Engine guys do these chassis dyno numbers look good?

[A34]

Hey Guys,

I took my car to a chassis dyno shop and was wondering if the numbers it turned sound about right for the combo I have, and if they are better than a stock 440.

The car is a 69 Charger 440 4-spd with 3.54 Dana.
It turned 298.6 HP at 4800 RPM, and 396.3 ft-lbs of torque at 3400 RPM. The dyno guy said most stock 440's turn around 320 ft-lbs of torque.

Here are the engine specs,

The best run was at 35 degrees total timing backed down from 38.

69 440 with steel crank, .020 over, balanced. Standard 906 heads with larger intake valves and unleaded seats. Compression is around 9.45. I told the builder I wanted 10:1, but that's another story.

Factory intake manifold and exhaust manifolds, H-pipe and hemi mufflers. Carter Thunder series AVS - 800 CFM

Hughes HEH1928BL Camshaft
Intake Valve Lift 1.5 .489
Exhaust Valve Lift 1.5 .524"

Intake Duration at .050" 219°
Exhaust Duration at .050" 228°

Lobe Separation Angle 111º

Intake Opening at .050" 1.5° BTC
Exhaust Opening at .050" 48° BBC

Intake Closing at .050" 37.5° ABC
Exhaust Closing at .050" 0° ATC

Adjustable pushrods for cam.

factory dual point with pertronix ignitor kit installed, stock coil, stock wires, stock champion plugs.

The dyno guy said you could average 25% loss of efficiency, which would put the numbers at 373.25 HP & 495.38 ft-lbs at the flywheel. I guess you could add another 15% if you wanted to figure gross w/o the alternator and power steering.

The car had a bad exhaust leak at they dyno, I got it home and tighten the exhaust manifolds and 95% of it went away. Wish I'd thought to do that at the dyno, but I thought it was the heat riser. I had the heat riser welded up, but I guess it's leaking a little, or maybe a gasket is leaking.

I also tuned the carb a little more as it was originally tuned at 38 degrees timing. I think it's a little lean now, so there may be some more power there if I mess with it some more.

Anyway, next stop is the drag strip to see if I can shift worth a dang and break into the 13's.

So, what do you guys think, are those numbers respectable?

[YGBSM]

Sounds pretty respectable.  Usually you assume 15% drivetrain loss going from SAE net to RWHP.  Maybe the dyno guy meant 25% loss going from SAE gross to RWHP. 

[A34]

My goal was to keep it like I had it in high school with a few hidden upgrades to increase power. I talked extensively to my engine builder and Hughes engines while putting the package together to be sure I got it right. Can't say I'm completely happy with the results.

I wasn't expecting 500HP, but a little more than it's showing now. I'll see if I can find a few more hidden in there. Maybe a K&N air filter element would free up a few hidden ponies.

If I can't, I'm not gonna worry about it, and I'm not changing anything that would be externally different from stock.

Although, in high school I did have slots on it. Hmm... See pic below, what do you think? Slots with redlines or polyglass for that nostalgic look?

Nah, I like the steelies, and I don't have to go buy anything else.

[Challenger340]

Do you know how the "9.45:1" Comp. Ratio was arrived at ?

Is it a "guesstimate" from parts spec sheets, or was it actually measured/CC'd ?

What Pistons were used in the build ?

Seems a little low to me.

[firefighter3931]

The cam is a little on the small side (duration) and is probably holding it back. I like the split pattern grind for a stock head & HP manifold type build but the 4800rpm redline indicates that it wants more cam. 

Based on the parts selection it appears to be making what it should be. 


Ron

[A34]

Do you know how the "9.45:1" Comp. Ratio was arrived at ?

Is it a "guesstimate" from parts spec sheets, or was it actually measured/CC'd ?

What Pistons were used in the build ?

Seems a little low to me.

Yes, the heads were measured, I forget the cc's now, but with the head gasket the builer used and the pistons, it came up to 9.45. I told him I wanted 10:1, but he didn't do as I asked. That's a very sore subject with me right now. I'd have to look at my docs on the pistons, but I think he used those Hypereutectics?

Seems low to me too, which is why I'm asking for opinions of guys with similar engines.

[A34]

The cam is a little on the small side (duration) and is probably holding it back. I like the split pattern grind for a stock head & HP manifold type build but the 4800rpm redline indicates that it wants more cam. 

Based on the parts selection it appears to be making what it should be. 


Ron

Yeah, I spoke with Hughes Engines about this at length prior to building the engine, and described what I was doing with the car. They recommended the cam. Where most people over cam and over carb, I think most cam vendors under cam a car. I called back him after my car's initial dyno pulls and got several excuses about why it didn't make the numbers he predicted it would. I'm very disappointed, I had heard good things about Hughes and their cams.

Without going into a lot of detail here, I've had so many issues getting this thing to run, that I just don't feel like putting another cam in it. I need to get the best out of what I have and not sweat it until, I build it again in a few years after I've hopefully worn it out. 

[firefighter3931]

How does the car drive ? I'm sure it's a blast to cruise with all that torque and the 4 spd. 

Personally, i would have gone with more cam.....something like the Comp XE275HL .904 lifter Mopar grind with 231/237 duration @.050 and .525 lift intake/exhaust.

For now, just enjoy the car and tune the most out of it....you can allways upgrade the cam at a later date. 


Ron

[Challenger340]

Well, 9.45 is probably all you want anyways, for todays pump fuels and the Iron heads.

Look at it this way, "you've got stuff in the Bank for later", with a Cam swap down the road sometime.
Still outa run great with those numbers !

[jacb]

Personally, i would have gone with more cam.....something like the Comp XE275HL .904 lifter Mopar grind with 231/237 duration @.050 and .525 lift intake/exhaust.

Ron

Hi Ron

You may be interested in Popular Hot Roding's Engine Master Magazine Summer 2009 (Volume 12 No.2) - Page 44.

Steve Dulcich compares PAW 10323, Comp Cams XE275HL and a Comp custom grind XFI camshafts in a 440. The Comp custom roller grind has an advertised duration of 264/276 (214/224 @ 0.050) with a lobe separation of 112 degrees seperation and 4 degrees advance. The lobes used were 3013 on the intake and 3035 on the exhaust.

Suffice to say the custom cam beat the XE275HL (21-227-4) hands down.

Regards

[440Ramcharger]

I have a Hughes cam in my 440 Ramcharger that is very close to your specs. HE1423BL. This is the "old" grind and just a bit smaller. I really believe with the gears that you have, you are going to enjoy this cam. Especially with the weight of the Charger. Tire blistering torque my friend...

[DixieRestoParts]

 

[A34]

Thanks for the info guys. I still need to do some more carb and distributor tuning and then I'm gonna take it back to the dyno. Will hopefully get it to the dragstrip too, before they shutdown this summer. Maybe if I'm lucky, I'll get it into the 14's. 

http://www.youtube.com/watch?v=8zsdXG8S_2Q

[HPP]

I've got to say, allthe dyno days I've ever done have had a lot of guys scratching their heads wondering what happened to their 5000 horse combo. Your numbers sound very repsectable for a mostly sotck appearing street combo.

What's your compression ratio? Hughes likely choose the cam they did based predominately on the ratio you chose. The best way to make power is via cylinder pressure. The piston, head/chamber, and cam combo all need to be dialed in perfectly. The cranking pressure in your engine can be dramaticlly effected by cam duration (as well as altitude or barometric pressure)and it is entirely possible for a 9.5:1 motor with too big of a cam will only have an effective dynamic compression ratio of around 6.5 or 7:1. Your smallish cam is probably a compromise of rpm range against available cylinder pressure. You have decent torque numbers, I'm thinking it will still be a kick in the pants to drive even though the numebrs seem smallish.

[A34]

I've got to say, allthe dyno days I've ever done have had a lot of guys scratching their heads wondering what happened to their 5000 horse combo. Your numbers sound very repsectable for a mostly sotck appearing street combo.

What's your compression ratio? Hughes likely choose the cam they did based predominately on the ratio you chose. The best way to make power is via cylinder pressure. The piston, head/chamber, and cam combo all need to be dialed in perfectly. The cranking pressure in your engine can be dramaticlly effected by cam duration (as well as altitude or barometric pressure)and it is entirely possible for a 9.5:1 motor with too big of a cam will only have an effective dynamic compression ratio of around 6.5 or 7:1. Your smallish cam is probably a compromise of rpm range against available cylinder pressure. You have decent torque numbers, I'm thinking it will still be a kick in the pants to drive even though the numebrs seem smallish.

Well, I wanted the CR to be stock at 10:1, but after doing the math, I think it's more like 9.45, which really peeves me. I know it's better for pump gas, but I don't mind buying race gas and mixing it. It's not like I drive it everyday. And, it's what I told the engine builder I wanted. Anyway, it does have alot of cylinder pressure, 160psi I think, and it doesn't want to start after it gets hot. I'm told that's due to today's fuel.  Another reason to mix with racing fuel.

The thing is it just doesn't feel stronger than when I drove it 20 yrs ago with 80K miles on the engine. Maybe that's time playing tricks on me. 

Thanks for the comments fellas.

[A34]

Did some more wrenchin' today. Moved the pertronix setup from being run off the coil to the switched side of the ballast resistor. Also replaced the 40 yr. old coil with a new date coded one. 

Then took it for a drive, still had a top end stumble. Checked the fuel pressure, a whopping 3 lbs. So much for the stock replacement Carter pump from Autozone.

I had a Carter Hemi type pump sitting around, so with a few slight adjustments, I put it on the car. I have not checked the pressure yet, but I took it for a test drive and it pulled hard through 1st and 2nd, no more stumble at 5000 rpm. Didn't get to run it through 3rd and 4th, but I have good feelings about it(and high hopes). I'll check the pressue tomorrow and take it for a bonzai run on the interstate. 


I'll post then about the results.

[firefighter3931]

Good work ! Another member recently burnt up a coil with the Pertronix setup...he did not have a ballist resistor. 

I gave him an old Mallory voltmaster coil i had lying around and he installed it with the a new ballist and it runs great. Check your old coil with an ohm meter...acceptable resistance is 1-4 ohms. More than likely it was on it's way out. 

Fuel pressure is another biggie....you need to let the big dog eat ! 


Ron

[A34]

Thanks Ron, I'll check it out. Today turned out to be a lazy Sunday. It's rained all day and I have just laid around with the wife and kids watching movies. Sometimes you need those days too.

[GreenMachine]

 My cam is similar to yours 216/228 @ 50   .454/.480 lift. I have the Eddy RPM heads and 3.23 gears. I wish I had gone with more cam too, but it'll do 13.3 in the 1/4, and I get 11 to 12 MPG. It has plenty of power to be fun, just not scary fast.

[HPP]

Well, I wanted the CR to be stock at 10:1, but after doing the math, I think it's more like 9.45, which really peeves me. I know it's better for pump gas, but I don't mind buying race gas and mixing it. It's not like I drive it everyday. And, it's what I told the engine builder I wanted. Anyway, it does have alot of cylinder pressure, 160psi I think, and it doesn't want to start after it gets hot.

160 psi is fair, but is still a bit off the mark for needing premium, much less race gas. General rule of thumb is that you can run between 180-190 psi on pump gas, but your cam timing, ignition timing, and fuel mixture need to be spot on  to avoid problems.

Here is a compression calculator I like to use because of not only factors in the engine parameters, but also the operating altitude, which is vitally important for some of us. While this site deal primarliy with Harleys, they are a four stroke otto cycle engine just like a V8, so the theory of operation is the same. http://www.rbracing-rsr.com/comprAdvHD.htm

Something you can do for a quick .5 ratio boost is replace the composite head gasket, if used,  with a steel shim gasket.

[A34]

Well, I wanted the CR to be stock at 10:1, but after doing the math, I think it's more like 9.45, which really peeves me. I know it's better for pump gas, but I don't mind buying race gas and mixing it. It's not like I drive it everyday. And, it's what I told the engine builder I wanted. Anyway, it does have alot of cylinder pressure, 160psi I think, and it doesn't want to start after it gets hot.

160 psi is fair, but is still a bit off the mark for needing premium, much less race gas. General rule of thumb is that you can run between 180-190 psi on pump gas, but your cam timing, ignition timing, and fuel mixture need to be spot on  to avoid problems.

Here is a compression calculator I like to use because of not only factors in the engine parameters, but also the operating altitude, which is vitally important for some of us. While this site deal primarliy with Harleys, they are a four stroke otto cycle engine just like a V8, so the theory of operation is the same. http://www.rbracing-rsr.com/comprAdvHD.htm

Something you can do for a quick .5 ratio boost is replace the composite head gasket, if used,  with a steel shim gasket.

Thanks for the info !!

I've been debating doing the head gasket swap.

[Challenger340]

I've been looking at this thread for awhile now.

Didn't wanna say anything, it's the old saying that "if ya ain't got anything good to say, then just shutup",
but,
if you're on here, you must be looking for opinions/suggestions ?

So, if I do say anything here to offend you, I'm sorry.
Please take this with a "grain of salt", I'm NOT trying to offend.

IMO, 298hp on a MD250 is low.
1.)Get more Camshaft
2.) Remove Heads and Inspect;
* Valve Sealing/actual Bowl grind.("tips" available depending upon whats found in there)
* re-verify actual C.R. measurements before re-assembly.(9.45:1 with Iron should be fine)