Some questions about my Arrington Motor........

[charginscott]

if they are pulling that kind of timing what are they seeing? Or not seeing and guessing?

are they using a good wideband and watching for knock or are they just guessing?

[Tim@Arrington]

One of my last handoffs from old Virginia Arrington to new Michigan Arrington (Diversified Creations) is this forum. I will point out this thread -- they might have ideas to help. They don't do email tunes anymore, though.

Carb Connection has been a reliable dealer for Arrington for a long time. This wasn't their first Arrington engine rodeo, although often they used Arrington tunes. I would guess that they simply wanted to play it safe. You are ~70 HP over stock for the 6.1 engine. But if you find someone who can safely tune it more aggressively (or talk CarbConn into it), you would certainly get more with the long tube headers.

As for block upgrades -- if I was taking your call a year ago, here is what I would have offered (and Arrington today will probably offer -- sales@shophemi.com).

Arrington has years of success taking the 6.1 block up to 440 c.i. This configuration is usually built high-compression and Arrington refused to put boost on it -- the walls get too thin. The most popular, though, is the forged 426 c.i. (7-liter) built with low compression (9:1) and set up for boost. I personally own one of these in my Challenger. Your block could be rebuilt to this spec. I don't think just changing the head gaskets is a great plan -- but it certainly would lower the compression. In any event mild boost (8 psi) won't hurt it just as is.

BTW, rebuilding it to a 426 is pretty similar to buying a new 6.4-based 426 stroker or just getting a Hellcat block. Do you have any other use for the 6.1-based 392? Shame to tear it down if it doesn't have many miles.

In summary -- should be more room in the tune (if done carefully), 8 psi supercharger boosting is fine (need a new tune, though), can rebuild the block bigger, don't bother with changing head gaskets.

[BigMurph]

One of my last handoffs from old Virginia Arrington to new Michigan Arrington (Diversified Creations) is this forum. I will point out this thread -- they might have ideas to help. They don't do email tunes anymore, though.

Carb Connection has been a reliable dealer for Arrington for a long time. This wasn't their first Arrington engine rodeo, although often they used Arrington tunes. I would guess that they simply wanted to play it safe. You are ~70 HP over stock for the 6.1 engine. But if you find someone who can safely tune it more aggressively (or talk CarbConn into it), you would certainly get more with the long tube headers.

As for block upgrades -- if I was taking your call a year ago, here is what I would have offered (and Arrington today will probably offer -- sales@shophemi.com).

Arrington has years of success taking the 6.1 block up to 440 c.i. This configuration is usually built high-compression and Arrington refused to put boost on it -- the walls get too thin. The most popular, though, is the forged 426 c.i. (7-liter) built with low compression (9:1) and set up for boost. I personally own one of these in my Challenger. Your block could be rebuilt to this spec. I don't think just changing the head gaskets is a great plan -- but it certainly would lower the compression. In any event mild boost (8 psi) won't hurt it just as is.

BTW, rebuilding it to a 426 is pretty similar to buying a new 6.4-based 426 stroker or just getting a Hellcat block. Do you have any other use for the 6.1-based 392? Shame to tear it down if it doesn't have many miles.

In summary -- should be more room in the tune (if done carefully), 8 psi supercharger boosting is fine (need a new tune, though), can rebuild the block bigger, don't bother with changing head gaskets.

Thanks for the reply, I appreciate it.

So the motor is not a factory 6.1L, its actually a 6.1L based 6.4 long block "fully forged option" from Arrington. I have all the accompanying paperwork from Arrington as far as the build sheet, and dyno sheet and photos of the build.

At Arrington with factory exhaust and cat's it made 555hp at 6200rpm and 532ft/lb of tq at 5100rpm all at the crank. Since then some changes have been made as far as MSD ignition system, different air intake etc, as well as solidworks LT's with the "off road" piping as they so call it. With the addition of all this, in a 2007 charger, factory transmission and rearend, with 20inch hellcat rims and MT Street Comp 275/40s, 91 degree weather (inside the shop) at 150ft above sealevel. it made 422.93hp and 398.89tq on a dynojet using HP Tunes.

that's a loss of 23.8% hp and 25.19 tq.

The third time I had it tuned by them the owner said he contacted his "engine guy" about the timing and his guy said "all the motors we send your way are 11:1 compression, you shouldn't have to pull that much timing out. Either your tune is **** or your guy doesn't know what hes doing (the tuner).

So that's where im at gents.

[DBL.DWN]

Ild be curious to see the build sheet and dyno sheet.

Im wondering if Arringtons numbers were on a engine stand or in a chassis.

[BigMurph]

Ild be curious to see the build sheet and dyno sheet.

Im wondering if Arringtons numbers were on a engine stand or in a chassis.

I thought I mentioned this, but yes these are on an engine dyno. Correct me if I’m wrong but I’m not sure how you would measure crank hp from a chassis dyno. Anyway if I could actually get something to upload I would but I think I’m too new

[DBL.DWN]

I thought I mentioned this, but yes these are on an engine dyno. Correct me if I’m wrong but I’m not sure how you would measure crank hp from a chassis dyno. Anyway if I could actually get something to upload I would but I think I’m too new

Exactly. You are comparing engine dyno numbers to chassis dyno numbers.

oops I see now in that latest post you said "at the crank".

[BigMurph]

Exactly. You are comparing engine dyno numbers to chassis dyno numbers.

oops I see now in that latest post you said "at the crank".

Im only comparing because on average there is a 17% power loss through the drivetrain

[DBL.DWN]

Im only comparing because on average there is a 17% power loss through the drivetrain

Theres way too many differences going on to be comparing like this. I wouldnt be worried about the numbers.
Just make sure the motor is happy. Run a compression test, leak down test if needed. Check the plugs. Sounds like the tune needs some major help.

[BigMurph]

I understand why this may not seem like a big deal to anyone other than me, because this is not your car. The original owner threw a rod so he was left with no other choice than to purchase a new engine. So lets look at the facts:

1. Stock 6.1L on average puts down 363.5 RWHP in a unmodified 2007 dodge charger srt8. (this is with multiple reports from lows of 350 and highs of 380 rwhp so I just found the average)
2. A reman 6.1L hemi will cost $5,000 on average.
3. A P1SC procharger will run $5500
4. Installed at the house free
5. Dyno tune $600
6. Now you're at or over 500 RWHP at about $12000 (were purely talking dollars and HP so that is $12,000 dollars for an increase of aprox 140hp not bad!!

Here is why I am asking all the questions

1. This motor that I have without installation, cost $14,748.02
2. Again a factory 6.1L makes on average 363.5 RWHP
3. My car made 401.9 RWHP
4. $14,748.02 for 38.4 horse power

This is why I am trying to get to the bottom of this. Thats all. Either This guy who originally bought the motor got hosed, or the motor is soft as hell, or I got screwed on close to 1k worth of dyno tunes. Because I refuse to believe that Arrington sold this guy a dud. I refuse to believe that this motor is soft, because it pulls hard as hell, doesn't knock or tick, blows no smoke, burns just the right amount of hemi oil and makes smooth power across the rpms.

So if anyone can point me in the direction of a tuner who wont destroy my bank account and can promise more than 38 horsepower over stock in the pacific north west it would be much appreciated.

[BM_SRT]

Install a wideband afr setup, hook it up inline with your tuner and take some good datalogs with the integrated afr signal.

Send them to Johan / Diablotoona to take a look. He also works with HP Tuners.

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[ChuckWagon]

Have you run the car in the quarter mile to see how performance is? Dyno's can give erroneous numbers and acceleration is really the proof of what kind of power is being made. I dynoed at 450hp/460tq to the rear wheels on a Mustang dyno on 93 octane pump gas. I know from past runs on that dyno on another vehicle that the driveline loss is 25% on my car and the other one (wife's 06 police R/T). So I'm about 600hp/610tq at the crank on pump gas. Running the 1/4 mile on pump gas is fun but when I put in some MS109 I see a major increase in performance and as much as almost 4 tenths quicker ET's. I know I'm making more power on race gas, I just don't know how much more.

But...dynos are for tuning and the real test is how the vehicle accelerate. Maybe do some runs and log as much data as you can and I'm sure someone one here can at least look at the data and advise if they see anything that doesn't look right.

[BigMurph]

----- update------

@ChuckWagon I will be running the car in a week when the track has a test and tune. Lately there have been some big events like the NW Nationals and some reserved track time that has taken away test and tune

According to the tuner

My timing curve starts at 2,000 rpm at 14 degrees advanced and has a smooth curve to 20 degrees at 6400 rpm
AFR is at 15%

So those are my numbers according to the tuner.

[DBL.DWN]

Get it scaled when you go to the track.
And if your at 15:1 afr at wot, then there’s some power loss.


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[ChuckWagon]

I think anything leaner than 13 AFR is asking for trouble at WOT. I run 12 - 12.8 AFR at WOT.

Good luck and have fun! Take it easy the first couple runs out and pay attention to your AFR and oil pressure. If all looks good, make some passes and Datalog your runs.