Slow , slow slow 930

[maximo]

I have a problem since I bought the car,
the car does not come out fast before 4000 rpm,
in first gear is very slow. The mechanic check the compression,
ignition , timing,CO etc ..all ok

..electric problem ? KJetronic ???

Mine is a USA 87 930

Thanks ... Max

[mooney265]

my vote is timing is too far retarded... but, you said it checks out OK??

at one point, my timing was a little too far retarded and the car "slowly" got up to speed... not any more!!

[maximo]

is very strange , the timing is ok .
i am very complicated

[mark houghton]

Originally Posted by maximo

is very strange , the timing is ok .
i am very complicated

Let me venture to guess that what you are experiencing is the typical stock un-modified Porsche 930 low compression engine and old 3LDZ stock turbo. Completely stock, the 930 is a dog off the line and only really turns on...and violently...above 4000 rpms as the turbo finally builds boost. It's the nature of the beast. These cars were not meant to be fast off the line for drag races, but will kick some serious butt on a rolling start. How does it do in 2nd gear, say about 3000 rpms and you stomp the accelerator to the floor? In about 2 seconds it should launch you to full boost and 70 mph at least.

Want more or different performance? Lots of things can be done with simple bolt-on stuff....and a little $cash$.

[maximo]

Originally Posted by mark houghton

Let me venture to guess that what you are experiencing is the typical stock un-modified Porsche 930 low compression engine and old 3LDZ stock turbo. Completely stock, the 930 is a dog off the line and only really turns on...and violently...above 4000 rpms as the turbo finally builds boost. It's the nature of the beast. These cars were not meant to be fast off the line for drag races, but will kick some serious butt on a rolling start. How does it do in 2nd gear, say about 3000 rpms and you stomp the accelerator to the floor? In about 2 seconds it should launch you to full boost and 70 mph at least.

Want more or different performance? Lots of things can be done with simple bolt-on stuff....and a little $cash$.

in second at 3000 , slow , heavy , at 4.000 most happy but nothing special,
in first is exaggerated the slow , without torque

[mark houghton]

New spark plugs lately? Weak spark due to a failing CDI unit or coil? Air filter clean? Valves properly adjusted? Boost leak somewhere, or the turbo itself failing?

Tell us more about your car...totally stock, or modified and how?

[maximo]

Originally Posted by mark houghton

New spark plugs lately? Weak spark due to a failing CDI unit or coil? Air filter clean? Valves properly adjusted? Boost leak somewhere, or the turbo itself failing?

Tell us more about your car...totally stock, or modified and how?

totally stock , new coil , new sparks , no weak spark , new air filter,
valve adjuster and no leaks . Is very strange

[tj930]

Other tangent:

Are you getting full boost?

About 5 years ago, a succession of clumbsy mechanics taking the engine/gearbox out of the car managed to damage the magnesium, I/C mountings. Result - intercooler blowing off the top of the engine!

[911st]

Might check the turbo. When damaged they can get slow but will usually whistle. Exhaust restriction is a possibility. If you are still running the cat, it might be clogged.

If the inlet overrun valve is not working correctly is can slow boost response between shifts but should not effect first gear much.

The muffler is the best place to look for an increase in boost response over a stock car. The K27-7200 comes in faster and is more efficient on boost. Those two mods alone can get you to .8 bar by 3000 or soon after.

There is also solid gains to be made on the ignition side.

(Esoteric opportunities to increase response: If it is a double connection Pot on the dist, it can modified to increase total amount of boost and vac retard. Then set timing at idle instead of at RPM. This will get more advance off idle and at cruse but keep on boost timing stock for better throttle response and MPG. -- Also, some tuners have moded the inlet overrun valve to stay open at idle/cruse to spin up the turbo in reserve then close when accelerating for faster boost response. -- It is also possable to mod the WUR so the metering plate will move quicker with acceleration for less intake restriction. )

Not an expert, just my two cents.

[mark houghton]

Originally Posted by 911st

If you are still running the cat, it might be clogged.

So true on old clogged cats. Also, remote but possible is that your boost recirculation valve (piston) may be stuck open (it should only open when vacuum is present). That would prevent boost from building.

The question was already asked: Are you seeing full boost but still no power?

[maximo]

I really appreciate your help,
The mechanic called and told me it seems the problem is fuel delivery.

thanks , really thanks

Max

[mark houghton]

Originally Posted by maximo

I really appreciate your help,
The mechanic called and told me it seems the problem is fuel delivery.

thanks , really thanks

Max

Then your mechanic should check the WUR control and system pressures as a starting point. Also, the fuel metering plate/arm attached to the fuel distributor head may be sticking and not moving freely down as air intake increases. That would result in a very lean mixture and fuel starvation. If your mechanic is familiar with CIS, then he'll figure it out.

[Miguel Antonett]

What about a picture of the car, it might help...

[dewolf]

Fuel pump or fuel filter. Changed my fuel filter and the thing went miles better. The difference was night and day.

[maximo]

Originally Posted by mark houghton

Then your mechanic should check the WUR control and system pressures as a starting point. Also, the fuel metering plate/arm attached to the fuel distributor head may be sticking and not moving freely down as air intake increases. That would result in a very lean mixture and fuel starvation. If your mechanic is familiar with CIS, then he'll figure it out.

Thanks , now the mechanic check the WUR ,
he believes that is the problem,because the fuel pressure is too low

Max

[maximo]

sorry me again !

what is this??? , porsche call " fuel Cycle " ( black part with conector )