Ford V8 Discussion Discussion relating to getting the most out of your Ford-based V8 Miata's engine

5.0 hp

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Old 01-17-2018 | 09:03 PM
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pitterpatterbangbang's Avatar
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Default 5.0 hp

Hi all, I have a 1993 5.0 HO in my car. I am not a Ford guy so kind of in the dark here. From what I've read this era of 5.0 should be 225 crank horsepower, I had the car dyno'd when I first bought it and it was 211 to the wheels. Reversing this back out to crank suggests as much as 275 crank hp.

When I originally inquired with the stang people on the mustangforums, they said my wheel hp sounded "about right" for that era motor but that is not what I am reading. Anyone here chime in and let me know if the motor is stock or modified based on the hp I have?

Thanks.
Old 01-17-2018 | 10:11 PM
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I believe they are 215 HP/ 285 lb/ft from the factory. I THINK those are wheel HP numbers but I could b wrong about that.
Old 01-17-2018 | 11:38 PM
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I was always under the impression hp ratings from manufacturers was crank hp as it is the higher number (for advertisement/marketing purposes) unless they specifically state rwhp.

So, I either have a tired engine or a modified higher hp engine at this point.
Old 01-18-2018 | 06:18 AM
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They are rated flywheel from the factory. Yours sounds like it has upgrades.
Old 01-18-2018 | 09:18 AM
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You did not mention any potential modifications to your engine.
Specifically intake and exhaust.
If your swap utilizes a lower restriction cold air intake and headers and low restriction exhaust and a tune you are benefiting from the normal upgrades that wake up an engine.
Old 01-18-2018 | 01:30 PM
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It has Martin's two piece header setup on it. At the time of the dyno it had the 2 extra cat's removed. Also has the k&n filter carb approved intake, I forget the name on it.

I don't think these two items are enough to see the hp numbers I got, so there must be a cam upgrade in it and/or heads. I've just been trying to figure out what my baseline is on this motor before I move forward with things. I plan on a motor rebuild sooner than later I think, something is amiss with it, at 4k rpms the motor has some nasty vibrations, falls flat on it's face at 5500 rpms (but this appears to be normal for this motor) and between 6,000 and 6,200 redline a new noise has appeared that sounds bad so I don't push it there anymore. I can't even describe the noise at 6200 rpms.

Also, thanks to some posts on this site, I see it is possible to bolt on the vortech v-3 5psi supercharger... which is what I want to do. I don't want to go any crazier than that. But first I need to work out the motor woes.
Old 01-18-2018 | 01:48 PM
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You'd have to have REALLY bad drivetrain losses for 211 whp to be 275 crank hp. Worst case maybe 250 crank hp. Stock fox bodies dyno around 190-200 whp, so you're about 5-10% above that. A combo of headers, cat delete, intake, and dyno variability mean this is certainly within normal power numbers. Dynos can vary a lot, like 10-15%, so unless you know that you made 211 whp on X dyno, and most 5.0's dyno below 190 whp on the same kind of dyno, I wouldn't sweat it. If you are going to rebuild it and want a back to back comparison, make sure to go back to the same dyno.
Old 01-18-2018 | 01:52 PM
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Mucho thanks! That is what I've been looking for. I said 275 crank hp was just a possibility based on some calculators I saw. 252 is what I was thinking with a 20% drive train loss or 242 with a 15% loss.

Ok so then the cams and heads are probably stock. From what I've read there isn't any way to tell just by looking at them once they are off and out of the motor, or is there?

Thanks!
Old 01-19-2018 | 06:25 AM
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If they are iron heads, most likely stock. If shiny aluminum, definitely upgraded.
Old 04-09-2018 | 12:46 AM
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211 is right if you ask me. The stock headers were the worst ever made. The noise at high rpm is called valve float. Some nice heads will fix the valve float and power to 6200
Old 04-09-2018 | 12:48 AM
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Adding to last post,
the valve springs are fatigued from age and high rpm. Possibly even a broken valve spring. Might be time to bore it to a 306 and with new bearings

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