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Glad to see you are back and healthy. It looks as if you are using the 996 gt cup heads? also looks as if you are using the matching cup cam box? 996? If so the 997 cam box uses coated lifters and has a larger locating pin. I am not sure about where your testing is at but I am having debonding issues with the main bearing at my power level. Also I have crushed a few H beam rods (carrillo's) under power not detonation. I am now looking source these two components else where. One other thing I noticed is the oil squirters, I use the newer cases with dual squirters rather then messing with the oiling/cases. Your ims is a turbo one I can see that. I also use the turbo one however I have found that the last of the 997 cup engines use the oil pump we use for turbo scavenging to scavenge the heads, so that ims will go in no problem. Glad to see your project back on track.

Tim

 

Looking good chad... With how that thing will rev I'd suggest using the the gt3 ims without the bolts which in your case could over time back out. The gt3 one is a better design. I've seen those back out on high powered built 997/996tt engines before- especially with lwf's....

 

Plus the gt3 tooth profile and pitch is more suited for higher rpm and will thrust load the tiny ims bearing less.

 

Yep the way it should spin up and rev that's what I'm saying. At this point it's better to be safer than sorry

 

Yes, the heads are from the GT Cup motor. Correct on the cam boxes are from a GT3. Cams are single lobe with GT3 Street markers. The intake and exhaust cams were custom made and ground with zero harmonic distortion. Lift is just under .550. The GT1 oil pump is a three index pump. It pulls from three areas one of which is directly off the heads. This particular pump costs about 10K. I post a pic of where the case is tapped for the pump. If you look closely the case is modified and the pump is ground to clear the crank.





The lower pic is the GT3 Cam Box, upper is 996tt. Our cams would have never fit in the smaller 996tt box.



Some of the specs on the rods:

BOLT CENTRES: 66.12
BUSH: 23.5 GROOVED
SHELLS: CLEVITE CB-1271
TYPE: 3/8 H-SECTION
B/E BORE: 53.967/53.980
S/E BORE: 22.02/22.03
CENTRES: 129.225/129.275
B/E THICK: 21.775/21.825
S/E THICK: 22.80/23.00
ISSUE: 01
CON ROD IS FULLY MACHINED
MACHINED AFTER ASSEMBLY WITH
SLAVE BOLTS
SMEAR BOLT THREAD AND SEAT WITH
MOLYBDENUM DISULPHIDE GREASE
BEFORE ASSEMBLY
GENERAL MACHINING TOLERANCE 0.2
GENERAL SURFACE FINISH 6.3
ARROW B141 (PORSCHE SP)
ROD CENTRES (mm): 129.25
STROKE (mm): 82.4
RPM: 8500
G/PIN MASS (g): ~
PISTON MASS (g): 414
TENSILE LOAD IN ROD 1.79 TON/F
PRODUCED BY PISTON
ACCN. @ MAX REVS = 17.82 kN
ENGINE:
OVERALL: 525g
ROTATING: 351g
RECIPROCATING: 174g
CALCULATED MASSES

 

Tim,

With the 4.3L, torque will come on a lot earlier than the 3.6L. We have decided not to build the car for top speed but rather track and street. The rotating mass of the crank, rods, pistons and pulley is extremely light. The stroke of 84.4 is a little more than we should have gone. If we were to do over we would have used a 82.4 mmmm stroke. The motor was built for quickness and response. The gearing from 1st through 6th as well as the complete tranny, clutch, RSR billet rear LSD custom front RAMP LSD and Motec traction control was designed to connect as much torque as possible to all four wheels and the ground. We doubt if we will exceed a 7600-7800 redline although the motor was designed to go much more.

 

That is one reason we went with the slightly smaller and a lot tougher (especially at higher rpm's) NASCAR Oval rod bear bearings.

 

Tim or Alex,

We are going with the Camero 105 mm throttle body. The bore is oval and we have found a quicker response and better acceleration at lower rpm's. Have either of you had any experience with this TB?

 

Never used one that big before

 

There are two Camero options avaible, 95 mm and 105 mm. We took the modified Cup intake plenum purchased from EVOMS awhile back, cut out the TB mount finished and re welded a mount that would accept the 105 mm TB.

 

I had the LS2 95mm TB with the jumper harness to our plug but never ended up using it. Why would you want such a big TB cjv? I do like the Idea of an oval one with metal intake.

 

Because it is oval ..... not round. Oval provides better low end, but size for size does not have as much maximum cfm as the round. To compensate at the higher rpm's you use a larger size when using oval.

The 95 mm could be sufficient depending on overall usage of the car.

 

Why not ITB's ????