3.0 Liter turbo thread-Experienced builders please reply
01-10-2004, 06:13 AM
#16
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Originally posted by John Anderson
to date, our best Hp is 310 rear wheel, with a KK K26, but that little turbo just runs out of breath and boost level was pretthy high, too high to be able to last...we are using the stock DME on both cars. THe change out in computers mean a ton of harness work. We have just added the big garret to the S2, and are installing Big Reds, as soon as we get this stage out of the way, we will dyno tune it and tell about the results. I'm not looking for peak HP numbers, so you most likely will see a solid 340hp at the wheels. We will shoot for this while trying to keep boost under 1 bar.
Take Care
to date, our best Hp is 310 rear wheel, with a KK K26, but that little turbo just runs out of breath and boost level was pretthy high, too high to be able to last...we are using the stock DME on both cars. THe change out in computers mean a ton of harness work. We have just added the big garret to the S2, and are installing Big Reds, as soon as we get this stage out of the way, we will dyno tune it and tell about the results. I'm not looking for peak HP numbers, so you most likely will see a solid 340hp at the wheels. We will shoot for this while trying to keep boost under 1 bar.
Take Care
01-10-2004, 03:41 PM
#17
Interesting reading. Not sure the approach here. Shorter Rods to acheive a lower Comp. ratio. Boy is that backyard engineering at its best. That changes so much. Higher Piston speed, short Rod ratio and changes the VE of the engine.
If you want to Turbo these engines, then change the Piston to lower the Comp ratio. Keep the engine up to its original or better spec. Don't lower the spec just to Turbo it. Any shop offering such cheap engineering is selling out your dream. BTW, the cost of Pistons is typically lees then a set of Rods. But I will concide that Pauters are cheap. You get what you pay for I suppose. Big, heavy, and a Rod with very poor Beam strenght.
If you want to Turbo these engines, then change the Piston to lower the Comp ratio. Keep the engine up to its original or better spec. Don't lower the spec just to Turbo it. Any shop offering such cheap engineering is selling out your dream. BTW, the cost of Pistons is typically lees then a set of Rods. But I will concide that Pauters are cheap. You get what you pay for I suppose. Big, heavy, and a Rod with very poor Beam strenght.
01-10-2004, 10:10 PM
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Good point. Shorter rods = less displacement = loss of low end torque.
Shaving the pistons sounds like it is a pretty good way to go - currently, over on the 928 board, there is alot of discussion regarding this for supercharging 32 valve 928 motors. Being able to shave abit off the piston is permitting up to 1 bar boost on these motors with a net result of ~500HP at the rear wheels. Granted, the 928 is heavier than the 968 by about 500 lbs., but it is a very interesting increase in output.
I am currently in a stroker project on the 928, but also looking ahead for a turbo project on a 968.
Any and all info gleaned will be happily digested and saved for future reference.
Shaving the pistons sounds like it is a pretty good way to go - currently, over on the 928 board, there is alot of discussion regarding this for supercharging 32 valve 928 motors. Being able to shave abit off the piston is permitting up to 1 bar boost on these motors with a net result of ~500HP at the rear wheels. Granted, the 928 is heavier than the 968 by about 500 lbs., but it is a very interesting increase in output.
I am currently in a stroker project on the 928, but also looking ahead for a turbo project on a 968.
Any and all info gleaned will be happily digested and saved for future reference.
01-11-2004, 12:16 AM
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Just to add another option, mmmbeer posted a thread on the main 944 board about his 968 turbo conversion.
He used a 2.5L 944 turbo crank with 968 rods & pistons with a 968 block and head. That de-strokes the engine to 2.7L and yields a compression ratio of 7:1.
I agree the best way to do it is with lower compression pistons but as of now (other than boring and sleeving the block for JE pistons) they don't exist for 944S2/968 with a 16V head.
He used a 2.5L 944 turbo crank with 968 rods & pistons with a 968 block and head. That de-strokes the engine to 2.7L and yields a compression ratio of 7:1.
I agree the best way to do it is with lower compression pistons but as of now (other than boring and sleeving the block for JE pistons) they don't exist for 944S2/968 with a 16V head.
01-11-2004, 01:33 AM
#20
If you want to turbo these engines, and make the modification worth while, performance and reliability, then the Liners and Pistons are the best option. I know it costs more, but with all the failures the 944 block have, the Liner route is by far the better way to go. BTW, be careful of your choice of Piston. The big bore Pistons you mentioned have a history of Pin Boss failures. This is a well known fact.