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Last Post 23 Nov 2012 05:16 PM by  TeamRX8
RX-8 to DSP?
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Chiketkd
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05 Nov 2008 09:54 PM
    As the RX-8 is now in STX for the '09 season, the topic has been raised on other forums about whether the car should be re-classed to DSP. The most capable cars currently in this class "appear" to be:

    -E30, E36 & E46 3 series BMW's
    -ITR
    -IS300
    -Impreza 2.5RS

    The '04-'09 RX-8 is similar in size, weight and whp to the E36 BMW's, but comes with a peaky ITR powerband with a similar lack-of-torque achilles heel. I personally don't see it being dominant in this class, but it'll be course dependent whether one could come out on top. 

    In BSP the car is a lame dead-duck. There's no way it can compete with even the perceived mid-pack cars such as the S2000, C4 vette or E36 M3.

    Thoughts? I'm thinking of writing a letter to the SEB but I'm interested in what others have to say about this...

    mwood
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    05 Nov 2008 10:29 PM

    Well...the RX8 is a popular autocross car, they have strong aftermarket support, are relatively inexpensive, you don't have any problem finding the "right" model to build on, they're fun to drive and easy to work on...So, yeah, I think it is a good idea to find a suitable home for the car in SP and DSP makes the most sense...they sure as heck don't fit in BSP or CSP.

    However, I'm going to guess the BMW guys are going to find flaws in this idea...[;)]

    DSPBMW
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    06 Nov 2008 12:43 AM

    Well not necessarily.

    What kinds of whp/whtq?

    Weight?

    Width?

    Max tire size within stock body confines?

    Go from there.

    gavin
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    06 Nov 2008 04:19 AM

    Chiketkd wrote:
    There's no way it can compete
    Im not a BMW guy, but I do have a question about this statement. "no way"...why not? Or another way I suppose, has anyone actually built a "real" BSP RX8 to compare to the existing cars in BSP, or is this all theoretical/hypothetical? Lobbying for a change in class when a prepped example hasnt turned a wheel in anger yet seems...a bit premature (especially given that ST prep and SP prep arent 100% direct corrolaries). Maybe Im not seeing the urgency here.

    Gavin

    solo-x
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    06 Nov 2008 07:22 AM

    Put the RX8 in DSP and you'll render everything else uncompetitive. The "lack of torque" argument is a crock. What the motor puts out at the crank doesn't matter, what it puts out at the wheels does. And when you take a motor that winds to 9k+ but still only does low 60's in 2nd gear and compare it to a motor that only winds to 7k that goes to the same low 60's and the torque differences get small. The RX8 doesn't have the suspension ailments of the BMW's either. Yeah, the BMW is a good car, but you are constantly working around the poor suspension design. A high CG, poor roll center location, etc. The RX8 doesn't have any of those problems. It has a suspension design on par with the ITR, but without the poor weight distribution and wrong wheel drive.

    The 8 is a sports car. I don't think it should be in BSP, but CSP doesn't seem wrong to me. It fits with the other types of cars in that class. The idea of putting the 8 in DSP is on par with putitng the s2000 in DSP, and that makes no sense either. Both of those cars should be in CSP. Will that ruin the Miata's competitiveness? Hard to say. The miata still has a huge size and weight advantage, so you're probably looking at some amount of course dependancy.

    SP classing based on ST classing is absurd. ST tires tend to equalize things much more then anything else. Put 285 Hoosiers and a suspension on the 8 and watch it pwn DSP.

    Mooobunnny
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    06 Nov 2008 09:36 AM
    solo-x wrote:

    Put the RX8 in DSP and you'll render everything else uncompetitive. 

     

    +1

     

    Isley would have trophied this year in DSP on 245 Kumho's in his BS RX8 and he drove in worse conditions (earlier in the week and day). I am quite sure 2 inches more wheel, 2 inches more tire, coilovers, lighter clutch/flywheel, lightweight seat/batery/brakes and bolt-ons (including unlimited intake modifications) would pick up well more than the additional .9 seconds needed for Isley to win DSP.

    Chiketkd
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    06 Nov 2008 09:56 AM

    DSPBMW wrote:
    What kinds of whp/whtq?

    Weight?

    Width?

    Max tire size within stock body confines?

    Go from there.

    The highest dyno numbers I've ever seen for an n/a RX-8 is 220whp and ~160wtq when Sipe dyno'd his STU car. MOST RX-8's even with cat delete pipes, and a full set of SP legal mods dyno somewhere in the 200-210whp range with about 150wtq.

    If the a/c was deleted, race seats added, etc, an SP RX-8 should be able to get into the mid-to-low 2,700lbs range (obviously weight will be added back on with big wheels & tires).

    Per Edmunds: RX-8 = 69.7" [url]http://www.edmunds.com/used/2005/ma...;/url]

    E36 BMW = 67.3" [url]http://www.edmunds.com/used/1997/bm...;/url]

    Max tire - I've seen *pinched* 285 and 295 tires fit under the fenders on BS RX-8's. A 305 tire should fit w/o cutting the fenders -- Rowse and Speidell used a similar size on their DSP winning BMW this year.

    gavin wrote:
    Im not a BMW guy, but I do have a question about this statement. "no way"...why not? Or another way I suppose, has anyone actually built a "real" BSP RX8 to compare to the existing cars in BSP, or is this all theoretical/hypothetical? Lobbying for a change in class when a prepped example hasnt turned a wheel in anger yet seems...a bit premature (especially given that ST prep and SP prep arent 100% direct corrolaries). Maybe Im not seeing the urgency here.

    Gavin

    Gavin,

    I'm not sure someone in their right mind would build one. Let's look at a perceived mid-pack BSP car -- the S2000:

    • The 2.2L S2000 motor makes more power and torque in SP trim than an RX-8 (240+whp & 170+wtq iirc)
    • A BSP S2000 should be in the 2,500lbs range (AP1 AS S2000's can touch the upper 2,500's)
    • The S2000 is narrower and has a smaller wheelbase than the RX-8 making it more nimble/tossable

    All of these are in the favor of the S2000 and Jason Uyeda previously campaigned his. While he trophied in the car, he was well back from the Berry evo and has since moved onto a different class. Why would an RX-8 fair any better?

    SerNick
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    06 Nov 2008 11:01 AM
    Chiketkd wrote:


    Gavin,

    I'm not sure someone in their right mind would build one. Let's look at a perceived mid-pack BSP car -- the S2000:

    • The 2.2L S2000 motor makes more power and torque in SP trim than an RX-8 (240+whp & 170+wtq iirc)
    • A BSP S2000 should be in the 2,500lbs range (AP1 AS S2000's can touch the upper 2,500's)
    • The S2000 is narrower and has a smaller wheelbase than the RX-8 making it more nimble/tossable

    All of these are in the favor of the S2000 and Jason Uyeda previously campaigned his. While he trophied in the car, he was well back from the Berry evo and has since moved onto a different class. Why would an RX-8 fair any better?

     

    On a dynapack I've seen 245 and 170 from a car with Toda Cams. Not with stock cams. Don't know where you are getting that number from. Also - the early AS cars can only get to the low 2700's. And there is only a difference of less than 100lbs across all the models AP1 and AP2 with or without the glass window.

     

    There isn't a whole lot to lose going from AS to BSP for an S. I could see 200lbs but thats about it - that includes removing the 60lb soft top.  

    solo-x
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    06 Nov 2008 11:06 AM

    Chike, you sure it's gonna be that heavy? You're talking DSP E36 BMW weight, but the motor in the 8 is way lighter then that big 6 in the bmw. yeah, other stuff plays into the total weight, but the single biggest chunk of weight is the motor. I'd figure closer to high 2500's. At any rate, the BMW is making due with a horrible suspension design compared to the 8.

    The s2000 failing to compete well against an EVO isn't reason to class the 8 differently. How do you know a BSP 8 wouldn't be right with a BSP s2000? BS vs. AS, the 8 and s2k are neck in neck, aren't they?

    ChrisFranson
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    06 Nov 2008 11:17 AM

    Chiketkd wrote:
     MOST RX-8's even with cat delete pipes, and a full set of SP legal mods dyno somewhere in the 200-210whp range with about 150wtq.

    Then power is on par with the E36 BMW, with an actually functional suspension. Nate seems to be demonstrating that torque really isn't necessary to go fast in DSP. Given the Mazda contingency money and cheap parts available, I know what I'd choose to drive in DSP if the RX-8 were moved there.

    DrJones_CMR
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    06 Nov 2008 11:58 AM
    Just throw it in ESP! [6]
    Chiketkd
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    06 Nov 2008 12:12 PM

    SerNick wrote:
    On a dynapack I've seen 245 and 170 from a car with Toda Cams. Not with stock cams. Don't know where you are getting that number from. Also - the early AS cars can only get to the low 2700's. And there is only a difference of less than 100lbs across all the models AP1 and AP2 with or without the glass window.

    There isn't a whole lot to lose going from AS to BSP for an S. I could see 200lbs but thats about it - that includes removing the 60lb soft top.

    Nick,

    I remember seeing a 240/170 number somewhere, but it was a while ago and I'm not sure if it was on race gas (which of course is legal). What would you say are more reliable SP whp & wtq numbers for the 2.2L S2000 motor? Also, looking at the AS weight thread again, I mis-stated the numbers - seems like an AP1 S2000 can get down to the upper 2,600lbs range. [url]http://sccaforums.com/forums/thread...;/url]

    I see even less weight savings for an RX-8 going from BS to BSP as we have no soft top to remove. Like the S2000, the stock seats are already relatively light and most weight savings will come from removing the a/c system, lightened pulleys, clutch, flywheel, etc. A good BS RX-8 is right around 2,800lbs - so I imagine an SP car will drop a net of ~100lbs (obviously weight will be added back with extra suspension braces, big wheels & tires).

    solo-x wrote:

    Chike, you sure it's gonna be that heavy? You're talking DSP E36 BMW weight, but the motor in the 8 is way lighter then that big 6 in the bmw. yeah, other stuff plays into the total weight, but the single biggest chunk of weight is the motor. I'd figure closer to high 2500's. At any rate, the BMW is making due with a horrible suspension design compared to the 8.

    The s2000 failing to compete well against an EVO isn't reason to class the 8 differently. How do you know a BSP 8 wouldn't be right with a BSP s2000? BS vs. AS, the 8 and s2k are neck in neck, aren't they?

    Nate,

    I'm +ve the RX-8 can't be anywhere near the 2,500lbs range in SP. An S2000 could probably get there, but definitely not the RX-8. A stock class AP2 S2000 has more power & torque and weighs ~100lbs less. They aren't neck-and-neck unfortunately...

    ChrisFranson wrote:
    Then power is on par with the E36 BMW, with an actually functional suspension. Nate seems to be demonstrating that torque really isn't necessary to go fast in DSP. Given the Mazda contingency money and cheap parts available, I know what I'd choose to drive in DSP if the RX-8 were moved there.

    Correct - weight and power between the two cars are on par. The BMW obviously makes more torque while the RX-8 has a good suspension like the ITR. I've seen a DSP dyno on bimmerforums for the 2.8L motor where the car made ~205 whp and 200wtq on pump gas. The OP did state he did no high dollar build so more power was in the motor. Obviously an E46 DSP car with the 330i motor will make more power, but has a bigger weight penalty that comes with it.

    Lack of torque makes things course dependent though.

    Don't get me wrong folks, I'm not hell bent on getting the RX-8 moved to DSP - but on paper the car seems out-of-place for BSP and CSP.

    Chiketkd
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    06 Nov 2008 12:16 PM

    DrJones_CMR wrote:
    Just throw it in ESP! [6]

    ESP is too slow! Shchipkov's E30 would already beat up on all of them... [:P]

    P.S. All bets are off though if Strano and/or Madarash are on their game!

    RX7 KLR
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    06 Nov 2008 12:40 PM
    solo-x wrote:

    The RX8 doesn't have the suspension ailments of the BMW's either. Yeah, the BMW is a good car, but you are constantly working around the poor suspension design

    I agree that the RX-8 has a much better suspension design from the factory, but that also means you have less to gain/fix when you go to SP. In SP you can fix lack of camber, poor spring rates, roll issues etc, these are not areas where you would see a big improvement in the RX-8. The BMW on the other hand should see massive gains just by getting some camber. Additionally there are already BS cars running the SP size tires (285+), so the only gain in that dept is wheel width.

    No matter what you do to an RX-8 in SP it will always weigh more (up to 200lbs by my calculations) than an S2000, and have less HP/Tq, and the S2K is not nearly a top dog in BSP. Sure looks to me like a better match for the 3 series in DSP.

    mwood
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    06 Nov 2008 12:55 PM
    Hey, everyone's always suggesting that classes getting "faster" is natural and not a bad thing...how long has the 3-series been top dog in DSP, anyhow? And, the fact is the E46 is just getting developed and (with Doug's great driving) already proven to be the "best"...hmmm...maybe this RX8 to DSP is a good idea...
    jeffh
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    06 Nov 2008 01:19 PM
    Let's make note here that the Rx-8 could only have 100ft-lbs of torque but "if" it had 15:1 overall ratio in 2nd with a flat torque curve up to 13k, it would be accelerate just as fast any BMW in the class. Engine torque and horsepower numbers are useless without looking at the whole picture. With the new rear end ratio, the RX-8 should accelerate with any BMW. The car could be slightly faster but some of the new tubo FWD cars could also be pretty fast if of course they are able to get the power down.
    Chiketkd
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    06 Nov 2008 01:31 PM

    RX7 KLR wrote:
    Sure looks to me like a better match for the 3 series in DSP.

    The dimensions, whp and weight in SP trim are very similar between the RX-8 and E36 3 series. One question Jason, how far back are you from the top DSP drivers at national level events (Tours, Divisionals, etc)? I know Sias occasionally brings his DSP car out to play...

    RX7 KLR
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    06 Nov 2008 01:42 PM
    Chiketkd wrote:

    One question Jason, how far back are you from the top DSP drivers at national level events (Tours, Divisionals, etc)? I know Sias occasionally brings his DSP car out to play...

    I beat DSP at the SD tour, only tour I ran in 2008, but Rowse coned every run both days. [:$]

    At the SD divisional Rowse was a 143.9 and I had a 146.4. At the LA divisional Heitkotter ran a 153.0 in BS, I was .2 back. Rowse had one clean run the whole weekend, Speidell won DSP with a 152.4. I don't know at what point they changed to the 305s they won natls on, and I thought that I heard at natls they were still making suspension changes including a shock rebuild/revalve by Koni. I also doubt they have built a motor, and I hear the car still has AC. I guess the Deliot's can chime in on their level of prep - but I doubt it is 100%, as that is not the AZ way to do SP. [;)]

    solo-x
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    06 Nov 2008 02:23 PM
    RX7 KLR wrote:
    solo-x wrote:

    The RX8 doesn't have the suspension ailments of the BMW's either. Yeah, the BMW is a good car, but you are constantly working around the poor suspension design

    I agree that the RX-8 has a much better suspension design from the factory, but that also means you have less to gain/fix when you go to SP. In SP you can fix lack of camber, poor spring rates, roll issues etc, these are not areas where you would see a big improvement in the RX-8. The BMW on the other hand should see massive gains just by getting some camber. Additionally there are already BS cars running the SP size tires (285+), so the only gain in that dept is wheel width.

    No matter what you do to an RX-8 in SP it will always weigh more (up to 200lbs by my calculations) than an S2000, and have less HP/Tq, and the S2K is not nearly a top dog in BSP. Sure looks to me like a better match for the 3 series in DSP.

    You can't fix the BMW's mac struts, rear trailing arm, and other suspension pickup points though. The e36 BMW has already exceeded the limits of the suspension design. That's why they bicycle so often already and why Shields nearly put his car on its lid at the Toledo Pro this year. Give the RX8 the same suspension improvements (stiffer springs, more camber, etc) and the 8 will out handle the BMW by A LOT. The e46 doesn't seem to be as cursed.

    I don't mind having the class improve in speed. The current cars though all have a major handicap. The BMW's have weight, cg height, and suspension design. The ITR has driveline. The e30 has power and suspension design. The 2.5RS has power, suspension design, and weight. Where is the handicap that the 8 is cursed with?

    You can't use PAX to say that the 8 won't be competitive in CSP. To say that, you would then have to say the miata would be competitive in BSP. Leave PAX out of it. An 8 is much closer to a CSP type car then a DSP type car. Yeah, the 8 is heavier then a miata, and wider too, but it has a bunch more power. A CSP 8 would look a lot like the new miata in CSP, would it not?

    E. Campbell
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    06 Nov 2008 02:26 PM

    RX8 to DSP would be the same as sending the M3's to DSP along with the S2k. C4's would eventually fall apart thus eliminating BSP diversity to turbo all wheel car class. I now nothing about RX8s, they must have a double A arm suspension with 10 degrees of caster up front per claimed superior suspension design? You might as well move RS's and front drive DSP cars to FSP. High roll center makes you transition around the cones better or not.

    New SP classes

    1. ASP supercar class

    2. BSP turbo all wheel class

    3. CSP no weight no horsepower class

    4. DSP mid weight RWD some horsepower class

    5. ESP same old muscle cars

    6. FSP FWD and everything else claimed as a car class CRX included

    This would probably stabilize course dependence. If a new car comes along it shouldn't be moved back and forward in classing, it will either be competitive or not. I dont see a problem this current classing until someone tries to set up a car to the rule book limit and does not succeed.

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