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4.7 boost question

10K views 16 replies 7 participants last post by  AV8WJ 
#1 ·
How much boost can I push to a 4.7 with 10:5 CR?
 
#3 ·
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.
 
#4 ·
I'd be careful with a non HO motor, the HO's were built a little stronger I assume for a reason.
 
#5 ·
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.
 
#6 ·
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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#7 ·
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)
 
#10 ·
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?

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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Thanks,


after 6 years of hell, anything was possible...
Mandio, what was your fuel system like? Were you using stock rails?
 
#15 ·
Sorry to bring back a dead tread…
I haven’t post anything in here in a while, about four years :D
My Custom forged engine still running strong but I did removed the Paxton Supercharger because I felt like it was limiting my engine and I decided it was time for a Turbo Upgrade. Unfortunately, the project was put aside for personal matters. Now, with my WJ Turbo project resurrected I will redo the suspension, tranny and reinforce everything that may break.
Currently doing my transmission-
NEW- 3400 billet stall, alto red clutches, deep oil pan, modified housing for extra clutches, seals, bearing, pump and all other internal parts. I’m only keeping my modified valve boy from my old transmission.
Let me know if I should update post as my project advances
 
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