The Real Truth About Dyno Sheets

[Bronc69]

I thought this would be best served here. Banks is a fantastic company that have been around a long-long time.
Excellent information here:

Sponsored

 

[ctandc]

Good info for those who haven't been exposed to dyno runs / dynos etc. Dyno runs are used by reputable tuners to first establish a baseline and then see the results of changes they make in real time, at the same time monitoring real time engine conditions such as spark knock, timing, air/fuel (via wideband O2 sensors) etc.

Dynos are also heavily used by aftermarket parts companies to show "gains" their product produced. Different dyno runs aren't even really that comparable for smaller number comparison, even using the same car / engine.

Software, type of dyno, smoothing / correction factor, humidity, temperature, testing conditions etc etc - there are so many variables it's ridiculous.

While it feels good to say "My car / truck / Bronco made XX hp over stock!" - Most times it doesn't really mean all that much.

I've personally seen HP variance of 20HP because of fuel quality in a high out put V8 engine - that's with the same car, same operator, same dyno, same weather etc.

Bronco owners should be more concerned - when it comes to tunes etc - with torque gains under the power curve. The easy way to think of it?

HP is what pushes you down the road once you're already moving.
Torque is what pulls you at low speed and from a start.

It's all about application. With daily driven vehicles, especially trucks - pulling larger tires, off-roading, towing - TORQUE in the low to mid RPM range is what you want. Unless you're making high speed desert runs.

It's why most people who tow large loads on a regular basis prefer diesels. Why? They don't make much HP, but they make tons of low to mid RPM range TORQUE. It's also why claims of aftermarket parts / tunes on vehicles like Broncos that claim "15HP gain" - are many times ridiculous.

You gained 15 HP. On paper that's great. But peak HP occurs at higher RPM and peak Torque occurs at lower RPM on most conventional internal combustion engines.

Also keep in mind almost all HP / Torque figures from auto manufacturers are numbers measured from the flywheel of the engine so they will ALWAYS be higher than what you see if you go get a dyno run done. Friction / drivetrain loss at work.

From everything I've seen the Bronco hits around 15% lost at the wheel from the flywheel.

 

[HBTFD]

I am amazed at how 20 hp at 5000 rpms motivates some to buy parts for a vehicle that is not raced.

 

[Bronc69]

It's all about the usable horsepower and torque.
I've argued with guys for years over chassis dyno graphs and the numbers some "tuners" are getting.
I love all the technical details given in the video. This should help a ton of people make much better decisions regarding parts.

 

[HotdogThud]

I also love it when people post 'crank hp'.

Crank HP is the equivalent of measuring your dick from behind your balls. Sure it's there, but you're not using it.

 

[FoxFour281]

I am amazed at how 20 hp at 5000 rpms motivates some to buy parts for a vehicle that is not raced.

For real... If this was a mustang forum it would be different.

 

[HBTFD]

For real... If this was a mustang forum it would be different.

I wish would Ford put a diesel in a bronco. Then the programmers could make usable power. My 6.7 tune is wonderful.

 

[V1Rotate]

I am amazed at how 20 hp at 5000 rpms motivates some to buy parts for a vehicle that is not raced.

Don’t tell that to the K&N folks… they‘re getting SERIOUS gainzzz

 

[mcinfantry]

I’ve always said diesels have useable torque below 1000 rpm

even argued on a few posts about it

I know I canlet the clutch out on a diesel below 1000 and not stall and gas engines do

I also realize a few other variables but I’ve done a lot with 105hp and 265tq in a 6000lb vehicle

 

[Bronc69]

I wish would Ford put a diesel in a bronco. Then the programmers could make usable power. My 6.7 tune is wonderful.

Engine swap?

Unfortunately, looks like everything is going to buzz instead of churn.
Jeep has the EcoDiesel and the 4Xe, not sure how the EcoDiesel sells. I suspect Ford would go the hybrid route.
Diesels are fantastic for off-road situations. Plus, you get better fuel mileage.
Hybrid will only get you so far before the charge is gone and you're relying on the gas engine anyway. EV power only for an off-road vehicle - I'm not sure how that's going to work. Once you're out of charge, then what?

 

[HBTFD]

Engine swap?

Unfortunately, looks like everything is going to buzz instead of churn.
Jeep has the EcoDiesel and the 4Xe, not sure how the EcoDiesel sells. I suspect Ford would go the hybrid route.
Diesels are fantastic for off-road situations. Plus, you get better fuel mileage.
Hybrid will only get you so far before the charge is gone and you're relying on the gas engine anyway. EV power only for an off-road vehicle - I'm not sure how that's going to work. Once you're out of charge, then what?

I was hoping for the diesel option available in the non US rangers.

 

[ctandc]

I’ve always said diesels have useable torque below 1000 rpm

even argued on a few posts about it

I know I canlet the clutch out on a diesel below 1000 and not stall and gas engines do

I also realize a few other variables but I’ve done a lot with 105hp and 265tq in a 6000lb vehicle

Gearing (transmission and differential) is the biggest difference for letting the clutch out at low RPM w/o stall. I had a 1st Gen K5 Blazer years ago with a 454 and a granny geared 4 speed with 4.56 diffs and 38" tires. I could literally let the clutch out at idle and it wouldn't stall.....it would just creep down the the trail.

 

[mcinfantry]

Gearing (transmission and differential) is the biggest difference for letting the clutch out at low RPM w/o stall. I had a 1st Gen K5 Blazer years ago with a 454 and a granny geared 4 speed with 4.56 diffs and 38" tires. I could literally let the clutch out at idle and it wouldn't stall.....it would just creep down the the trail.

And I’ve done a 4bt Cummins swap in a few k5’s

and I can tell you that all things being equal (4bt vs big and small block)
There’s literally no comparison

also nv4500 and 4.56, 38” tires
Also 4l80e 4.88 and 38” tires

 

[ctandc]

And I’ve done a 4bt Cummins swap in a few k5’s

and I can tell you that all things being equal (4bt vs big and small block)
There’s literally no comparison

also nv4500 and 4.56, 38” tires
Also 4l80e 4.88 and 38” tires

I didn't disagree with diesels making more torque down low. You mentioned stalling a manual trans out at idle / low rpms. That's what I replied about. I relayed one of the setups I'd had that was pretty much impossible to stall out.

And honestly? With modern computer setups, it is almost impossible to stall out a manual transmission vehicle made in the last few years because of computer controls.

 

[Bronc69]

I didn't disagree with diesels making more torque down low. You mentioned stalling a manual trans out at idle / low rpms. That's what I replied about. I relayed one of the setups I'd had that was pretty much impossible to stall out.

And honestly? With modern computer setups, it is almost impossible to stall out a manual transmission vehicle made in the last few years because of computer controls.

I had a 2000 VW GL with the 2L gas engine. If you let the clutch out slow, it would just go. The only way you'd stall it is if you left the clutch out too quickly. Give it slight throttle and it was basically zero slipping of the clutch. Lasted 240K and still held strong when I traded it in.

Sponsored