FV Manifold Rulings: Don't buy new until 2011

[dc]

From January 2010 Fastrack—I think this is mostly what was expected for this year, but in case you weren't aware...

FV: Intake manifold rules will remain the same for 2010 as they were for 2009 as approved by the BoD and published in April 2009 Fastrack. (Section 9.1.1.C.5.D.20 of the updated GCR).

An FV ad hoc committee is preparing proposals for presentation to the Formula and Sports Racing Advisory Committee. Their recommendations to the CRB will be published in a future Fastrack for comment by the FV community to determine the final 2011 manifold rules. Those recommendations may take the form of additional measurements to be employed in determining compliance of FV manifolds or the institution of a spec manifold.

This advisory is to inform the FV community that there will be changes in the rules for 2011; this information should be taken into account by competitors in 2010 with regard to existing manifolds and any purchases of new manifolds.

[rickjohnson356]

perhaps this warning will cause some competitors to convert their cars to FST specs?

Obviously not the National racers, since FST is a regional class only.

Maybe not, also, since the impending (unknown) FV manifold changes won't affect regional FV racers as much as it would national racers...

[dc]

All it means is that they are taking a survey of existing manifold dimensions, and working on a standard measurement and means of measuring the manifolds to keep the current crop of "snake eating a cat" tube stretchers from going any further. There is also a chance that a spec manifold will be developed, similar to what has already been done in Australia. I believe the spec manifold would outperform every $1300 manifold on the market, and have a target price range of less than 1/4 of the existing VW manies.

I don't see this as a means for jumping from one class to another, but a way to keep the existing vague rules from making the manifold wars worse than they already are. Lots of people complaining about $1300 manifolds, but I still haven't found anyone who felt they need a new one every season just to compete.

[budawe]

I understand that the spec manifold will use a restrictor plate to duplicate, as close as possible, the existing manifolds. What the class does NOT need is a reason for everyone to buy a manifold. Some think a spec manifold should be mandatory, I do not agree.

[Matt King]

I for one would like to be able to buy an "alternate" manifold equal to the current top intakes for a fraction of the cost. I can understand those who have the best already not wanting to buy another, even if it's only $300-400, but having the option to upgrade to equal performance for much less money seems like a no-brainer. It doesn't even affect the guys who don't care to upgrade, since they could keep what they have too.

[eospeed]

I understand that the spec manifold will use a restrictor plate to duplicate, as close as possible, the existing manifolds. What the class does NOT need is a reason for everyone to buy a manifold. Some think a spec manifold should be mandatory, I do not agree.

I dont think there is going to be a restrictor that would be a mess. There is no need for it.

[sracing]

Eric,

Curious as to why you think a restrictor would be a "mess" ?

Jim

[eospeed]

Eric,

Curious as to why you think a restrictor would be a "mess" ?

Jim

I think it would cause problems because for one. No one will have a real baseline on what to restrict it too.How do we know the builders will use there best motor? Also most of the current cyl heads are not ported to work well with a restrictor plate.So some of us will be making new heads .Who's motor will be used as an example?If a new spec intake makes 1 more HP than the best we have seen then so be it. Everyone is going to have to have one so why not make it better? Our run groups just keep getting worse we may as well have a little more go power. To restrict us and slow us down will only make running with f500 and ff more difficult.Not to mention it is one more part and more weight up high in my car that I dont want and dont need.

E

[budawe]

I ditto everything that Eric says.

[problemchild]

I would agree with Erik too.

We found in FST that the chosen restricter plate took a specific hp away from each engine, but did absolutely nothing to equalize them. It was still an effective tool to keep rpm down and worthwhile since introduced on day 1. In order to have any significant equalizing potential it needs to really be choking down the engine. Hopefully, we can all agree that FVs do not to be significantly slowed down.

With the FST engines, if two engines were 2 hp different, putting in a restricter plate that choked it down 2 mm, would result in both the engines having slightly less power but still being virtually 2 hp different.

IMO, FV needs "virtually" spec manifolds .... one way or another. I would prefer that the intake manifold specs are so defined that no creativity, technology, or rule-stretching will make a difference. Hopefully, the SCCA people can determine these specs and keep 95% of the current manifolds as functioning competitive units.

Cheers!

[sracing]

While I agree with Eric, regarding not wanting to decrease the HP (or top RPM) of A Vee,
Greg's post is terribly incorrect. We have done lots of flow bench and dyno tests.
If the disparity of HP between 2 engines is due to the flow (carb or intake and heads to a lessor degree) there is an ABSOLUTE tendancy to level the performance of those engines. Anyone who says different is smoking something...

If it is due to internal engine mass, CR, something else, obviously a restrictor would do little.

As you point out it also does an excellent job at limiting top RPM (and thus HP) via increased pumping losses. This was its primary intent. (to save engines)

My interest in Erics post was only to see what he felt was a "mess". Most of his points were valid. (Given a manifold that flows at currrent FV flows or slightly more.) Any significant reduction would slow a Vee and that would not be desired.

In regards to head changes, decreased flow makes no difference in optimizing performance. About the only change that would help is possibly more retard in cam timing.

Jim

[Bruce]

I would have to agree with Greg since the only constant in a Vee engine would be the restrictor plate and that does not have magical powers to make every engine HP RATING to be equal. The plate restricts flow rate, not flow.

[problemchild]

Bruce,

The good news is that the top FV engine builders are all very sharp and experienced. They will not give a rat's ass about either Jim or my opinions and will determine very quickly whether to pursue restrictor plates in the context of FV.

Cheers!

[sracing]

I guess you didn't read my post well. I also don't think a restrictor plate that reduces flow below that of a current Vee manifold is a good idea. I wouldn't even consider it.

It also is not going to be totally up to us engine builders as to whether a restrictor plate is used or not. My input would be no, as I suspect the other engines builders would be. However, the CRB supposedly decides based upon membership input.

Again,my question to Erik was only in regards to what was considered a "mess" with restrictors. Having delt with restrictor plate motors, flowing and dyno testing literally dozens of FST, through NASA V8's, we have quite a bit of experience with them.

In particular applications they are very usefull.

[Bruce Livermore]

I thought I might try to clarify a few things regarding the consideration of a restrictor plate in FV.

1. The FV committee would not recommend a restrictor plate be used on existing manifolds. The FV Committee has no intention to reduce the performance of FV.

2. A restrictor plate might be recommended for use WITH a spec. manifold for one or more of the following reasons:

A. To reduce the performance of the spec. manifold to keep it as equal as possible to the best current manifolds.

B. To provide a secondary method of controlling the performance of a spec. manifold to keep them as "equal" as possible. That is, to alleviate concerns that spec. manifolds might not all be "equal" enough.

C. Specifically, to reduce the performance of a manifold modeled after the Aussi spec. manifold which was intentionally designed to flow approximately 15% more than the best (then current - 2004) VW based manifolds.

D. Assuming a spec. manifold similar to that described in C above, to allow a low cost option for increased FV performance in the future (if so desired by the FV community) by simply increasing the restrictor diameter or eliminating the restrictor altogether.

my $.02

Bruce

[smsazzy]

I thought I might try to clarify a few things regarding the consideration of a restrictor plate in FV.

1. The FV committee would not recommend a restrictor plate be used on existing manifolds. The FV Committee has no intention to reduce the performance of FV.

2. A restrictor plate might be recommended for use WITH a spec. manifold for one or more of the following reasons:

A. To reduce the performance of the spec. manifold to keep it as equal as possible to the best current manifolds.

B. To provide a secondary method of controlling the performance of a spec. manifold to keep them as "equal" as possible. That is, to alleviate concerns that spec. manifolds might not all be "equal" enough.

C. Specifically, to reduce the performance of a manifold modeled after the Aussi spec. manifold which was intentionally designed to flow approximately 15% more than the best (then current - 2004) VW based manifolds.

D. Assuming a spec. manifold similar to that described in C above, to allow a low cost option for increased FV performance in the future (if so desired by the FV community) by simply increasing the restrictor diameter or eliminating the restrictor altogether.

my $.02

Bruce

This was exactly what I was proposing at the runoffs meeting. I think you just make the manifold larger and flow more, then restrict it with a restrictor plate. That also minimizes the wory that someone went in and acid etched their spec manifold, etc.