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-   -   4.7 boost question (http://www.jeepgarage.org/f196/4-7-boost-question-38128.html)

mandio23 02-29-2012 05:09 PM

4.7 boost question
 
How much boost can I push to a 4.7 with 10:5 CR?

Heelsparky0501 02-29-2012 05:28 PM

Re: 4.7 boost question
 
I personally wouldn't go over 8ibs with stock internals :)

FlyinRyan 04-02-2012 08:28 AM

Re: 4.7 boost question
 
Quote:

Originally Posted by mandio23 (Post 583972)
How much boost can I push to a 4.7 with 10:5 CR?

What kind of gas is available where you are located? What kind/brand of forced induction? Assuming US-grade 93 pump gas, and no meth, I would suspect no more than 4-6 lbs, you can run more with meth injection. I know Richie was running about 14 lbs on a HO motor but he was running meth.

Cams also play a role in this as well. Overlap is your friend in a case like this.

01grand 04-02-2012 10:13 AM

Re: 4.7 boost question
 
I'd be careful with a non HO motor, the HO's were built a little stronger I assume for a reason.

FlyinRyan 04-02-2012 11:36 AM

Re: 4.7 boost question
 
Quote:

Originally Posted by 01grand (Post 605575)
I'd be careful with a non HO motor, the HO's were built a little stronger I assume for a reason.

With 10.5 CR, he has aftermarket pistons, and some sort of rods other than non-HOs Searching through the OP's posts confirm this. So, not an issue here it seems. Avoiding detonation will be due to the high compression and IAT issues if he runs too small a F/I unit like the infamous KB kit.

scjeep4.7HO 04-02-2012 08:02 PM

You'll want a real intercooler unless you want to go through massive amounts of methanol. That's really pushing the limit with compression that high on boost too especially on pump gas. I assume you have had some engine work done and hopefully have forged internals.

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mandio23 04-07-2012 03:42 PM

Re: 4.7 boost question
 
Yes I had forged internals, water/meth, 12psi, running on c16 racing gas. Few weeks I ago I decided to push my 4.7 to its limit and added a 75 shot NOS. As a result piston/rod #1 flew through the oil pan and the engine block cracked in 4 different places. My engine was built back in 06 N/A and on boost for the last 6 months of its life.
My new engine block should be ready in about 3 weeks.
New 4.7 bottom end Mods
Manley forged pistons 8:1 CR bore at 3.70(+.040)
Custom Carrillo Billet rods
Total Seal rings
Clevite rod and main bearings
ARP Bolts
Forged crank (HO)

scjeep4.7HO 04-07-2012 03:50 PM

Hopefully you'll have better luck this time around. A 75 shot should not have done that, so I think something wasn't right.

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mandio23 04-07-2012 04:06 PM

Re: 4.7 boost question
 
Thanks,


after 6 years of hell, anything was possible...

FlyinRyan 04-07-2012 04:19 PM

Re: 4.7 boost question
 
Quote:

Originally Posted by mandio23 (Post 608893)
Yes I had forged internals, water/meth, 12psi, running on c16 racing gas. Few weeks I ago I decided to push my 4.7 to its limit and added a 75 shot NOS. As a result piston/rod #1 flew through the oil pan and the engine block cracked in 4 different places. My engine was built back in 06 N/A and on boost for the last 6 months of its life.
My new engine block should be ready in about 3 weeks.
New 4.7 bottom end Mods
Manley forged pistons 8:1 CR bore at 3.70(+.040)
Custom Carrillo Billet rods
Total Seal rings
Clevite rod and main bearings
ARP Bolts
Forged crank (HO)

What kind of power adder were you running? KB? Novi 2000?

Quote:

Originally Posted by scjeep4.7HO (Post 608898)
Hopefully you'll have better luck this time around. A 75 shot should not have done that, so I think something wasn't right.

Sent from my ADR6400L using Tapatalk

Quote:

Originally Posted by mandio23 (Post 608905)
Thanks,


after 6 years of hell, anything was possible...

Mandio, what was your fuel system like? Were you using stock rails?

mandio23 04-07-2012 05:51 PM

Re: 4.7 boost question
 
Quote:

Originally Posted by FlyinRyan (Post 608908)
What kind of power adder were you running? KB? Novi 2000?





Mandio, what was your fuel system like? Were you using stock rails?


Yes, Unfortunately I'm still running stock fuel system with WK 06 fuel rail. I'm running Novi 1000 with 3.25 pulley on this one.

FlyinRyan 04-07-2012 06:17 PM

Re: 4.7 boost question
 
Quote:

Originally Posted by mandio23 (Post 608938)
Yes, Unfortunately I'm still running stock fuel system with WK 06 fuel rail. I'm running Novi 1000 with 3.25 pulley on this one.

Why the WK fuel rail??? :confused:


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