Good info

 

Wow, I am going to have to read this twice to get a good grip on this info. Thanks Martin we needed this.

 

Where's the "Like" button?

Great thread.

 

Great thread, glad to see LSx shops educating the enthusiasts, the more we learn and know, the more the sport grows.

 

I actually learned something I hadn't ever considered before.

 

I'm glad you guys are enjoying this thread and have actually been able to take something away from it. That's what it's all about to me. Good stuff for sure!

I will be posting some more topics about pressure waves in the exhaust regarding stepped header designs versus conventional single step designs. Another topic that will be discussed as well is how a stamped collector changes pressure waves and dynamics versus a fabricated merged collector.

Stay tuned over the holidays for more info!

 

Is it the holidays yet....???
Fill our needles Martin.......

 

I think I ate so much food yesterday that I forgot!

 

A lot to wrap my head around but great write up..

 

Great post! This is why I will be using Tick Performance for my build. I like knowing WHY I am choosing a certain camshaft, heads, clutch, whatever......and not just buying whatever is popular at the moment. Thank you!

 

I'd love to hear how Tri-Y headers change things as well...

 

Be careful when using Tri-Y headers as their design (paired cylinders) needs to match the firing order used as well for them to work properly.

 

Hmm. I'll have to check mine out and see which are paired. I haven't been underneath the car in a while. I'd like to think Pfadt knew what they were doing, but then again, they're out of business, so... All I've heard is they love overlap; and that's fine with me.

 

Could you explain this to me? Not sure what you mean when you say their design needs to match the firing order.

 

Sorry for getting off topic, but saw Tri-Y's mentioned and thought I should say that.

Tri-Y headers pair specific cylinders to scavenge together based on an engine's firing order and exhaust pulses. Tri-Y headers designed for a traditional small block chevy/big block chevy/W-motor, etc. with the standard 18436572 Firing order will not work correctly on an engine with a different firing order such as the popular 4/7 swap camshafts often used today. Probably of zero concern for an LS1 family engine since I'm not aware of any firing order swap camshafts used for those, but since this thread may be read by people on this site building an LT1 (92-97 not Gen V) then it may be good info for them to know.

I myself was reading this article after recently purchasing a new (but second hand) camshaft for my current build simply because it was about $175 cheaper than a new one. This camshaft has slightly higher duration than I was planning on, but a wider LSA so I was intrigued by this thread.

For what it's worth, the planned camshaft was 242*I / 248* E @ .050" on a 110* LSA. The bought camshaft is 248*/258* @ .050" on a 113* LSA.
Displacement = 478"

I do not expect the bought camshaft to have identical rpm range, peaks, and characteristics of the one I'd planned.....but after reading this I believe that for my build and budget it will work just fine.

 

Are there any companies that make TRI-Y headers for the LS1? Sounds like it would be beneficial if they are made specific to the firing order.

 

I thought doug throley did for a while, not sure if they/he still do.

 

I know bassani exhaust made tri y headers for c5 corvette

 

My question is this: what determines when the intake/exhaust valve opens on a motor?

IE: on the LS1 motor, at what degree do you want the valves to open? What determines this? I talked with roger vinci some years ago about this but memory fades me.

I know there's a too early and late degree range.

 

Wrhjo