5.0 Stroker NA Build

[Doc Hawk]

So today is the day, again. Rolling out for RET. Videos to come.

I expect the dyno numbers about 5-10% lower than actual output due to the way dynos (don't) interpret 4.10 gears. The way dynos calculate HP does not account for shorter gears, so I am prepared for the discrepancy.

 

[na svt]

So today is the day, again. Rolling out for RET. Videos to come.

I expect the dyno numbers about 5-10% lower than actual output due to the way dynos (don't) interpret 4.10 gears. The way dynos calculate HP does not account for shorter gears, so I am prepared for the discrepancy.

Since most 4vs have 4.10s or 4.30s your numbers will be consistent with others on the forums. Besides, the percentage lost with 4.10s is may 3% when compared to 3.27 gears.

 

[silver_stang]

Patiently awaiting results once again.. Good luck!

 

[Doc Hawk]

Well, the run was successful, but power is nowhere near where it should be and we had some issues. 325 at the wheels at 5000 and a mess above that. We had pinging at 23 degrees all in, and even when we backed out to 21 we have some dips that suggest misfires - perhaps bad coils. With a brick wall at 5000 RPM and a sloppy curve that plummets after 6000, we are also speculating melted cats / clogged exhaust.

I'll scan the graphs ASAP. Looking for input.

Also found one head has oil leaking past the plug grommets, filling the spark plug holes, and the other head has silicone where my newly purchased valve cover gasket and plug grommets should be.

 

[na svt]

I've overlayed a graph of a 96-98 cobra cammed Mach engine onto yours and it looks like your is down on hp and tq throughout the entire powerband.


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[Doc Hawk]

That graph is where we have it now, at a safe 21 degrees advance that the motor will tolerate. That dropped the whole graph about 5 HP across the board. However, even with that, the numbers are similar to what you see for a bolt-on build. This is a cam and stroker combo with head work. It looks like a LOT of power is missing across the board.

Here are some ideas that we talked about. What do you think, NA?

- Cams not properly timed
- Cam damage or additional valvetrain damage from breakdown?
- Low compression on one or more cyls
- Bad coil(s)
- Clogged exhaust (Borla cat back, stock headers/midpipe/cats @ 110K miles, stock cats were run unknown miles by PO with a Predator tune and cat temp override turned off. Greg thinks that may have melted the cats and caused an exhaust restriction.)

Questions:
- Why is the motor balking at 23 degrees of advance? 10.5:1 compression on 91 octane with milled heads and block (not intentionally decked).
- Perhaps clogged exhaust would lead to high temps and thus causing detonation, which would not like ignition advance? Plugs showed HOT read when we pulled them.
- Is there any exhaust solution I can run other than stock that will pass the sniffer test? Not talking CARB legal or visual inspection. Purely asking about emissions numbers.

 

[na svt]

A true 2.5" carted x pipe would definitely free up some power. The graph shows some ignition issues. I'd do a compression check just cause, after all there was done ptv. Bad for the timing, 21 degrees is enough. I only have 22 in mine and I run 93.

 

[Doc Hawk]

Do you recommend OEM / Ford Racing or aftermarket coils for replacement? I only ask because... $279 for stock??? http://www.americanmuscle.com/frpp-coilset-4valve.html

 

[na svt]

Oem

 

[Bmeagher]

Do you recommend OEM / Ford Racing or aftermarket coils for replacement? I only ask because... $279 for stock??? Ford Racing 4.6L 4V Mustang Ignition Coil Set (99-04 Cobra; 03-04 Mach 1; 07-12 GT500) M-12029-4V - Free Shipping!

I had the same issue, with the coils needing replacement. I use the same coils above, it helped tons.

 

[01yellercobra]

If you want a stock mid pipe just to try I have a spare sitting in the rafters you could try.

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[Doc Hawk]

If you want a stock mid pipe just to try I have a spare sitting in the rafters you could try.

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I'd appreciate that! I selected my cams based upon wanting to stay smoggable, so I am dismayed at the thought of having to de-cat or go longtube. Please PM me so we can arrange the loan.

 

[gmsux]

Here's the borderline spark table in use in my Cobra:

500 750 1000 1500 2000 2500 3000 3500 4000 5000 6000
0.899 4 7 9 15 20 22 24 24 24 24 24
0.799 7 9 11 17 21 22 24 24 24 24 24
0.699 9 11 14 22 23 23 23 24 24 26 25
0.599 9 12 16 23 24 25 25 25 25 26 27
0.500 11 15 18 25 25 26 26 26 27 28 30
0.400 13 19 26 33 39 40 41 42 43 44 45
0.300 39 48 50 50 50 50 50 50 50 50 50
0.200 50 50 50 50 50 50 50 50 50 50 50
0.100 50 50 50 50 50 50 50 50 50 50 50

 

[Doc Hawk]

Coils ordered.

 

[shurur]

Coils ordered.

This is torture...

 

[Boss 327]

Any updates?

 

[ranger2339]

This is why I am just going with a used Coyote for my NA build when they start to hit the market. Been reading lots of horror stories about built engines lately.

 

[Boss 327]

This is why I am just going with a used Coyote for my NA build when they start to hit the market. Been reading lots of horror stories about built engines lately.

I haven't had a problem with my build engine and it's been over a year now. Do your homework and don't cut corners. A Coyote engine can have the same problems as any other engine. Their no different.

 

[Doc Hawk]

2001 Cobra NA Comp Cammed 5.0 Stroker Startup & Idle - YouTube

2001 Cobra NA Comp Cammed 5.0 Stroker Dyno Run - YouTube

 

[trxcobra]

nice man, glad you got it up and running good! how do you like it so far?