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Back from the dyno

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#1 ·
Well, at least it didn't blow up.
We made 610 HP @ 6800, and 544 ft lbs of Tq. @ 5100 rpm.
Found out alot of different things at the dyno session. First of, was that the Biggs carb was absolutely flawlessly RIGHT ON. Didn't even have to jet it. Absolutely perfect.
Got home from the dyno about 6:00 pm, ran down to the shop to pick up the SFI bellhousing and flexplate, ran back home, did some quick measuring, tossed on the flexplate and installed the trans. Then tossed the engine and trans into the car.
Well, other than hooking up the shifter cable, cooler lines, and tossing the radiator in, it's ready to rock.
Not bad for a couple of lazy hours worth of work.
Flame suit is on.
Now tell me why it didn't make the BIG HP.
LACK OF COMPRESSION. SIMPLE AS THAT.


_________________



<font size=-1>[ This Message was edited by: drag79stang on 3/9/02 10:54am ]</font>
 
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#3 ·
In a word. NO.
According to all the 'computer animated toy stories' involving punching numbers in, numbers out, it should have made substantially more HP than that.
Am I bummed? No. I'm happy to have an honest to goodness 610 HP. Last year it dyno'd at 576 HP @ 6400 rpm, and 517 ft lbs tq @ 5400. Now that was with a victor jr. and 1 5/8" headers, and junk duraspark igniter. After the dyno session I tossed on the super vic. That more then likely LOST torque and probably HP. I maybe had an honest 510-520 hp and 460 tq. All the little 'games' on computer and doing the calculating (according to MPH and ET), show that's about right.
Now there's for sure 610 HP and 544 ft lbs TQ rocking under the hood. No ifs/ands/buts about it.
I'm already getting ready for next year. SVO motorsport block bored .120" over, HUGE roller cam, and at least 14 or 15 to 1 compression.
But for now I"ll just putt putt along with what I've got..................
 
#5 ·
What are your cam specs and is it a solid roller or solid flat tappet? Those heads are what's restricting it also. a 6500+RPM 418 needs heavily ported Victor Jrs or AFR 225s to breath on the top end. The compression isn't that bad and you lose more low/mid range torque than upper range torque/HP with less compression. The Super Victor intake also needs a lot of plenum work but luckily the runners are a good size compared to the Vr Jr intake. You got a damn good street engine with lots of torque and it will definitely launch/60ft better which is the most fun part of the quarter. You'd be surprised what a Dominator with 2 1/4" adapter will do to HP and torque. I tried a Carb Shop 1040 CFM 4150 and a 950HP on mine and lost 2 tenths with both but put the 9375 1050 Dominator on, the 2 tenths magically appeared. I tried larger and smaller jets on both 4150 carbs but the closest was the Carb Shop 1040 with exactly 2 tenths down. Both 4150s idled better and were more crisp on return road and in the pits but the Dominator out powered them both. This was with a .030 over 351W 12:1 fully hogged out Windsor Sr heads with gutted out Vr Jr intake. The 850DP was clean on the street and had awesome throttle response but lost 1 tenth on the 60ft and 2 1/2 tenths on the big end for 3 1/2 tenth loss and 5MPH down but was a great street carb. I ran that carb once at the track and that's it. The rest of the time it was used on the street. The Carb Shop and HP 950 I tried tuning for nearly a month each not believing they could be worse than the box stock Dominator. Why not borrow a 9375 1050 Dominator and adapter from a buddy to try one weekend. The stock #92 jets squared gave me the best ET and MPH in my 9375. Belive me, it wants more air!

I'm glad it's still in one piece. Are you running it Saturday or Sunday at the track? What's your stall? Gears? tire height? Cam?
 
#6 ·
Kent. The combo that's IN the car as of right now is IN the car for the rest of the season. (unless something goes ooops).
The cam is a solid flat tappet Crane. 272-276 duration, 640-650 lift. .018" lash. 106 centerline. It's in there retarded 4 degrees which puts it at 101.
The carb is a Biggs prepared 950 HP.
This IS a drag only car. IT has always been a drag only car. IT sees NO street playing. (wish it did, but not).
As stated previously, we took an ass kicking because of the compression loss with the head swap. (the heads were the BIG investment this year).
As far as the heads being the BIG loss of power restriction, I don't have the absolute flow numbers on the heads, but I/one can only assume that Ed Curtis has a faint clue what he's doing as far as preparing/setting up the heads.
According to the flow data (from the dyno session), the air volume/intake/user ability of the engine is maxed out for this application.
If I did something different, (i.e. compression/cam, etc, etc), then for sure I would ponder going even BIGGER with carb, etc.
And, NO, I do not use nitrous on this motor. ONLY my chevrolet (past curse), had to have the juice to run 10's and 9's.
610 HP and 544 ft lfs. tq ain't nuthin' to sneeze at, I'm thinkin'. AT least from my end. Granted, like I said, I'd of loved to have more, but I hear stock block 351's (especially later model years, like mine), DO NOT SURVIVE OVER 640-650 HP RANGE VERY LONG).
 
#7 ·
On 2002-03-08 07:58, drag79stang wrote:

The cam is a solid flat tappet Crane. 272-276 duration, 640-650 lift. .018" lash. 106 centerline. It's in there retarded 4 degrees which puts it at 101.
Are you saying the LOBE SEPERATION is 106 degrees? If so, installing it 4 degrees retarded would put the intake centerline at 110 degrees. I would think installing the cam straight up or advanced would improve performance. It would definitely increase cylinder pressure. I would install the cam at four degrees advanced... especially with relatively low compression ratio. (low, considering the 272/276 cam)

If you don't want to change anything, at least try this. I think you can squeeze a bit more out of it.


Good Luck!
 
#9 ·
Are you gonna race it this weekend or is the track there still closed? You didn't say what the seperation angle on the cam is, only the intake centerline. I'm just curious, that's all. What stall ya got in it? Done a burnout in the garage yet?
 
#10 ·
The centerline is 106.
I still have to toss the driveshaft in, the tranny dipstick, (pain), New one, so requires customizing/fabricating), and shift linkage.
Also the steering linkage/bar is not on.
Oh yeah, the radiator. Waiting for the purple stuff (coolant additive), like wetter water to arrive from local parts emporium, also.
Then fill the trans up with fluid, and vrooom. I'm sure by saturday evening, sunday at the latest, it'll have some 'er, uh, marks in the garage....heh heh heh
 
#11 ·
Forgot to answer the 'other question'.
NO, no racing until I think absolutely late March, or early april.
We just got a couple of inches of that white **** last nite. Actually snow and ice mix. Yuck.
Guaranteed you guys will be the first to know the results, (again, good/bad/indifferent).
 
#14 ·
We'll see what happens. The motor/trans/everything is hooked up/working. I fired it up saturday with ass end in the air to make sure trans worked. Ck levels, etc. Damm, that thing's loud.
Spent most of today just detailing/dicking around in the garage. Lots of little things to do, but the weather's too crappy out to get my trailer out of storage, and load up and find a road to 'er, uh, 'test drive' it.........
 
#16 ·
Yeah, and it wasn't even close. I forget the numbers, but the HP was WAAAY up there, as well as the torque. (funny, asked my dyno guy the same question this year as last year.:" What do you think of the desktop dyno and other computer related engine power assumption makers. His reply: "Yeah, those computer games are fun." Nuff said...........
 
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