I think the stooks compression ratio is around 11:1 right? I have been following the HP quest some guys are on and it just hit me. from my observations cars that take boost well have lower compression ratios generally. Why not lower the compression to a suitable level....say 9.5:1 and then add good solid boost. if this does not work, then why not. I am curious. the miata's engine take boost quite well, I think up to 6 pounds without mods. It really is overbuilt for it's application. I was just curious as to the methods for adding boost to an already radically reinforced engine.

thanks for any input you may have.

 

The F20C can handle 6-8lbs of boost without lowering the CR, but over that things get iffy. Truly, there is really no need to lower the CR, with 6lbs of boost on tap it'll produce 330 odd HP at the wheels .

Andrew

 

DAMN!! That's too much power for my blood.

 

I'd say the biggest reasons are lack of parts and high expense. I don't know if anyone even makes low compression heads for the s2000. Thicker head gaskets aren't the best solution and don't work well for lowering compression a lot. Bottom end work is the best bet, but any of that is expensive. I've heard something like $5000 for a new crank? Is that right? Nobody wants to spend as much on the engine as the turbo just so it can take more boost. And after all that work nobody really knows how strong the bottom end is. Would it really be worth all the expense lowering the compression when the stock block might blow up with small amounts of boost. Given that lightweight was an important goal with the F20C that is a possibility. Anyway, I'm sure if there were enough demand it would happen, but this brings up another point:

The s2000 is already fairly quick and many people are happy with the car the way it is. The existing turbo kit running at low boost is already plenty fast. The more power you put into a car the harder it becomes to turn the car without overpowering the wheels. If you want to go *really* fast it's probably better to start with a different car. A big part of the cost and attraction of the s2000 is due to the chassis and suspension. Too much power effectively throws all that away.

 

does je make pistons for the f20?

the s2000 engine would be prefect for turbo, maybe a 10.1 compression and 8-10 pounds of boost, so much top end.. the engine has the torque to spool the turbo, when vtec crossed over..i think it would scare you .

jordo

 

You wouldn't need a crank, and JE/SRP will make pistons to order. The only hefty exspense would be labor. As for head gaskets, they can effectively lower compression a half point easily with no worries...

 

Keep in mind the actual compression is not the reason you can't boost more... it's detonation.... lower compression is just one of many tools used to combat detonation.... many many many high power engines have been built with over 10:1 compression and still safely run a lot of boost... compression is just one of many factors which I would assume could include quench areas to valves to fuel used....

 

The earliest attempts to turbo an F20C reported they were re-sleeving the block with ductile metal cylinder linings as part of the effort to reduce compression (reducing detonation). Haven't heard much success in those kits but it sounded like the way to go for a monster-motor.

Nobody said much about this but, does "water injection" help avoid detonation? That's a resonably cheap mod with a long history.

 

[QUOTE]Originally posted by Penforhire
[B]Nobody said much about this but, does "water injection" help avoid detonation?

 

First of all, lemme say you can always run more boost. Maybe your car can't handle it, but YOU will always like the feeling. That being said...

I'm running 10 psi on race gas now, no problems, although since everything is so loud I would like to be able to tell if anything is detonating under boost. Maybe an aftermarket knock sensor..

Anyway, speedcraft is in the process of creating a metal head gasket which lowered compression by nearly a full point (10:2:1 I believe), and I'll be bolting that onto my ts2k as soon as dwight (the mechanic at speedcraft) can get me one. With new pistons and potentially rods, I may go to 12 or 14 psi, depending on when this is (I'd still like to get at least another year of sturdy daily driver out of it). A year down the line and we'll see what happens.

cd