924Board.org

[Bumblebee77]

Hey all, i've checked around on the site and there seems to be a bit to read about at least the economy and the performance question but i find it easier to talk to people about it.

Some of this will apply to the Aussie (Specifically South East Q) users but i'll gladly accept anyone's input.

First off is the economy of the 924. I've got a stock 77 NA model and was wondering if my economy is standard or if there's any little things that can be done to improve it. So far i'm only on my third tank since i bought it and i get around 400km out of the tank.

I think i'm ready to start tweaking my car bit by bit. As far as performance mods go, i know from what i've read that there isn't a lot that can be done to the NA 924 that will drastically improve this without bucketloads of cash being thrown at it. There's a few little things i'd like to do that would be obvious; save a little weight where i can, eventually get the Audi throttle body but apart from these things, what mods would you guys personally recommend? Keeping in mind that for the time being this car still needs to be my daily driver and i have a finite amount of $ to play around with. I know i've asked a similar kind of question before and after the other research i've done some of the suggestions seem to point to heads/valves...? exhaust/header...? Airflow...? Apart from some work i can try and do myself, i understand that T&D Automotive in Brissie are some of the best guys around when it comes to Porsches. Anyone have experience with them?

I do have a final query about my exhaust. When starting the engine (i assume its mainly cold starting) i naturally have to give it some throttle to keep it running for a moment or so before allowing it to idle. There's a spray pattern on my garage floor (and anything in the firing line...) from my exhaust of black/grey spatter. I'm assuming its unburned fuel residue?

[Mahatma Gadhni]

You shouldn't really give it any throttle when starting. It should start without throttle and then idle.

Fuel economy should be a bit better, even with "spirited" driving.
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1984 924 2.0 NA

[ideola]

The black spray pattern from the exhaust sounds like it could be running a bit rich, which might explain why you're not getting better fuel economy. Before you consider any performance modifications, you should do a full and complete diagnostic of the fuel delivery system to make sure the CIS is performing optimally. Once that is done, you should replace every single vacuum line on the car. If either of those elements are needing attention, you will only make matters worse, and you will end up chasing your tail diagnostically. Both of those preventive measures can have a direct impact on fuel economy.

Once those things are completed, you might consider running an aftermarket ignition that delivers better spark, combined with a high performance coil. Those items combined with standard copper plugs might help you burn the fuel more efficiently. It's doubtful you will see much performance increase, but they should help you achieve optimal fuel efficiency.

The Audi TB conversion will make your fuel economy worse, because you will be effectively driving at WOT more frequently. It won't add power, but IMO, it does dramatically improve throttle response, and the fun factor. It makes the car feel faster, even though it really does very little in terms of generating more horsepower.

I know it's easier to ask questions and discuss...but you really should make an effort to read the information already posted here. Many of your questions are answered directly in the 924 FAQ (Technical), which you should be obliged to at least read once (memorization would also be a good idea )

Regarding performance modifications, I strongly encourage you to put together a project plan, even if it's relatively modest. <- That thread has links to some of the best posts here on the board, so you owe it to yourself to do your due diligence. In your case, you might not be looking for "the killer build", so your project plan might go something like this:

1. Preventive maintenance of the CIS system
2. Preventive maintenance of vacuum lines
3. Full tune up (fuel filter, plugs, wires, cap, rotor, air filter)
4. Aftermarket ignition (MSD or Permatune) + aftermarket coil
5. Audi TB conversion
6. Aftermarket headers + new exhaust

This approach doesn't even get into the areas of suspension & braking, which can also be significantly improved to enhance the driving experience.
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erstwhile owner of just about every 924 variant ever made

[Bumblebee77]

Thanks ideola. I don't mean it to sound or look like i don't check the FAQ's or use the search function because i do. I just find that there's so much information to absorb. At the moment i'm finding it easier to kind of do both. Ask the questions and do the readings as well. May sound weird... but the information seems more 'real' when it comes from another user in response to a direct question. I think i'd compare it to reading a text book (which will pretty much have all the info i want/need but is presented in a slightly drier fashion and the sheer volume of information can be intimidating to a newbie) to asking a lecturer who generally has first hand knowledge and can put the words in a different way which can sometimes mean all the difference. Its the combination of the two forms of info together which is most applicable.

Something was telling me that i should probably be getting slightly better fuel economy. I'd read the cars were built and designed to run on lower quality fuels. My old Celica starting doing something fairly similar before it was eventually taken off the road and i could literally see its fuel economy decrease. I think over a space of about 12 months i lost about 30-40 km out of my tank range. But at the time i was also having gearbox and carburettor issues that pretty much no-one could solve.

Oh... and as far as a 'plan' goes... i think eventually i'd like to have the "little sleeper car that looks stock from the outside but dazzles through the twisties." A little extra horsepower would be nice but i'm still realistic about the car and its potential in this department without an almost endless budget and drastically reducing everyday driveability. So aside from modest improvements, i'm thinking most work will eventually go into suspension/brakes and other handling specific mods.

[924er]

get BOSCH parts especially wires!
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80' Porsche 924 NA - Slower then a S L O W
86' Porsche 951- New toy

[Khal]

On the fuel economy thing, my '81 Turbo was regularly getting about 10l/100km's (around 23.5mpg) just trundling around town. Much less in spirited driving, obviously I've read time and time again that an NA 924 should get at least that kind of fuel economy, and generally much better (anything up to 7.85l/100km's or about 30mpg). So if you're over the 10l/100km's mark, then you're certainly running less efficiently than you could.

I have the 62-litre (about 16.4 gallon) tank in my car, same as the NA's, as far as I know (some other Turbos have an 84-litre tank -nearly 22.5 gallons!). I ran it dry once. I know, I know, you're not supposed to... but it was in the interests of science! Anyway, I got about 530km's from the tank. You should be able to get that kind of economy, assuming you're not pedal-to-metal at all times.

I always used BP Ultimate (98 RON) petrol. Can't claim that it's more or less efficient to run Premium Unleaded Petrol but it probably doesn't hurt...

I've taken my car to T&D a couple of times. They are great guys and have always done a good job. But they are on the expensive side. Their bread and butter seems to be building racing Porsches, they always have a few floating around the carpark. crunchie 57 (another Brisbanite and member of the 'board but he doesn't post much) likes to joke that T&D's standard quote is fifteen hundred bucks Change the oil? Fifteen hundred bucks. Change the timing belt? Fifteen hundred bucks But seriously, I'd definitely recommend them, just be prepared to pay high-end Porsche pro prices.

Perfomance mod's? Where to start..?

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'80 924 Turbo

[Bumblebee77]

Wow. Sounds like i should be getting a lot better economy than is currently the case. I always run it on Premium though i don't currently have a specific brand/type. So far i've used Shell Vortex (i think that's the new name, it used to be Optimax.) Ideola gave me a few things to check on. Be the first time i've done anything really constructive with a car. So long as there's no fabrication or anything complicated like that though, i'd be keen to at least give it a crack before i get halfway through and freak out.

I'd love to check out T&D but the $ factor does scare me. And being something of a newbie, i'm always wary about being taken for a ride so to speak.

[Smoothie]

I'd put injector flow test high on the priority list - mainly to check the spray patterns...should be fine atomization and fan shaped pattern from each.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Smoothie]

A yahoo search on "cis injector ultrasonic cleaning" found this place, among others - http://www.jaguarfuelinjectorservice.com/Injector%20photos.htm . Photos there show the difference between bad and good spray patterns.
That also illustrates how with extreme differences in output between injectors, you can easily have some cylinders running lean, while others are too rich.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Bumblebee77]

So an injector test and clean is called for? I'm guessing from these pictures that some form of special machinery/expertise is required that i sadly do not have...

Also, i've found this website has an extensive list of new replacement parts. www.autopartswarehouse.com Its an American site and isn't especially cheap but seems to have a lot to choose from. Anyone have any experience with this site or the parts listed therein? One thing in particular has me a little unsure though. In looking into the ignition coils for a 924, there seems to be a massive spread in price. From a Bosch replacement unit for around US$56 right through to Fireball and Accel units which can range in price from US$50 up on to almost US$300.

[RC]

Driven conservatively at the speed limit could get from Hornsby to Coffs, 550Ks on a tank with CIS. However lucky to get 400 now with EFI around town as I have a heavy right boot. Yours should be similar.

Check your injector volumes (stubbies work well, empty them first of course ) and spray patterns. They may be OK. Suggest do a full tune first, oil & filter, air & fuel filters, plugs, cap, rotor, check leads, cam belt, and valve clearances. Stock timing is 10 initial but will improve at 15 deg and be OK with 98 or even 95.

Personally would suggest buying a set of tools, sockets, spanners, feeler gauge, allan keys, and timing light instead of paying any shop. Much better economically and a great learning experience with personal satisfaction doing it yourself and doing it right. Unless you own a bank or dont intend keeping the car long!

IIRC the site you mentioned doesn`t ship outside of the US. I have often bought from these US suppliers and found them very well priced and receive goods in a week.

https://www.autohausaz.com
http://www.rockauto.com/catalog/raframecatalog.php
http://www.pelicanparts.com/catalog/shopcart/944M_catalog.htm

IMO ignition upgrades are generally expensive snake oil particularly on a stock engine, unless you go programmable. Spend the money on tools and tune up parts, a sound investment.

Roger

[Bumblebee77]

Okay... so you're saying that trundling around town i should maybe be getting a little better than 400 out of the tank but likely not loads more?

My partner's dad is one of the smartest folks i know mechanically but i think he's a little afraid of the unknown quantity of the Porsche (specifically the injection system). Although admittedly i think that may be more due to the stereotype that most people seem to believe of "oh, its European/exotic so it must be crazy complicated" and from what i've been lead to believe, once you get down to it, these cars aren't that mechanically complex. Maybe i should enlist his help, between us we've got the tools (apart from maybe a few specialist pieces) and as i said earlier, so long as there's no fabrication involved, i'm fairly keen to give most things at least a try.

So maybe i buy the bits and pieces i need to start from scratch from those sites (ie, new filters, pumps, plugs etc) and have a go or get a pro to do at least the first major tune-up so that i have a decent platform to build on? Still worried about the prices i've heard thrown around for things like that though...

EDIT: Holy crap, just got off the phone to T&D Automotive in Brissie to satisfy my curiosity about their major tune-up/service rates... apparently about 1k! Jeezus... at that rate its cheaper to take it to the Porsche centre Brisbane!

[RC]

Depends dramatically how you drive. Sure granny wouldnt get 500 around town with lots of stop/ starts and not holding up traffic. Better cruising of course. Personally I like to use the power and dislike getting blown off by volvos and SUVs from the lights. Since its new fun to you you`re probably not getting the best economy either.

Possibly may have a sus WUR but again suggest doing at least the basics yourself and see how it goes. Then consider taking it to a specialist to have the pressures checked or perhaps by then your confidence will have increased and you may wish to buy the gauges for half the price and DIY.

Forgot to mention- get yourself a HAYNES manual. Great "instruction book", Au$50 here or US$14. Not sure if AZ have them but likely the best for all filters and tune up parts. Honestly 20% of Repco or supercraps price. Get all you need from one supplier if possible to minimise shipping, but still works out less than half the local cost.

These cars are fairly simple to work on really and with some assistance shouldnt be a problem. If you have access to tools and experience thats a bonus. Sure you will get all the additional help you need here.

Roger

[Scorpio]

[Bumblebee77]

The Haynes manual was literally the first piece of kit i purchased once i took ownership of the car. Found one on ebay and snapped one up. Also got a fairly water damaged (but otherwise in ok nick) one from the PO. Been reading a few bits and pieces so far but again, a lot to absorb.

Goldy in early June? Is that the club meeting nite? I just realised that alas i won't be able to get along to the meet at Willowbank short of a rostering miracle between now and then. But should be able to make the next "meet'n'greet" nite. Looking forward to actually speaking to a few people first hand.