Dyno'ed My 360..it's a pig..what next?

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RustyRatRod said:
Were you happy with how it ran before you saw some crappy dyno numbers? If so, screw the dyno.
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Yes, I'll agree with you there. It has good torque, and will easily roll out on the highway without downshifting. It's also very easy to bark my 10" M/T Street Radials even when I'm not trying. #-o It has snappy throttle response down low....which I will admit is what I wanted, and why we got the cam we did.

It's at WOT that it feels like it's not doing it's job, but the lean A/F explains some of that.

It'll get tuned, I'll see what I think, and go from there. Chances are just getting it running right "as built" will be sufficient to keep me happy. Unfortunately I do not have the pockets to throw a few grand at this "issue" when absolute numbers and trap times mean nothing to me.

On the plus side, I had planned to ditch the long tubes to get rid of the clearance problems...and now it looks like shorty headers aren't going to hurt me any, LOL.

Here is a video of the run....spliced the beginning and 2nd run together since people were chatting in foreground on the other run.

https://youtu.be/CyEqRbk_fLw
 
The thing you need to remember is a dyno is a tuning tool. No two are the same and the operator can skew numbers. Dyno's also require regular maintenance, so that alone can change numbers.
 
If you like how it runs, then I wouldn't worry what that dyno says. Get the AF ratio figured out and make sure the timing curve is optimum.
 
I didn't read all the posts but your combo runs exactly what the sum of it's parts says it should.

It is what it is. If you liked it before, leave it be.


99% of the keyboard warriors have never had their stuff on the dyno and guess what the HP is. Think of a 500 HP. 3400 lb car. Should run low 11's.

Not many of those actually running around.
 
I have to agree with Rusty, AbodyB and company. I do have a few points to add FWIW.
One key way to get Hp is to have a high revving engine. In other words, if your engine wasn't done at 4700, you'ld have much high hp numbers. That said - I had my car on a chassis dyno where somehow they got much lower curve than any of the other dynojets I've had it on, and it ran out of steam early. They made some other mistakes too, suggesting to me it was operator, not the car. Since I've driven the car/engine on the drag strip, I have a pretty good idea of how it pulls at the top - and one thing it doesn't do is drop power at the top!

Now as far as what to do. First, check the throttle to the accelerator pedal. The pedal floored needs to make the throttle fully open. If not, adjust until it does.
Tuning. Got to laugh. Same word, two different meanings. Your meaning - checking the plug gaps etc, to factory specs, is the norm in the automotive service world. In the hot roddng and racing world, it means making adjustments until it a given setup runs as good as you can get it. Your engine aint stock and you're looking for power, so this is the way people here intended it.

In that context, the AFR is showing much more than just lean. It showing a trend toward lean from mid to top. When the curve is not flat, then its probably not jetting. If you get to do it again- disconnect the secondaries. This will at least tell you whether the primaries or secondaries or both are not providing a flat AFR. I'll leave it there, since I'm not sure you want to get into carb tuning..but I think that's where the most improvement may be had.

There is some chance timing could use tuning too, but what you posted should be ballpark.
 
It'll get tuned, I'll see what I think, and go from there. Chances are just getting it running right "as built" will be sufficient to keep me happy. Unfortunately I do not have the pockets to throw a few grand at this "issue" when absolute numbers and trap times mean nothing to me.

This kinda tells me that everyone has been pi$$in in the wind with their advice.
 
You already have the Air Gap. I would address the heads. It sounds like your flow is poor. I have Comp's XE268 in my car with a 750 Eddy carb and some lightly worked J heads with 2.02s. I think you could easily hit 250 at the rear wheels without spending a bunch of money IF you can do your own work.
 
ebigga67 said:
It'll get tuned, I'll see what I think, and go from there. Chances are just getting it running right "as built" will be sufficient to keep me happy. Unfortunately I do not have the pockets to throw a few grand at this "issue" when absolute numbers and trap times mean nothing to me.

This kinda tells me that everyone has been pi$$in in the wind with their advice.
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^^^^^^^^^^^^^^^^YUP^^^^^^^^^^^^^^^

Prolly 20 HP in the tune up. That'll give you 200 HP to the wheels, about 220 crank HP.


Tell all the wizards at the car shows it has 450. How will they know? It's all good.
 
I swear. bad advice is a lot worse than no advice at all...:banghead:
 
frosty_the_punk said:
I swear. bad advice is a lot worse than no advice at all...:banghead:
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:LOL: Aint that the truth. Everyone looking for info has to do their own filtering and sorting of valid, relevent and baloney; And the free 'net is worse than books and magazines because there is no vetting process. Anyway....

Superdart, You did title this thread "..What Next?" IF you (and maybe your club buds) want to take your hobby in slightly different direction, Frosty's suggestion to get a logging wideband O2 setup with rpm is a good one. That, and time, will be your biggest expenses. :)

Maybe its not your thing,that's fine. You may find the challenges and process of performance tuning - the journey if you will - to be something you like doing. It's also an excuse to go the drag strip, which even if you don't care about the numbers (and to some degree you obviously do or you wouldn't have started this thread) can be an enjoyable evening. I know the last time I went it was a really enjoyable evening. Previous times (at different location) it wasn't so much. Find a nice strip and go when its not too busy - a muffler only "grudge night" or such. Take someone(s) who have some experience.

If you want to tune, you'll also have to do some reading up on carbs. Good basic info is in Chrysler's Master Technician Conference booklets - available on-line at imperialclub.org
More advanced information and help is at the racingfuelsystems forum and its pretty free of BS. There's a lot to learn but its rewarding and can be fun.

FABO Thread on WBO2 logging with comparison images to
dynojet's software. http://www.forabodiesonly.com/mopar/showthread.php?t=238682
 
Drag racing may not be your thing, but, I GUARANTEE that engine isn't happy with a 14:1+ AFR at full throttle at EITHER end of the pull. Your engine should make decent power to 5200-5300 range, I've had the same basic cam in the same build and it ran 102+ in the 1/4...

It DOES NOT need bigger valves, heads, camshaft or any other mechanical stuff other than getting the fuel curve squared away. That much of a mess in curve could be 50hp.

Pick your parts, pay your money.
 
ebigga67 said:
This kinda tells me that everyone has been pi$$in in the wind with their advice.
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Not necessarily...but I need to start somewhere. Spending time tuning to see what the current setup can really do BEFORE I go throwing money at parts makes more sense. With a proper tune I might be completely happy...or I may decide that I need to start giving Summit part of my paychecks for a while. I started this post thinking there was a defect/problem with the setup (aside from the A/F). Now I'm realizing there isn't anything "wrong" with it aside from not being an efficient power making setup. That doesn't make it a "bad" setup.....just not one that makes a ton of power.

Where I go from here will be dependent on how the car feels once it has some good fuel delivery.

harrisonm said:
You already have the Air Gap. I would address the heads. It sounds like your flow is poor. I have Comp's XE268 in my car with a 750 Eddy carb and some lightly worked J heads with 2.02s. I think you could easily hit 250 at the rear wheels without spending a bunch of money IF you can do your own work.
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Heads are probably one of the first places I'd make a change, if needed. I know people who are very good at porting, so I might port/re-valve what I have, or maybe go get some Edelbrocks and benefit from the weight savings.

yellow rose said:
Prolly 20 HP in the tune up. That'll give you 200 HP to the wheels, about 220 crank HP.
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I'm probably making more than 220 at the crank now.....but the A-518 is soaking it up like a sponge. :banghead: Not worrying about that.....at least I know it can take a beating.

frosty_the_punk said:
If you wanna screw around with getting the mixture right, save yourself a lot of time and headaches and get a wideband O2 sensor.
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Was thinking about a wideband....thanks for the link.


I do appreciate everyones input, and understand that people have different opinions on what they consider "good power". I will take all this under consideration. I am methodical in my troubleshooting. Start small, and work up from there.....
 
Do you have another carb you can swap over temporarily? Might be worth kitting a used 600 Holley or Edelbrock as a starting point.
 
Not necessarily...but I need to start somewhere. Spending time tuning to see what the current setup can really do BEFORE I go throwing money at parts makes more sense. With a proper tune I might be completely happy...or I may decide that I need to start giving Summit part of my paychecks for a while. I started this post thinking there was a defect/problem with the setup (aside from the A/F). Now I'm realizing there isn't anything "wrong" with it aside from not being an efficient power making setup. That doesn't make it a "bad" setup.....just not one that makes a ton of power.

Where I go from here will be dependent on how the car feels once it has some good fuel delivery.

Okay, I'll go back to my advice about taking it back to the dyno shop and let them tune it for you. Not to begrudge the previous tuner but as you say it's not efficient. I'd pay the dyno shop to get it as efficient as they can and live with the results before I would give Summit my paycheck. As stated before, you seemed happy until you found out what it actually made for HP. I'd drive it and enjoy it if I were you.
 
I use the old *** dyno, never lets me down. this is how it works, place a passenger in seat, floor it and run it through the gears, if your passenger is not holding on for his life, you need more power. I have never built a car or truck that failed that test,
just about broke my friends neck years ago. lol
 
crackedback said:
Drag racing may not be your thing, but, I GUARANTEE that engine isn't happy with a 14:1+ AFR at full throttle at EITHER end of the pull. Your engine should make decent power to 5200-5300 range, I've had the same basic cam in the same build and it ran 102+ in the 1/4...

It DOES NOT need bigger valves, heads, camshaft or any other mechanical stuff other than getting the fuel curve squared away. That much of a mess in curve could be 50hp.

Pick your parts, pay your money.
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X 2.

Tuning to optimize your fuel and ignition throughout the rev range isn't just about drag racing or getting the horsepower numbers for bragging rights. it WILL run better, get better mileage, sound better, live longer and make more hp AND torque to boot when tuned correctly. :burnout:
 
I'm going to reiterate that 576 actually are the worst flowing as cast heads,but are the best flowing portedfactory,although not production casting.
I believe Stan Weiss flow chart has the as cast flow #s.
 
I would not spend any money to swap parts until you optimize your current combination. Getting the AF dialed in along with the timing should pay good dividends. If it would make you feel any better, your car would have dyno'ed 40-50HP higher with a 904. versus the A518. The race track showed me swapping in a A500 in place of a 904 cost me 40 HP (4 MPH in the 1/4 mi). I bet a A518 takes more HP to turn then a A500.

HOT ROD did a dyno test on a '98 Dakota that was rated rated at 250 hp at 4,400 rpm and a whopping 345 lb-ft of torque at 3,200 rpm that demonstrates the losses associated with the A518/A500 trans:
"Our dyno test (see "Modern Muscle: Who's Jivin' Who?" May '98 ) showed that the R/T made 191 hp at the wheels."
 
m880 said:
I'm going to reiterate that 576 actually are the worst flowing as cast heads,but are the best flowing ported factory,although not production casting.
I believe Stan Weiss flow chart has the as cast flow #s.
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Duley noted...These might get some work done before I go to Eddy's...only because I know someone local who can do them without me shipping them out. He an old schooler who's been building engines as long as I've been alive.

sledger46 said:
I would not spend any money to swap parts until you optimize your current combination. Getting the AF dialed in along with the timing should pay good dividends. If it would make you feel any better, your car would have dyno'ed 40-50HP higher with a 904. versus the A518. The race track showed me swapping in a A500 in place of a 904 cost me 40 HP (4 MPH in the 1/4 mi). I bet a A518 takes more HP to turn then a A500.

HOT ROD did a dyno test on a '98 Dakota that was rated rated at 250 hp at 4,400 rpm and a whopping 345 lb-ft of torque at 3,200 rpm that demonstrates the losses associated with the A518/A500 trans:
"Our dyno test (see "Modern Muscle: Who's Jivin' Who?" May '98 ) showed that the R/T made 191 hp at the wheels."
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Yeah...I will say it was noticeably slower, until I swapped from 2.45s to 3.55s. I figured it would hurt when I did it, but didn't think it was that much loss. Oh well....lots of highways around here, so it's worth it.:cheers:
 
superdart said:
Interesting, but if there were a 140hp difference, my car would only read 40hp on a Mustang Dyno. :wack:
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Yup. Maybe interesting reading but it fails the math test early on. Power is proportional to rotational speed (or rpm) so the difference they attribute to method of testing should not be a simple number. My recollection is that these dynos use a load cell (rather than an rpm-time calc based on inertial mass). Also, for the record, its been a long time that many Dynojet models have the option of adding load. Load can be added as constant, or the drum held to a constant speed plus other options.

One advantage of inertia dynos is the ability to estimate drivetrain losses by doing a coast down test. The procedure is even in Dynojet manual I downloaded a number of years ago. Basically all of testing depends on how well the operator understands the equipment
 
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