2000 2V 6.8L in a Excursion, it lives between 8500 feet and once in a great while goes down to the mile high city of Denver.

9:1 compression is like 7:1 up here....11:1 would be like 9:1

Factory 9.2:1 static compression isn't cutting it....About 30% less power up here. I would like to buy a core motor and start building a replacement.

My thoughts:

1) just keep most things stock and have a custom ground set of cam shafts fabricated to raise dynamic compression 2 points or so. Or as high as it can go with a 9.2:1 static compression ratio.

2) Install new rods and pistons to raise static compression to about 11:1, keeping existing cams as they are hard to find in a custom grind.

3) E85 only with 11:1 pistons and custom ground cams to increase dynamic compression up to an efficient E85 range. Problem is E85 is not as dependable in the winter and custom tunes would just add more cost.

4) supercharger.....concept really as I really do not want to spend 6K-7k just to get the factory HP and TQ numbers. Kenny Bell or Whipple would be the only options as I do not care for high rpm turbos or belt driven centrifugal blowers. So it would have to be a custom kit which is really pricey.

I realize there are some that have issues with balance shafts when changing the weight of the rotating assembly, but I do not. I personally think that the inertia and harmonics of the rotating assembly are always there.....the balance shafts just offset what the "vehicle" feels. So changing the weight of the rotating assembly might make the motor shake a little little bit more.

Anyone have and advise?

 

Just getchoo some custom pistons and let her eat.

Messing with cam grinds seems like trouble.

Also have you researched machining the heads? A good engine machinist could do it and prepare you for related issues (timing chain, intake manifold fitting differently afterward, etc.)

 

So, which aftermarket pistons will attach to the OEM rods?

I was under the impression I would need rods that match pistons? E.G. floating vs pressed pins

 

You'd be impressed with a centrifugal, just because you're not in boost doesn't mean it's not adding airflow. Last time up the hills I was able to run OD/3rd(prior was 3rd/2nd) at 7K+ elevation towing 9000lbs. It would be less PITA than building a short block.

 

I agree with the previous post about centrifugal superchargers- it doesn't have to be high RPM for added power. Same with a small turbo. They are configured for your desires. And with a blow off/bleeder set at 3-5psi you can run it to the redline without much fear of breakage. Very expensive project though.

I don't think you have to get rods with the pistons. Just call JE or another good piston manufacturer and see what they say. (It's probably going to be$600+ so they'll be happy to talk to you)

And yet, machining the heads and/or decking the block is probably only $350... And it'll do the same thing...

 

$6000 for a supercharger is way more expensive than a few pistons and a rebuild. Is it worth it?

Would love a Paxton with a powerstroke intercooler though.

 

hp/$ the supercharger is a better option, NA is still NA. You'll spend at least $3K on high compression, for what 30hp at 4000rpm? 5psi will net you 100, I make 340/420rw with a procharger I used from a 5.4 setup and a 6.0L intercooler. The thing will get out of it's own way now without getting into boost, night and day. I bought it used I have $3700 into it.

 

I did not see injectors in Paxton's kit. So no intercooler no injectors what about a tune is it included?

 

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Just need to know if stock rods will work with forged aftermarket pistons?

 

No one here knows that answer. Contact JE Pistons (or whatever brand you like)

 

There is a plethora of used intercoolers, I paid 130. Same goes for 39lb injectors, $100. Don Lasota remote tuned mine since I had a wide band already, 150.

 

Just emailed Diamond Pistons for the answer. Pretty sure I will go with a rebuilt motor with 11.0:1 compression. Should get a little better fuel mileage and have much more torque.

At 7500 ft 11:1 is equal to 9.5:1; prefect. I could go to 11.5:1 for a 10:1 compression ratio if I wanted to use higher than 87 octane.

$880 for 10 brand new forged 11:1 pistons.

FYI 9.2:1 at 7500 ft is equal to 7.7:1!!! Yuck

 

Are you saying a 5.4 SC kit will have the right brackets to fit a V10? Getting interesting ! How do you control boost? I would want boost at low RPMs and extra blown off at higher RPMs.

 

So if you ever take your truck down to lower elevations, you will HAVE to run high octane fuel, right? If you have 11:1 pistons, could you safely tow heavy at lower elevations even with high octane fuel?

Just curious...