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Last Post 11 Jul 2011 07:20 AM by  DrJones_CMR
BSP: You are not welcome in FP
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ratt_finkel
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21 Apr 2011 10:37 AM

    That's the message I received at the Houston National Tour.

    For those not in the know, Prepared is a unique ruleset. And unfortunately does not make a smooth transition for lower prepared cars. Make sure you are compliant! Even if your turbo inlet is smaller than the required restrictor! And last but not least, don't beat the "true" FP cars while you are there.

    SmokingTires
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    21 Apr 2011 11:24 AM
    ratt_finkel wrote:

    That's the message I received at the Houston National Tour.

    For those not in the know, Prepared is a unique ruleset. And unfortunately does not make a smooth transition for lower prepared cars. Make sure you are compliant! Even if your turbo inlet is smaller than the required restrictor! And last but not least, don't beat the "true" FP cars while you are there.

    Yup, sorry Jeremy. Stand alone rule set. Great driving at the event though. I'm living with the restrictor being larger than my turbo inlet also. But the rules say .500" of 52mm. That's the kicker. Otherwise I wouldn't have spent a bunch of money making mine :(

    Quote:

    17.1 AUTHORIZED MODIFICATIONS

    The modifications defined in the Prepared Category Section are the

    only allowed modifications. The rules in this section stand on their own;

    they do not build upon the Stock or Street Prepared Category rules.

    Modifications shall not be made unless specifically authorized herein.

    No permitted component/modification shall additionally perform a prohibited

    function. If the rules do not specifically authorize a modification,

    it is not permitted.

    -Mike "Was lucky enough to not get raw timed by Jeremy on the right course before blowing my car up in Mineral Wells" Brausen

    :)

    DrJones_CMR
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    21 Apr 2011 12:44 PM
    There's a part of me that wants to find a salvage GXP and go to FP.
    That 52mm .500" thing makes it a little more interesting...
    SmokingTires
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    21 Apr 2011 01:26 PM
    DrJones_CMR wrote:
    There's a part of me that wants to find a salvage GXP and go to FP.
    That 52mm .500" thing makes it a little more interesting...

    And in the next year it is going to be a smaller restrictor. Killing any hope of a turbo car getting above 6500rpm with any reasonable power band.

    Aufaber
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    21 Apr 2011 01:57 PM
    SmokingTires wrote:
    DrJones_CMR wrote:
    There's a part of me that wants to find a salvage GXP and go to FP.
    That 52mm .500" thing makes it a little more interesting...

    And in the next year it is going to be a smaller restrictor. Killing any hope of a turbo car getting above 6500rpm with any reasonable power band.

    Well... Our FP car makes in the low to mid 200's peak hp and i'd say it's pretty good for the class. So, "killing any hope of a reasonable power band" sounds a bit like hyperbole.

    SmokingTires
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    21 Apr 2011 02:41 PM
    Aufaber wrote:
    SmokingTires wrote:
    DrJones_CMR wrote:
    There's a part of me that wants to find a salvage GXP and go to FP.
    That 52mm .500" thing makes it a little more interesting...

    And in the next year it is going to be a smaller restrictor. Killing any hope of a turbo car getting above 6500rpm with any reasonable power band.

    Well... Our FP car makes in the low to mid 200's peak hp and i'd say it's pretty good for the class. So, "killing any hope of a reasonable power band" sounds a bit like hyperbole.

    38mm as published, would choke out any top end I have. Right now I rev out to 8k RPM with a aftermarket 4.11 gear to hit 71mph in 2nd. I won't be able to do that at 38mm. In 2nd gear I don't have boost until 4k rpm. So I have from 4k rpm to a weak 6.5k to make any power. It means we need to contact some WRC teams and find out their tricks for building around the restrictor.

    I might have an XP evo next year.

    MrAWD
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    21 Apr 2011 05:37 PM
    Just put two of them parallel to each other!! :)

    Fedja
    EPcivic
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    21 Apr 2011 07:14 PM
    SmokingTires wrote:
    Aufaber wrote:
    SmokingTires wrote:
    DrJones_CMR wrote:
    There's a part of me that wants to find a salvage GXP and go to FP.
    That 52mm .500" thing makes it a little more interesting...

    And in the next year it is going to be a smaller restrictor. Killing any hope of a turbo car getting above 6500rpm with any reasonable power band.

    Well... Our FP car makes in the low to mid 200's peak hp and i'd say it's pretty good for the class. So, "killing any hope of a reasonable power band" sounds a bit like hyperbole.

    38mm as published, would choke out any top end I have. Right now I rev out to 8k RPM with a aftermarket 4.11 gear to hit 71mph in 2nd. I won't be able to do that at 38mm. In 2nd gear I don't have boost until 4k rpm. So I have from 4k rpm to a weak 6.5k to make any power. It means we need to contact some WRC teams and find out their tricks for building around the restrictor.

    I might have an XP evo next year.

    The 38mm proposal is published for member comment, it is not set in stone yet. By everything we can tell, a BSP Evo makes significantly more power than the NA cars in FP can. Adding a 52mm restrictor, which is larger in diameter than the turbo inlet is not likely to result in any significant reduction in power, so the FP Evo is a bit of an outlier right now. 38mm was choosen with the intent of limiting the output of these cars to something closer to the status quo. My opinion is that done correctly, with a 38mm restrictor, the EVO will still have at 50-100hp advantage over the NA cars. If you think it is the wrong number, please write a letter, and support your opinion with some useful data. Unfortunately, there isn't a wealth of information out there regarding restricted turbo power capabiities. You might be supprised how much air can flow through a 38mm converging-diverging nozzle.

    -Chris

    ratt_finkel
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    21 Apr 2011 09:07 PM
    Chris speaks the truth. The 38mm restrictor will do nothing to slow down the EVO's. You will see NO appreciable difference in power levels for a properly built motor. All this does is add additional expense in the Evos attaining those numbers.
    SmokingTires
    Basic Member
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    Posts:263


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    22 Apr 2011 10:00 AM
    50-100hp advantage, with a diminished RPM range, 5"+ in vehicle width, 400lbs higher minimum weight, and trying to tap the rally community for tightly kept information on builds.


    I'm just looking for some type of logical progression. It doesn't make sense to me that FP would require a similar amount of money to build an engine as XP(or more), to make 350-400hp (A Datsun makes what, 240hp at the wheels?).

    I'm not doubting that with the right engine build, the power can be made. I do however believe that you will be hard pressed to find many turbo car owners that will look at spending XP levels of money to develope an engine, to make BSP power ranges. Why wouldn't they just go to XP?

    It's asking the turbo cars to up their investment or get out. And sadly XP looks like the reasonable/cheap/fun option.
    Evo8RA
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    22 Apr 2011 11:03 AM

    Instituting a restrictor size this small - 38mm (1.5") - would certainly have the effect of restricting power, but would have the side-effect of choking off air flow beyond 5500 rpm with dramatic falloff in power beyond that point. As an example, the Evo turbo spools up in 2nd gear at around 4000 rpm, or later if you use a larger turbo. (Please don't reference 3rd/4th gear dyno pulls to say its lower rpm - big difference.)

    I did some research on WRC 34mm turbo restrictors, which I must assume is the reference point, since these motors are restricted to 300hp. What I found was that the useable rpm range on these $100k turbo motors is 4000-6000 rpm. WRC makes this work by using $120k full sequential electro-hydraulic transmissions, not an option for autocross. Looking at a gear ratio calculator, an Evo limited to 4000-6000rpm of useable power would be using 1st through 4th gears in a national-type autocross course to reach 73mph. This amount of shifting would render any car non-competitive against top National cars. Spending several thousand dollars on a re-geared transaxle would adjust this to just barely fit inside the top of 3rd gear. I know from experience, that requiring this much use of 3rd gear requires approximately 7-10 upshift/downshifts to stay in the power, again making it unlikely to ever win against top National competition.

    I am also concerned that focusing on peak power targets may be an over-simplistic approach to justifying addition of more restrictions to turbo cars, when no event results support a restriction. There has yet to be anyone who can win against top National cars, let alone dominate the FP class in a turbo car. Turbo cars have been nothing more than competitive and I feel it is unwarranted to start making them less competitive until there are some national event results to support doing so. Over-restriction will immediately result in an unintended, indirect exclusion of turbo cars from the FP class. I believe turbo spool-up problems will always function as an equalizer to prevent turbo cars from dominating in F-Prepared.

    Every serious autocrosser is only going to compete in a class where their car can be competitive with the best in the class. Turbo cars have been nothing more than competitive in FP. At this point, there has been no hint of domination or indication that this is imminent, so implementation of additional restrictions is premature and unwarranted.

    - Mark

    Evo8RA
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    22 Apr 2011 02:48 PM
    ratt_finkel wrote:
    Chris speaks the truth. The 38mm restrictor will do nothing to slow down the EVO's. You will see NO appreciable difference in power levels for a properly built motor. All this does is add additional expense in the Evos attaining those numbers.

    Jeremy,

    A 38mm restrictor will limit turbo power output. WRC 34mm restrictors limit turbo power output to approximately 300.

    Mark

    ratt_finkel
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    22 Apr 2011 03:31 PM
    Not according to Kevin. I trust his expertise over anyone else here. Why don't you tell everyone here how much power your car makes Mark and now much you lost with the 52mm restrictor in place.


    P.S. Mine makes 397whp with a 50mm inlet.
    CHRISFP78
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    22 Apr 2011 03:34 PM

    Having won FP a couple of times I have a little experience in the class. I saw the EVO's coming.

    Couple of things. Are you allowed to change the turbo on your car in FP? If so you need to put a smaller turbo on your car. Doing so will give you power much sooner in the rev range and it will only taper off past 6-7 k in line with what the restrictor will do. This will give you a 4 to 5000 rpm power band vs your "claimed" 2000 rpm power band. You will loose power above 7k but you will still have a HUUUUUUUUUUUGe advantage in torque over the NA cars in the class not to metion the traction off the corners. Pro Solo will be yours for the taking over any other FP car other than a SUBI possibly . Having driven a National Champion winning SM RX7 with this set up(small turbo) I know it to be true. That car has no lag over 2,500 rpm right Andy?

    I have no idea what your car has to weigh in the class but I suspect that is where you need help. FYI my car made 305 hp at the rear wheels at 7,200 rpm when I sold it and it was a better car IMO when it make 280 at 6,800 rpm but made 50 more ft lbs of torque at 3,500 rpm.

    Chris

    SmokingTires
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    22 Apr 2011 04:03 PM

    Chris,

    So we should buy these smaller turbos (That don't currently exist, I'm running the stock turbo), and your suggestion still requires 3rd gear to hit 72mph. So constant shift on course to keep up with smaller cars, that can hold 2nd gear.

    So what your saying is I should develope a smaller turbo than the stock one I run now, have an engine built around it, and make less power than a BSP car. I'm sure it's possible, but I can't do it. I don't physically have the money on top of the almost $20k I have spent this year to do this and stay married. I will not be in the class if this happens. And you'll be hard pressed to find anyone who would want to spend all that money to make less power than BSP. It's putting restrictions in place that make the class undesireable to turbo car owners.

    Can anyone honestly tell me they would build a car to this level, and have the choice to spend $10k on an engine and make 550whp and could run XP being very fast, but instead would choose to make 350whp, have a slower car and run FP?

    Jeremy,
    Who is this Kevin, and what is he giving advice on? We never said there shouldn't be a smaller restrictor, just that 38mm is too small.



    Here's a suggestion, give us a limited prep option. BSP rules on your engine, and you can run a 50mm restrictor.

    General Default
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    22 Apr 2011 04:12 PM
    Why are you still talking about the restrictor when the rule 17.11.a says you don't have to use it.
    It supersedes 17.10.c.2.

    The car is classed in the GCR, T2 I think.

    "SIR" is defined in the GCR just as it is used below in 17.11.a.

    You can mix or match the rules sets as stated in 17.11.a

    Kenny Baker

    17.11 OTHER
    A. Vehicles prepared in excess of Solo allowances and prepared up to
    either the current GCR are permitted to compete in their respective
    Prepared classes. Section 17.8.B.7 minimum track requirements ap-
    ply. Minimum weight will be 110% of the Solo minimum weight from
    Appendix A plus any Solo weight penalties (wheel size penalties,
    etc.). Vehicles taking advantage of this allowance may use the Solo
    Rules or the Club Racing GCR (General Competition Rules) allow-
    ances in whole, in part, or in combination. Cars which are not listed
    in the GCR may not use this allowance and are limited to the modi-
    fications allowed in Section 17. For those cars which have been de-
    listed from the current year GCR, the appropriate specifications will
    be developed and added to Appendix A upon member request. An
    exception to the GCR will be that open cars are permitted, provided
    they comply with all provisions of Section 17 pertaining specifically
    to open cars. The following items listed in the GCR, while recom-
    mended, are not required: Logbooks, annual inspections, roll cage,
    on-board fire systems, hand held fire extinguisher, scattershield/
    chain guards, master switch, steering wheel lock removal, window
    safety net, windshield safety clips and rear window safety straps,
    and braided steel brake lines. Single Inlet Restrictors (SIRs) are not
    required.
    Due to the extent of modifications permitted on GT-derived
    cars classed within the Prepared category, it is possible for a replica
    car to meet the legality requirements for the corresponding original
    model provided that the engine, track, and wheelbase remain within
    the allowed specifications. In such a case the replica is considered
    legal for Prepared, provided it correctly meets all of the applicable
    GCR specifications. The 10% increase in minimum weight does ap-ply to such cars.
    vinax
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    22 Apr 2011 04:18 PM

    Can anyone honestly tell me they would build a car to this level, and have the choice to spend $10k on an engine and make 550whp and could run XP being very fast, but instead would choose to make 350whp, have a slower car and run FP?

    Why? Because you COULD win FP next year with that setup. XP on the other hand - pray for a miracle or rain.

    SmokingTires
    Basic Member
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    Posts:263


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    22 Apr 2011 04:24 PM
    vinax wrote:

    Can anyone honestly tell me they would build a car to this level, and have the choice to spend $10k on an engine and make 550whp and could run XP being very fast, but instead would choose to make 350whp, have a slower car and run FP?

    Why? Because you COULD win FP next year with that setup. XP on the other hand - pray for a miracle or rain.

    Hypothetical win, with a hypothetically still competitive car. Find me someone that would honestly do it. I don't think anyone would spend the money to have a slow car. We don't all come here to spend hours standing in a parking lot, for 6 minutes of driving to win. We come out here because it's fun! And the dollar for fun is decent most of the time. But people aren't going to spend a ton of money to have a less fun car than another class.

    ratt_finkel
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    22 Apr 2011 04:29 PM
    Kenny, As the basis for my appeal to the protest. I thought the same thing. Sadly, that's is not the case. A restrictor is not the same as an SIR. Let my DSQ stand as proof of this.
    General Default
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    22 Apr 2011 04:57 PM
    ratt_finkel wrote:
    Kenny, As the basis for my appeal to the protest. I thought the same thing. Sadly, that's is not the case. A restrictor is not the same as an SIR. Let my DSQ stand as proof of this.

    Well it seems to me that the rule needs some clarification. Maybe that was addressed in the decision. The GCR page 160 states that a restrictor is a part of SIR. The only place in the SR that uses SIR is the line that says it is not required. I have to admit I am not an expert on Prepared rules.

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