Maybe I'm spoiled by my blower motor. But I just knew my 572 was going to make more steam than it did. Trying to figure out why this is all it made, so throwing it out there for the experts to diagnose..
I was hoping for 950+.
Specifications
KB block deck height 10.200 (.500 short)
B1 Originals 69 cc, 2.300 int, 1.78 exh
4.5 stroke, 4.5 bore, 7.100 Oliver rods, Ross pistons and calculated compression ratio of 13-1 rounded down.
Bullet cam, image this is a 4-7, 2-3 swap 55 mm roller.
Tunnel Ram with Enderle mech fuel injection
Headers 2 1/8 diameter 29 length primary, with a merge collector 3.5" outlet x6 length with a 9* transition with a 4 " cone, Collector is 10 inch overall.
Attached is the dyno sheet of last pull.
It needs a little more fuel but this was with smallest pill I had at the time. Just a tad lean. 36* advance
It wanted more timing every pull. We went to 38 but it fell off a little.






Dave

It looks like 4700 RPM for peak torque and from 6800 to 7000 for peak HP
I would take it to the races and try shifting it 6000 RPM and then 6500, 7000 and finally at 7500 RPM to see where it is quickest fastest in all the increments, 330, 660 and 1000 as well as the 1/4 mile Unless it is a 1/8 mile track but I would still try testing the shift RPM to find out exactly what your combination likes at the races
My old pump gas 505 C.I. 400 block stroker motor with a low deck six pack set up on it made peak torque at 4500 RPM and peak HP at 5500 RPM but went the quickest and fastest MPH by shifting that stupid motor at or above 7500 RPM
I ended up trying to shift it at or a little bit above 7000 RPM to help the motor live longer

Some of what the numbers are comes down to the particular dyno.

But....... I’ll agree, those numbers seem way down.

You don’t say what the fuel is, but a 572” with good heads and a TR should be up about 100ft/lbs from where those numbers are.

Looks like one of those “start low/end low” situations.

It’s almost like there is a slight dip in the power curve, right where I’d be expecting the TQ peak to occur(5500-ish).

a 10.200 deck with 7.100 rods and a 4.500 stroke only leaves .85 for compression height on the piston. I don't think you can go any less than 1.06 or so, so I think there is something wrong with the info.

Are the pistons domed?

What is the deck clearance?

The set of b1 originals I have only go 375 at .650 and fall off from there.


Just my first thoughts.

Definitely no expert.

If the heads aren’t “ported”........ the power numbers would make more sense.

And of course, then the question about how “correct” the manifold dimensions are comes into play.

I got ya Cab.. That is my theory when I can get to the track. The info messed with FTI when I ordered the converter. It should flash 61-6200. I usually start my shift point at 6800 but plan om starting at 69 on this one.
I'm more disappointed in the numbers.

Dave

I agree, but this one belongs to a friend and I know he keeps it calibrated. In fact he had to take it apart to replace the starter ring gear so I'm pretty sure he checked it.
Sorry about leaving out the fuel. I run alcohol fuel injection.

The numbers to me were disappointing and I agree peak torque not only seemed low but peak at 4700 surprised me. Everything I've built peaked around 5600..

Dave

Piston compression height is 1.105, slight dome is .280, and piston volume is -8.7 cc because of valve reliefs. Pistons are out of the deck .012, because of machining the o ring groove out. That was to make the cometic gaskets happy. Gaskets are .080 compressed.
The guy I got the heads from had them filled 1 inch from the bottom with epoxy to run on the street. But the opened up the port before they epoxied them. To be honest I think they screwed them up because the cut them into the push rod holes and then put a super thin brass tube for the push rod to come through. Part of my theory of why the power is down is either the ports in the heads are screwed up or the headers are to small.

Dave

I don’t have much dyno experience with alky, but it usually shows a gain in TQ over gas.
So, to me that makes the max of slightly over 700ft/lbs look even worse.

It’s one that makes you wonder...... how can it be so low?

Mine were ported and then filled about 1 inch up. They were flowed for a street engine. Looking at them they had ground them to whatever size they wanted then epoxied them, and flowed. I knocked all the epoxy out and scuffed up the ports before installing them. Mine is not a street engine. So I do not consider them to be ported or at best a hack job at porting.
As to the manifold. It only flows air as I am port injected. Fuel is injected 1 inch above the head port. Alcohol. Although I was listening to a few minutes of Daren Morgan's seminar and he commented that mech injection and port injection would benifit with a smaller port and valve in order to keep air velocity up. Goes against everything I thought but keeping velocity up makes sense..lol

Dave

Yeah, I've just about scratched all my hair out thinking about it.
I'm going to run it as is at first. Then if I come up with something simple to change I will change it to see if it improves. But the changes will be made at the track or just prior to going there.
Kinda hoping someone would see this and say "hey dumba** you got this all screwed up..lol

If it does end up being in the ports I wonder if they could be epoxied and then ported or if I will have to get the ports welded before porting..
Epoxy would sure be easier not to mention cheaper..lol

Dave

Joe called after seeing this and said I posted the wrong dyno numbers.. No graph just numbers. You need to look at the 3rd and 4th lines after the rpm column. He said the first set was with a 50 lb flywheel. The STPIP and STPIT columns show the corrected numbers.

Dave

The dyno I use doesn’t have inertia correction as part of the software, so we’re only correcting for atmospheric conditions.

Our 8 bolt flywheel is a billet steel 11” unit...... weighs at least 45lbs, and then you bolt a drive plate to it.

This is an example of how dyno results from different shops can end up not agreeing with each other.

Since we are talking about my dyno, I though i jump in here. Dave posted his J607 corrected numbers, we were making pulls at 600 RPM per second with a 45lb flywheel. Now most of you should see the issue, all that weight takes Hp/TQ to accelerate. My dyno also has inertia correction which gives the same hp as a step test.
attached is Dave's STPIPw and STPiTr

Joe
edit i was selling some honey while dave was posting.

Dave

What were the uncorrected numbers?

Look at the STPP and STPT columns of the above post.

Dave

I still don't get the shortblock math
7.100+ 2.25+ 1.105 = 10.455 deck height.

But it sounds like you have unhappy ports. If the short turn was fugged up now without the epoxy, would that make the torque come in low and down, then not run up top. With the floor lowered it would seem the it would have to turn more

Assuming the dyno numbers are correct and that the engine is working properly then I'd say your port size is too small. If the ports are the correct size for that engine then it should make a lot more power. The headers are big enough and so is the cam and a tunnel ram should support the power so that leaves the ports as the likely problem. But before jumped all the way to that conclusion I'd check everything over while the engine is on the dyno. Do all plugs look good? Are the EGTs fairly even? Did you check intake vacuum at WOT? Double check firing order? Run a compression check, a leak down, etc.? There are so many ways that engines can get messed up on the dyno you could write a book about it.

Were you really running 9 inches of vacuum at WOT? That is probably a bad number but if it is real then that would be an issue.

if you haven't yet, you may want to verify that your cam specs are actually what they are supposed to be.

I was just going to let it slide but I just can’t.

Who picked that cam? And why the 12 degree split in duration????? That’s way too much exhaust duration. You need maybe 4 degrees split with alcohol and that’s it. You are pissing your power right out the headers. Unless the headers are junk. The size may be a skosh small, maybe. I’d rather see a 4 inch collector on alcohol too but neither of the two can get me to grasp that 12 degree split. That’s insane.


I would call 4 different cam grinders not named Bullet and ask them about a grind for your combo and see how many give you a 12 degree split. The exhaust port on the B1 is more than big enough so that can’t be why all that split.

Andy
The 9 inches of vacuum was the reading for the vacuum pump. I didn't have a manifold vacuum gauge because he is running a big & ugly hat. The blowby numbers are the best i have ever seen on a methanol engine, with each pull the numbers kept improving.


Joe

Your results are similar to mine, a little less power but 70 more cubic inches, here a link to my build and specs for comparison.

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/2864616/1.html
Block
- Keith Black aluminum RB 10.725” deck wet bock from 2014 (I think 440Jim and I were the last ones to get their blocks before they shutdown)
- Drilled lifter galley and tapped for oil restrictions
- Drilled for oil line access on top/back of block.

Heads
- B1 originals, Stage 1 hand porting by Scott Koffel, Ti Intake valves, T&D 1.7 rockers, flow 392 at .700 on Koffel’s flow bench

Intake
- B1 low deck intake with spacers

Cam
- Strange Magic solid roller 4/7 swap .767/.767 276/288 110 Lobe Sep 180 Intake centerline
- Isky EZ-Roll Solid Bushing lifters
- Jessel Belt drive

Rotating Assembly
- Callies Magnum XL 4.25” with 2.100” rod journals
- GRP Rods 7.100”
- Diamond Pistons 4.360”, gas ported, .043 rings, tool steel pins --- 13.2:1 compression ----
- Coated Clevite sbc rod and Calico coated main bearing

Carb
- APD Max Speed billet carb 1250 gas

Okay, that makes more sense but it also makes your numbers even worse since 9 inches of pan vacuum should be adding power to the engine. If everything checks out, cranking test, leak down test, plug read, etc. then I think you have a bad combination of parts. Most likely the heads aren't very good for some reason. Hard to say without taking it apart and looking at it.

Looking at the uncorrected numbers.......
It doesn’t look like a bad weather day at all....... barely over 5%CF.
I mention this to point out that the air wasn’t horrible, so it wasn’t causing the uncorrected numbers to be abnormally low.

660ft/lb from a 572 is pretty soft.

We had an EZ headed 580 on the dyno here a few moths ago.
The uncorrected TQ was almost 100ft/lb better.

OK.
In my defense I am an old man who has crippling CRS evidently. I have been working on parts for 2 different engines while researching rods for my exploded blower motor. And the 7.1 rod has stuck in my head for whatever reason. The rods in my 572 are 6.86 hemi length. So you caught me with my head up my A**
The real math is 6.86+2.25+1.105 = 10.215 deck height on a .500 short KB hemi block. Piston was .010 down in the bore. Piston is now .012 out of the bore after machining the o rings out.

Sorry for the confusion..

Dave

Andy,
All plugs looked great, and yes I looked at them. I don't remember the EGT's and I don't have anything in front of me to see. But the O2 readings are posted and shows a little lean. Engine was really responsive and firing order was verified. If you look at the blow by numbers you will see the measured blow by was 1.8 cfm at it's highest. Every pull the numbers got better indicating the rings were sealing.
The 9 inches of vacuum was what the vacuum pump was pulling, not manifold vacuum. We didn't have a sensor in the manifold, and if we did I would expect a serious drop at full throttle.

Dave

I was was just wondering if the compression was down also... if there was something wrong in the short block numbers.

I get the error heck I posted the other day that .001 over on a 4.28 bore was 4.29.

I say run it and see what the et/weight says....if it's not up to par then flow test the heads.

It is hard to tell, but I would have expected almost 100 hp more, and a higher RPM torque peak. If it would have made 900 hp STP before the inertia correction, that would be acceptable.
The headers are a touch small for a 572 (2-1/8"), and will reduce peak HP. But the Enderle TR intake should be good for power.

My guess (repeat just a guess) is the heads are just not very good.
Even Wade's 508 CID with 12.5 CR and "only" Koffel's stage 1 porting made similar power to yours. But with the expected peak torque RPM.
Koffel says 390 cfm, but IMO their stage 1 isn't a big power producer, but may be fine for 508 CID.

We refreshed a Koffel built low deck 526(4.375 x 4.375) few years ago that had been run in either a puller or a mud truck(can’t remember which).
It had what I would consider a stage 1 type job(bowls and chambers) on original B1’s.
Easy on parts roller with the original style black Dove rockers.
I guess at some point it had ingested some dirt, and was here primarily get taken apart, thoroughly cleaned, honed, heads touched up, new rings & bearings, and put on the dyno.

It made about 830hp(no inertia correction) with a single 1050 on C12 race gas.

The heads flowed 392/266@.800 lift

That is about what Koffel's claims their Stage 1 porting flows.

A couple things fwiw. Id say the compression is a tad soft as well but just my opinion on a race motor, never understood why guys stay so low, unless they plan to run alot of jug through it. Especially with an aluminum block and alcohol on top of that, but just my .02. Next to me the cam seems kinda out in left field maybe. But not knowing anything about the heads who knows. Do you have a port dimension or runner CC for them? I dont really care so much for what the flow numbers are as a gigantic rectangle can move alot of air and be so lazy it wont get out of its own way, but its always the first thing people ask for, like dyno numbers It is definitely performing a bit anemic by the numbers, but since we have the dyno operator here he could best answer what that number translates to real world. Dynos area all different for sure and just tools.

FWIW our 572 B1 in the dragster ran .2 quicker and 3mph faster with a SMALLER header on it. We went from 2 1/4" to 2 3/8" step 3.5" choke 5" to a 2 1/8 to 2 1/4" with a smaller merge collector 3" choke 4"

B1MAXX,

At this point unless someone mentions a quick to do mod or repair, that is the plan. I'll run it this season or until I get my blower motor back together. Then I'm going to build a set of step headers and send the heads off for evaluation and repair/flow.
I m ay try advancing and retarding the cam to see what happens after I get it to the track, since a couple of guys here have said the cam is all wrong. It's been a long time since I ran a normally asperated engine and everything I ran with the blower had a lot of separation. But even those had a LSA of around 110-112. Not arguing with those guys as I am one to take the recommendation of the cam grinders and always ask for their mopar guy..lol And so far I have had good luck doing it that way.

Dave

Al, This engine is down from over 15.6-1 with Brewer heads 56cc to now 13.4 to 1 with B1's 69cc. because of the larger chamber and thicker head gasket to compensate for the above deck piston. I do not have the port dimension or cc, I only measured the exhaust port length to use with Pipemax, it was 4 inches at the floor. To be honest didn't think about needing it. I was recommended to use John Partridge @ Bullet as he is the guru for Mopar down there. I'm not opposed to a different cam but will wait to see what it does and how consistent it is before I spend another 6-700 for a new cam.
According to Pipemax single pipe should be 2.23-2.35 26-30 long with a 4-4.250 x 15 inch standard collector, or 2 step 1st - 2.23x13-15 long, 2nd - 2.35x13-15 long same collector or merge 3.5-4.5 with a 9-15 diffuser.
Headers on it are 2 1/8 diameter 29 length primary, with a merge collector 3.5" outlet x6 length with a 9* transition with a 4 " cone, Collector is 10 inch overall. Length is actually off as I measured from end of the slip to end of collector.

And I agree a dyno is just a tool. But it definitely is a good one..lol

Dave

Jim,
But I'd bet they didn't get those numbers with a hack port job..

Dave

Wade, yeah mine is pretty anemic in comparison. Your build is one I was sort of comparing mine to when it was on the dyno. I need to find a dyno simulator software to play with and see what your cam would do in my engine just for giggles..

Thanks

Dave

Last B1 Original we did, last year, was 540", heads with alot of work done, 420cfm, 2.300 x 1.78, Ti, cam I picked (kind of large roller, around 280-294@ .050, .870 lift gross on intake), 14.7:1, Q16, 1150, KB block, B1 intake I ported...Made 970HP and 825TQ using customers headers (2 1/4 step to 2 3/8, 30" long, 4.5 merge collector). Was a very nice combo, smooth lobes on the cam, made power at 7000 and carried to 7300rpm.
I think maybe tuneup is part of it, but heads sound like the problem...and maybe the Tunnel ram. The ram would have to be right (and the heads) to make great power on a 572.

Very good numbers..

Only disagreement with what you wrote is about the tunnel ram.. Seems everyone that is commenting about it either doesn't understand that all it does is direct air to the heads. Fuel is injected 1 inch above the port opening. I tune each individual cylinder separately unlike an intake with a carb where it has to be ported/flowed and modified to insure air/fuel distribution in the correct amounts get there.


I'm more and more leaning towards the heads and headers, also not totally disagreeing with cam. But in defense of John at Bullet I think he took my info and gave me a cam he thought would work. Part of that info was me giving him flow numbers for an unported B1 head since I had no clue what it really flows.

Thanks

Dave

Keep in mind for a typical cast tunnel ram to make power on a 572 it would need to be designed for an engine close to that size...I'm unaware of one that is. So I would not overlook that in the least. It's a combination of parts that make or break an engine's output. Almost NEVER just one thing!

Are/were there any cast B1 TR manifolds ever made?

The only thing I ever saw was a weld together “kit”.

If someone is buying a sheet metal manifold....... it could be sized for however big the motor is.

Agree.
The intake is the one that Koffles or maybe Mopar Performance had made to go with the heads. It was a 3 piece intake. I bolted the runners to the heads and slide the plenum over them. Squared it up and welded.
Runners were bell mouthed and funnel shaped tapering down to port size, made an open plate and attached a Big and Ugly on top..

Here is what I have.. The Indy intake looks almost identical to the Mopar Performance. Second picture is of a Big and Ugly hat on a tunnel ram.








Dave

In this pic of the kit....... it sure looks like some serious porting would be required to at least one end of the runners.

No argument porting would help. I radiused the entry and port matched at the head. No idea what it flows. But I can't imaging it wouldn't flow ehough air.

Dave

I have one of those weld up kits. I spent many hours on the Bridgeport with that thing back in 1996. A very good B1 head guy told me to open the top of the runners to 6 square inches and taper it down to the port size. It ran the same on a 572 with two dominators on gas and with a bird catcher on alcohol. It made 907hp with the dominators. That was over 25 years ago can't remember the cam specs but I will try to find them.

This is where I think you might be overlooking this. What is the total intake tract length? That is HUGE in power production. Second, what is the plenum volume? Third, what is the runner size in the plenum vs. at the flange and taper? All these things HAVE to work together to make REAL power. Your engine makes power, but it would seem even you are not happy with the results. I'm trying to make you look closer at the puzzle pieces to determine the problem. Or you can leave it alone...

Even back then I thought mine should have made more power and always wondered how a good manifold would have been.

Good to know. Mine had already been worked on when I got it and since I have a friend who has one just like it with no issues I didn't think I would have any. Both are injected engines. Mine fit the ports perfectly when I put it on and I didn't think to measure the top as I wasn't expecting any issues. I'll check it next time it is off (maybe before) but the plan for the future is to build an new one.

Thanks for the info on yours..

Dave

Believe me you guy's have me looking. Any suggestions on dimensions you mention?

Dave