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Discussion Starter · #1 ·
How about we use 40mm Restrictors and limit boost via some sort of pressure release valve rather than go to 34mm Restrictors for both PTG and Open?

The advatage here is it will not force the compete redesign of the cars to make them into very expinsive tourque monsters thus keeping cost down.

No need to go supper storng gear boxes, nutty pistons etc, a stockish motor should still produce a very usable powerband and thus be cheaper.

I throw this out to the readers, I am in a N/A class so really do not care that much but thought this might be of intrest. A blowoff valve should be simple to test and enforce, even esier than opening up the intake to look at ristrictor.

Derek
 

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straight at T
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>How about we use 40mm Restrictors and limit boost via some
>sort of pressure release valve rather than go to 34mm
>Restrictors for both PTG and Open?
>
>The advatage here is it will not force the compete redesign
>of the cars to make them into very expinsive tourque
>monsters thus keeping cost down.

The disadvantage is that pressure release valves are much more difficult to calibrate/police than restrictors. A given valve can operate differently on different cars since careful design of the induction system can affect when the valve will trip. Look at the history of Indy Car (now CART) racing for the issues with using pressure release valves to limit boost.

There were examples where a sufficiently large turbo would overpower the valve, allowing the pressure to continue to rise even though the valve was wide open. I believe that CART (probably the only mainstream racing series to use pressure release valves to control horsepower) owns the valves and issues them randomly to entrants at the events. There are still the occasional complaints that a particular valve opens a bit early (nobody would complain if it opened late ;-)). On a rally car you likely wouldn't notice the sort of differences they complain about, but you would still likely have to have the sanctioning body own/control the valves to ensure that they are all identical - this still doesn't solve the induction design issues. CART covered that with, I believe, minimum manifold reservoir sizes and maximum turbo sizes.

Adrian
 

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>How about we use 40mm Restrictors and limit boost via some
>sort of pressure release valve rather than go to 34mm
>Restrictors for both PTG and Open?
>
>The advatage here is it will not force the compete redesign
>of the cars to make them into very expinsive tourque
>monsters thus keeping cost down.
>
>No need to go supper storng gear boxes, nutty pistons etc, a
>stockish motor should still produce a very usable powerband
>and thus be cheaper.
>
>I throw this out to the readers, I am in a N/A class so
>really do not care that much but thought this might be of
>intrest. A blowoff valve should be simple to test and
>enforce, even esier than opening up the intake to look at
>ristrictor.
>
>Derek

This is essentially what they do/did to police boost levels in CART open wheel racing. The problem that they experienced is that the pressure relief valves (blow-off valves) were designed for static pressure loads and their effectiveness would change according to where they were placed in the manifold relative to the incoming flow of air. A couple of teams were busted for putting a spacer between the valve and the manifold thus reducing the pressure across the face of the valve and giving them more boost to play with. It can be hard to police, it would be good to look at the rules that CART used for this.


Scott
 

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>>How about we use 40mm Restrictors and limit boost via some
>>sort of pressure release valve rather than go to 34mm
>>Restrictors for both PTG and Open?
>>
>>The advatage here is it will not force the compete redesign
>>of the cars to make them into very expinsive tourque
>>monsters thus keeping cost down.
>>
>>No need to go supper storng gear boxes, nutty pistons etc, a
>>stockish motor should still produce a very usable powerband
>>and thus be cheaper.
>>
>>I throw this out to the readers, I am in a N/A class so
>>really do not care that much but thought this might be of
>>intrest. A blowoff valve should be simple to test and
>>enforce, even esier than opening up the intake to look at
>>ristrictor.
>>

Sorry chimed in late.

Scott

>>Derek
>
>This is essentially what they do/did to police boost levels
>in CART open wheel racing. The problem that they
>experienced is that the pressure relief valves (blow-off
>valves) were designed for static pressure loads and their
>effectiveness would change according to where they were
>placed in the manifold relative to the incoming flow of air.
> A couple of teams were busted for putting a spacer between
>the valve and the manifold thus reducing the pressure across
>the face of the valve and giving them more boost to play
>with. It can be hard to police, it would be good to look at
>the rules that CART used for this.
>
>
>Scott
 

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Hows about we all agree that we are going to be ladies and gentleman and not cheat about a boost limit that we set at say......fifteen pounds or so?
Then if/when someone is found to be cheating they don't get to play for a few years as punishment for being naughty.
It is easy enough to see which car has say.....an extra hundred horses.

Hows about some other ideas to go along with our realizing that we are virtually all working stiffs without the really deep pockets to burn huge money at an enjoyable HOBBY forever?

I'm all for anything that we can do to put the FUN back into rally.

Thoughts?
John Lane
Viva Le Pro Le Ralliat
 

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Hmmmmm.....I like the concept, as it saves the $$ cost and the reliability loss associated with the high torque engines.

Instead of a relief valve and the associated problems, how about a boost pressure recording device, consisting of a manifold pressure sensor and a sealed microprocessor device to capture peak boost in an event? Have the sanctioning bodies own some portion of these systems.

It could be designed in a fairly straightforward manner, although it might take some development testing time to insure reliability and see if other compensating HP factors like temp would also need to be recorded. And to have the pressure sensor mounted in a standard location per each engine.

Regards,
Mark B.
 

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>Hmmmmm.....I like the concept, as it saves the $$ cost and
>the reliability loss associated with the high torque
>engines.
>
>Instead of a relief valve and the associated problems, how
>about a boost pressure recording device, consisting of a
>manifold pressure sensor and a sealed microprocessor device
>to capture peak boost in an event? Have the sanctioning
>bodies own some portion of these systems.

That would be interesting, although creative sensor placement may be a problem ;-).

>It could be designed in a fairly straightforward manner,
>although it might take some development testing time to
>insure reliability and see if other compensating HP factors
>like temp would also need to be recorded. And to have the
>pressure sensor mounted in a standard location per each
>engine.

It probably wouldn't be an issue on different instances of the same engine, but different engine/manifold configurations might be difficult to equalize (i.e. the pressure measured at some common point may not be equivalent to the pressure seen at the cylinders). Ultimately, you set yourself (or the sanctioning body) up to do a lot of research that is neatly avoided by using a restrictor. Why do you think the FIA went to restrictors? They are very easy to police and quite difficult to circumvent (Toyota excepted, of course ;-)).

With a boost limit you would probably see large turbos that can flow enough air to make the boost limit at peak RPM - now you start developing the motors to run at higher RPM, rather than developing them to make torque. Since the parts to make torque on a restricted motor are available, and the parts to generate more HP on an unrestricted boost-limited motor aren't, you probably have more scope to spend money developing the latter.


Adrian
 

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??

It never ceases to amaze me what great insight I read on this board when I get the chance. :p

I'd like to make a suggestion - anyone who thinks they know "how to fix Open Class", should go and run the class at a national or east coast club event in a *competitive* Open car, come back and then make suggestions. Before you go in with any preconceived notions on where the bulk of the costs are, I'll give you a hint - engine power is NOT the money pit.

DISCLAIMER: This is nothing personal; it's simply mundane re-reading every expert's opinion on this subject with pretty much nobody knowing what they're talking about.
 

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agreed with Markn

hows about we just dispense with the 34mm rule altogether like we did with the age limit rules

doesn't make sense...get rid of it

john
 

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RE: ??

Excuse us for making a couple of comments on the difficulties of regulating boost. We'll leave this to the "experts" on this form.

Scott


>DISCLAIMER: This is nothing personal; it's simply mundane
>re-reading every expert's opinion on this subject with
>pretty much nobody knowing what they're talking about.
 

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Discussion Starter · #11 ·
I do not just make this stuff up. To come up with this idea I looked at the problem as presented by the PRB - the insurance arm wants us to do something about the speed of the cars. Historicaly that has been done by a restrictor but many people have noted incres in cost to build a optimized 34mm restrictor car.

I did some investigations on that subject by going back to articals in Racecar Enginering from the time FIA moved down to 34mm. A good artical by RallyArt talked about the gearbox, the need for triple plate carbon clutches motor revisions, stronger drivelines etc as a direct result of this rule change, all moves farther from a stock Evo and thus more costly (possiblely not for RallyArt but for a US priveter costly).

So I tried to think of a way to limit power with out using a restictor, I looked at fuel delivery but to problematic and could still produce lots of Low RPM power so I looked again at air. As the mass of the air is decided by the pressur and the volume everyone knows make more pressure if the volume goes down, that is what they do now with 34mm, but if we used a more decent 40mm, so the car can still make decent HP, use gearing to make torque and limited boost to some level so clutch torque is limited. Would this be a cheaper way to make fun but limited open class cars?

Running some numbers using formalas from the Bosch Automotive Handbook, and looking at other articals in the engineering press it looks like it might work for this part of the problem ie making Insurance Happy while not opening a loophole for people to build supper high torque motors to get a round the intent of the rule.

I am not saying 34mm restictor cars will cost soooo much more that those of us who can afford to run them in the whole pro series would even care about the few extra thousands for a good 34mm motor and drivetrain, but the 34mm rule also applies to the club rallys and people who scrape together $40k for an Evo will have problems with 10k more to make it as good as the jones' EVO that did get the optimisation and what does that 10k buy them? A car that could have the same performance numbers for a heck of a lot less money if the rule was written in a diffrent way.

In conclussion: It may be possible to produce the same desired effect of the 34mm rule in another way that cost less and still makes the insurance company happy, as it produces the same effects.
 

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>I do not just make this stuff up. To come up with this idea
>I looked at the problem as presented by the PRB - the
>insurance arm wants us to do something about the speed of
>the cars. Historicaly that has been done by a restrictor but
>many people have noted incres in cost to build a optimized
>34mm restrictor car.
>
The insurance company doesn't really care how fast we go, just how much damage we do. Our overall speeds aren't the problem. A current 40mm car is about as fast as WRC car (in a straight line) and maybe a well built GrA car. It's pretty much been decided that changing to 34mm won't dramatically affect stage times in the US. The REAL reason risk management wants 34mm is conformity. Insurance companies don't like things that are different, or off the standard. The world standard for Open class cars is 34mm, so regardless of speed 40mm is different. Different is bad. Insurance companies don't work on things like logic and reason. Showing them speed tables and testing data of speeds vs. restrictors does nothing. All they care about is what everyone else is doing, cuz that's what they are gonna do. And in the rally world, everyone else is doing 34mm.

Soooo..... Well any ideas of slowing the cars down are always interesting and welcome, we need to realize that slowing the cars down is not the intent of the 34mm restrictor. The intent is to keep the insurance companies happy. Just like cats and no-lead gas keeps the greens happy, noise limits keep the locals happy, etc....Sucks, eh.

Dennis Martin
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920-432-4845
 

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>What about controling the fuel with a lower octane?
>Wouldn't that reduce speed and be somewhat easy to check?
>
You would get a kick out of just how much power I can get out of an optimised turbo thing with 92 octane, programmable fuel infection and attention to detail. We can break anything you like in the drivetrain....No problem. Really big power breaks really expensive junk. I have LOTS of them tee-shirts.

If as that other bloke noted earlier about the insurance companies wanting everybody to be the same (thus: 34mm) then we will all "Get" to do what it takes to make use of 34MM and smile as they do it to us.
I believe that we should all get to be real comfortable with that "Thank you sir....Can I have another." We all know better then to expect the insurance companies to offer us the hug or otherwise to go with.

That other sanctioning body.......NASA? They having the same problem? Hmmmmmmm...........

As long as I can do my Gp5 thing with no restrictor I'm happy. I still beat them four wheel drive guys on the straightaways :p assuming of course I can make it that far.

John Lane
Viva Le Pro Le Ralliat
 

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>As long as I can do my Gp5 thing with no restrictor I'm
>happy.


My G5 car runs with the 40mm restrictor....four of them, but Holley calls them venturis.
 

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Why not just let the engines be open, but mandate a 'spec' clutch that only can handle relativly small amounts of tourque?

That way, someone can spend all the money he/she wants building the 600HP monster Subie engine, and we can all chuckle in amusment as they drop out in the 3rd stage after toasting their clutch!

:+
 

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>My G5 car runs with the 40mm restrictor....four of them, but
>Holley calls them venturis.

Mike.....I believe that the restrictors in your toy are the cylinder heads. Just the way we like 'em. Bet that you have a lot of FUN abusing your noisy toy. That is why I rally. To have maximum fun for my dollars spent with my friends.

What say all of you?

John Lane
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Hows about we figure out how to get our friends in the insurance industry to see that we are in fact just a bunch of hooligans blasting about in the woods safely. How about a maximum number of tires per event? If we can inly have six tires per day then one will have to figure out how to be good to 'em.
I go rallying to see just how stoopid fast I can go on logging roads without fear of jailtime. I don't want to deal with having to slow down. But that is me. I am well known for being a hooligan.

John Lane
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>>As long as I can do my Gp5 thing with no restrictor I'm
>>happy.
>
>
>My G5 car runs with the 40mm restrictor....four of them, but
>Holley calls them venturis.

Gee, am I better off with the four 38mm restrictors in my 45 Webers on my Gp2 Saab?





John Vanlandingham
Seattle, WA. 98168

Vive le Prole-le-ralliat

Black Rocket Rally Tires
http://www.blackrockettires.com/
 
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