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Doug, did you deck your block?
Stock is 230mm = 9.055"
You've got a ton of deck clearance with the numbers plugged in there. Might want to find a set of pistons with slightly higher compression distance..
8.3:1 compression ratio and Non interference
The only other viable piston choice is a 4.030 bore piston, the same one Shawn and sid used for their 2.85 8v builds. The problem is, the 16v combustion chamber is about 35% smaller than the 8v, which raises compression a significant amount. The pistons usually used in 8v 2.85 builds would yield something like 10.2:1 compression, totally inappropriate for a boosted motor. Running them .18" down in the hole isnt ideal, but I think it will be ok. A nice side effect is that the motor is non interference, even dynamically. The pistons I chose, if used with an 8v head, would yield something like 7.3:1.
Edit: Yes the block will have to be decked after sleeving. 9.03 is just what I'm guessing I'll end up with. It may be slightly higher, but it should all work out. as long as my compression is over 8:1 it should work out pretty well. I know nothing about the pistons shawn used in his 3.1 build, (if I had to guess, I would say he is running the JE 138103 piston, -16cc dish with a 1.125 pin height, 4.030 bore) but if I had to take a guess I would suspect he is running similar deck clearance to what I will be seeing, I'm guessing he is running ~.15" in the hole? Maybe he'd like to chime in on this?
Really? I'm around 2425 now (dry), no carbon fiber. Fiberglass front end (hood is only a skin) and dash. Metal doors, quarters, roof, etc. There is almost no wiring on the car (fusebox is gone, only have a few fuses), and the only undercoating/seam sealer is under the cabin - none on the front of the car, none inside. Goal is to get where I could run at 2500 lbs as an S, should I decide to do that. Although that may dictate 17" wheels and small brakes.
Biggest impediment, IMHO, to losing weight on these cars is mindset. Everyone to whom I talk in person says "that's only a couple of pounds" for everything I mention. OUnces add up to pounds, but most people want stones at a time. If you get in there and take out weight anywhere you see it, you'll end up with a very light car. If you get in there and think "this isn't much, not worth the effort" you'll be miffed at why you can't get lighter.
FWIW, wiht 1/4 tank of fuel, my car is:
FL - 695# FR - 700#
RL - 739# RR - 742#
48.5% on the front, and only 8 pounds different left to right. Actually, that is from when the car was about 50 pounds heavier, and running about 230 pounds of ballast. There is NFW I would have gotten there if I weren't super Type-A about the weight in this car.
I ran a 924 D/P chassis (933) for many years with a 4V 944 engine. It weighed 1970 lbs wet (sans driver). Yes, you can get there.
MM
Just ordered some plenum material from ross machine racing, on the fence if I should order bell mouths now or not since I just got these!
They taper from 50mm at the inlet to a 46mm butterfly, and then down to 43mm where it would meet the head on the bike. I dont know if I could get away with just putting a radius on the 50mm inlet vs getting the 2" RMR velocity stacks. I'm not sure how I would even pull off velocity stacks since I was planning on using the stock 30# bike injectors as secondaries, which sort of forces me to put the throttles directly up against the head (or as close as I can manage to keep the overall height of the intake in check, it still needs to clear my strut bar). Suppose they wouldn't need to be that close since they would only come online when pressure, velocity, and airflow was already very high through the intake track? I could weld the front of the ITB's to the back of the stacks and then weld elbows to the rear of the throttle body castings, then weld those to the S2 runners? Problem is I'm shooting for a total runner length, including the head port and stacks of under 12". This should get interesting. I'd love to hear what you think Michael!
The Can Of Worms has officially been cracked wide ******* open.
I ran a 924 D/P chassis (933) for many years with a 4V 944 engine. It weighed 1970 lbs wet (sans driver). Yes, you can get there.
MM
Not as light as Mike's car, my 84 944 was 2130lbs wet also no driver. There was a significant amount of weight I could have removed from that car still. It still had an all steel tub and doors. Glass front end only.
Clearly the 924 or 944 n/a are much lighter platforms to start with! We can't get near those weights although we probably have more 'stuff' on board. I'm sure moving to a lexan windshield would drop a few lbs but we have to run glass up front. Lexan on sides and rear is ok.
Got all the 16v belt drive conversion stuff in, and I have located a block and crank; which I should be getting my hands on soon. And to provide the proper amount of kick in the ***...
I still need to get an S2 intake to hack, pistons, and to get the block sleeved. After that, its just finishing the intake, machine work on the block and crank, and then assembly! I'm also thinking about doing the clutch while I'm in there, I'm running a spec 6 puck with a high clamp load pressure plate, but I'm still doubtful of its ability to the hold 16v stroker torque.
Wish I had a k26 to compare it to, the HX35 is a decent sized turbo that flows more than its appearance suggests
just examining the internals. Everything looks great. I am going to paint the valve cover and put fresh tensioner pads and a new chain on it, after that its off to the hot tank! Then I'm going port it slightly and clean the casting up. Then ready to bolt on!
07-29-2014, 11:06 PM
