Bigger Valves

[ozzimark]

The thread is underway... Don't hold your breath. Time to go mix up a nice gin n tonic so I don't shoot myself for watching myself type the nerdiest stuff imaginable :lol:

Very well then, I'll continue my research so that I have something to say that could pass as being something that's not a stab in the dark :lol:

Chow, what exactly are you trying to do that you want larger valves and decreased CR? I never really thought about it earlier, but now that I do, it boggles me. Your head with a port and polish won't be restrictive when paired up with a 19T. You'll run out of flow from the compressor before much of anything happens with larger valves. If you were shooting for much higher power, I would understand significant modifications to the head, but you'll need a much larger turbo for that

Don't take me the wrong way, just trying to make sure you have your priorities straight :D

[shaun]

I would like to understand more about timing on pent-roof chambered cars... Maybe I'll start one? I know the basics on timing and the general guidelines.. But it would be interesting to try to ferret out opinions of people who have tuned these things on a dyno before. Hm.

Maybe you have seen this site already, but Larry Widmer has done lots and lots and lots of head work and describes the various chamber sets up at length.

http://www.theoldone.com/articles/

[GeraldJ]

Maybe you have seen this site already, but Larry Widmer has done lots and lots and lots of head work and describes the various chamber sets up at length.

http://www.theoldone.com/articles/

I cant believe that site is still around. I was using that about 10+ years ago when building d series honda motors was the thing to do.

[shaun]

Mayby this is a better page to start in on

http://www.theoldone.com/archive/

[johnloves850's]

i didn't read this anywhere in the thread, but why are you doing this much head work

when you could be getting some nice rods in and just skip right to a ball bearing set up?

although, this is definitely a good idea, it just seems kind of out of order to me

the better your head is, the longer it will last under high boost

oops, sorry about that ^

yea i would get eagle rods, that's what all my friends use that run high boost

although the don't have volvo's haha, who'd a thunk it

[Chow]

Very well then, I'll continue my research so that I have something to say that could pass as being something that's not a stab in the dark :lol:

Chow, what exactly are you trying to do that you want larger valves and decreased CR? I never really thought about it earlier, but now that I do, it boggles me. Your head with a port and polish won't be restrictive when paired up with a 19T. You'll run out of flow from the compressor before much of anything happens with larger valves. If you were shooting for much higher power, I would understand significant modifications to the head, but you'll need a much larger turbo for that

Don't take me the wrong way, just trying to make sure you have your priorities straight

Ozzimark,

Thanks for you input... I'm just trying some off the shelf ideals..... I wanted to have bigger valves to increase power and later down the road have it on tap so I don't have to open the head back up.. as far as the turbo goes I just wanted something that could bolt on right now and now screw with a down pipe... I work at a dealership so thing like bolt on stuff come cheap.... just messing around this some ideal and seeing if they work out..... oh ya as far as the fuel and air mixture goes, I should have that covered too

[lookforjoe]

Joe, no hard proof, but really there is no reason you would have any issues with detonation or pinging at 8.5 CR if you/your tuner knows what is going on with ignition timing and AFR. And as you implied, a free flowing setup is critical, especially on the exhaust side to keep EGTs down. If you wonder why I say that 30psi is possible, consider your setup.. You have an off-the shelf tune with a restrictive turbine running pretty well up to 24 psi, no?

The name's Hussein, not that you would know that "joe" is the fella in my avatar

I haven't really pushed above 24psi based on what others have said re head gasket failure; it is obvious from the EGT's I was getting on wot runs that above 24psi, there is no gain in power with the 19T, just more heat. However, I haven't checked the EGT's again with my WI install. The IPD tune is apparently pulling timing once I hit 3K - see my Mustang dyno charts (still waiting for a reply from IPD on that). On the Boston run, it was clear that power drops off (even with the WI), as I was hard pressed to stay ahead of Ben's white 850T5 (stock w/ACV-R boost control) in the upper rpm's :D

[ozzimark]

Ozzimark,

Thanks for you input... I'm just trying some off the shelf ideals..... I wanted to have bigger valves to increase power and later down the road have it on tap so I don't have to open the head back up.. as far as the turbo goes I just wanted something that could bolt on right now and now screw with a down pipe... I work at a dealership so thing like bolt on stuff come cheap.... just messing around this some ideal and seeing if they work out..... oh ya as far as the fuel and air mixture goes, I should have that covered too

Bigger valves isn't exactly off-the-shelf. If you want to stick that route, get an R manifold, port and polish head and manifold, get a larger turbo with opened up exhaust, get some tuning, and you have the basic recipe that many others who have modded their cars for more performance here have done. While not terribly exciting, it's the easiest way to go about getting what you want.

If you want to go extreme, I would advise looking to see what the notable build thread shows, and try to take it a step further than that

The name's Hussein, not that you would know that "joe" is the fella in my avatar

I haven't really pushed above 24psi based on what others have said re head gasket failure; it is obvious from the EGT's I was getting on wot runs that above 24psi, there is no gain in power with the 19T, just more heat. However, I haven't checked the EGT's again with my WI install. The IPD tune is apparently pulling timing once I hit 3K - see my Mustang dyno charts (still waiting for a reply from IPD on that). On the Boston run, it was clear that power drops off (even with the WI), as I was hard pressed to stay ahead of Ben's white 850T5 (stock w/ACV-R boost control) in the upper rpm's

Hahaha, sorry about that. I tend to assume things without thinking about it, especially because my name is pretty obvious from my user name

But yeah, on the 19T... flow.

I wanna see what you pull off with that 20G and a revamped tune from IPD, whenever they get back to you :D

[Guest 300+_T5R_855]

On a side note, you can lower effective compression ratio by retarding the intake cam timing. The intake valve will spend more time open while the piston is traveling upward on its compression stroke.

Albeit inefficient.

The S60 head gasket offers some additional that if taken advantage of, to increase overall engine efficiency.

It could get very expensive putting bigger valves in one of these heads because of interference. To be done correctly could be very time consuming.

[shaun]

I'm having my head sent out and wanted to put bigger valves in it. I've doing some searches but don't really seem any talking about it. I have a 1998 S70 T5 engine. From what I have gathered, you can go with a 44mm intake valve and a 40mm exhaust valve..... Is this a good set up? Over kill or for not for street???

So far I'm having my turbo sent out 16t and putting a 19t wheel in it, S60r headgasket, S60r exhaust manifold, N/A cams, and rods (not sure which ones yet) is there anything else you guys can think of???? Oh ya, I'm also looking for a set of green injectors too

Thanks

One point to consider with bigger valves is they do not necessarily gain any flow if you just stick them in there without making sure they have room to put charge. They might just end up shrouded against each other and the diameter of the combustion chamber/cylinder diameter. Flow needs to be approached systemically, velocity/chamber shape/fuel/pressure/timing/bore...... Work with someone who really knows this stuff, dropping in big valves might feel good but get you nothing.

[EricF]

Shaun, over the years I have spent a great deal of time over there at Larry's site, and I miss that messageboard dearly

One thing I have been interested to see (and since starting that other thread, have gotten to see more and more of it) are how ignition timing tables for pent-roof chamber cars can compared to the big chamber 2-valve flat roof chambers I am used to working with timing on. Flow-wise, I feel pretty good about my understanding and I think you are absolutely and positively right about bigger valves.. Already I think there is some shrouding going on with the stock valves at higher lift in some places in the chamber.

[shaun]

Shaun, over the years I have spent a great deal of time over there at Larry's site, and I miss that messageboard dearly

One thing I have been interested to see (and since starting that other thread, have gotten to see more and more of it) are how ignition timing tables for pent-roof chamber cars can compared to the big chamber 2-valve flat roof chambers I am used to working with timing on. Flow-wise, I feel pretty good about my understanding and I think you are absolutely and positively right about bigger valves.. Already I think there is some shrouding going on with the stock valves at higher lift in some places in the chamber.

I spent a week reading everything Larry wrote (and a bunch of otherr stuff) before spending a couple hours with the a local guy who helped me port my civic d16y 8 head. that was just for what I would call a "stage 1". the 96-00 D16 pent roof looks quite a bit like these modular whiteblock heads.

Your thread on tuning is what this site needs allot more off. killer stuff.

Concerning combustion chamber design, BMW is running an magazine add that shows one of their current heads and the geomery of the chambers is very very complicated- lots of science going on in engine design these days.

[Zulu]

i didn't read this anywhere in the thread, but why are you doing this much head work

when you could be getting some nice rods in and just skip right to a ball bearing set up?

although, this is definitely a good idea, it just seems kind of out of order to me

the better your head is, the longer it will last under high boost

Well since the head is a limitation once you get over 350whp...

[Boost3237]

i didn't read this anywhere in the thread, but why are you doing this much head work

when you could be getting some nice rods in and just skip right to a ball bearing set up?

although, this is definitely a good idea, it just seems kind of out of order to me

the better your head is, the longer it will last under high boost

oops, sorry about that ^

yea i would get eagle rods, that's what all my friends use that run high boost

although the don't have volvo's haha, who'd a thunk it

the head is the reason we have to boost so much to make a difference with out cars, it is a major limiting factor. if you do rods and pistons it would be ludacris not to do some head work too. I mean you dont have to but the benefit is so worth the cost.