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Dyno Results


74_5.0L_Z

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After thrashing away in the garage for the last several weeks, I got the new engine running last weekend. I set the initial timing and fuel pressure, and tried to get the car to idle. The engine ran but had a hunting idle and would eventually stall after a few minutes.

 

Well, I took the car to a friends shop, and we put it on his chassis dyno to break in the new engine and do some baseline tuning. This was the first time that I had ever done the chassis dyno thing, and I must say that it was a lot of fun.

 

We strapped the car down on his Superflow AutoDyn 30 chassis dyno, and he set the dyno up so that I could essentially drive the car and put some miles on the engine. After, about the equivalent of 20 miles of varying load, varying speed driving we decided to make a first pull. The first pull netted about 335 rwhp and the O2 sensors were reading about 11.5:1 at idle and would dip to 10.3:1 under full power (black smoke was coming out of the tail pipe).

 

After the first run, we decided that a fuel pressure adjustment was in order. I gave the adjustable fuel pressure regulator 2 turns of adjustment to decrease my fuel pressure and my idle air fuel ratio improved to 12.0:1. We drove the car on the dyno some more to make sure that the AF stayed in the safe region and then made a second pull. This time the peaks were 348 rwhp at 5400 rpm and 363 rwTq at 4500 rpm. The AF ratios were still a bit rich (~11.5:1) under full throttle, but now the car felt a ton better, sounded better, and now would idle without hunting. I made a third run that was pretty much a carbon copy of the second. After that we quit because my pan gasket was leaking a bit. With a little more tuning of the fuel pressure, I think 360 rwhp is attainable, and he says that with a chip we could get even more. We'll do that another day. Here is the graph of the third run:

 

Run_3.jpg

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Wow thats awesome dude! Do you really need that much power for the racing you do? I was gonna build a 400 Crank HP 5.0 but decided it would be too hard to control. I know you put some good track miles on your car so I bet you have a good reason for an engine that powerful. Very nice job! :burnout:

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It will be a little more interesting to autocross than before (it was already a handful). My goal is to have a car that kicks butt in Autocross and that will run 120 mph in the quarter mile. I'll find out soon if I can get the 120 mph run. With the old motor and ~300 whp I ran 113mph through the quarter. With the new engine's dyno numbers, I'm predicting 121 mph in the quarter.

 

The car was already a pretty good autocross weapon with the old engine, and lack of power was never a concern. I will have to adapt to the new engine and also get some bigger tires.:mrgreen: Sometime around April, I plan to switch from my current Hoosier 245/45/16 A6's to some 275/35/15 A6's.

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Old engine:

 

1989 5.0L engine from highway patrol mustang. I got this engine from a junkyard and installed it and the T5 transmission in my car in 2000. When initially installed in my car, the engine was completely stock and had at least 100,000 miles. In completely stock form, the car ran 13.50's at 100mph.

 

I started adding parts after about a year of daily driving. First, I added Ford motorsport 1.72:1 roller rockers, 24# injectors and 73mm MAF. This got the car to 13.20's at 103 mph. Then I added a Cobra Intake, Edelbrock Performer Heads, Crower 15511 cam, and 65mm TB. This got the car to 12.40 at 113 mph. All of this on the stock (100,000 mile plus) bottom end. I drove it this way for about 6 years during which the car saw ~10,000 street miles, ~100 drag strip passes, and about 250 autocross runs.

 

This is the car with the old engine back in november:

http://www.youtube.com/watch?v=8HrbHKZyRNo&feature=channel_page

 

Lately, the engine was starting to sound like a lot of loose parts flying in close formation.:icon56: It rattled a little on start-up, but still ran well, still had good oil pressure, but was starting to smoke a little. So I thought it was time for a new bottom end.

 

New engine:

New Ford 5.0L block with stock 4.000 bore.

Scat cast steel 3.25 inch stroke crank and 5.400 rods.

Mahle 10.3:1 compression forged pistons, rings and pins

Fidanza aluminum flywheel

Romac Light weight Damper

main stud girdle

The whole rotating assembly has been dynamically balanced.

The heads, cam, and rocker arms are the same parts used on the old engine. I replaced the cobra intake, 65mm TB, and 24# injectors with a Performer RPM intake, 70mm TB, and 30# injectors. I replaced the calibration tube in my 73mm MAF to match the new injectors. The engine is still breathing through the same crappy block hugger headers and exhaust as before. The heads, cam, and exhaust are probably restricting the new engine from making more power, but I don't know that I will be able to use much more for autocross anyways.

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Here are the specs on the cam that is installed:

 

http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=15511

 

The specs listed are for 1.60 rocker arms, but I am running 1.72:1. Therefore, my lift is 0.522/0.503, and my duration is a little increased. This cam is on the small side for my engine, and, I would like to replace it one day. If I stick with a hydraulic roller set-up, I was thinking of using one of these:

 

http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=15512

 

http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=15513

 

Even better, I would like to ditch the hydraulic roller and switch to a mechanical roller set-up. Unfortunately, that gets into a lot more money.

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One of these days, I hope to find out how this engine responds to more cam and some better heads.

 

First however, I want to back up the current dyno numbers with a trip to the quarter mile. Dyno numbers are just numbers until you see a matching mph in the quarter.

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