Need opinions

[Goatman91]

Ok spark plugs, iridium or should I just stick with the copper core? Headers, shorty or longtubes?
Coil packs, I'm thinking about switching to mds coil packs is it worth the money? Ever since I put the 35s on my trucks feels real sluggish compared to a couple others with the same motor.maybe re gear from 3.92 to 4.10 idk. I'm sure headers would help too. Any suggestions?

 

[xrsman]

Regearing from 3.92 to 4.10 isn't worth the difference. If you're going to regear go to 4.56's.

Longtube Headers.

Maybe try a tuner before the gears and get a custom tune done?

 

[Goatman91]

I have a trinity with the hemi fever tune. I like the tuner but not very impressed with hemi fever.

 

[Hemi450hp]

Copper Plugs
Longtube Headers
Don't waste your money on the MSD coils
Not worth the swap from 3.92's to 4.10's

And have you sent logs to Hemifever yet? Nobody runs slower with a Hemifever tune over the canned Diablo tunes unless it is extra tire spin that is slowing down the overall time. If you have not sent him datalogs yet, then you need to do that ASAP. If you have done that, then I would reload the tune and be very careful to follow his instructions when it comes to selecting the correct backup file. If you select the wrong file, then it will reload a stock tune instead of the new custom tune. That can very well explain why you did not see an improvement over the Diablo canned tunes.

 

[Goatman91]

Ok I'll probably just reset the tuner and try again. IM about to send Sean an email. Any suggestions on coils or are the oem coils fine? What about 4.56s. I saw some on your site, I do have to care about milage slightly so will I take a bad hit switching? I get about 14 with a 6 inch lift and 35s. If I put headers I mine as well put a bigger throttle body as well I imagine?

 

[Hemi450hp]

The MSD coils are just stock replacements, so they look great, but don't offer any extra spark or performance. I would just keep the stock coils and throw a fresh set of OEM NGK plugs in there.

As for the gearing, are you 2wd or 4wd? If you are 4wd, then doing a 4.56 swap is going to easily run you $3000+. If you are 2wd, then it runs about $930 in parts because you would need gears and a new machined rear LSD. I run 4.56's in my crew cab daily driver with only 32" tires and still get about 17mpg on the highway at 70mph. At 70mph, I'm turning 2400rpms.

And the throttle body would be worthwhile after adding headers. You should pick up another 15hp/tq from the TB with you already having the other supporting mods.

 

[Burla]

Those 3.92's should be plenty fine for 35's, maybe get a tuner and change the tranny shift points. Go to 4.56 you will suck gas like a dragster.

I get 14mpg just with a level and 3.55's, I don't even want to know the bad news with 4.56. Maybe I need to do some shopping at Moes to get my mileage up.

If you drive a lot of city miles, may turn out ok, a lot of freeway miles though, the mpg will suffer.

 

[Ratket]

With 456 mds will activate more often.

 

[jasonw]

If you want to go iridium, try the Denso TT plugs. I have a set in my garage waiting to go into the truck the next free weekend I have (40k on originals so far). I've read really good reviews from a few Charger/Challenger forums on the Denso TTs for our Hemi engines.

However, don't do it for performance. There isn't any difference. It does let you go longer between plug changes, which is why I am doing it.

 

[Goatman91]

I think I'll just stick with the copper core. Irritating to have to change them every 30k but whatever it's something to do. I finally got my hemi fever tune working correctly and now I notice alot more pep in its step. I still think I'll upgrade to a 87mm tb with some longtubes, I know I lost alot of low end with the lift and tires. Matt, why 3k for 4wd? You can't just swap out the ring and pinion?

 

[Ratket]

some one decided they needed to be welded in I believe... so no such luck on just swapping them out.

 

[Hemi450hp]

Your front ring gear is welded onto the carrier, so you would have to replace the entire front carrier with 1 from an 09-11 as well as the front driveshaft, and then buy the aftermarket 8" front gears and install kit.

In the rear, nobody makes a 4.56 that bolts right up to the 9.25ZF diff, so you would need to purchase the Modern Performance Engineering machined rear diff, rear 9.25 gears, and install kit. In the end, it becomes a very expensive swap.

 

[Goatman91]

To hell with that then. I'll just stick with 3.92