[SuperRunner]

If I am looking for 750RWHP, do I really need bigger valves?

My soon to be brother in law is the port and polish guy at a local machine shop, so basically, I am getting it done for free, along with the lower intake runners extrude honed. I will run a custom intake manifold, and probably the 272/272 cams.

Will I really see much of a gain, and if so, how much of a gain using larger vavles. If your torque drops off over 7K, why would you need to accelerate past that, so who cares about horsepower. So what, at 8K I may push another 50-75hp, but it won't make me faster in the 1/4 mile.

I have searched, and people just said......Oh, you should do it anyway, but nobody ever posted any results.

 

[VeilsideTT]

Hell, I'd do it if it was free. Remember that if HP increases so does torque. Also, HP at higher speeds does help the car move down the quarter.

 

[SuperRunner]

The labor is free, the parts are not.

I would still have to buy valves if I want to go bigger.

What type to most people go with.

I have seen

Manley
Powerhouse
overboost

and I am sure there are more.

 

[silvino]

I went with Ferrea and i've seen lots of other folks use them as well.

The labor is free, the parts are not.

I would still have to buy valves if I want to go bigger.

What type to most people go with.

I have seen

Manley
Powerhouse
overboost

and I am sure there are more.

 

[LMBLF8]

I went with Ferrea and i've seen lots of other folks use them as well.

Good Stuff

 

[KenHenderson]

The labor is free, the parts are not.

I would still have to buy valves if I want to go bigger.

What type to most people go with.

I have seen

Manley
Powerhouse
overboost

and I am sure there are more.

SuperRunner,

If your goal is 750 whp, know this. I made 789 whp and almost 625 lb ft with stock size Ferrea valves. I did this with an extrude honed stock manifold, extrude honed and ceramic coated turbos (twin GReddys) and a 90 mm VeilSide titanium exhaust at 1.95 bar. I also have 272 cams, JE .040 pistons and head work, which I'm sure contribbuted to these power levels as well. I'm not saying bigger valves don't work. They obviously do but, so far, I'm not convinced its absolutely necessary with our motors, assuming you accomplish some other flow enhancing tricks. I was more concerned about port velocity (although this may not even be an issue) so I went with the stock sized Ferreas. Hope this helps.

Ken.

Ken.

 

[SuperRunner]

SuperRunner,

If your goal is 750 whp, know this. I made 789 whp and almost 625 lb ft with stock size Ferrea valves. I did this with an extrude honed stock manifold, extrude honed and ceramic coated turbos (twin GReddys) and a 90 mm VeilSide titanium exhaust at 1.95 bar. I also have 272 cams, JE .040 pistons and head work, which I'm sure contribbuted to these power levels as well. I'm not saying bigger valves don't work. They obviously do but, so far, I'm not convinced its absolutely necessary with our motors, assuming you accomplish some other flow enhancing tricks. I was more concerned about port velocity (although this may not even be an issue) so I went with the stock sized Ferreas. Hope this helps.

Ken.

Ken.

Why ferreas over stock? Do they flow better, or lighter wieght, or do you need a shorter valve with the 272.

 

[Boost Junkie]

If I am looking for 750RWHP, do I really need bigger valves?

No. People have made 900-ish to the wheels on stock valves without nitrous. 750 is a piece of cake.

If your torque drops off over 7K, why would you need to accelerate past that, so who cares about horsepower. So what, at 8K I may push another 50-75hp, but it won't make me faster in the 1/4 mile.

This is a common misconception -- that there is no benefit to spinning past the torque peak. Here's a link to an excellent writeup on why HP is important, and why spinning to a higher RPM is useful for acceleration:
http://www.boostaholic.com/hptq.html

Steve Hayes

 

[MK4LIFE]

1mm oversized ferrea valves here

If your building the head, do it right the first time. Do the valves, springs, retainiers, ect... That 750rwho you speak of wont last long, and you WILL want more

 

[Axoman]

I agree with Ken, as I don't think I've seen enough (any) proof that oversized valves gain much power. It would be nice to see results from before and after, but any time I have seen results, it's been from a stock head to a ported head and oversized valves.

 

[Guest]

I agree with Ken, as I don't think I've seen enough (any) proof that oversized valves gain much power. It would be nice to see results from before and after, but any time I have seen results, it's been from a stock head to a ported head and oversized valves.

i know its not the same but im putting the 1mm oversized ferra's on my 7m.. im mainly doing it to get higher revs but if you have a 2jz then you dont really need to worry about that... but i guess if you have it all apart and have the money to do it... go for the best

 

[Superb Supra]

I've noticed everyone is always going 1mm over sized, would 2mm+ ever be necessary?

 

[cowboy bebop]

I'm going to be pushing MONSTEROUS amounts of air though the head when the new configuration is complete and we're only going with 1mm oversized. 750 on stock valves is not an issue, as I've made 891 rwhp on them, and honestly, if that's you're final goal, I'd not even do it. It'd only be bragging rights.

Eric

4 digit HP

 

[SuperRunner]

Thanks, that is what I needed.

Stock valves it is.