My 2002 5.9L Magnum motor is gone. Yup... I sold it. Why? Math. I added up the list of upgrades I wanted to do in order to make that motor produce the power I wanted and said "Dude! Seriously?!" Then, I happened to realize how my target HP/TQ compared to a stock HEMI. That's all it took. Things just didn't add up to keeping that '02 engine. So I sold it. ...and, it's a good thing I did. Turns out, just like every other 5.9 out there, it had cracked heads. Admittedly, I was going to replace the heads, but that's beside the point since the replacements I was going to get lead to the high cost of upgrading that engine.
Anyway... I have acquired a 5.7L HEMI along with the attached 5-speed automatic NAG1 transmission out of a wrecked 2007 Chrysler 300C. I'm upgrading this engine as well... But the power potential is so much better on the HEMI than the Magnum motor.
Then, I began to research making that HEMI and NAG1 work in my restomod. ...gulp. So... I started to formulate a plan for making it run the way I wanted. Thanks to a few good resources, I have a very good start on getting everything I'll need to finish this truck. But, as sometimes happens, things I have worked long and hard on will have to be completely re-worked.
I have decided I want to use the factory computers to control my HEMI and transmission. I want to retain the Anti-lock Braking System. I want to retain the Sentry Security system. I also want this 1950 Panel Van to handle like it's a 2006 Charger SRT (well... like a 2006 Charger SRT with a gigantic turtle shell maybe! It's hard to make a van feel like a car when you consider body-roll.)
To that end, I picked up a second-hand insurance auction roll-over car as a donor for the suspension cradles, shock mounts and braking system. The first owner stripped out all the interior. I stripped everything else out of the car and sold what I could. I traded the 3.5L engine for a full set of computers (ECM, TCM, PCM, etc.), wiring, instrument panel and ignition mechanism with sentry security module from a 2006 Charger R/T. Oh... The front & rear brake rotors & calipers under my 2006 Charger SXT (donor) had been swapped for those from an R/T. I also have the correct gear ratio in the rear end.
I am at the point where I need to decide whether to "just" swap the suspension from the Charger over to the Panel Van or whether to graft the entire chassis to the under-side of the Panel Van. Hmm... World's first Panel Van body swap onto a uni-body chassis? Either way, I know I need to upgrade the springs and anti-sway bars to handle the extra weight (and different weight distribution) of the Van.
While considering that... I've been thinking about how this truck should accelerate. I love the way my Wife's '08 Ram accelerates.
Her truck has:
- stock 5.7L HEMI
- 3.92:1 differential gears
- OEM sized (275/60R20) tires that measure 33" tall according to Tire Rack
- a first gear that's at a 3.00:1 ratio
My Panel Van has ('06 Charger R/T w/SRT8 wheels & tires):
- stock 5.7L HEMI
- 2.82:1 differential gears
- OEM sized (245/45R20) tires that measure 28.7" tall according to Tire Rack
- a first gear that's at a 3.59:1 ratio
So doing some creative math here... The stock '08 RAM has a final drive ratio in first gear ("gear ratio"x"ratio of 1st gear") of 11.76. The Panel Van's final drive ratio in first gear is 10.1238.
If you divide the tire height by the final drive ratio, then you can compare the two vehicles to get some sort of idea of how the torque is transferred to the road (and to my seat
). The RAM gets a "tire height" to "final drive" ratio of 2.806 while the Panel Van gets a 2.835.
All this to say... The '08 RAM should feel a little more torquey than the Panel Van. So... How do I change that? Two options here (same two options car guys have been playing around with since the birth of the hotrod): Tire Size; and Gear Ratio.
If I trade up to 3.07:1 rear diff. gears, then my "tire height" to "final drive" ratio would on the Panel Van would be 2.604. Daddy Likey! Alternatively, I could change the tire size to a 245/40R20 (27.7" tall) to yield a 2.736 "tire height" to "final drive" ratio... But those tires are more expensive and, frankly, I plan to go through some tires with this fun truck