Boosted 4V cobra motor vs Ls1
01-29-2007, 03:48 PM
#1
Boosted 4V cobra motor vs Ls1 Just wanted to ask if people know which motor would make more power and have the better curve given the ls1 has a forged shortblock and also the cobra motor. My brother is building his cobra with a single turbo to compete with me. We both would be trying to get the most power out of 91octane fuel. My heads are ported and am running a 222/224 .581 114 cam with 9.8:1 compression. Who do you guys guess will be able to lay down more power?
01-29-2007, 03:56 PM
#4
Depends on how much money he has. It cost alot to play with a 4V and build good power to hang with a LS1. This is coming from someone who has had a mustangs and nows owns a LS1. But if his pockets are deep then you can give you a run for your money, As a example a set of good 4V cams cost $1200.00 Badass custom cam will run you $400.00 on a LS1 
01-29-2007, 03:57 PM
#5
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Yes. Unless you have a power adder. He's able to run way over 600hp on a mostly stock motor, especially with a turbo setup. Is this an 03-04 motor? Either way, he has a serious advantage with that turbo.
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01-29-2007, 04:09 PM
#8
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The LS1 flows very very well for a pushrod motor. He isn't going to flow THAT MUCH better to make up for the fact that you have a larger engine (said without knowing much about what either of you have). I think it will come down to who has the biggest stones and turns up the boost.
01-29-2007, 05:35 PM
#10
He is going to use his factory cams and unported 4v heads which my ported 853 heads outflow his stock 4v heads. He is going to add forged pistons and rods, his car came from the factory with a forged crank. We both plan on running the same turbo a TC76MPS to make things somewhat fair. We are both going to turn up the boost as much as we can before detonation lays in. Both turbo kits will have tubular headers with FMIC. I am running the Street Killer kit. I think since I have the cubes advantage and heads that flow more air I should have the advantage?
01-29-2007, 05:58 PM
#13
Which Cobra does he have? 96-98, 99/01, 03/04? If its the latter version, I would have to say it could be pretty even (ONLY if he he has a solid or upgraded IRS) as you can cram alot of air into those engines.
01-29-2007, 06:05 PM
#14
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"edit" I was under the impression this was an 03-04 cobra motor swapped in... read on as if it were.
one thing I think you will be at a disadvantage at is the 4 valve cobra heads have a pent roof design which is a superior design for detonation suppression, this being said even though he is starting out at a 66 cubic inch disadvantage, his smaller bore and better chamber design with a centrally located spark plug will allow more boost to be run on lower octane fuel without detonation which may steal the advantage of shear volume back.
I think this will be a VERY interesting power build off.. I don't know which side of the fence I would hang my flag, obviously I am a GM man but I do think that his motor is going to be able to handle around 21+ psi on pump gas and a good tune with some moderate timing.. an LS1 is not gonna handle that kind of pressure on pump gas. so you may hit your detonation threshold long before him while he is continually able to turn the boost up. in either circumstance both of you better get your fuel systems up to snuff and have some solid tuning time done before you cut them loose on the dyno.
best of luck and keep us posted throughout!
Chris
one thing I think you will be at a disadvantage at is the 4 valve cobra heads have a pent roof design which is a superior design for detonation suppression, this being said even though he is starting out at a 66 cubic inch disadvantage, his smaller bore and better chamber design with a centrally located spark plug will allow more boost to be run on lower octane fuel without detonation which may steal the advantage of shear volume back.
I think this will be a VERY interesting power build off.. I don't know which side of the fence I would hang my flag, obviously I am a GM man but I do think that his motor is going to be able to handle around 21+ psi on pump gas and a good tune with some moderate timing.. an LS1 is not gonna handle that kind of pressure on pump gas. so you may hit your detonation threshold long before him while he is continually able to turn the boost up. in either circumstance both of you better get your fuel systems up to snuff and have some solid tuning time done before you cut them loose on the dyno.
best of luck and keep us posted throughout!
Chris
01-29-2007, 07:20 PM
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Originally Posted by lcvette
"edit" I was under the impression this was an 03-04 cobra motor swapped in... read on as if it were.
one thing I think you will be at a disadvantage at is the 4 valve cobra heads have a pent roof design which is a superior design for detonation suppression, this being said even though he is starting out at a 66 cubic inch disadvantage, his smaller bore and better chamber design with a centrally located spark plug will allow more boost to be run on lower octane fuel without detonation which may steal the advantage of shear volume back.
I think this will be a VERY interesting power build off.. I don't know which side of the fence I would hang my flag, obviously I am a GM man but I do think that his motor is going to be able to handle around 21+ psi on pump gas and a good tune with some moderate timing.. an LS1 is not gonna handle that kind of pressure on pump gas. so you may hit your detonation threshold long before him while he is continually able to turn the boost up. in either circumstance both of you better get your fuel systems up to snuff and have some solid tuning time done before you cut them loose on the dyno.
best of luck and keep us posted throughout!
Chris
one thing I think you will be at a disadvantage at is the 4 valve cobra heads have a pent roof design which is a superior design for detonation suppression, this being said even though he is starting out at a 66 cubic inch disadvantage, his smaller bore and better chamber design with a centrally located spark plug will allow more boost to be run on lower octane fuel without detonation which may steal the advantage of shear volume back.
I think this will be a VERY interesting power build off.. I don't know which side of the fence I would hang my flag, obviously I am a GM man but I do think that his motor is going to be able to handle around 21+ psi on pump gas and a good tune with some moderate timing.. an LS1 is not gonna handle that kind of pressure on pump gas. so you may hit your detonation threshold long before him while he is continually able to turn the boost up. in either circumstance both of you better get your fuel systems up to snuff and have some solid tuning time done before you cut them loose on the dyno.
best of luck and keep us posted throughout!
Chris
Being as it is a 98 cobra It will be close. Remember that motor LIVES for over 6500rpms and is most efficient their. Their are tonnes of people with stock cams in 4v's runnin DEEP into the 11's @/over 121mph N\A with 3.99 gear limitation in race NMRA trim @ 3100lbs It is going to come down to who isnt scared to leave a rod laying on the dyno or in the middle of the street. Good luck.
01-29-2007, 07:28 PM
#16
Can we just bet which will make most power on pumpgas? I'll take the ls1, past that it is going to depend on what other restrictons you guys put to the race. If he is allowed to run higher boost then you guys could make the same power. For some reason I want to say the 4v motor can make more peak hp, it always seems like smaller ci motors make alittle more power then big ci motors on the same turbo.
01-29-2007, 08:26 PM
#18
the cobra has a ton less valvetrain weight and will be able to rev way higher then an LS1
i'm not sure about turbo's, but a few weeks ago there was a C5R block 427 corvette at my buddys shop with a vortech T-trim blower on it that was a manual and put down like 500/500 somewhere around there, i forget the exacts. anyways, then my buddy's '98 cobra was on the rollers next, it has been swapped to an auto, it's a stroker 5.1ish motor with custom cams and dished pistons around 8.5 cr. it also had a vortech T-trim blower and through his auto it put down 570hp and i forget the torque, but being a smaller motor with the same blower and through an unlocked auto, the cobra was spinning a lot higher and making a lot more power. given the vette was running like 12 psi, and the cobra was pushing 25psi if memory serves me
i would have to say there's way too many variables,
it all comes down to the golden rule...he with the most gold rules!
i'm not sure about turbo's, but a few weeks ago there was a C5R block 427 corvette at my buddys shop with a vortech T-trim blower on it that was a manual and put down like 500/500 somewhere around there, i forget the exacts. anyways, then my buddy's '98 cobra was on the rollers next, it has been swapped to an auto, it's a stroker 5.1ish motor with custom cams and dished pistons around 8.5 cr. it also had a vortech T-trim blower and through his auto it put down 570hp and i forget the torque, but being a smaller motor with the same blower and through an unlocked auto, the cobra was spinning a lot higher and making a lot more power. given the vette was running like 12 psi, and the cobra was pushing 25psi if memory serves me
i would have to say there's way too many variables,
it all comes down to the golden rule...he with the most gold rules!
01-29-2007, 08:43 PM
#20
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Originally Posted by SS4Matt
the cobra has a ton less valvetrain weight and will be able to rev way higher then an LS1
i'm not sure about turbo's, but a few weeks ago there was a C5R block 427 corvette at my buddys shop with a vortech T-trim blower on it that was a manual and put down like 500/500 somewhere around there, i forget the exacts. anyways, then my buddy's '98 cobra was on the rollers next, it has been swapped to an auto, it's a stroker 5.1ish motor with custom cams and dished pistons around 8.5 cr. it also had a vortech T-trim blower and through his auto it put down 570hp and i forget the torque, but being a smaller motor with the same blower and through an unlocked auto, the cobra was spinning a lot higher and making a lot more power. given the vette was running like 12 psi, and the cobra was pushing 25psi if memory serves me
i would have to say there's way too many variables,
it all comes down to the golden rule...he with the most gold rules!
i'm not sure about turbo's, but a few weeks ago there was a C5R block 427 corvette at my buddys shop with a vortech T-trim blower on it that was a manual and put down like 500/500 somewhere around there, i forget the exacts. anyways, then my buddy's '98 cobra was on the rollers next, it has been swapped to an auto, it's a stroker 5.1ish motor with custom cams and dished pistons around 8.5 cr. it also had a vortech T-trim blower and through his auto it put down 570hp and i forget the torque, but being a smaller motor with the same blower and through an unlocked auto, the cobra was spinning a lot higher and making a lot more power. given the vette was running like 12 psi, and the cobra was pushing 25psi if memory serves me
i would have to say there's way too many variables,
it all comes down to the golden rule...he with the most gold rules!
back to the poster, i think you will have the most "useable" power.