Stoked

[icyjaws]

Ok well i'm looking into really building an NA 200+ hp celica. I'm going to have cowers valve train and the one of the first blocks done by eagle. I'd like to increase the stoke to about 91.5 mm the 1zz. Now i would prob need and get a forged crank and con rods and custom pistons (goal about 12-12.3 CR). My question is how do i get the clearnce for the pistion and keep the CR from going tho the roof? Can i just use an 1/8th inch headgasket? I mean that should be very close to keeping the valves and pistons sperated by the same distace, since i would only be increasing the upper half of the stroke about 3.25 mm. And that would keep the compression volume about the same. And increase the Volume of air to about 1.98L. So will that work or will i need some crazy profile on the pistons? How realistic does it sound? Probly call JE tomarrow about the pistons.
Thanks guys

[vvtlikick]

I'm no engineer, but I'll give you my opinions :p.

I think 200+ hp at the wheels is doable. (My long-term goal is about 195hp at the wheels)

I think a 91.5mm stroke may compromise the long-term reliability at very high-rpm (I wouldn't move up the revlimit at all), but it'll give you 1.933L of displacement to work with. My goal is a more modest 87mm stroke.

If you preserve the stock combustion chamber volume with your 1.933L engine, you'll end up with a CR of 12.3:1. But I think that's too high for pump gas. I'd stay below 12:1. My goal is a more modest 11.7:1.

Also, the piston at TDC won't be 3.25mm higher, you'll be running shorter conrods, which should account for most of the change in stroke. The wristpin location in the piston could also be moved up slightly. The World Racing Celica moved the wristpin up, but I think that was only to run a longer rod for a better rod/stroke ratio for high-rpm use, they're still running a 85mm stroke.

[Unity112]

Sounds pretty good, icyjaws. I havent necessarily settled on all the specs for when, I build up my engine, however it will be a bit more modest as well.

I left JE's number somewhere on this site, or you can go to thier website, www.jepistons.com. There is also Wiseco who has already done custom pistons for the Celica, and Brian is more than willing to help out.

Unity - who wishes good luck on your project. Keep us updated.

[icyjaws]

Originally posted by vvtlikick
I think a 91.5mm stroke may compromise the long-term reliability at very high-rpm (I wouldn't move up the revlimit at all), but it'll give you 1.933L of displacement to work with. My goal is a more modest 87mm stroke.

If you preserve the stock combustion chamber volume with your 1.933L engine, you'll end up with a CR of 12.3:1. But I think that's too high for pump gas. I'd stay below 12:1. My goal is a more modest 11.7:1.

Also, the piston at TDC won't be 3.25mm higher, you'll be running shorter conrods, which should account for most of the change in stroke. The wristpin location in the piston could also be moved up slightly. The World Racing Celica moved the wristpin up, but I think that was only to run a longer rod for a better rod/stroke ratio for high-rpm use, they're still running a 85mm stroke.
Well first off i forgot to meantion that the skeaves from eagle will prob be overbore possible as high as 83 mm. So 83/91.5 gives me a 1.98L The CR if i keep the same combustion chamber will go up to like 12.7-8:(
No must be looking at something wrong but if i incease the stroke 6.5mm how does 1/2 not go to both ends of of the stoke (TDC & BDC) I would thuoght the distance would be the amount the crank's diameter(don't know what to call it hope someone can help here) Would need to be incrased 3.25 mm therefor moving the TDC and BDC possitions 3.25 mm each. And creating a 91.5mm stroke. Am i wrong? Is this usually done some other way? Thanks again guys

[vvtlikick]

Originally posted by icyjaws

Well first off i forgot to meantion that the skeaves from eagle will prob be overbore possible as high as 83 mm. So 83/91.5 gives me a 1.98L The CR if i keep the same combustion chamber will go up to like 12.7-8:(
No must be looking at something wrong but if i incease the stroke 6.5mm how does 1/2 not go to both ends of of the stoke (TDC & BDC) I would thuoght the distance would be the amount the crank's diameter(don't know what to call it hope someone can help here) Would need to be incrased 3.25 mm therefor moving the TDC and BDC possitions 3.25 mm each. And creating a 91.5mm stroke. Am i wrong? Is this usually done some other way? Thanks again guys Different pistons would easily remedy the over compression problem. And with the bigger bore, your stuck getting new pistons anyway.

If your stroke is 6.5mm longer, but your conrods are 3.25mm shorter, piston location at TDC won't change, piston location at BDC will be 6.5mm lower.

[icyjaws]

yea that makes sense for some reason i was thinking keeping the con rods the same length. So i guess i need to make sure theres enough clearence at the bottom of the sleave (almost sure there is) and just talk to someone about making one for me. Guess i'll start with crower since there getting my head anyway.