My STR Carrera 3.2 Build
10-08-2012, 01:33 PM
#1
Burning Brakes
Thread Starter
My STR Carrera 3.2 Build
UPDATE: Blog at http://strcarrera.blogspot.com/
Hi all, there are a few threads about theoretically building a 3.2 Carrera for SCCA STR autocross, but I can't find anything about someone actually doing it.
The S2000 and NC Miata guys have great build threads that take a lot of guesswork out of the deal, my hope is that one day this could be a sort of "template" for anyone else who decides to go down this road.
Probably like most of you, since I was a very young child I have wanted a 911. I had the good fortune to be able to pick one up in great condition for a very good deal. Here is the car:
It's a 1984 Carrera sunroof coupe. Only a few option codes on the sticker, pretty basic model. I haven't dug around on the car too much to know what is not OEM, but for sure it's quite low and has the 17" wheels.
My goal is to slowly prepare it for SCCA Street Touring R class, a relatively new class, where the Honda S2000 and NC Miata currently rule the roost. I may be bringing a knife to a gunfight, but I try to rationalize it as the car is lighter than the S2000 and narrower than the NC, with the shortest wheelbase, and a good bit more torque down low than either of them. I'm not doing a no-holds-barred build, just looking to get a competent "sportsman" level car out of the deal I can use locally for a long, long time. I'm no brilliant driver, but an attainable goal would be able to PAX in the top 10% or so at local events.
Hi all, there are a few threads about theoretically building a 3.2 Carrera for SCCA STR autocross, but I can't find anything about someone actually doing it.
The S2000 and NC Miata guys have great build threads that take a lot of guesswork out of the deal, my hope is that one day this could be a sort of "template" for anyone else who decides to go down this road.
Probably like most of you, since I was a very young child I have wanted a 911. I had the good fortune to be able to pick one up in great condition for a very good deal. Here is the car:
It's a 1984 Carrera sunroof coupe. Only a few option codes on the sticker, pretty basic model. I haven't dug around on the car too much to know what is not OEM, but for sure it's quite low and has the 17" wheels.
My goal is to slowly prepare it for SCCA Street Touring R class, a relatively new class, where the Honda S2000 and NC Miata currently rule the roost. I may be bringing a knife to a gunfight, but I try to rationalize it as the car is lighter than the S2000 and narrower than the NC, with the shortest wheelbase, and a good bit more torque down low than either of them. I'm not doing a no-holds-barred build, just looking to get a competent "sportsman" level car out of the deal I can use locally for a long, long time. I'm no brilliant driver, but an attainable goal would be able to PAX in the top 10% or so at local events.
Last edited by burglar; 03-05-2013 at 06:19 PM.
10-08-2012, 01:53 PM
#2
Burning Brakes
Thread Starter
I've had a few weeks to familiarize myself with the car. I've had the valves adjusted during the post purchase inspection (wait, the first "p" stands for pre? Whoops.) I couldn't take the Carrera Lag, felt like German vtec, so I immediately put in a Steve Wong chip. Neat piece, great instructions, and made a noticeable difference right off the bat.
Yesterday was my first shakedown runs for the car. I haven't checked the alignment, and I took a guess on the tire pressures. I also ran the not ideal BFGs the PO had on there.
Video link:
That's not my fastest run, but I did put it sideways through the finish.
We had an event at a smallish lot that featured two 180° spin cones, my least favorite element of all time. Ah well. Car operated great all day. I was dreading the 1-2 shift, but neither myself or my co-driver botched it once, we went 10 for 10. The manual steering was only tough on the really slow bits, and even then it was manageable.
Right away I can tell you that the 205/255 combo isn't going to work. We spent a lot of time waiting for corners to be over. I also think the car is too low, as bump steer was distracting in several spots. I also have a feeling that we were bouncing it off the bumpstops, as there was some weird handling balance changes. The car never got into the powerband on the tight course, but the low end felt good.
For 15 years I've been trail braking and lifting at turn in to help cars rotate. Um, that's a bad idea in the 911. I have to learn to drive all over again.
Results: 1st in STR! Okay, there were only three cars. More telling is the 58th on PAX (out of 101.) Not good. My metric for performance is going to be percentage of top PAX - this event I went 87.4% as fast as the leader. Also not good, but hey, it's a shakedown run. Goal is to get up in the mid 90s.
Stay tuned, throw me ideas, and hopefully one day there will be hundreds of people viewing this thread building their very own version of one of the coolest cars ever made. I'll have plenty of questions coming, this is going to be a great learning experience.
Yesterday was my first shakedown runs for the car. I haven't checked the alignment, and I took a guess on the tire pressures. I also ran the not ideal BFGs the PO had on there.
Video link:
We had an event at a smallish lot that featured two 180° spin cones, my least favorite element of all time. Ah well. Car operated great all day. I was dreading the 1-2 shift, but neither myself or my co-driver botched it once, we went 10 for 10. The manual steering was only tough on the really slow bits, and even then it was manageable.
Right away I can tell you that the 205/255 combo isn't going to work. We spent a lot of time waiting for corners to be over. I also think the car is too low, as bump steer was distracting in several spots. I also have a feeling that we were bouncing it off the bumpstops, as there was some weird handling balance changes. The car never got into the powerband on the tight course, but the low end felt good.
For 15 years I've been trail braking and lifting at turn in to help cars rotate. Um, that's a bad idea in the 911. I have to learn to drive all over again.
Results: 1st in STR! Okay, there were only three cars. More telling is the 58th on PAX (out of 101.) Not good. My metric for performance is going to be percentage of top PAX - this event I went 87.4% as fast as the leader. Also not good, but hey, it's a shakedown run. Goal is to get up in the mid 90s.
Stay tuned, throw me ideas, and hopefully one day there will be hundreds of people viewing this thread building their very own version of one of the coolest cars ever made. I'll have plenty of questions coming, this is going to be a great learning experience.
10-09-2012, 11:06 PM
#3
Drifting
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Use the weight bias to your advantage when you can. Don't lift. Have fun. Repeat
10-10-2012, 07:31 PM
#4
Can I play?
Step 1, call DR-SCCA's very own Paul Eddelston & get a set of 15x8 & 15x9 these:
Step 2, spend the rest of the winter figuring out which tires to use.
edit -> http://www.braidusa.com/Wheels/Comp/BZ/BZ.htm
Step 1, call DR-SCCA's very own Paul Eddelston & get a set of 15x8 & 15x9 these:
Step 2, spend the rest of the winter figuring out which tires to use.
edit -> http://www.braidusa.com/Wheels/Comp/BZ/BZ.htm
Last edited by ToSi; 10-10-2012 at 07:48 PM.
10-11-2012, 01:36 PM
#5
Burning Brakes
Thread Starter
10-15-2012, 01:20 PM
#6
Burning Brakes
Thread Starter
2nd event and last of the season with the car.
This was a much bigger Nationals-style course, much higher speed, and transition happy. The car was a ball to drive. Played around a bit with using the lift-throttle oversteer to help the car rotate, it doesn't seem to like it, at least in it's current incarnation.
Did worse on my index points scale (84.6%) but in my defense the reigning A-Mod National Champion set the index.
Also, I ordered a part. Through-body swaybars are not STR legal, which limits my options. The stock Carrera front swaybar is supposedly 20mm. The 930 bar is 22mm. Addco part #827 is stock style and 7/8" (22.225mm) and under $150. Worth a shot. Search about it comes up empty on Rennlist.
The offseason begins now.
This was a much bigger Nationals-style course, much higher speed, and transition happy. The car was a ball to drive. Played around a bit with using the lift-throttle oversteer to help the car rotate, it doesn't seem to like it, at least in it's current incarnation.
Did worse on my index points scale (84.6%) but in my defense the reigning A-Mod National Champion set the index.
Also, I ordered a part. Through-body swaybars are not STR legal, which limits my options. The stock Carrera front swaybar is supposedly 20mm. The 930 bar is 22mm. Addco part #827 is stock style and 7/8" (22.225mm) and under $150. Worth a shot. Search about it comes up empty on Rennlist.
The offseason begins now.
10-15-2012, 03:22 PM
#7
Quit Smokin'
Rennlist Member
Rennlist Member
Keep in mind, opinions are like noses, so I hope you are not offended by my feedback, I certainly don't mean to be offensive.
It looks to me like you are throwing the car into transitions. You're basically asking the car to change directions while the chassis is still confused. My car absolutely loves a little bit of trail brake to set the front end, and also loves to be driven with the throttle. I find that one smooth input of the steering wheel is all you need most of the time, then you drive the car's attitude smoothly with the right pedal. Your hands actually look pretty good, so I think if you slowed down you first input (every corner) you could play with the throttle a lot more, and the car would be more enjoyable.
I've told my students that in autocross there are two types of action: -1 you ask the car to do something (bending it into a sweeper). -2 you TELL the car to do something, ie. you purposefully upset the car to cheat through a transition. In a 911 I very rarely TELL the car to do anything with the steering wheel. I ask with the wheel, and tell with the gas pedal. You still need fast hands for countersteering, because big chassis slip angles rob tons of speed (you can see this in several places in your video). Work on bending the car with the steering wheel, this may mean you need to start your turns slightly earlier to get the car set.
As for tire pressure, I start at 32F 34R cold and just let them build on street tires.
I wouldn't spend a bunch of money on fancy sway bars right off. My car is on stock bushings and stock sway bars, with big torsion bars and Koni shocks. I don't know the bar sizes off hand, sorry,
. Most people say it's sprung a little too stiff, but I LOVE it.
This is my '89 carrera based car in action:
It looks to me like you are throwing the car into transitions. You're basically asking the car to change directions while the chassis is still confused. My car absolutely loves a little bit of trail brake to set the front end, and also loves to be driven with the throttle. I find that one smooth input of the steering wheel is all you need most of the time, then you drive the car's attitude smoothly with the right pedal. Your hands actually look pretty good, so I think if you slowed down you first input (every corner) you could play with the throttle a lot more, and the car would be more enjoyable.
I've told my students that in autocross there are two types of action: -1 you ask the car to do something (bending it into a sweeper). -2 you TELL the car to do something, ie. you purposefully upset the car to cheat through a transition. In a 911 I very rarely TELL the car to do anything with the steering wheel. I ask with the wheel, and tell with the gas pedal. You still need fast hands for countersteering, because big chassis slip angles rob tons of speed (you can see this in several places in your video). Work on bending the car with the steering wheel, this may mean you need to start your turns slightly earlier to get the car set.
As for tire pressure, I start at 32F 34R cold and just let them build on street tires.
I wouldn't spend a bunch of money on fancy sway bars right off. My car is on stock bushings and stock sway bars, with big torsion bars and Koni shocks. I don't know the bar sizes off hand, sorry,
. Most people say it's sprung a little too stiff, but I LOVE it.This is my '89 carrera based car in action:
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10-15-2012, 03:51 PM
#8
Burning Brakes
Thread Starter
Thanks for your input.
I used yesterday to try out a few techniques to see what worked / didn't work. You said it a lot better than me, but I came to a similar conclusion on the car - it does not respond well to being overdriven.
Also, right now the car is taking a long time to take a set. I'm pretty sure it's on factory torsion bars and the original (!) struts.
I'm aware of my "pitch and catch" driving style. It has come from many years of actively trying to unsettle the rear of FWD cars. That's going to be a difficult tendency to deprogram, but ultimately I'm hoping the car can make me a better driver.
Your car looks great in action. I've never driven on an airport course like that before.
I used yesterday to try out a few techniques to see what worked / didn't work. You said it a lot better than me, but I came to a similar conclusion on the car - it does not respond well to being overdriven.
Also, right now the car is taking a long time to take a set. I'm pretty sure it's on factory torsion bars and the original (!) struts.
I'm aware of my "pitch and catch" driving style. It has come from many years of actively trying to unsettle the rear of FWD cars. That's going to be a difficult tendency to deprogram, but ultimately I'm hoping the car can make me a better driver.
Your car looks great in action. I've never driven on an airport course like that before.
10-15-2012, 07:44 PM
#9
Instructor
I would work on trying to make the wheel/tire setup as square as possible. I'm not sure if 255's all around will work, but to win STR you need to try.
Is that small lot where you always run? Shorter tires will help lower your gearing some.
I'd start some of the normal suspension mods. I'd recommended an adjustable front sway bar that could be used to balance your square tire setup.
Allen Skillicorn
Is that small lot where you always run? Shorter tires will help lower your gearing some.
I'd start some of the normal suspension mods. I'd recommended an adjustable front sway bar that could be used to balance your square tire setup.
Allen Skillicorn
10-15-2012, 09:39 PM
#10
Quit Smokin'
Rennlist Member
Rennlist Member
http://www.tirerack.com/tires/tires....=yes&tab=Specs
If you have a set of 16s I would do the RE11 in 225 / 245 stagger. If you only have 17s go with the Hankook RS3s and go wider.
Allen is right ideally, but I don't think you can pull on the fenders in STR and theres almost no way to get a 245 and up tire on the front. 225 / 245 will go on the car really nicely. Get your spring rates up and decent shocks and you'll be really surprised. If you're adept at tuning sways, by all means, get them, but I would start simple and work from there.
Is your second video taken at Toledo express airport? I was there running shifter karts at the pro this year. It's so grippy I pulled a rear tire off the bead during a slolom!
PS. damn this thread, I really really really want to try an STR 911 now.
If I mount up a set of RE11s on my 8&9 Fuchs, can I meet up with you for a codrive?? :P
If you have a set of 16s I would do the RE11 in 225 / 245 stagger. If you only have 17s go with the Hankook RS3s and go wider.
Allen is right ideally, but I don't think you can pull on the fenders in STR and theres almost no way to get a 245 and up tire on the front. 225 / 245 will go on the car really nicely. Get your spring rates up and decent shocks and you'll be really surprised. If you're adept at tuning sways, by all means, get them, but I would start simple and work from there.
Is your second video taken at Toledo express airport? I was there running shifter karts at the pro this year. It's so grippy I pulled a rear tire off the bead during a slolom!
PS. damn this thread, I really really really want to try an STR 911 now.
If I mount up a set of RE11s on my 8&9 Fuchs, can I meet up with you for a codrive?? :P
10-16-2012, 09:37 AM
#11
Burning Brakes
Thread Starter
Is your second video taken at Toledo express airport? I was there running shifter karts at the pro this year. It's so grippy I pulled a rear tire off the bead during a slolom!
PS. damn this thread, I really really really want to try an STR 911 now.
If I mount up a set of RE11s on my 8&9 Fuchs, can I meet up with you for a codrive?? :P
The whole point of this thread is to get people excited enough to build more STR 911s. My car (and the driver) will never be nationally competitive, but I'd love to see someone with more talent / knowledge / resources freak out a few S2000 owners with a 25+ year old car.
I'll have better tires on by next year - who knows, maybe the Dunlop ZII will be here by then - but you're welcome to co-drive. I've got a decent line forming already though. I couldn't give away co-drives in a PAX competitive Z, RX8, or Mini, but people go nuts over the completely unprepped (slow!) 911.
10-16-2012, 01:54 PM
#12
Three Wheelin'
http://www.tirerack.com/tires/tires....=yes&tab=Specs
If you have a set of 16s I would do the RE11 in 225 / 245 stagger...... 225 / 245 will go on the car really nicely........ :P
If you have a set of 16s I would do the RE11 in 225 / 245 stagger...... 225 / 245 will go on the car really nicely........ :P
10-16-2012, 11:01 PM
#13
Burning Brakes
Following this thread with interest.
When STR was formed I considered doing a 911 very strongly. I thought it would take $20K and car would have to get to 2550 lbs and 245 crank HP to match the Honda close enough to where the driver would make the difference. I assumed 225F (8") and 255 rear (9"), bespoke exhaust solution, etc. With so much rear weight bias, I didn't see the 225 in front as a hindrance. This was all spreadsheet calcs... I hadn't driven one! (So, tell me to shut up.) All this was to be nationally competitive in SCCA.
Your goals are not that high, but still, good luck and keep us posted.
PS: I've done a lot of street-tire auto crossing. Love the Yoko AD08, didn't care for the RS-3 (too temperature dependent) and had a lot of fun on Star Specs.
When STR was formed I considered doing a 911 very strongly. I thought it would take $20K and car would have to get to 2550 lbs and 245 crank HP to match the Honda close enough to where the driver would make the difference. I assumed 225F (8") and 255 rear (9"), bespoke exhaust solution, etc. With so much rear weight bias, I didn't see the 225 in front as a hindrance. This was all spreadsheet calcs... I hadn't driven one! (So, tell me to shut up.) All this was to be nationally competitive in SCCA.
Your goals are not that high, but still, good luck and keep us posted.
PS: I've done a lot of street-tire auto crossing. Love the Yoko AD08, didn't care for the RS-3 (too temperature dependent) and had a lot of fun on Star Specs.
10-17-2012, 04:12 PM
#14
Three Wheelin'
10-17-2012, 06:29 PM
#15
Quit Smokin'
Rennlist Member
Rennlist Member
Too weird, I have spent a lot of time running street tires at national events the past few years, and I have never heard anyone say anything good about the Yoko tire. I have the most time on the RE11 and the RS3. I've even had good luck with the RS3 in cooler temps, and in the wet. I guess having a codriver helps with the heat issue.
Seems like I see mostly Toyos and Hankooks these days, and these cars are probably way too heavy to work on the Toyo. May take some trial and error.
The McClintocks and Larry and Alan are probably some of the best people in this sport... and I don't just mean in the driver's seat. Mike McClintock put me in his Tony Kart for Nationals this year after I broke mine on the practice course. Talk about a well setup ride. Couldn't ask to run across nicer people!
Seems like I see mostly Toyos and Hankooks these days, and these cars are probably way too heavy to work on the Toyo. May take some trial and error.
The McClintocks and Larry and Alan are probably some of the best people in this sport... and I don't just mean in the driver's seat. Mike McClintock put me in his Tony Kart for Nationals this year after I broke mine on the practice course. Talk about a well setup ride. Couldn't ask to run across nicer people!