Bigger Intake Valves with 1100TB ?

[Andreas]

Hi,

I’ve read that several members here have used the bigger TB’s from the 1100.

Do you just match the intake ports to the bigger diameter or do you also install bigger valves in the head?

I’m considering this mod and I’m unsure what the gain would be, if the stock valves are kept.

Won’t you just increase the intake volume and reduce velocity? Or does the flow into the cylinder really improve?

Best regards
Andreas

[Charlie @ Evergreen]

What is important is how is the engine and turbo system upgraded? If stock or 810 with original (not upgraded turbo) your not gaining much except upper midrange and top end power very minimal. Best bang for buck power gain from stock motor to 810 build is upgrading the turbocharger, exhaust and air filter tune it. You can pull a nice average of 145HP or more depending on boost and fuel with this setup. If you want go farther at that point then add ATP Studs/nuts with 1mm larger exhaust valves. At that point you can then add the 1100s. Do the 1100s last on the upgrade lists. Sure few guys will chime in but don't think really need the 1100s with these upgrades up to 200hp. I was running 1100s with this all done to my 810 but did give up some low end power which most love. This setup gave a good boost / power band from 4000RPM to 10,000

[edinlr]

Great question Andreas. The top engine builders use a ratio of valve area to cylinder bore in the 26 to 28% range. A stock bore is 66mm with an area of 3421 sq/mm. The stock intake valve is 34mm with an area of 907 sq/mm. This ratio works out to 26.5 which is about perfect. I looked at going to 35mm intakes, but that put the ratio at 28.1, which is too much valve, and yes, you can have too big of intake valves. I would not go larger unless you are going to an 810 kit.

[Andreas]

Hi,

thanks for the answers.

I'm doing an 810 build with a GT 2056 Turbo.

1100 TB's are also laying here, but I'm unsure how to make them work well.

I assume if i just hog out the intake parts it'll all match up smoothly, but it'll reduce the velocity in the intake trakt.

At that point I'm unsure if there's an actual performance gain or if bigger inlet valves would be required to actually make this perform well.

[Streetfighterkz]

I assume if i just hog out the intake parts it'll all match up smoothly, but it'll reduce the velocity in the intake tract.

Being forced induction, you won’t really lose velocity. It’s not an N/A engine where the downstroke of the piston pulls the air mixture into the cylinder.

Later, Doug

[Charlie @ Evergreen]

The 1100's pretty much bolt right up. I used 1000J Boots and port matched to the head. They slide right on and the Plenum fits as it did before.
Intake side of the engine breathes good but lacks exhaust flow hence the 1mm larger exhaust valves with header porting/port matched turbo with modified built billet makes big difference in power.

[edinlr]

Andreas, not trying to tell you what to do, but it is very easy to mess these ports up if you don't know what you are doing. The Jap superbikes from this era are known for having ports that are too big. The pros frequently have to add welds or epoxy to get them to perform properly. The second point is do nothing around the valve seat unless you are trained on this. A little material off in the wrong spot there will drop 10 hp in seconds. I will post pictures later, but the guy who does my heads took out a bit of material where the exhaust port exits to the pipe. He also ported the pipe and the spider. I think that may correct the exhaust problems as well as bigger valves could do.

[edinlr]

Here is a view of the exhaust port that has been cleaned up and the ridge removed, the inside look at the pipe, and I think the spider exit shows up too, it has been split, ported and then rewelded.

[edinlr]

Sorry about repeating the pics. Rookie error

[Würstchens-Turbo 810]

Hi,

thanks for the answers.

I'm doing an 810 build with a GT 2056 Turbo.

1100 TB's are also laying here, but I'm unsure how to make them work well.

yes it wil works fine .
i am also use a GT2056 with 1100 TB´s and 350cc Injectors and PC3usb .
I increased the inner diameter of the intake rubbers on both sides, stock valves.

Many years ago I had a cylinder head reworked and installed larger intake valves, which only brought disadvantages, but the rest was still all original

TG
Horst

[DEATH_INC.]

2 of the biggest power gains I had with mine after the 810 and larger turbo was making some 38mm headers, and making a larger (2") transfer pipe and enlarging the opening into the plenum box.