924Board.org

[skrilla]

if anyone could give me any info on what turbo chargers are the best value ad what i would have to do to turbo charge my car would be great. i have a stage 2 cam from integral cam and that seemed to make a big diff. i just want more speed i love the car!!!

[Lizard]

aftermarket kits for the 924 NA come up on e-bay rarely keep your eyes open, but I always recommend just getting a factory turbo over turbocharging the 924 NA
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3 928s,

[My924gtc]

I have a couple of BAE turbo kits for the NA that I am rebuilding. Complete bolt on kits including RayJay Turbo, Wastegate, oil lines, intake plumming, and exhaust manifold. I will post a for sale thread when the rebuild is complete so keep an eye out.

Don't just throw your car away and run out and buy a 931.
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MJ
'81 924 2.0L T
'82 924 2.3L SC/EFI <---online fall '06

Sponsor of the 944 Cup and Super Cup
Sponsor of the "2006 Battle in the Badlands"

[brentil]

How much do you usually sell these kits for, and how often do you have them available?

I'm working on redoing a 1978 924 as well, and eventually I want to possibly turbo it, but not till I get all the other work done.
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1978 924

[My924gtc]

I currently have 3 of them, one I am keeping, one I am selling, and the other is for re-designing my own kit that I will eventually have for sale. I just lucked into these three so I don't have any others coming in.

Final cost on the rebuilt kit will be determined by hours spent, and how much parts cost. For instance the rebuild kit for the turbo is $175, so don't expect a giveaway, but it will be reasonable.
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MJ
'81 924 2.0L T
'82 924 2.3L SC/EFI <---online fall '06

Sponsor of the 944 Cup and Super Cup
Sponsor of the "2006 Battle in the Badlands"

[Douglas]

What is the continued drive train rating on the n/a torq tube under 1" drive shaft v. 931 slightly over 1" shaft?I've seen that the new VW beetles are rated over 500hp drive train stock.Personally what I'd do is the usual n/a stuff,get the flow as good as can be,maybe pull 140 hp?Then a cheap electric supercharger maybe get 155hp total?Should be interesting w/o lag and easily out do the stock 931 upto 100 mph,w/o a big stress on the smaller drive shaft.

[CBass]

Turbocharging a 924 is still a fair bit of work, even if you have a kit like the BAE. You won't see much of a gain unless you use an intercooler as well, and there's no telling when your fuel system is no longer going to be able to support enough fuel flow. You'd be better off getting the 931 CIS and it's goodies if you want to be on the safe side, and that's worth a couple hundred as well. Then there's the NA clutch, I'm not sure how much power it can handle.

What did those BAE converted cars make anyways, as far as power goes? 150hp? 160hp?

If you really want a 924 turbo, and you want to stick with the car you have now, your best bet would be to buy a 924 turbo engine and transmission, rebuild the engine, install it as well as an intercooler and turn the boost up to 14psi. With this combo, you should see around 220hp, which will make your lightweight '78 fly.

The factory made considerably changes when they built the 924 turbo engine, the cylinder head is completely different, and vastly supperior not only in flow, but in combustion chamber design. You'll be able to run much more boost on a 924 Turbo engine, more safely. The 924 turbo fuel injection system was designed and calibrated to work with a turbocharger, so you don't have to worry about leaning out and blowing up your engine. The 931 head gasket is much sturdier than the NA head gasket, because it's made to take higher pressure. The clutch and drivetrain are beefier, to handle the increased torque. The list goes on.
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'81 931 in various states of assembly

[kojab]

[ESC944]

I say fuel delivery isnt that big of a deal... problematic maybe... but do able... if you dont want to convert to a better setup, or any such thing... then you could just use a AIC (additional injector control) run say two injectors and tune accordinly, add maybe a MSD 6 BTM for boost timing control...

fabricate a turbo header or get one from a turbo car and install, plumb oil line to and from oil system ensure adequate oil pressure... done!

That of course is the simple no details idea... but their is slighly more to it.

However I would actually advise you to try something a little different.

Still run a turbo.... but how about this... Dump the stock injection and all that mess.

Convert to carburation, and it doesnt have to be side draft, you could acutally do this:

Install a cross over pipe, that brings the exhaust from the header over to the drivers side install the turbo hear, like in the 944 turbo. Setup either a draw thru or blow thru with the carb. Blow thru allows an intercooler, the draw thru doesnt, since fuel can and would pull in the intercooler.

Now to keep it simple, fabricate a simple mount for the carb that feeds the intake pipe, use a large two barrel or small 4 barrel carb. Basically either fabricate a complete intake or and adapter that lets you mount the carb, down side with a non-side draft is hood clearance... since you will not be running larger boost numbers I would acutally do a draw thru... since fuel will be delivered thru the turbo under pressure to intake... you could sit the turbo and the carb well under the hood line. and even mount a Carrera GT style scoop to feed air to an air filter that sits inside the scoop. Anyway with a draw thru... only issue might be hard cold starts... but just because a turbo isnt making boost off idle, doesnt mean their isnt sufficent air flow and fuel getting to the engine trust me thats not an issue.

SO you only have to worry about cold starts... easy... use a 5th injector.. install a injector in the intake pipe near the Throttlebody. rig it up to a hot switch... push the botton it sprays a little fuel into the intake and then engine fires... easy! From then on... its all good.

No fuel injection issues and you have a trick fun setup.

FUNKY! can you dig it?

Ok so on a serious note... why no one considers draw thrus cracks me up... you dont have to modify a carb... you just have to mount it to a plate and pipe that feeds the turbo. turbo feeds intake... and if you are running lean, you adjust the jets on the carb or go to a larger carb.. heck you can get a boat load of carbs out of the junk yard....

What you hate carbs? Well then go to a TBI setup, yea throttle body injection.

Either stand alone, not cheap but easy and not to expensive... or their are quite a few companies that can reprogram GM units, so you get a TBI setup from some 2.2, 2.4, 2.8 what ever engine and the control module... install with a modified chip... call it a day. If it worked on my VW Bug it will darn sure work on a 2.0 924. TBI is basically a carb for all intents.. but you can atleast program fuel curves and the like.. and its electronic... also easy to make work with draw thru or blow thru....

OH yea and loads of information on the web about using TBI for anything!!! Then you can go to BATCH FIRE injection, again loads of GM engines that had batch firing injection... simple matter of adapting setup to the porsche... not complicated and can be found in junk yards cheap.

Oh course I am talking junk yard approaches... maybe you need all the fancy parts...

I like carbs... easy to rebuild and loads of fun... great sounding too... plus very very low buck appraoch... now imagine telling someone when they ask... so you running carbs? You say yep... they say what kind? You say Carter 4 barrel or some such... hahaha

As for fabrication stuff... hemm... if you wanted to go blow thru... you need a pressurized carb... this is where TBI would be better... then build a intake manifold that looks like the 944 but the carb sits on it sort of like the old inline 4 and six fords....

I say if you want to improve your fuel injection, but dont want a compicated system go TBI from some GM donor car. Clean it up, get a custom chip... and wire it up.

PLEASE note my examples are simplistic... My comments are long enough with out extensive details... but my goal is that you can do anything to get boost and fuel to the engine, the real problem is what can the engine handle.

Then you have to worry about the clutch.. etc.. but getting boost to the engine can be very simple... its all a matter of goals and the work to reach those goals, if you just want more power... well thats not to hard...

I just love the idea of a 4 barrel 924 how about porsche does the "442" sure it aint an olds, but if you give it a 4 barrel and it has a 4 speed...hahahaha the PORSCHE 924 "4-4-2 limited" HAHAHAHAAHA oh yea I will get flamed for that... bahahaha but before you shoot me down... remember if you Torque me off enough, I will build the thing just so I can irritate you! hahaha and especially if it will run circles around your car... take that you porsche purist... oops... did I go to far?

Reality check... anyone want to bring me back to reality? Funny thing about the twilight zone... I have strange neighbors

[Khal]

Okay ESC944, reality:

Unless have reasonable skills with engine building (and I'm not talking changing the plugs and oil) and have some pretty good resources at your disposal -not least of all a decent workspace, the proper tools for fabrication and assembly, the necessary parts and/or money, money money (of course!) -then it's simply cheaper to sell the 924 NA and buy a Turbo. No ifs, buts or maybes.

If you're genuinely committed (and no doubt many here are, so I'm not baggin' anyone) then sure, give it a go!

But I honestly feel that if you think you're gonna turbocharge an 924 NA cheaper than you can buy a 924 Turbo, you're kidding yourself (besides, you miss out on all the Turbo's other good bits )
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'80 924 Turbo

[CBass]

While it's nice to address the issues of fuel delivery that simply, anything that involves adapting carburetors to the engine is going to require tuning by someone who has experience with them, especially when dealing with a forced induction application. Carbs are somewhat finicky and not the best choice for a street car.

IMO, there are two ways to go about turbocharging a '78 924 properly. The first is what I mentioned before, go the factory route. There have been many technological innovations since the early 80s, but Porsche knew what they were doing when they turbocharged the 924. Either get the 931 fuel system and retrofit it to the 924, along with a turbo manifold such as the BAE or a custom fabricated job, as the 924 Turbo manifold will not fit on a NA 924, or get the entire 931 engine and swap it in. In my opinion, swapping the complete drivetrain is your best bet, because everything is original, and there is no real fabrication or custom work to be done. The car can be easily repaired and diagnosed according to a haynes or factory manual.

The other method is similar, but involves the use of EFI to deliver fuel. Retrofitting fuel injection from another car is complicated, and involves a great deal of mucking around to get it right. Using most of the popular aftermarket systems is expensive, and requires the engine to be tuned by someone with experience tuning EFI systems. Megasquirt is by far the most cost effective, and the easiest EFI to purchase and program, and there is a vast network of Megasquirt users who can help you with any technical or tuning problems you might run into. Using EFI means you'll get a little bit better fuel economy, you can run a little bit more boost, and you'll still pass emissions testing most likely.

The best combo for ease of use, IMO would be a 931 engine running Megasquirt EFI, you could have a running engine in the car, rebuilt and making 250hp on 93 octane for under $2000.
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'81 931 in various states of assembly

[ESC944]

I do agree with CBass!

I believe that carbs cab be a pain, but they can be a lot of fun...

As for parts, cost etc of conversions, its really realitive to what you have laying around and what you want to build.

As for carbs vs. fuel injection, in the long run carbs often win out over fuel injection for a lot of reasons. One you only have to tune them, not program anything.. and carbs cab be very forgiving even under boost conditions, long as you dont go lean.

Case in point Tractor pulls... they use carbs and huge boost levels... for insane amounts of horsepower...

Fabrication... what fabrication....

You have to figure out a way to get the carbs to respond to the go pedal... yea that sure is hard?!!?

Now mounting up a single carb to a turbo... ok get a carb spacer that fits the carb, build a sheet metal box that slope down to the carb, basically look at the early Buick 3.8 turbo V6... it was carb'd. this carb box fits the turbo... now feed the fuel to the turbo, and run the pipe from the turbo to the stock intake. Plug the injector holes or weld them or install Water injectors... thats a thought.

Hemm a carb sapacer some spare metal... Some PVC pipe a few hoses and clamps and I am feeding fuel under boost into the intake system.

Tune the jets on the carb. 4 barrel is my choice...

Ok not its not perfect but it worked on my VW bug... and about a dozen cars since then.

Mind you this sort of approach is for the kind of person who enjoys tinkering and tuning.

IT IS NOT PLUG and play.

AS for adapting a TBI setup it isnt that complicated... but it isnt that cheap the support like for megasquirt is their, but not as great.

I say carbs are the easiest and cheapest. Especially if it is just one carb.

Blow thru is complicated because in the case of a porsche... you need the carbs to be setup and sealed against boost. Plus you have to adapt the carb to the intake system, then put a cap or carb hat on it that seals and maintains the boost.

I say draw thru, keep it simple and even simpler, find a side draft carb, single two barrel, mount it up to the turbo... same as the four barrel... again I can build most of this with PVC pipe then go get some spare exhaust pipe left overs and finish the system once I mock it up with PVC pipe.

Add a water holding tank. and have water injection for when I crank up the boost.

If you are affraid of running lean at high boost.. you can add a single or dual injector, down stream of the turbo, use a single manifold pressure switch that triggers the injecto or injectors...

Look it isnt rocket science and it isnt perfect and optimal. Lots of ways to set up a "barbaric" fuel delivery system and skip all the bs....

Tune the car and timing according, for a blow of valve, how about a radiator cap and neck, they are set to open the overflow at 7 psi, atleast the ones I used are...

Waste gate... use a turbo with an internal unit.

Turbo exhaust header my back side... use a cross over pipe and mount the turbo and carn on the drivers side and loose all the fuel injection junk!

The down side is like CBass said is tuning... carbs and a basic no frills setup does have it limitations... in terms of fuel economy and all that.

But if you want power... think muscle car... bigger carb... and in our case more boost....

Of Course that brings us back to my previous post and points, what can the engine handle....

Heck I would even take the 931 engine. Modifiy it slightly and loose the fuel injection system.... go with carbs to see what I could do... more boost, larger jets and carb, etc...

Anyway remember my solutions are "junkyard" solutions, stuff you can do with parts from other cars, without a lot of complications... they are not perfect or pretty.

See While I love fuel injection and can tell loads of ways to work with that... and improve on it... each stage has its limits, their is something cool about just adding a larger carb or bigger jets....

Instead of hemm, larger injectors, remap the fuel curve, some adjustments, even with system that will self learn and then just need tweaking...

So its all about what works for you... I use mostly fuel injection, and being a computer freak, love playing with code and the like... but

To be different and work with what I have.. I would rather improve on what I have sometimes than swap it out....

So if you stock injection system sucks... compensate... add additional injectors, run a little rich... and with modern electronics you can add a few injectiors and a controler cheap... along with a fuel air meter let the stock system do its thing and just adjust your AIC (additional injector control) to add fuel accordinly. Then use a MSD 6 BTM to addjust timing based on boost...

Of course again you are better off with a 931 engine... why? cause it can handle boost and the parts are designed for prolonged boost conditions, ie the engine doenst come apart... a NA motor can only handle so much and you arent going to run 12 PSI in a stock NA motor, especially not one that is over 20 years old, a 931 sure... crank it up!

So what do you want a little more power or loads of more power..... a 931 can give you both or even just swaping int he 931 engine and fuel sytem...

Now if you just want more power... modify yoru 924 a little do it your way and when you find that isnt enough power, modify it to the max, if that still isnt enough, buy somethign else and do that.

I look at owning a 924, 931, 944, 951 or even a 928 as a hobby and just aother kind of hot rodding.... but then I am a little warped...

Really with any project you need expectations, what is the end result you want, and you need realistic goals.

Then decide what compromises or limits are good for you, is it all about function or do you want form or form and function, etc...

Then what other limits, money, parts, time, skill, etc...

Then go do it.

[ESC944]

One other thing about finicky carbs...

Lots of old carb'd cars still running.... cold weather with carbs sucks, but you can get around that with an extra injector or some such.

My 76 Chrysler cordoba had a Big Block w/ performance manifold, cam, headers, etc.. and ran great forever... I added boost first a supercharger, then a turbo then two turbos... all using a carb. Draw thru.. feeding the turbo, then a carb spacer welded to a hat that bolted to the intake in place of the carb. Differnt size carbs all the way up until, with the twin turbo it was a blow thru configuration, Two turbos feeding an intercooler, one single pipe off intercooler to the carb hat.

Only when I went to a blow thru setup, did I have issues with driving it on the street... I had to install a by pass valve for off boost air flow, like starting the car and idle, this was a pvc plumbing piece from home depot... after that I drove it everywhere and broke a lot of drive line parts... to much torque, but thats another story....

My point is weather might be a factor, poor care of your parts another... but if my car with 100,000 miles on it still ran good before I mucked around with it and so do a lot of older cars... all you need is a good tune up... gas mileage is a different issue! Now after I mucked around it ran good, ate a lot of gas and shredded a lot of tires.. it go so bad I had traction bars, leave springs moved in and huge 305/50/15 tires and still was spinning them on hard launches on the street.

Nothing is perfect when you are working with an old car and fitting it with aftermarket, custom or one off stuff... but I say... again work with what you got...

BTW last version of that cordoba had twin turbos, and a custom fuel injection, using the performance intake and a GM based TBI setup. That was a little expensive... of course the max boost I ever ran was 12 PSI on race gas, with water injection and it was to much, broke that sucker... hahaha but what a ride!!

Carbs are not for everyone... but they are very forgiving... fuel injection requires a lot more know how to setup, modify or install... beyond the fabrication... wires, ecu, injectiors, fuel lines....

I still love fuel injection... for better fuel economy... but a boosted carbed engine is just beautiful.... but thats just me....