245cc heads on 347
08-11-2013, 08:46 AM
#23
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Rectangle port heads have a different CSA.
CSA is what matters. Not port volume. That's why the Lingenfelter heads do well with their 250cc port and 2.08" valves on stock LS1s. Hell, their flow numbers are atrocious as well but they make power and torque.
CSA = cross-sectional area. You can make power and torque with a big port if it keeps velocity up.
CSA is what matters. Not port volume. That's why the Lingenfelter heads do well with their 250cc port and 2.08" valves on stock LS1s. Hell, their flow numbers are atrocious as well but they make power and torque.
CSA = cross-sectional area. You can make power and torque with a big port if it keeps velocity up.
In a word Christian - no.
Remember the grief we both took from the "gurus" on here with your original LS6 combination? Blew up a lot of the internet folklore with your results so no, I won't be doing any explaining of anything on here. Besides, there is Speedtalk and YellowBullet for unfiltered information.
Glad you made it out alive! The YB can chew people up whole!
08-11-2013, 08:52 AM
#24
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OP, my apologies, I took this off the main topic, I went that way, b/c with the 245's port velocity and CSA will both be the main issues of that port on the small bore, just like the small bore LS3's.
08-11-2013, 05:05 PM
#26
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Ok, so I've been on this worm hole all day since its 102* out today, and outdoor activities can lead to bad times...
Here are a couple of articles/tech tips that I've looked over today.
The first, is from Chevy high performance. It's an old article (not too old), but provides great insight in the wonder of cylinder head design.
http://www.chevyhiperformance.com/te...n/viewall.html
The second is actually off of Reher Morrison's site.
It's their Buying cylinder heads tips and it has GREAT insight! After looking it over read note at the bottom and read their tech talk #6,16, and 70. They are great. Also, everyone of their tech talk blog post are awesome. Insight to making ultimate power!
http://rehermorrison.com/product/buy...tips-and-info/
Here are a couple of articles/tech tips that I've looked over today.
The first, is from Chevy high performance. It's an old article (not too old), but provides great insight in the wonder of cylinder head design.
http://www.chevyhiperformance.com/te...n/viewall.html
The second is actually off of Reher Morrison's site.
It's their Buying cylinder heads tips and it has GREAT insight! After looking it over read note at the bottom and read their tech talk #6,16, and 70. They are great. Also, everyone of their tech talk blog post are awesome. Insight to making ultimate power!
http://rehermorrison.com/product/buy...tips-and-info/
09-14-2013, 06:14 PM
#28
What cam do you think would work well with these small bore heads? I am running the bsp small bores and I just randomly tried a 230/238 cam and it doesn't pull as hard as the 224/230 cam I had in there prior.
Seems smaller cam is the way to go, but curious what the gurus think.
Seems smaller cam is the way to go, but curious what the gurus think.
09-14-2013, 07:20 PM
#29
I suggested a 222/234 111+4 in the BSP thread. I use that cam in G8's and 5th Gen Camaro's for guys that want a strong powerband across the board and great torque.
These large intake port volumes/valves do not need near the intake duration as the smaller port volumes of a cathedral port head. They do like exhaust duration though and contrary to internet belief the square port heads like overlap.
These large intake port volumes/valves do not need near the intake duration as the smaller port volumes of a cathedral port head. They do like exhaust duration though and contrary to internet belief the square port heads like overlap.
09-14-2013, 09:01 PM
#30
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I suggested a 222/234 111+4 in the BSP thread. I use that cam in G8's and 5th Gen Camaro's for guys that want a strong powerband across the board and great torque.
These large intake port volumes/valves do not need near the intake duration as the smaller port volumes of a cathedral port head. They do like exhaust duration though and contrary to internet belief the square port heads like overlap.
These large intake port volumes/valves do not need near the intake duration as the smaller port volumes of a cathedral port head. They do like exhaust duration though and contrary to internet belief the square port heads like overlap.
09-15-2013, 03:04 AM
#31
To an extent. You must look at many different things to determine exactly how much overlap a cylinder head wants. Many times though that information isn't given to a person like myself or cannot be provided because the customer doesn't know it themselves.
09-15-2013, 09:00 PM
#32
Thanks 427zm...those are some good reads. In fact the very first point RMS
made was clearance of the valve to the bore (one of the guys in the other
read said the In. was more important than the Ex.) so even though the OPs
heads would fit and could be made to work for an elevated rpm application, I
still can't see the 2.08 valve filling the cylinder without undue turbulance
which could lessen the BSFC. The new LT1 engine changes everything since
with direct injection the fuel atomization is nearly perfect at all times and
now the runner no longer needs to have tumble and swirl to promote mix-
ture homogeneaity. A whole new animal that freaks like Martin get to play
with and tweak like needle junkies......
made was clearance of the valve to the bore (one of the guys in the other
read said the In. was more important than the Ex.) so even though the OPs
heads would fit and could be made to work for an elevated rpm application, I
still can't see the 2.08 valve filling the cylinder without undue turbulance
which could lessen the BSFC. The new LT1 engine changes everything since
with direct injection the fuel atomization is nearly perfect at all times and
now the runner no longer needs to have tumble and swirl to promote mix-
ture homogeneaity. A whole new animal that freaks like Martin get to play
with and tweak like needle junkies......
09-15-2013, 09:13 PM
#33
I suggested a 222/234 111+4 in the BSP thread. I use that cam in G8's and 5th Gen Camaro's for guys that want a strong powerband across the board and great torque.
These large intake port volumes/valves do not need near the intake duration as the smaller port volumes of a cathedral port head. They do like exhaust duration though and contrary to internet belief the square port heads like overlap.
These large intake port volumes/valves do not need near the intake duration as the smaller port volumes of a cathedral port head. They do like exhaust duration though and contrary to internet belief the square port heads like overlap.
would this be the custom cam option on your site?
How far can this cam carry the power? In my setup I am able to spin as high as 7200, but generally speaking, I only spin that high through the traps so I can stay in 3rd. Otherwise I shift around 6800.
09-15-2013, 09:38 PM
#34
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Thanks 427zm...those are some good reads. In fact the very first point RMS
made was clearance of the valve to the bore (one of the guys in the other
read said the In. was more important than the Ex.) so even though the OPs
heads would fit and could be made to work for an elevated rpm application, I
still can't see the 2.08 valve filling the cylinder without undue turbulance
which could lessen the BSFC. The new LT1 engine changes everything since
with direct injection the fuel atomization is nearly perfect at all times and
now the runner no longer needs to have tumble and swirl to promote mix-
ture homogeneaity. A whole new animal that freaks like Martin get to play
with and tweak like needle junkies......
made was clearance of the valve to the bore (one of the guys in the other
read said the In. was more important than the Ex.) so even though the OPs
heads would fit and could be made to work for an elevated rpm application, I
still can't see the 2.08 valve filling the cylinder without undue turbulance
which could lessen the BSFC. The new LT1 engine changes everything since
with direct injection the fuel atomization is nearly perfect at all times and
now the runner no longer needs to have tumble and swirl to promote mix-
ture homogeneaity. A whole new animal that freaks like Martin get to play
with and tweak like needle junkies......
09-15-2013, 10:23 PM
#35
I would expect a 4600-4800rpm torque peak and a 6200-6400rpm horsepower peak with your cylinder heads and intake manifold combination. With the exhaust events the camshaft has, it should carry power to well over 6600-6800rpm.
With the size of the port and valve, the power will carry far into the RPM range after it peaks due to the exhaust opening of the camshaft versus the intake valve closing. I wouldn't see any reason why it wouldn't possibly even carry to 7000rpm.
09-15-2013, 11:02 PM
#36
Yes it would be a custom camshaft. I can grind it on several different combinations of lobes as well to match what you would like out of the valve train.
I would expect a 4600-4800rpm torque peak and a 6200-6400rpm horsepower peak with your cylinder heads and intake manifold combination. With the exhaust events the camshaft has, it should carry power to well over 6600-6800rpm.
With the size of the port and valve, the power will carry far into the RPM range after it peaks due to the exhaust opening of the camshaft versus the intake valve closing. I wouldn't see any reason why it wouldn't possibly even carry to 7000rpm.
I would expect a 4600-4800rpm torque peak and a 6200-6400rpm horsepower peak with your cylinder heads and intake manifold combination. With the exhaust events the camshaft has, it should carry power to well over 6600-6800rpm.
With the size of the port and valve, the power will carry far into the RPM range after it peaks due to the exhaust opening of the camshaft versus the intake valve closing. I wouldn't see any reason why it wouldn't possibly even carry to 7000rpm.
09-18-2013, 12:49 PM
#38
What cam do you think would work well with these small bore heads? I am running the bsp small bores and I just randomly tried a 230/238 cam and it doesn't pull as hard as the 224/230 cam I had in there prior.
Seems smaller cam is the way to go, but curious what the gurus think.
Seems smaller cam is the way to go, but curious what the gurus think.
09-18-2013, 12:51 PM
#39
Did you get them milled any, running a thinner head gasket or what is your static compression? The larger cam didn't help your DCR and the larger ports have shown to be lazier down low (<3k rpm) than a cathedral all other things equal. What were the torque differences on the dyno?
I didn't save the graph, but it picked up 40 ft/lbs pretty much everywhere, but that was with the 224/230 cam. I did not re dyno with the bigger cam. I got no track times with the smaller cam either, so I can't compare.
09-26-2013, 08:36 AM
#40
I ran a 250+cc port on a 383 LT1 with a middle of the road solid roller and a 7000 rpm limit.
I got the same crap from everyone, it will be a dog, heads too big, too much cam, can't drive that on the street...the whole line of crap.
Car ran 10.50's@126 mph with a 4.11 gear and a 3500 converter in a 3600lb car on pumpgas.....guessing about 585 hp or so.
Put some compression in the car to help it's torque and run the head, don't listen to all the regurgitated internet rhetoric.
I got the same crap from everyone, it will be a dog, heads too big, too much cam, can't drive that on the street...the whole line of crap.
Car ran 10.50's@126 mph with a 4.11 gear and a 3500 converter in a 3600lb car on pumpgas.....guessing about 585 hp or so.
Put some compression in the car to help it's torque and run the head, don't listen to all the regurgitated internet rhetoric.
