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Itching For A New Project, Road Legal "Semi" Rally
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TJC  



Joined: 04 Apr 2010
Posts: 601
Location: NW Arizona

PostPosted: Wed Nov 28, 2018 4:41 pm    Post subject: Itching For A New Project, Road Legal "Semi" Rally Reply with quote

For quite some time I've had a desire to build something based on a 924 NA but not quite sure what. Having a background in everything from drag racing as a kid, to road racing as well as pavement and dirt track ovals with Sprints and Midgets I realized that I haven't experienced Rally to any great extent. I was involved with SCCA Rally a few years ago as a sponsor when I imported Revolution Wheels but never got fully immersed in the sport. However I've always enjoyed watching Rally and with some fine desert roads all around me I think it's time to embrace the idea of building not really a full fledged rally car but more an occasional off road 924 that I can drive daily if I wanted to. I know some compromises must be made but I can deal with that!

Now having said that I hope to rely a bit on my fellow members who know a whole hell of a lot more than I regarding the sport in hopes that I am satisfied with the end result. Again I want to stress that I'm not building anything for competition but more of a toy. I don't expect it to be a show winner and am sure it will get it's share of bumps, bruises and cactus scratches after she's finished. I have a basic idea of what I want to do to the engine and as a personal preference I intend to replace the injection with a pair of Webers as I love playing with them and love even more their beautiful music! I would of course complement them with a proper exhaust, head work, bottom end rebuild with a rise in compression ratio and performance cam. This all leads me to my first question. In gravel rally usage what do most drivers prefer...low end torque or upper end power? My first instinct would be to go for the torque...yes, no? I'm not too concerned about top speed as I doubt if I'd ever get the car much above 90 mph in any circumstance.
I would probably strip most all of the interior, install a couple of purposeful seats and perhaps a simple roll bar but at least a harness bar so I could use proper belts. I'm not sure how crazy I'd go with the electrics such as relocating the fuse panel or going with circuit breakers but I do anticipate installing some toggle switches for various items. I would more than likely go with some extra lighting as well. I am curious as to what extent people go to with chassis modifications. Obviously proper shocks would be required and recommendations would be appreciated but other than freshening up the stock components what do most people do? Skid plates obviously would be utilized but what about raising ride height? Which sway bars are common? Any reinforcements needed to the lower control arms, rear trailing arms, steering rack mounts, motor mounts, etc.? If I end up with an earlier model with disc front/drum rear brakes will they be up to the task? Will the four lug hubs suffice? Again please keep in mind I'm not building a competition car but I still want it to be reliable and safe! Is some type of LSD mandatory even though I realize it's preferable? The gravel roads I'll be on will vary from hard packed and rocky to potentially sandy and silty. Will gravel rally tires be mandatory or a nice luxury? What tire could be a suitable alternative?

Okay, that's probably enough for now!!! I sincerely hope some of you will chime in and offer your expertise. I'm currently looking for the right "suspect" now and hope to start on something after the holidays. In the mean time I'll be doing additional research and probably have more questions. Thanks!
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1603
Location: Somerset, UK

PostPosted: Wed Nov 28, 2018 5:48 pm    Post subject: Reply with quote

All depends on the events you plan to partake in. If it’s anything like the uk then we have from mild to wild events with car prep dependant on the event. Some historic regularity rallies do not require stripping and caging. So look at the events first, may be speak to competitors and see which cars are already competitive
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1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
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TJC  



Joined: 04 Apr 2010
Posts: 601
Location: NW Arizona

PostPosted: Thu Nov 29, 2018 1:58 am    Post subject: Reply with quote

Carrera RSR, I don't plan on entering any events at all at this point. My main interest in building this type of vehicle is to take advantage of the trails and back roads that are in the area and state I reside, Arizona. "Offroading" as it's called, is extremely popular here and the vehicle of choice is usually a Jeep or something similar. I could use my BMW X5 but to be honest I'm not really fond of that vehicle, or similar type, as I find it to be too big and cumbersome and not at all fun to drive. It's better off in the hands of a suburban soccer mom and is currently up for sale to fund this project. Plus it's fun to be different. Many years ago I worked for a Peugeot dealership and often thought it would be fun to build a 504 rally replica...here in the States that would REALLY be different!!!

So you see I'm starting with a blank slate and not restricted by any rules or regulations...just imagination and of course finances!!! I'm basically just looking for a little direction and then I'll take off! BTW, I was following the UK 924 club on Facebook and your recent display was fantastic. All of the cars looked great! I'm interested in your new lighting setup...maybe you can give me some detail about it. Thanks!
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'95 BMW 318i/5 "Pearl"
'86 Porsche 944 Turbo...Parting, Not Much Left!
'87 Porsche 944 NA "Liebchen"

Still on the Prowl!

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morghen  



Joined: 21 Jan 2005
Posts: 7910
Location: Romania

PostPosted: Thu Nov 29, 2018 4:45 am    Post subject: Reply with quote

I have no racing experience but i can tell you what i'd like in a 924 NA..and a bit of what i'm going to do to my NA.
My target is very similar to yours, i want a cheap 924 so has to be a NA that can give me amazing driving experience and at some point, why not...take it to some historic rally events.
The historic rally events here always have the "modified" group. Competition is not really regulated there so its just get in and have fun.

So about the NA i'd want and hopefully the NA i will have.

First of all, all around polyurethane bushings and 968 sway bars.
Stiffer springs but nothing crazy stiff.
Slightly lowered suspension and proper 4 wheel alignment.
I'll go for the M477 option, the 5 lug setup because i already have the wheels that i want and 4lug brake pads and shoes are harder to find these days and same price as the 5lug stuff so...better braking for same money.
I wont strip ANY of the interior...the 924 interior is so light...its just pressed wood fibers...cardboard if you will...you wont save anything relevant by removing door cars, carpets and such things...you'll just make the car more tiring to drive.
The steering is a big issue for me...i need a some knee cleareance as i'm tall...so deep dish aftermarket wheel.
There is also the issue of how quick the rack is...its slow..very slow..because its unassisted and thats another problem.
The 924 is a quick and nimble car at low and mid speeds but the steering is too heavy for precision driving...especially if you use some grippy tires.
So i'll do an electric steering conversion and a quick rack (less turns from lock to lock).
I'll do a nice exhaust to my liking and forget about that aspect.
Enginewise...i like the CIS...so i'll likely keep it but the ideal solution would be EFI and ITBs.
On the engine power band topic, id take a low and mid rpm range boosting cam as i just dont like to drive with rev counter showing big numbers and to be honest the 924 engine does not sound particularly good at high rpms.
If i'll go any deeper...i'll get lighter pistons, rods, flywheel, ligher valves and followers.

Thats about it.
Revvier engine, ITBs would make it sound nicer.
Stiff chassis setup
improved steering
improved driving ergonomics
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gegge  



Joined: 27 Jul 2007
Posts: 1029
Location: Sweden

PostPosted: Thu Nov 29, 2018 5:46 am    Post subject: Reply with quote

I beg to differ, but 924 doesn´t sound particular good at high rpms

https://www.youtube.com/watch?v=ZEepQkhJKV4&t=102s

At 1:18 and 2:00 over 6000rps in third on narrow B-roads

Tick the box on 968 torsions, CIS, full interior and deep dish
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924 turbo -81 Carrera GT clone LSD Coilovers
924 -85 DP kit, BBS RS, M030 and tuned engine
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TJC  



Joined: 04 Apr 2010
Posts: 601
Location: NW Arizona

PostPosted: Thu Nov 29, 2018 5:51 am    Post subject: Reply with quote

Yes Morghen you touched upon a few of the reasons why I want to use a 924 NA. Since I have my '87 944 which is basically unmodified aside from an adjustable front sway bar and Koni's all around My need for a comfortable ride is satisfied. My goal with the 924 is to have more of a fun, toss around with wild abandon type of car that I won't get all anxious about if it gets a ding or a scratch here and there...like having Beauty and The Beast!
You make an interesting point about the 2L engine and it's upper rpm characteristics and that goes along with my "torque" over maximum output thoughts. As far as the brakes I see your point with you having bits already but if the stock setup will be sufficient with proper pads and shoes, and I hope someone will chime in to confirm that, I would be happy to keep that setup rather than changing everything over. First of all I won't be using the car daily and for all intents and purposes they will probably last my lifetime!!! Also with the money I save I can invest that in other things such as an extra set of wheels and tires so I may have a road set and an offroad set. Since my main objective is to use the car on gravel more than pavement I'm still thinking about raising the ride height. I know I will be driving on gravel roads quite a bit and will also encounter dry washes and creek beds when exploring old mining trails and such. I'm guessing you would be setting your car up for more of a tarmac rally scenario with the stiffer chassis setup and 968 bars. I'll need to research what would work better for my use.

Thank you for your input and if you think of anything else I should consider please let me know!
_________________
'95 BMW 318i/5 "Pearl"
'86 Porsche 944 Turbo...Parting, Not Much Left!
'87 Porsche 944 NA "Liebchen"

Still on the Prowl!

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Cédric  



Joined: 27 Aug 2004
Posts: 1766
Location: Sweden

PostPosted: Thu Nov 29, 2018 6:04 am    Post subject: Reply with quote

I've run endurance racing on stock brakes, they will definitely handle some gravel fun. I can really recommend hawk hp+ pads, great all-round and great fade resistance. Needs a couple of brakings to get in the sweet spot though.

Instead of raising the suspension, couldn't stock setup and taller tyre/wheel setup help enough with clearence?
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TJC  



Joined: 04 Apr 2010
Posts: 601
Location: NW Arizona

PostPosted: Thu Nov 29, 2018 6:29 am    Post subject: Reply with quote

That's good news about the brakes, thank you. Yes, if I have two sets of wheels I could use a taller tire to gain perhaps an inch or so with a gravel set and still have the car low enough for pavement use with a standard diameter tire...brilliant idea there Cedric!!!
_________________
'95 BMW 318i/5 "Pearl"
'86 Porsche 944 Turbo...Parting, Not Much Left!
'87 Porsche 944 NA "Liebchen"

Still on the Prowl!

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morghen  



Joined: 21 Jan 2005
Posts: 7910
Location: Romania

PostPosted: Thu Nov 29, 2018 7:10 am    Post subject: Reply with quote

Forgot about that, thanks for refreshing my memory.
Let me rephrase: my 924 sounds like crap

gegge wrote:
I beg to differ, but 924 doesn´t sound particular good at high rpms

https://www.youtube.com/watch?v=ZEepQkhJKV4&t=102s

At 1:18 and 2:00 over 6000rps in third on narrow B-roads

Tick the box on 968 torsions, CIS, full interior and deep dish

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gegge  



Joined: 27 Jul 2007
Posts: 1029
Location: Sweden

PostPosted: Thu Nov 29, 2018 7:41 am    Post subject: Reply with quote

I suggest that you keep the 4-lug due to the shorter spindlearms. Hence a shorter ratio compared to 5-lug by more than 10%. As you can see is in the video, easy even at low speed. If you are driving much on gravel (I do!) keep suspension soft and don´t use swaybars for maximum traction and grip. You only need harder suspension if you intend to do jumps. Long travel is good if the roads are really bad. Reindex and get longer 944 springs in front. Remember the thick skidplate. The balance of the 924 is perfect for relaxed driving and long slides. Regarding the engine, stock is a performer in the 3000-5000 rpm range but dull. For sprints or tarmac, I recommend more bite in the upper powerband. You don´t have to sacrify low-end torque, there is not much to begin with and with a reasonble hot cam the loss is just above idle. Lighter is better in every respect, loose everything that isn´t absolutly necessary. That goes for the wheels as well. Keep the 14" and buy graveltires. Or if you find 15" ultralight Citroën C5 steelies in aluminium like Cédric do.
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Carl Fredrik Torkildsen

924 turbo -81 Carrera GT clone LSD Coilovers
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black with low ET "Phonies"
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TJC  



Joined: 04 Apr 2010
Posts: 601
Location: NW Arizona

PostPosted: Thu Nov 29, 2018 9:33 am    Post subject: Reply with quote

If I keep the suspension fairly stock then I should be good for the gravel roads then, right gegge? I would refresh the bushings and shocks which brings up another question...shocks, do I stay with something close to stock or go with a Bilstein or Koni heavy duty type? My mind says that a heavy duty would be a better choice. I'm not interested in getting anything adjustable as this car is not for competition and I just want to have some fun without getting too serious. I will keep the sway bars however since I will be using it on the road as well. If I get more serious about gravel I can always disconnect the link. Now the big question, (financially speaking!) is for my intended use how important would it be to add a LSD? I doubt that whatever I buy will be equipped with a factory LSD, but it would be nice! It sounds like we're on the same page with the engine, minor modifications but nothing too crazy. Thanks for your thoughts and advice!
_________________
'95 BMW 318i/5 "Pearl"
'86 Porsche 944 Turbo...Parting, Not Much Left!
'87 Porsche 944 NA "Liebchen"

Still on the Prowl!

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Cédric  



Joined: 27 Aug 2004
Posts: 1766
Location: Sweden

PostPosted: Thu Nov 29, 2018 6:27 pm    Post subject: Reply with quote

Isnt the setup of the Repco rally car close to what you are after, fairly standard but a bit with some strategic rallymods ?


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TJC  



Joined: 04 Apr 2010
Posts: 601
Location: NW Arizona

PostPosted: Fri Nov 30, 2018 2:17 am    Post subject: Reply with quote

Yes Cedric, very much so. This car and the one that Jurgen Barth described in his book that he and Roland Kausmaul drove in 1979 are what has inspired me to take on this project...that and watching rally videos on Facebook, hahahaha!

I also want to build something different from the accepted culture of the big almost monstrous 4WD vehicles that dominant the off road arena here in the States. It would remind me of 40 years ago when I ran a dead stock little Subaru 4WD wagon in Ice Trials on the frozen lakes of Wisconsin and beat everyone's ass, especially the fellows who spent a fortune on their vehicles! Having some fun with a 30+ year old little Porsche 924 would have the same effect...very satisfying!!! Plus since Rally is not nearly as popular here as it is in Europe, Australia and other parts of the world it would be fun to show it off at some car shows and "cars and coffee" events. I'm sure it would get a lot of attention!
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'95 BMW 318i/5 "Pearl"
'86 Porsche 944 Turbo...Parting, Not Much Left!
'87 Porsche 944 NA "Liebchen"

Still on the Prowl!

www.ttrstomtatalovichracingservices.com
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XLR8  



Joined: 30 Mar 2016
Posts: 116
Location: Byron Bay, Australia

PostPosted: Fri Nov 30, 2018 6:20 am    Post subject: Reply with quote

Cédric wrote:
Instead of raising the suspension, couldn't stock setup and taller tyre/wheel setup help enough with clearence?


That's likely the cheapest and best route. Perhaps adjust the trailing blades on the rear to get a little more height, and some new 944 springs on the front may assist to get you higher - all considering the current handling balance of the car (to determine whether you want to go softer or harder springs to correct over/under steer tendencies).

As for sways, the earliest cars don't have mounts for a front sway bar, and their rear bar is ineffective. Later cars have front sway mounts (and no rear usually), and rear sways can be easily retrofitted and are the first thing I'd do!

968 sways will be overkill for a dirt focussed car. One needs some body roll to identify where the tyes are compared to the limits of grip. So perhaps thicker bars from a 944 would work. I have Turbo sways on mine, and she's really really flat ....
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XLR8  



Joined: 30 Mar 2016
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PostPosted: Fri Nov 30, 2018 6:24 am    Post subject: Reply with quote

Cédric wrote:
Isnt the setup of the Repco rally car close to what you are after, fairly standard but a bit with some strategic rallymods ?



Apparently it had a 928 brake setup. I have always been wondering how that comes together ....
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