to all you guys in street daily driven cars...what size bore do you consider to be too big for boost? any benefits at all when its anywhere past 84mm?

how about sleeving and starting at 81mm? Is it better to go big from the start or start small. Just want to be clear on things before my block goes out. I'll put my flame suit on now.

 

83mm for boost....84mm for n/a for DD

 

Im a big fan of the start small around 83mm. That way if something happens there is always more sleeve

 

thanks guys, i appreciate the comments

 

id like to hear more opinions on this ...

 

i feel the same way...83mm to start that way you have room to resleeve. And between 81mm and 84mm, its not that big of gain.

 

I started at 84mm. That gives me 1... maybe 2 rebuilds at the most.

 

do u regret starting with 84?

 

i started off at 84.5, if something happens ill just go bigger... and bigger. then eventually have the sleeves replaced and start over

 

I would say anything over 85mm for boost is too big.

 

i like 88mm

 

No regrets here. Id agree 85mm is the absolute max for a boosted B series. 84 is a good starting point with sleeves.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by flip1199 &raquo;</TD></TR><TR><TD CLASS="quote">i like 88mm </TD></TR></TABLE>
Quiet you! H23s dont count.

 

I don't get it.

The difference in displacement is so minimal it's not worth it to start at 84.5 or 85mm. It's not like your going to see gobs more tq by boring that much

 

I started at 84mm and have had NO problems on my daily driven boosted B-Series

 

I started at 84mm to. Im on my second sleeved block and i went 84mm again. I just like to say i have a 2.0 b-series.

 

I started at 81mm, looking back now I would have went 83mm.

Id like to see a comparison of 81mm vs. say 83 or 84mm and see what kind of differences it makes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by m R g S r &raquo;</TD></TR><TR><TD CLASS="quote">I don't get it.

The difference in displacement is so minimal it's not worth it to start at 84.5 or 85mm. It's not like your going to see gobs more tq by boring that much </TD></TR></TABLE>

It's like that with a lot of things. People worry so much about little things that don't matter too much. I mean all you would need to do is turn the boost up like 1 or 2 psi and you will have your extra hp/tq that the 1mm of displacement would make.

I would much rather start off at like 83mm or so... just incase.

 

What about a 76mm stock sleeve SOHC?

I see a lot of guys running 75.5mm setups, would it be possible/safe to run 76mm?

 

my hommie has a b16 with 86mm ge sleeves.

 

What about on stock sleeves is it worth it to go bigger, or will that just make the sleeves weaker?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by m R g S r &raquo;</TD></TR><TR><TD CLASS="quote">I don't get it.</TD></TR></TABLE>

Its about squeezing every last bit of power out of your setup. And its nearly free to go big bore. The sleeving is the same cost, the pistons are the same. Its proven to be reliable so why not?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">What about on stock sleeves is it worth it to go bigger, or will that just make the sleeves weaker?</TD></TR></TABLE>

Most overbore .5 so that they are assured the cylinders are perfectly round and have the correct clearances for the new pistons. Most of the stock sleeve dynos Jeff Evans was showing were on 81.5mm blocks with over 500whp. After 500whp you know that you are really pushing the limits and one thing goes wrong and the sleeves are done.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boostincoupe &raquo;</TD></TR><TR><TD CLASS="quote">What about a 76mm stock sleeve SOHC?

I see a lot of guys running 75.5mm setups, would it be possible/safe to run 76mm? </TD></TR></TABLE>

And this is for 300-350whp MAX.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by m R g S r &raquo;</TD></TR><TR><TD CLASS="quote">I don't get it.

The difference in displacement is so minimal it's not worth it to start at 84.5 or 85mm. It's not like your going to see gobs more tq by boring that much </TD></TR></TABLE>

I think a factor many people over look on this subject is not so much the sleeve thickness at 84.5-85mm but think about the meat you have left on that intake valve relief. IMO Id rather have more meat there than in the sleeves..It will take a lot longer to heat that spot up running a bigger bore, in turn giving you more reliabilty for a given tune. The sleeves are strong enough at 84.5, 85 mm to handle gobs of power.. there were/are many people in the top of SFWD that run that big and bigger.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boostincoupe &raquo;</TD></TR><TR><TD CLASS="quote">What about a 76mm stock sleeve SOHC?

I see a lot of guys running 75.5mm setups, would it be possible/safe to run 76mm? </TD></TR></TABLE>

If I remember correctly in the Benson sleeve thread Earl recommended 77mm for d-series and 83mm for b-series when starting out. That will leave you a few rebuilds. I guess it just depends on the person building the motor.