FRS / BRZ Intake Manifold - Development Thread - FT-86SpeedFactory by Velox

[celek]

Originally Posted by WHITE

Gotcha, I was hoping for something still using a fa20. Fb25 Seems like a big trade off for just .2liters more then a bored and stroked fa20.

Greddy TODA and HKS crank are all at 90mm stroke
FB25 is 90mm stroke but the actual width of the rod bearing is around .500"

The above mentioned after market cranks are using a RB26 SR20 rod journal if I recall at .650 wide same 48mm journal. over 20% more oiling surface area

FB25 uses a 94mm piston to make up the difference to get the extra .2 ltr vs a sleeved 90mm FA20 block at 2.3ltrs

That is a lot more mass in an unsquared piston to stroke to try and rev. Additionally the rod to stroke ratio on the FB 25 is 1.41:1 vs 1.50:1 on the FA20
The infamous Honda B16 runs a 1.75:1 with that factory 8200 Redline just to put it in perspective.

Not to go way off subject but the reason the FA20 makes 200HP at 2.0ltrs is because how light the internals are. Start adding weight to components the outcome may not exponentially increase i.e adding 25% displacement may not equate to 25% more power.

[burdickjp]

Originally Posted by celek

Not to go way off subject but the reason the FA20 makes 200HP at 2.0ltrs is because how light the internals are. Start adding weight to components the outcome may not exponentially increase i.e adding 25% displacement may not equate to 25% more power.

That's a rather severe oversimplification, and not at all true.

[WHITE]

@celek im sure there is a way to bore a fa20 to 94mm. The current darton sleeves have a 4" O.D. So boring them to 94mm(3.7") leaves only a .150" cylinder wall. But if we were able to fit a 4.25" O.D. sleeve into an fa20 then a 94mm bore would have a .275" cylinder wall wich would be more then thick enough for even boosted applications.


For comparison a current darton sleeve bored to 90mm has a wall thickness of .2285" and is said to handle 50+psi.

I'm probly going to look into this more once I start building my engine, if anything though ill be same as you with a 90mm squared stroker, just boosted instead.

[celek]

Originally Posted by WHITE

@celek im sure there is a way to bore a fa20 to 94mm. The current darton sleeves have a 4" O.D. So boring them to 94mm(3.7") leaves only a .150" cylinder wall. But if we were able to fit a 4.25" O.D. sleeve into an fa20 then a 94mm bore would have a .275" cylinder wall wich would be more then thick enough for even boosted applications.


For comparison a current darton sleeve bored to 90mm has a wall thickness of .2285" and is said to handle 50+psi.

I'm probly going to look into this more once I start building my engine, if anything though ill be same as you with a 90mm squared stroker, just boosted instead.

Problems with 94mm bore is we are dealing with DI larger the bore higher the CR at the same dome Easily fixable with custom pistons.
Additionally DI is very picky on the quench minor changes can hinder power production. I would also be concerned with losing cooling efficiency shrinking the jackets volume. Lots to consider.

Originally Posted by bur****jp

That's a rather severe oversimplification, and not at all true.

I wanted to keep the thread on its original subject and drop the highjack, without going into mathematical calculations of proportional displacement to component weight ratio's

Now back to the INTAKE MANIFOLD!

[burdickjp]

Originally Posted by Tim Radley

I wouldn't worry about the cutout in the piston top, its not critical. I've removed them on Audi builds and made over 700bhp.

One example does not make a generalization.

[celek]

Originally Posted by Tim Radley

I wouldn't worry about the cutout in the piston top, its not critical. I've removed them on Audi builds and made over 700bhp.

Can't compare turbo to NA though

[wootwoot]

Stay focused people.

[Captain Snooze]

Originally Posted by wootwoot

Stay focused people.

But but but... the anticipation!

[dem00n]

I'm confused why this topic is keep being bumped. Didn't they already state the manifold isn't great for NA applications and are going towards FI applications? Should this thread to be moved to Forced Induction?

[Calum]

Originally Posted by dem00n

I'm confused why this topic is keep being bumped. Didn't they already state the manifold isn't great for NA applications and are going towards FI applications? Should this thread to be moved to Forced Induction?

Hope is a powerful foe. Desperation an even worse enemy.

[plucas]

Originally Posted by dem00n

I'm confused why this topic is keep being bumped. Didn't they already state the manifold isn't great for NA applications and are going towards FI applications? Should this thread to be moved to Forced Induction?

I think the thread is in the correct location

[dem00n]

Originally Posted by Calum

Hope is a powerful foe. Desperation an even worse enemy.

Trust me, I'd like to believe this will work, but he did say this.

Without giving 2much (haha) away, like we suspected it does not work well with an NA application. It loses some power mid-range but actually picked up power downlow, didn't see that coming.

We're moving onto FI testing which is what this manifold was designed for.

We have another idea for NA application we want to test once funds become available .

http://www.ft86club.com/forums/showt...=60125&page=10

[Captain Snooze]

Originally Posted by NotEric6

like we suspected it does not work well with an NA application.

Head (and heart) is sad, wallet breathes a sigh of relief.

Originally Posted by NotEric6

We have another idea for NA application we want to test once funds become available .

Arrrrggghhhh!!

[Calum]

Originally Posted by dem00n

Trust me, I'd like to believe this will work, but he did say this.

Without giving 2much (haha) away, like we suspected it does not work well with an NA application. It loses some power mid-range but actually picked up power downlow, didn't see that coming.

We're moving onto FI testing which is what this manifold was designed for.

We have another idea for NA application we want to test once funds become available .

http://www.ft86club.com/forums/showt...=60125&page=10