Any dyno tips.

[Dark_5.0]

I have a date with the dyno in mid June to see what my 2 stangs are made of.

I want to get the most out of my session. So can I get some tips from the dyno veterans.

BTW: Any predictions.

[302 LX Eric]

What type of dyno will you be running on, Mustang or DynoJet?

I'm sure you already know this, but the operators should run the dyno with the car in 4th gear. Also, my dyno guy asked me beforehand where he want me to have him stop (rpm wise). I told him around 6000 on the stock tach.

What's interesting is that my peak HP was at 5300 rpm (pre-331 combo). I'll be curious to see where yours is (on the '90).

I was concerned about the car overheating, but it never got above 200* on the second run with very little cool down time in between. I'm sure they'll have a carpet blower or something to help cool the car down b/t runs.

Are you planning on doing some tuning while on the clock or just a couple quick runs to see what they've got in them? If tuning, it would be nice if they had an O2 sensor.

Good luck,
E

[Dark_5.0]

I plan on doing some tuning with a wide band O2 sensor. I am mainly wanting to get the most out of my 5.0. I am guessing around 255RWHP.

I am not sure what type of dyno it is but it is the one that everyone around here prefers.

[BilLster]

might sound silly but do a good tune up first new plugs air and fuel filter, check your coolent ,oil change , o2's

i had a friend get really disapointed when his car kept falling off on the top end after the 3 pulls he checked his k&N and it was like filthy he did one more run without filters and was mad that the first 3 were useless.

let the operator know as much about the car as you can from cam to gears to fuel system before they start .

i actually borrowed a manifold from a shop once to test it against mine and for the $1000.00 diffrence in price there wasnt any noticeable diffrence .

also do you plan on timing changes or fuel pressure adjustments between runs ? (if so make sure tools are handy time is money on the dyno)the dyno operator can give you a wealth of info or he can give you a graph it's up to you. ask about shift points fuel pressure and timing as a minamum.

[Hozer 88GTConv]

I have to second the tools comment...

Have timing marks clearly marked on your balancer(I used permanent marker) and your FPR allen wrench ready to optimize a/f ratio.

I really like the external temp sensor so you can check header temps at the cylinder head to compare temps.

If you are really hell bent on max numbers, drive the car to the shop, throw some ice on the intake while you wait.

I'm sure you know all of this...

Look forward to seeing your numbers and good luck.

[jimberg]

The Mustang ECM uses an adaptive strategy so there isn't much you can do with fuel pressure. Focus your efforts on timing. Going from 12 degrees to 16 degrees netted me 10 hp. See if they can bring in lots of fans to cool down your car between runs. You'll get the most power with your temp gauge reading at about the first notch. A proper cool down netted another 10hp.

Do you know if the dyno is in the air or in the ground? The one I used was in the air and allowed me to walk around underneath the car while it was cooling off. If there's anything under there you wanted to check, bring the tools necessary to check it.

[fiveohpatrol]

A few months back, I went with a friend to Anderson Ford Motorsport's dyno for a tune. Rick Anderson himself was out there watching things over, and to try to make things more consistent, he would lay shop rags on the upper intake, and inlet tube and then spray them with water from a spray nozzle. Then he would monitor the temp with a lazer thermometer and do all the pulls with the intake at the same temp.
So if you want to get the most out of your session, I would reccomend doing the pulls at the same temperature to really see how the other changes effect the power.

My guess for the 90 (cause I used to have almost the exact same combo) is 250rwhp/295ft-lbs. And a compete shot in the dark 275rwhp for the cobra.

good luck

oh and, jimberg, I've heard that about the mustang computer compensating for fuel pressure, and I have never understood how it can do that? It just seems like the only thing that could actually change the pressure is the regulator, which is completely mechanically driven (ie vacuum). Can the ECU somehow control it through a signal to the pump?

[jimberg]

fiveohpatral, it doesn't change the fuel pressure at all. That is mechanical and will remain fairly constant. The computer compensates by adjusting the injector pulse length based on feedback by the O2 sensors. This is all done during closed-loop operation of your computer. Here's how it normally works:

You computer uses the MAF, ACT (air charge temperature), ECT (engine coolant temperature), and BAP (barometric air pressure) sensors to measure how much air is going into the cylinders. The computer calculates the length of injector pulses based on that information. The computer has a predetermined air/fuel ratio that it must maintain for fuel economy and it uses the O2 sensors to measure whether or not that air/fuel ratio is being achieved. If the A/F ratio is too lean, it compensates by lengthening the injector pulse. If it's too rich, it will shorten the injector pulse. It will average that adjustment over time and store it as a compensation value. Let's say your fuel pressure was exactly where the computer expected it to be. The compensation value would be 1.00. Now you adjust the fuel pressure to deliver 10% more fuel than the computer expected. Eventually, the computer would set your compensation value to .90.

When you're at WOT or your engine is cold, you run in open-loop operation. This means that the computer will not use O2 sensor feedback and base injector pulse length only on information by the MAF, ACT, ECT and BAP. These are the times that the computer wants to run rich, but it's too rich for the O2 sensors to measure so the computer just guesses based on lookup tables. The computer measures air, looks up how long to open the injectors, applies the compensation value that was stored during closed-loop operation, and then opens the injectors accordingly.

Adjusting fuel pressure isn't completely useless, but it's not something you tweak on a dyno and hope to maintain. If you want to run on the rich side, you can bump your pressure up and eventually it will come down to the rich side of normal. If you want it to run on the lean side of normal, you can drop it some and it will move up to the lean side of normal. What I mean by the lean or rich side of normal is that normal is a window of voltages that the computer will look for from the O2 sensors. It's a range that as soon as the computer compensates the air/fuel ratio to be within, the computer will stop compensating.

I hope this helps.

[andy669]

I have 24 hour access to a DynoJet at my friends shop. I have Dynoed several cars down there. When I was at WFC this year I was having some troubles with my car so I decided to use the mobile chassis dyno that was there. While I was waiting in line I was listening to the car before me, and it sounded strange. After listening to the next 2 pulls I figured out that they were letting the motor backwind for a few seconds before hitting the brakes on the dyno. I asked them why they would do such a silly thing and their response was, "to save the brake pads on the dyno".

I explained to them that letting a motor backwind is extremely hard on the motor, and that I would not be doing the same. As soon as I let off the gas I push the clutch in, pop the trans in neutral, and let the dyno brakes slow the tires down.

Needless to say, this crew was fairly new and did not quite know what they were doing. They said they had been doing this for a few months, but it seemed more like a few weeks.

Thats about all I can add. Everyone else had good suggestions.

Andy

[BilLster]

sorry Jimberg but fuel pressure isnt controlled that way with Speed density like in his car. also even with maf cars you can adjust fuel pressure for the top end the computer compinsates but when running higher horse power more fuel must be added at wot and the only way to do that is to up the fuel pressure , or change injectors,the computer then drops the cycle at lower fuel requirements but if more fuel is needed the computer cant increase past the top fuel pressure setting

my fuel is set at 54 lbs adjusted on the dyno.

but for maf car your right

[jimberg]

I saw that it was a 90 Mustang and didn't read the speed density part so I assumed he had a MAF sensor. Adaptive strategy still applies, though. The computer only bases its decisions on readings from the MAP (manifold absolute pressure), ACT, and ECT sensors which is why speed density computers aren't that desirable unless they are completely programmable. Feedback is still provided by the O2 sensors.

You're correct that fuel pressure can be used to make injectors provide more fuel at the top end, but without even a cam change, I wouldn't worry too much about exceeding the limits of the stock injectors.

[Coupe50h]

Im curious to see what the 90 makes since he is using the explorer intake, my explorer intake will be out of the machine shop tommorrow, getting ported, and tapping the act sensor hole.

[fiveohpatrol]

and tapping the act sensor hole.

if they haven't already done that, then I'd tell them not to. Its much easier (and less of a flow restriction) to mount it in your airbox like the SN95's.

[Coupe50h]

Well i dont have an air box i have a cai.
I just like to keep things in their original places. but i could see how it restricts that one runner.