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Why isn't the FRS killing TTD?


Varkwso
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I thought we just proved you can't really do a +2 exhaust on one of those cars... not with common bolt on parts anyway
Exhaust Diagram for the Subaru BRZ (Scion FR-S is identical)

brzexhaust-diagram-550x271.jpg

Replacing the midpipe and muffler looks like +2 to me. Header and front pipe have cats in them.

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I'm not sure when I can get to a dyno, but I'll look into it, and certainly post up once I do.

 

What about the "over pipe"? It's separate, and flanged from the the header, and the cats. The overpipe + catback might be a worthwhile mod, especially with gutted cats for +3.

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I'm not sure when I can get to a dyno, but I'll look into it, and certainly post up once I do.

 

What about the "over pipe"? It's separate, and flanged from the the header, and the cats. The overpipe + catback might be a worthwhile mod, especially with gutted cats for +3.

You could gut the cat in the header and replace the front pipe for that extra +1 (assuming you're already doing the over pipe/midpipe/muffler).

 

It's funny that replacing just the header would yield +5 but replacing everything else and gutting the cat in the header would be +3.

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In experiments with 944 Spec, it takes quite a bit a weight to substantially slow down an amateur driver (even a good one) much, especially when it can be placed adventagiously as ballast.

 

Intriguing statement...please elaborate. Is it because amateur drivers are for the most part inconsistent when it comes to pounding out fast laps compared to pro drivers? And if that is the case then any minor performance improvement or deterrent has less of an overall effect since our laps times can vary by more than the changes to the car improve or detract?

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I should put this in context. There was some consideration of implementing "rewards" weight some time back, and some testing done in some regions related to this. When you have an amateur driver (even a good one) who is used to driving at a certain level, adding weight (within a reasonable degree 50-100lbs) doesn't change their braking or turn in points, because they have left enough on the table, that they can still accomplish their routine, at the same speed, within the car's envelope. Add in that ballast tends to be mounted low, and may even improve handling to a degree (more equalized corner weights), and the only true penalty left is the cost in acceleration at pure WOT. Up to that point, more throttle can be added to make up for the weight. So it's a small effect on a relatively small proportion of the time.

 

For a pro driver, it's somewhat more linear, as the cars, and driving are already close to ideal, and little is left on the table.

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Where the factory flanges are isn't relavant to what mod you may or may not get charged for.

 

As has been layed out across two threads now...

 

Looks like the chaning that factory header for a common bolt on piece can very easily trigger all 3 exhaust mods (header, other piping, cat) - it's just the way its constructed. Over pipe seems like it could just trigger other piping. Front pipe will likely trigger cat and other piping. Midpipe and muffler - other piping seems straight forward on those.

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Where the factory flanges are isn't relavant to what mod you may or may not get charged for.

 

As has been layed out across two threads now...

 

Looks like the chaning that factory header for a common bolt on piece can very easily trigger all 3 exhaust mods (header, other piping, cat) - it's just the way its constructed. Over pipe seems like it could just trigger other piping. Front pipe will likely trigger cat and other piping. Midpipe and muffler - other piping seems straight forward on those.

 

 

Ken, I only bring up the flanges, because it looks like you can replace the "over" pipe without altering the cats at all (cleanly/clearly). Replacing the over pipe, and a cat back exhaust would then only be +2 if you didn't have the point to spend on gutting the cats, or live where they smog cars. The over pipe is rumuroed to be somewhat restrictive on thes cars, though it may not be an issue with stock cats in place - remains to be seen.

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Where the factory flanges are isn't relavant to what mod you may or may not get charged for.

 

As has been layed out across two threads now...

 

Looks like the chaning that factory header for a common bolt on piece can very easily trigger all 3 exhaust mods (header, other piping, cat) - it's just the way its constructed. Over pipe seems like it could just trigger other piping. Front pipe will likely trigger cat and other piping. Midpipe and muffler - other piping seems straight forward on those.

 

 

Ken, I only bring up the flanges, because it looks like you can replace the "over" pipe without altering the cats at all (cleanly/clearly). Replacing the over pipe, and a cat back exhaust would then only be +2 if you didn't have the point to spend on gutting the cats, or live where they smog cars. The over pipe is rumuroed to be somewhat restrictive on thes cars, though it may not be an issue with stock cats in place - remains to be seen.

 

Yes, leaving the header stock and the frontpipe stock would be a +2 only; however, thus far the 86s have responded best to header upgrades and a tune... and that's where the deal breaker is.

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Where the factory flanges are isn't relavant to what mod you may or may not get charged for.

 

As has been layed out across two threads now...

 

Looks like the chaning that factory header for a common bolt on piece can very easily trigger all 3 exhaust mods (header, other piping, cat) - it's just the way its constructed. Over pipe seems like it could just trigger other piping. Front pipe will likely trigger cat and other piping. Midpipe and muffler - other piping seems straight forward on those.

 

 

Ken, I only bring up the flanges, because it looks like you can replace the "over" pipe without altering the cats at all (cleanly/clearly). Replacing the over pipe, and a cat back exhaust would then only be +2 if you didn't have the point to spend on gutting the cats, or live where they smog cars. The over pipe is rumuroed to be somewhat restrictive on thes cars, though it may not be an issue with stock cats in place - remains to be seen.

 

Yes, leaving the header stock and the frontpipe stock would be a +2 only; however, thus far the 86s have responded best to header upgrades and a tune... and that's where the deal breaker is.

 

And this is where we bring up all cars have their warts. Still 5 points gets enough rwhp to reach maximum power to weight which isn't too shabby either.

 

Peter

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And this is where we bring up all cars have their warts. Still 5 points gets enough rwhp to reach maximum power to weight which isn't too shabby either.

Peter

 

Sure does... and locks my car in at 225 A6s (9pts), Header/Exhaust (5pts), Coilovers (5pts). Gonna give it a shakedown at RA in March, and probably have a hot shoe take it out and see how close it comes to the 1:36.

I'm already down to 2775 lbs with me and 3/4 tank so any reclass (wt/star) will be really sad, but alas, that's the name of the game. Gonna have to make sure the car is filled up every time.

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You are at that weight with just those mods and the spare/tools removed, and everything else stock with driver? I haven't had a chance to weight the car low on fuel in its current state. Might have to do the same with fuel.

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Where is the fuel tank located in those cars? (thinking ballast + less fuel may be a more optimal distribution)

At a quick glance, rearward over the rear wheels, across the width of the car split around the mid pipe. I'll confirm that with a few other guys who have likely looked at it. But I doubt I can do less fuel, this car is gulps 1/4 tank at Road Atlanta after 6 laps. Would hate to drop below base weight if any additional weight is added to the rules.

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Where is the fuel tank located in those cars? (thinking ballast + less fuel may be a more optimal distribution)

...But I doubt I can do less fuel, this car is gulps 1/4 tank at Road Atlanta after 6 laps...

That's why he's saying ballast + less fuel. If you, for instance, check cross weights of the car with a full tank and a 1/2 tank, is it better/more ideal with 1/2 tank? If so, place enough ballast in an optimal location to maximize being able to drive the car with between 1/4 and 3/4 tank.

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You are at that weight with just those mods and the spare/tools removed, and everything else stock with driver? I haven't had a chance to weight the car low on fuel in its current state. Might have to do the same with fuel.

Yup, I'm 175lbs with suit+helmet+hans+gloves+shoes. Car is 2680 with ~2gals of fuel

 

Exhaust setup: (-30.6 lbs)

Borla UEL Header: 10.9 lbs vs 21lbs stock

Borla Cat Delete (front+overpipel): 6.7lbs total vs 16.9 stock

Borla CatBack Exhaust: 28.1 vs 38.4lbs stock

Battery: (-26.3 lbs)

Shorai LFX14L2-BS12 Battery: 2lbs (3.6 lbs total with battery mount) -

Coilovers(-10lbs from stock)

Wheels & Tires (-16lbs total)

 

Add 50 lbs of junk in the trunk, see how that easily gets below 2600 before I get in the car.

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Where is the fuel tank located in those cars? (thinking ballast + less fuel may be a more optimal distribution)

...But I doubt I can do less fuel, this car is gulps 1/4 tank at Road Atlanta after 6 laps...

That's why he's saying ballast + less fuel. If you, for instance, check cross weights of the car with a full tank and a 1/2 tank, is it better/more ideal with 1/2 tank? If so, place enough ballast in an optimal location to maximize being able to drive the car with between 1/4 and 3/4 tank.

 

I certainly understand. I'm just dreading the need to add 110 lbs of ballast!!! or something like that.

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I certainly understand. I'm just dreading the need to add 110 lbs of ballast!!! or something like that.

What's your tank? 12gal? 13gal? 1/2 tank would be roughly 35-45lbs.

 

Also if you do the ballast + less gas route and *if* the FRS/BRZ are hit with a higher base weight, you're already prepared with ballast and just have to 1) go back to running more gas 2) add more ballast or 3) both to reach an ideal balance.

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What's your tank? 12gal? 13gal? 1/2 tank would be roughly 35-45lbs.

13.2. By my calculation on the scales, full tank until the gas light came on (2gal remaining) netted about 75lbs. So that's right.

 

Also if you do the ballast + less gas route and *if* the FRS/BRZ are hit with a higher base weight, you're already prepared with ballast and just have to 1) go back to running more gas 2) add more ballast or 3) both to reach an ideal balance.

True, I've kept the balance as close to stock as possible, with the full tank keeping the weight centered in the rear... but it'll be advantageous to be able to move weight around as needed if it comes to that.

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Since I am still getting used to the fine details of the rules;

 

The car weight is listed at 2775 with driver in the rules or points will be added for weight reduction, based on how much less. The base for the class is that all cars maintain a certain ratio of 14.25:1 in TTD and meet the mod points requirements. It wouldn't really be a "re-class", but if a competitor submitted dyno results and their BRZ/FRS makes 190 on a dynojet corrected properly, etc. that would mean the car would have a Min. 2707lbs to stay in TTD? Or am I looking at that incorrectly?

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For the letter TT classes you have to be legal in both areas, but by and large most people's cars run out of points first. The adjusted hp/weight stuff is a final check/balance to try and keep all cars competing in the class in the same rough ballpark (and in the number TT classes it's all that matters).

 

6.1.2 spells out the details of how the ratio is checked for compliance if you're really wanting to delve into the minutia.

I don't expect that to change materially for 2014.... Greg would know for sure though

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Since I am still getting used to the fine details of the rules;

 

The car weight is listed at 2775 with driver in the rules or points will be added for weight reduction, based on how much less. The base for the class is that all cars maintain a certain ratio of 14.25:1 in TTD and meet the mod points requirements. It wouldn't really be a "re-class", but if a competitor submitted dyno results and their BRZ/FRS makes 190 on a dynojet corrected properly, etc. that would mean the car would have a Min. 2707lbs to stay in TTD? Or am I looking at that incorrectly?

 

Not complicated BUT once you get under 3200# you have to factor in a .5 mod factor for your weight to hp. Ken will correct me if I am wrong. Also need to factor in the correction factor for smaller tire 245 or less of .8

 

Peter

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Yea, make sure you avoid going below 2775 lbs at any cost for this car in TT/PT. Its tough arguing "I wasn't trying to cheat" in a case like that. I wouldn't worry about power to weight right now unless you're pushing 205+rwhp

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