dyno time

just dropped off my 529 BB local s. jersey guy. should be ready next week I'm 2nd in line ! Good to see these local engine guys this busy.

Combination mega block, 13.13.1 , s r heads by Porter racing, 371/290 @ 700 . Milodon dual line system , 1150 thumper reworked dominator carb , indy single plane , crank trigger, lunati solid roller

710/711 lift 282/290 at .050. Hughes 1.5 roller rockers. bronze bushed lifter bores . vacuum pump, diamond pistons gas ported .043 top ring!

hoping to see 785 hp/ maybe 660 ft lbs. what you guys think?

Your goals sound reasonable.

I had an extremely similar combo. Made 786 hp on the Dyno. Forget the torque.

I have an SR combo going together now (HardcoreB's old engine that he's re-vamping for me). In it's past form it made about 770 or so with a tunnel ram, but that was at only 11:1 So I think your goals are reasonable too.

I expect mine with some compression bump will be in the 800hp area, depending how good the new intake is.

I think your estimate is good. It could make a little more too.

Do your SR heads have the 2.25" intake valves?
Do you know the final intake port volume after porting?
Is the block bored to 4.500" ? That can help breathing compared to a 4.375" bore, etc.
What size headers? Dyno shop headers or car headers?

2.19 intake valve. 4.508 bore I don't have the intake volume Dwayne might know it's his work. using my headers 2 1/8 to 4" collector with turn out extensions. it's an A arm car headers custom to the chassis.

That combo could easily make more than 800 hp with the big bore size and good heads. You would need to port the intake to make the bigger numbers and the cam will have to be right on the nose. The cam specs seem too big for that engine but if Dwayne picked the cam then it should work. He knows his stuff.

My 514 with EZ heads made well over 800 hp with a smaller cam, but I had 1.85 Jesel rocker arms so it isn't a direct comparison.

flow numbers are incorrect ! more in the 350s / 260s @ 700 so ! will have to see. the car went 9 .00 with 272 / 284 roller. hoping the cam change should put an 8.90 on the window!

What weight and mph at 9.0? That would at least give you a hp starting point.

Any other changes aside from cam?

2785 W D .best 9.017 146 mph with good N J air! lol

Awesome Bob ! looking forward to seeing the results !

John Impulse racing in wall is handling it. He's right next to Martino and wild rides. nice set up he has. see you soon Bill.

well here's the results. Got the flo numbers from Dwayne
s r flow #s
Lift—— I/E
.100— 73/57
.200—147/114
.300—212/165
.400—263/207
.500—310/239
.600—336/253
.700—348/264
.800—359/271

made six pulls . couldn't use my headers , 2 1/8 to 4" used 2" to 3 1/2" ,

Impressive numbers for such low RPM.

Me thinks there is something goofy in this motor
Was the cam degreed? If so do you know where the intake lobe center was installed at? IF so, were?
If not it should be, I've built and dyno a bunch of BB Mopar stroker motors with similar parts and they made peak power above 6000 RPMs, more HP, power and torque than yours
What about valve spring pressures?
I'll look at your first post again to see if that was listed or not.
EDITED, 2nd look, I see the comment about retarding the cam 4 degrees, why?
Every BB Mopar motor I've dyno and change the cam LSA timing liked from 2 to 6 degrees advanced on the intake lobes, none of them like straight up or retarded on the intake lobes, none of them.
That being said I have never used a cam as large as yours is on the duration
I'm still learning so thanks a bunch for posting your dyno sheets

cam was installed at 108 . I also was wondering why the max power was before 6000. I know the headers used where smaller. I have a light car and advancing the cam I understand would move the torque and hp down the rpm range. This was a refresh with a bigger cam. I'm happy with the outcome. moved the timing ,around, retarding -4 . we added 100 rpm to peak hp and picked up 11 hp.Going to see if the aerospace vac pump needs rebuild. I would like to see more inch's of vac. hey maybe its the Dyno !

That dyno sheet looks like the cam is way smaller than 280/290. Are the heads MW port size? I'm assuming they are since you are using an Indy intake but something moved the power peaks down lower than expected. Did you physically verify that the camshaft was the one that you ordered? The dyno sheet looks like the cam is maybe 20 degrees smaller than what you posted.

And what is going on with the oil pressure? That isn't a good situation with the pressure climbing as the RPM goes up. The pressure relief valve might be stuck or blocked. You should set the relief spring so the max pressure is around 70 psi.

Here is a dyno sheet of a 572 inch Mopar big block with EZ heads and a 280/296 cam. This engine pulls past 7000 RPM and makes more than 860 hp. I think you have something funky going on with your engine. Maybe the valve springs were not correct for the cam? This engine uses the 325 big EZ heads which flow pretty well but I'd think a set of fully prepped SR heads would flow more air than EZ heads. The intakes should be roughly the same but the SR heads should have a better exhaust.

Yes Andy the oil pressure will be checked out. The cam was installed as per the cam card 108. Lift and duration was spot on when i installed it . don't know why the power band is below 6000. yes max wedge ported heads. porter racing set up my heads for me. The headers were pretty small he used I assume that also effects the power band. may have been 1 7/8 or 1 3/4 . Mine are 2 1/8 to 4 inch.

Nice motor, glad to see you have it back together and it'll run better once it's sorted and in the car. I agree that something is off that the engine power is at such a low RPM and falls off quickly.

Hopefully you don't take this the wrong way other than constructive help... Lots of people piling on with opinions, but I think the one thing that stands out is the low RPM.

When I asked before what ET/MPH/Weight it ran before, I was impressed by the 9.0, but the 146mph really didn't match up very well. I'd think that would be more like 150~151mph.

I wonder if that's another sign of it making good power down low, but not up top?

Did you re-use the valve springs by chance with the new cam? I wonder if they are dead?


Although if you look at your peak TQ at 4800RPM, and compare it to Andy's 572" dyno sheet... even the peak torque RPM is really low.

Maybe try a cylinder pressure test. If it's through the roof it might indicate the cam is really small, or WAY advanced from what you thought.

at the moment its a mystery the headers I found out were 1 3/4 to 1 7/8 step to 3 1/2 collector. That for sure would effect the torque band I believe.

Now I'm curious to know if you had it dynoed the first time it was built?

At this point, my feeling is this is a classic case of “racing dynos/facilities”.

I wouldn’t change anything til after it’s been in the car and made some passes.

That being said, I’d expect the numbers/curve would look quite a bit different if I’d have tested it here.

Could be something with the dyno but I don't know why the power bands would be moved down so much. But I agree, unless the OP is interested in spending money on an R&D project I'd just fix the oil pressure issue and then put it in the car and see what she does at the track.

100psi from a milodon dual line system isn’t uncommon.
Especially in cool air and 100* water temps.

The system as is, has been run in the car for several years.
I wouldn’t change anything till it’s been verified at the track.

As has been mentioned..... this is not a new combo.
It’s a freshen up with a cam change.

Put it in the car and see how it runs.

So, I'm assuming you mean you'd have tried to figure out what was wrong if you had been dynoing it? And now that I think about it more, I'm almost on the fence as to if I'd just stick it in the car and sort it out. It did run good in the past for what it was! And I'd expect the cam would have picked it up a decent amount ...at least bring the RPM up if nothing else changed? Did you dyno this engine initially? I remember talking to him a bit on the phone long ago and he said you'd done some work on this motor...maybe it was just the heads...IDK

Just Asking,,,Is the intake ported? The torque is insane so I think as long as it hooks it will ET very strong and just shift it fairly low and keep in that sweet spot. The intake should outflow the heads ( or to say it better, easily keep up with the heads) and if it doesn't you're leaving some top end on the table. When Larry Smith ported my 337 single plane for my Chapman Max Wedge heads.... it made a much bigger difference through the entire power curve than I even anticipated, it gained peak torque RPM and HP that cost little to nothing below the curve. Any time I see a wedge that torque peaks at around 4500 might seem to be slightly under ported, but the torque you have is very stout for 529 cubes.

So is the cam degreed at 108? that should be about right for that combo I would think but I tend to agree that strokers tend to like a big lobe that's in early because the piston swings back toward TDC quicker (gives up more displacement per degree of crank angle) ...so (at least in theory) you gotta rely more on the intake charge than say a shorter stroke/longer rod combo of the same displacement. I haven't built many strokers on 112 centerlines and of course the headers are less than ideally sized for anything much over 5200-5400 on a motor that big. That definitely is limiting your top end in that your HP will fall off quicker after peak torque compared to a 2" tube.

Is that a B or RB deck height? Just curious. I'd love to have a 4.500" bore to work with one day!

i agree though, the only dyno that matters it the timeslip, should be a great bracket motr that lives a good long time!! Congrats!

What I’m saying is, if it was hauled here and rested with no changes other than my dyno headers, I’d expect the numbers/curve to be so different you wouldn’t believe it was the same engine.

Why I say that is there is one aspect of those results that is a pretty glaring issue for me, that I have never seen here on this type of N/A build before(and have rarely seen ever), and I highly doubt it would be duplicated here.

Of course, retesting it here........ and assuming what I predict would happen, actually happened....... it wouldn’t have any impact on how fast the car goes.

If the RPM numbers on the dyno sheet were 1000 higher, no one would bat an eye...

I have not seen the result of putting that small a primary on a 530 ish CID motor vs a 2.125 or larger. But I am sure it would reduce the peak HP and rpm it occurs at. But that rpm range is strange.
As mentioned by others, I would just put it in the car and do a couple days of testing with different shift points and your (larger) headers. It still made good HP on the dyno with those little headers.

-4.5 In HG manifold pressure? Was the throttle all the way open?

Vacuum reading is crankcase pressure from vacuum pump.

That’s not the issue I have with the results, especially if the headers in use were in fact 1-3/4 to 1-7/8 x 3.5.

Yeah that size header will really choke it down.

You're doing a pretty good job beating around the bush here. What is your issue with the results?

I’m waiting to see if anyone else picks up on it.

It jumped right off the sheet to me.

Cam placement. Eye opener

when I drove there i was under the impression my headers were going on the dyno since that's why i dropped them off with the engine week in advance. they have 2 bungs for afr. after all this being said I cant say it was money well spent since my headers weren't used and they are not true numbers to my combination ,.But at least I have good ring seal something you may not accomplish during your first burn out!

Found the original time slip 9.017 @ 147.89 in good n j air! . that was a 272/284 660/660 cam. I appreciate the impute from all, a lot of good brains at work! I'm confident I'll get my first ever 8 second timeslip in the near future! I

I'm looking at the retarded cam, a/f ratio is lean and the water temp is really low. No warmup?

I'm going to ask why was the cam installed 4 degrees retarded? I made that mistake on a 500ci, put the cam in 4 degrees retarded, my own fault, wasn't paying attention. Wondered why it wasn't running like it should. Checked the cam, and put the cam back in 2 degrees advanced, it was like night and day.

made two pulls at 108 ,moved the cam -4 just to see what would happen we picked up from 763 to 772. when I get the car to the track i certainly will consider cam position during test tune session! love that Jesel belt! . performance will be the judge!! it may have been a little lean I ran the carb just the way it was.put away. I have the smallest .030 air bleed and 96 jet! thats exactly what the carb ran last season! that also will get changed to a 98.

So am I understanding this cam position right?
Cam LSA 112
original pulls with intake lobe centerline 108 ATC,
Then retarded the cam 4 degrees to 112 ATC ?

yes correct

BFSC is way low?

Am I seeing -4” to -4.5” of intake manifold vacuum? If so Something’s restricting the intake flow big time.
Doug

There are different parameters one can look at to evaluate the effectiveness of an engine combo.

On the dyno I’ve used for the past 26 years, the “better” combos, running on gasoline with a single carb........ have one of those parameters falling into a pretty narrow range most of the time.

For sure, all of the top BB Mopars I’ve tested that were built along the lines of the OP’s combo fall into that narrow range.

The results on Bob’s dyno sheet have that parameter pretty far outside what I would consider the “normal” range........ without there being any reason(in my mind) why it would be that much better.

AndyF’s 572 example, along with Jeff’s 563....... also fall right into what I consider the normal range.

That parameter?
TQ/CI

Bob’s 529 is showing 1.465/ci........ which on the dyno here is extremely rare for a single carb on gas.
The normal range for typical bracket race builds?
Well, here they are normally in the 1.30-1.35 range.

I see nothing in Bob’s build that would indicate it would fall outside that window....... on the high side

So, this also falls into the “racing dynos” theme, which is why I stipulated that the numbers would look quite a bit different if the engine were tested here, with my dyno headers......... in the same way all the other “better” combos belted out 1.30-1.35 TQ/CI.
Perhaps seeing 1.45+ TQ/CI isn’t that odd of an occurrence where Bob tested.
But no single carb BBM has ever really gotten close to that on the dyno here.

If the TQ/CI number for Bobs 529 ended up at 1.35 here, the peak TQ number would be about 715 instead of in the 770’s.

Looking thru a pile of old dyno sheets, I only see one single carb BBM build that exceeded 1.35, which is a 14:1 572 with 440-1 cnc345’s on it...... and that one went 1.37.
There are also quite a few sheets from pretty nice running combos, making what I feel is decent power....... that didn’t quite make it to 1.30.

Sure........”never say never”, but in my mind the chances of Bobs combo making 1.465 TQ/CI on the dyno here is solidly under 1%.

OK yes but the peaks and there corresponding RPM to me makes me consider the cam is not what it was advertised. And the headers being so small they could compound that to help explain the RPM AND the unusually high torq value as well.

Sean, in my mind it’s a dyno/facility thing in this case.

I’ve had my own motor show over a 60hp spread between two different dynos, along with quite a few other engines I’ve tested, that had been tested somewhere else, where the sheets looked different enough you wouldn’t even guess it’s the same engine.

What I’m saying is, in my 33 years of dyno testing....... I’ve seen drastically different numbers, gleaned from different dynos, often enough to acknowledge it’s a real thing.

I still say the right course of action for Bob is to just put the motor back in the car and let the timeslip be the judge of whether the motor picked up with the new cam.
It’s just a new cam, not a new “combo”.

Yes ok and thank you. I just am having a rough time getting around the RPM issues.

I have to say in a side note after talking to Bob some time ago on the phone he is a pleasant/likeable guy and I hope this iteration refresh gets him to his goal...Good luck Bob!

Here’s another thought I had in mulling the results over........
On this combo.......13:1 529” bracket race build....... is the best cam installed position going to be the same if you’re testing with 1-3/4 to 1-7/8 x 3.5 headers vs 2-1/8 x 4 headers?

Fortunately the engine has a jesel belt on it so moving the cam is pretty easy.

Indeed!
One of the nicest people you’ll ever meet.

The wrong headers can certainly cost some power. The Mopar fender well headers are famous for killing 50+ hp when compared to a dyno header. I'd have to see the headers used to guess how much they cost you. Passenger car headers always cost power over a good dyno header. We use custom built Stahl headers on the dyno here. They've worked well for 20 years and make really good power.

Let me add my 2 cents, using a 1 7/8 header on a 529 that you plan on using 2 1/8 exhaust on, gave you a lot of useless info. The HP/TQ will be down, the A/f will be off, the timing won’t be right. The good news is the oil pressure, the vacuum shouldn’t change, and you got to see if it leaked. I ran a 512 with that same cam and when I shorten the 2 1/8 headers from a 32” primary to a 28, I pick up 18hp. My advice is put the cam back at 108, put it in the car and go have some fun.


Joe

Andyf: does that oil pan have a big window in the side?

Yes. That engine had windows everywhere. Valve covers, valley plate, oil pan, etc. That was a dyno mule that we used to test parts.

next post will be the first outing ! I'll do a rental in the spring ! this will have to be "To BE CONTINUED "like the old Adam West Batman week to week episode! thanks for all the discussion!