Back to SCCA 1972 rules?

[RHough]

Looking at the Porsche "Super 90"

capacity 1.6 litre 1582 cc
bore × stroke 82.5 × 74 mm
maximum power output
(net) 90.2 PS (89 bhp) (66.4 kW) at 5500 rpm
specific output
(net) 56.3 bhp/litre
maximum torque
(net) 121 Nm (89 ft·lb) (12.3 kgm) at 4300 rpm
specific torque
(net) 76.49 Nm/litre
compression ratio 9:1
2 Solex 40PJJ-4 carburettors

Is there any reason to think a VW 1584 can't make these numbers? 89 HP / 89 ft/lb / 56.3 BHP/Liter

That sounds just about like what I'm looking for.

R

[gearheadgreg]

What would it take to get 105-110 HP on the ground? 1776? 1915? bigger? Could a 1600 do it?

So, you wanted 105-110 to the ground before (say 130-140 at the crank), and now you are looking at 90 at the crank as your goal, or 65-70 at the ground? That's a fairly significant shift.

There's no reason a high-strung, big valve 1584 couldn't do that, but that's not what you said you wanted to do.

[RHough]

What would it take to get 105-110 HP on the ground? 1776? 1915? bigger? Could a 1600 do it?

So, you wanted 105-110 to the ground before (say 130-140 at the crank), and now you are looking at 90 at the crank as your goal, or 65-70 at the ground? That's a fairly significant shift.

There's no reason a high-strung, big valve 1584 couldn't do that, but that's not what you said you wanted to do.

You are right, I don't need as much HP as I thought I did. I started the thread before my thoughts were clear. I hadn't run the numbers on the other cars in the group. As Marc so rightly pointed out taking weight out is more than half the battle.

The Miatas are running about 19 lb/HP some of the Hondas are around 17.5 lb/HP

A 1600 lb car then only needs 84 - 91 HP on the ground to keep up with the current cars on the track (in theory)

I think I've talked myself into a 1584 to keep the spirit of B Sedan
Should have Solexs, but Weber 40 IDF's are in the budget
I can try the standard size exhaust since that is easy to change

That leaves choices for heads and cam that need to be made so I can order an engine.

Marc mentioned a FK-8 with 1.4 ratio rockers

The choices for cylinder heads is as confusing as the choices for cams.

Revised target is 84-91 HP on the ground out of 1584cc. Is this a reasonable goal?

What heads?
What cam?
Who to build it?

Randy

[FJCamper]

Hi Randy,

We ran B-Sedan with our 1973 IMSA Super Beetle back in 1975-76. In SCCA, we were very equal to the competition, but in IMSA (The BFG Radial Challenge) we had to contend with Devendorf's B210 and he had factory help. Dan's Datsun was much faster than we were.

We ran 48 IDA's (40mm venturis) on an 1835, Scat C65 cam, and the best custom heads we could get. That was enough for B-Sedan but not IMSA.

I don't know what you really want out of this project, but if you build a 1915 and sandbag a little, you can have a lot of fun. If you do start running up front, you will be protested.

You made an earlier comment about my liking the Engle 110 cam. I do, but the 110 is not an all-out road racing cam. It makes a killer autocross and short track sprint cam if you have realy good heads. Here's some video of us in 1600 trim with the 110 and 40mm (30mm venturi) Kads at about 11:1.

Taking down the BMW's
www.youtube.com/watch?v=yowKsYDy4UU

FI level RPM's at Roebling Road
http://www.youtube.com/watch?v=u1d3Swrn-YI

FJC

[RHough]

Hi Randy,

We ran B-Sedan with our 1973 IMSA Super Beetle back in 1975-76. In SCCA, we were very equal to the competition, but in IMSA (The BFG Radial Challenge) we had to contend with Devendorf's B210 and he had factory help. Dan's Datsun was much faster than we were.

We ran 48 IDA's (40mm venturis) on an 1835, Scat C65 cam, and the best custom heads we could get. That was enough for B-Sedan but not IMSA.

I don't know what you really want out of this project, but if you build a 1915 and sandbag a little, you can have a lot of fun. If you do start running up front, you will be protested.

FJC

My target is to have a car that can run with a Spec Miata and that I can drive on the street. There is no logic to that at all other than a good friend has a SM car and I'd like to run in the same group on track days. Keeping it in the spirit of vintage B-Sedan opens some other opportunities to play. Keeping it road legal allows me to do rallies too. I just want to have a car that is great fun to drive. I'm not ready to have a race only car.

What do you think a reasonable target weight would be for the car? A 1835cc would scale at 1835# in B-Sedan trim (and how did you get away with a 1835 anyway?) You wouldn't have any paperwork that would support a 1835cc Ghia would you? That would be great support for doing the same thing to my car.

Thanks for the inspiration in the Road Race Ghia thread ... or damn you for getting me started on this ...

Randy

[Marc]

If there'll be no objections to the aforementioned 40 P11s, a 9:1 1600 type I with decent stockvalve heads will make the 90/90 HP/torque mark at the flywheel and still maintain streetability on 91-92 (R+M)/2 fuel. But while you're asking about what carbs will be accepted, you may as well shoot for the moon and see if IDF Webers would be allowed since they're much easier to come by. They come in 40, 44, and 48mm versions so the strategy here would be to get it in writing that the 48IDF is illegal - that'd give you the option of running the 40 or 44.
The limited reading I've done on the subject of vintage racing rules indicates that they aren't particularly concerned about getting into intense tech'ing of the transmissions - so long as Reverse works, you're OK. This is the one area where VWs have an advantage over most marques, once you figure out what ratios are ideal for a specific venue, odds are that there are off-the-shelf gearsets which'll put you right there. The bummer is that it takes a lot longer to swap out a transaxle than an R&P set on a conventional drivetrain, but you did mention that you like to putz around in the garage
When we used to tour up & down the west coast, running on circletracks from ¼ to 4/10mi, we figured out that two transmissions would cover all - we had a split of 12% between 3rd and 4th with a 6% overlap from one box to the other, so even in the worst-case-scenario where we had to use the "wrong" trans for some reason, most of the time the gearing would still be close enough to stay competitive. For your needs I can see having one box with a short R&P and close-ratio 3rd (super-tight, like 1.58, 1.65, 1.75) to run as a 3-speed on short courses and another with 3.875 R&P (to make 2nd as tall as possible without the heavy expense of an aftermarket mainshaft); 3rd & 4th ratios would be chosen based upon the needs of the longer road courses on your schedule, and hopefully the 4th in that box would be tolerable for street use too.
To reduce drag as much as possible, the 4th gear teeth of the "3-speed" could be milled off, but it's a small gain. More pragmatic IMO to put in a .82 Bus 4th to make the trans marginally functional on a long course (or the street). It'd be like driving a 5-speed with 4th missing but the day could come where you'd be glad to have it.
For the gymkhana trans there could be a major benefit in welding up the differential if that's not disallowed. It's easy to detect, though, so not a smart place to cheat.

[Marc]

..You wouldn't have any paperwork that would support a 1835cc Ghia would you? That would be great support for doing the same thing to my car...

No such animal, never happened. Factory-stock never exceeded 1584cc. You might be able to defend 1603 or 1622, since factory-exchange replacement engines existed with a .5 or 1.0mm overbore, but it's nearly impossible to find serviceable pistons (or even rings) in those sizes. As I said earlier, if displacement is only checked using a P&G pump and not a full teardown you could cheat and declare it as 86.5x69 but build it with an offset-ground crank (85.5x70.65) that'd have comparable displacement. It'd be more practical to have one custom crank built than to be forever searching for strange pistons and rings, but technically you'd still be cheating so you may as well go 87x69 and cross your fingers when they bring out the pump.

Another option would be to have a destroked crank built, again a one-time expense versus always needing to hunt down oddball rings and pistons...87x68.2 is also 1622cc.

But if I was going to go down this road I'd build it 90.5x63 with 5.5" rods...it'd still pump <1622cc and I'll guarantee it'd make more HP.

[RHough]

..You wouldn't have any paperwork that would support a 1835cc Ghia would you? That would be great support for doing the same thing to my car...

No such animal, never happened. Factory-stock never exceeded 1584cc. You might be able to defend 1603 or 1622, since factory-exchange replacement engines existed with a .5 or 1.0mm overbore, but it's nearly impossible to find serviceable pistons (or even rings) in those sizes. As I said earlier, if displacement is only checked using a P&G pump and not a full teardown you could cheat and declare it as 86.5x69 but build it with an offset-ground crank (85.5x70.65) that'd have comparable displacement. It'd be more practical to have one custom crank built than to be forever searching for strange pistons and rings, but technically you'd still be cheating so you may as well go 87x69 and cross your fingers when they bring out the pump.

Another option would be to have a destroked crank built, again a one-time expense versus always needing to hunt down oddball rings and pistons...87x68.2 is also 1622cc.

But if I was going to go down this road I'd build it 90.5x63 with 5.5" rods...it'd still pump <1622cc and I'll guarantee it'd make more HP.

What do you know about the new Engle grinds in the FK4x Series? The FK43 looks really good.

Do you see anything wrong with this build from Aircooled Net:
69mm forged CW crank
88.5 bore
L3 heads
FK-43 Cam
1.4 Rockers
9.0:1 CR
Weber 40 IDF's
1 3/8" header with muffler

I think those will all play nicely together and get me on the road. Based on what I like or don't like about this engine I can change the specs for the next one.

R

[FJCamper]

Hi Randy,

Our IMSA 1835 was illegal. We VW guys depend on tech's inexperience to slip stuff by.

I do my best, mechanically, to bring a gun to a knife fight.

Might as well get caught with 94mm cylinders as 87's. I'm a big advocate of the 1915 if you want assembly simplicity, great heads, and all the compression you can stand or afford (race gas-- $$).

For a daily driver/part time racer, I'd recommend 44mm throttle body "Kadrons" (Solexes, actually) with up to 36mm venturis.

FJC

[RHough]

Hi Randy,

Our IMSA 1835 was illegal. We VW guys depend on tech's inexperience to slip stuff by.

I do my best, mechanically, to bring a gun to a knife fight.

Might as well get caught with 94mm cylinders as 87's. I'm a big advocate of the 1915 if you want assembly simplicity, great heads, and all the compression you can stand or afford (race gas-- $$).

For a daily driver/part time racer, I'd recommend 44mm throttle body "Kadrons" (Solexes, actually) with up to 36mm venturis.

FJC

My head hurts ...

Maybe I should post an add: Wanted $5000 worth of fast and reliable engine for Karmann Ghia



You are obviously a big fan of the Kadrons ... Why chose Kadrons over a pair of Weber 40mm IDFs? Can you list pros and cons of each or point me to a good thread on the subject?

R

[Stenis]

There is a group 3 (GT) FIA homologation (form 581) which is 1600cc. If you build it according to FIA period G (up to 1970 I think) you can have like 5% fender flares If I remembered right. As always when it comes to historic racing you have to prove that everything you mount on your car actually was used in the period of time (60s or 70s or what ever period class you are racing). At least here in Europe... I have a Ghia also that I am going to turn into a 1600cc class monster. The Ghia has a lot of potential being a RR car!

[Stenis]

Sorry. Period G8. Or year-71-75. Swing LSD, 1.6 engine, 2x48IDA, extraoilcoolers, KONIs etc. These are all parts which are allowed to use according to the homologation form 581.

[RHough]

Sorry. Period G8. Or year-71-75. Swing LSD, 1.6 engine, 2x48IDA, extraoilcoolers, KONIs etc. These are all parts which are allowed to use according to the homologation form 581.

Great information!

Do you know where I could get a copy?

R

[Stenis]

Accusfia should have them or else you can buy them through me from FIA europe (france)

[Stenis]

Hi Randy,

Our IMSA 1835 was illegal. We VW guys depend on tech's inexperience to slip stuff by.

I do my best, mechanically, to bring a gun to a knife fight.

Might as well get caught with 94mm cylinders as 87's. I'm a big advocate of the 1915 if you want assembly simplicity, great heads, and all the compression you can stand or afford (race gas-- $$).

For a daily driver/part time racer, I'd recommend 44mm throttle body "Kadrons" (Solexes, actually) with up to 36mm venturis.

FJC

If you get cought with illegal parts here in Europe you get a red dot in your HTP, If you do now fix them till next race or showup, you get banned.