dyno day

[kylezx10]

290hp 339tq lower then i was expecting. thats 336hp 390tq at the crank. 347,10 to 1, procomp heads, airgap rpm, 575 demon, try ys, lunati 51017 218 in/228 ex 536 lift, the torque curve is nice & flat and its a hoot to drive the numbers bother me but it gets 18.3 mpg. whats wrong?

 

[847b]

The 112 lobe separation angle on the cam would tend to make a wider power band with less peak power.

Which Procomp heads?
What transmission? (i.e. A C6 chews about 25 hp more than a C4)
What size are the tri-y's?
Roller rocker arm, right?
Was this a Mustang dyno or a Dynojet?

Off hand nothing looks glaringly out of place. 18.3 mpg something must be working right lol.

 

[-Nathan-]

anyway you could post the dynograph? Id be interested in seeing it. On a side note...seems odd to me youre only running a 575cfm carb. I built an engine for my brother, using Trickflow twisted wedge heads: 170 cc intake ports, 2.02 intake, 1.60 exhaust valves, a Comp Cam FW XE270 HR-12 270 intake 276 exhaust, with Trickflow 1.7 hydraulic roller rockers, BBK 1 5/8” unequal length shorty headers, a weiend dual plane intake, and used a holley 650 cfm carb, and this is just on a 302, not a stroker motor like yours, and it made right around 300 hp. Considering that youre running bigger top end gear, Id assume perhaps youre starving the motor of fuel? just a thought. What does your a/f mixture look like?

 

[kylezx10]

.pro mag roller rockers, cheap ebay try ys, 180 pro comps,T5, mustang dyno. had a different tuner look at dyno results,says Im lean went up 2 all around feels stronger. and the curve gets lumpy after 4600 and stops making power dude says its detonation, going to try his dyno-jet next week. the 575 demon was BGs recomendation. I told them Im trying to keep it a daily driver and I love the torque if I can make it to 300 rwhp I'll be happy

 

[-Nathan-]

I figured it was running a little lean. Does it spark knock at all under load? And what do the plugs look like after a spirited drive?

 

[fordmike1]

290hp 339tq lower then i was expecting. thats 336hp 390tq at the crank. 347,10 to 1, procomp heads, airgap rpm, 575 demon, try ys, lunati 51017 218 in/228 ex 536 lift, the torque curve is nice & flat and its a hoot to drive the numbers bother me but it gets 18.3 mpg. whats wrong?

WOW sorry to hear this.

I just did a engine for my friends 95 GTand it made very close to the same numbers.
Started with a stock 98 Explorer engine did a valve job on the GTP heads with better springs to match the cam, Ford F-cam, Cobra intake, shorty headers, stock 95GT t-body and mafs oh and a new ford stock oil pump.
The car put down at the tire 282hp & 321tq with a tune.

 

[-Nathan-]

18.3 mpg....thats your problem. Unless your talking about diesels, it sounds like that motor is starving for fuel. Bump it up, lose some mpg and get those hp numbers up! for what you have into that motor, I would feel safer running it richer. Plus you dont want to run it lean, overheat it and burn through a set of head gaskets.

 

[originalnitro]

kylezx10,not trying to rain on your parade but you asked what wrong?
Heres my 2 cents procomp heads are cheap chinese junk, the seats fall out,
The seats are not concentric with the guides,and dont flow worth a danm without a lot of work.
The carb is to small need to go bigger.
You got to feed the stroke!

 

[baddad457]

290hp 339tq lower then i was expecting. thats 336hp 390tq at the crank. 347,10 to 1, procomp heads, airgap rpm, 575 demon, try ys, lunati 51017 218 in/228 ex 536 lift, the torque curve is nice & flat and its a hoot to drive the numbers bother me but it gets 18.3 mpg. whats wrong?

There's nothing wrong here. You built what you wanted. The carb isn't neccessarily too small either.(unless the dyno was showing a high vacuum at WOT) Jet it up a few sizes and enjoy, who cares about total output numbers if you're happy driving it ?

 

[NastyZ06]

Those numbers sound spot on for what your running. It's going through an auto too. And those aren't the best heads and if I were you I would change to the trick flow stage 2 cam if your looking for more power. But for what you or anyone else is trying to do it sounds like you have a really awesome setup.....these are trucks not racecars. A nice broad torque band does wonders. Enjoy the new setup. I'm contemplating a turbo for my 4.0, a 5.0 swap or a lightning engine swap. Just want the smallest headache possible

 

[847b]

Figure if jetting up gave 10 hp (crank) you're at ~1 horsepower per cubic inch. Pretty reasonable for a healthy street engine. Chassis dynos are very subjective but give excellent information in back to back tests. I would not be super concerned with the baseline data it provided.

 

[red85]

There's nothing wrong here. You built what you wanted. The carb isn't neccessarily too small either.(unless the dyno was showing a high vacuum at WOT) Jet it up a few sizes and enjoy, who cares about total output numbers if you're happy driving it ?

Very sage advice from a guy who knows what he's talking about. You built it to have fun with it so go do that!