Converting An Ls7 To 6 Litres With A 96.9mm Bore
02-10-2007, 07:01 AM
#22
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I stand corrected 
- I was only told this 2 days ago - new terminoligy to me - thanks for the reply Katech 
Katech - do you mind me asking - whats the typical weight of a dressed LS7 race motor.
- I was only told this 2 days ago - new terminoligy to me - thanks for the reply Katech Katech - do you mind me asking - whats the typical weight of a dressed LS7 race motor.
02-10-2007, 10:05 AM
#23
Originally Posted by knightec
I stand corrected - I was only told this 2 days ago - new terminoligy to me - thanks for the reply Katech
Katech - do you mind me asking - whats the typical weight of a dressed LS7 race motor.
- I was only told this 2 days ago - new terminoligy to me - thanks for the reply Katech Katech - do you mind me asking - whats the typical weight of a dressed LS7 race motor.
02-10-2007, 03:14 PM
#25
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Yeh, really deep but you can appreciate why. Katech, have done so much work and given their investment in market position it's hardly surprising they don't give away freebies.
Mike.
Mike.
02-10-2007, 08:01 PM
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Originally Posted by knightec
I'm assuming its got little if no overlap, as there will be a big depression in the intake system due to the air restrictors - which you dont want pulling on the exhaust with loads of overlap
02-11-2007, 06:03 AM
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Originally Posted by J-Rod
For information on what I'm talking about look at the Sun Trust Pontiac Daytona Prototype running in the Grand American Rolex Series. That motor has been limited down to as little as 5.0L, and 7100 RPMs. In 2005 for instance, Pontiac led 81% of the laps in the series.
The GM Caddillac in Speed GT went from back of the pack to 2nd place in literally a couple of laps. The drivers were just loafing around. They ended up with huge restrictors, and still made crazy power. The new GM racing lifters that you are seeing came directly as a result of GM making parts that would last at extedned periods of high RPM operation.
The GM Caddillac in Speed GT went from back of the pack to 2nd place in literally a couple of laps. The drivers were just loafing around. They ended up with huge restrictors, and still made crazy power. The new GM racing lifters that you are seeing came directly as a result of GM making parts that would last at extedned periods of high RPM operation.
Seriously I think J-rod has nailed your question on the restrictor class and the LSx motor.
02-11-2007, 10:12 AM
#32
Originally Posted by knightec
Katech - do you mind me asking - whats the typical weight of a dressed LS7 race motor.
J-Rod,
The Protoype motors also state in the rules that they are limited to a 3.900" bore. Those motors end up being the most tweaked LS1 production based motors out there. Probably more so than the Katech units that they build for the CTS-V. The C5/6R program is a whole different deal, none of the parts in that motor are even production based, even though the LS7 is a derivitive of it.
knightec,
If you were going ***** out with no $$$ limit a C5R head would be a good place to start since the port without CNC work is very small to start from. You would need a custom fabbed intake and at least a 4.0" bore, but match that up to a stock stroke crank and you are good to go.
Bret
02-12-2007, 05:12 AM
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guys, thanks for your great replies, I have now learnt a great deal about the LS heads available to me......just to throw some light why I'm headed down this troute, two reasons:-
1) V8 2-valve push-rod LMP1 motors have been tried before by chrysler (John Caldwell), and by Panoz (Elan technologies) - in short, they failed on track.......these motors have been NASCAR motors, derived from thier 358" (5.8 litre) base capacity........they have been very short stroke, wide bore motors, as per the NASAR engine rules around max bore and valve spacing........I know the cross-sectional area of the NASCAR restrictor plates compare well to the LeMans restrictors - but it just dosent work like that......the lemans motors just dont rev like their Nascar alternatives......the 6.0 lemans restrictors, really limit revs to about 7500rpm.....and in short the motors listed above dont make the power or torque of the competitors, as they cant rev as high as they would like, Chrysler were quoting 590bhp, Panoz were 620bhp......their on-track performances would appear to indicate this too - in otherwords - they were not competitive motors......in todays world you need to be in the region of 650bhp for a good LMP1 motor........hence to do this with a 6.0 2-valve motor, the bore and stroke are important factors in making low down power before the restrictors take effect at high revs.
2) 2.0 Litre F3 motors are a classic example of how to make a good restrictor motor, very long strokes of about 93mm with bores of about 82.5mm.......they make about 215bhp at 5500rpm.......which is well before the restrictor takes effect = more area under the power curve......yes all F3 motors are 4-valve heads - but the principle is still the same for a any valve amount & layout........F3 valves are heavily shrouded, but still flow OK
I agree that the small bore I am initially evaluating (96.9mm) may be pushing it a bit......I dare say I may have to back it off a little and start to consider an equal bore and stroke - otherwise known as square.......the long stroke is a fundamental part of producing low down power.......this is not me speculating - its been proven in many forms of motorsport.........the main problem here is that V8 pushrod motors follow a traditional tuning route derived from the likes of Nascar, drag racing, outlaws etc......the ACO regulations for a 6.0 2-valve LMP1 LeMans engine are a different ball game - as John Caldwell and Panoz found out the hard way.
1) V8 2-valve push-rod LMP1 motors have been tried before by chrysler (John Caldwell), and by Panoz (Elan technologies) - in short, they failed on track.......these motors have been NASCAR motors, derived from thier 358" (5.8 litre) base capacity........they have been very short stroke, wide bore motors, as per the NASAR engine rules around max bore and valve spacing........I know the cross-sectional area of the NASCAR restrictor plates compare well to the LeMans restrictors - but it just dosent work like that......the lemans motors just dont rev like their Nascar alternatives......the 6.0 lemans restrictors, really limit revs to about 7500rpm.....and in short the motors listed above dont make the power or torque of the competitors, as they cant rev as high as they would like, Chrysler were quoting 590bhp, Panoz were 620bhp......their on-track performances would appear to indicate this too - in otherwords - they were not competitive motors......in todays world you need to be in the region of 650bhp for a good LMP1 motor........hence to do this with a 6.0 2-valve motor, the bore and stroke are important factors in making low down power before the restrictors take effect at high revs.
2) 2.0 Litre F3 motors are a classic example of how to make a good restrictor motor, very long strokes of about 93mm with bores of about 82.5mm.......they make about 215bhp at 5500rpm.......which is well before the restrictor takes effect = more area under the power curve......yes all F3 motors are 4-valve heads - but the principle is still the same for a any valve amount & layout........F3 valves are heavily shrouded, but still flow OK
I agree that the small bore I am initially evaluating (96.9mm) may be pushing it a bit......I dare say I may have to back it off a little and start to consider an equal bore and stroke - otherwise known as square.......the long stroke is a fundamental part of producing low down power.......this is not me speculating - its been proven in many forms of motorsport.........the main problem here is that V8 pushrod motors follow a traditional tuning route derived from the likes of Nascar, drag racing, outlaws etc......the ACO regulations for a 6.0 2-valve LMP1 LeMans engine are a different ball game - as John Caldwell and Panoz found out the hard way.
02-12-2007, 12:59 PM
#34
So are you trying to design a motor for a class? If so what class? What rules.
The C6R motor does extremely well for it's class with restrictiors, if you are trying to race in LMP1 well maybe you should start looking into turning the GM Durmax to higher RPM than worrying about a LS1 motor. The rules tell you what motors they want to see win.
Bret
The C6R motor does extremely well for it's class with restrictiors, if you are trying to race in LMP1 well maybe you should start looking into turning the GM Durmax to higher RPM than worrying about a LS1 motor. The rules tell you what motors they want to see win.
Bret
02-12-2007, 03:01 PM
#35
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Originally Posted by Steve Bryant
Is this for a school project or something of the sort?
Steve
02-12-2007, 04:50 PM
#36
Me too Steve. I don't think people can really grasp the different schools of race engines between the US and Europe. They almost always have a clean sheet of paper design. The majority of US racing motors are based of off a production piece that is highly modified. Up until the days of 18° heads there wasn't much in terms of GM Racing parts for motors.
A clean paper design allows you to do so much more in every aspect of the motor. Things that help the CAR not the motor just make more power, like rigidity or CG.
Bret
A clean paper design allows you to do so much more in every aspect of the motor. Things that help the CAR not the motor just make more power, like rigidity or CG.
Bret
02-13-2007, 02:22 AM
#38
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Originally Posted by knightec
its a feasability study for a 6.0 race motor for endurance racing in open top sports prototype (leMans) running air restrictors....
Steve Bryant - you should have read the full thread before saying that!........ but saying that I know it can be easy to miss things the longer a thread gets......read my second post quoted above and all will be revealed.......as for a school project......I'm an engine design consultant, check out my website www.knightecengineering.com, needless to say a no frills site - I'm a one man band who sells my engine design, development and production knowledge to the production and race engine industry........the only reason I came to this site was to learn about the LS cylinder head options as I stated in the original post.
02-13-2007, 06:46 AM
#39
Knighttec, see where your coming form now!
if you where designing a motor for a company would you have one made from biliet or go for a production block?
thanks Chris.
PS, dont worry about some people having a go on here. alot dont like to see outside the box!
if you where designing a motor for a company would you have one made from biliet or go for a production block?
thanks Chris.
PS, dont worry about some people having a go on here. alot dont like to see outside the box!
02-13-2007, 07:41 AM
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as I said above - because the team owner who is interested in the concept has 6 LS7 crate motors sitting on his workshop floor!......the heads, pistons & rods, liners inlet system are of no use, but the block, crank, main caps etc are ideal from what I can see......the engine needs to be fully stressed, or at least semi stressed, and the LS7 bottom end is ideal for this.
just to add some more weight to why a 4"+ type bore size of motor will fail as an LMP1 engine.......heres how John Caldwell from CDi specced the Chrysler-Mopar LMP1 engine from 2000-2001, he is a well respected engine builder and had serious money behind the project ,as it was a works deal with a Dallara chassis, OK it finished 4th at Lemans in 2001, but thats the highlight of the engines poor racing career:-
Engine Builder: JOHN CALDWELL CDI
Manufacturer: MOPAR
Bore: 105.5mm
Stroke: 85.59mm
Displacement: 365ci (5998cc)
Weight: 375lbs (170Kg)
Induction: CARBON FIBER INTAKE MANIFOLD WITH EFI
Heads: CUSTOM RAISED PORT W8 HEADS FOR LEMANS ONLY
Block: MOPAR ALUMINUM MADE FOR LEMANS
Main Caps: PROGRAMS BILLET CROSS BOLTED
Crankshaft: LA ENTERPRISES BILLET 3.37 STROKE
Connecting Rods: CARRILLO
Pistons: CP CUSTOM
Camshaft: LSM
Valves: 2.18 1.625 DELWEST TITANIUM
Valve Train: JESEL AND T&D
Horsepower: 585bhp with two 33.1mm restrictors
Torque: 500-550 lb-ft (678-746NM)
the Panoz engine was not much different to the above spec, all I have are the Panoz performance figures 620bhp@7200rpm, and 538lb-ft @6500, and that it was based on an aluminium version of the ali clevland head, ali windsor block......on the torque figures alone - both engines were failures - the strokes were way too short.
just to add some more weight to why a 4"+ type bore size of motor will fail as an LMP1 engine.......heres how John Caldwell from CDi specced the Chrysler-Mopar LMP1 engine from 2000-2001, he is a well respected engine builder and had serious money behind the project ,as it was a works deal with a Dallara chassis, OK it finished 4th at Lemans in 2001, but thats the highlight of the engines poor racing career:-
Engine Builder: JOHN CALDWELL CDI
Manufacturer: MOPAR
Bore: 105.5mm
Stroke: 85.59mm
Displacement: 365ci (5998cc)
Weight: 375lbs (170Kg)
Induction: CARBON FIBER INTAKE MANIFOLD WITH EFI
Heads: CUSTOM RAISED PORT W8 HEADS FOR LEMANS ONLY
Block: MOPAR ALUMINUM MADE FOR LEMANS
Main Caps: PROGRAMS BILLET CROSS BOLTED
Crankshaft: LA ENTERPRISES BILLET 3.37 STROKE
Connecting Rods: CARRILLO
Pistons: CP CUSTOM
Camshaft: LSM
Valves: 2.18 1.625 DELWEST TITANIUM
Valve Train: JESEL AND T&D
Horsepower: 585bhp with two 33.1mm restrictors
Torque: 500-550 lb-ft (678-746NM)
the Panoz engine was not much different to the above spec, all I have are the Panoz performance figures 620bhp@7200rpm, and 538lb-ft @6500, and that it was based on an aluminium version of the ali clevland head, ali windsor block......on the torque figures alone - both engines were failures - the strokes were way too short.
Last edited by knightec; 02-13-2007 at 07:51 AM.