[KSM-Vtec]

Man i dont believe this....CONGRATS BRO!!!!!

[Shan2nu]

Congrats dude but im having trouble figuring out your ITB setup.

Where exactly is the source of the intake?

Shan2nu

[pranavt]

@nitrous, Kaushik, Mpower: Thanks!

Originally Posted by Shan2nu

Congrats dude but im having trouble figuring out your ITB setup.

Where exactly is the source of the intake?

Shan2nu

Thank you. The intake is behind all those pipes, right in front of the firewall. The area looks way too busy to figure out what is where unless you've seen everything from the beginning. Will be cleaning everything up soon.

[ssjr0498]

thanks for the video link..

Shrey

[Mpower]

Originally Posted by pranavt

Refer to the final pic. There are rubber pipes going from the throttles into a "vacuum log" which is then connected to the FPR, brake booster and charcoal canister. Runner length from the flange to the throttle bodies is around 216mm.

Sweet, I'm not able to see the plenum or the intake pipe in your picture.

IIRC the CBR954 uses an airbox and not a plenum. Whats the dia of the CBR's TBs and how does it compare to the stock ones.

[ported_head]

DIY projects are always super! Congrats on taking up something like this.

The biggest problem as I see it is the location of the fuel injectors. The angle and nature of spray is important to the quality of combustion. In the stock motorcycle ITBs, the injectors spray at the back of the valve. Also, often individual ports are not circular, but oval. So type of injector spray would be important, I think. Does the 954 use dual-stage injection? In your current setup, it would be difficult to achieve accurate tuning or reasonably steady state conditions. The fuel mixtures would vary considerably from one cycle to another, since the injectors look like they are spraying directly at the manifold walls. It would only get worse at higher rpms.

Why don't you change the location of the fuel rail to bring it closer to the ports? Though when I tried to make my own manifold, I had maximum trouble trying to get the injector angle accurate. You will probably have to drill some eccentric holes and make tapered bungs. But you seem to have access to some good labour and machinery so shouldn't be too tough. I was in a mess because I had to rely on an out of centre radial drill and a hand drill.

Also, why are the manifolds welded midway?

[nitrous]

What air filters are you going to use?

[Mpower]

Good observation Ported. I missed it completely. Although I think the low rpms will be the issue. if its a sequential system you might even end up running lean.

The CBR probably has a runner length of 30 mm thats why they put the injector right there.

Originally Posted by ported_head

Why don't you change the location of the fuel rail to bring it closer to the ports? Though when I tried to make my own manifold, I had maximum trouble trying to get the injector angle accurate. You will probably have to drill some eccentric holes and make tapered bungs. But you seem to have access to some good labour and machinery so shouldn't be too tough. I was in a mess because I had to rely on an out of centre radial drill and a hand drill

Easier option if the take the stock mani and slice it just upstream of the injector bungs and build your runners from there. That way you retain the stock flange and injector location.

[ported_head]

Originally Posted by Mpower

Good observation Ported. I missed it completely. Although I think the low rpms will be the issue. if its a sequential system you might even end up running lean.

Crome provides for sequential injection, I think. Because Nitroxx's city was also running Crome. My concern at higher rpms is that volumetric efficiency maybe affected quite a bit. Also, the ITBs on the motorcycle are matched for certain gas flow velocity through the ports, right? I don't know how that works in reference to this setup. I know that the 600RR ITBs have a 2-3 degree taper over their length. And the port geometries are pretty complex.

Originally Posted by Mpower

The CBR probably has a runner length of 30 mm thats why they put the injector right there.

In the 600RR, the distance from the back of the valve to the point of attachment of ITBs was about 2.5 inches (sloppy measuring though). The injectors are aimed to spray directly at the back of the valve.

Originally Posted by Mpower

Easier option if the take the stock mani and slice it just upstream of the injector bungs and build your runners from there. That way you retain the stock flange and injector location.

Our problem was that we were trying to make an intake for the 600RR engine, so no mani to sacrifice. Everything else came out rather nice, except the injector bungs. Actually, that bit is still unfinished. Need to finish it some day.

[pranavt]

Originally Posted by Mpower

Sweet, I'm not able to see the plenum or the intake pipe in your picture.

IIRC the CBR954 uses an airbox and not a plenum. Whats the dia of the CBR's TBs and how does it compare to the stock ones.

There is no plenum, nor am I planning to put one. Velocity stacks and 4 air filters will complete the setup. The TBs are 42mm at the butterfly. They taper from 45mm to 41mm ID.

Originally Posted by ported_head

DIY projects are always super! Congrats on taking up something like this.

Thank you!

The biggest problem as I see it is the location of the fuel injectors. The angle and nature of spray is important to the quality of combustion. In the stock motorcycle ITBs, the injectors spray at the back of the valve. Also, often individual ports are not circular, but oval. So type of injector spray would be important, I think.

Unlike the usual 4 hole injectors, these are 12 hole injectors. Therefore, the drops of fuel are smaller than what you have with the usual injectors. This means that the fuel atomises better even at lower air velocities. The ports are circular btw, and the 42mm ports can make a maximum of around 50-55 bhp per cylinder.

Does the 954 use dual-stage injection? In your current setup, it would be difficult to achieve accurate tuning or reasonably steady state conditions. The fuel mixtures would vary considerably from one cycle to another, since the injectors look like they are spraying directly at the manifold walls. It would only get worse at higher rpms.

The 954 has single-stage injection. I cannot say this from experience, but I do not believe the injector locations to be a problem. People have done it successfully and made daily-driven racecars making around 180-220whp (cams included) with exactly the same setup.

Why don't you change the location of the fuel rail to bring it closer to the ports?

This setup is the first step and by no means the final version. The next version is going to incorporate a few more fun things

Though when I tried to make my own manifold, I had maximum trouble trying to get the injector angle accurate. You will probably have to drill some eccentric holes and make tapered bungs.

Already planned on how do that in the next version, though a little differently.

But you seem to have access to some good labour and machinery so shouldn't be too tough.

Machinery, perhaps. Just the standard CNC machine, a computer, a pair of hands and a few tools. Labour? Let's just say there have been times when I've felt like kidnapping the labourers' kids to make them work. The project was to be finished on the 20th of last month, as a few people know already. The festivities and laziness pushed it much farther. And I'm only talking about stuff like welding, drilling holes or procuring raw material which either required a machine which I didn't have or some special skill. Everything that didn't need a machine was done by me; removing the manifold, measuring, cutting, putting together certain equipment, procuring equipment from customs, drawing the stuff on the computer, etc.

Also, why are the manifolds welded midway?

The manifold is in 3 parts. The flange is a 1:1 copy of the stock D16y7 intake manifold flange that the OHC has. The second/middle step are 4 "adapter" pieces which convert the D-shaped intake ports into circular ports which can then be mated to the ITBs. However, the distance between the intake ports on the flange and each throttle body is not the same. Hence the need to taper the pipes at a specific degree to meet the ITBs at a perfect angle.

Originally Posted by Mpower

Good observation Ported. I missed it completely. Although I think the low rpms will be the issue. if its a sequential system you might even end up running lean.

The ECU is a Honda OEM, so it's batch injection.

Easier option if the take the stock mani and slice it just upstream of the injector bungs and build your runners from there. That way you retain the stock flange and injector location.

That was another option. However, sacrificing the stock manifold was not possible, neither was buying another one.

Originally Posted by nitrous

What air filters are you going to use?

Pipercross bike filters, 4 of them.

Originally Posted by ported_head

Crome provides for sequential injection, I think. Because Nitroxx's city was also running Crome.

Crome doesn't. Neither does any other offering for OBD1 Honda ECUs as far as I know. Doesn't it depend on the ECU though?

My concern at higher rpms is that volumetric efficiency maybe affected quite a bit.

Like I said above, the 42mm ITBs can make upto 55bhp per cylinder. That's pretty much the limit on an N/A D15 engine anyways.

I know that the 600RR ITBs have a 2-3 degree taper over their length. And the port geometries are pretty complex.

So do these. They taper from 45mm to 41mm.

Do you think that because the motorcycles run a fixed length intake, they compensate using injectors with different spray patterns?

Barring a few OBD1 Hondas with variable length intake, how is this different from motorcycles?

In the 600RR, the distance from the back of the valve to the point of attachment of ITBs was about 2.5 inches (sloppy measuring though). The injectors are aimed to spray directly at the back of the valve.

The distance between the valve head to various things like injectors, butterfly, velocity stacks determine the optimum powerband, which I guess you already know. However, mounting them ITBs directly to the engine, or that close to the engine would mean that the engine would have to run at insane RPMs to make all that power. And we're talking about a D15 engine which would pretty much run out of breath at around 8.5k, valvetrain upgrades included.


Apologies if I've missed any questions.

[Sunilb]

Congratulations!!
You finally did what you said...I still remember the day sometime in May-June when you had revealed this idea to me and I was like...what's ITBs..LOL!!!
Salute your determination and all the best for the final setup stage.

[Shan2nu]

Wait a sec, 55bhp per cylinder from a NA 1.5 ltr engine? Thats like 220bhp (146bhp/ltr).

Can you give us some links of such setups?

Shan2nu

[pranavt]

Originally Posted by Shan2nu

Wait a sec, 55bhp per cylinder from a NA 1.5 ltr engine? Thats like 220bhp (146bhp/ltr).

Can you give us some links of such setups?

Shan2nu

No, I meant the 42mm ports of the ITBs. Mated to an engine capable enough, the flow from the 42mm ports would be a bottleneck after the engine started making around 220bhp.

[s0uljah]

Cannot believe I missed this thread.

Love your drive to drive & its nice to see another crazy scientist type affair on the boards after a long time..

[Shan2nu]

No, I meant the 42mm ports of the ITBs. Mated to an engine capable enough, the flow from the 42mm ports would be a bottleneck after the engine started making around 220bhp.

Oh ok. So what is the expected output of your engine gonna be like? It would be nice to see a dyno graph once the mods are done.

Shan2nu