I'm starting this thread to gather information as I plan my engine build in the upcoming months.

I'm not exactly sure how far I want to go with the engine or how much $$ I want to spend on it as a non returning investment

I thought it would be helpful for myself and others to build a HP vs engine building guideline for everyone to get a broad idea of what is required. I will be the first to admit, I know VERY LITTLE about how far we can push these engines and what's required beyond the stock internals as I haven't broken anything yet at 855 WHP (knock on wood). My starting requirements below are nothing more than "my" best guess starting point. I will update each category based on peoples input who have more knowledge than I do!

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Mezger Engine suggested requirements (For long term reliability)

< 800 HP
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No engine modifications required (As long as torque is kept in check)


800-1000 HP
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connecting rods
pinned stock camshafts


1000-1300 HP
---------------
connecting rods
pinned stock camshafts
upgraded head studs - 12 mm (requires case mod)
upgraded head gaskets


1300-1500 HP
---------------
connecting rods
upgraded head studs - 12 mm (requires case mod)
upgraded head gaskets
upgraded cam shafts


1500-1700 HP
---------------
connecting rods
upgraded head studs - 12 mm (requires case mod)
upgraded head gaskets
upgraded cam shafts
ported Heads
oversized valves


1700+ HP
-----------
connecting rods
upgraded head studs - 12 mm (requires case mod)
upgraded head gaskets
upgraded cam shafts
ported Heads
oversized valves
3.8L - 4.1L displacement


I might be out to lunch on the HP the stock pistons/liners can handle but my understanding is that the factory Mahle pistons are as good as anything after market. Another thing I'm not sure of is head work vs cam shafts for our engines. Maybe the head/valves would come first? Yes, at the same time would be ideal, but for budget reasons, I've left them separate.

I also wanted to get input on connecting rods. Has anyone every proven a rod better than any other rod? IE: Pauter vs Carrillo? excluding say Pankl titanium for 5+ times the cost.

Thanks for any input that is given !!!


James

 

Cam will pick up more power revving to 7500 on stock valve train than revving higher with crappy stock cam profile (stock cams can be reground for reasonable price). Need forged pistons, stock are cast, need iron liners. Go with 12mm head studs regardless, at just over 1000whp, i blew the HG with raceware studs with oring'd sleeves.

 

Sean,
Thanks for the input. I added the upgrade to 12 mm to the list and o-ring to the heads. Do you know of anyone that has melted a stock piston? or cracked a stock liner? I'm wondering at what power it would happen.

 

it's the way you did your Orings - not the 10mm studs.

i would not do 12mm studs due to the casework involved.

 

Which shop/builder you recommend for the O-ringing ?

 

Tim did mine in my 996 and they held up to over 40 pounds of boost with 10mm studs.

 

What's his contact # ?

 

Marc,
Thanks for the update. 40 psi is a "bit" of boost I watched a Diesel rat rod on the dyno build 95 psi. It held until they tried to add straight nitrous into the turbo with no jet installed. Haha, I think it probably hit 4000 ft lbs before it blew a head gasket.

 

i've blown a head gasket in the 996tt at 35psi with no O rings and 10mm studs. With proper size and material O rings, ran more and more boost, zero issues with head-gaskets, no signs of pushing.

on a side note 997tt do have a better head casting than 996tt

 

My car was running 10:1 or 10.5:1 I dont honestly remember what CR was but was 10 or more. Boost levels mean nothing when it comes to cylinder pressure , running 40psi with no timing and CR info. You could run 100psi with no timing and have much less cylinder pressure than 30psi with all the timing.

In my case, increased boost level, higher than stock CR contributed to more cylinder pressure than the 10mm raceware were able to hold. My build was heat cycled and torqued to 60ftlbs, had orings, which I dont think did a damn thing here, the head lifted because something stretched, unloading it enough to blow a small piece of gasket out of #6 against the oil tank. Still has compression, doesn't misfire, just hear a small hiss like a leaf is stuck on the tire.

It's my 2c, not telling anyone what/how/where/who to use, I would just never bother running 10mm studs which have 53% less girth than the 12mm. The 12mm "can" be torqued to 130ftlbs, vs the factory rated 45 (60ftlbs according to Tim). I dont want to go back into my motor for something as stupid as a blown head gasket, and ill spend the extra 1000$ on the scale of things for piece of mind. VR6TEE isn't a budget build kind of guy, and I dont think he will start now with budget head sealing.

 

As far as machining goes for the 12mm studs, our machinist made a little tool that clamps to the adjacent head stud and allows you to center drill and tap the existing holes of the case, has little carbide inserts as guides for drill and tap.

http://sillyrabbitmotorsport.com/tmp/casedrilltap.jpg

 

Nicely done Sir

 

Sean,
Looks good! Are you selling the pieces or just using it in house?

 

I've heard some back and forth on the o-ringing. Can someone with some knowledge provide some input on pros / cons? Some builders do it and some don't.

 

Ive never had good luck with o-rings but my issues were coolant leak related and not cylinder pressure related. I heard a rumor that Anthonys engine does not have o rings. I think that is proof enough for me that we don't need them with the right studs/torque.