anyone want to place bets on how long my sleeves last?
the assumptions being that there are some long duration cams and a shitload of overlap, the ecu is tuned to perfection and i run it on good fuel at all times.

i'm going ahead with it regardless... i have alot of faith in my tuner and engine builder, but we seem to be heading into uncharted territory at the moment

it feels strange to be kicking conventional wisdom in the teeth. i wonder if it will all end in tears.

 

I'm running 12.0:1 on stock sleeves at 85 mm. No problem for 10k miles. I think you a pussing it with 13.0:1. Jeff from IB once told me 12.8:1 would be max on stock sleeves. Good luck with the engine....

 

im somewhere between 12.5 and 13.0 on 84.5mm stock sleeves . like you said good tuning and proper crankcase venting is key. im running BC4's the add duration should help your cause. my motor is almost 2 years old and over 15k miles. good luck.

 

why not run less compression and less overlap

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Used2beAb16 &raquo;</TD></TR><TR><TD CLASS="quote">why not run less compression and less overlap</TD></TR></TABLE>

because that = less power.

 

Ive only run 12:1 on stock b20 sleeves.I had a friend at another shop run 15:1 on a stock sleeved b20 with crane 3 cams and a 95mm crank.It lasted through nopi houston and nopi ennis until a rod broke through the block.

 

why would less overlap = less power??? Why not pick an good amount of compression that would allow u to run less overlap without detonation.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by omniman &raquo;</TD></TR><TR><TD CLASS="quote">the sleeve cracking or breaking is not cause by the compression. its caused be the detonation from the lack of octane. and rpm and vibration help some too.

</TD></TR></TABLE>

But detonation can be caused from too high of a compression ratio for the octane of fuel being combusted. So to combat this he is electing to run big *** cams that will indeed lower his dynamic compression by inducing alot of overlap. It seems that many people do this. But how can the compression be making anypower when its being bled off?? It would seem that if u could run a little lower compression, and trap more of it in, it could make the same power.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Used2beAb16 &raquo;</TD></TR><TR><TD CLASS="quote">

But detonation can be caused from too high of a compression ratio for the octane of fuel being combusted. So to combat this he is electing to run big *** cams that will indeed lower his dynamic compression by inducing alot of overlap. It seems that many people do this. But how can the compression be making anypower when its being bled off?? It would seem that if u could run a little lower compression, and trap more of it in, it could make the same power. </TD></TR></TABLE>

he is not inducing anything. the higher compression just allows him to run large cams designed w/ a lot of overlap and make the most of them.

 

thanks for the support!

and here i was expecting to get flamed

 

There ya go Slim this combo is not something that I have not given alot of time and energy to and researched for many months but first we will make the B18C1 go the way it should.
Regards Dyno Dave

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by na200whp &raquo;</TD></TR><TR><TD CLASS="quote">

because that = less power.</TD></TR></TABLE>

not always.........seen less compression and overlap destroy alot of motors here with high *** cr etc, even tuned right....its all in the right combination of parts

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dyno Dave &raquo;</TD></TR><TR><TD CLASS="quote">There ya go Slim this combo is not something that I have not given alot of time and energy to and researched for many months but first we will make the B18C1 go the way it should.
Regards Dyno Dave </TD></TR></TABLE>

thats where the party's at me old china

*free plug* Dyno Dave - best tuner in oz


Modified by slimbo at 9:37 AM 12/8/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by omniman &raquo;</TD></TR><TR><TD CLASS="quote">the sleeve cracking or breaking is not cause by the compression. its caused be the detonation from the lack of octane. and rpm and vibration help some too.

</TD></TR></TABLE>

im gonna agree 100% on this. i have a cracked #1 cylinder sleeve on my 84.5mm B20 with only 11:1CR......it went untuned for to long. i dont think its really a compression thing just a tuning/timing thing.

 

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

not always.........seen less compression and overlap destroy alot of motors here with high *** cr etc, even tuned right....its all in the right combination of parts </TD></TR></TABLE>

Exactly, i mean for streetabilitys sake. (limits of octane) you could probably make as much power with a point less compression, and a little less overalp. Now if u can run 110 octane and send the compression through the roof, then by all means the overlap matter cuz theres so much static compression to begin with.