FE Power Forums
FE Power Forums => FE Technical Forum => FE Engine Dyno Results => Topic started by: CaptCobrajet on September 04, 2020, 09:47:09 PM
-
We ran this unit last week. There was a little more in it, based on past info, but we ran out of time. Customer was looking for around 800 hp, and 700-ish torque, so when we got past there, we didn't beat it on it too hard. I had 31° timing in it, but it had a rather large dome by my standards, and a 72 cc chamber. I usually run much smaller chambers, with just a bump dome, but these heads migrated from another project, so more dome was needed. I think another 2.5 ° would have shown more power. I reckon they can test that in the vehicle.
Cubic inch: 535 (4.345 x 4.500)
Peak Horsepower: 893 at 6500 rpm
Peak Torque: 794 at 5100 rpm
Compression ratio: 13.5:1
Camshaft: .700 lift solid roller
Heads: BPE MR Race Pro Port Edelbrock
Manifold: BPE modified BBM Tunnel Wedge
Carbs: 940-ish cfm modified center squirters, inline with factory style linkage.
-
Very nice Blair just curious as to what block and what had to be modified for the extra stroke. 900 horse and mild, meaning what camshaft wise.
-
That’s outstanding!
-
Holy moly! 2.5 degrees away from 900 hp with a 700 lift cam ? Am I reading this right ?
-
You have a knack for getting more with less.....extremely impressive
-
Very nice Blair just curious as to what block and what had to be modified for the extra stroke. 900 horse and mild, meaning what camshaft wise.
It's a BBM iron block. No mods to the block for 4.500. I used a 2" rod journal, and you still have to clearance the back four rods so they don't bump the camshaft. About the same as a 4.375 with a 2.200 crankpin. I consider it mild because it doesn't have to turn big rpm, it uses stainless valves....no titanium, it has 750# over the nose, .700 lift....an early Drag Week grind like I used in Miller's Cougar several years back, and low timing requirement. It has compression, but not "end of the scale" compression. It also doesn't require a bunch of funky heim jointed carb linkage, or Dominator carbs that don't drive very well unless wide open. It's a fairly basic combo of stuff that works together.
-
Wow, that is impressive. But not unexpected from BP.
-
That's some darn righteous FE steam, Blair. Nice work! The red truck NEEDS a 4.500 arm.
-
Wow, that is pretty impressive stuff. Curious about the crank and rods.
Was this head one that required a modified valve train ( forget what you call it, you install a bar across the head because ) ?
Amazing.
-
Excellent explanation easy to understand and it makes the build more impressive. See you at the Beaver
-
Blair, that's outstanding, from a engine that large. 1.67 HP per CI.
Can you tell us the valve size and how much the heads flowed.
-
Blair, that's outstanding, from a engine that large. 1.67 HP per CI.
Can you tell us the valve size and how much the heads flowed.
This particular one has 2.220 intake and 1.680 exhaust valves. I didn't intend to turn it real high, so I used the small valves to make torque where it wants to reside rpm-wise. That makes it real snappy with the inches and 13.5 static. If I was going to the end with it, more cam, a different set of angles on the valvejob, a 2.300 valve with a little more cross section in the port, would all have added up to quite a bit more power. It also would change the operating range. This engine will run for years reliably with a 7K shift point and 7300 through the traps.
The heads flow pretty good. Nevermind the numbers, as it is only one yardstick of several attributes that matter.
-
What would you estimate output to be if this engine was 10.5:1?
Blair, that's outstanding, from a engine that large. 1.67 HP per CI.
Can you tell us the valve size and how much the heads flowed.
This particular one has 2.220 intake and 1.680 exhaust valves. I didn't intend to turn it real high, so I used the small valves to make torque where it wants to reside rpm-wise. That makes it real snappy with the inches and 13.5 static. If I was going to the end with it, more cam, a different set of angles on the valvejob, a 2.300 valve with a little more cross section in the port, would all have added up to quite a bit more power. It also would change the operating range. This engine will run for years reliably with a 7K shift point and 7300 through the traps.
The heads flow pretty good. Nevermind the numbers, as it is only one yardstick of several attributes that matter.
-
What would you estimate output to be if this engine was 10.5:1?
I suspect it would lose 30-35 hp per point of compression. Probably around 800 power and 700 torque. I am thinking real serious about doing one like that for my Hondo Day Cruiser, so I may get to find out. A dish piston would be more efficient, so losing the dome would work back in the right direction power wise.
-
What kind of compression can you get with a flat top ?
-
Your combination is intriguing. I was wondering if a 1.888" Honda journal would have been necessary to obtain clearance, but you did it with 2". So do you think 4.6" stroke is feasible with a Honda journal? Would the further reduction in crank pin overlap yielded by such a combination be of too much of a concern, assuming a desire for longevity for the street with occasional track use (or even regular track use)?
Given a modern billet crank, where would you start to feel uncomfortable, regarding crank pin overlap, for a big inch street/strip engine? Would you recommend center counterweights?
I suspect it would lose 30-35 hp per point of compression. Probably around 800 power and 700 torque. I am thinking real serious about doing one like that for my Hondo Day Cruiser, so I may get to find out. A dish piston would be more efficient, so losing the dome would work back in the right direction power wise.
What would you estimate output to be if this engine was 10.5:1?
This particular one has 2.220 intake and 1.680 exhaust valves. I didn't intend to turn it real high, so I used the small valves to make torque where it wants to reside rpm-wise. That makes it real snappy with the inches and 13.5 static. If I was going to the end with it, more cam, a different set of angles on the valvejob, a 2.300 valve with a little more cross section in the port, would all have added up to quite a bit more power. It also would change the operating range. This engine will run for years reliably with a 7K shift point and 7300 through the traps.
The heads flow pretty good. Nevermind the numbers, as it is only one yardstick of several attributes that matter.
Blair, that's outstanding, from a engine that large. 1.67 HP per CI.
Can you tell us the valve size and how much the heads flowed.
We ran this unit last week. There was a little more in it, based on past info, but we ran out of time. Customer was looking for around 800 hp, and 700-ish torque, so when we got past there, we didn't beat it on it too hard. I had 31° timing in it, but it had a rather large dome by my standards, and a 72 cc chamber. I usually run much smaller chambers, with just a bump dome, but these heads migrated from another project, so more dome was needed. I think another 2.5 ° would have shown more power. I reckon they can test that in the vehicle.
Cubic inch: 535 (4.345 x 4.500)
Peak Horsepower: 893 at 6500 rpm
Peak Torque: 794 at 5100 rpm
Compression ratio: 13.5:1
Camshaft: .700 lift solid roller
Heads: BPE MR Race Pro Port Edelbrock
Manifold: BPE modified BBM Tunnel Wedge
Carbs: 940-ish cfm modified center squirters, inline with factory style linkage.
-
I don't think there is enough bearing surface area with the Honda. Even the hybrid bearing Honda with SBC width just doesn't have enough load patch area in my opinion. If it was a drag engine that saw VERY frequent teardown, the Honda might live. I like the 2" pin for durability. I just think that is about as far as I would go. I have several with more power and torque running long term with the 2" rods. As far as overlap, the Crower piece won't give up NA. It might become an issue with serious power adders, but the crank can take alot.
Eric, I can get past 14:1 with a flat top if I run the chamber program shallow and use a small chamber. This engine was a little bit of an unplanned mating of a rotating assembly and a pair of heads with the chamber at 72cc. I don't think the dome, designed like it is, hurt it bad, but it does hurt. A dish or a small "bump" dome will excite combustion better than just a flat top. Sometimes we make the valve relief an oval slot and then a small bump rather than a flat with plunge pockets.
-
Thank you for your thoughts!
I don't think there is enough bearing surface area with the Honda. Even the hybrid bearing Honda with SBC width just doesn't have enough load patch area in my opinion. If it was a drag engine that saw VERY frequent teardown, the Honda might live. I like the 2" pin for durability. I just think that is about as far as I would go. I have several with more power and torque running long term with the 2" rods. As far as overlap, the Crower piece won't give up NA. It might become an issue with serious power adders, but the crank can take alot.
Eric, I can get past 14:1 with a flat top if I run the chamber program shallow and use a small chamber. This engine was a little bit of an unplanned mating of a rotating assembly and a pair of heads with the chamber at 72cc. I don't think the dome, designed like it is, hurt it bad, but it does hurt. A dish or a small "bump" dome will excite combustion better than just a flat top. Sometimes we make the valve relief an oval slot and then a small bump rather than a flat with plunge pockets.
-
Always center counterweights with the long strokes if using a billet. Much better harmonics, and easier to balance. The economy forging from Scat can't go this long, and it doesn't have the big centers in the forging, but with billets, it is a machining operation. Lots of cases where the custom forged Scat is just fine......I use them frequently, but past 4.375, I sure do like the center counterweights.
-
I'm a little behind here, Blair had sent me these to post up.
(https://i.postimg.cc/5NG0m6pN/Blair-535.jpg) (https://postimages.org/) (https://i.postimg.cc/brVvWJhg/Blair-535-2.jpg) (https://postimages.org/)
(https://i.postimg.cc/Fs1zcjyB/Blair-535-3.jpg) (https://postimages.org/) (https://i.postimg.cc/NGdL5NHX/Blair-535-4.jpg) (https://postimages.org/)
-
WOW! That is impressive, can't hardly wait to see how mine turns out and what it makes .
-
Hard to read the dyno shot, but it shows well over 700 ft lbs of torque from 4500 to redline. Ports look fairly small, given the CI and intended use, so velocity must be pretty good, and the modified BBM TW must work pretty darned well with those heads.
Scott proved that the cam is streetable, so this engine could be driven on the street, if driven correctly, and the valvetrain was maintained in good order.
I'm curious how you got 900+ cfm out of the center squirters. What main body did you use, if you're willing to give up that info? How much power do you think a pair of standard 660s would give up?
-
Doug, not sure if these are what they started with, but Holley used to offer larger center squirter modes, around 850 cfm if I recall correctly.
-
Doug, not sure if these are what they started with, but Holley used to offer larger center squirter modes, around 850 cfm if I recall correctly.
I wasn't aware of that. Thanks, Rory.
I know Blair can work some magic on the 660s, but that's a big jump from 660 to 940. I don't see how a 660 main body could be worked to get that big of an improvement, and I'm not up on the aftermarket bodies that are available.
-
Original list number 4223 850 cfm center squirter.
-
I’d have to look it up, Chevrolet might have even put these on a Corvette 427, 1969ish?
-
It's a BBM iron block. No mods to the block for 4.500. I used a 2" rod journal, and you still have to clearance the back four rods so they don't bump the camshaft. About the same as a 4.375 with a 2.200 crankpin.
[/quote]
This made me wonder if it's possible to just "correct" the clearance issue with a smaller lobe profile and a larger rocker ratio for the same overall effect? Or is it essential to keep the cam size as is to have the shape/ramp to work as intended? At what ratio does it create too much angle on the pushrods?
I've never had the opportunity to build anything out of the ordinary so these builds will always create what if ideas.
-
I have 4 different List 850 center squirters on hand.
4224, 4543, are the most common.
Seems like I have maybe 15 or so on the shelf. Very cool, but a big step up from a 660.