When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The next logical step was for us to get inside of this LT4 and perform some valve train upgrades. We have been working on a CNC program for the new LT4 cylinder head for several weeks and just finished our first production set. I will include pictures/details below. Our camshaft selection was on the small side for our initial testing. Intake duration is low 220s. While this is a nice step up from the OE camshaft, it is still very small and drives AMAZINGLY well. We kept VVT in place, but removed DOD as we do not feel comfortable with DOD lifters in a high performance application.
All that being said, this round of modifications looks something like this....
Our previous best numbers were achieved with 11psi using the stock lower pulley and our 2.38 upper pulley. After the heads/cam upgrade we are producing 8psi across the board. Now that we know what kind of power we can produce without over spinning the blower we are having a larger lower pulley designed to see if there is any additional boost to be gained as some shops have reported.
Results on 8psi... 745RWHP/724RWTQ!!!!These #s are WITHOUT over driving the blower significantly
157RWHP/107RWTQ gain over stock baseline #s with 3 less psi across the board!!
Disassembly begins...
The LT4 cylinder head utilizes Ti intake valves, thus lash caps must be installed.
This is a shot of the inside of our blower "hat" with only 499 miles on the odometer.
The blower itself... There is a decent amount of oil around the edges of the blower that can be seen in this pic.
Here is a shot of the LT4 valley cover as well as the culprit for most of the oil you see in the supercharger. The next few pics will outline what I am describing, but basically GM placed an orifice in the valley cover that seals to an o ring in the supercharger and allows oil to be pulled from the valley into the supercharger.... Yes, there is a one way check valve so the blower does not pressurize the engine lol..
Underside of valley cover. We actually decided to weld this closed to avoid oiling the inside of the supercharger/engine. There is adequate PCV from the valve covers/dry sump to support over 1000RWHP.
The orifice in the supercharger itself.
Side by side fuel pump comparison ... LT4 Vs LT1 for those interested. The LT4 is significantly larger.
We only use the original Katech C5R Timing chains in all of our heads/cam & engine upgrades. To this date we have had ZERO failures.
Nice shot of the short block waiting for new cylinder heads.
GM LT4 oil pump. This has been slightly redesigned by GM as well in comparison to the LT1 pump. Most obvious is the purple cover.
Couple shots of the bottom end.... The oil pan requires removal when replacing the camshaft.
Intake runner of our new CNC LT4 cylinder heads.
VR dual spring upgrade. Notice the two different retainers being used. Install height is significantly different from intake to exhaust. The "do it your selfer" needs to take the proper steps when installing a spring kit on the LT4 head.
VR CNC LT4 Exhaust Port...
One more intake shot....
Verifying piston to valve clearance .... This is a critical step to ensuring a proper installation and reliability.
Almost ready to make some noise....
A couple interesting shots for those that haven't removed their front bumper cover yet. Notice the bumper support itself has large cut outs for increased airflow to the radiator just above the heat exchanger.
One more engine bay shot prior to the methanol system install...
Alky Control Methanol System Installed.
Vengeance Racing will continue to perform extensive R&D on the new LT4 to ensure we offer you the most powerful AND reliable combinations in the industry!
We would also like to thank Weld Racing and LG Motorsports for the new look on our C7Z!!! Traction is no longer an issue
Last edited by Ron@Vengeance Racing; 01-22-2015 at 03:20 PM.
You guys must be thinking about raising compression by milling the heads if boost is already that low. With a larger lower pulley you might now see over 11psi, which it seems to me you might want to raise compression to around 10.5 with a little bigger cam and then see what she puts down
You guys must be thinking about raising compression by milling the heads if boost is already that low. With a larger lower pulley you might now see over 11psi, which it seems to me you might want to raise compression to around 10.5 with a little bigger cam and then see what she puts down
We most definitely are. I will probably run this camshaft for a bit as it drives AMAZING and is making great power. I do see .030 off the heads and E85 coming our way in the VERY near future.
Yes and Yes guys... It is a bit pricey, but it is available. That being said, we have not confirmed that it physically fits under the LT1 manifold just yet. It looks like it will, but we have not had an opportunity to confirm.
I like the approach your team has taken...the Alky idea with a FI set up on pump gas is great; it will be even better once you introduce E85 with a bump in CR.
We most definitely are. I will probably run this camshaft for a bit as it drives AMAZING and is making great power. I do see .030 off the heads and E85 coming our way in the VERY near future.
Heck if I was going to run 8 psi I think I would bump the CR to 11:1
Hopefully that little blower can push 10-11 psi through that super efficient motor and get you to 800 rwhp
01-22-2015, 11:43 AM
Vengeance Racing C7 Z06 745RWHP/724RWTQ @ 8psi- LOTS of details inside....
