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New Race Car to Us, Need Some Advice :)

 
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ChrisCXC  



Joined: 18 Oct 2019
Posts: 2
Location: Los Angeles, CA

PostPosted: Fri Oct 18, 2019 8:41 am    Post subject: New Race Car to Us, Need Some Advice :) Reply with quote

Hi Guys,

We run an E30 and a Lotus Elite on the west coast in Lemons, Lucky Dog and Champcar. You can learn more about our team here: https://www.facebook.com/bteamracing/

We've been doing it for over 10 years now.

A couple of us decided to add another car to the group with some new drivers.

We found a killer deal on a 79 SCCA ITB spec 924. It has a NASA and SCCA log book as well as a 2011 tech sticker for Rennsport. It hasn't run in about 9 years though. It seems to have once been a well loved car that was simply abandoned in favor of other racing projects.

Here is what we know about the car so far:
    1979 Porsche 924
    Caged (seems to be pretty well done)
    Still has the stock CIS fuel injection
    Ceramic coated headers and race exhaust
    Oil Cooler
    Stock Radiator
    Looks like the head and cam were replaced and not fully re-assembled
    Strut bar
    944 Suspension
    Early 944 Transaxle
    Maybe 944 brakes? (disks front/rear)
    Phone Dial Wheels (5 bolt)
    Lexan rear window (and stock glass too)
    Fiberglass hood (and stock metal one too)


The goal is to build a BULLETPROOF car. If there is anything we have learned from all those years of endurance racing is: Make it reliable and very simple. I'd personally love to make it go quicker whenever possible, but never sacrificing simplicity and reliability. Our motto is "keep it out of the pits".


We have all new safety gear, cool suit system, Fire suppression system, radios, Racecapture Telemetry, etc. just ready to drop in.

We simply know nothing about Porsche 924's.

So with that in mind, what should we do?
    Ditch the CIS and go dual carbs? Not for power, but simplicity in parts. Tuning carbs on a dyno doesn't scare me as long as it's simple from that point on.
    I'm assuming we will need a really good aluminum radiator..... (any recommendations?)
    We plan on adding a 22 gallon fuel cell, so no issues with fuel economy as we are limited to 2 hour stints in most series.
    Should we add an accusump?
    What are we missing?
    If we are finishing the top end build, anything we should do/check?


Any help from the brains here would be much appreciated!


Images: (happy to take more if needed, just ask)
https://ibb.co/12XwmFX
https://ibb.co/pXvm4j6
https://ibb.co/nBRwwY2
https://ibb.co/zGjJcwT
https://ibb.co/NTwgSJW
https://ibb.co/YWHPFN0
https://ibb.co/zNxzbcd
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MikeJinCO  



Joined: 08 Jun 2010
Posts: 804
Location: Maysville, Colorado

PostPosted: Fri Oct 18, 2019 12:51 pm    Post subject: Reply with quote

Only been racing this year. If the stock radiator has plastic tanks get rid of it. Brass tanks are good if the radiator checks out. Davis Rad. can make you a stock one. Wizard Rad. has one for a 944 Turbo, both in the $600 range. I got an ebay 944 turbo China clone all aluminum for about $200+ and so far so good. Mounting it takes some fab work and the hoses are different sizes so that takes a bit of figuring also. I took 2, 924 bottom hoses spliced together to make one bottom for the 944t and the top hose is a real cluge job. I don't run a fan at this point and with thermostat it stays at 180.

i have untuned 45 Webers and it looks like I should go down to 34mm venturis for the NA head as the flow stalls at about .400 lift. On the NA head polish the exhaust ports up to 300 grit. On the intake side smooth out the machined edge along the bowl behind the valve guide, gently smooth and flatten(a little) the sharp corner on the bottom of the ports, flow goes up about 10%. Match the intake ports to what ever manifold you are using, do not use the gasket as the holes are too big and not necessarily in the right place. I don't drive hard enough yet and seem to be getting about 6 minutes per gallon. I use rev limit of 6k with stock rod bolts. An MSD 6 ignition does wonders.

Look at what the NASA Spec944 guys do for suspension stuff, basic, but works. Making Delrin bushings work on the front of the lower control arm is pretty ugly and on the TB carrier the Delrin can be gruesome. I use aluminum front TB carrier mounts and a hard Powerflex Black TB carrier bushing. It took about 3 hours to fit and is just a fraction of the Delrin ones. Look up Pub Racing website for Vaughn's build also as a long step up from Spec944. I have GAZ Gold Pro coil overs at 400 lb in front and 275 back to go with a 23.5(stock) torsion bar. I have 944t sways front and rear(24 hollow, 18 rear on a stock suspension that works perfectly and 968 30mm front, and 22mm adjustable Weltmeister rear on the race car.
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Mike
Poco a Poco, '80 future track car
'77 924
cricketdesigns.com
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CÚdric  



Joined: 27 Aug 2004
Posts: 1893
Location: Sweden

PostPosted: Fri Oct 18, 2019 8:15 pm    Post subject: Reply with quote

The standard radiator works fine for endurance racing in my experience, just have good airflow through the oil cooler, to be on the safe side. And a radiator in reasonable good condition.

Brake caliper rebuild is definitely on the must do list, but you might have planned that already. With the correct pads the braking system is more than enough, but some ducting is always nice to get even better pad life, but you already know that if youve done endurance racing.

Oil system should be good, just keep the level close to the max.

I would do some simple ports polishing as mike says, theres some easy gains there if you already have the top end apart. Change all seals and gaskets of course. And all old water hoses while you have everything of.

Check through all the bushings and ball joints, its an old race car, things might be worn out.

If everything works i would keep the CIS, but it looks like everything is stripped on the pics, so carbs might be the easiest route.
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924RACR  



Joined: 29 Jul 2001
Posts: 8192
Location: Royal Oak, MI, USA

PostPosted: Sat Oct 19, 2019 12:34 am    Post subject: Reply with quote

If the car is running as-is, I'd leave the CIS. It is more reliable IMO than carbs, once it's running properly. But they don't like to sit, so it may not be any longer.

Stock rad can work fine - that's all we've ever used. That said, you'd save a decent bit of weight running an aluminum one. Maybe have the existing one tested by your local rad shop first.

Accusump would be very much adviseable, yes. Worth putting in a remote filter mount, while you're at it, for ease of maintenance etc.

And, in that area, a good heat shield on the starter plus a remote starter solenoid, so you can restart after spins.

If the head hasn't been installed yet, make sure to check the block for flatness with a straightedge. I went through a whole stack of head gaskets over the last two years because I was too lazy to check it, on a previously-raced high mileage motor, only to realize it was no longer in spec.

I've never found the 5-lug brakes to need ducting, not at ITB levels of power...
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
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ChrisCXC  



Joined: 18 Oct 2019
Posts: 2
Location: Los Angeles, CA

PostPosted: Sat Oct 19, 2019 4:19 am    Post subject: Reply with quote

That's great info guys! Keep it coming!

We are planning a work day this weekend to go over all of this and inventory exactly what we have. We should have some detailed pictures afterwards.
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CÚdric  



Joined: 27 Aug 2004
Posts: 1893
Location: Sweden

PostPosted: Sat Oct 19, 2019 4:41 am    Post subject: Reply with quote

The ducting is just to get more running hours out of the pads. Even the drum set-up is good enough for endurance racing, so the 5lug setup is more than enough. We probably have tighter tracks over here than you have, so more braking.

Don't forget to change the water pump, they are cheap, and its old and crusty.

Its incredible how well they work for endurance racing. The team i raced with dragged it out of an old barn, stripped, caged etc. Than put it through a season of 6,12 and 24 hours racing. Bone stock more or less, worked great, as long as it had race pads. Std pads lasted about 45 minutes
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Fifty50Plus  



Joined: 28 Feb 2008
Posts: 1048
Location: Washington DC area

PostPosted: Sat Oct 19, 2019 6:27 am    Post subject: Reply with quote

I swear by the Accu-Sump. I used to race BMW 2002s and the rod bearings would go when the pump cavitated during hard cornering. I put in an Accu-Sump and never had another problem. I put one in my first 924 race car about 5 years ago and didn't have any problems. The new owner forgot to open the valve and spun a rod bearing this year. I have another Accu-Sump in my new 924 race car and no problems in 3 years.
How do you know when an Accu-Sump is working? Feel the body after a run and if it feels warm, that means oil has been flowing in and out of it during your run but the engine keeps constant oil pressure.
I also run the 5 lug setup with vented rotors front and rear but no ducts. I use Performance Friction pads and they last about 10 weekends. No fade.
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car
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924RACR  



Joined: 29 Jul 2001
Posts: 8192
Location: Royal Oak, MI, USA

PostPosted: Sun Oct 20, 2019 1:32 am    Post subject: Reply with quote

Fifty50Plus wrote:
I use Performance Friction pads and they last about 10 weekends. No fade.


That's good to hear; we've seen comparable lifetime out of the KFPs, but they seem to be not as easy to come by.

How's the rotor life on those PFCs?
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
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Fifty50Plus  



Joined: 28 Feb 2008
Posts: 1048
Location: Washington DC area

PostPosted: Sun Oct 20, 2019 2:06 am    Post subject: Reply with quote

Rotors are fine. My prior 924 still has the original rotors that I installed when the car was built. We've been using the Performance Friction pads in all our endurance cars for the past 15 years. Prior to that we had problems with Cool Carbon continuously changing the compound on us.
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car
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