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Discussion Starter · #1 ·
So about a week ago got the new build up and going. Car runs good feels strong. Had idleing problems at first but dyno guy fixed in a hury. I hauled the car 4.5 hrs to get dynoed yeterday and today. After a few pulls he ad he car was running really good so we started to put some timing into it, ran it a few more times Car made 292 rwhp and 268 rwtq, to me it was aout 20 rwhp short of what i was hoping for.
Car mods are:
stock bore and sroke 4.6 2v
stock cast crank
falcon rods
dss -10cc dished piston with valve reliefs
"stage 3 TEA ported 2v heads"
110 seat presure on valve springs
heads "shaved .030"
Stage 4 MHS na cams
ford gt cam followers
edelbrock 2v intake manifold
6061 pluemun
accufab 75mm tb
egr delete evap delete
dougs longtubes
dougs x pipe
flowmaster hushpower 2 shortie muffers
90mm lightning mass air
42lb injectors
fue lsystem converted to return style
underdrive pulleys
accel coil packs
hvh 1inch throttle spacer
automatic with 3600 stall lockup converter

The dyno pulls were on 91 octain gas was planning on running e85 but didnt knock on 91 so tuner said its not worth running in my sitution. Just feel ar is a few ponies short. anyone have any ideas? ask questions and ill answer.
 

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Sounds like the converter was unlocked....can you confirm? If so there is your 20rwhp you are looking for...auto's don't make for dyno queens. And if the converter isn't locked then it's really gonna show low! Also all dyno's are different...take it to the track come spring and see what she runs. That will be your true indication of power.
 

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You should have easily broke the 300 mark. If I remember right, I was making that on just VT stage two blower cams - with titanium retainers and Crower springs, P51 Intake, Borla cat-back, AccuFab 75mm t/b, C/L 80mm MAf with a JLT CAI.
 

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Out of curiosity if you had plans to run E85 why didn't you go with flat top pistons? I do think the auto is robbing a fair amount of power. With a stick I would have guessed the car would make 330 +/-.

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Out of curiosity if you had plans to run E85 why didn't you go with flat top pistons? I do think the auto is robbing a fair amount of power. With a stick I would have guessed the car would make 330 +/-.
 

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Discussion Starter · #6 ·
Yes the converter was locked up and i agree i thought id be between 315 and 340 rwhp. I didnt go flat tops
because i got a really good deal on the piston and i regret not getting the flat tops.
 

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If you calculate a 20% drive train loss, that puts you at 365hp at the crank. 20% is about what you lose through an automatic. Seems like a pretty solid number for a stock displacement 2v. The edelbrock intake could be costing you some power too. That intake is best on forced induction and high compression N/A engines. What compression ratio is your engine? The dish could be hurting you as well.
 

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Discussion Starter · #9 ·
Dss said 10.74 to 1 on stock pi heads and like y2k said shave .030 should have 10.5 to 11 to 1 compression. Also has 4.10 gears if that matters.
 

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Yes the converter was locked up and i agree i thought id be between 315 and 340 rwhp. I didnt go flat tops
because i got a really good deal on the piston and i regret not getting the flat tops.
315-340 would put you at around 400 at the flywheel. I think your horsepower numbers are pretty accurate. What kind of dyno were you on? Some dynos are stingy, like Mustang Dynamometer. Personally I prefer a stingy dyno that doesn't inflate your numbers or your ego!
 

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Keep in mind that even with the converter locked the auto trans uses additional HP to run the pump. Some say to expect 10 to 12 % loss from this, which is around 30 HP so with that in mind your numbers aren't that bad.
 

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+3 (or however many) on the fact that your numbers will be lower with the auto trans - and that not all dynos are created/run equal.
Build info in your post says nothing about whether the tranny and converter are new - could be robbing even more than you think, and maybe not actually locking up either if not new.

Too much head/cam/manifold to expect more - that is, if you weren't (or aren't) going to run big NA compression to go along with it.

If your motor's not snorting up air (and it's not with the scaled back compression and safe tune) your velocity (for one thing) is lacking with stage 3 heads, stage 4 cams, and (to a lesser extent) the manifold. Pretty big injectors too (though hopefully the tuners good enough to compensate). You are setup to run a crapload of air through there, without nitrous your bottom end isn't very well matched to the top end.

And if you weren't detonating with the 91, sounds like the tune's uber safe (a good thing on a street car, don't get me wrong) but that means you're leaving power on the table there too.

One last note: my japanese nissan engineer quote again: don't chase dots or points on the graph. It's not the number. It's the area under the curve and how you're making use of it (which means the converter/rar setup).

My $ .98
 

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Dss said 10.74 to 1 on stock pi heads and like y2k said shave .030 should have 10.5 to 11 to 1 compression. Also has 4.10 gears if that matters.
That seems high for dished, even with the slight mill. I was thinking 10.5 might be closer (or still a tad high). I suppose they've measured or are doing the math properly - though anything outside of a sb from them (or a personal relationship with someone there) and I still would hesitate, and don't get me wrong, I've bought/raced sb stuff from them in the past.
 

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JCG1 hit the nail on the head. Your peak horsepower shouldn't be the goal, power throughout the RPM range should be your primary goal. Your engine spends much more of its life between 3000-5000 RPM than it does 5000+. Also your head/cam combo could be too much for 281 cubic inches of modular fury. I chose the smaller of two cam designs my engine builder recommended to me, sacrificing top end for more mid range.
 

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Also your head/cam combo could be too much for 281 cubic inches of modular fury. I chose the smaller of two cam designs my engine builder recommended to me, sacrificing top end for more mid range.
I had a sentence that was less polite, but expressed the identical sentiment, though I removed it because I'm trying hard not to become a cranky old poster again lol.

I'll just be more blunt: way too much head/cam/manifold for a NA, non-strokered/sleeved 4.6, 4R-equipped car.
You would have to be spinning that motor pretty seriously to be making use of that topend without some sort of forced induction.

Bigger is not always better. Definitely not on something non-race-dedicated. Despite what she says.
 

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I would see what mph it runs at the track before I got concerned over dyno results.
 

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Looking at your set-up I would say 2 things......the higer CR would net you another 33-40HP accross the board and ditch your intake set-up.....PI with BBK 78mm combo is all you need.....lets just say I tried 6 different intake set-ups and the PI is the only way to go NA......

"ED"
 

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Discussion Starter · #20 ·
Hmmm... Idk i love the edelbrock but i feel its hurting my mid range. Eventually i wanna run a little nitrous also. What kinda cams you running in your auto.what stall speed? I just took out trans to get converter restalled higher.
 
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