Read the new Fastracks and came upon the weight changes for HP. The VW's are now 185 lbs. lighter, so my inquiry follows. Is it possible to build a front running national HP VW, or is this a bone from the CRB? If the British roadsters get approximately 100 hp from their motors as a rule of thumb, they are working with a wgt/hp ratio of roughly 14:1. Is it possible to build a legal limited prep VW 1.6 capable of putting out a reliable 125 or more hp?
HP VW's
- Thread starter Grumpa
- Start date
Bill Miller
New member
Grumpa,
I don't know if you've asked about this on the Prod board or not. Talk to Don Barack. They'vv'e got their car (Mk I Scirocco) running pretty well. Don seems to think he can get the rest of the weight out of the car. It's not going to be cheap, but he thinks it can be done.
125hp is probably a stretch w/ the small valves and an unported head, but 115-120 should be possible. Again, not going to be cheap. Talk to David Boles, I believe he had an extra head w/ his cam in it, for sale. Talk to Walt Puckett about a header for the car.
I don't think (nor do several people I've spoken with) that the cars can really get any lighter than that. It would be easier to get ther if you're a 150 # driver.
------------------
MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608
I don't know if you've asked about this on the Prod board or not. Talk to Don Barack. They'vv'e got their car (Mk I Scirocco) running pretty well. Don seems to think he can get the rest of the weight out of the car. It's not going to be cheap, but he thinks it can be done.
125hp is probably a stretch w/ the small valves and an unported head, but 115-120 should be possible. Again, not going to be cheap. Talk to David Boles, I believe he had an extra head w/ his cam in it, for sale. Talk to Walt Puckett about a header for the car.
I don't think (nor do several people I've spoken with) that the cars can really get any lighter than that. It would be easier to get ther if you're a 150 # driver.
------------------
MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608
racer_tim
New member
We all know what "bricks" the Rabbit is, so the better alternative would be to build a LP HP Scirocco.
My GP Rabbit GTI now can weigh 1,965 lbs. There is NO way I can down to that weight without going with Lexan windows all the way around, and fiberglass fenders, hood, rear hatch, etc.
Like Bill said, it's doable, but it's going to be expensive.
Personally, I don't think that a LP VW will win any National Championships for a couple of years, or until it RAINS at the Run-Offs.
The funny thing, is that the LP british cars are already competitive, but they don't really want the LP tin tops to gain too much, too soon. I see the logic in this, since the open roadsters were the backbone of the production classes, but not any more.
As long as we keep trying, and keep on showing them that the VW community has the partitication numbers to show that we're not just a "flash in the pan" that we'll get more support and adjustments down the road.
Taking off weight is the easiest thing to give. After that, then we can ask for more compression, valve lift, etc.
I think that the 1.6 motor with the .450" valve lift will always be a better choice than the 1.8 with the 0.420" lift.
I'm just not ready do throw away my good, reliable 1.8 motor and build up one of my older 1.6's and go back to solid rotors.
Anybody need a ex ITC 75 Scirocco with a Quaife?
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html
[This message has been edited by racer_tim (edited December 12, 2004).]
[This message has been edited by racer_tim (edited December 12, 2004).]
My GP Rabbit GTI now can weigh 1,965 lbs. There is NO way I can down to that weight without going with Lexan windows all the way around, and fiberglass fenders, hood, rear hatch, etc.
Like Bill said, it's doable, but it's going to be expensive.
Personally, I don't think that a LP VW will win any National Championships for a couple of years, or until it RAINS at the Run-Offs.
The funny thing, is that the LP british cars are already competitive, but they don't really want the LP tin tops to gain too much, too soon. I see the logic in this, since the open roadsters were the backbone of the production classes, but not any more.
As long as we keep trying, and keep on showing them that the VW community has the partitication numbers to show that we're not just a "flash in the pan" that we'll get more support and adjustments down the road.
Taking off weight is the easiest thing to give. After that, then we can ask for more compression, valve lift, etc.
I think that the 1.6 motor with the .450" valve lift will always be a better choice than the 1.8 with the 0.420" lift.
I'm just not ready do throw away my good, reliable 1.8 motor and build up one of my older 1.6's and go back to solid rotors.
Anybody need a ex ITC 75 Scirocco with a Quaife?
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html
[This message has been edited by racer_tim (edited December 12, 2004).]
[This message has been edited by racer_tim (edited December 12, 2004).]
Tim,
I don't think it will be too long before a VW wins. I think Don will be in the top 2 next year just a hunch but he will be up front.
As for the weight I know my rabbit was almost down that low with the stock glass and steel fenders, granted I weigh 135lbs but I still think it is fairly easy and won't be too difficult. I am building a Scirocco right now and I think i can make it even lighter than my rabbit just by taking all the undercoating crap off the bottom which was not done on my rabbit. I'll let you know when i get her finished.
------------------
Sam Rolfe
TBR Motorsports
#85 ITC VW Rabbit being converted to LPHP
#85 GP Scirocco
I don't think it will be too long before a VW wins. I think Don will be in the top 2 next year just a hunch but he will be up front.
As for the weight I know my rabbit was almost down that low with the stock glass and steel fenders, granted I weigh 135lbs but I still think it is fairly easy and won't be too difficult. I am building a Scirocco right now and I think i can make it even lighter than my rabbit just by taking all the undercoating crap off the bottom which was not done on my rabbit. I'll let you know when i get her finished.
------------------
Sam Rolfe
TBR Motorsports
#85 ITC VW Rabbit being converted to LPHP
#85 GP Scirocco
racer_tim
New member
Sam, I'm spotting you 100 lbs right off the bat.
I too could remove more of the undercoating, but then it might rust. In California? I don't think so. hehehe
I watched the GP race this weekend, and it was too bad that Chuck got taken out by Jef Winter.
Chuck's a full prep car, just like Mr. Coffin's but Chris Albin and Brian Culbertson are both in LP VW's.
Good luck in 05
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html
I too could remove more of the undercoating, but then it might rust. In California? I don't think so. hehehe
I watched the GP race this weekend, and it was too bad that Chuck got taken out by Jef Winter.
Chuck's a full prep car, just like Mr. Coffin's but Chris Albin and Brian Culbertson are both in LP VW's.
Good luck in 05
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html
My car is a '79 ITC Rabbit that is way behind development wise. No camber plates, old Neuspeed sport springs and shocks, an unported head, Toyo RA1's on steel wheels, open differential, 1.5L, etc. ad infinitum. I did an open track day at Putnam Park and got the car down to a 1:30.4, but the SCCA has not raced there for several years so I can't compare time. NASA runs there, but the only car that I could compare to was a Honda Civic that ran H5 and I don't know if the two cars would match up.
I bought the car to get experience and with the idea of building it into a regional HP car when finances allow. I recognize the limitations of the car's technology, but I also see a number of VW's that are well prepared and well driven at the IT level. Is building a competitive LP H Production VW a quantum leap in terms of knowledge and money? I am sure that on a National level it has to be, in order to keep pace with the British roadsters. Perhaps I am just naive, but comparing the adjusted weights in the class, it seemed to me that the hp 2 wgt ratio got better in terms of the VW horsepower gap. I recognize that the Rabbit is a brick in terms of aerodynamics, but is a Scirocco so aero superior to a Rabbit that it would be a waste of resources to attempt to LPHP a Bunny? Thanks for entertaining this Newbie. Merry Christmas, and God bless all the VW racers.
I bought the car to get experience and with the idea of building it into a regional HP car when finances allow. I recognize the limitations of the car's technology, but I also see a number of VW's that are well prepared and well driven at the IT level. Is building a competitive LP H Production VW a quantum leap in terms of knowledge and money? I am sure that on a National level it has to be, in order to keep pace with the British roadsters. Perhaps I am just naive, but comparing the adjusted weights in the class, it seemed to me that the hp 2 wgt ratio got better in terms of the VW horsepower gap. I recognize that the Rabbit is a brick in terms of aerodynamics, but is a Scirocco so aero superior to a Rabbit that it would be a waste of resources to attempt to LPHP a Bunny? Thanks for entertaining this Newbie. Merry Christmas, and God bless all the VW racers.
Bill Miller
New member
I don't know if I'd say it was a waste of resources, but all else being equal (same prep level, same driver), a Scirocco should be faster than a Rabbit. Being as I think they're still a bit down to the Brit cars, I think you need to find every way possible to go faster, if you want a Runoffs' podium car.
------------------
MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608
------------------
MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608
racer_tim
New member
Grumpa, you've got lots of improvements to do to the car, whether you stay in ITC or you go to LP HP.
If you were to stay in IT, I'd invest in camber plates, coil-overs and good shocks/struts, wheels, LSD, and a decent port job on the head.
With that said, you'd most likely have to do the same if you were to convert to LP H Production. Camber plates aren't that important in production, since you run way less camber with slicks than with DOT tires.
You'd need to add a fire system and a fuel cell as a bare minimum to convert to production, but other than some minor things like glass, headlights, etc. there's not that much difference. A standard 8 point cage for IT is legal in Production, so if you only have a 6 point now, in Prod you can go "THROUGH" the firewall, so that would be a deciding factor which class you choose to go to.
In Production, you can increase the compression, and go with a hotter cam, but since you currently don't have a ported head, you'd be looking at $$$'s to increase the performance in either IT or Prod.
Anyway, it seems that your on the bottom part of the learning curve, and unless you want to win everything, keep the car the way it is, and just enjoy yourself being on the track.
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html
If you were to stay in IT, I'd invest in camber plates, coil-overs and good shocks/struts, wheels, LSD, and a decent port job on the head.
With that said, you'd most likely have to do the same if you were to convert to LP H Production. Camber plates aren't that important in production, since you run way less camber with slicks than with DOT tires.
You'd need to add a fire system and a fuel cell as a bare minimum to convert to production, but other than some minor things like glass, headlights, etc. there's not that much difference. A standard 8 point cage for IT is legal in Production, so if you only have a 6 point now, in Prod you can go "THROUGH" the firewall, so that would be a deciding factor which class you choose to go to.
In Production, you can increase the compression, and go with a hotter cam, but since you currently don't have a ported head, you'd be looking at $$$'s to increase the performance in either IT or Prod.
Anyway, it seems that your on the bottom part of the learning curve, and unless you want to win everything, keep the car the way it is, and just enjoy yourself being on the track.
------------------
Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit
http://linerud.myvnc.com/racing/index.html
racer14itc
New member
A Scirocco has about 15% less aero drag than a Rabbit. Aero drag = Cd X Frontal area. The Rabbit has about a 3" higher roof, which is the additional frontal area; and a poorer Coefficient of drag, Cd. I don't remember the exact numbers but I do remember the 15% aero drag figure.
(edit: I found the numbers:
Scirocco Cd = 0.38 Frontal area = 18.72 sq. ft. Aero drag = 7.11
Rabbit Cd = 0.42 Frontal area = 19.8 sq. ft. Aero drag = 8.28)
These numbers are probably only significant over 60-70 MPH on the track, so it depends on the track. Stu at BSI once told me that his ITC Sciroccos were about 5 MPH faster than his ITC Rabbits at Daytona. Having raced against ITC Rabbits with my ITC Scirocco I can give experiential data that confirms this. It was usually pretty easy to make passes on ITC Rabbits at the end of long straights, Just from the aero drag difference.
If I were to build any sort of production VW from scratch it would definitely be a Scirocco, since the minimum weights are the same for the Sciroccos and Rabbits. The above discussion doesn't even take into account the lower CG of the Scirocco. You put a roll cage to the roof, which you are required to do, and all that roof tubing is 3" higher in a Rabbit than in a Scirocco.
MC
------------------
Mark Coffin
#14 GP BSI Racing/Airborn Coatings/Krispy Kreme/Tristram's Garage VW Scirocco
http://pages.prodigy.net/Scirocco14gp
[This message has been edited by racer14itc (edited December 14, 2004).]
(edit: I found the numbers:
Scirocco Cd = 0.38 Frontal area = 18.72 sq. ft. Aero drag = 7.11
Rabbit Cd = 0.42 Frontal area = 19.8 sq. ft. Aero drag = 8.28)
These numbers are probably only significant over 60-70 MPH on the track, so it depends on the track. Stu at BSI once told me that his ITC Sciroccos were about 5 MPH faster than his ITC Rabbits at Daytona. Having raced against ITC Rabbits with my ITC Scirocco I can give experiential data that confirms this. It was usually pretty easy to make passes on ITC Rabbits at the end of long straights, Just from the aero drag difference.
If I were to build any sort of production VW from scratch it would definitely be a Scirocco, since the minimum weights are the same for the Sciroccos and Rabbits. The above discussion doesn't even take into account the lower CG of the Scirocco. You put a roll cage to the roof, which you are required to do, and all that roof tubing is 3" higher in a Rabbit than in a Scirocco.
MC
------------------
Mark Coffin
#14 GP BSI Racing/Airborn Coatings/Krispy Kreme/Tristram's Garage VW Scirocco
http://pages.prodigy.net/Scirocco14gp
[This message has been edited by racer14itc (edited December 14, 2004).]
m glassburner
New member
Hmmmm get rid of the windshield(convertable)...now what's the drag??? Of course more bars to stiffen the chassis
[This message has been edited by m glassburner (edited December 14, 2004).]
[This message has been edited by m glassburner (edited December 14, 2004).]
racer14itc
New member
Originally posted by m glassburner:
Hmmmm get rid of the windshield(convertable)...now what's the drag??? Of course more bars to stiffen the chassis
[This message has been edited by m glassburner (edited December 14, 2004).]
The cabriolet does have a 100 lb weight penalty across the board in production (GP and HP). 100 lbs usually translates into about a second a lap. Can the reduced aero make up a second a lap? That's the question.
Dump the MOPAR stuff Mike and come over to the dark side!!
NO, wait, on second thought stay in IT...
MC
------------------
Mark Coffin
#14 GP BSI Racing/Airborn Coatings/Krispy Kreme/Tristram's Garage VW Scirocco
http://pages.prodigy.net/Scirocco14gp
racer14itc
New member
Originally posted by racer14itc:
The cabriolet does have a 100 lb weight penalty across the board in production (GP and HP). 100 lbs usually translates into about a second a lap. Can the reduced aero make up a second a lap? That's the question.
Dump the MOPAR stuff Mike and come over to the dark side!!You already know how to make a FWD car go fast and can drive to boot. You'd be VERY competitive in a prod VW I'm sure.
NO, wait, on second thought stay in IT...I'm tired of chasing fast former FWD IT drivers in G prod: Albin, Mathis, Deatherage, Griffin, Hulse...
My nightmare is the Blethen boys decide to race in prod.Luckily there aren't any Audis in prod (yet).
MC
OOops..pressed the wrong button.
You get the idea...
------------------
Mark Coffin
#14 GP BSI Racing/Airborn Coatings/Krispy Kreme/Tristram's Garage VW Scirocco
http://pages.prodigy.net/Scirocco14gp
[This message has been edited by racer14itc (edited December 14, 2004).]
racer14itc
New member
The answer to your question is Yes, it is possible. Find the right head, do the right prep (head, crank lightening/polishing/knife edging, rods, crank scrapers/sump), the right camshaft, work on the exhaust system and you can legally make 125+ (and I emphasize the plus...) hp.
MC
------------------
Mark Coffin
#14 GP BSI Racing/Airborn Coatings/Krispy Kreme/Tristram's Garage VW Scirocco
http://pages.prodigy.net/Scirocco14gp
[This message has been edited by racer14itc (edited December 14, 2004).]
m glassburner
New member
You know it's funny you should mention that I got my start in SCCA racing driving a GT -3 daytona FWD delivering about 215 hp it was a blast once I got used to the slicks
p.s. one of the first cars I ever owned was a VW rabbit deisel not fast but cornered well...
Tom A
New member
Bringing this thread back from the dead, my A1 GTI has a SCCA Logbook (last annual was in 2003, IIRC) for ITB, but isn't legal, due to removal of some ITB mandated "stuff", like HVAC, turn signal stalks, etc, plus a "G" grind cam. Except for the cam, the engine is ITB legal. I am considering converting the car to G-Prod (limited prep) or F-Prod. Looking at the GCR, and reading past posts, it looks like what I would be required to do is:
Fire system
Fuel Cell
Remove headlights & side markers
Windshield clips/strap
Remove door glass and mechanisms
Ensure the cage extends to the firewall
Anything I am missing?
An old thread says that Production classed cars are required to run leaded race gas, but I don't see any mention of this in the current GCR. All I see is that "Permitted Fuel is herein defined as Gasoline" with some tests the fuel must pass, which frankly I don't understand. I don't plan on doing anything to my engine at this point that would require anything higher than 91 Octane pump gas, and Leaded fuel will damage my O2 sensor. Is this somethan that has changed, or is there a leaded fuel requirement some other place I can't find?
What is involved in changing the class of a car? If the logbook says ITB, do I have to get a new logbook, or can it just be updated at an annual?
I realize the "G" grind cam has too much lift for limited prep.
Thanks,
Tom
Fire system
Fuel Cell
Remove headlights & side markers
Windshield clips/strap
Remove door glass and mechanisms
Ensure the cage extends to the firewall
Anything I am missing?
An old thread says that Production classed cars are required to run leaded race gas, but I don't see any mention of this in the current GCR. All I see is that "Permitted Fuel is herein defined as Gasoline" with some tests the fuel must pass, which frankly I don't understand. I don't plan on doing anything to my engine at this point that would require anything higher than 91 Octane pump gas, and Leaded fuel will damage my O2 sensor. Is this somethan that has changed, or is there a leaded fuel requirement some other place I can't find?
What is involved in changing the class of a car? If the logbook says ITB, do I have to get a new logbook, or can it just be updated at an annual?
I realize the "G" grind cam has too much lift for limited prep.
Thanks,
Tom
Bill Miller
New member
Tom,
As Jeff said, you'll probably get more info on the Prod board.
Here's the link.
http://www.coloradoscca.org/prodcar/index.php
AFAIK, you can keep the original logbook. There are several guys on the Prod site have converted IT cars, I'm sure one of them can give you a definitive answer.
As Jeff said, you'll probably get more info on the Prod board.
Here's the link.
http://www.coloradoscca.org/prodcar/index.php
AFAIK, you can keep the original logbook. There are several guys on the Prod site have converted IT cars, I'm sure one of them can give you a definitive answer.
Greg Gauper
New member
As somebody who has crossed over to the dark side from IT 
Your 'conversion' list is pretty complete. The only other item you might need is a scatter shield for the clutch/flywheel. See GCR section 17.25 to determine if your prod car requires a shield.
Regarding fuel, the only requirement is to run a race gas with a DC of 0.0 or less. Most (but not all!) unleaded fuels have a slightly positive DC. A cheap alternative that does pass the SCCA fuel test is 100 Octane Low Lead AVgas. This is a popular fuel for FF/FC/FV/S2000 who also must use 'race fuel' but have low compression motors. There has been a lot of discussion over on the FF/FC website regarding this fuel. Even 7-time champ Weitzenhof runs AVgas until he gets to the big show. While it has some lead, it is less than normal race gas so you might get more life out of your sensor with it.
I've been told that even if you do run leaded fuel, you can probably get a season out of the O2 sensor before you have to change it.
If you can find an unleaded fuel with a DC of 0.0 or less, that also passes the reagent tests, it is legal for Prod.
Your 'conversion' list is pretty complete. The only other item you might need is a scatter shield for the clutch/flywheel. See GCR section 17.25 to determine if your prod car requires a shield.Regarding fuel, the only requirement is to run a race gas with a DC of 0.0 or less. Most (but not all!) unleaded fuels have a slightly positive DC. A cheap alternative that does pass the SCCA fuel test is 100 Octane Low Lead AVgas. This is a popular fuel for FF/FC/FV/S2000 who also must use 'race fuel' but have low compression motors. There has been a lot of discussion over on the FF/FC website regarding this fuel. Even 7-time champ Weitzenhof runs AVgas until he gets to the big show. While it has some lead, it is less than normal race gas so you might get more life out of your sensor with it.
I've been told that even if you do run leaded fuel, you can probably get a season out of the O2 sensor before you have to change it.
If you can find an unleaded fuel with a DC of 0.0 or less, that also passes the reagent tests, it is legal for Prod.