My unorthodox 3.0L 16valve build using native 2.5 engine
05-02-2013, 01:19 PM
#16
Race Car
Thread Starter
I can't say for certain that the smaller bearings "solved" the issue. However, after my experience with free revving these engines, I will say that there is no way I would have abused the factory style parts as much as I had last year. My bearings looked perfect after 15k miles and some crazy rev limiter burnouts. I personally don't think the stock parts could have handled even 3 of the burnouts I did.
05-02-2013, 04:17 PM
#17
Rennlist Member
Sounds like a good way to go Sid. Rather than throwing all the parts on at once, work your way through this and add/subtract as you go. This is going to be fun!!
05-02-2013, 06:08 PM
#19
Race Car
Thread Starter
Turbo should always be selected for power goals IMO. In this case, since the compression is low, I would want something that is efficient at higher boost levels and may not spoil as fast as most 951 cars.
If I were not trying for 600+ hp, I'd go higher compression and probably a gt35 with a .82 hot side.
My Holset will probably be just a tad small. However, there have been a couple DSM cars run 154+ with them, so the potential is there in regards to airflow.
If I were not trying for 600+ hp, I'd go higher compression and probably a gt35 with a .82 hot side.
My Holset will probably be just a tad small. However, there have been a couple DSM cars run 154+ with them, so the potential is there in regards to airflow.
05-03-2013, 10:58 AM
#23
Race Car
Thread Starter
It would depend on the overlap. I won't do anything with them unless I can either A: use dual gears to control love separation or B: have some sort of variable cam timing. I won't know anything until I get to them.
05-03-2013, 02:38 PM
#24
Three Wheelin'
Chrenan, you gotta get a hold of dave... he'll tell you some cool stuff about this engine.
Sid, is this engine gonna run sans HG? Im looking forward to some pretty unheard of results with this little beast. No pressure
Sid, is this engine gonna run sans HG? Im looking forward to some pretty unheard of results with this little beast. No pressure
05-03-2013, 05:52 PM
#25
Race Car
Thread Starter
Oh no, this build will be using a cometic for now. It was my choice to just go with a flat deck. Dave is going to do something more elaborate. Myself, I chose to start with a "flat deck" only so I could quantify the results of the deck plate exclusively. Down the road, I plan on o-ringing the block and receiver grooving the head along with a copper HG. That is, if it is warranted. I don't know what kind of power it'll make, but I hope over 600 easily.
11-28-2014, 08:37 PM
#29
Rennlist Member
-944S head and stock cams. First go round the head will be completely stock. I will be pulling the head after a short while to do some port work, add stiffer valve springs and coat the exhaust ports
The 944S valve springs were recently superseded to the S2/968 valve spring. The original 944S springs (the ones that came on the S head, or replacement springs with a different part number from S2/968) had more spring pressure and more distance to CB than the S2/968. This made them the best Porsche spring for 4V performance applications. As long as they test ok, there's no need to change them for something with more tension. Further, the S and S2 intake cams are identical, but the S exhaust cam has more duration. Using it was an old S2 Firehawk trick to pick up around 10hp. I would think the S cams would be great in a turbo application. One further comment about the Porsche valve springs: Typically, aftermarket spring won't be as consistent nor as reliable. This has been my experience.
The 944S valve springs were recently superseded to the S2/968 valve spring. The original 944S springs (the ones that came on the S head, or replacement springs with a different part number from S2/968) had more spring pressure and more distance to CB than the S2/968. This made them the best Porsche spring for 4V performance applications. As long as they test ok, there's no need to change them for something with more tension. Further, the S and S2 intake cams are identical, but the S exhaust cam has more duration. Using it was an old S2 Firehawk trick to pick up around 10hp. I would think the S cams would be great in a turbo application. One further comment about the Porsche valve springs: Typically, aftermarket spring won't be as consistent nor as reliable. This has been my experience.
Last edited by michaelmount123; 11-28-2014 at 09:44 PM. Reason: Change "Any" to "Typically" in next to last sentence.
11-28-2014, 08:50 PM
#30
Rennlist Member
That's interesting Michael. Both about the cams and the springs. So you're saying that even the highest quality aftermarket springs are substandard to the stock Porsche S2 ones?