bore and compression

john_trickle · Post by **john_trickle** » Tue Mar 27, 2007 9:29 pm

Hey guys quick question im getting new forgerd pistons and rings,and forged connecting rods i need to know what is the best bore and compression to do for the 1.5l lanos with turbo let me know thanks.

MMamdouh · Post by **MMamdouh** » Tue Mar 27, 2007 10:18 pm

didn't get your question here... your current bore and stroak is what makes your engine a 1.5, changing that will chanbe your displacment and/or compression.

MMamdouh

jorge · Post by **jorge** » Tue Mar 27, 2007 10:38 pm

And its better from 76.5 to 79.0...

Post by **PrecisionBoost** » Tue Mar 27, 2007 10:56 pm

In my opinion 8.5:1 to 8.8:1 is about right for an average build up.

If you were going for very high levels of boost I would say 8.0:1 to 8.5:1 would be better.

If you were looking for high boost levels I would also suggest staying at your current bore to maximize the thickness of the cylinder walls.

I also assume your planning to have the engine rebuilt and bored out.

Assuming that the engine has not been rebuilt before I would suggest simply 0.050" over pistons.... that should allow for enough clearance that the machine shop can bore it out nicely.

Displacement is very important in a naturally aspirated engine.... but that is simply not the case in a forced induction engine.

Think about it this way....

If you have a 1.6L and your running about 15psi of boost you could theoretically stuff about 2.9L of air/fuel into your cylinder (assuming a NA Volumetric eff of roughly 90% )

Let's just pretend for a second that the 1.5L has the identical Volumetric efficency.

That means that you would need to push 17psi to make the same power levels.

Realisticly the difference between 15psi and 17psi is negligible from an engine building point of view.

In fact.... the 1.5L with it's thicker cylinder walls will be stiffer and capable of taking more boost.

wolfhound · Post by **wolfhound** » Wed Mar 28, 2007 8:56 am

John

Where did you get the Rods from ? What did they cost you ?

I am expecting my Forged Pistons from Wiseco to be posted by the end of the month but was gonna use the std rods (1600 16v)

it might be a plan 4 me to get hold of a set of the performance rods as well.

Séan

john_trickle · Post by **john_trickle** » Wed Mar 28, 2007 9:01 pm

wolfhound wrote:John

Where did you get the Rods from ? What did they cost you ?

I am expecting my Forged Pistons from Wiseco to be posted by the end of the month but was gonna use the std rods (1600 16v)

it might be a plan 4 me to get hold of a set of the performance rods as well.

Séan

I got it from http://www.importperformanceparts.net/

good products and good price range $715 for the rods im egar to get them.

john_trickle · Post by **john_trickle** » Wed Mar 28, 2007 9:05 pm

PrecisionBoost wrote:In my opinion 8.5:1 to 8.8:1 is about right for an average build up.

If you were going for very high levels of boost I would say 8.0:1 to 8.5:1 would be better.

If you were looking for high boost levels I would also suggest staying at your current bore to maximize the thickness of the cylinder walls.

I also assume your planning to have the engine rebuilt and bored out.

Assuming that the engine has not been rebuilt before I would suggest simply 0.050" over pistons.... that should allow for enough clearance that the machine shop can bore it out nicely.

Displacement is very important in a naturally aspirated engine.... but that is simply not the case in a forced induction engine.

Think about it this way....

If you have a 1.6L and your running about 15psi of boost you could theoretically stuff about 2.9L of air/fuel into your cylinder (assuming a NA Volumetric eff of roughly 90% )

Let's just pretend for a second that the 1.5L has the identical Volumetric efficency.

That means that you would need to push 17psi to make the same power levels.

Realisticly the difference between 15psi and 17psi is negligible from an engine building point of view.

In fact.... the 1.5L with it's thicker cylinder walls will be stiffer and capable of taking more boost.

Thank for that PrecisionBoost that was extremely helpful now i can place my order at IPP

john_trickle · Post by **john_trickle** » Wed Mar 28, 2007 9:31 pm

john_trickle wrote:
PrecisionBoost wrote:In my opinion 8.5:1 to 8.8:1 is about right for an average build up.

If you were going for very high levels of boost I would say 8.0:1 to 8.5:1 would be better.

If you were looking for high boost levels I would also suggest staying at your current bore to maximize the thickness of the cylinder walls.

I also assume your planning to have the engine rebuilt and bored out.

Assuming that the engine has not been rebuilt before I would suggest simply 0.050" over pistons.... that should allow for enough clearance that the machine shop can bore it out nicely.

Displacement is very important in a naturally aspirated engine.... but that is simply not the case in a forced induction engine.

Think about it this way....

If you have a 1.6L and your running about 15psi of boost you could theoretically stuff about 2.9L of air/fuel into your cylinder (assuming a NA Volumetric eff of roughly 90% )

Let's just pretend for a second that the 1.5L has the identical Volumetric efficency.

That means that you would need to push 17psi to make the same power levels.

Realisticly the difference between 15psi and 17psi is negligible from an engine building point of view.

In fact.... the 1.5L with it's thicker cylinder walls will be stiffer and capable of taking more boost.
Thank for that PrecisionBoost that was extremely helpful now i can place my order at IPP

also is there a better head gasket kit to get or are they all the same ill also change the timming belt and tenioners what else should i change while im at it, im doing a port and polish on the throttle bodie and head and also getting custom headers let me know what other bits i need while im doing the rebuild.
john

wolfhound · Post by **wolfhound** » Thu Mar 29, 2007 5:56 am

Careful John

Thats where i got my Wiseco pistons from. They were supposed to be the 8.8-1 ones.

WRONG. just check the pic below and see just how shallow the dish was compared to the std Woo piston. I think Ubuyau bought Ross pistons, his photos show just how deep the dish should be.

I ended up posting them back to Wiseco themselves...... very very helpful guy called Dwayne, (coz Phil from IPP was just way to slack).

DSnyder@wiseco.com

Wiseco are now making the correct ones for me.

Sooooooo just make sure you
a) Don't deal with Phil @ IPP

b) Make sure they are the correct low compression pistons

Wiseco NOW have one of my original pistons as a sample so you should be able to get eh right ones.

Séan

john_trickle · Post by **john_trickle** » Thu Mar 29, 2007 6:09 am

wolfhound wrote:Careful John

Thats where i got my Wiseco pistons from. They were supposed to be the 8.8-1 ones.

WRONG. just check the pic below and see just how shallow the dish was compared to the std Woo piston. I think Ubuyau bought Ross pistons, his photos show just how deep the dish should be.

I ended up posting them back to Wiseco themselves...... very very helpful guy called Dwayne, (coz Phil from IPP was just way to slack).

DSnyder@wiseco.com

Wiseco are now making the correct ones for me.

Sooooooo just make sure you
a) Don't deal with Phil @ IPP
b) Make sure they are the correct low compression pistons

Wiseco NOW have one of my original pistons as a sample so you should be able to get eh right ones.

Séan

Thanks for the thumbs up man i appreciate it lucky i havent ordered yet.