LT4 Short Block for Boost Proper Build?
10-23-2016, 06:37 PM
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LT4 Short Block for Boost Proper Build? So my engine is toast...
Long story of 13 years to get the car done and 2 years to tune the engine setup. Lots of steps backwards and the latest was diagnosing too much crank case pressure and the compression test results are TERRIBLE.
1-145psi
2-215psi
3-220psi
4-140psi
5-210psi
6-145psi
7-90psi
8-210psi
4 bad cylinders!!!!! I have only put about 1/2 a tank of gas through the engine so it was either bad when I bought it or my one pull that hit 13 psi killed it (FYI the leanest AFR on that pull was 10.5 for a split second but mostly in the 11/12 range). I would not have thought 13 psi would destroy the engine, I put a different pulley on after that pull to reduce the boost to hopefully a max of 10-12 psi. It wasn't the best engine to boost but I thought it would live fine on the street, I guess not.
Here is the info on the engine as I bought it from SDPC back in 2005.
-385 ci
-Ported & hand polished LT4 heads, Titanium retainers, SD1007 valve springs, and Manley Stainless Valves
-Block is "0" deck, 4.040 bore, clearanced for stroker crank, and 4 bolt main
-Port Matched LT4 intake
-Zero balanced rotating assembly: Callies Magnum 4340 Crank, Manley 5.7 Rods, JE Flat Top pistons, and file fit ring set
-10.4 CR
-Moroso 7 qt pan, Speed pro high volume oil pump, GM extreme duty timing set
-Manley Push Rods
-GM LT4 Hot Cam
-Engine made 485 HP @ 6300RPM/467 lbft @ 4600 naturally aspirated
I added the following
-Custom 12 rib F1A Procharger
-Large front mount intercooler
-24x conversion
-60lb injectors
-255lph in tank with Kenne Bell BAP
-Full SS Headers and custom 4" exhaust
What changes would everyone suggest to build it the right way for a 12-14 psi F1A Procharger?
-Proper and best Rings, gaps ets?
-Best pistons for a max of 14/15psi of boost?
-With a goal of 700 RWHP what CR (9.0/9.5/10.0)?
-Best cam for 14/15psi of boost
-Best head gaskets for boost
-Should I upgrade fuel pump (350 lph in tank or dual 255's)
-New fuel lines or will stock support 700 RWHP?
-Will 60 lb/hr injectors support 700 RWHP?
-Get the block work done locally in the North West or who are the good LTx engine builders now?
Long story of 13 years to get the car done and 2 years to tune the engine setup. Lots of steps backwards and the latest was diagnosing too much crank case pressure and the compression test results are TERRIBLE.
1-145psi
2-215psi
3-220psi
4-140psi
5-210psi
6-145psi
7-90psi
8-210psi
4 bad cylinders!!!!! I have only put about 1/2 a tank of gas through the engine so it was either bad when I bought it or my one pull that hit 13 psi killed it (FYI the leanest AFR on that pull was 10.5 for a split second but mostly in the 11/12 range). I would not have thought 13 psi would destroy the engine, I put a different pulley on after that pull to reduce the boost to hopefully a max of 10-12 psi. It wasn't the best engine to boost but I thought it would live fine on the street, I guess not.
Here is the info on the engine as I bought it from SDPC back in 2005.
-385 ci
-Ported & hand polished LT4 heads, Titanium retainers, SD1007 valve springs, and Manley Stainless Valves
-Block is "0" deck, 4.040 bore, clearanced for stroker crank, and 4 bolt main
-Port Matched LT4 intake
-Zero balanced rotating assembly: Callies Magnum 4340 Crank, Manley 5.7 Rods, JE Flat Top pistons, and file fit ring set
-10.4 CR
-Moroso 7 qt pan, Speed pro high volume oil pump, GM extreme duty timing set
-Manley Push Rods
-GM LT4 Hot Cam
-Engine made 485 HP @ 6300RPM/467 lbft @ 4600 naturally aspirated
I added the following
-Custom 12 rib F1A Procharger
-Large front mount intercooler
-24x conversion
-60lb injectors
-255lph in tank with Kenne Bell BAP
-Full SS Headers and custom 4" exhaust
What changes would everyone suggest to build it the right way for a 12-14 psi F1A Procharger?
-Proper and best Rings, gaps ets?
-Best pistons for a max of 14/15psi of boost?
-With a goal of 700 RWHP what CR (9.0/9.5/10.0)?
-Best cam for 14/15psi of boost
-Best head gaskets for boost
-Should I upgrade fuel pump (350 lph in tank or dual 255's)
-New fuel lines or will stock support 700 RWHP?
-Will 60 lb/hr injectors support 700 RWHP?
-Get the block work done locally in the North West or who are the good LTx engine builders now?
