2015 WRX auto-x impressions - Page 8

BlkWRXWag · 01-19-2015, 12:16 PM

First impressions from me...

This car is being built by FRSport and so far they have put on some 15lb Wedsport wheels with 245/40/17 RS3v2s. Also, a titanium catback with huge melon shooter exhaust. Everything else is stock right now.

One thing that surprised me was how much turbo lag there was. Whether I was just expecting too much, does the melon shooter hurt it, or it's just the way it is, I don't know. We are going to try some tests with various catbacks to see if it can be improved. I was having to get on the gas mid turn, and hope that the power would hit as I hit the exit!

Understeer, and more understeer. Not terrible, but just always there. We are running zero toe up front and a little toe in for the rear. For the next event, I have asked them to put it to zero toe in the rear and hopefully we will have a stiffer rear sway bar as well.

Stock shifter without the short shift kit (is that legal?) is really sloppy.

Other than that though, it was very impressive and the clock said it was fast. Here is my winning run in DS from yesterday which was also the top PAXing street tire time.

YouTube (Short URL)

Next step will be trying to get some 8611 Koni shocks made - stay tuned on that.

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Jeremy1 · 01-19-2015, 01:22 PM

Pretty decent first event. It didn't look like a particularly good course for that car...a whole bunch of 180 sweepers. Seems like you were seldom at full throttle for more than a couple seconds. Must have been a real tire workout. Take any pyrometer data?

Since you're suspicious of the relationship of the cat back to turbo lag, maybe run an event with the original exhaust to see if it's different?

stevesnow · 01-19-2015, 01:37 PM

Turbo lag really isn't going to change noticeably from any catback... Work on late-apexing, and giving it a little throttle mid-turn to get the boost up but not necessarily the tires to start spinning... that's probably you're best bet..

BlkWRXWag · 01-19-2015, 01:42 PM

No pyrometer data - I ended up running 37/44 on tire pressures.

And yes, I was definitely working on getting on the throttle mid turn. I'm no great left foot braker, so I had Tom Berry drive the car to see if that would help. Turns out that the car did not like both pedals being pressed on at the same time, or if it did allow it, it did not help the lag. We both came to the conclusion that just hitting the throttle mid turn was the best bet.

ABQautoxer · 01-19-2015, 05:43 PM

I think you're just a bit rusty from not having driven the STI and you'll have no issues. I learned to get on the gas MUCH earlier driving the GR and the FiST seems like it will be the same. Both make me really wish they had a supercharger instead though.

BlkWRXWag · 01-19-2015, 06:43 PM

My 06 STi had no lag! Now, Annie's 07 Sti was just like this - gas it mid corner. All about getting used to the timing.

ABQautoxer · 01-19-2015, 07:18 PM

Maybe it's just me but I swear the 2015 has a ton less than any STI/WRX I've driven previously, kinda similar to my 06 WRX in full STX prep.

tuskenraider · 01-19-2015, 11:11 PM

Ain't no lag on no 15.

BlkWRXWag · 01-19-2015, 11:15 PM

Quote:

Originally Posted by tuskenraider

Ain't no lag on no 15.

Then what the hell is wrong with my car?! I'm used to Subarus. This is the laggiest thing I have ever driven.

epv · 01-19-2015, 11:42 PM

If you're above 3k you should have ~0.5s or less of lag for 0-100% throttle. I haven't put a clock to it, but it is pretty quick as long as you're not pulling it out of the 2k region (**** you 15 mph turns).

mitchman · 01-19-2015, 11:52 PM

Glad you liked your new ride! Thinking of doing the same thing...

justint5387 · 01-20-2015, 12:01 AM

Max is just missing the BRZ

acemastr · 01-20-2015, 09:38 AM

37/44 pressures? is that cold? I'd have thought lower pressures = more grip = faster time?

(Auto-X noob, genuine question)

Manicdan · 01-20-2015, 09:54 AM

Quote:

Originally Posted by acemastr

37/44 pressures? is that cold? I'd have thought lower pressures = more grip = faster time?

(Auto-X noob, genuine question)

at the last event i did we forgot our gauge and made the huge mistake of using two different once. one said 36 and one said 30, the one we forgot to bring we keep the pressure around 31 front and 30 rear

this is on stock tires. we didnt do too much sidewall testing, i could just feeling it getting incredibly understeery or sloppy as i went too high or low.

different tires also like different pressure settings, in the scca tire test (a thread also in this section), they showed the optimal pressure for each tire and it was a wide difference. all that said i think if i hear anything over 35 i cringe and wonder if i am doing something wrong because i imagine it would be happiest in the lower 30s

Jeremy1 · 01-20-2015, 10:15 AM

Quote:

Originally Posted by acemastr

37/44 pressures? is that cold? I'd have thought lower pressures = more grip = faster time?

(Auto-X noob, genuine question)

Genuine answer. Lower pressures do equal more grip/faster time, but only if the tire tread applies force across it's entire width. As with most stock cars, this car has limited camber adjustment and lots of roll, so the tire bears heavily on the outside shoulder. A bad situation which gets even worse if the tire pressure allows the tire to deform from the uneven contact. High pressures suck, but are needed.

epv · 01-20-2015, 10:33 AM

I was running 38-40 on the front last year for the Sport Maxx RTs. The tires roll over onto the sidewall real easily and the tire will start to hop. Increased pressure helps with this a little bit.

Manicdan · 01-20-2015, 01:27 PM

Quote:

Originally Posted by Jeremy1

Genuine answer. Lower pressures do equal more grip/faster time, but only if the tire tread applies force across it's entire width. As with most stock cars, this car has limited camber adjustment and lots of roll, so the tire bears heavily on the outside shoulder. A bad situation which gets even worse if the tire pressure allows the tire to deform from the uneven contact. High pressures suck, but are needed.

whats your opinion of stiffer sidewall tires or going with bigger rims and shorter sidewalls, think it alleviates any of the problem? (i should just google it)

Jeremy1 · 01-20-2015, 03:14 PM

Stiffer sidewalls (Dunlop) tolerates more tire width on smaller rim. But the uneven tread heating is due to suspension limitation and no tire will get around that. Even though the RS-3 is known to have a softer sidewall, it is still popular on heavier cars...maybe because it handles heat well.

It seemed bizarre but BFG once made stock class autox tires with stiff inner sidewalls and soft outer sidewalls to induce extra negative camber in corners though planned distortion. Doesn't seem like it ever caught on and it's gone now.

Ultimately the best tire choice and pressure choice are found by lap times.

alphaBETA · 01-20-2015, 09:52 PM

I've been debating the size thing lately - still can't decide. Probably going to start out on Hankooks. I didn't try the "V2" Hankooks last year, but I loved the old RS3. It kinda feels like butthole with squishy sidewalls pinched on a narrow rim, but the more aggressive you drive the more heat you could get in and the faster they got.

The Z2's are brilliant as they are sticky on the first run, but overdrive them and they drop off - I got to imagine this is going to be an issue on the front of the WRX. The stiff sidewalls make the car feel good, but I'm not convinced they actually work to your advantage outside of feel. Based on wear and grip I was able to use far more tread of the squishy sidewall RS3 than a stiffer sidewall Rival when pinched.

Size options I'm looking at (Going to need a set of wheels too):

245/40/18 - pretty much guaranteed availability in any future tire, but expect paying +$200 a set premium vs 17s. Rims are a bit more $$ too. Probably the best gearing for fast courses.

245/45/17 - Right now Z2SS is the only option I would consider, but I'm pretty sure I won't want to be on Dunlops once it gets warm out. But I know they are capable if I can keep my shtuff together.

235/45/17 - Cheap option and published tread width for the RS3 is only 0.1" less than the 245/40/18. Taller sidewall might be offset by not trying to put too much tire on a 8" wheel.

255/40/17 - Also cheap - not sure how I feel about the gearing, even if its <2mph difference from the taller 18" option. Leaning toward this one at the moment.

Jeremy1 · 01-21-2015, 12:35 PM

Yeah, I just went through that. I went with the 255 RS-3's. Do they work? Yes. Are they better than the others on your list? Hell if I know. I went with 17's because I had no evidence 18's would be better and it was over a $1000 hit with no guarantee the extra money would buy anything. But I have little confidence I made the right call.

BlkWRXWag · 01-21-2015, 12:43 PM

On a big sweeper course, the 255 RS3 is probably good. On a tighter, more transitional course, I'd pick the 245. The 245 would also reduce lag over the 255, albeit with a reduced top speed.

Z2SS is a little unknown for me right now. I'll wait on others to do the testing. The RS3 works well enough and pays contingency.

Red Army · 01-21-2015, 01:14 PM

Quote:

Originally Posted by BlkWRXWag

On a big sweeper course, the 255 RS3 is probably good. On a tighter, more transitional course, I'd pick the 245. The 245 would also reduce lag over the 255, albeit with a reduced top speed.

Z2SS is a little unknown for me right now. I'll wait on others to do the testing. The RS3 works well enough and pays contingency.

I agree with this.

SPDboyNY · 01-21-2015, 03:56 PM

can someone point out in the 2015 rules where it says the 2015 WRX will be in D-street? I do not see it at all

epv · 01-21-2015, 04:04 PM

Page 166.

ABQautoxer · 01-21-2015, 04:04 PM

Page 166 of the 2015 rulebook draft.

Impreza WRX (non-STI) (2001-
15)

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01-19-2015, 01:22 PM	#177
Jeremy1 Scooby Newbie Member#: 406693 Join Date: Nov 2014 Vehicle: 2015 WRX ice silver	Pretty decent first event. It didn't look like a particularly good course for that car...a whole bunch of 180 sweepers. Seems like you were seldom at full throttle for more than a couple seconds. Must have been a real tire workout. Take any pyrometer data? Since you're suspicious of the relationship of the cat back to turbo lag, maybe run an event with the original exhaust to see if it's different?

01-19-2015, 01:37 PM	#178
stevesnow Scooby Newbie Member#: 387752 Join Date: Apr 2014 Location: Ellicott City, MD Vehicle: 2015 Subaru WRX Prem CVT Galaxy Blue Pearl	Turbo lag really isn't going to change noticeably from any catback... Work on late-apexing, and giving it a little throttle mid-turn to get the boost up but not necessarily the tires to start spinning... that's probably you're best bet..

01-19-2015, 01:42 PM	#179
BlkWRXWag Scooby Specialist Member#: 31821 Join Date: Jan 2003 Chapter/Region: SCIC Location: FRSport.com Vehicle: 2015 DS WRX	No pyrometer data - I ended up running 37/44 on tire pressures. And yes, I was definitely working on getting on the throttle mid turn. I'm no great left foot braker, so I had Tom Berry drive the car to see if that would help. Turns out that the car did not like both pedals being pressed on at the same time, or if it did allow it, it did not help the lag. We both came to the conclusion that just hitting the throttle mid turn was the best bet.

01-19-2015, 05:43 PM	#180
ABQautoxer Scooby Specialist Member#: 198231 Join Date: Dec 2008 Location: Albuquerque, NM Vehicle: 2007 Not a Subaru	I think you're just a bit rusty from not having driven the STI and you'll have no issues. I learned to get on the gas MUCH earlier driving the GR and the FiST seems like it will be the same. Both make me really wish they had a supercharger instead though.

01-19-2015, 06:43 PM	#181
BlkWRXWag Scooby Specialist Member#: 31821 Join Date: Jan 2003 Chapter/Region: SCIC Location: FRSport.com Vehicle: 2015 DS WRX	My 06 STi had no lag! Now, Annie's 07 Sti was just like this - gas it mid corner. All about getting used to the timing.

01-19-2015, 07:18 PM	#182
ABQautoxer Scooby Specialist Member#: 198231 Join Date: Dec 2008 Location: Albuquerque, NM Vehicle: 2007 Not a Subaru	Maybe it's just me but I swear the 2015 has a ton less than any STI/WRX I've driven previously, kinda similar to my 06 WRX in full STX prep.

01-19-2015, 11:11 PM	#183
tuskenraider Scooby Specialist Member#: 65699 Join Date: Jul 2004 Chapter/Region: MWSOC Location: S.S. Chicago Vehicle: 15 WRX WR Blue	Ain't no lag on no 15.

01-19-2015, 11:42 PM	#185
epv Scooby Newbie Member#: 381966 Join Date: Feb 2014 Vehicle: 2015 WRX WRB	If you're above 3k you should have ~0.5s or less of lag for 0-100% throttle. I haven't put a clock to it, but it is pretty quick as long as you're not pulling it out of the 2k region (**** you 15 mph turns).

01-19-2015, 11:52 PM	#186
mitchman Scooby Newbie Member#: 406039 Join Date: Nov 2014 Location: Kennewick, WA Vehicle: 2015 WRX GBP	Glad you liked your new ride! Thinking of doing the same thing...

01-20-2015, 12:01 AM	#187
justint5387 Scooby Newbie Member#: 259697 Join Date: Oct 2010 Vehicle: 2006 WRX STi	Max is just missing the BRZ

01-20-2015, 09:38 AM	#188
acemastr Scooby Specialist Member#: 400510 Join Date: Sep 2014 Chapter/Region: South East Location: Tampa, FL Vehicle: 2015 WRX Limited CVT World Rally Blue	37/44 pressures? is that cold? I'd have thought lower pressures = more grip = faster time? (Auto-X noob, genuine question)

01-20-2015, 10:33 AM	#191
epv Scooby Newbie Member#: 381966 Join Date: Feb 2014 Vehicle: 2015 WRX WRB	I was running 38-40 on the front last year for the Sport Maxx RTs. The tires roll over onto the sidewall real easily and the tire will start to hop. Increased pressure helps with this a little bit.

01-20-2015, 03:14 PM	#193
Jeremy1 Scooby Newbie Member#: 406693 Join Date: Nov 2014 Vehicle: 2015 WRX ice silver	Stiffer sidewalls (Dunlop) tolerates more tire width on smaller rim. But the uneven tread heating is due to suspension limitation and no tire will get around that. Even though the RS-3 is known to have a softer sidewall, it is still popular on heavier cars...maybe because it handles heat well. It seemed bizarre but BFG once made stock class autox tires with stiff inner sidewalls and soft outer sidewalls to induce extra negative camber in corners though planned distortion. Doesn't seem like it ever caught on and it's gone now. Ultimately the best tire choice and pressure choice are found by lap times.

01-20-2015, 09:52 PM	#194
alphaBETA Scooby Newbie Member#: 409824 Join Date: Dec 2014	I've been debating the size thing lately - still can't decide. Probably going to start out on Hankooks. I didn't try the "V2" Hankooks last year, but I loved the old RS3. It kinda feels like butthole with squishy sidewalls pinched on a narrow rim, but the more aggressive you drive the more heat you could get in and the faster they got. The Z2's are brilliant as they are sticky on the first run, but overdrive them and they drop off - I got to imagine this is going to be an issue on the front of the WRX. The stiff sidewalls make the car feel good, but I'm not convinced they actually work to your advantage outside of feel. Based on wear and grip I was able to use far more tread of the squishy sidewall RS3 than a stiffer sidewall Rival when pinched. Size options I'm looking at (Going to need a set of wheels too): 245/40/18 - pretty much guaranteed availability in any future tire, but expect paying +$200 a set premium vs 17s. Rims are a bit more $$ too. Probably the best gearing for fast courses. 245/45/17 - Right now Z2SS is the only option I would consider, but I'm pretty sure I won't want to be on Dunlops once it gets warm out. But I know they are capable if I can keep my shtuff together. 235/45/17 - Cheap option and published tread width for the RS3 is only 0.1" less than the 245/40/18. Taller sidewall might be offset by not trying to put too much tire on a 8" wheel. 255/40/17 - Also cheap - not sure how I feel about the gearing, even if its <2mph difference from the taller 18" option. Leaning toward this one at the moment.

01-21-2015, 12:35 PM	#195
Jeremy1 Scooby Newbie Member#: 406693 Join Date: Nov 2014 Vehicle: 2015 WRX ice silver	Yeah, I just went through that. I went with the 255 RS-3's. Do they work? Yes. Are they better than the others on your list? Hell if I know. I went with 17's because I had no evidence 18's would be better and it was over a $1000 hit with no guarantee the extra money would buy anything. But I have little confidence I made the right call.

01-21-2015, 12:43 PM	#196
BlkWRXWag Scooby Specialist Member#: 31821 Join Date: Jan 2003 Chapter/Region: SCIC Location: FRSport.com Vehicle: 2015 DS WRX	On a big sweeper course, the 255 RS3 is probably good. On a tighter, more transitional course, I'd pick the 245. The 245 would also reduce lag over the 255, albeit with a reduced top speed. Z2SS is a little unknown for me right now. I'll wait on others to do the testing. The RS3 works well enough and pays contingency.

01-21-2015, 03:56 PM	#198
SPDboyNY Scooby Newbie Member#: 250511 Join Date: Jun 2010	can someone point out in the 2015 rules where it says the 2015 WRX will be in D-street? I do not see it at all

01-21-2015, 04:04 PM	#199
epv Scooby Newbie Member#: 381966 Join Date: Feb 2014 Vehicle: 2015 WRX WRB	Page 166.

01-21-2015, 04:04 PM	#200
ABQautoxer Scooby Specialist Member#: 198231 Join Date: Dec 2008 Location: Albuquerque, NM Vehicle: 2007 Not a Subaru	Page 166 of the 2015 rulebook draft. Impreza WRX (non-STI) (2001- 15)