Choosing Right Manufacturer - Long Question - Page 3

TimOz40 · 08-10-05, 06:22 PM

Colin Chapman:
"power makes you fast on the straight, lightness makes you fast everywhere....."
Can't argue with that!

Mark Scrivener · 08-31-05, 03:39 AM

Great thread. My $0.02 from my days racing 250 GP bikes (225 lbs wet, 90 HP - even with the rider that is 4 lbs/pony):

There were a few series which allowed unlimited mods - Formula USA (WERA - ran at Willow among others) and Formula Pacific (AFM - ran at Sears Point). Some fast riders would bring bored out 750's with Nitro, Turbos, you name it. Others like me entered our 250's.

I remember one race at Willow (certainly a HP track) where this guy in a big HP bike had prob 20-30mph on me in the main straight. He would blow by me half way down the straight - and I would pass him braking for turn 1 while I was still shifting up another gear. It took a little work on my part, but he was soon way behind me. Sure he was faster on the middle of the straight - but I was faster every where else - including coming out of the turns (since I carried more speed through the turn).

As the track gets tighter (or you get faster) there is no longer any such thing as a straight. Sears was like this for me at one point - one giant turn. Bottom line - weight rules, light is right.

BTW - the 250 was a great bike which rewarded proper ridding - if you kept the momentum up and the revs up it rewarded you with insane lap times. Let the revs drop or lose momentum and you were toast. Unfortunately bike racing ruined my driving as trail braking was the way to go fast on a bike.

-Mark

Bill Musarra · 08-31-05, 10:02 AM

Wasn't it the Indy guys that were complaining about Dana Fitzpatrick being up to 100# lighter than most of the guys driving and should be penalized??? [img]/ubbthreads/images/graemlins/smirk.gif[/img] [img]/ubbthreads/images/graemlins/smirk.gif[/img] [img]/ubbthreads/images/graemlins/smirk.gif[/img]

Bill

Ron Earp · 08-31-05, 10:19 AM

Bill, yep, and that set me off. They knew the rules before coming to the race, long in advance. Jockeys are small for a reason, ditto motorcycle riders.

Some series, such as the SCCA stuff I do, is weight of car and driver at a minimum. So, that sort of equalizes, to a point. For example, in our upcoming 13 hour enduro we will set the weight of the car and driver to match the 227lb heavy driver, who will be last across the scales for impound. The rest of us, at around 155-165, will race at a nice advantage throughout the event, and you can tell 75lbs on a race car for sure!

But those Indy rules were weight of the car, period, so naturally it would benefit you to get as light of a driver as possible. I suppose the "large" racers have been disenfranchised? I've a suggestion: If those fellows were worried about competitors having an advantage maybe they should have done a little "training" and had a few less Big Macs or pushed back from the table a little earlier. I can't remember that one fellow that was on TV complaining but his head was as large as a beach ball and you could tell he'd been doing some eating! ;-)

Steve Toner · 08-31-05, 10:56 AM

Danica Patrick.

Dan Weilacher · 08-31-05, 08:08 PM

Also a few years back in CART the same thing came up with Da Matta weighing about 40 lbs less than most others. The rest of the guys were fit as well just taller and a larger frame. I think its a issue that should be adressed in all top motorsports.

JOSEPH · 08-31-05, 09:04 PM

Sandy, As for the G50 not being strong enough for 600 HP my neighbor down the street has a 1996 Porsche that he had the engine redone in Phoenix. It has twin turbos with a key switch for 5 lbs., 10 lbs. and 15 lbs. of boost. It dynoed at a little over 660 HP and it is an animal. He drives it like a drag racer all the time and has never had any trouble with the G50. And he has tires as wide as my CAV. He was forced to do that to his Porsche because his wife bought a M-55 Mercedes with 489 HP. Joseph

Sandy · 08-31-05, 10:22 PM

The thread that would not die [img]/ubbthreads/images/graemlins/laugh.gif[/img]

A G505X box from what I understand is pretty good, but not as strong as a simillarly prepped 930 box, so just went that route. I'm expecting either would have worked (Same for the ZF), just rather have the beefer of the 2. One thing that was also a decision point was that 930 boxes are much easier to get and less costly when preped. My choices were ultimatly the 930 or an NLT, both at opposites ends of the cost/hassle scale. I used the $$ difference to apply to other parts of the car, so worked out well.

For the power to weight ratio comments agreed! Nothing has ever scared me worse then my old Kawasaki 500 triple. Sold immediatly after a few rides, and would have like to apply the corvair slogan... "Unsafe at any speed" to it.

The HP is weight free for the most part these days, i.e., the weight diff between 289ci vs a 347ci (or 351ci to 427ci) is marginal so not as much a factor as it used to be from the engine perspective. I just want my GT40 to have a healthy motor (Subjective I guess...) from the start, and when I pump the rods out the side it likely will be time for the hp introspection!

Good discussion!

Sandy

Lynn · 09-01-05, 02:22 PM

Sandy,

I think you made good choices all around. I think you will find that working with Fran is going to be great; I have developed a lot of admiration for him in a relatively short period of time. Motor sounds very similar to what I am building, but I do envy you the aluminum block (my skinflint side, from being raised by an okie, just wouldn't let me pop for the extra bucks; wife and a kid 3 years from college also came into play :-) 930 transaxles are tank-like and gearing options should be more readily available and cheaper. BUT, you may want to keep your eyes open for a G50/50. I think they are the strongest transaxle Porsche ever put in a production vehicle. It took me a year and a half to find the right one, but it can be done. I think you'll find the extra gear and the hydraulic clutch well worth the hunt and, in the meantime, have a blast flogging the 930!

Comment on comments on tire size: I will use my car for more street than track, so I was looking for large diameter, vs width, because of the relatively low gearing of the transaxles in use. I have used modern low profile 17" tires, so while my car doesn't look "authentic", I have been able to get my REAL final drive ratio where I want it without the weight (unsprung I may add) penalty incurred with period looking, higher profile tires. Also, I have had several comments about how level looking my car is, which is not something I worked at, it just turned out that way.

Regards,
Lynn

Sandy · 09-01-05, 06:47 PM

I have seen only a few 505x for sale, they go quick, and they seem to be more then the cost of a new ZF and still need a build. Availability was the big problem. The 930 that Fran has hooked me up with will have 3rd and 4th gear ratios something like 1 and .83 for the final (I think orig 930 ratios are .894-3 and .625-4). The 930's really seem like the way to go unless you really want the extra gears. The choices were based on the fact that I really don't plan on going 200 mph, so I think with the Kumho V710's 345's on a 17" rim (26" dia) winds out to about 180mph which is fine for me.

The aluminum block is a simple but expensive way to loose 50 or so lbs (23kg). The trick in getting the Aluminum block is to not tell your wife, and have them charge it up on a secret auto parts credit card and confess later that you had it (and the balance on the card) before you were married :-) Second tip is have it delivered UPS to your work! If you do get caught, get the 'secret I blew it with my wife' credit card and make appropriate adjustments to her jewerly collection.

Yes the tire size (15 vs 17) make quite a different looking car and definitly each has to be 'height' adjust for best look unless you get lucky and it is right out of the box. I was almost thinking of geting a set of 15" rims for the more vintage look but the rear wide tire choices are very limiting so I agree on the 17" size plan for sure.

Sandy

Gary Gibbs · 09-02-05, 12:36 AM

Dart block is almost 100 lbs difference between Alum and Iron.

Sandy · 09-02-05, 05:27 AM

Here are the numbers, 100 lbs seemed a lot but then I forgot that might have been for the 9.5 deck block, and it is right about that. I didn't find much info on the regular 2 Bolt Ford castings, probabally not too far off, maybe lighter then 4 bolt irons.

Dart Aluminum Block 8.2" deck 83 lbs
Dart Iron Block 8.2" deck 160 lbs
M-6010-F302 SVO Aluminum 8.2 deck block 92 Lbs

Dart Aluminum Block 9.5" deck 93lbs
Dart Iron Block 9.5" deck 195 lbs

I can say this you can carry the cardboard box with the SVO just long enough to hide it into the garage :-)

Ron - Might be good for a specs section, i.e., weights, dimensions, etc.

Sandy

DerekW · 09-02-05, 07:13 PM

This thread gets nearest to where I'm at - trying to decide what to fit into my CAV r/chassis. I liked the idea of a 427 with 5 speed ZF because apparantly, although a bit taller than a 302, is not so wide making more space for exhausts. But then I heard that while the ZF can handle the bhp it might not handle to torque ? But PI and 2G and others seem to have made it work fine.

Then again John/Jean CAV website recommends around 400bhp stroked 302, as does ian at the CAV Canada website, and I guess it gives a bit less weight.

I'm likely to go for the ZF 5 speed because this seems to be nearest to the 60's spec, and seems the most reliable choice for the $$$. Can anybody help me make a rational choice between a 427 and a 347 ?

Sandy · 09-02-05, 07:35 PM

I'll assume 427 is a small block...

I talked to Roy at VIP and he has a 427Windsor in his CAV as also his mentioned friends. Would really have to as some CAVers about that.

To me I like the high rpm motors, so a 347'ish motor is what I went with. I have a 331 in my mustang that makes about 570@7200 and it would be undriveable on the street for the most part. Doing a 427w lets you make crazy hp all within the relm of running on pump gas. Check out keith craft's site for various combinations you can get a good feel for hp and some of the sizes of motors. Skip any of the 15:1 compression motors :-)

I also talked to a fellow at Pi (or is Pii) the pantera folks that had built a couple of CAV's with small block 427's and the ZF and they really seemed to think it was not a problem at all. They said they do higher hp stuff in some of the pantera's and have had very little trouble with the ZF.

The bigest factor seems to be what the car is used for, and how hard you drive it.

Do a search on the site and you should find many discussions on the transaxle's used in many of the cars.

Sandy