Originally Posted by 98Z28CobraKiller

Doug, your answer above is like Obama's explanation of Healthcare Reform. Atleast tell us the theory.

Ron, please explain.

Also, if you want your cutouts to matter just put a direct port 250+ shot on there.

Using the lift logic with which I happen to agree, that other cam had too much for the AFR heads also as they typically max out around .590 lift.

Originally Posted by Ron@Vengeance

Its been quite an interesting week at Vengeance Racing. Allngn_c5 made the trip down from Michigan to make some changes to his current combination. Allngn_C5 has a 2000 FRC Vette with a 402 LS2 and supporting bolt ons.

The goal of this build is to increase drivability while increasing overall horsepower without sacrificing bottom end torque.

Changes to be made are:

Baseline vehicle upon arrival
Installation of Racetronix fuel system
Removal of LGM 1 3/4 Longtubes
Installation of American Racing 1 7/8 Longtubes
Dyno vehicle to verify changes
Remove AFR 205 cylinder heads
Install Trickflow 215cc cylinder heads
Dyno vehicle to verify changes
Remove LG G6X3 camshaft
Install Vengeance spec custom camshaft
Dyno vehicle to verify changes

When I arrived at the shop Monday morning Doug was already in the parking lot waiting for us. We got the shop rolling and took Dougs vette to the dyno for a baseline prior to starting the modifications. Initial numbers were 494.85/484.17...


After getting baseline #s it was time to hit the rack and swap some parts. Doug wanted to add a Racetronix fuel system to his car to ensure he wasnt going have any fuel pressure issues in the future. We did verify fuel pressure on the dyno during the baseline and fuel pressure maintained 58psi with zero knock retard showing on the log file.

After the Racetronix was installed we removed the LGM 1 3/4 longtubes and replaced them with American Racing 1 7/8 longtubes. Both systems are using NON catted X pipes and bolting directly to the LGM Big 3 exhaust (VERY nice piece btw!!!)

Now its time to go back to the dyno to see what changes the header swap made. Initial pull was 511.37/491.30... This is an overall gain of 16.52RWHP and 7.13RWTQ.. The graph below tells more of the story though. The American Racing headers actually produce more torque in the lower RPMs, but they show a decrease in torque Vs the LGs at around 3750 to 4500rpm. After 4500rpm the American Racing longtubes pull from the LG 1 3/4s by an average of 10/10.

Now that the header swap has been verified it is time to remove the AFR 205cc Cylinder heads and install TrickFlow 215cc Cylinder Heads. The AFR heads had a combustion chamber of 58.5. The Trickflow heads were milled to 59cc. The Trickflow heads were also opened up to a 4" bore to match the shortblock. Yella Terra rockers were installed to replace the OE rockers and 7.500 pushrods were installed to replace the 7.400s used with the AFR combination. No other changes were made at this time. Results were 539.39/507.39. This is a gain of 28.02RWHP/16.09RWTQ



The results speak for themselves. While the TFS heads were optimized for the 4" bore the power gained is quite impressive comparing two extremely high quality cylinder heads. You can see where the large displacement engine wanted the additional airflow of the 215cc head.

Now its time for the cam swap. The G6X3 had been performing extremely well up to this point, but Doug wanted to see if he could get better street manners and possibly improve power even more. So we removed the G6X3 and installed a custom cam. We opted for slightly more duration/less lift/wider LSA... The camshaft selected was 239/243 .623 /.623 113+3... Compared to the LG camshaft we added 4* of duration to the intake/1* to the exhaust.. Took almost .30 lift off of the intake and widened the LSA by 2*... Results are quite interesting for so many different changes going on with the camshaft. Results are 541.14/505.36... That is a PEAK gain of 1.75RWHP peak and a PEAK LOSS of 2.03RWTQ. Notice the powerbands are very similar thru most of the curve with the Vengeance cam actually picking up 10rwtq under the curve at points.


Overall drivability has been improved and there is a noticable difference in valvetrain noise as well. The TFS/Yella Terra/Vengeance spec cam seems to be much quieter under the hood Vs the AFRs with shimmed springs/G6X3 camshaft/stock rockers.

Here is the graph showing the baseline #s as the car came in with the final #s as the car left.


Actual gains are 46.29RWHP and 21.19RWTQ

After all of the changes were made and all of the testing was done we added the following items before the car goes back to Michigan

Catch Can
Metco Breather
Flow Matched/Balanced customers 42lb/hr fuel injectors
DMH dual electric cutouts. Doug saw these on another customers car and thought they were really cool. Unfortunately they did not pick up a SINGLE RWHP over the LGM Big 3 exhaust. The LGM exhaust lived up to its name and performed beyond our expectations.

Testing is over and Mike is out finalizing the tune. I would like to say that Doug was present for EVERY dyno pull/modification. We allowed Doug to be a part of all of the work as to give him first hand experience and give him the confidence to know exactly how his car is performing and where his money is being spent. It actually worked out to our benefit because Doug saw our grill outside that we use on dyno days and he has cooked us lunch everyday since he has been here

Thanx again Doug for making the drive to Vengeance. We appreciate all of the good cooking and it was cool hanging out with you as well!!!


Idle Clip

http://www.youtube.com/watch?v=ab_NtwqZh3o


Drivability Video # 1

http://www.youtube.com/watch?v=e7kr4NOpMzk

Drivability Video # 2

http://www.youtube.com/watch?v=2_M8TIXETwI

WOT Pass

http://www.youtube.com/watch?v=Og_FMQF-72g