horsepower estimation?

decobraman · #1 (**permalink**) 05-31-2003, 08:45 PM

Hey guys, new to the forum here. I got a Classic Motor Carraiges cobra with a 5.0 Mustang engine. Its from a 1991. It has a Holley 650 cfm four-barrel carb, Edelbrock aluminum intake, custom headers (made them myself, couldn't find any for side exhaust. Basically straight tubing), electric fuel pump, electric fan, etc. Basically no power loss from that stuff. I waa wodering what you guys think the crankshaft hp is and what the RW hp is (again, Mustang 5 speed with 4.10 gears.)

Any way to up the horsepower? I don't want to go with extensvive internal mods. I also very much want it to be naturally aspired (the ONLY way to go.) I am a mehanic, however, and won't mind switching carbs, intakes, heads, etc. to get more hp.

Thansk, I just wanted your guys opinions on HP ratings and how to increase them.

Ron61 · #2 (**permalink**) 06-01-2003, 06:09 AM

Decobraman,

Get a copy of the Desktop Dyno program. It won't be perfect but it will be close on horsepower. I use mine quite a bit and it normally reads within + or -10 horsepower to the real dyno pulls. However the torque readings are usually quite a bit low and I haven't figured out why yet. You can play with it by changing heads and such and see what gives you the most for the least. I think several of the guys in the club use it.

Ron

blykins · #3 (**permalink**) 06-01-2003, 06:27 AM

Ron made a good suggestion with Desktop Dyno. It was off 4hp with my engine. However, the torque was off like he said...and I can't figure out why either. Oh well.

I'd say you're in the 230-240 hp range at the flywheel. Does the car have a straight axle or IRS? That would change your RWHP.

As for more horsey-power, I'd start with a head and cam change. You can get some pretty big numbers out of a small block without being really radical. Ford Racing offers a 340hp 302, so you know that's do-able with GT40-X heads and a mild cam.

Roscoe · #4 (**permalink**) 06-01-2003, 07:58 AM

Estimations are great and they make us feel good but without going on the dyno you really do not know what you are putting out. You can have a car on the dyno that is mistuned, over jetted, etc. and lose 60 hp even though the 'potential' is much greater.

Just because you estimate the hp at 'x' does not mean you are actually putting it out.

Roscoe

427sharpe · #5 (**permalink**) 06-01-2003, 10:29 AM

C'mon guys..it's easier than that! Just remember that ANY motor
gains 250 hp and 312 lb ft when it's put in a Cobra! Just take the stock factory hp, and the differential above and square the result, then post it!

But to stay on topic, ditto on Desktop Dyno. One caution, don't plug in the static numbers on the main program as you will get some crazy numbers! 1012 hp???? Go thru each screen and plug in the real numbers from spec sheets and you'll get a very close approximation. I guess the old adage is true..crap in, crap out! Then off to a chassis dyno to get the real numbers....

George Snyder · #6 (**permalink**) 06-01-2003, 05:59 PM

decobraman,

Desk Top Dyno is a great tool. It allows you to compare different engine combinations against each other. Saves alot of time & money. I wish I would have done that when I was building the engine in one of my other cars. I didn't and it ended up costing me a ton of money!

Do not treat the numbers that DD tells you as the Gosbel though! Sometimes it is very accurate, sometimes not.

If when you are done and really, really, want to know EXACTLY what your engine is producing, have in Dynoed on an ENGINE Dyno.

Chassis Dynos readings vary from Dyno to Dyno, even from the same manufacturer. They are a tuning tool, and are excellent for that purpose. The rule when using a Chassis Dyno to see how a change (cam, Carb, etc) effects an engine is to always use the same Dyno.
Good luck and take your time.

Bud

decobraman · #7 (**permalink**) 06-01-2003, 06:51 PM

The reason I ask is because dynos around here are nonesistant. The closest is nearly 150 miles away.

Any perfomace upgrades?

Secondly, the car overheats. Anything above 80 degrees and hard running, it starts to overheat. Would a larger, more fins per inch, aluminum radiator fix this?

George Snyder · #8 (**permalink**) 06-01-2003, 07:22 PM

Overheating? Can be caused by many things. Basics.

#1 I would first off pull the thermostat and try running without
one. Later replace with say 160 -180 range.
#2 Backflush the engine and radiator. I'd tell you to check
coolant level, but you will be refilling after you complete steps
1 & 2.

Performance Mods? Sorry, but I can't help you there. I am new to Ford Engines and just feeling my way along also. There are others here though that can and will offer good advice willingly.

Chassis Dyno? Try the locator at this site http://smokemup.com/
Good luck,
Bud

decobraman · #9 (**permalink**) 06-02-2003, 01:54 PM

Where can I find this 'Desktop Dyno'? The closest real dyno is about 110 miles away. Too far.
As for overheating.....we are mechanics. The thermostat is a 180 degree. We already changed the fluids, and backflushed it. I was kinda dirty for 1800 mile, but nothing horrendous. I jst think we need either a bigger radiator or a larger fan.

Ron61 · #10 (**permalink**) 06-02-2003, 02:18 PM

Decobraman,

The desktop Dyno program comes from Motion Software in Brea, Calif. I don't have their website url handy but can look it up if you need. Actually I just found it.

www.motionsoftware.com

Ron

Robb · #11 (**permalink**) 06-02-2003, 02:57 PM

I have Desktop Dyno, and will do a graph of your engine if you provide me the data.

I need the engines compression ratio, and the cam data.

However, as your engine is basically stock, I would guess your modifications are no more then 20-25 additional HP.

-Robb

CSX 4027 · #12 (**permalink**) 06-02-2003, 03:51 PM

Desk top dyno should be used as a very basic baseline for changes that would post the same results from common sense without the software. It is more entertaining than anything else. You could also go to a Fortune teller and find some things to fit your situation. Does that mean the persion can really be psychic?
Or just a good guesser based on other common results?
It can't possibly take into considerational the infinitismal variations that could possibly take place in an engine.
Best Bet..Get a good engine builder or learn to build them yourself.

Newstang4me · #13 (**permalink**) 06-10-2003, 03:19 PM

For a 302 I'll assume you alread have a good air filter, bumped timing(14 degrees or so)combo. I'd go with AFR 165 heads, and get a Demon carb. Alot of your power will come from your "breathing"(heads, cam, intake combo). Also a better ignition system.

Gary