Racer X engine build thread

[lgk]

Originally Posted by subxero

Interesting, is there a way to increase the port size but then pressurize the air or something of that nature? Obviously like you mentioned earlier for fuel, get a fuel pump, but for air?

they make turbos and superchargers to increase pressure and volume, but they cost a lot of money. and you need additional controls to run them.

from what i gather, the velocity is important for several reasons
the carbs need it to atomize fuel well.
it optimizes intake harmonics.
it helps throttle response.

[Racer x]

With nitrous I can add as much hp as needed. And probubly more. With the Wizards of nitrous system I have very consistent performance from the nitrous. Next week I will see how it does. I will be putting 30 hp on a 30 hp motor. The turbo guys got 54hp in indoninesia. I want to beat that.

[subxero]

Originally Posted by lgk

they make turbos and superchargers to increase pressure and volume, but they cost a lot of money. and you need additional controls to run them.

from what i gather, the velocity is important for several reasons
the carbs need it to atomize fuel well.
it optimizes intake harmonics.
it helps throttle response.

Turbo, DAH! Sometimes i am so stupid, i guess when i think motorcycle i just don't think turbo or supercharged.

One would think i would of put two and two together though considering i have a tubrocharged car

Thanks for making me realize why my original post seemed like such a good idea... because it is and someone already figured it out.

[Racer x]

Turbo needs fuel injection. And nitrous does not. But at this stage the clutch is the problem not the power adder

[lgk]

Originally Posted by subxero

Thanks for making me realize why my original post seemed like such a good idea... because it is and someone already figured it out.

it is awesome, but on a bike its a much more challenging install, due to space and control requirements.

[Racer x]

I am thinking about a turbo. Not so much for the boost .But when you try to stuff a lot of nitrous into a little engine it backs up. A turbo would be like a one way valve. always moving the entire mixture in one direction. And because I am using it with nitrous and ethanol with low boost I will not have to use an inter cooler.

I got a little more done on the head. Final shaping and now I just have to work out the little pits and scratches

head polish 001.jpg head polish 002.jpg head polish 003.jpg

[Racer x]

This is the other side of the polished sandwich. The pistons. This is an old piston with a scuff side I was experimenting on. But the idea is to remove all the sharp edges. Anything that can heat up.

Now stay with me.
The pistons have a 12.5 to 1 compression ratio and I removed some of the top. So it is less than 12.5to1. But I don't know how much.

I not only bored the block 4mm to fit the larger pistons I removed .010 from the top of the block. so the compression goes back up.I dont know how much.

But I removed some of the material from the head. SO it goes back down.

I started with 12.5 and I guess I still have 12to1 compression.

Also by removing the top of the block the head comes down.The distance from the crank to the cam is shorter. The slack in the cam chain is taken up by the tensioner, But it rolls the cams in a retarding direction. Opening and closing them later. This is better for top end power. It opens the exhaust valve sooner.

pistons 001.jpg pistons 004.jpg pistons 011.jpg

[tubarney]

Did you just say your camshaft is retarded.

Nice work on the pistons. I thought you needed those groves in the top?

With cylinder heads it is all about the velocity of flow. Not how much or how big

[tubarney]

Wait I shouldn't say how much, because CFM gains are what you are looking for. The bigger you make the ports the slower the speed of the air so your CFM could actually be worse than a set of smaller ports.

[Racer x]

Yes the whole thing is a retarded.
The groves in the top of the piston are for valve clearance. They are still there just all the metal around them is gone and I smoothed out the whole piston.

Yes I only clean up the intake ports. And put that swearl pattern on the walls. The exhaust I will open up to match my header. Stock port is 26mm and I will open it up to about 30

[Racer x]

I have one exhaust port opened up .

The first photo is the stock port. The second is the cleaned up one.

head work 009.jpg head work 010.jpg

[alex.s]

Originally Posted by tubarney

Wait I shouldn't say how much, because CFM gains are what you are looking for. The bigger you make the ports the slower the speed of the air so your CFM could actually be worse than a set of smaller ports.

eric actually has a flowbench built into his eyes!

[Racer x]

In the exhaust port there seems to be a little venture. A small lump designed to pull the air out of the air injection port that comes up out of the valve cover. I remove that. First because I don't have air injection. And because with nitrous I need MAX flow.

For the intake I just do a little clean up. But hog out the exhaust.

[alex.s]

is there any point to having the ex. air injection if you don't care about emission control?

[tubarney]

Originally Posted by alex.s

is there any point to having the ex. air injection if you don't care about emission control?

Don't think so. I wouldn't be there if they didn't but the kleen air system on the bike. Only hurting your flow.

Eric where did you stick that light, I'm having trouble getting photo's of the exhaust ports. Got plenty of the intake.

[Racer x]

The Air injection is for the cataletic converter. I just layed the light on the head.

[tubarney]

Originally Posted by Racer x

The Air injection is for the cataletic converter. I just layed the light on the head.

i get it now. Its called secondary air injection. It's not needed if you don't have a catalytic convertor

[Racer x]

This is the finished head. Now I just have to put it together and adjust the valves

[cuong-nutz]

Looking Good!

Would there be any gains for you if you used the Ninja 500 carbs?

[Racer x]

I don't want to use cv carbs at all. But I don't think the 500 cabs will fit. I think they are too wide.

[tubarney]

What do you use to scrap the carbon off the bowl and pistons? Also, do you just use regular aluminium polish?

How many angles you have cut into your valve seat. Theres 3 for the valve itself, any extra? Dropped my cylinder off today, old mate is going to try a 5 angle seat job. Depends how much room there is.

[Racer x]

I use a Dremel to do the head. The little brushes are great. If I am cleaning old pistons I would use chemicals like acid and a scotch bright.

The head comes with a three angle cut. I have the tools to do four of the six cuts. I just do the mating surface. After that I hand lap the valves and vacuum test each set. After that I will adjust the valve clearance.

[tubarney]

So wait, you don't use any polishing compound along with the dremel on the bowls or pistons?

All this polishing has got me in the mood

[Racer x]

O sorry. I use red rouge and mothers. But only after grinding and sanding.

[bruce71198]

Racer X, When we used to build nitrous car engines I would build the bottom end similar to a super charged engine (lower compression and less cam overlap etc.). You seem to lean toward the higher compression pistons, are you worried at all about the cylinder pressure your going to expierience with the higher levels of nitrous you plan to run?

[Racer x]

Yes. But only about the bolts stretching in the case. I have ARP studs for my other motor. So far I am not having problems. But I go little steps at a time. Nitrous loves compression. As long as you can control detonation or preignition.

This new engine will be down from 12.5 to 12.0 to give a little more room in the chamber.

[bruce71198]

Originally Posted by Racer x

Yes. But only about the bolts stretching in the case. I have ARP studs for my other motor. So far I am not having problems. But I go little steps at a time. Nitrous loves compression. As long as you can control detonation or preignition.

This new engine will be down from 12.5 to 12.0 to give a little more room in the chamber.

The top of the piston was more my concern, looking at that one photo above. Also the violent cylinder pressure spike when you compress nitrous. You'll have to excuse my ramblings, as I have not played with nitrous in years ,but isn't the flat top piston better as far as flame travel and piston loading when running nitrous ?

[Racer x]

Yes a flat piston would be better. And I have flattened the piston as much as possible. But I need 200 psi of compression to get decent power without nitrous.

I also don't want to have custom pistons made at this stage.

Nitrous has come a long way. Wizards of Nitrous has taken nitrous to the next level. Because of the control and consistent performance of the system I can push the motor to its limit. The problems I have had relate to the other guy systems being inconsistent in the mixture.

[tubarney]

wouldn't flattening the piston weaken it structurally? I know you said your nos system is good now, but doesn't it worry you that your piston is not as strong as the engineers designed?

[tubarney]

With the 5 angle seat job. They add another angle before and after the actual valve seat. So your valve still has 3 angles 32, 45, 67.5; they put say a 20 degree angle before and a 75 degree after, basically smoothing out the entrance and exit of the valve. So you have 20,32,45,67.5,75; Your valve touches the three middles one.

If you have the tools to do the cuts yourself I will get back to you with the angles they use on my head.

[mgentz]

Originally Posted by tubarney

With the 5 angle seat job. They add another angle before and after the actual valve seat. So your valve still has 3 angles 32, 45, 67.5; they put say a 20 degree angle before and a 75 degree after, basically smoothing out the entrance and exit of the valve. So you have 20,32,45,67.5,75; Your valve touches the three middles one.

If you have the tools to do the cuts yourself I will get back to you with the angles they use on my head.

I'm fairly certain your valve only touches the 45....

[tubarney]

Originally Posted by mgentz

I'm fairly certain your valve only touches the 45....

So if it only touches the 45 that means the valves don't need re-shaping. Can't believe how I didn't know this. But im still learning and relatively new to working with valves. Makes so much more sense now.

[Racer x]

I ran the first engine on the dyno. I really can't say I am thrilled. I had 34 hp from my other engine and the big bore only went to 32. I did use a different dyno. New and better. But I was hoping for more.
The engine handled a 20 shot of nitrous on over twenty pulls making over 50 hp and still making 31 at the end of the day.
I am going to change back to a 2 into 1 exhaust and see what happens.

[Racer x]

Originally Posted by tubarney

So if it only touches the 45 that means the valves don't need re-shaping. Can't believe how I didn't know this. But im still learning and relatively new to working with valves. Makes so much more sense now.

I just run my cutters along the 45 to make it perfect. Then new valves lap in and seal up nicely.

[cuong-nutz]

Originally Posted by Racer x

I ran the first engine on the dyno. I really can't say I am thrilled. I had 34 hp from my other engine and the big bore only went to 32. I did use a different dyno. New and better. But I was hoping for more.
The engine handled a 20 shot of nitrous on over twenty pulls making over 50 hp and still making 31 at the end of the day.
I am going to change back to a 2 into 1 exhaust and see what happens.

Interesting, I would have expected better numbers.

[Racer x]

The engine was only down 2 or 3 but I was hoping to get close to 40 with a 12.5 to 1 big bore. I was very happy with the 16 ft lb of torque. I am going to go through the engine and change the exhaust.

The nitrous was perfect. It was jetted for 20 hp and it did just that.

[lgk]

what fuel did you use for the dyno run?

[Racer x]

Mostly rocket 110 but it was cut with 115 so that is not a great thing. The initial runs used 110.

[tubarney]

How much does this nitrous cost you? 20 pulls!

[Racer x]

Nitrous is five dollars a pound. I usen about 10 lb maybe during the day. But once it is tuned. A twenty lb bottle last all season.

If you factor in nitrous 1 lb. And race gas at 10 dollars a gallon. Plus two spark plugs . Each run at the track cost about 25 dollars.