Photos of turbo 3.0 setups

[Ondonti]

+2mm intake +1 exhaust.

I personally dont think larger exhaust valves help because a good exhaust port is 95-100% the size of the face of the exhaust valve, and with all my port work, I went from like 60% the size of the valve to about 88% or so compared to the stock valve.

The valves are using Ferreas most expensive stainless setup. Thats basically what I had to do.

If you want valves you might want to wait till they finish mine. They said the price might go lower after they finish raping me.

[c2xejk]

For a turbo, I would recommend +3mm exhaust valve and stock sized intake...

On a turbo application you need bigger valves to have good balance between the intake and exhaust. The general rule of thumb for a turbo is intake valve * 0.9. 43 *0.9 = 38.7 or +3.7 mm. You are starting to get to the size limit, so I would round down...

Based on my experience with stock valve porting on this head, I think this can be done... Tight, but I believe doable, IF you know what you are doing and were the limits are...

That said, I have not yet tried this on my combination on my flow bench. So I could be wrong... And as always, the engine is the ultimate judge of what is good and what is bad...

[Ondonti]

I still go by the idea that a bigger valve cant help a port that is too small.

[c2xejk]

I think I can get it big enough. Too big and you lose flow and kill hp... Some big hp has been made by what most of us would consider way too small of a port...

[Ondonti]

Quote:

Originally Posted by c2xejk I think I can get it big enough. Too big and you lose flow and kill hp... Some big hp has been made by what most of us would consider way too small of a port...

I know the exit of the port is too big, but the rest of the port is about 66% of the size of the exhaust valves. You could probably install a exhaust valve that was 3mm smaller and the port flow would not change. Exhaust ports make the most power when they are 95-100% the size of the exhaust valve. (this of course is not counting the neckdown around the valve). I stick with what graham says on that. He is not a flowbench guy, but a man who does back to back dyno work and has ported countless heads. The intake.....I agree the ports are too big for the stock valves and cant really be ported to make much of a gain.

Also, the idea that an exhaust valve must be quite large is an Idea I do not agree with, even when it comes to turbo cars. In theory it might sound good, and it might work great on the flowbench. Exhaust reversion problems should not have to be fixed by handicapping your intake valves, but should be fixed by improving the exhaust port, the exhaust manifold, and getting a turbo that doesnt create massive backpressure. Larger Intake valves bring extra power and unlike just about any other mod in existence, they dont hurt your low end power to increase the top end.

Im pretty sure if you really try on your exhaust ports you can get the bend to be 95%+ the size of the stock valve, and at that point you will be ready to worry about larger exhaust valves. I got really stressed porting my heads and I decided I wasnt going to stress myself out more by trying to absulutly trick out the exhaust ports.

I think I got my ports to be about 80-85% the size of the exhaust valve around the neck and that was the best I could do and still be reasonable.

[c2xejk]

Quote:

Originally Posted by Ondonti I know the exit of the port is too big, but the rest of the port is about 66% of the size of the exhaust valves. You could probably install a exhaust valve that was 3mm smaller and the port flow would not change. Exhaust ports make the most power when they are 95-100% the size of the exhaust valve. (this of course is not counting the neckdown around the valve). I stick with what graham says on that. He is not a flowbench guy, but a man who does back to back dyno work and has ported countless heads. The intake.....I agree the ports are too big for the stock valves and cant really be ported to make much of a gain.

Does that mean you are going to do a bunch of engine test? I have said it before, a flow bench does not work very well to design an exhaust port. That doesn't mean that you throw all flow theory out the window....

I have yet to find a top end porter that says that the exhaust port should be the size all the way through. Most talk about the port exit being 80-100% the valve size. With turbo engines you go a little bigger.

The shape of the port is where the magic is!

Quote:

Originally Posted by Ondonti Also, the idea that an exhaust valve must be quite large is an Idea I do not agree with, even when it comes to turbo cars. In theory it might sound good, and it might work great on the flowbench. Exhaust reversion problems should not have to be fixed by handicapping your intake valves, but should be fixed by improving the exhaust port, the exhaust manifold, and getting a turbo that doesnt create massive backpressure. Larger Intake valves bring extra power and unlike just about any other mod in existence, they dont hurt your low end power to increase the top end.

This is a complete misrepresentation of what I have said... First, there must be proper balance within an engine to get good performance. On a normally aspirated car, exhaust valves at 80% intake valve has been proven time and again to be the proper balancing point (give or take a little.) On forced induction engines you are able to stuff a LOT more air through the intake valve. Thus the balance must be adjusted.

Those that have done far more testing (on engine!) than I, have found that upping the exhaust valve to 90% of intake works well. As for upping the intake valve, that's fine, but some the balance should be maintained. Again, this is not what a flowbench says, this is what real world engines are telling people!

Second, reversion is not solely fixed with a bigger valve. The true fix is port shape. Nozzle theory is very important here. A good exhaust port should be shaped somewhat like the cone on a rocket engine...

Third, flow within any port is not 100% uniform. General concensus is that only about 30% of the port is used. The trick is knowing where the port likes to flow and shaping the port to enhance flow in that area.

Fourth, even on a normally aspirated engine you can have reversion. So choosing a turbo that "doesnt create massive backpressure" will not fix reversion problems! Proper exhaust valve sizing and exhaust port shape is the best fix.

Fifth, to get more air/fuel in, you must get the spent air out... With forced induction, you have help getting air/fuel in, so you must help out the exhaust side more. On a turbo car, improvements to the exhaust side time and again make the biggest gains.

Quote:

Originally Posted by Ondonti Im pretty sure if you really try on your exhaust ports you can get the bend to be 95%+ the size of the stock valve, and at that point you will be ready to worry about larger exhaust valves. I got really stressed porting my heads and I decided I wasnt going to stress myself out more by trying to absulutly trick out the exhaust ports. I think I got my ports to be about 80-85% the size of the exhaust valve around the neck and that was the best I could do and still be reasonable.

For the +1 exhaust valve, I believe 80-85% is ok or maybe a little large for just over the shortside radius. As I said, nozzle theory. The real problem would be if you cut down the shortside radius to get to the 80-85%... My research says that you will lose flow by rolling that shortside radius back. Might pick up a little high lift flow, but that is not as important on an exhaust port...

The problem is the turn becomes too sharp for the air to stick to as velocity increases... If it does not stick to shortside radius, then it is not flowing there. Thus that section of the port goes unused. So porting there hurts flow.

The airflow can go fast or it can turn. It can't do both... The straighter the port, the higher the velocity... Exhaust velocity is very high... And if you don't increase the valve size enough, it will have to be even higher...

[Ondonti]

Quote:

Originally Posted by c2xejk Fourth, even on a normally aspirated engine you can have reversion. So choosing a turbo that "doesnt create massive backpressure" will not fix reversion problems! Proper exhaust valve sizing and exhaust port shape is the best fix. For the +1 exhaust valve, I believe 80-85% is ok or maybe a little large for just over the shortside radius. As I said, nozzle theory. The real problem would be if you cut down the shortside radius to get to the 80-85%... My research says that you will lose flow by rolling that shortside radius back. Might pick up a little high lift flow, but that is not as important on an exhaust port... The problem is the turn becomes too sharp for the air to stick to as velocity increases... If it does not stick to shortside radius, then it is not flowing there. Thus that section of the port goes unused. So porting there hurts flow. The airflow can go fast or it can turn. It can't do both... The straighter the port, the higher the velocity... Exhaust velocity is very high... And if you don't increase the valve size enough, it will have to be even higher...

On your "fourth" comment, you should note that you make the statement that valve size can fix reversion yet both you and I stated that it is not the proper fix. Valve size does not dictate port flow in my opinion.


I ported 80-85% of valve size at the bend based on the stock valve size.

I did turn back the lip of the shortside radius, but I only did so to the extent that I remove the 90 deg angle (and there is one) that forces exhaust to run straight to the roof of the port where exhaust is already flowing. That in my opinion causes a problem, just like an internal wastegate that is poorly designed hampers flow out of the actual turbine.

I talked to you and mike about that radius of the short side being too sharp, so I decided to only radius it so that I never actually created a sharper turn then was already present (and I didnt see it possible to make it "less sharp").

I then spend my time raising the roof of the exhaust port near the valve guide. Im sure you have seen that when you stick your finger into the exhaust port from the combustion chamber, your finger hits the roof in a way that just doesnt feel right. If you stick your finger back towards the venturi created by the valve seat, you see how the port is much more open at that point, but the roof all of a sudden swings 90 deg. I tried my best to create a nice turn that "guided" the exhaust rather the impeded it.

You an see in this picture that I didnt just "lay back" the shortside because I kept in mind what you and mike said about the sharpness of the short side.


In this picture you can see that I removed what I would consider a hump in the roof of the port. Picture isnt great, but I tried to remove all of the roof that in my opinion, actually pushed exhaust gases back down to the floor instead of letting them push around the top of the port.



I cant find a good picture of the stock roof. I know cross sections Frank once had posted showed it.
My finger knew that roof very well and hated it.

[c2xejk]

Quote:

Originally Posted by Ondonti On your "fourth" comment, you should note that you make the statement that valve size can fix reversion yet both you and I stated that it is not the proper fix. Valve size does not dictate port flow in my opinion.

By itself bigger valves won't fix reversion... But as part of a complete system, it can...

Quote:

Originally Posted by Ondonti This is of course all before the valve seats are machined to fit larger valves and then a 5 angle job. I thinking regarding the +3mm exhaust valve, that the cost involved would be very high, to have custom seats installed is VERY expensive at the machine shop. VERY expensive.

I don't yet know what my machinist would charge for larger seats... So were you able to get the +2 intake valves on stock seats?

Quote:

Originally Posted by Ondonti I also dont think there is enough room to reasonably fit a +3 exhaust valve in the combustion chamber when you have a stock size bore. With my oversize pistons I have an extra .05" bore on each side of the cylinder, and that gives me a little more room for the exhaust valve, but +3 would put the valve nearly into the actual cylinder wall. That would mean ZERO flow on the the short side, and realistically, a good semihemi pot should flow 20-35% of its gases on the short side of the port. This would put all the flow into the Roof which is already Crap to begin with. With a large overbore like mine I think you can deshroud the exhaust valve enough to make a +3mm valve happy but not with a stock bore. I still dont see how a +3 valve would help reversion though.

Have to see... As I have mentioned before, I am porting my heads very different than you are. My current opinion is +3 exhaust valves will make porting easier...

Quote:

Originally Posted by Ondonti I think reversion is something that mostly should be fixed with valve timing (aka your cam) and of course a good port.

Correct me if I am wrong but I thought you were going to a cam with more overlap...

[Ondonti]

My cam was ground to be turbo happy (low overlap). It would have had Terrible overlap if I had not made sure of that.

There is also the idea of opening the exhaust valve earlier and not actually increasing overlap. Thats why DOHC motors are so awesome with cam gears. My personal problem with opening the exhaust valve earlier in a turbo motor is that turbo motors dont really have very high peak compression levels, but they have very strong latent compression levels (aka 3-4x more cylinder pressure after the piston has moved away from TDC) and while an n/a motor doesnt have much "pep" wasted by opening the exhaust valve early, i would think opening the valve early on a turbo motor would waste a lot of potencial crank turning energy.

Im pretty sure what you mean about the larger Seat is that would make the angle which the port turns much less severe and you could actually get some decent port work done on the floor.

We have not machined the seats yet but my machinist seems to feel confident they will fit. I asked about going much larger long ago and he said the costs of reseating is very high. partially because you arent just putting in a new stock seat, but you have to source, and fit a larger seat.

[c2xejk]

Quote:

Originally Posted by Ondonti My cam was ground to be turbo happy (low overlap). It would have had Terrible overlap if I had not made sure of that.

Good to hear!

Quote:

Originally Posted by Ondonti There is also the idea of opening the exhaust valve earlier and not actually increasing overlap. Thats why DOHC motors are so awesome with cam gears.

Yup, you can independently adjust the intake and exhaust....

Quote:

Originally Posted by Ondonti Im pretty sure what you mean about the larger Seat is that would make the angle which the port turns much less severe and you could actually get some decent port work done on the floor.

Both sides....

Quote:

Originally Posted by Ondonti We have not machined the seats yet but my machinist seems to feel confident they will fit. I asked about going much larger long ago and he said the costs of reseating is very high. partially because you arent just putting in a new stock seat, but you have to source, and fit a larger seat.

+2/+1 is one of the options I am considering for stage 2 normally aspirated ported heads... So it would be nice to not need new seats... though it might be worth it.

[irocelectric93]

So has anyone thought about doing a STS turbo setup? If you dont know what that is...remote setups. Behind the cat in other words. Its pretty clean i dunno. Ststurbo.com apparently they are working on universal kits.....not saying thats the way i want to go but just wondering.

[Ondonti]

StS is located 10 minutes from my house. Their cars are SLOW.

I raped their 4 runner in my n/a 3.0.

[irocelectric93]

I see. Well i dont know how big of turbos they run....and it doesnt seem to me like they do other mods.

[3rdGen3.0]

Quote:

Originally Posted by irocelectric93 So has anyone thought about doing a STS turbo setup? If you dont know what that is...remote setups. Behind the cat in other words. Its pretty clean i dunno. Ststurbo.com apparently they are working on universal kits.....not saying thats the way i want to go but just wondering.

It would suck to hit a puddle after a hard run

[dustbuster]

So, back on topic then....
I've read somewhere, I think it was Ondonti that said a t3/t4 with .57 trim would suck, and .50 would be the best. If I'm understanding correctly, is it because a .57 would take longer to spool but would have nearly the same top end as a .50?
I was thinking of getting a .57 because the chinese ones are cheap and plentiful on ebay, and if my assumptions are correct, wouldn't a .57 be easier to launch?