Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

At a XRoads with my build, what to do?
Goto page 1, 2  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions
View previous topic :: View next topic  
Author Message
winddude  



Joined: 15 Jan 2020
Posts: 61
Location: Vancouver Island

PostPosted: Mon Nov 16, 2020 1:35 pm    Post subject: At a XRoads with my build, what to do? Reply with quote

I'm at a crossroads with the direction to take for my 924 build. It's a '80 N/A, running and driving, the interior is gutted. My goal is to turn it into a bit of a track car., primarily for autocross and lapping days, eventually I might try a few hill climbs.

Here's where I'm stuck, a few options:

1 - A tame build, trying to get as much as I can out of the 2L 924 engine, start with a bike carb conversion ditch the mechanical fuel injection. Swap in higher rate strut bars in the back and ground control coilovers up front.

2 - a parts 944 is for sale, with complete running drivetrain. Should I swap in the complete 944 drivetrain? I'd gain a stronger trans, 5 stud wheels, and another 30-40hp. But sacrifice some durability.

3 - A rather clean looking 944 is also for sale at a decent price. Buy the 944 and sell the 924. I don't have room for that many vehicles right now. Unfortunately.

I should also mention there's an ideal donor for sale that would be an ideal candidate for a locost build I've been dreaming about building for a long time.

I would appreciate feedback and your input. Cheers.
Back to top
View user's profile Send private message
MikeJinCO  



Joined: 08 Jun 2010
Posts: 961
Location: Maysville, Colorado

PostPosted: Mon Nov 16, 2020 4:25 pm    Post subject: Reply with quote

Having built a race only car, my opinion.

Most important Learn to Drive--Learn to Drive Repeat-repeat.Go to a driver school if you can find one. Only mod needed, some decent tires

If its running well, leave the motor alone, it's difficult and expensive to get not very much more power. Probably the cheapest, effective thing to do is buy the thinnest Cometic head gasket and pick up maybe .5 in compression ratio. Then time it to 41 degrees at 3500rpm, 924RACR says that is the best.

Put it the largest 944/968 sway bar combination you can do. I changed to the new 944 control arms at about $25 each then put sways off a 944 turbo (24mm hollow and 18mm rear)on my street car, amazing difference(some fabrication required). If you insist on stiffer springs find some 200 lb fronts and about a 160 lb torsion bar, Porsche or VW using Bilstein shocks-a lot of time required to do the t-bars. I think big sways easier to do.

Get/make some stainless steel brake lines and bleed brakes. Porterfield has some better R-4S pads for the 924. Anything to help the brakes.

And most important Learn to Drive--Learn to Drive Repeat-repeat.

Put in a decent driver seat and some real belts, you can pick up new outdated belts from any race shop, offer 50% of what their asking as they really have almost no market so negotiate a bit. When you start going around corners at speed it is hard to hold yourself in the seat without a good seat and belts.

Repeat learn to drive

I have maybe 24 hours of track time in 1.5 years and I'm still scratching the surface on learning.
_________________
Mike
Poco a Poco, #033 '78 Vintage racer, SCCA Dp-81
'77 924
cricketdesigns.com
Back to top
View user's profile Send private message Visit poster's website
morghen  



Joined: 21 Jan 2005
Posts: 8274
Location: Romania

PostPosted: Mon Nov 16, 2020 6:51 pm    Post subject: Reply with quote

Unless you really need a cheap race car i'd start with the 944.
If its performance you want, then the 944 is a no brainer, already having all the upgrades you can put on the 924.

Or wait for my supercharger kit to finish development, do your suspension and brakes upgrades on your 924 and get it supercharged
The supercharged 924 will be faster than a 944 on hillclimbs.
Its CIS only though, so keep the k-jet.
_________________
SUPERCHARGED Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2102
Location: Somerset, UK

PostPosted: Mon Nov 16, 2020 9:19 pm    Post subject: Reply with quote

More power = faster down the straights
More lightness = faster everywhere

Just strip it and drive it......change tires, sway bars etc. as and when you need to. Just drive it...... Have fun, learn to drive it faster

Forget bike carbs......more issues than solutions. Won't be much faster if any
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
924RACR  



Joined: 29 Jul 2001
Posts: 8373
Location: Royal Oak, MI, USA

PostPosted: Tue Nov 17, 2020 12:56 am    Post subject: Reply with quote

I'll definitely say it's not worth doing the parts swap (944->924) - massive amount of work for such minimal gains.

I think working with the car you have as a known good runner is a better idea - less debug than starting over. Build the chassis with the 944 brakes (if not already there), add spring more than bar, that has much more speed potential IMO, and get good dampers - Bilsteins preferred, probably need some custom race bits if you go far on spring rate. Make the motor light and happy, give it a big oil cooler and an accusump.
_________________
Vaughan Scott
Webmeister
'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
Back to top
View user's profile Send private message Send e-mail Visit poster's website
winddude  



Joined: 15 Jan 2020
Posts: 61
Location: Vancouver Island

PostPosted: Mon Nov 23, 2020 9:31 am    Post subject: Reply with quote

MikeJinCO wrote:
Having built a race only car, my opinion.

Most important Learn to Drive--Learn to Drive Repeat-repeat.Go to a driver school if you can find one. Only mod needed, some decent tires

If its running well, leave the motor alone, it's difficult and expensive to get not very much more power. Probably the cheapest, effective thing to do is buy the thinnest Cometic head gasket and pick up maybe .5 in compression ratio. Then time it to 41 degrees at 3500rpm, 924RACR says that is the best.

Put it the largest 944/968 sway bar combination you can do. I changed to the new 944 control arms at about $25 each then put sways off a 944 turbo (24mm hollow and 18mm rear)on my street car, amazing difference(some fabrication required). If you insist on stiffer springs find some 200 lb fronts and about a 160 lb torsion bar, Porsche or VW using Bilstein shocks-a lot of time required to do the t-bars. I think big sways easier to do.

Get/make some stainless steel brake lines and bleed brakes. Porterfield has some better R-4S pads for the 924. Anything to help the brakes.

And most important Learn to Drive--Learn to Drive Repeat-repeat.

Put in a decent driver seat and some real belts, you can pick up new outdated belts from any race shop, offer 50% of what their asking as they really have almost no market so negotiate a bit. When you start going around corners at speed it is hard to hold yourself in the seat without a good seat and belts.

Repeat learn to drive

I have maybe 24 hours of track time in 1.5 years and I'm still scratching the surface on learning.


I'm working on, unfortunately the driver training course this past summer was cancelled due to covid, hopefully next spring. I maybe have 35-30mins of track time in the past 6 months. I need to start doing some lapping days.

Good call on the seats.

Running well is a relative term. The warm up regulator is shot, not a big issue, I just need to stay on the accelerator until it warms up. My bigger concern is a bit of an inconsistent idle, which starting to worry I may have a worn cam. I've gone through the ignition system and the tune up with out eliminating it.


Last edited by winddude on Mon Nov 23, 2020 9:35 am; edited 1 time in total
Back to top
View user's profile Send private message
winddude  



Joined: 15 Jan 2020
Posts: 61
Location: Vancouver Island

PostPosted: Mon Nov 23, 2020 9:32 am    Post subject: Reply with quote

morghen wrote:
Unless you really need a cheap race car i'd start with the 944.
If its performance you want, then the 944 is a no brainer, already having all the upgrades you can put on the 924.


I do prefer a cheap race car, I like to "push limits"
Back to top
View user's profile Send private message
winddude  



Joined: 15 Jan 2020
Posts: 61
Location: Vancouver Island

PostPosted: Mon Nov 23, 2020 9:33 am    Post subject: Reply with quote

Carrera RSR wrote:
More power = faster down the straights
More lightness = faster everywhere

Just strip it and drive it......change tires, sway bars etc. as and when you need to. Just drive it...... Have fun, learn to drive it faster

Forget bike carbs......more issues than solutions. Won't be much faster if any


The interior is stripped, I 100% need better tires. I need to drop the back end at least since removing all the weight it's sitting high in the rear. I thought I'd go stiffer sway bars as I reindex.
Back to top
View user's profile Send private message
winddude  



Joined: 15 Jan 2020
Posts: 61
Location: Vancouver Island

PostPosted: Mon Nov 23, 2020 9:38 am    Post subject: Reply with quote

924RACR wrote:
I'll definitely say it's not worth doing the parts swap (944->924) - massive amount of work for such minimal gains.

I think working with the car you have as a known good runner is a better idea - less debug than starting over. Build the chassis with the 944 brakes (if not already there), add spring more than bar, that has much more speed potential IMO, and get good dampers - Bilsteins preferred, probably need some custom race bits if you go far on spring rate. Make the motor light and happy, give it a big oil cooler and an accusump.


I agree a big project, butt what I can pick up a 944 parts car with complete drive train and 2 motors is not much more than I'll have to pay for the parts to do a brake swap. I've been keeping my eye out, nothing local, and shipping to Canada is expensive, I was planning to grab some when I was down in the states this past summer, but that didn't happen.

PS: If anyone has the rear spindles out in BC, please let me know!
Back to top
View user's profile Send private message
safe  



Joined: 18 Mar 2017
Posts: 210
Location: Sweden

PostPosted: Tue Nov 24, 2020 12:05 am    Post subject: Reply with quote

Properly driven and with adjusted drums, good brake pads and some cool air directed to the brakes, you don't need more brakes than you have. Its not good good, but adequate.
Its about braking hard, consistent, for a short time. Basically threshold braking or no braking.

A 944 is heavier, more drag but more space for tires. But you really have the space for all the tire you need in a 924 with the right rims.
Better tires, better suspension => less need for brakes

I think the the 924 body shell looks better than the 944 when you get the right wheels and stance. Sleek! For me that is not unimportant.
_________________
/Magnus, Stockholm Sweden
=======================
Porsche 924 -79 NA, under EFI and turbo conversion
Back to top
View user's profile Send private message
CÚdric  



Joined: 27 Aug 2004
Posts: 2073
Location: Sweden

PostPosted: Tue Nov 24, 2020 12:46 am    Post subject: Reply with quote

Agree that the standard setup is a good starting point, ive been to hell and back with n/a brakes on race tracks on a standard 125hp 924 and never ever had them fading (as long as the car had decent pads suitable for race tracks), and the pads lasted a long time aswell. What i dont like with that setup is the sponginess in the brake pedal that you get with the drums, and that they need to constantly be adjusted to have proper clearance to the drum. So in the long term the 5 lugs are a good upgrade, but not needed to start race tracking
_________________
1980 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2102
Location: Somerset, UK

PostPosted: Tue Nov 24, 2020 1:14 am    Post subject: Reply with quote

Stock brakes, albeit with race material front pads, rear shoes, fresh race brake fluid, R tyres......... how much harder on stock brakes can you be?

https://youtu.be/Hv8DrQcKghU
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
winddude  



Joined: 15 Jan 2020
Posts: 61
Location: Vancouver Island

PostPosted: Wed Nov 25, 2020 5:38 am    Post subject: Reply with quote

Great video! are those all 924 NAs with 4 bolt and rear drums?

That's good to hear on the brakes, I'm was slightly worried about fade on lapping days, apparently the local track can be quite hard on brakes, https://islandmotorsportcircuit.com/

Heard stories from one s2000 owner who caught his pads on fire, but he pushes quite hard.
Back to top
View user's profile Send private message
jacobroufa  



Joined: 18 Nov 2016
Posts: 309
Location: Rockford, IL

PostPosted: Sat Nov 28, 2020 5:46 am    Post subject: Reply with quote

I took my 81 n/a for a track day this summer and literally had the best time I have ever had in a vehicle in my life.

Hard agree with all the folks here that you should first learn to drive. Instructors and experience can show you things you never thought to think about. It'll be a long time before I will consider myself anything more than a novice driver.. Push even a slug like these to the limit and you are working hard to keep it there!

Get a good set of tires and as much seat time as you can. I was surprised to find out how well I could keep up with and outpace the modern Porsches in the corners, so much so that depending on the size of the straight I could keep in front of them there too. The only place I found lacking is power for long straights.

Would not worry about brakes either. My first time out ended up spinning because I hit them too hard.. there's plenty of stopping power if they're bled and adjusted properly.

Enjoy winddude. There's no feeling like it.
_________________
1980 Porsche 931
1981 Porsche 924 Weissach
Back to top
View user's profile Send private message
Fasteddie313  



Joined: 29 Sep 2013
Posts: 2130
Location: MI

PostPosted: Sat Nov 28, 2020 7:01 am    Post subject: Reply with quote

I so wish their was an opportunity to track/autox drive reasonably close to me..

Have never done it ever.. Closest one is over 2 hours from me..
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions All times are GMT + 11 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group