Just got back from the Dyno

GRGT1994 · Nov 10, 2004

Joes95GT said:
Have you ever seen inside of a Flowmaster muffler? If you have, you would know why they kill horsepower. It looks like Flowmaster welded metal bricks in the muffler...

I don't get it. Were you expecting mufflers to add power?

go.rei GT · Nov 10, 2004

GRGT1994 said:
I don't get it. Were you expecting mufflers to add power?

See the 94-95 faq sheet at the top for catback hp numbers, which would have even larger differences on a forced induction application.

moneypit94 · Nov 10, 2004

hey send me the winPEP files at dlb1982@macomb.com and i will get it to were you can post the graphs on here..

Very interesting with the #'s with no c-back... my dad has always told me that open headers would produce more power... But you had to extend them. He said to spray white paint on your h-pipe and where it stopped turning yellow from the heat thats how long you needed to extend them to..

Like i said very interesting.. Another one of those times were later on in life you find out your parents might now what they are talking about... hehehe

tmoss · Nov 11, 2004

moneypit94 said:
... my dad has always told me that open headers would produce more power... But you had to extend them. He said to spray white paint on your h-pipe and where it stopped turning yellow from the heat thats how long you needed to extend them to...

Old racers trick that works. Using a new header extension without paint works too, just look at where the heat discoloration marking on the steel extension stops and cut them off there.

Joes95GT · Nov 11, 2004

tmoss said:
Old racers trick that works. Using a new header extension without paint works too, just look at where the heat discoloration marking on the steel extension stops and cut them off there.

LOL. Tom's one of them old guys who knows about that stuff . Just havin a little fun with ya Tom.

GRGT1994 said:
I don't get it. Were you expecting mufflers to add power?

You missed the point.

On a mild street car with a GOOD exhaust and muffer combination, there is no reason why a car should pick up that much power simply by unhooking the mufflers.

final5-0 said:
A thought or maybe it is a Q, it don't matter. Paul says he has same springs as HoofnIt and has no valve float plus higher rpms.

YES!

I could go on for hours about this because I just learned about it in school, but I'll summarize it...

Valve float is caused by spring harmonics. Harmonics are caused by many things. In cars, the primary (2) reasons for harmonics are from being pushed too close to coil bind or spring compression.

Take a spring in a pen for example. Compress it slowly between your fingers. Right before it coil binds, it's going to buckle and fly out of your fingers. That's harmonics.

Now, do the same thing, compressing the spring between your fingers, but do it much faster. Harmonics are created much faster.

This is the same idea with valve springs. With a higher rocker ratio, the spring is being compressed MUCH faster and it's trying to "jump" (in a sense) out of the pocket.

If I were a betting kind of guy, I'd put the farm on the valve springs if you are really experiencing valve float.

Joe

HoofnIt · Nov 11, 2004

Sorry it took me so long to reply back.

moneypit94 - I emailed you with the dyno run files attached.

If it was ported correctly, it will make a lot of power.

tmoss - you have done so many you probably don't remember doing mine. I sent the lower off to you last spring. I have no intentions of replacing the intake at this time. The Flowmasters are going to be the first thing to go. I will wait for the dyno runs to be posted before I make any other decisions.

With reference to the flows I cannot positively say that the flows alone were taking 8rwhp because we didn't replace them with straight pipes and get a run with just the tailpipes. I really don't know how much power the tailpipes are taking?

As to losing power after 5000rpm, are your distributor & coil stock? If so, you may want to upgrade them.

The dist is stock w/80K miles and the coil is a MSD Blaster. I also have a new stator, cap and rotor. The dyno operator said that the ignition was holding up fine.

On a mild street car with a GOOD exhaust and muffer combination, there is no reason why a car should pick up that much power simply by unhooking the mufflers.

I guess the question is why did it then? You'll notice that the hp went up but the torque did not.

I have a suspicion that the 1.7 rockers are too much for the stock AFR springs. Maybe that is why the power is dropping off so early. The cobra intake should be making power up to 6K rpms.

moneypit94 · Nov 11, 2004

Ok here is runs 1, 11, 15, and 12 of them put together.

I don't know why I couldn't get the a/f to come up on 15. Also the run viewer seems to never match exactly with the numbers you see on the dyno computer but are usually really close...

Joes95GT · Nov 11, 2004

HoofnIt said:
I guess the question is why did it then? You'll notice that the hp went up but the torque did not.

I have a suspicion that the 1.7 rockers are too much for the stock AFR springs. Maybe that is why the power is dropping off so early. The cobra intake should be making power up to 6K rpms.

The 1.7 rockers combined with weak spring pressures are causing the float problems.

When I can get a long enough break from school, I work at my neighbor's muffler shop for some extra loot. I've modified a few sets of Flowmaster mufflers for cars who want to say, "I run the car through mufflers." I basically cut out all the baffling inside of them so they're just a hollow box with the little gills along the side. In the middle, there is this huge wall that completely deflects air in every direction except towards the back of the muffler, causing huge amounts of turbulence. It's very hard to predict dyno numbers, but I'm willing to guess that you would pick up 5 more horsepower simply by switching to a quality stainless muffler. It will also get rid of the dreadful Flowmaster sound.

Joe

final5-0 · Nov 11, 2004

tmoss said:
Old racers trick that works. Using a new header extension without paint works too, just look at where the heat discoloration marking on the steel extension stops and cut them off there.

OK Tom!

You done went and let the cat out of the bag

By saying that kind of stuff I now know that you ain't no youngster

Later
Grady

tmoss · Nov 11, 2004

Your right, I didn't rememer doing your intake off the top of my head. I guess it was done "right" then.

I just re-read the thread and noticed you said you were gonna re-do the lifters to 3/4 turn - please don't. I only take 1/4 turn on mine and feel it's much better than 1/2 or 3/4 turns. Ford at one time actually recommended just zero lash for race cars on the hydraulics.

How was the cam installed? The Crowers have 4* of advance ground in, so waht ICL was it installed at?

MattZ281LE had the SAME combo (even headers) except he used a 77mm MAF and 1.6 rockers and he made 306HP/329TQ.

Touring23 · Nov 12, 2004

Wow, it sure is lean off-idle...vacuum leak?

Joes95GT · Nov 12, 2004

tmoss said:
I only take 1/4 turn on mine and feel it's much better than 1/2 or 3/4 turns. Ford at one time actually recommended just zero lash for race cars on the hydraulics.

My Dad has worked as a mechanic at Ford for the past 22 years, so he's worked with TONS of hydraulic race junk. That's almost exactly what we did with my car. We did zero + "a tad".

Chalk up another one for Tom....

Joe

HoofnIt · Nov 12, 2004

How was the cam installed? The Crowers have 4* of advance ground in, so waht ICL was it installed at?

I have not heard of ICL but I'm guessing you're talking about whether or not I advanced or retarded the cam when I installed it. I did neither; I lined the dots up straight up and down. I guess if what you're saying is correct about the 4 deg. of advance built in that would explain the car not picking up more power with more timing.

I knew about Matt's combo and was hopeful mine would be similar. Do you think the 1.7 rockers are actually costing me power? What do you think will happen to the hp and tq by going down to 1.6 rockers?

5.0snake · Nov 12, 2004

nice numbers....wish mine where that high

stangboy · Nov 12, 2004

It interesting that you guys are saying that Ford used to do 0 lash. I set mine at a 1/2 turn after zero and my rockers are making more noise than they did before I readjusted them. I know the rockers aren't supposed to be making all that noise with a hydraulic cam/lifters. A friend of mine's solid lift valvetrain doesn't make as much noise as mine.

tmoss · Nov 12, 2004

HoofnIt said:
I have not heard of ICL but I'm guessing you're talking about whether or not I advanced or retarded the cam when I installed it. I did neither; I lined the dots up straight up and down. I guess if what you're saying is correct about the 4 deg. of advance built in that would explain the car not picking up more power with more timing.

I knew about Matt's combo and was hopeful mine would be similar. Do you think the 1.7 rockers are actually costing me power? What do you think will happen to the hp and tq by going down to 1.6 rockers?

ICL = Intake Center Line. If the cam is spec'd out at 114* lobe centers, and the cam has 4* of advance ground in, then the dot-to-dot install should occur at (114-4) 110*. The car not picking up power with timing seems to indicate there is another problem as most cars pick up some power by moving from 10* to 14-16* initial. I wish I coould say you have a problem or not and identify it for you. Some combinations of the same engine just don't make as much power, but the fact that added timing did not pick up power is suggesting something isn't quite right. If you could beg/borrow some 1.6 rockers to put on the car to see, it might help eliminate the or verify a spring situation.

tmoss · Nov 12, 2004

stangboy said:
It interesting that you guys are saying that Ford used to do 0 lash. I set mine at a 1/2 turn after zero and my rockers are making more noise than they did before I readjusted them. I know the rockers aren't supposed to be making all that noise with a hydraulic cam/lifters. A friend of mine's solid lift valvetrain doesn't make as much noise as mine.

Ford suggested 0 lash for race engines - they probably WOULD be noisy at that setting. My 1/4 turn lifters are wisper quiet - you would no know their there if I didn't tell you.

tmoss · Nov 12, 2004

Joes95GT said:
My Dad has worked as a mechanic at Ford for the past 22 years, so he's worked with TONS of hydraulic race junk. That's almost exactly what we did with my car. We did zero + "a tad".

Chalk up another one for Tom....

Joe

Any noise out of yours Joe? You do tend to learn something if you listen over a 40 year period.

Joes95GT · Nov 12, 2004

tmoss said:
Any noise out of yours Joe? You do tend to learn something if you listen over a 40 year period.

Yep, a little. Cold starts are loud and it quiets down considerably once temperature is stabilized. It sounds like it's got a solid cam in it at first with the loose-like "chick-chick-chick" sound.

Another thing my Dad was concerned about was setting the rockers because with a minimal amount of preload he's afraid that the minimum will eventually wear to none (bolts backing out due to heat). So we've gone through and set the rockers a few times after the first heat cycles. The car hasn't been started since August, so whenever I decide to screw with it again, I'll probably set them to 1/4 turn and once race season comes (and my car stays together), I'll run them at zero again.

***To all others reading this, it is not recommended by Ford that you run a hydraulic roller valve train at zero lash on the street. There is much more room for failure as lifter preload minimizes. I believe Ford recommends that you run .040" - .060" of preload, but I could be incorrect.

Joe

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