Cathedral vs Ls3 test
This thread keeps jumping from street setups, to race setups, which are two entirely different animals. You guys cannot compare square/cathedral street setups to square/cathedral race setups. This discussion is a waste of time.
Way more bad combos than good combos out there. Don't build off the bad ones....build off the good ones. But combos like that is why i recommend guys run 11s with bolt ons before camming/building these cars. The oe engines are very powerful if you get everything else around them working.
But as far as that combo goes i would start by chucking that ls3 intake and 90mm tb for a 408.
Just because someone bought a bunch of suspension parts don't mean it's better either.....sometimes it just means they bought a bunch of suspension parts.
But as far as that combo goes i would start by chucking that ls3 intake and 90mm tb for a 408.
Just because someone bought a bunch of suspension parts don't mean it's better either.....sometimes it just means they bought a bunch of suspension parts.
Well those combos happen quite often. Not go call no names buts its a few on this site.... its not just one guy. I went to LS fest and seen one in person. Nice car and all but it it was 11.4s at 122 with a T56 and a Quick Performance 9 inch on slicks. 408ci with LS3 heads and intake. Car also had some BMR/UMI tubular parts as well. Fast car but slow.....
Last edited by dreadpirateroberts; Oct 26, 2018 at 09:12 AM.
Way more bad combos than good combos out there. Don't build off the bad ones....build off the good ones. But combos like that is why i recommend guys run 11s with bolt ons before camming/building these cars. The oe engines are very powerful if you get everything else around them working.
for the most part, unless you are a master at designing these engines, the best most of us can do is understand the principles behind this stuff, and look at people's combos to see what works or not.
and it is relatively amazing what a full-bolt-on cathedral head LS can put out. 6.0's putting out close to 400whp with nothing but bolt-on's is fairly good, just have to find a way to put that to the ground as best possible.
Way more bad combos than good combos out there. Don't build off the bad ones....build off the good ones. But combos like that is why i recommend guys run 11s with bolt ons before camming/building these cars. The oe engines are very powerful if you get everything else around them working.
But as far as that combo goes i would start by chucking that ls3 intake and 90mm tb for a 408.
Just because someone bought a bunch of suspension parts don't mean it's better either.....sometimes it just means they bought a bunch of suspension parts.
But as far as that combo goes i would start by chucking that ls3 intake and 90mm tb for a 408.
Just because someone bought a bunch of suspension parts don't mean it's better either.....sometimes it just means they bought a bunch of suspension parts.
Originally Posted by Chris25
I still cant believe with the information available either on this forum or just in general that people keep putting terrible combos together. I think unfortunately its more about the sound a car makes with a giant cam than how it performs. Suspension in my eyes is the same as building a motor one part needs to compliment the other otherwise it will perform like junk.
Fast forward...
Wtf wrong wif my motor no whorespowers!
@Tusky - I would need to see how the car was driven, but my gut is 408 with ls3 heads but no rpm or choked off with a smaller intake or crappy Y pipe. I generally see a lot of 408 in particular underperform. Regardless if its ls3 or cathedral headed. Idk why. One of the reasons I went 428.
Not too hard to imagine. I think I will get x Uber performance part from magazine A and Y Uber Uber performance part from Magazine B. One is good so both are better! So excite! Cannot wait!
Fast forward...
Wtf wrong wif my motor no whorespowers!
@Tusky - I would need to see how the car was driven, but my gut is 408 with ls3 heads but no rpm or choked off with a smaller intake or crappy Y pipe. I generally see a lot of 408 in particular underperform. Regardless if its ls3 or cathedral headed. Idk why. One of the reasons I went 428.
Fast forward...
Wtf wrong wif my motor no whorespowers!
@Tusky - I would need to see how the car was driven, but my gut is 408 with ls3 heads but no rpm or choked off with a smaller intake or crappy Y pipe. I generally see a lot of 408 in particular underperform. Regardless if its ls3 or cathedral headed. Idk why. One of the reasons I went 428.
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Originally Posted by Tuskyz28
@darth .... just how much do you think a Y pipe setup can hold a car back compared to a x pipe true dual setup at the track ?
Edit -- and it moved peak hp up in rpm, so it carried further.
Thread Starter
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From: over dere
no you’re not. Unless you have to go to wot just to get around.
Thread Starter
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From: over dere
To the masters of "what everyone wants with their cars". Actually being "what I like for my cars & everyone else should too". So what is the tq difference between the two heads at say 15-20% throttle at 1500-2500 rpm? Or do you guys just drive on the street at WOT 100% of the time? The masters will shine with this answer..
except when you go to wot to race. Then you’re at 100% throttle. So do you downshift to get to 5000 rpm, or do you upshift so you can be at 2500-3000 rpm because you have tq there
Originally Posted by big hammer
no you’re actually right. You only spend most of your time on the street at say 3500 rpm or less and 15-20% throttle. And max power comes at WOT. So unless you’re having to go to WOT just to get around, you actually aren’t using you’re maximum tq jist to commute. So whether it makes 350 or 400 ft\lbs at 3000 rpm at 100 % throttle is irrelevant
except when you go to wot to race. Then you’re at 100% throttle. So do you downshift to get to 5000 rpm, or do you upshift so you can be at 2500-3000 rpm because you have tq there
except when you go to wot to race. Then you’re at 100% throttle. So do you downshift to get to 5000 rpm, or do you upshift so you can be at 2500-3000 rpm because you have tq there
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From: Lawrenceburg Ky
I've got a 421 with lightly ported LS3 heads that goes 6.56 (1/8 mile), 10.42(1/4 mile) on a 1.36 sixty and 128 mph..
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.5 degrees of more timing?
Cmon. and no cam specs plus fairly low cr for a 427 even.
Since tfs offers both a rect port and cathedral why didnt they test them?
The actual list of what is the same between the two is shortblock and both use a holley hi ram.
The rest of it falls into the gray area between the pages so to speak.
"The cams are close" - way too broad and vague
Timing curves very close? Ive seen quite a few cathedrals take 28 to 30* and quite a few rect ports take 24 to 26*....so cmon.
And only showing a graph from 4800 and up...thats pretty ridiculous.
None of that passes the sniff test, especially since ive seen odd torque dips on most ls3 headed setups vs cathedral in the lower mid-range rpms. Those that either dyno alot or compare alot know what i am talking about. Cathedrals normally dont do that unless the engine dyno operator loads the test cell differently.
That is really why i prefer chassis dyno as you can see a cleaner graph in alot of aspects as well and see how it will really act in a vehicle. You can then compare between the two also if you want which is what dynos are really for.
Too many secrets to borrow from Sneakers....but too many questions also.
At least 50% relevant...but not more than 75% imo
Cmon. and no cam specs plus fairly low cr for a 427 even.
Since tfs offers both a rect port and cathedral why didnt they test them?
The actual list of what is the same between the two is shortblock and both use a holley hi ram.
The rest of it falls into the gray area between the pages so to speak.
"The cams are close" - way too broad and vague
Timing curves very close? Ive seen quite a few cathedrals take 28 to 30* and quite a few rect ports take 24 to 26*....so cmon.
And only showing a graph from 4800 and up...thats pretty ridiculous.
None of that passes the sniff test, especially since ive seen odd torque dips on most ls3 headed setups vs cathedral in the lower mid-range rpms. Those that either dyno alot or compare alot know what i am talking about. Cathedrals normally dont do that unless the engine dyno operator loads the test cell differently.
That is really why i prefer chassis dyno as you can see a cleaner graph in alot of aspects as well and see how it will really act in a vehicle. You can then compare between the two also if you want which is what dynos are really for.
Too many secrets to borrow from Sneakers....but too many questions also.
At least 50% relevant...but not more than 75% imo
Thread Starter
10 Second Club
Joined: May 2009
Posts: 3,427
Likes: 227
From: over dere
.5 degrees of more timing?
Cmon. and no cam specs plus fairly low cr for a 427 even.
Since tfs offers both a rect port and cathedral why didnt they test them?
The actual list of what is the same between the two is shortblock and both use a holley hi ram.
The rest of it falls into the gray area between the pages so to speak.
"The cams are close" - way too broad and vague
Timing curves very close? Ive seen quite a few cathedrals take 28 to 30* and quite a few rect ports take 24 to 26*....so cmon.
And only showing a graph from 4800 and up...thats pretty ridiculous.
None of that passes the sniff test, especially since ive seen odd torque dips on most ls3 headed setups vs cathedral in the lower mid-range rpms. Those that either dyno alot or compare alot know what i am talking about. Cathedrals normally dont do that unless the engine dyno operator loads the test cell differently.
That is really why i prefer chassis dyno as you can see a cleaner graph in alot of aspects as well and see how it will really act in a vehicle. You can then compare between the two also if you want which is what dynos are really for.
Too many secrets to borrow from Sneakers....but too many questions also.
At least 50% relevant...but not more than 75% imo
Cmon. and no cam specs plus fairly low cr for a 427 even.
Since tfs offers both a rect port and cathedral why didnt they test them?
The actual list of what is the same between the two is shortblock and both use a holley hi ram.
The rest of it falls into the gray area between the pages so to speak.
"The cams are close" - way too broad and vague
Timing curves very close? Ive seen quite a few cathedrals take 28 to 30* and quite a few rect ports take 24 to 26*....so cmon.
And only showing a graph from 4800 and up...thats pretty ridiculous.
None of that passes the sniff test, especially since ive seen odd torque dips on most ls3 headed setups vs cathedral in the lower mid-range rpms. Those that either dyno alot or compare alot know what i am talking about. Cathedrals normally dont do that unless the engine dyno operator loads the test cell differently.
That is really why i prefer chassis dyno as you can see a cleaner graph in alot of aspects as well and see how it will really act in a vehicle. You can then compare between the two also if you want which is what dynos are really for.
Too many secrets to borrow from Sneakers....but too many questions also.
At least 50% relevant...but not more than 75% imo