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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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25 Apr 2011 02:56 PM
How does this work to also slow down the Bmw's and Porshces?
CHRISFP78
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25 Apr 2011 03:37 PM
SmokingTires wrote:
Tom,

I would think a 41mm restrictor with an adjusted weight penalty for turbos would be an improvement. From the math I have found (33mm being about 290hp by WRC numbers with 35psi, so (41x41)/(33x33), you would get a 54.3% increase), it would be at about 450hp,which would be around 380-390whp(feel free to correct me if I am wrong, I did my research on the internet after all). That should give some breathing room on the engines to rev higher. That puts it in about the same power range as the GT3's. It still puts restriction that will require tuning and some building around. You could make the turbo weight adjustment .450 instead of .375. That would the AWD car's 2.0L and larger up to the maximum 2500lbs, and the 2.0L 2WD cars like the Saturn Sky Redline and MR2 would be at 2400lbs making them less of a concern for destroying the class as well. It the rules can always adjusted down later if the car does prove to still be an over-dog.

If you can get your car to 2,500 lbs you won't need 450 horse power. As I and now others have posted you need a smaller turbo and a second gear good for 70 mph. With the 38 mm restrictor you would be making more than double the torque of any other NA car in the class at 3000 rpm. IMO I think the proposed restrictor size is correct.

Look at it another way. My car made about 300hp at the wheels and weighed 2,430 lbs w/o driver and won 6 national championships. Your car with all wheel drive, twice my torque, and only 70 lbs heavier should dominate the class with the same horse power. All of your other arguments are based on price to play and that is not an argument you can stand on in racing. The FP rules set should not be changed for the new car in the class but rather kept stable to protect the investment of all the other loyal competitors in the class. You have to make the investment in the class first and then get adjustments if the car is not competative.

Aufaber
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25 Apr 2011 05:07 PM
CHRISFP78 wrote:


If you can get your car to 2,500 lbs you won't need 450 horse power. As I and now others have posted you need a smaller turbo and a second gear good for 70 mph. With the 38 mm restrictor you would be making more than double the torque of any other NA car in the class at 3000 rpm. IMO I think the proposed restrictor size is correct.

Look at it another way. My car made about 300hp at the wheels and weighed 2,430 lbs w/o driver and won 6 national championships. Your car with all wheel drive, twice my torque, and only 70 lbs heavier should dominate the class with the same horse power. All of your other arguments are based on price to play and that is not an argument you can stand on in racing. The FP rules set should not be changed for the new car in the class but rather kept stable to protect the investment of all the other loyal competitors in the class. You have to make the investment in the class first and then get adjustments if the car is not competative.

I'd listen to Chris, they changed the rules because of his old car. He certainly knows the class. The formulas have changed since his car ran, our car weighs 2096 lbs and makes 230-240hp or so. The car is fast because Toby has spent HUGE amounts of time designing and tuning the suspension.

I'm personally still of the opinion that most of the adjustment should be done with weight. Removing the maximum weight or at least raising it to 2900, and changing the forced induction modifier to somewhere around +.580.

Tom Berry in his BSP Evo usually runs within a second of Toby in his FP car at local events. Seems like taking almost 500lbs out of the car alone and going to slicks would net him a second, let alone the ability to fix the suspension issues that the EVO has.

SmokingTires
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25 Apr 2011 08:21 PM
Chris,

Mark's Evo weighs in under 2300lbs before ballast. My car will be at 2400lbs within the next month(I was 2860 in Mineral Wells). Even with the 4.11 final drive now in my car, at 8000RPM, my car tops out at 71mph. So loosing too much breathing to make sure of high RPM requires substantial compromises. Either I have to stamp return to sender on my new transmission, get the stock 4.529 and A) make a constant 2-3-2 shift or B) Try to hold 3rd gear and give up in the slow speed corners to boost lag. I don't have the info to confirm or deny Kevin's info, but it is pretty safe to assume it was dyno work done in 4th gear, which would have a later spool in 2nd gear.

As Zack added above, power to weight ratio can be referenced. A 2500# Evo with roughly 390whp would be about 6.4#/1hp, which would be in the middle of the other cars in the class. The car will make more torque, but it's also heavier on the same tires. I haven't done a side by side, but I imagine the Evo is at least a few inches wider due to from suspension spacing (no wear to tuck tires in the front), and has worse suspension design.

Aaron,

I wonder what suspension issues your talking about? If by that you mean the strut front suspension, then yes. If I was an engineer, I would already be working on a double a-arm setup for the car. But I'm not :lol:

Dave Hardy
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26 Apr 2011 09:29 AM
A properly built autox turbo engine should NEVER see lag on course.
kevind
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26 Apr 2011 10:23 AM
SmokingTires wrote:
Chris,

Mark's Evo weighs in under 2300lbs before ballast. My car will be at 2400lbs within the next month(I was 2860 in Mineral Wells). Even with the 4.11 final drive now in my car, at 8000RPM, my car tops out at 71mph. So loosing too much breathing to make sure of high RPM requires substantial compromises. Either I have to stamp return to sender on my new transmission, get the stock 4.529 and A) make a constant 2-3-2 shift or B) Try to hold 3rd gear and give up in the slow speed corners to boost lag. I don't have the info to confirm or deny Kevin's info, but it is pretty safe to assume it was dyno work done in 4th gear, which would have a later spool in 2nd gear.

As Zack added above, power to weight ratio can be referenced. A 2500# Evo with roughly 390whp would be about 6.4#/1hp, which would be in the middle of the other cars in the class. The car will make more torque, but it's also heavier on the same tires. I haven't done a side by side, but I imagine the Evo is at least a few inches wider due to from suspension spacing (no wear to tuck tires in the front), and has worse suspension design.

Aaron,

I wonder what suspension issues your talking about? If by that you mean the strut front suspension, then yes. If I was an engineer, I would already be working on a double a-arm setup for the car. But I'm not :lol:

i did my estimations by using the turbo maps provided by garrett on their webpage. the turbine maps tell when your mass flow will be sufficient to reach the desired boost, and that particular turbo is very small, and requires a lot less mass flow then most other turbos. so i don't have any dyno numbers to verify it with directly, but i do have a number of different garrett turbo data logs to help estimate the mass flow required for the desired boost. regardless, they do make small turbos that will give you boost in the mid-low 2000rpm range, its just a matter of selecting the right one.

vinax
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26 Apr 2011 01:31 PM
SmokingTires wrote:
Chris,

Mark's Evo weighs in under 2300lbs before ballast. My car will be at 2400lbs within the next month(I was 2860 in Mineral Wells). Even with the 4.11 final drive now in my car, at 8000RPM, my car tops out at 71mph. So loosing too much breathing to make sure of high RPM requires substantial compromises. Either I have to stamp return to sender on my new transmission, get the stock 4.529 and A) make a constant 2-3-2 shift or B) Try to hold 3rd gear and give up in the slow speed corners to boost lag. I don't have the info to confirm or deny Kevin's info, but it is pretty safe to assume it was dyno work done in 4th gear, which would have a later spool in 2nd gear.

Man seriously - it sucks to be you or anyone with an Evo. Seriously if you expected stability in rules or keep costs in control you should have got a 240Z... you must have had a fair idea of what was going to happen to "overdogs" like the Evo in FP... its happened before. Personally I agree with AUFABER - add weight to the turbo cars. I wouldnt have them spend more $$ to keep the car just as fast as it was before the restriction. I'm pretty sure the Evo guys will prefer a couple of hundred pounds (which they could put in the back) over a 38mm restrictor especially since it could be bolted to the back and improve the weight distribution.

BTW I've got a dog in this fight too. A 2400lbs E36 w/ 250whp. The brick wall I've hit is cost of further engine development. A race-prepped BMW motor will cost about 2 times as much as a 240Z 2.8 would would. I'd rather stick with a reliable fairly competitive car that I don't need to throw any further money at in this economy.

Storm
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26 Apr 2011 04:30 PM
This discussion is doing nothing for my confidence levels in bringing a non-turbo "rallycar" to the table..... :/ The cold heart inside me is screaming to build it how you want it, pull the f'ing "F" off the car, stick an "X" on it and go have fun. :)
James L
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26 Apr 2011 11:12 PM
SmokingTires wrote:
As Zack added above, power to weight ratio can be referenced. A 2500# Evo with roughly 390whp would be about 6.4#/1hp, which would be in the middle of the other cars in the class. The car will make more torque, but it's also heavier on the same tires. I haven't done a side by side, but I imagine the Evo is at least a few inches wider due to from suspension spacing (no wear to tuck tires in the front), and has worse suspension design.

But that shouldn't be used as a factor in establishing the Evo's competitiveness in FP, should it?

If the width and suspension are indeed drawbacks in stock form, the Prepared ruleset allows them to be rectified... for the most part.

SmokingTires
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26 Apr 2011 11:54 PM
James L wrote:

But that shouldn't be used as a factor in establishing the Evo's competitiveness in FP, should it?

If the width and suspension are indeed drawbacks in stock form, the Prepared ruleset allows them to be rectified... for the most part.

I'm sure there are improvements to be made. I wouldn't be the one to tell you what relocation would help where. I do know that adding the allowed double A-Arm would only increase the vehicles track in front. I don't know if that would compromise the rear or not. However I do think things like that need to be factored into how the car can be improved in Prepared form, and what benefits can be had. There seems to be a pattern with the Evo builders. I would think if there was something that would be a great improvement, it would be done more often.

bstock05
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03 May 2011 09:29 AM
I think Im missing something, but in simple terms. Are they going to allow bsp cars into fsp if they use a certain restrictor in the turbo inlet
justint5387
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03 May 2011 10:10 AM
It's FP, not FSP.
TeamRX8
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24 May 2011 02:37 AM

legal = welcome

not legal = not welcome

yeah, it's that simple ...

Yarko
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21 Jun 2011 11:14 PM
Where this rule change gets personal--- I run a Mini Cooper S 1.6l S/C. the cooper S has the biggest supercharger that can do the engine any good. the stock inlet feed is < 52mm ID. So the 52mm plate doesn't hurt too much or mess up the engine management. Running a 38mm plate would really kill the engine which doesn't have much anyway.

I'm not running a 2.0 or 2.5 turbo. 200whp would be the cats pajama's for my engine, and when i can afford it i'd like to build it. Perhaps 38mm's nozzeled the right way wouldn't hurt. but it scares me. It could be a risky investment to build. I'd likely just throw away the charger, change the rear skirt and call it a NA cooper in EP.

I already take a 260lb penalty by the 1900lb min weight, as 1600cc, FWD, charged works out to 1640lbs.

The owner of the 2010 SM champion EVO told me that the 52mm plate was enough trouble to keep him from concurrently campaigning it in FP too.

I commented to the PAC possible changes.

1) don't implement this change, or

2) allow stock turbo/chargers with the stock inlet pipe to not have a restrictor, or

3) tier the forced induction weight multiplier with restrictor plate size. i.e. 38mm would be +.375 multiplier, 52mm would be +.500 multiplier.

the 2nd might be a good choice for cars on a budget.
ratt_finkel
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22 Jun 2011 11:34 AM
The funny thing is; even if they kill the boost buggies with a smaller inlet restrictor. It does nothing to slow down the BMW's, Boxsters and older porsches that have already shown themselves to be just as competitive as the datsuns. And we all know it's about keeping the status quo ;)
geewiz
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22 Jun 2011 09:59 PM

One interesting consideration in this discussion is the smaller turbo cars; while I think the solstice/sky cares are not classed in FP (unless I missed that somewhere recently?) I did notice the mazdaspeed miata being classed in the july fastrack. That's a 2068# easily obtainable minimum weight (based on 1840cc) that can easily top 300 horsepower at the wheels with the stock throttle body of 52mm (so I assume a 52mm restrictor plate isn't a problem). And that sounds... competitive :).

And more broadly, I would think that restrictor plates designed to stop 2400# cars from reaching 400-500hp would be ineffective at preventing a 2100# car from reaching 300-350hp. Is the recent miata classification an admission that the latter is a-ok for FP?

-- Glenn

PS: not sure where you got the numbers below, mtbprelude, and what is wheel/crank, etc., but isn't that 914/6 a 2.0L engine? 300HP? If so, WOW, well done somebody :).

mtbprelude wrote:
Another factor not mentioned in this discussion is the power/weight ratio:

FP Z (2.4) - 1900-2100#/240-250hp = 7.6-8.4#/hp

E36 BMW - 1900-2400#/280-305hp = 6.3-7.8#/hp

914/6 - 1900#/300+hp = <6.33#/hp (I'm sure Leeds/Greg know the exact number, I only know that it is a ~$20K+ engine)

911 GT3 - 2500#/415+hp = <6.0#/hp

EVO - w/out restrictor -

2400/ 397 (Jeremy's BSP power) = 6.1#/hp

OR the closest FP build EVO and the outlier in the class as far as #/hp:

2400/440 (Mark's 'low' power) = 5.4#/hp

2400/475 (Mark's 'high' power = <5.1#/hp

(http://www.facebook.com/#!/photo.ph...p;theater)

SmokingTires
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22 Jun 2011 10:10 PM
ratt_finkel wrote:
The funny thing is; even if they kill the boost buggies with a smaller inlet restrictor. It does nothing to slow down the BMW's, Boxsters and older porsches that have already shown themselves to be just as competitive as the datsuns. And we all know it's about keeping the status quo ;)

Or the '95 Impreza L 2.5L being built in OH region. 2025lbs, 250hp+, AWD.

Grantsfo
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30 Jun 2011 02:13 PM
...200 HP to the wheels. That was a dream for me in the FP 2.5 liter powered Boxster. LOL! My last dyno on the car it made about 176WHP. Will be intersting to see what Erik does with the car.

I'm keeping my eye out for a cosmetically damaged 2.9 liter vario cam powered car now. That motor is capable of close to 300 HP in FP spec.
Storm
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10 Jul 2011 01:06 PM
I'm only at 172 to the wheels with the (non-turbo, 2457cc) 2.5 liter Subaru. My goal is to squeeze another 30 down to the ground over the next couple years. The car began it's road to FP in late November. Surely it won't be anything to lose sleep over just yet.

I have yet to form a concrete opinion on what size restrictor would be adequate in preserving parity across the board. Knowing that folks can buy smaller turbos for less than a tire, treat them as wear items and still produce huge power, and more importantly, TORQUE levels....is something that cannot be ignored.
DrJones_CMR
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11 Jul 2011 07:20 AM
geewiz wrote:
...while I think the solstice/sky cares are not classed in FP (unless I missed that somewhere recently?)...

The Solstice and Sky are classed in FP.

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