Dyno Dumbfoundedness

KStromberg

KStromberg

VIII looking for 8s
Well, Saturday I had the opportunity to get the Mark VIII on the dyno for the very first time. It has never been dynoed when it was stock, but here you have it.

DynoSheet.jpg


We did two pulls on the car. This was the second pull which was better than the first but nevertheless very depressing numbers! Maybe I am in the learning stages here, but I was awe struck that the numbers were this low.:eek: We noticed that there was some timing being pulled up top that needs to be addressed by the tuner as you can see towards the end of the graph there at about 5800 up until rev limiter on the pull.

So, fellow Mark VIII nuts, help me understand this. With a calculated drivetrain loss of 20%, this pull we did would put me at 291.3 hp at the crank. These cars are rated 290 hp stock. So are you telling me that the Mark VIII is overrated? And get this, my two CVN buddies with Vics I have ran against several times. Dan with 276rwhp will run door to door with me but I will pull on him more up top. Hard to say now since I have the MTs. I think I would actually pull on him much quicker now especially off the line. Russ has 289rwhp with weight reduction (3650#) and I will run door to door with him all the way up to 95mph where he will start crawling away from me thanks to the Edelbrock Victor Jr. Intake that he just put on this spring. I just really don't get it at all. None of it makes sense. Maybe the 3800 stall and 4.10s are what gives me the "feel" of more horsies?
 
Looks about right. You'll also be suprised if you ever actually take it to a track. All that street racing doesn't mean much, too many variables.
 
Here is my sheet from way back in the day. I believe the car was stock except for the dyno tune, cat back exhaust, and maybe a cone air filter. I agree with DLF, looks ok to me. :)



 
i believe taller gears may give you lower numbers. also too many variables to compare dyno numbers to other dyno numbers on different days.
Also when i had mine dynoed we only pulled in 2nd gear as well because i had the stock drive shaft. So that gave slightly lower numbers.
A see a dyno just as a tuning tool the real test is at the track.


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moved the chart to photo bucket, web shots sucks for embedding image.


lincoln-dyno.jpg


steve said:
i believe taller gears may give you lower numbers. also too many variables to compare dyno numbers to other dyno numbers on different days.
Also when i had mine dynoed we only pulled in 2nd gear as well because i had the stock drive shaft. So that gave slightly lower numbers.
A see a dyno just as a tuning tool the real test is at the track.
Click to expand...
 
One thing that is confusing to me is why my torque numbers were lower than my hp numbers. Both of the dyno sheets you guys have posted for your cars show a higher torque number. My sheet shows just the opposite.

One thing to be noted is that the exhaust is straight from the headers with an x-pipe to the stainless mufflers at the rear. No cats, no resonators, no nothing. I dunno if this means anything or not.

I am just going to accept the numbers. They are what they are and there isn't anything I can do about it......oh wait, yes there is. :D

How about the timing bump at the end of my graph. Is that anything I should be concerned about??

DLF, as far as track times, that will probably be my next learning experience but it sure feels nice on the street. ;)
 
To me, past 5800 it looks like detonation. Your torque converter can cause lower dunk numbers, they are usually "less efficient" than stock.

Did Brian tune your car at all or did you just do a couple pulls? You could still gain some power with a dyno tune.
 
I'll post up mine as well... from back in '05 with similar mods as yours, but no Kooks headers.

100_1598.JPG


This was at an SCT dynotune session where the car gained ~15 HP from the dynotune compared to the SCT 'mail order' tune. So previous HP level would've been in the upper 230s.

Another problem with a lot of dynocharts is the peak torque number is usually a "spike" and not representative of the true torque. Steve's chart is a good example.

My car is a pain to dyno if the dyno operator does not have the experience to lock 3rd and lock the converter at lower rpms for a 'good pull'. From the looks of it, your dyno operator had the same issue?
 
driller said:
My car is a pain to dyno if the dyno operator does not have the experience to lock 3rd and lock the converter at lower rpms for a 'good pull'. From the looks of it, your dyno operator had the same issue?
Click to expand...

Spot on John! He did say the converter wasn't fully locking and there was some fluid "getting past". He said it wasn't a big deal, but more of like a "it is what it is" situation.
 
Looking at the list of your mods, a lot of the stuff you did doesn't give you power, it just transfers the power you HAVE already to the ground....all except the tranny cooler, that adds 36 hp! :D
 
Since I got the SCT Pro Racer Package, I discovered there is a special "dyno" mode you can load on the chip for the transmission parameters which forces the car to do a very low speed 1-2 shift and 2-3 shift and then locks the transmission in 3rd with a fully locked converter. This allows a full range pull on the dyno with parameters that do not allow a downshift when the throttle is matted.
 
J said:
Looking at the list of your mods, a lot of the stuff you did doesn't give you power, it just transfers the power you HAVE already to the ground....all except the tranny cooler, that adds 36 hp! :D
Click to expand...

Yes J, I know that. I also know the car will do over 150 mph. How fast can you read a tag when I fly past? :p
 
looks similar to my dyno chart. This was with an exhaust and 3.73 gears, not much else of anything done at that point.


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Yup, I see a pattern here. This is the 4th dyno sheet I have now seen with considerably higher torque numbers than hp numbers. Call me a skeptic, but something needs to be fine tuned. My torque numbers are too low and that warble at the end of the graph is only apparent on my dyno sheet. I am going to start off with a colder set of plugs and dyno tune and see where I am at. I think it is time I do something with the tune that is local. This mail order chip thing is just a real hassle and I think the fault still lies mostly in my tune.

A buddy of mine the other day told me that a dyno tune is the way to go. He said something to the extent of "none of the injectors have the same pulsewidth" and that is not something that can be accounted for in a mail order tune. I have also been told by a few that I should run plugs that are a heat range colder and even a 180 degree thermostat. So, in other words, I need a computer hooked up to this car when it is tuned. :)
 
20% is just a wild guess, so you don't really know what crank hp is.

My car with long tubes, cobra intake, tune, gears, converter, driveshaft, etc. made about 250 rwhp. So that's about right. It made 225 rwhp stock.

Remember, the only thing you did to increase HP (judging by your sig) is headers. All those other parts will help you go faster, but not by adding horsepower. Some will actually reduce HP as measured at the wheels. Gears will reduce rwhp (higher ratios are slightly less efficient - although you'd probably never notice this on a dyno)

A local dyno tune is always the way to go. That warble at the end may be timing coming out and going back in, I don't know. Colder plugs may fix it. BTW an injector is nothing more than a tiny valve actuated by a built in solenoid. Pulsewidth is wholly determined by the ECU, it would be the signal sent by the ECU to the injector.
 
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