I have the Compucar, and dynoed 379 NA, and 480 with a 100 shot nitrous jet & 150 fuel jet (converter not locked). The 100 shot fuel jet was too lean. Now I'm a little richer than I need, but I'd rather be a little rich.

This is the stock bottom end. I could squeeze a few more hp, by jetting up the nitrous 1 or 2 notches.

What is my limit here? So far, with the 480 hp, I have no detnation.

 

I say take it up to a 150shot. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

If you figure a 20% loss, that comes out to 630 at the motor. I guess my question is, how much is the limit on the stock bottom end? 600? 700?

 

The bottom end can take a lot as long as its getting plenty of fuel and doesn't lean out...

Build a fuel system like I am going to do, and not have to worry about going lean... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

The general rule of thumb used by most pro engine builders is: If you have a 400 HP N/A Motor, and a 100 HP shot... build the motor as if it would take ATLEAST 500 HP N/A.

As a saftey measure, I would see if they make Splayn caps for the LS1. That would not be difficult to do labor wise. Splayn caps add alot of bottom end strenth, but I'm sure your current setup would take a 150 shot fine.

Another concerns is the aluminum block. Aluminum blocks generally will not take as much as cast. Reguardless, I am sure it will still take quite a bit. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

 

For my knowledge, can someone explain what is the difference with the converter not locked?
Thanks,

 

I would take an occasional risk of 650. That's "only" 74 more than what I am pushing now.

480 x 1.20= 576

Factoring in a 20% loss with the A4/ Vig 3200.

That seems like a pretty big jump,and equals out to about a 175 shot <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

 

Matt,
You are very correct. I was trying to go with concerns after the mains, not before.
But you have a very good point. I would worry about the rods and pistons,etc long before the bottom end and the block. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

<small>[ June 18, 2002, 09:58 PM: Message edited by: Andy West ]</small>

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Andy West:
<strong>The general rule of thumb used by most pro engine builders is: If you have a 400 HP N/A Motor, and a 100 HP shot... build the motor as if it would take ATLEAST 500 HP N/A.

As a saftey measure, I would see if they make Splayn caps for the LS1. That would not be difficult to do labor wise. Splayn caps add alot of bottom end strenth, but I'm sure your current setup would take a 150 shot fine.

Another concerns is the aluminum block. Aluminum blocks generally will not take as much as cast. Reguardless, I am sure it will still take quite a bit. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I don't think you'll see the block being an issue here. I'd sweat the rod bolts long before I'd sweat that block. But I'd trust the stock bottom end to 550+rwhp reliably, and to 650 if you want to risk it. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> I may risk it some day.... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

- Matt

 

Splayed mains? You know those thigns have 6 bolt mains already? Id be worried about the fact the GM puts rod bolts that are too short in them from the factory <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

WHAT THA HELL DOES SPLAYED MEAN? I'VE HEARD THAT A MILLION TIMES BUT I CAN NEVER GET A STRAIGHT ANSWER FROM ANYBODY? IS IT LIKE A STUD GIRDLE OR SOMETHING?

 

Splayed means the outer main bolts are at an angle which makes it more rigid and displace load more evenly. regular 4 bolts are set up like this:
i11i. A splayed cap is like this /11\ with the outer bolts being a little shorter than shown. The outer bolts are angled. Our ls1's are like a hemi mopar or side oiler Ford: -1111-. The problem with our ls1's are the rod bolts and pistons. Both are much weaker than the block and crank.I would say anything more than 525 rwhp will have limited life at best. Detonate hard at 480rwhp and it wont last long.

 

I RAN A 150 SHOT IN MY STOCK 98Z28 SINCE 98 WITH NO PROBLEMS, I ALSO HAD A 350 SHOT ON A 65 NOVA, JUST ADD A LITTLE HIGHER OCTAIN MAYBE 100 UNLEADED TO BE SAFE I NEVER HAD PROBLEMS, BUT I ALWAYS USED GOOD GAS