Whats the deal with LS motors? Someone told me it means long stroke...but i see it with integra's, civics, and others. They'll say its an LS motor as if thats what the motors called, rather than a normal engine code b16, b18, etc..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr. Travis &raquo;</TD></TR><TR><TD CLASS="quote">Whats the deal with LS motors? Someone told me it means long stroke...but i see it with integra's, civics, and others. They'll say its an LS motor as if thats what the motors called, rather than a normal engine code b16, b18, etc..</TD></TR></TABLE>

They are commonly reffered to as the "LS" motor because that is the trim level of Integra they were mostly offered in. Their true engine codes are B18A (9?-93 Integra LS / GS models) and B18B (94+ LS, GS, RS, and SE models).

 

They are called LS engines because they are most commonly found in the Integra LS. They do have a longer stroke meaning more displacement, however this comes at a price: due to the longer stroke, the rod ratio suffers, which keeps these engines from being able to rev like the VTEC engines can.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">due to the longer stroke, the rod ratio suffers, which keeps these engines from being able to rev like the VTEC engines can.</TD></TR></TABLE>

If i hear this again im going to **** my self.

b18c = 1.58 RS
b18b = 1.54 RS

b16a = ~ 1.7

Next thing you know it im going to be telling you that you dont need to be revving your b18c up to 8k because it has a bad RS compared to a b16.

There are other things about the ls motors that prevent it from revving as high as the vtec motors. The rod stroke ratio is not the soul reason you cant rev a stock ls motor as high as a b18c.

-sander

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sander &raquo;</TD></TR><TR><TD CLASS="quote">There are other things about the ls motors that prevent it from revving as high as the vtec motors. The rod stroke ratio is not the soul reason you cant rev a stock ls motor as high as a b18c.</TD></TR></TABLE>

The rod/stroke ratio, the comparitive lack of balance with the stock crank, the lack of the oil squirters for proper cooling, the list goes on. When dealing with noob's I like to take things one step at a time. When he asks about the rod/stroke ratio, we then tell him about the remaining problems. You know, hit them with a small stick before you drop a tree on them.

 

I am probably one of the few that doesn't believe its the wear of the rod/stroke ratio that makes the difference in high reving. A properly built block is going to be able to take the stress of high reving, forged pistons deal with heat better, you can machine the rods to accept the larger B18C bearings, etc

The difference in piston dwell time is really what I see as a limiting factor of B18B/B20 Block being able to rev as high as a B16/B18CX.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by StyleTEG &raquo;</TD></TR><TR><TD CLASS="quote">I am probably one of the few that doesn't believe its the wear of the rod/stroke ratio that makes the difference in high reving. </TD></TR></TABLE>

You and me both pal.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">

The rod/stroke ratio, the comparitive lack of balance with the stock crank, the lack of the oil squirters for proper cooling, the list goes on. When dealing with noob's I like to take things one step at a time. When he asks about the rod/stroke ratio, we then tell him about the remaining problems. You know, hit them with a small stick before you drop a tree on them.</TD></TR></TABLE>

Understood, just know thats not a valid reason why LS motors cant rev as high. But i do understand your point about teaching.

-sander

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">

The rod/stroke ratio, the comparitive lack of balance with the stock crank, the lack of the oil squirters for proper cooling, the list goes on. When dealing with noob's I like to take things one step at a time. When he asks about the rod/stroke ratio, we then tell him about the remaining problems. You know, hit them with a small stick before you drop a tree on them.</TD></TR></TABLE>


IF im not mistaken the ls rods have a type of oil passage build right into em. That squirts oil to the wrist pin area.

 

ROD/STROKE RATIO AND ROD LENGTH:

B16A: 1.74/ 134MM
B17A1: 1.62/131.87MM
B18A1: 1.54/ 137MM
B18B: 1.54/137MM
B18C1: 1.58/137.9MM
B18C5: 1.58/137.9MM
B20A3/53RD GEN LUDE) 1.50/142.75MM
B21A1: 1.492/141.7MM
B20B: 1.539/137MM


And the ideal R/S for an engine is ~1.75, yay B16a. You forgot that even the Honda schools in Japan hate the B18 engines so much they give them to the students to break and learn.