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Discussion Starter · #1 · (Edited)
Bringing the LX Hemi to life

I have enjoyed enabling the engine, transmission, and suspension of my sweet Hemi to realize more fully their performance potential and to perform as I, the driver, choose. Every performance mod has removed yet another item from the list of observed driveability flaws and performance shortcomings with my '05 LX Hemi.

The K&N Typhoon intake and Jet Performance throttle body spacer eliminated nearly all throttle lag, with the Typhoon adding a throaty accent to accelerations. Adding the stage II Jetchip removed all remnants of throttle lag, firmed up the tranny, reduced shift lag, and moved my shift point further up the rpm scale. This mod alone, by bumping up both tranny & engine performance, gave me the new-found ability to hang the rear end out at will when cornering. Many months and 6000 miles later, that ability continues undiminished. Mileage increased by 2 to 3 mpg, city & highway, respectively, which more than compensates, cost wise, for the need to run 91 octane fuel (or higher - performance increase is proportional to octane rating).

I added the Magnaflow cat-back exhaust in early September and picked up high-end performance and a beautiful exhaust note. Mileage increased by 1 mpg.

The GSM torque modulation & fan mod has removed any remaining complaints with the transmission, and immediately moved my shift points back up to where the jetchip initially had them. Every shift at WOT now occurs at a totally predictable 5500 rpm, precisely, each & every time. Partial-throttle shifts appear to hold each gear a bit longer. Lag in any given gear is gone completely, and kick-down to a lower gear has been speeded up appreciably. The fan mod, in conjuction with a cooler thermostat (both are essential), has killed heat soak.

At the track in early September (Phoenix Firebird: 1,243’ MSL, approx 4250' PA, 95 degrees F.) I repeatedly hit the rev limiter doing pre-run burnouts. Full torque launches at 30 psi rear tire pressure resulted in excessive wheel spin throughout first gear and part-way through second gear, resulting in ETs in the 15s, but decent speeds. Lowering the stock rears to 22 psi helped control wheel spin. Best overall run of the evening, however,13.85 at 101.98 (adjusted), with a .065 R/T, occurred prior to lowering my tire pressure, but with a very mild torque launch. By midnight air at the track had cooled down to 90 degrees F. I’d hung around waiting for this relatively cooler air to give me the outright 14.5 ET I'd set as my personal goal for that hot desert night, but my heat-soaked motor simply couldn’t produce it.

Unhappy with heat soak, which, due to the hot 203-degree stock thermostat, even the GSM fan mod couldn't prevent, I installed a nominal 180-degree thermostat, which actually cooled to an indicated 174 degrees on EVIC. The combination of the GSM fan mod and a colder tstat is - as the current slogan says - priceless. At my most recent track event, with multiple runs - several of which were back to back with less than 10 minutes between runs - coolant temp as I prepared to stage was always in the 160s.

This provides very consistent runs, with times varying only with changes in ambient air temp. Heat soak is now essentially non-existent.

My Hemi was tested on the dyno and the track at GIFO3 in Sacramento. Rear wheel horsepower was just shy of 290 hp, and rear wheel torque was just over 300 ft/lbs. Best run on a warmish evening was 14.0 at 98 mph, unadjusted for a density altitude of around 800 feet if memory serves.

I have continued to test cooler thermostats. The 160 degree tstat is the ideal tstat for the track. I've had no issues running it on the street - if I avoid using the fan mod, temps will run as hot as with a 203 around town. But if on the highway for any significant time in cool ambient temperatures it runs cooler than I am comfortable with. Long-term the 170 is the best overall choice for me - it is my year-round daily driver. The 160 will be installed each track day.

My most recent mod, KW V2 coilovers and Hotchkis Sport anti-sway bars, has brought my Hemi to near perfection in concert with my prior mods. I'm using the factory suggested initial rebound damping setting of 2 turns out, front, and one turn out, rear. Performance at this suggested initial setting is so flawless that I'm in no hurry to change anything anytime soon - I have absolutely flogged these KWs and the Hotchkis bars and had not the slightest complaint with or from them.

On tight, twisty, mountain roads the total combination of a jet chip, cooler thermostat, GSM torque & fan mod, and KWs and Hotchkis sways was unbeatable. The superb driveability that I've always pointed out that the jet chip provides by removing virtually all throttle & tranny lag, coupled with total disabling of ESP, the fan mod keeping coolant temperatures at or near my cooler thermostat's temp for sustained maximum horsepower delivery even when I was flogging the motor, and a superior suspension was an unbeatable combination. In these extreme conditions, where one is going from wide open throttle (WOT) to ABS chatter to WOT, etc., faster than you can read about it, my car was fully a match for the stock SRT8.

The additional power generated by the Jet chip is certainly a factor as well, but its most appreciated benefit in these tight conditions was the instant response the chip enabled from both engine & tranny.

Words cannot describe the exhilaration I experience seeing all systems, placed, at my command, to optimum performance parameters, working in a flawless, overpowering, synergy...

What I meant to say is that my total performance package really kicks some serious butt. :wink:

Summary:

1. The LX-based Hemi's in stock form are very capable vehicles and get the job done well. Most of the noticeable driveability flaws and performance shortcomings which frequently irked me about my stock LX, and which have essentially disappeared because of my mods, are absent at WOT and thus are masked while on the dyno and at the strip. Day to day driveability improves tremendously with mods, the Stage II Jet Chip in particular.

2. If you enjoy being able to truly set your hair on fire--hang the rear end *way out* at will on corners, enjoy hearing a Hemi's inimitable howl from *both* ends, and don't mind occasionally seeing some rubber converted to good old-fashioned tire smoke--the mods are the only way to go. The fun factor goes way up.

3. I'd to it all again—in a heartbeat.

 

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Th owls haunt me as well

I'm getting there Jim. (as you know)
MOPAR CAI
Magnaflows coming next week
GSM "thermostat" coming next week or so

BTW, I danced last night and now I'm paying the fiddler. (I'm 57)


Meister said:
I've truly enjoyed modding my sweet C. Every mod, whether performance or appearance / function, removed another item from the very short list of complaints I've had with my '05 LX Hemi. I'll only address the performance mods here:

The K&N Typhoon intake and Jet Performance throttle body spacer (both were installed at the same time, so I can't address the contribution of the TB spacer alone) eliminated nearly all throttle lag, with the Typhoon adding a throaty accent to accelerations. Adding the stage II Jetchip removed all remnants of throttle lag, moved my shift point further up the rpm scale, and gave me the new-found ability to hang the rear end out at will when cornering. One month, and nearly 2000 miles later, that ability continued undiminished. The WOT shift point, however, did get reeled in slightly by the MDS, with shifts typically occurring at 5400 rpm, occasionally as low as 5300 rpm. Mileage increased by 2 to 3 mpg, city & highway, respectively.

I added the Magnaflow cat-back exhaust last week and picked up high-end performance (don't ask) and a beautiful, to my tin ears, exhaust note, with no discernable change in mileage. I may need to add another set of resonators, though, as my wife is less taken with the “noise” factor than I, and they do get appreciably louder with time & use. And tonight, for the first time, I experienced MDS “blubber” with the Magnaflows which other owners running aftermarket exhaust systems have commented on. Tapping the AutoStick and moving the tranny out of Drive “cures” it, but out on the open road I’ll want MDS active, and without the blubbering. Thus the MFs are an open item. Richard, are you out there?

Another mod I've only recently made (again, don't ask) has removed any remaining complaints with the transmission, and has moved my shift points back up close to where the jetchip initially had them. Every shift at WOT now occurs at a totally predictable 5500 rpm, precisely, each & every time. Partial-throttle shifts appear to hold each gear a bit longer. Lag in any given gear is gone completely, and kick-down to a lower gear has been speeded up appreciably.

At the track recently (Phoenix Firebird: 1,243’ MSL, approx 1500' PA, 95 degrees F.) I repeatedly hit the rev limiter doing pre-run burnouts. Full torque launches at 30 psi rear tire pressure resulted in excessive wheel spin throughout first gear and part-way through second gear, resulting in ETs in the 15s, but decent speeds. Lowering the stock rears to 22 psi helped control wheel spin. Best overall run of the evening, however,14.608 at 96.67 (.065 R/T), occurred prior to lowering my tire pressure, but with a very mild torque launch.

By midnight air at the track had cooled down to 90 degrees F (YGBSM). I’d hung around waiting for this relatively cooler air to give me the magic 14.5 ET I'd set as my personal goal for that hot desert night, but my oft-worked & heat-soaked motor simply couldn’t produce it. Next time I'll probably show much later in the evening.

Lesson learned the following day (I'm 62, BTW, and hadn't been to the drags in four decades): It's much harder to soar with the Eagles the next day when you've been out hooting with the Owls the night before. :)

Note: Special thanks go to BMWDON for the great price on the stage II chip, Typhoon & throttle body spacer package, to TByrne for the great GB price on the Magnaflows, and to GSM for the uh, errrr, ummm, oh yeah!...for the *thermostat* :). Thanks mucho, guys, for helping me have this much fun, period, and especially for enabling it to be done for around half of MSRP.

Summary:

1. The LX-based Hemi's in stock form are amazingly capable vehicles and really get the job done well--I bested the time of a near-stock 300C last night by only the narrowest of margins (his only mod, TMK, was to remove the stock CAI's baffle).

However, comma, if you enjoy being able to truly set your hair on fire--hang the rear end *way out* at will on corners, enjoy hearing a Hemi's inimitable howl from *both* ends, and don't mind occasionally seeing some rubber converted to good old-fashioned tire smoke--the mods are the only way to go. The fun factor goes way up.

2. You can't realistically compare your Hemi to another's--each is created different. Mine was no slouch (it would probably take a true lemon for one to be considered such, realistically), but it probably fell in the mid-range of performance, at best, among 300Cs as delivered. In its stock form it fell short of a number of performance marks other C owners had posted over the past year for their stock Hemis.

3. I'd to it all again—in a heartbeat!!
 

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Meister...
I went to Flowmaster on my exhaust,loved the sound.
However, Fiance' had a little difficulty with it - just a bit loud.
I added a 12" glasspack old "cherry Bomb" style muffler,welded on my 4" Chrome exhaust tips.
Still have the rumble at idle,throaty grumble upon acceleration,and
"Turn the Beast Loose" sound at WOT.
Labor, welding = $60
2 "cherry bomb" glass packs = $40
a big "Thank you Darlin' " = Priceless
........
 

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Discussion Starter · #4 · (Edited)
Magnaflow noise dilemma

Lik2race said:
Meister...
I went to Flowmaster on my exhaust,loved the sound.
However, Fiance' had a little difficulty with it - just a bit loud.
I added a 12" glasspack old "cherry Bomb" style muffler,welded on my 4" Chrome exhaust tips.
Still have the rumble at idle,throaty grumble upon acceleration,and
"Turn the Beast Loose" sound at WOT.
Labor, welding = $60
2 "cherry bomb" glass packs = $40
a big "Thank you Darlin' " = Priceless
........
Thanks, Lik2race. Looks like the perfect solution with your flowmasters. My magnaflows already use the space you mentioned with resonators (see http://www.magnaflow.com/02product/...p?zone=American&SID=4Chrysler&id=236&cat=300C).

Magnaflow (Richard) has suggested an internal modification to the main muffler if a tone down is required.
 

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Discussion Starter · #6 · (Edited)
Magnaflow noise dilemma

chasb said:
It the MDS noise really that bad with the Magnaflows??

I've heard that it pings or something?
No pinging noted, Chas, but the sound certainly isn't pleasant. I suppose it's that with a louder, aftermarket, exhaust we're literally *hearing* a four banger when she's in MDS mode.

At present we're keeping the MFs as installed.
 

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That's why I love the Borla 3.5 inch system, just enough noise to know it's not stock but not enough to drive you nuts. :wave:
 

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you guys would hate my exhaust then :biggrin: two 14 inch long borla mufflers and 2.5" pipes ...no resonators :wave:
 

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Discussion Starter · #9 ·
Update to comment on MF loudness

Magnaflow's ace Mopar designer, Richard, is, indeed, looking at a way to tone the MFs down a bit for me. I'll continue to update this thread with any particulars.
 

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Still waiting for mine to be installed

They are sitting here in the box and giving me no pleasure at all at the moment.

I would be interested in hearing more on the DB issue, though. I don't want the blubber either.

Chas


ps Thanks Meister for another informative write up, if I didn't already say it.
 

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chasb said:
They are sitting here in the box and giving me no pleasure at all at the moment.

I would be interested in hearing more on the DB issue, though. I don't want the blubber either.

Chas


ps Thanks Meister for another informative write up, if I didn't already say it.
Apologies to Meister for some plagiarism.

Bringing the LX Hemi to life My life, my mods

--------------------------------------------------------------------------------

Here is my updated version of the quest for the perfect LX.

First mods were rims and tires. I do this to all my cars. (Zinik Z-12 Mazotti black 20 x 9 with Goodyear F1 supercars 245/45 ZR 20's all around.) Incredible difference in performance . Car handles like a slot car compared to the stock contis.

The MOPAR CAI I installed immediately took care of throttle lag and made my car shift much crisper than before. The sound is awesome as well.

After that, the Magnaflows came on, courtesy of a T Byrne group purchase (thanks Tommy). Made me feel like I was back in the late 60's in my 69 DART GTS or 72 Demon 340. Funny how I evolved from 340 cubes to 340 horses (and climbing) over a 36 year period.

Adding the stage II Jetchip shortly thereafter, (after much arm-twisting by Meister) really picked things up. Tranny came to life, reduced shift lag, and moved my shift point up nicely.

The GSM torque modulation & fan mod is still, alas, in it's original box. I can't get the nerve up to attepmt it, since I am horrible with anything electrical and having to do with wires. (My son had to set up my home theatre system as I got lost in the maze of cables, etc.)

Next will be the 180 degree Thermostat, to keep things running cooler. I may wait until after the winter for this, however.


Everything else is basically cosmetic. Tinted windows, wood dash kit (all 179 pieces of it), Ultimate pedals, all kinds of hemi and 300c emblems in the interior; billet headrest spacers and door lock posts, after market Sirius, Custom 300C floor mats,mud flaps

blah blah blah

All to personalize my ride. And that, my friends is what it's all about.

So go out and mod up. Whatever you like is what you should do. Many will opine, but stop you, that should not.

Have fun, and stay tuned for many more helpful tips and tricks from the fine folks on this site.
 

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How are you dealing with the MDS-drone at cruising 60+ mph?
My back seat passengers can't stand it and I've not recieved any help from Magnaflow.
I will say this, MF's better response, better gas milage and they sound great at idle and better on the trottle!
A little help would be appriciated though.
 

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Discussion Starter · #13 · (Edited)
crhemi said:
How are you dealing with the MDS-drone at cruising 60+ mph?
My back seat passengers can't stand it and I've not recieved any help from Magnaflow.
I will say this, MF's better response, better gas milage and they sound great at idle and better on the trottle!
A little help would be appriciated though.
I've since re-torqued all clamps, twice, crhemi, (just as the instructions state, they WILL loosen with driving) and made sure that there were no clearance problems anywhere.

The drone is now essentially unnoticeable except from the back seat at Interstate Highway speed. A member recently posted on one of these lx-related forums that he'd quieted that down by applying sound deadening material on all reachable bare sheet metal in the trunk. He pulled the spare, apparently removed the carpet, etc., then applied Peel-n-seal to all the sheet metal (even under the rear window ledge, from below). He said it helped a lot. I plan on doing the same thing eventually.

But first get your car on a lift & retighten all clamps after verifying that the clamps are fully forward on their tubing. If not, loosen them and reposition them to the end of that tubing section, then really torque them down. Otherwise the tubing sections won't seal properly.

If repositioning/re-torquing the band clamps and adding the sound deadening material to the trunk surfaces don't bring the rear seat sound level down to an acceptable point, contact Richard, specifically, at Magnaflow. He's the design engineer and can tell you how to perform an internal mod to the main muffler that will quieten things a bit.

Good luck. And please share back with us any findings and/or clever fixes you come up with.
 

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Use Dynamat

Meister said:
A member recently posted on one of these lx-related forums that he'd quieted that down by applying sound deadening material on all reachable bare sheet metal in the trunk. He pulled the spare, apparently removed the carpet, etc., then applied something called "peel 'n stick" (or similar) to all the sheet metal (even under the rear window ledge, from below). He said it helped a lot. I plan on doing the same thing eventually.

.
There are two products used in car audio that that member was probably referring to that deaden the sound - called dynamat and fatmat. The hot tip is to warm it up real good with a heat gun first before you cut it to shape..... You can get dynamat at Best Buy in the car audio department.
 

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Discussion Starter · #15 ·
zenhog said:
There are two products used in car audio that that member was probably referring to that deaden the sound - called dynamat and fatmat. The hot tip is to warm it up real good with a heat gun first before you cut it to shape..... You can get dynamat at Best Buy in the car audio department.
Thanks, zenhog.

I found the original reference - the material is called Peel-n-seal, the reference is here: http://www.lxforums.com/board/showthread.php?p=166098#post166098

Anyone with experience with these 3 sound-deadening products care to offer an opion as to which is most effective overall?
 

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Discussion Starter · #16 · (Edited)
Update

Just back from one of life's finer weekends. :wink1:

The tremendous driveability improvement that the Jet Chip provides the LX Hemi is nowhere more apparent than when flogging it in the tight twisties. Motor and transmission were instantly responsive to the demands of repeated quick cycles of WOT to ABS chatter to WOT....

Under those extremely demanding conditions the stock SRT8s I was running with in the mountains above San Diego were at least equalled by the combination of the instant responsiveness of my drivetrain and the superior suspension that the KW/Hotchkis combo provides my sweet C, most notably in the tightest, gnarliest, sections.

In terms of responsiveness, suspension, and overall balanced package there was one clear winner at the end of 45 spirited minutes of WOT flogging - Jet Chip and the KW V2/Hotchkis anti-sway killer suspension combo.
 

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After spending Sunday flogging the SRT-8s at Sears Point...I am very happy with my 5.7 too. No drone with my Zoomers BTW and with the Superchips programmer coming next month I'm chomping at the bit to experience the next level...6250 RPM shifts and no speed limiter!

Great write up Jim, couldn't agree with you more!
 

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Great writeups in this thread. Well authored and very entertaining.

That said, I think there's quite a bit of subjectivity here to which I'd like to offer an alternate viewpoint.

I'm a racer. I rent tracks and flog cars. I've owned 30-something cars in the last 10 years and many of them were high performance. . . some extremely so. This is just some background so that you don't think I'm some doe-eyed noob WRT auto performance.

I owned one of the first 300Cs on the block. Now I own a CSRT-8. Loved the C. . . modded it out as soon as I could with a Jet Chip, intake (AIRAID at the time), and custom exhaust. . . even did a custom X pipe eventually. I flogged that car. . . the Contis were near-bald inside a month. That said, there was NEVER a point in time at which my C was even in the same neighborhood as the SRT-8. If I were driving both at the ragged limits around a decent track. . . say Spokane Raceway. . . I'd see the SRT once at the beginning of the race, lose it through turn 1, and never see it again until it lapped me. I'd have needed to add a blower to the C, do some serious brakes and some suspension to even make it a contest.

So, no cut on the 5.7. . . it's awesome. I just want to give the 6.1 (and the accompanying programming, braking, and suspension) it's due.
 

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Discussion Starter · #20 ·
fathemi said:
...no cut on the 5.7. . . it's awesome. I just want to give the 6.1 (and the accompanying programming, braking, and suspension) it's due.
No one here is unaware of the phenomenal performance bargain the SRT8s are, fathemi.

But even the SRT8s can benefit greatly from mods that remove engine & tranny lag, and improve their handling abilities.

This was clearly demonstrated this past weekend on a number of occasions. :wink1:
 
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