Turbo...Question about the rules

[rjb2968]

Good day All,
I was reading through the 16 rules and stumbled across the compressor section and have a couple questions I was hoping that someone can answer. The first one being the placement of all the components, I have seen the picture but want to make sure I get this right....

1) Restrictor
2)Turbo
3)Throttle body
4)Optional intercooler
5)Charge pipe to engine

The second question I have is about this rule IC 1.7.4

"Plenums anywhere upstream of the throttle body are prohibited. For the purpose of definition, a “plenum” is any tank or volume that is a significant enlargement of the normal intake runner system. Teams are encouraged to submit their designs to the Rules Committee for review prior to competition if the legality of their proposed system is in doubt"

I am wondering how on earth is someone supposed to turbo a 4 cylinder engine? There has to be some sort of log plenum that is MPFI style that has one inlet so that the charge pipe connects to.... Or are you supposed to create an "Intake header" type manifold.

Anyways I was hoping that someone could answer these questions with picture examples or something very clear so I can wrap my head around this.


Thank you for your time.

[Jay Lawrence]

When I was involved, you had to have the restrictor and throttle body before the turbo, which created issues (such as sucking oil through the turbo into the intake off-throttle). I believe this is changed now, as per your 1-5.

For the second question: yes, you pretty much have to have some kind of plenum with a charge pipe connected. So the order is something like: Air filter - Restrictor - Turbo - Throttle Body - Intercooler (in reality only optional if you're running E85) - Charge pipe - Plenum - Head. As for fuelling, there's nothing wrong with keeping the factory bike injector location, but if you're running E85 you could think about a secondary spray injector in the plenum.

As always, if you want to be properly sure, write to the rules committee

[Claude Rouelle]

And who are you? Simple courtesy to introduce yourself? Not necessary?

[rjb2968]

Sorry Mr.Roulle while I do greatly respect your work and all you have done for the racing community I do not feel comfortable revealing my identity. The reason being is that with facebook these days anyone will be able to find me instantly.

Jay, thanks for answering that.... So there pretty much HAS to be a plenum as I thought... that rule is really bothering me. I cant understand what it means in terms of 4 cylinders.

Thanks again

[Claude Rouelle]

So ?

Anyone can find me easily too.... How can you have an opinion or a question and not the guts to present and/or defend it? You would, I imagine, introduce yourself in a public face to face meeting, no? What is the difference on the internet? What do you have to hide or protect that is so important?

[Menisk]

Why the hell should you care who he is? If he has an interesting question and you feel you can contribute to his learning, then help. If not, bugger off. Way too many of your posts to this forum are you bullying newcomers to tell you who they are. Do you have a post count where you deem it acceptable for someone to stop introducing themselves? Do you feel like knowing who he is and where he comes from is going to change the course of this discussion for the better? Do you know or care who I am without going back through my post history to connect the dots. Leave him alone and work by the rule of, "If you don't have anything nice to say, don't say anything at all."

This is not a written rule of this forum and you and Pat Clarke need to stop trying to enforce it like it is.

[Menisk]

In response to your question rjb2968, they're trying to avoid a situation where people make a massive chamber they can boost up before the throttle to essentially have a boost reserve.

You can have as much plenum as you like after the throttle and this rule shouldn't make designing a turbo 4-cylinder any trouble. I think you're getting caught up on the placement of the stock throttles on the bike. You're only meant to run a single throttle on these cars rather than the ITBs the manufacturer runs on the bike.

I think the better question for you at the moment is why you're choosing to run a turbo. My team has a car with a 60% rear weight bias (very uncommon in this competition) that puts power down far better than the vast majority of cars and our N/A 4 cylinder still has too much power. Maybe you're chasing efficiency gains, maybe you're just doing it because it's an interesting thing to learn about (perfectly good reason). Just make sure you have a good think about whether you want the added complication and headaches as well as how you intend to justify your decision come the design event.

[Bemo]

While I don't care that much as Claude and Pat about people introducing themselves, I'll never understand what the big deal is introducing yourself. What are you afraid of when people know you're asking questions about a turbo?

But to come back to topic. Regarding the plenum the keyword is "upstream of the trottle body". The rule doesn't say anything about plenums downstream of the throttle body, which means you can build an as large plenum as you want. Of course this means, you can't use the original throttle body, but with an N/A 4 cyl. this would be the case, too.

[rjb2968]

Ok sorry I'll introduce my self, I did not realize that with people with such caliber as Mr.Rouelle who has dedicated his life to the online cyberbullying of college students who wish to remain anonymous. Perhaps if I buy optimumassmatics you will respect me more.

Hi my name is Bill Cosby and I am from 1985.

The reason we are looking at using a turbo is because we want to focus on making low end torque over large power and we also believe that the efficiency gained will also help us perform better in fuel. Thanks for answering that Menisk and having my back in the battle field over there, you did answer my question I seemed to have completely read over the "Upstream" portion.

-Bill

[woodmandan2]

You could have picked a less controversial public figure to impersonate...