You could try phoning Alan Zini at Dragon in Colchester UK (01206 865444). He fitted ARP bolts to my car on Monday. The downpipe needs to come off to get the sump off, and some people say you need to let the sump sealant cure overnight. Sorry dont know the torque settings, but Alan will.
Yep, you need to take the sump off and can change them from underneath, don't know the torque settings. Could provide you with the torque for the standard bolts, but I suspect that the ARP bolts will have different torque as they are a different material.
Fitted ARP big end bolts 2 my own VI , although basically straightforward there r a couple of potential problems 4 the unwary.
Installing these without a 2 or 4 post lift wud not b advisable.
The downpipe , sump and various other bits and pieces require removal , the sump is attached with special sealing compound , no gasket , and requires care 2 remove without damage.
The factory bigend bolts r a drive fit in the conrod , so require drifting out , so the conrod has 2 b supported against the cylinder block with a suitable piece of wood or hard plastic dowel.
The ARP bolts will require careful pulling into the rod with a slide hammer as they r an interference fit , but they must b pulled in square as the head that rests against the rod fits in a particular position.
The torque settings 4 the bolts r given in the install notes packed with them , together with a special assembly lube.
The sump will require resealing with a special Loctite product at about £15 per tube. This needs 2 cure 4 at least 12 hours.
If u feel confident with yr skill level go 4 it , but consider that if 1 fails , goodbye engine
No , the interference fit is 2 close 4 that method , also heat/freeze wud b way 2 awkward.
I used an adaptor made 2 thread onto the bolt , the slide hammer then attaches 2 the adaptor , with the rod firmly held against the crank this works like sex , and there u have it
More boost pressure creates higher combustion pressure hence more power , but it also creates a higher bending force in the con-rod , this force is seen by the big end eye so the bolts r subjected 2 a higher tensile load .
Comparing the ARP bolts with the factory bolts was interesting , the factory bolts r not in the same class.
-The maximum strain on them is actually when the piston is at TDC...think about it, when are the bolts going to stretch, not when the piston is pushing down
-The strain basically goes up by the square of the rpm or something similar
-In the latest motors the bolts are only 8mm...tiny, used to be 9mm
-The bolts are at the bottom end of the strength range offered by ARP
-The chances of them having a flaw which causes them to fail when they shouldn't, is very low due to good QC. The probability of failure may or may not be better than the OEM.
So in my opinion:
If you are tuning for midrange torque and not doing big revs then the only reason to fit them is because they may have a lower defect rate than OEM
If you are tuning for power and doing big revs (and raising the rev limit) then consider them but a better idea would be to fit rods that have bigger bolts as their is a limit to the ultimate strength of such a small bolt.
I friend of mine has soft tuned engine on his EVO VI. He only modified:
ECU Walbro TDD (very rich)
His engine car has !!!!2 bar!!!! peak and 1,8 bar flat!!
I suspect that he has 380-400 HP http://www.lancerregister.com/graphics/embarassed1.gif border|EQU| 0 align|EQU| absmiddle >. He hasn't the ARP CONROD bolts!! His engine runned for 10000 Km with this configurations.
Is he lucky or the worst is to come?
The max tensile load thru RPM is as u say at TDC , however with higher boost as I said above the force on the power stroke causes a larger load on the bigend bolts thru a bending load on the rod.