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cleethorpes  



Joined: 26 Jan 2004
Posts: 186
Location: cleethorpes (oddly enough!)

PostPosted: Mon Jan 26, 2004 8:07 am    Post subject: turbo Reply with quote

Would fitting a turbo to an n/a 924 engine be a painless procedure?
I wouls be looking at fitting a 270 cam, and maybe a more efficient induction system if anyone has any ideas??

cheers
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Lizard  



Joined: 03 Nov 2002
Posts: 9364
Location: Abbotsford BC. Canada

PostPosted: Mon Jan 26, 2004 12:28 pm    Post subject: Reply with quote

the consensous of the board is; if you want a turbo charged car buy a 931, there are BAE turbo kits out there and windward kits however it is always better to go factory, too bad they dont have a factory turbocharged 928 mmmmmmm,

as per the intake manifold, no point,

if you want to squeeze every little bit of power out of the 924 engine, convers to EFI, and then custom fab 40mm individual throttle bodies for each cylinder, convert to a 931 head with a good port and polish job, of course then you will have to have custom pistons fabbed up as the NA pistons will result in a compression of about 6.7:1 so you would need custom pistons probably about 11:1 cr would be opt, and then you will need a custom set of headers as the 931 exhaust ports are slighty larger than the NA, now after all this work and money to do this you still will have less power than a 931, and you will be able to do nothing else to get any more power out of it,

the 924 is not a power house, it is a classy sports car that most people own for the history/name, if you want something with desent power, or you can get over 200bhp then just get a 931, if you want something to handle be able to stop on a dime, have class, and more than enough power, but still able to draw more power out of the engine, then buy a post 86.5 928 and either bore and stroke it to 6.5L or add a SC w/ intercooler, when done properly either of those can produce more than 500 rear wheel horse power,

the 924 is a very fun car to drive, yes it is slow, but that might be better for those of us with led feet
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cleethorpes  



Joined: 26 Jan 2004
Posts: 186
Location: cleethorpes (oddly enough!)

PostPosted: Mon Jan 26, 2004 9:30 pm    Post subject: Reply with quote

Cheers for the info.

Was hoping for an easy way to squeeze a few more bhp out of her.

Would the cam alone be worth the effort? (well not that much effort!)bearing in mind a piper 270 cam with all the bits n bobs would cost under 200??.

By the sounds of it, I'm better off using the money to modify the 911 I have not yet bought
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Eturbo924  



Joined: 09 Nov 2002
Posts: 2187
Location: Londonderry NH

PostPosted: Tue Jan 27, 2004 12:41 am    Post subject: Reply with quote

The ways to power.
9.3:1 pistons. Worth about 10-15hp.
Then cam and port and polish head with header and free flow exhaust. That exact number can be had at my site under 924 power tricks/bolt on 2

It gained around another 10-15 hp with those numbers. Then they went on to use carbs and this car ... with out the piston modification.... outran a stock 931. So you can make the 924 more powerful than the stock 931. Of course you can boost a 931 and smoke this car also.

I think with 9.3:1 euro pistons, a ported and polished head with cam, a header with free flow exhaust and you will be good to go. Should get about 140-150 hp out of a car with less complexity and less weight than the turbo.

You can then start looking at things like electronic dis timing and auto adjustable cam spockets and such. But those are good for another $1K.

The modifications above will not be cheap either unless you find used parts and are willing to do the r&r yourself.

My car is much more powerful than stock. I have a ported and polished head, mild performance cam, larger throttle body, cold air intake, ported intake manifold and free flow exhaust with header. I ran a 931 on the highway this summer. I had no difficulty staying with him. Now by the looks of his car it was likley not at its peak but I had a little in reserve.

I would stay away from the 931 head. It is a lot of work. Yes I am still considering it but.... remember if you use this head your engine is now going to be an interference engine. Throw the timing belt and the valves and likely pistons are junk. Stay with the 924 head and go with 9.3:1 pistons are you are safe I beleive.

Eric
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1982 924
1987 928S4
Parts Parts Parts and More parts.
E-mail me for parts you need!
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cleethorpes  



Joined: 26 Jan 2004
Posts: 186
Location: cleethorpes (oddly enough!)

PostPosted: Tue Jan 27, 2004 4:42 am    Post subject: Reply with quote

Combined piston and cam would be good for a few hp then.

In your oppinion, would a performance air filter, on a stock exhaust make any difference?

Only had the 924 a short while, it pulls well but really doesn't seem to like revving. No smoke or other visible signs of a problem but it feels like its being held back.

Gonna check the timing, replace leads, dizzy, rotor, plugs etc maybe that will cure it? Any idea what could be causing it??
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OR_Sunset  



Joined: 04 Jan 2003
Posts: 312
Location: Veneta, OR

PostPosted: Tue Jan 27, 2004 6:26 am    Post subject: Reply with quote

There a couple good upgrade paths out there.

One would be the tech-friendly way... do all your mechanicals (exhaust, port/polish, cam, compression) then fit EFI, DIS, MAF and variable cam timing... then everything can be computer mapped. Applebit knows a bit about this stuff.

Another way would be to rely on old fashioned power you can tune with a screwdriver... up the compression (9.3:1 are available if you look, up to 11:1 is do-able, JE will make custom pistons), balance the reciprocating mass, port and polish the head, use a stage 2 cam, bolt on some Weber sidedrafts (and spend lots of time jetting them properly), use an aftermarket ignition system, headers/exhaust, fit an aluminum flywheel, etc.

I chose to do most of the non-techie stuff... I will readily agree that doing all of the above mods will result in a fairly peaky car that really likes to be wound up, and isn't crazy about slow in-traffic driving.

Neither of these methods will get you anywhere near a "fast" car by modern standards. I just bought a 2000 Plymouth Neon for $5000. It is less than what I have spent on the Porsche. The car is every bit as fast, and is bone stock. Of course, the gear ratios are less desirable, the engine isn't as free-revving, and it doesn't have the handling.

I could spend $5000 and make the Neon a "fast" car... that still didn't have the handling of my 20 year old, invaluably imperfect, relatively slow german sports car.
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82 924 N/A -
9.3:1 CR Pistons, Dual Webers, Stage 2 Cam.
4-1 Headers, DynoMax exhaust, Monza tips.
MSD 6AL Ignition, 944racing short shift kit.
Through hood cold air intake with scoop, K&N.
Silver/Blue.
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Eturbo924  



Joined: 09 Nov 2002
Posts: 2187
Location: Londonderry NH

PostPosted: Tue Jan 27, 2004 8:33 am    Post subject: Reply with quote

A good tune up is always the first thing you should do. That way you have the proper base line for your modifications. Read the articles on my site.

If you do not either change the pistons, cam or port the head... nothing else will make any difference. No cold air intakes, no larger throttle bodies, K&Ns headers... nothing.

The head cam and compression are the big issues. I would start with Port and polish with a cam. Then if you have the money while the engine is apart... do the pistons. I would not go to radical on the compression or the lift on the cam. One it will make a peaky motor as noted and two... the higher the pistons come up and the higher you lift the valves... the more change you turn an otherwise simple motor into a interference design. I think Jons is that way now and he mashed some valves recently. I could be wrong but I think he mensioned it.

Anyway. You can make the car quite quick with those modifications. Not 951 fast but quite able to hold its own with many of the hot hatch backs. Then take them to the auto-x and really show them what the 924 can do.

Oh you might also want to go the weight reduction route. Take out the unessesary items and lighten up where you can. That along with the power increase will make the car feel much quicker!

Mine will not outrun a C5 corvette but it will beat many cars across the intersection. Quick not blindingly fast is the way I would describe my car.
_________________
1982 924
1987 928S4
Parts Parts Parts and More parts.
E-mail me for parts you need!
Drive Fast!
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81turbo  



Joined: 03 Nov 2002
Posts: 1065
Location: Oakland, CA

PostPosted: Tue Jan 27, 2004 8:40 am    Post subject: Reply with quote

Actually I wouldn't touch your pistons. Since you quoted a price in Pounds I am assuming you are in England and already have the 9.3:1 pistons.
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OR_Sunset  



Joined: 04 Jan 2003
Posts: 312
Location: Veneta, OR

PostPosted: Tue Jan 27, 2004 9:31 am    Post subject: Reply with quote

Yeah... the head, headers and cam make quite a boost by themselves. port and polish, Headers and intake _will_ help (bigger throttle body, cold air intake) if not HP, in terms of throttle response.

Personally, the $500US spent on the Weber carb conversion was worth every penny just in throttle response. The engine is VERY quick to respond with 4 independent throttle plates.

The power band will move up some, and with the stage 2 cam I have been running, winding up third gear is really important, and where a lot of the fun starts.

I don't know about standing starts, but acceleration from 30 to 90 is pretty zippy (2nd through 4th)... then 5th gear just eases on everything over that with a slow, consistent pull. Actually, it's kind of rare around here to get enough open road for any real WOT driving. By the time you wind out a couple gears, you are usually looking at someone's back end.

Not for everyone, as the motor tends to have more "personality" for lack of a better word.
_________________
82 924 N/A -
9.3:1 CR Pistons, Dual Webers, Stage 2 Cam.
4-1 Headers, DynoMax exhaust, Monza tips.
MSD 6AL Ignition, 944racing short shift kit.
Through hood cold air intake with scoop, K&N.
Silver/Blue.
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cleethorpes  



Joined: 26 Jan 2004
Posts: 186
Location: cleethorpes (oddly enough!)

PostPosted: Tue Jan 27, 2004 10:03 am    Post subject: Reply with quote

It just occured to me that I already have the 9.3:1 pistons!.

Hopefully the timing is whats retarding the engine, and a quick tune will sort it out.

Other than that I'm pretty certain the release bearing is shot, so I'll be dropping a new clutch in, can't wait having heard how 'easy' that is...mmm... yeah!
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