Which GM cam to perfect the L31?

[89GMCJOHN]

I have had a stock Ramjet apart. It came with the same 1.6 self align designed rockers that came in the 1996 LT4 Vette and the LT4 Hotcam package came with that was goin into it.

Tell Chevrolet , Jegs etc they got their parts list wrong .....

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[L31MaxExpress]

Tell Chevrolet , Jegs etc they got their parts list wrong .....

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Maybe something has changed on the newer ones but for 10 years I have seen it listed as 1.6 and the rockers in that engine had a small 1.6 stamping on them too.

https://www.jegs.com/i/Chevrolet-Pe...MI5u7f1P2Z3AIVGbjACh0sVQKEEAYYASABEgK7fvD_BwE

Also even if they are only 1.5s now, still better than the POS stamped 1.42s that come on every other small block.

 

[89GMCJOHN]

Cool ,,,but on top of all the used parts in that build for $500 - they bought their distributor at Oreillys per the article ...as you know those distributors come with ridiculously STIFF springs which we all yank out first thing to get a better curve . Like I said they never would have equaled the EFI power or torque numbers but could have gotten closer... L31 I am not here to argue but simply stating that the 395 is a tiny cam BUT lays down pretty good numbers in a Gen1 for what it is ....that has been proven over and over again in numerous articles everywhere or from peoples personal testimonies ..... even in a non optimized , used engine scenario the 320 "400" it put down is nothing to sneeze at from such a tiny cam ...... you just come across as abruptly discounting others opinions on their combos or scoffing at their reported dyno numbers like you did to that guy on the LT1 B cam vs F cam version . PEACE ... I look forward to reading your posts when I run across them ....

 

[L31MaxExpress]

Just for the record we are BOTH right on the Ramjet. The older part number had 1.6s. The newer number has 1.5s. I pulled up the part list that I saved 3 years ago. The newest Ramjet is only rated 345 hp and 396 tq compared to 351 hp and 403 tq of the older. The new version has an entirely different part number. The rockers in the old version are listed as discontinued. In the old GM spec sheet valve lift is specified as .460/.481.

 

[89GMCJOHN]

So one thing still puzzles me.

I still do not understand your comment with my comment being wrong with the LSA so please express yourself or is LSA a concept you have a poor grasp of?

Yes tighter LSA builds more cylinder pressure and brings the RPM for peak torque down. However it also increases overlap. On any vehicle with an actual exhaust system that is not designed like a race car exhaust the added overlap will dilute the intake charge at lower rpm like off-idle and part-throttle which will hurt low end torque despite the increased cylinder pressure.

I also had 2 different cam grinds in my 2006 Hemi Ram when I owned it. With the stock torque converter, 4.56 gears, 32" tall P305/50R20s, BBK shorty headers, stock cats, magnaflow Y and a magnaflow muffler at the time I ran back to back testing in very similar weather conditions. First cam was a dual pattern grind. 214/222 @ 0.50 on a 112 LSA and 3° advanced. The second cam was a 214/214 @ .050 single pattern cam on a wider 114 LSA with 4° advance and it had a 60' time that was nearly 0.2 of a second quicker. It ended up being a full 1/2 second quicker in the 1/8 mile. The 1st cam was a modern Crower grind. 2nd cam was a Comp with XFi lobes. 1st cam had a bit of idle lope. 2nd cam had a very stock like idle and nearly 3 in/hg more vacuum. The single pattern cam also got as much as 4 mpg highway better when it was in MDS (4cylinder)mode. 1st cam ran a 9.3 @ 76 on a dead hook 2.2x 60'. 2nd cam ran an 8.8 @ 77 on a 1.98s 60'.

Great article on LSA 3 cams with just different LSA https://www.hotrod.com/articles/camshaft-shootout-lobe-separation-angle-tested-explained/

LSA Horsepower Torque Cranking Compression Idle Vacuum

101 484.0 at 6,100 rpm 493.9 at 4,400 rpm 185 psi 9.8

107 488.7 at 6,200 rpm 487.1 at 4,600 rpm 180 psi 12.2

113 490.5 at 6,200 rpm 472.4 at 4,700 rpm 175 psi 14.7

LSA AT A GLANCE
Narrower LSA:

• Moves torque to lower rpm
• Increases maximum torque
• Narrow powerband
• Increase chance of engine knock
• Increase cranking compression
• Idle vacuum and quality is reduced
• Valve overlap increases
• Decreases piston-to-valve clearance

Wider LSA:

• Raise torque to higher rpm
• Reduces maximum torque
• Broadens powerband
• Decrease chance of engine knock
• Decrease cranking compression
• Idle vacuum and quality is improved
• Valve overlap decreases
• Increases piston-to-valve clearance

 

[slowburb]

Great article on LSA 3 cams with just different LSA https://www.hotrod.com/articles/camshaft-shootout-lobe-separation-angle-tested-explained/

LSA Horsepower Torque Cranking Compression Idle Vacuum

101 484.0 at 6,100 rpm 493.9 at 4,400 rpm 185 psi 9.8

107 488.7 at 6,200 rpm 487.1 at 4,600 rpm 180 psi 12.2

113 490.5 at 6,200 rpm 472.4 at 4,700 rpm 175 psi 14.7

LSA AT A GLANCE
Narrower LSA:

• Moves torque to lower rpm
• Increases maximum torque
• Narrow powerband
• Increase chance of engine knock
• Increase cranking compression
• Idle vacuum and quality is reduced
• Valve overlap increases
• Decreases piston-to-valve clearance

Wider LSA:

• Raise torque to higher rpm
• Reduces maximum torque
• Broadens powerband
• Decrease chance of engine knock
• Decrease cranking compression
• Idle vacuum and quality is improved
• Valve overlap decreases
• Increases piston-to-valve clearance

How did they manipulate LSA? Move intake lobe? Move exhaust lobe? Move both lobes?

 

[89GMCJOHN]

How did they manipulate LSA? Move intake lobe? Move exhaust lobe? Move both lobes?

No clue....

 

[slowburb]

No clue....

Those numbers are important.

 

[arrg]

How did they manipulate LSA? Move intake lobe? Move exhaust lobe? Move both lobes?

They moved the intake only on the 107 and moved both on the 113. The IVC moved 6 degrees when the LSA went from 101 to 107 but only moved 2 degrees when the LSA went from 107 to 113.

 

[sharpe.trey]

So does the Elgin E1136 cam just drop in minus a tune?