FE Torque Curve

[blykins]

Not sure. You would think that the O2 sensors would be reading the results accurately, but I'm not sure.

I know that when we do dual carb engines, we lay the hood down on the distributor so that both carbs get a snoot full.

[vector1]

i would guess since they are only monitoring one carb, they half some of the data in the program, so double the a/f ratio, and v/e% and the air scfm.

[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?"

[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.

[blykins]

Originally Posted by blykins

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

Had a flat on the way home yesterday, so that put me behind the rest of the evening...didn't really have time to expound.

But here's my thoughts on this:

You don't cruise at 3000-3500. You cruise at 1800-2500. Dynos generally won't pull down that far, so if you're wanting a good realistic view of what's going on as you're going 60-70 mph down the highway, I don't think it would be easy or prudent to go there.

If I were an independent dyno operator, I would decline at someone's request to pull it down that far, even if I were able to. As I mentioned earlier, you don't always know what the compression ratio is, what the cam is, what the timing is, etc. You get an engine pushing 11:1 with a short cam, too much total timing, and a quick curve, and I think it would be rattle city if you tried to lug it at wide open throttle at low rpms.

A pull from 3500 will tell you everything you need to know, unless you're building an engine for your RV or dump truck.

[DanEC]

Originally Posted by blykins

A pull from 3500 will tell you everything you need to know, unless you're building an engine for your RV or dump truck.

I wish I had had the presence of mind to request a recorded pull from 3500 on my motor. I still think it's likely the chart recorder left a little peak torque back of 4200 rpm. With 9:1 compression and a fairly mild build I don't think it would have stressed it.

[AL427SBF]

Originally Posted by blykins

Had a flat on the way home yesterday, so that put me behind the rest of the evening...didn't really have time to expound.

But here's my thoughts on this:

You don't cruise at 3000-3500. You cruise at 1800-2500. Dynos generally won't pull down that far, so if you're wanting a good realistic view of what's going on as you're going 60-70 mph down the highway, I don't think it would be easy or prudent to go there.

If I were an independent dyno operator, I would decline at someone's request to pull it down that far, even if I were able to. As I mentioned earlier, you don't always know what the compression ratio is, what the cam is, what the timing is, etc. You get an engine pushing 11:1 with a short cam, too much total timing, and a quick curve, and I think it would be rattle city if you tried to lug it at wide open throttle at low rpms.

A pull from 3500 will tell you everything you need to know, unless you're building an engine for your RV or dump truck.

I guess we'll agree to disagree. Not all engine dyno's are created equal, nor are the latest chassis dyno's. Fortunately for me I'll have access to a Dynapack 4000 that bolts right up to the hubs and can provide a full load via calibrated EMF at any RPM you want. These guys are local and will be doing mine when the times comes, the vette vid shows just how clean a setup it actually is.
Dyno Services | Goodies Speed Shop - San Jose CA

[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.

[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

[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.

[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.

[GT350Mike]

Originally Posted by 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.

For a moment, I thought this was going to get really interesting. Glad to see a little friendly rivalry.

BTW Brent, thanks for the clutch/slave cylinder info!