Dyno Vs.Drag Strip Testing

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pittsburghracer said:
Heck guys won’t even invest in a 300.00 weather station and without weather conditions how can you tell if what you did helped or hurt.
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I use this web site instead.

US Tracks « Air Density Online

Its free, and you can look up your track...updates are pretty regular (every 15-20 min I think), plus you can look at historical data which is pretty neat. Pull up an old time slip, check the date and time and find out what the DA was for that run. Pretty cool stuff.
 
justinp61 said:
Using speed it's down 31hp, ET it's down 51hp. I'm not sure how much loss there is driving the water pump, fan and alternator, plus header and ignition differences.
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And that makes perfect sense. You add in those variables and the dyno is pretty damn accurate.

Plus, the fact that you tune your stuff makes HUGE difference. Out here, in the NW, most guys don’t even know HOW to tune. So they just drive the stuff and it runs what it runs.
 
j par said:
My favorite one so far is it saves time at the track? Lol isn't that what we built them for?... LOL...View attachment 1715584066
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It’s a MASSIVE time saver.

Again, what does the dyno have to do with the track? A bunch of stuff I’ve had on the dyno never hit the track.


Why all this track crap keeps cropping up makes no sense. If you ever spend the day on the dyno, you’ll wonder why you didn’t do all these years.
 
yellow rose said:
It’s a MASSIVE time saver.

Again, what does the dyno have to do with the track? A bunch of stuff I’ve had on the dyno never hit the track.


Why all this track crap keeps cropping up makes no sense. If you ever spend the day on the dyno, you’ll wonder why you didn’t do all these years.
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I guess I have always been one that loved a challenge. I’m going to say my car is probably 85% track tuned before it hits the track. I don’t even test n tune with a new combo anymore. Two time trials and race.
 
flyfish said:
I use this web site instead.

US Tracks « Air Density Online

Its free, and you can look up your track...updates are pretty regular (every 15-20 min I think), plus you can look at historical data which is pretty neat. Pull up an old time slip, check the date and time and find out what the DA was for that run. Pretty cool stuff.
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Not close enough for me. I want my info from my weather station.
 
I have dynoed my last 5 engines ,sure its nice to see what kind of power it makes but it also finds problems. My last motor broke on the dyno, it was fixed no problem as damage wasn't extensive. What if it had broken at the track after all the time it takes to put the motor in and out of the car? I like the fact I can pretty much take the motor from the dyno and put it in the car as all the tuning, break in and valve adjustment is already finished and go racing. Test and Tunes are nice but in most cases you are lucky to get three runs in a day at my home track at times. Its also a good way to try different things such as I picked up 13 hp with a manifold change, tried different carb spacers, headers, timing, different size carb such as you would think my 408 would want a 950 it didn't my 750 was better etc. I have had my car 38 years with 6 different small block combos its nice to know the hp and torque of the motor and know how the car will react. The dyno was a great surprise for my last motor: I expected around 500-510 hp from my pump gas 408 I was real happy it made 539 but 52 more lbs. of torque over my previous 363 as a result I was able to go from a 4.88 gear to a 4.10 with E.T. and 60 ft. remaining the same. Track testing is good as i do that also but I like my motors dynoed ahead of time.

IMG_2725.JPG
 
How much is dyno time? My local track is now at $100 for five hours of test-n-tune. So, three laps at $33 bucks? Five laps for $20 each? ( up from thirty bucks a night, pre china flu. Was $20 just a few months before that.)
 
pittsburghracer said:
Heck guys won’t even invest in a 300.00 weather station and without weather conditions how can you tell if what you did helped or hurt.
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Some guys just want to go out once in a while and have some fun. Others just want a baseline and bracket race that’s great also. But if you want to keep improving what you have you need to make a investment. Most guys that just drive them on the street are never going to lift a wrench. Or worse never even have them checked out by a qualified mechanic. Seen way too many opps when their brake line breaks at cruise night. Please if you fall on the last category have your vehicle checked over. You think it is a bad night when you wreck your car just think how bad it can get when you run into someone else’s all original Hemi roadrunner!
 
sireland67 said:
A buddy of mine attends quite a few flash-light drags around here, they are close and cheap to participate in, but no times.
Closest drag strip is 3 hrs away
There is a local guy that set up a chassis dyno in his garage, he charges $40 for three pulls.
After the first pull, the first thing he said, "Your converter is wrong, you are driving thru it"
He still made 420 HP at the rear wheels, but immediately changed the converter, and it made a huge difference in how the car drove.
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Sounds to me as if that guy is worth more than $40 for three pulls.
 
There are a couple things that stick out in my mind about my dyno experience. The first is that with a 1" Super Sucker my engine picked up 13 hp. But more importantly the air fuel ratios from both banks came to within a couple hundredths of each other. before the install they were over a full point off. And on the last pull I hooked up the PCV valve, it was worth 3 hp. That stuff is hard to see at the track and unless I had been running dual o2 sensors I would've never known the fuel mixture were off bank to bank that much. Looking at the plugs would've had me scratching my head. LOL

The best part was the new friends I made, all Mopar guys and great people. The owner, Dale Meers and I actually knew a lot of the same people from years ago at dirt tracks and probably had crossed paths several times over the years. We all had lunch together and it was like going out with life long friends. Good times.

As I said in one of my other posts. I had a et goal when I started the build and had I not broke in and tuned the engine on the dyno to know it had the power to realize my goal I may have given up and never reached it. The dyno gave me a baseline to start from but it took a lot of work on small stuff to get where I wanted to go.

Guys like John who have their cars sorted out very well and have ran similar combos before probably already have a good idea where everything needs to be and may not benefit as much from the dyno time.

For me the time slip was the reward for the hard work to get there and the proof that my engine was making the steam it was supposed to, it backed up the dyno sheet. If I were a bracket racer it wouldn't matter I'd tune it to be consistent and leave it alone. The number on the time slip really wouldn't matter as long as the car could repeat it.

In the end for me the dyno was just another tool, like the O2 meter or timing light to help me achieve what I wanted. That time slip was the reward.
 
BVoelzke said:
I have dynoed my last 5 engines ,sure its nice to see what kind of power it makes but it also finds problems. My last motor broke on the dyno, it was fixed no problem as damage wasn't extensive. What if it had broken at the track after all the time it takes to put the motor in and out of the car? I like the fact I can pretty much take the motor from the dyno and put it in the car as all the tuning, break in and valve adjustment is already finished and go racing. Test and Tunes are nice but in most cases you are lucky to get three runs in a day at my home track at times. Its also a good way to try different things such as I picked up 13 hp with a manifold change, tried different carb spacers, headers, timing, different size carb such as you would think my 408 would want a 950 it didn't my 750 was better etc. I have had my car 38 years with 6 different small block combos its nice to know the hp and torque of the motor and know how the car will react. The dyno was a great surprise for my last motor: I expected around 500-510 hp from my pump gas 408 I was real happy it made 539 but 52 more lbs. of torque over my previous 363 as a result I was able to go from a 4.88 gear to a 4.10 with E.T. and 60 ft. remaining the same. Track testing is good as i do that also but I like my motors dynoed ahead of time.

View attachment 1715584180
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This is perfect for dyno test and tune. Most people just want a basic time and number. And really most people just can’t afford it. Just curious what was the dyno cost for this tuning session.
 
“This thread is worthless without a dollar amount for Dyno time”!! What did you pay and how much extra horsepower and torque did they find versus What you were able to extract on your own?
 
12many said:
“This thread is worthless without a dollar amount for Dyno time”!! What did you pay and how much extra horsepower and torque did they find versus What you were able to extract on your own?
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500-600 dollars. 15-18 horsepower. Lol
 
I think our local hot rod machine shop charges $2-300 for a session. I will pay next time just to have the sheet. Just for fun. Disappointed or not.


 
It cost me $400 plus the break in oil. My engine was on it for most of the day. Again, it was the best spent money on the build.
 
pittsburghracer said:
500-600 dollars. 15-18 horsepower. Lol
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So John, what would it cost the average person to build your nitrous heads up big block?

You're going to tune it how? $400 wouldn't be money well spent for a couple good tunes?
 
What about butt dyno’s? do those count? I’m sure there are a lot of good ones out there! Are skinny ones more accurate than big ones? there’s obviously a lot of sensitive ones that’s for sure! Then you got the ones that are full of it.......:eek:
 
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justinp61 said:
So John, what would it cost the average person to build your nitrous heads up big block?

You're going to tune it how? $400 wouldn't be money well spent for a couple good tunes?
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I don’t need no stinking Dyno. And I have no idea what it would cost someone to build as the last one I paid for was back in or around 1978. It’s in the car waiting for me
 
12many said:
What about butt dyno’s? do those count? I’m sure there are a lot of good ones out there! Are skinny ones more accurate than big ones? there’s obviously a lot of sensitive ones that’s for sure! Then you got the ones that are full of it.......:eek:
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Screenshot_20200710-070421.png
 
Rmoore said:
You are correct !! You make my point for me ! Thank you for explaining this to everyone. You are so right!! So take your car to the track an run it ! Running your car can make the dyno a liar ... your car may have a lot more horsepower than the dyno shows !! Or the track will show you don’t have as much as the dyno says !! Awesome response Sir !! I could not agree more !
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No..it doesnt make the dyno a liar, it makes your car NOT a race car...and basically a sponge that absorbs all the power before it get to the pavement.

A good chassis, well set up race car chassis is worth more than any 700 hp motor you could throw in it.
 
LOL.... so much wrong and things taken out of context. Ha! Trying to figure HP ratings using ET slip is just ballpark at best. And trying to use the dyno HP rating to figure the ET is just ballpark at best. If a guy swapped converters and dropped 4 tenths, how much HP did he gain??? << This example is why using ET slips to figure HP is skeptical at best.
 
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