Highest-revving SOHC automotive engines?

I bet Wiseco would do it.

I'm still boggled by the factory pistons having 4 valve reliefs...

Zomby Woof wrote: FWIW, I recall those 3V motors not behaving much differently than the 2V ones they replaced. You'd think, with all that intake valve area that you'd have to be really careful with inlet timing, but apparently that's not the case. Treat it like you would a 2V.

Any ideas why that's the case? Port size in the head or manifold the limiting factor, and not the valves? Seems odd.

On the piston topic.. what do those look like? My favorite pistons are flat on the top with valve reliefs, but that's not always possible!

Posted a pic of the pistons above you.

Dish for days and lots of valve relief for a 7.8:1 motor.

It's a non-interference motor, possibly because of those reliefs, and the car gets great mileage so I'm not sure if it's really so bad after all. Remember that these were tied to a not so hot transmission and a lot of the F2T's were in sedans.

Add some lift/duration and it's probably not non-interference anymore.. 7.8:1 is good for an 87octane contest, but this is 2013! If you really can get good swirl going with this head I'd be certain there's lots of room to go up in compression to help things along.

PS... with all those reliefs a 16v head starts to make more and more and more sense.. why is that a bad idea again?

I'm a little worried about the 16v decreasing torque and/or slowing down spool. These motors spool gigantic turbos way faster than they have any right to, but i know this is a double edged sword.

However, i talked somewhat briefly with a guy in Puerto Rico (Surprise!) who had done the FE3 head swap on an F2 bottom end, using 3sgte pistons of all things, used a mid-sized T4, and ended up making obscene power on impressively low pressure numbers. 20psi i think. I wasn't really a huge fan of the torque number, though.

Quote with some of the info:

No problem in help others, you have to weld the two discharge holes in the corner of the head, use only the one in the middle is the one you have oil pressure and oil return, use toyota mr2 pistons,I used cp pistons part # sc7450, and it still have that low end torque very good already I made 534 whp and 389 torque I think I can have closed to 600 whp but I will know that in about a month, any question feel free to ask.

End of the day, going to a 16v head probably isn't a bad idea at all. But... i have 3-4 spare 12v heads and they're a lot easier and cheaper to source parts for. Plus.... it's weird and strange and stupid, so i like the idea of it.

Is the spacing of the valves in the F2 head exactly the same as in the 16V, but for one missing? Do we know if the F2(T) pistons would play nice with the 16V head?

JamesMcD wrote: Is the spacing of the valves in the F2 head exactly the same as in the 16V, but for one missing? Do we know if the F2(T) pistons would play nice with the 16V head?

Not sure. Wondering if that's why the PR guy used 3sgte pistons. I wasn't sure if it was due to that or maybe the compression ratio being too low with F2 pistons.

Maybe the ones he used are of a more modern design which takes into consideration the effect of quench and biasing the mixture towards the exhaust and such-like.

These are what he used....

http://www.theboombopshop.com/CP-Pistons-Toyota-3SGTE-p/sc7450.htm

Whut? That looks like a 2V piston to me.

I found the one he used and it looks like a flat top piston with 4 valve reliefs.

Arg. My mistake. Updated.

They are dished, though... probably sit higher than the F2 stuff.

A 16V head should be better in practically every single way.

Paul_VR6 wrote: ZW shooting you a PM on an unrelated topic, pls reply if you can. Thanks.

Not seeing it.

The f2t spools big turbos faster than the fe3, though. It may not take advantage of them up top, but that is one thing it does better than the fe3.

Swank Force One wrote:

It might be useful to get the weights/dimensions of those rockers and compare them to engines that you know don't explode at 9,000 rpm. The setup looks vaguely d series Honda-ish to me, so that's probably a good sign, but you do have the head sitting at home.

Zomby Woof wrote: A 16V head should be better in practically every single way.

Agreed and I can't see a situation where it wouldn't be better. Could the "quicker spool" be caused by other things inherent in the setup and not the head design?

Zomby Woof wrote: Not seeing it.

Sent again, it should go to the email that you registered here with. If you don't see it just shoot me an email to kandpperformance at gmail dot com Thanks.

Paul_VR6 wrote:

Zomby Woof wrote: A 16V head should be better in practically every single way.

Agreed and I can't see a situation where it wouldn't be better. Could the "quicker spool" be caused by other things inherent in the setup and not the head design?

Zomby Woof wrote: Not seeing it.

Sent again, it should go to the email that you registered here with. If you don't see it just shoot me an email to kandpperformance at gmail dot com Thanks.

Exhaust velocity is substantially higher on the F2 vs. the FE3. We're building 30psi of boost before 4000rpms on Holset HX40s.

That's not happening on an FE3.

In reply to Swank Force One:

I'm curious what a chassis dyno curve looks like with the above mentioned HX40/30psi @ 4,000 RPM situation with an F2T. Even with the factory broomstick camshaft, that should make somewhere around "stupid" power numbers, yes?

Gear this thing like it's a Buick 455, that's my take-away from all of this.

The FE3 might be more efficient at that rpm and be making less boost, but making more power. Think about it this way, the more efficient it is, the more air volume is necessary to make a certain amount of boost. You might think it's "lag" or a lack of spool, but I think that behavior could be inherent in a setup that just flat out makes more power. I think it would be worth looking at dyno graphs of both motors with the same turbo at the same boost and seeing what the power and boost ramp curves look like.

pres589 wrote: In reply to Swank Force One: I'm curious what a chassis dyno curve looks like with the above mentioned HX40/30psi @ 4,000 RPM situation with an F2T. Even with the factory broomstick camshaft, that should make somewhere around "stupid" power numbers, yes? Gear this thing like it's a Buick 455, that's my take-away from all of this.

Yeah, it should.

The problem is that the HX40 guys and the even bigger HE351VE guys never dyno'd their cars.

The closest we have is that HX35 car @ 26psi.

http://youtu.be/HxF7a3LYr9M

He later went back and leaned the car out a bit (stupid rich in that video) and it made 483whp/547wtq.

His curve is actually pretty decent, but there's a lot of room for improvement. I don't think the F2 head would keep someone from making say.... 600whp, but it may very well keep someone from making it in a higher rpm range, or may keep it from revving at all.

Paul_VR6 wrote: The FE3 might be more efficient at that rpm and be making less boost, but making more power. Think about it this way, the more efficient it is, the more air volume is necessary to make a certain amount of boost. You might think it's "lag" or a lack of spool, but I think that behavior could be inherent in a setup that just flat out makes more power. I think it would be worth looking at dyno graphs of both motors with the same turbo at the same boost and seeing what the power and boost ramp curves look like.

That's going to be hard.... there aren't many examples of dynos for either motor, unfortunately.

There's been 1000whp FE3 drag motors, there's been 600whp FE3 street cars, blah blah blah... but none of them put up the torque numbers the F2T does. Does that necessarily mean the F2T makes more power? Nah. But it certainly does at certain RPMs.

I'm not against the FE3 idea, but the original point of the discussion was SOHC, because i happen to have a bunch of those heads already and they're dirt cheap and simple to work. (Though when i say "point," i mean the term pretty loosely. I can make more power than ever necessary on a "normal" F2T in the first place.)

FE3s.... not so much.

Swank Force One wrote: Intake valve diameter: 32.5mm Exhaust valve diameter: 34mm Here's some pictures of the head. i happen to have a bunch of those heads already and they're dirt cheap and simple to work.

first thing I'd do... is cut up a few chambers and find out where the casting ends.

Id cut each in half... then each half I'd cut up differently. If you can afford it (additional head to cut), make sure any discrepancies you see are in multiple heads.

The exhaust ports looks like there is PLENTY of meat... the intake... not as much.... this might be why this head works down low... because intake port velocity is quite high??

The pistons I've seen so far, in this thread, don't seem to utilize much squish. What if you were to build pistons to utilize the large squish pad (where 4th valve would be)?

Ben, I wanted to throw out a tidbit only obliquely related to your thread here:

The F2T has only 9% more total intake valve area than the FET... While the FET has 12% MORE total exhaust valve area than the F2T.

Interesting huh?

You know... there was an old thread I remember on mx6.com now that you just jogged my memory.

Some of the old timers were talking about how the FET was probably a better motor in many ways.

There's something for me to look at.