Porsche Enthusiasts Club Forum

I spent a bit of time with Nick from Nickson Motorsport the other day chatting about this. As the tittle I'm supercharging my 944 (8v lux 1984). Initially I'm not planning to go mad with boost, but would like a bit of room to run more boost if required. Probably 7psi initially with room to go up to 10.

The question is compression: I can do all or some of the following. Turbo pistions, turbo head, turbo cam. I'm thinking pistions may be enough, or head and cam maybe enough?

I've read some people run superchargers without lowering compression, but I think these are US spec which if I'm right ran slightly lower compression than European cars.

Any input would be great.

It was never the best show but I recall that wonderful show called 'Chop Shop' supercharging a 2.7. They actually had some good results from it bar the head gasket dying. I seem to recall that being a standard engine.

Hmmm interesting. I wonder if that was a standard gasket or a cometic one? Right off to YouTube to see if I can find the show....

Found it! Right, be back in 43 mins

I did a load of research on this. Basically you can run around 5PSI on a standard engine & 7-8PSI with an intercooler. After this you'll need to be clever with management to stop detonation. At a minimum I'd do a decoke & new headgasket. As excess carbon will increase detonation.
Note the existing management doesn't have much margin for modification as standard, so you may need new management.

I'm currently rebuilding an engine to go in, so it will be in good shape.... I hope. I've already rebuilt the bottom end, so would prefer not to pull the pistions out and swap them for something else, but how's the time if it's the best route to go.

I'm trying to find out what the compression difference would be with just a top end swap with a turbo head and cam tower.

I'm planning on running an intercooler and larger injectors. As for management I'm thinking of using the Augtronic ECU from Augment automotive.

As said low boost could be had without too much of an issue. But I have always found boost addictive. And low boost wont always give you what you desire, or you may soon get used to the performance and want to increase the boost. Which is where running low boost has its limits.

At 5psi you would prob only be seeing something like 200-210bhp ish. Which is ok. But if your having to spend 1500 pounds or so on management and mapping. It seems a lot of work and money for average gains. Boost is also what gives torque which in turn is what gives you the biggest performance gains. The more boost the more torque.

Really I would say 1 bar boost is what you should aim to run when spending all that time and money on going forced induction.

If you have the engine apart now. Then I would say a set of low comp pistons from a turbo is a very good idea. You may even be able to get some1 to machine the heads of your pistons slightly to reduce compression? Depends how much meat there is there.

I have a turbo head and cam etc, bolt that on and you have a proper turbo spec motor that you can put boost in and reap the rewards.

Im sure I saw a scrap bottom end on ebay you could steal pistons from

350 quid for scrap engine on ebay. Might be worth a punt? For pistons/rods and whatever ancilleries might come with it.

I have the majority of parts here to bolt to a non turbo engine to make a turbo setup. Exhaust/injectors/rad/downpipe/inlet/sump etc etc

I would say just go for a turbo. Get an engine rebuild that. Or get rods and pistons. Got some rarst rods and pistons in a box.

5 /10 psi won't give you another power for the out lay