up no matter what the "numbers" are.

zackly Barry

[blykins]

I wish that statement could be made for all applications...but it can't.

[Dwight]

I don't understand

do you get better hp number with the water temp low?

Dwight

[undy]

Originally Posted by Dwight

I don't understand

do you get better hp number with the water temp low?

Dwight

Colder water = colder heads and intake. All that equates to a colder air intake charge. Colder air is denser and contains more oxygen per given CFM. More oxygen = more HP.