I have been told up to 84 is no problem. They have done it already. Difference between 81 and 82.6 is miniscule. Who is a math wiz that could shed some light on this. I saw a post by someone on here recently where the person seemed to know his math, physics. I think he said he worked in F1. He probably would be the one to ask to confirm. I will try to find him and ask. Hopefully he would be kind enough to shed some light on the matter.

You have to remember that even though we are increasing stroke and bore size, because we will use a significantly smaller rod journals, a lot lighter rods, pistons, the roating mass will be very close to stock stroke if not lighter. If you opt for titanium rods it will definitely be lighter. 6 Titanium rods roughly weigh as much as 4 steel ones.
Pistons will be quite a bit lighter as well.

If I owned a GT3, I would try to pick up as much displacement as I could. But that's me

Sorry guys, it seems I had a Brain Fart there with the .6 specs
What I should have done was .4 calculations so here it goes:

GT3:

- 80 x 104.1 = 4085cc
- 80.4 x 104.1 = 4106cc
- 81 x 104.1 = 4136cc
- 81.4 x 104.1 = 4157cc
- 82 x 104.1 = 4186cc
- 82.4 x 104.1 = 4208cc 4.2
- 83 x 104.1 = 4238cc
- 83.4 x 104.1 = 4259cc
- 84 x 104.1 = 4289cc (MAX recommended)

TURBO & GT2:

- 80.4 x 102.6 = 3988cc
- 81 x 102.6 = 4018cc 4.0
- 81.4 x 102.6 = 4038cc
- 82 x 102.6 = 4068cc
- 82.4 x 102.6 = 4088cc

Hey Jay,

Hope you had good trip.

Keyser already made the quote that it revs like a "dentist drill" but remember that build was a 105.9 bore x 79mm stroke 4.2

I don't think I can justify paying an extra $4500 for titanium rods when I think the steels will be enough. I will probably go with some crank work though just to lose a bit more weight and will do all the coatings for sure.

Adam, are the JE pistons able to take the increase in compression of 12.5.1 or 13.1 that us N/A boys will require ?

Cheers
Dave

JE is one of the best piston manufacturers out there. Their pistons will easily handle the 12.5-13.1 compression. I do recommend the piston skirt coating for sure to give me a piece of mind. I am not a huge fan of the thermal barrier coating. I did it in one of my 3SGTE motors and it seemed the motor could not handle as much timing as before. Combustion chambers were getting a lot hotter; the heat could not dissipate through the pistons. Anyone else with experience with piston top, thermal barrier coating? I would love the input of some of you who has also done it. What do you think about it?

With 105.9mm bore, I would think the additional weight being at the outer end of the rotating mass is worse that having more stroke. I would like to point out again that even though the stroke might be 82, or even 84, the cranks are going to be lighter at the rod journal end than stock stroke; the stroker cranks will be lighter than stock stroke, stock cranks.

I also just learned this morning at Cars n Coffee, that JE will have the Asymmetrical pistons available in 104mm sizes. I will have to confirm. I don't know if those will be better than the FSRs but I will find out to make sure. Come to think of it, I think Asymmetrical pistons are better for Turbo applications. I don't know if they are available in 102-103mm sizes.

Thanks Adam,

Whatever the recommendation is for the pistons I'm happy to go with. Plan on running the uprated clutch and LWFW anyway, so with a bit of extra weight off the crank and the lighter pistons as well it shouldn't be a problem.

I will also do the piston skirt and bearing coatings for sure.

Cheers
Dave.

I went with a aluminum 12lbs flywheel myself and made the mistake of going with an unsprung clutch disc which makes a lot of noise. I will not recommend that to anyone. Kinda annoying!! Almost sounds like a multi disc Exedy we had in my brother's EVO. Go with a sprung disc.

I actually have a clutch suggestion for you. They come with super light weight flywheels and smaller diameter multi disc clutches. I haven't been able to talk to them thanks to holidays but I will try and contact them after the new years.$2550 for 3 disc one.

Adam,

I'm interested in this clutch, I was just about to pull the trigger on a 4.0 clutch and LWFL.

I can vouch for JE pistons, used them on many race applications, both NA and supercharged, strong, reliable and light. I can't comment on the asymmetric pistons, would like to know more.

Cheers
Jay

I don't know. The old girl revs pretty good despite having been built to the wrong specs as has been stated.
Champion Motorsport made all happen. The was extensive machining done not just parts.


Here's what the motor put down. Look at the torque curve.



\m/

Who said anything about it being built to the wrong specs ?? All of the builds I have seen including yours have been with a 105. something bore and kept the stroke under 80mm.

I would go as far as to say your build IS the benchmark

Here's the triple disc CF clutch utilized.



\m/

CMW made a 4.2L 993 Air Cooled with 84mm stroke. They're 997 stroker kit is 84mm as well... So the smaller rod journal clearance has been done successfully before with bigger stroke than we're playing with. Important thing is to use proven parts, the crank being the most critical in my opinion...

Nice numbers Keyser. Sounds awesome!!
What are the correct specs if you don't mind me asking? How about just the bore.

I will find out about the clutches soon and let you know Jay.

I just heard of these sleeves where there is no machining involved; drop in sleeves, but max bore is 103. I will find out a little more after the new years. Will not effect the cranks; won't change anything. Depending on the stroke you will pick the rod length will change slightly.
103 x 84 = 4199.5 (4.2)

If this is available, it might be a great compromise; it will eliminate the machining involved with the installation of the bigger bore sleeves, and take some of the hard work involved out of the equation.

For those of you that want the most out of the build 84 x 104.1 = 4289.7cc and don't mind the extra machining involved then the 104.1 is the bore to go with.

Adam,

I have mentioned this build numerous times in this thread. Champion were kind enough to post some of the build details on a separate thread.
Bore 105.9mm x 79mm stroke.

Don't get me wrong. Thanks for that bit of info. I just wanted to get a confirmation from Keyser. I am sure they provided him with a build sheet after his motor was built. That's all. I thought maybe he went with a different setup…

105.9 is a large piston. Wonder what sleeves they used??
Those are some great numbers his motor put down too!

Who knows Keyser best? Take him out, get that man some drinks so he spills the beans