LT4 heads/intake limitations
With a mid 11 sec. goal you can get away with a nice Ai 190cc or LE2 package and keep things on a budget. I have a mild cam and the LE2's and I run mid 11's with that. The car is a street/strip car and still has alot of potential in it with more gear, suspension etc. etc. So basically by being limited with the stock bottom end and whatnot I would personally get an Ai 190cc or LE2 package and just have fun with that. When it gets to the point that you eventually want more then tear into the motor build a stroker and run some better heads.
With a mid 11 sec. goal you can get away with a nice Ai 190cc or LE2 package and keep things on a budget. I have a mild cam and the LE2's and I run mid 11's with that. The car is a street/strip car and still has alot of potential in it with more gear, suspension etc. etc. So basically by being limited with the stock bottom end and whatnot I would personally get an Ai 190cc or LE2 package and just have fun with that. When it gets to the point that you eventually want more then tear into the motor build a stroker and run some better heads.
Larry
Stock LT4 heads from SDPC run close to $1500 for heads alone. Then you need to get really lucky to score a GM LT4 intake for less than $600, modify an LT1 intake to fit the heads (usually, some may work without mods), or buy an Edelbrock LT4 intake. Quite a hefty price tag to run a stock head. Looks like the LE2 package, with cam, runs $1600. Tack on another $200 if you want your intake ported.
Larry
Larry
So it really is more effective to port the stockers, will come out to about the same money only a good bit more power.
I still don't see the RESULTS in actual practice.
I stand by my opinion that LT4 heads are best in bench racer land.
I respect GIZMO's opinion BUT he looks at things from a different perspective, he spends as much blueprinting heads as the rest of us do porting. He is in a strict rules class that will not allow porting so he is always looking for best as cast.
As cast vs as cast yes the LT4s have an advantage.
Maybe it will help if I say something good about the LT4s, the valves are awesome, if you could get them separate at a reasonable price I would strongly consider using them.
I stand by my opinion that LT4 heads are best in bench racer land.
I respect GIZMO's opinion BUT he looks at things from a different perspective, he spends as much blueprinting heads as the rest of us do porting. He is in a strict rules class that will not allow porting so he is always looking for best as cast.
As cast vs as cast yes the LT4s have an advantage.
Maybe it will help if I say something good about the LT4s, the valves are awesome, if you could get them separate at a reasonable price I would strongly consider using them.
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Verdad Gallardo In my head you would think a LT4 with some bowl work and a good valvejob would perform close to a LE1/1.5 head. Or am I in left field here?
I still don't see the RESULTS in actual practice.
I stand by my opinion that LT4 heads are best in bench racer land.
I respect GIZMO's opinion BUT he looks at things from a different perspective, he spends as much blueprinting heads as the rest of us do porting. He is in a strict rules class that will not allow porting so he is always looking for best as cast.
As cast vs as cast yes the LT4s have an advantage.
Maybe it will help if I say something good about the LT4s, the valves are awesome, if you could get them separate at a reasonable price I would strongly consider using them.
I stand by my opinion that LT4 heads are best in bench racer land.
I respect GIZMO's opinion BUT he looks at things from a different perspective, he spends as much blueprinting heads as the rest of us do porting. He is in a strict rules class that will not allow porting so he is always looking for best as cast.
As cast vs as cast yes the LT4s have an advantage.
Maybe it will help if I say something good about the LT4s, the valves are awesome, if you could get them separate at a reasonable price I would strongly consider using them.
Would you, by any chance, be an engineer? I love racing engineers.
Last edited by Ed Wright; Feb 12, 2010 at 11:03 AM.
Considering track and air conditions, what are you looking for?
You didn't answer my questions?
Trying to compare cars running at different parts of the country is even dumber than comparing dyno numbers from different dynos in different parts of the country.
You didn't answer my questions?
Trying to compare cars running at different parts of the country is even dumber than comparing dyno numbers from different dynos in different parts of the country.
Last edited by Ed Wright; Feb 12, 2010 at 11:23 AM.
and you guys are not answering mine.
You want to focus on weather but dismiss your couple points more compression and what 150lbs less weight. Yes weather is absolutely a factor but so is weight and compression and I think you posted you were spinning about 500rpms higher than Rick.
Here is an OLD discussion on the topic.
https://ls1tech.com/forums/5926393-post23.html 14:1 compression to Rick's 11.7 with the 200cc heads.
https://ls1tech.com/forums/5933110-post33.html
Here you say not worth it below 7000rpm limitation of the pcm and that your setup peaks 500rpm later.
I will give you that it looks like is spinning past well 7000rpms then yeah LT4 start to look like a good starting point. How many of us are looking to do that? The OPs goal of 11s and no talk of aftermarket injection would seem to mean even by your own past statements the LT4s are NOT what he should be looking at.
Actually the rpms thing is another area where GIZMO's experience is vastly different from what most of us do, another case were he is using a LOT of rpm to go fast. It absolutely works, but FEW of us drop the coin on aftermarket injection.
Most of us run 350-383ci motors and hold them below 7100rpms. Maybe the LT4s are better above those thresholds, but then why stop there? SB2.2s are better yet if looking to spin even higher.
My point is I am trying to steer the guy towards parts that will work for his intended application, not bench racing a larger motor turning 1000rpms higher.
You want to focus on weather but dismiss your couple points more compression and what 150lbs less weight. Yes weather is absolutely a factor but so is weight and compression and I think you posted you were spinning about 500rpms higher than Rick.
Here is an OLD discussion on the topic.
https://ls1tech.com/forums/5926393-post23.html 14:1 compression to Rick's 11.7 with the 200cc heads.
https://ls1tech.com/forums/5933110-post33.html
Here you say not worth it below 7000rpm limitation of the pcm and that your setup peaks 500rpm later.
I will give you that it looks like is spinning past well 7000rpms then yeah LT4 start to look like a good starting point. How many of us are looking to do that? The OPs goal of 11s and no talk of aftermarket injection would seem to mean even by your own past statements the LT4s are NOT what he should be looking at.
Actually the rpms thing is another area where GIZMO's experience is vastly different from what most of us do, another case were he is using a LOT of rpm to go fast. It absolutely works, but FEW of us drop the coin on aftermarket injection.
Most of us run 350-383ci motors and hold them below 7100rpms. Maybe the LT4s are better above those thresholds, but then why stop there? SB2.2s are better yet if looking to spin even higher.
My point is I am trying to steer the guy towards parts that will work for his intended application, not bench racing a larger motor turning 1000rpms higher.
I'll answer that after you answer how weather is a big deal but 2 points of compression and over 100lbs is meaningless.
As I just said in another thread, people like to attack the other GUY rather than his argument. That is what you are doing. Try and correct me on DATA.
FATBOY has taken another approach trying to put words in my mouth, never said cylinder head dictates rpm. It does play into it, as does cam duration and timing, intake manifold and header selection etc.
Again I push you back to DATA and results, if the LT4s are where it is at put up examples and results, without that you are just benchracing.
As I just said in another thread, people like to attack the other GUY rather than his argument. That is what you are doing. Try and correct me on DATA.
FATBOY has taken another approach trying to put words in my mouth, never said cylinder head dictates rpm. It does play into it, as does cam duration and timing, intake manifold and header selection etc.
Again I push you back to DATA and results, if the LT4s are where it is at put up examples and results, without that you are just benchracing.
Because you can only go as fast as your heads allow. Your heads will only go up to a certain point before they reach their ceiling and drop off.
Honestly I think the LT4's will outperform the LT1's if done right, BUT the price to do so is not worth it for someone on a low budget. If you can get LT4 heads, and an acceptable intake for a good price, go for it and you have a good base to start with. Send em to LE and build from there. If you cant get the stock LT4 heads for less that say 400...stick with the stock LT1 heads, send THEM to LE, and work with that.
LT4's for 500 plus intake for 500 (both just estimates) sent to LE for portwork for 1300 for the LE2 package will put you at 2300 bucks already. Then you still need your cam, RR's, pushrods, gaskets, shipping costs, etc.
LT1's you already have, Sent to LE for portwork for 1300 for the LE2 package, and you only spend 1300....then you have more to play with to build on. Get your new RR's, your cam, pay for shipping, new pushrods, gaskets, fluids, etc and your STILL below 2300.
It is up to your budget. If you can afford the LT4 LE2 setup, do it...you will have a more powerful head with more potential just get with Ed Wright or someone with LT4 experience to find out what works or doesnt, and build from their blueprint. If you CANT afford the LT4 LE2 setup, go with the LT1 LE2 which is proven for 400+ EASILY, and enjoy!
Just my .02
Honestly I think the LT4's will outperform the LT1's if done right, BUT the price to do so is not worth it for someone on a low budget. If you can get LT4 heads, and an acceptable intake for a good price, go for it and you have a good base to start with. Send em to LE and build from there. If you cant get the stock LT4 heads for less that say 400...stick with the stock LT1 heads, send THEM to LE, and work with that.
LT4's for 500 plus intake for 500 (both just estimates) sent to LE for portwork for 1300 for the LE2 package will put you at 2300 bucks already. Then you still need your cam, RR's, pushrods, gaskets, shipping costs, etc.
LT1's you already have, Sent to LE for portwork for 1300 for the LE2 package, and you only spend 1300....then you have more to play with to build on. Get your new RR's, your cam, pay for shipping, new pushrods, gaskets, fluids, etc and your STILL below 2300.
It is up to your budget. If you can afford the LT4 LE2 setup, do it...you will have a more powerful head with more potential just get with Ed Wright or someone with LT4 experience to find out what works or doesnt, and build from their blueprint. If you CANT afford the LT4 LE2 setup, go with the LT1 LE2 which is proven for 400+ EASILY, and enjoy!
Just my .02
(Did I really just state that on open forum?!!)