SCCAForums.com

129STS:

snip 

Making something as fast as a SM/SM2/XP/DM/EM car, driveR-ability becomes a increasingly major factor.

fixed that for you. 

---

Chris
51 SM2

ChrisSwearingen:

129STS:

snip 

Making something as fast as a SM/SM2/XP/DM/EM car, driveR-ability becomes a increasingly major factor.

fixed that for you. 

 

I disagree.  Machinery starts to matter more in the faster classes.  In a stock class, the cars are all closer to the theoretical 100% car.  In XP.... right now, nobody is much beyond either a prepared car with a small amount of engine work and aero, or a street prepared car with more motor, no interior, and some aero.

Yes it's hard to win the faster classes, but it's also a different skill than the slower classes IMO.  That's why even Erik, Andy, etc are all still dropping times from one run to the next.  In my old class of ES... you basically had to get that 99.5% run both days at Nationals to win.  In the faster classes, I think you're more aiming to have clean runs on both days that are at least above 90-95%.  Basically, don't make any big mistakes rather than make the perfect run.

At a local this past weekend, on my *5th* run, I dropped 1.9 seconds, and backed it up by going even faster (dirty) on my 6th run.
 

---

Jesse
-2002-2006 E-stock 93 MR2 (sold)
-2007-2008 XP Spyder

129STS:

snip 

At a local this past weekend, on my *5th* run, I dropped 1.9 seconds, and backed it up by going even faster (dirty) on my 6th run.
 

I agree with your observations, but not your conclusions.  On the 5th run was the car easier to drive or did you drive it better?  The higher powered/faster cars are less forgiving.  The power can cause as many mistakes as it overcomes. 

---

Chris
51 SM2

129STS:

At a local this past weekend, on my *5th* run, I dropped 1.9 seconds, and backed it up by going even faster (dirty) on my 6th run.

 At the event, I also improved more on my 5th and 6th runs, but IMO, that was more due to the fact that event was split up with 3 runs in the cold, slightly damp morning, and 3 in the sunny, 65 degree afternoon.  On my 1st afternoon run (4th), I pretty much matched my 3rd run, and realized that there was a good bit of additional grip out there due to the higher temps, cleaner course, and additional rubber laid from the SP/P/M cars.  So, I was able to be over a second faster on my 5th and 6th runs.  My first 4 runs were separated by less than 1 second.  IMO, this event isn't a good set of data to base your conclusion on.  I was working by the last 1/3 of the course in the morning when your car was running, and your car looked to be lacking grip, compared with your kickass runs in the afternoon.

On a side note, I am damn curious what a 200+ hp well setup FWD car on 275/225 hoosiers would be like to drive :)

 -Brian
 

 

---

89/189 STS/STX '89 Civic Si

I wouldn't rule out big aero on a fast fwd car.

You're going to want the rear pretty stiff to limit weight transfer under acceleration, and a big rear wing could let you get away with more rear spring rate.  The car would be looser at low speeds, but much more manageable through a high-speed slalom.



It might be worth talking to Andrew Cordeiro and his brother about the Scirocco they ran in E-Mod this year.  I think that car was 4th after the first day.

---

Robert Puertas
www.EvoSchool.com

Robert Puertas:

I wouldn't rule out big aero on a fast fwd car.

You're going to want the rear pretty stiff to limit weight transfer under acceleration, and a big rear wing could let you get away with more rear spring rate.  The car would be looser at low speeds, but much more manageable through a high-speed slalom.



It might be worth talking to Andrew Cordeiro and his brother about the Scirocco they ran in E-Mod this year.  I think that car was 4th after the first day.

Rearward weight transfer under accel is the same, stiff springs or soft. CG height, wheelbase, and rate of acceleration are all that matters.

The longer the wheelbase, the more power you can use. The more static front weight, the more power you can use. A 100+ inch wheelbase is going to be necessary, and I probably wouldn't exceed 63-64% static front weight distribution. 250whp properly geared, is probably the "sweet spot". More power could occasionally be used, but you'd have diminishing returns. As much front tire as you can possibly fit to keep the tires from burning off the car. You won't need anything more then a 205 on the rear of the car because it isn't carrying much weight at all. Of course, all IMO, YMMV, my .02, etc.
 

---

Nate Whipple
NER
188/88 DSP ITR

solo-x:

Robert Puertas:

I wouldn't rule out big aero on a fast fwd car.

You're going to want the rear pretty stiff to limit weight transfer under acceleration, and a big rear wing could let you get away with more rear spring rate.  The car would be looser at low speeds, but much more manageable through a high-speed slalom.



It might be worth talking to Andrew Cordeiro and his brother about the Scirocco they ran in E-Mod this year.  I think that car was 4th after the first day.

Rearward weight transfer under accel is the same, stiff springs or soft. CG height, wheelbase, and rate of acceleration are all that matters.

The longer the wheelbase, the more power you can use. The more static front weight, the more power you can use. A 100+ inch wheelbase is going to be necessary, and I probably wouldn't exceed 63-64% static front weight distribution. 250whp properly geared, is probably the "sweet spot". More power could occasionally be used, but you'd have diminishing returns. As much front tire as you can possibly fit to keep the tires from burning off the car. You won't need anything more then a 205 on the rear of the car because it isn't carrying much weight at all. Of course, all IMO, YMMV, my .02, etc.
 

Harold Knoble's DM Mini is a better example.  The car's trophied a number of times in DM, including 2nd this year.  Low CG, short wheelbase, good but not amazing power.  I like the long wheelbase idea, but it's just not practical since all the small lighweight fwd cars have short wheelbase.  I still think I'd run 225/13s in the rear, due to less inertia, as long as the ABS wouldn't get confused with the large diameter differences.
 

---

Jesse
-2002-2006 E-stock 93 MR2 (sold)
-2007-2008 XP Spyder

Yeah, the small, light fwd cars do tend to have short wheelbases. The 5th gen civic is one of the longer ones I know of at 102" or something like that. I don't know of any others that are that long. It'll be interesting to see how Chris does with his new car.

---

Nate Whipple
NER
188/88 DSP ITR

Robert Puertas:

It might be worth talking to Andrew Cordeiro and his brother about the Scirocco they ran in E-Mod this year.  I think that car was 4th after the first day.

 I chat with Andrew on a regular basis, and yes, he was 4th at Nat's after the first day this year, and there was a good chance they would have trophied, had they not forgotten to chech their wheel bearings before going, and having them both fail on the first run of the second day. He said there was an approximate 4-5* of extra toe out . Their car was putting down 186whp and about 160wtq, but they have something new in the works for this season. Let's just say that it isn't the first engine ANYONE would pick for an ultra-lightweight FWD car, but it should make the car very interesting to watch. Keep an eye out for the Cordeiro's in '08.

 Oh, and from what I've gathered from Andrew, on R-comps, about 270whp and 240wtq would be the MAXIMUM (possibly a little too much) power that a FWD car could use.

---

'77 Scirocco FWD SM Monster

BrianGT:

On a side note, I am damn curious what a 200+ hp well setup FWD car on 275/225 hoosiers would be like to drive :)

 -Brian

 it's fun... :)

Robert Puertas:

You're going to want the rear pretty stiff to limit weight transfer under acceleration, and a big rear wing could let you get away with more rear spring rate.  

i would never consider a rear wing on a fwd car, not needed. 

solo-x:

 The 5th gen civic is one of the longer ones I know of at 102" or something like that. I don't know of any others that are that long. 

i am shocked you didn't know the 5th gen hatch wheelbase nate... it is 101". the 5th gen coupe/sedan and 6th gen all are 103". the 88 hatch is 97"

Boise77Scirocco:

 from what I've gathered from Andrew, on R-comps, about 270whp and 240wtq would be the MAXIMUM (possibly a little too much) power that a FWD car could use.

nice numbers. what does that car weigh? 

---

Hi! I'm Rodney. "Hi Rodney!" I'm addicted to Solo....

Bah, I couldn't remember which was which, being that I had both. I knew it was 101 or 103, so a split the difference.

---

Nate Whipple
NER
188/88 DSP ITR

Boise77Scirocco:

Oh, and from what I've gathered from Andrew, on R-comps, about 270whp and 240wtq would be the MAXIMUM (possibly a little too much) power that a FWD car could use.

Meh...Andrew's a great guy and all, and has obviously been pretty successful with <200whp, but I'm not aware of any work he's done trying to drive an FWD car with 270+hp.

I agree very strongly with what Jesse (129STS) has said thus far. There was a time when my 235whp simply involved smoke everywhere. However, as Jesse mentioned already, I was pleasantly surprised with how  much longitudinal grip I was able to create by the end of the '06 season. I think I could effectively utilize at least 275whp, if not more. And that's with the 225-45/13s, which as Jesse also mentioned overheated VERY quickly at my power levels. Add 2" of tire, and you'll need another huge amount of whp to turn them.

My biggest problems were lateral grip, suspension geometry, and weight distribution. There are other FWD cars like Rodney's Civic with at least somewhat better DNA than the Scirocco in at least two of those areas, but I still think FWD gets the shaft under the SM rules. Too bad, since they're a heck of a lot cheaper to build. XP might allow for engineering around many of the issues, but A similarly prepped Miata would only be something like 100lbs heavier, IIRC. I still don't think there is enough of a weight break to make FWD really viable...or at least not viable enough to risk spending that much money and time but still have nothing more than an uncompetitive polished turd (even though I really love to drive my little car).

Neal

(still missing the ability to tune, turn knobs, and tweak his car, but not wealthy enough to build a competitive SM car   )
 

---

Team One Out

Borrowed 2004 Mazda RX-8
Solo B-Stock

Andrew??!!?!? :D:D:D

 Plans for this year are no secret.

2008 Jetta TDI Cup.

*fingers crossed*

 

EEK!

 

That's 300 Ft. Lbs. in a FWD car!  (and 170 hp)

 

But it's road-racing speeds... and a spec series... and the cost of front tires is included in the entry fee...
Looks like a great series... best of luck!

 

 

---

CARPE CURSUS = Seize the Race Track (latin)

http://www.hotbits.ca - Hot Bits Sport Suspensions
http://specclutch.com/ - Shift to a Higher Standard
http://www.twmperformance.com/ - Best short shifters and shift knobs available

StrokerAce:

MORE!!!!! To much is barely enough.

While I do agree with that.....I'd say about 200 to the wheels would be a good place to start.  Once you get past that, on Honda's anyway, you have to start thinking about upgrading the diff, and any power adders beyond that will requie some serious thinking and engine packaging, priced accordingly of course.

dyingwish:

StrokerAce:

MORE!!!!! To much is barely enough.

While I do agree with that.....I'd say about 200 to the wheels would be a good place to start.  Once you get past that, on Honda's anyway, you have to start thinking about upgrading the diff, and any power adders beyond that will requie some serious thinking and engine packaging, priced accordingly of course.

If you're building an SM car, you would already be upgrading the diff.  And on a Honda, Raxles makes whatever you need to hold whatever power you'll be making.  I would say to START with 250 whp with the smoothest powerband you can get.  Having the car go from 100 hp to 250 hp in 500 rpm will be awful.  *Cough* 2.0L or blown 1.6L*cough*
 

---

Jesse
-2002-2006 E-stock 93 MR2 (sold)
-2007-2008 XP Spyder