To bore or not to bore?

[ross.cottrill]

im getting ready to do a rebuild and i was wondering if anyone has gone up to a 90mm piston?will this be much better than say a 87mm?will it really help spool and torque that much by being a 2.2 liter?any input would be greatly appreciated!!...ross

[steve shadows]

Honestly it's a loaded question.

But without the proper tuning and the reasoning behind the change in displacement it's over rated.

The cost is usually not worth the gains unless the car is truley built around a purpose etc.

The benefit of this way of enlarging displacement is that there is no increase in piston speed.

[ross.cottrill]

hey steve thanx for chiming in.the purpose would be to get better spool out of my t/s 3071 for my daily driver.the cost is alot higher of course to sleeve it.just seeing if there would be any signifigant difference..thanx

[landins13]

im running a 2.2 but its on the brian crower stroker kit, not from boring out the cylinder walls, on a daily it wouldnt be worth it, if its a track car that you intend to tune fairly frequently. initially tuning my car was a pain, but once you get the kinks worked out, having the larger displacement def helps spool the turbo, also another option to consider, which is something i did on my dd when i spun a rod bearing, get a crank that has been knife edged and lightened, by reducing the weight of the rotating assembly you save horsepower, and it requires less effort by the engine to spin itself.

the main thing i noticed with that is it takes less time for my motor to gain rpm, like the amount of time it takes to go from 2k-3k-4k, and so

[aNskY]

what is "safe" bore on an sr before you need sleeves?

and what will 86.5mm bore yeild in terms of displacement?

[ross.cottrill]

im pretty sur you can go to a 87mm bore on stock sleeves.

[Teambadrun]

I had 87mm till i broke a rod haha so now im going 90mm i hope it's better!!
I still have the pistons out of it ( luckily not damage) Tomei 87mm 15,000k's old they are for sale $400USD :D

I felt the differnce from 86 to 87.. so i cant wait to see 90mm