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We recently had a Trackhawk in to perform a series of performance modifications and custom OST Dyno PCM and TCM tuning.

In this test segment we installed a Litens "Hellraiser" 2.72 upper pulley.
We also applied the standard OST Dyno PCM and TCM tuning (also available via email tuning - https://ostdyno.com/tuning-options/remote-tuning-options/remote-tuning-requirements-and-policies/ )

The results were very impressive - look at the gains across the entire RPM range!
Keep in mind that this was on 93 octane. Tuning with race fuel or E85 would have yielded even more impressive gains.

This is a perfect example of why "peak" horsepower numbers can be misleading.
Peak power gains over a stock Trackhawk w/OST custom tuning are not as impressive as the AWHP gains across the entire RPM range - This is what will win races, not peak HP.

Initial testing covered in a previous post involved this same Trackhawk in completely stock form followed by OST Dyno custom PCM tuning.
See those results here: https://www.jeeptrackhawk.org/forum/33-engine-performance-discussion/5546-ost-dyno-trackhawk-tuning-mods-test-results.html

Stay tuned for future posts where we will cover the results of our testing on this same Trackhawk with:
1. OST Level 2 package

We have been selling, installing and tuning our 6.2 Hemi modification packages since 2015 with excellent results. We have also been selling these same packages for Trackhawks to shops and customers since early 2018. https://ostdyno.com/hellcat-performance/

We were fortunate enough to have a customer willing to drop off his Trackhawk for a week so that we could individually test each of our packages in-depth on this platform. We have been remote tuning Trackhawks around the globe for almost a year but have not had this opportunity to take one individual vehicle and apply all of our packages to have an accurate basis for results. This is the same strategy we previously used on our shop Hellcat which has allowed us to develop highly accurate PCM and TCM tuning packages used on 100's of Hellcats and Demons around the world.

Step 1:
Our first test was to establish a baseline for this completely stock Trackhawk.

Step 2:
We then applied the OST Dyno PCM and TCM tuning to the completely stock Trackhawk.

Step 3:
Install a Litens 2.72 Hellraiser pulley, pin the crank, applied OST Dyno PCM and TCM tuning

Added bonus:
With our Mustang AWD dyno we are also able to perform 1/4 mile testing.
In 2wd mode the test results from our dyno for 1/4 mile pulls are generally within .1 - including cars as quick as 8 seconds in the 1/4.
In 4wd mode all the vehicles we have attempted 1/4 mile tests with were too powerful to secure to the dyno for accurate test results (i.e. 1400+ crank HP). The 1/4 mile results are unverified until we test this Trackhawk in the Spring when our local tracks open.

We did use the Performance Pages to record results in our 1/4 mile testing. The ET's displayed were always .2 or more quicker than what the dyno was showing. We have been informed by remote tuning customers that run their Trackhawks at the drag strip that the Performance Pages results are generally within .05-.1 but have not verified this personally.

Our test results are as follows: (dyno graphs below)
1. Stock
- All Wheel HP = 553
- 1/4 mile ET on the dyno = 11.85
- 1/4 mile ET on Performance Pages = 11.6

2. Stock w/OST Dyno PCM and TCM Tuning
- All Wheel HP = 622 (60+ AWHP gain)
- 1/4 mile ET on the dyno = 11.6
- 1/4 mile ET on Performance Pages = 11.4

3. Hellraiser 2.72 w/OST Dyno PCM and TCM Tuning (dyno graphs below)
- All Wheel HP = 664 (look at the gains across the board!)
- 1/4 mile ET on the dyno = 11.0
- 1/4 mile ET on Performance Pages = 10.7


Test Subject:




Dyno graphs comparing Stock vs. Stock w/OST Tuning vs. Hellraiser pulley w/OST Tuning

 

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:surprise: Wow!! Stock injectors, and just a 2.72" upper (I assume a new, properly sized belt as well) and you picked up that?! On 93?!

Great gains, Mike.

Quick ?: Why is pinning the crank necessary when you're keeping the stock lower pulley/balancer assembly? I'm new to the HC engine family, so I just don't know. Thx.
 

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Discussion Starter #3
:surprise: Wow!! Stock injectors, and just a 2.72" upper (I assume a new, properly sized belt as well) and you picked up that?! On 93?!

Great gains, Mike.

Quick ?: Why is pinning the crank necessary when you're keeping the stock lower pulley/balancer assembly? I'm new to the HC engine family, so I just don't know. Thx.
Thanks and yes, it is impressive.

We have seen numerous completely stock Hellcat lower pulleys that showed signs of spinning when we removed them to replace with an ATI lower. So even if a customer only wants to install an upper pulley (Metco or Hellraiser) we insist on pinning the crank. Here is a thread my son Micah started on this exact issue. The thread went sideways after a few pages but if you read his first post in the thread you will understand why we take this stance:
https://www.hellcat.org/threads/another-if-you-dont-pin-it-youll-spin-it-thread.222433/
 

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I'll be pinning my crank when the ATI lower goes on in a few weeks. Cannot wait to see what Mike can do with it once we get some boost to play with!
 

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Discussion Starter #6
Mike, what is stage 2 over the 2.72? Injectors, thermostat and more HP (timing)?
Our Level 2 Package includes an ATI 10% overdrive lower pulley, a Metco upper pulley system with the choice of a 2.65, 2.75 or 2.85 pulley, appropriate belt, ID1050x injectors, a 180 thermostat and definitely not more timing :)

The results for this combo, which is our biggest seller, is even more impressive. Stay tuned for our post on that upgrade.

On this particular Trackhawk we used the 2.85 upper and tuned it for 93 octane and will provide a race fuel tune as well when we take it to the track in the Spring.
 

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Our Level 2 Package includes an ATI 10% overdrive lower pulley, a Metco upper pulley system with the choice of a 2.65, 2.75 or 2.85 pulley, appropriate belt, ID1050x injectors, a 180 thermostat and definitely not more timing :)

The results for this combo, which is our biggest seller, is even more impressive. Stay tuned for our post on that upgrade.

On this particular Trackhawk we used the 2.85 upper and tuned it for 93 octane and will provide a race fuel tune as well when we take it to the track in the Spring.
Got it. I thought you were using the 2.72" as the basis for your Level 2 in this build. Watching these results with GREAT interest!
 

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Are there any advantages between using an ATI or an Innovators West lower pulley? Or is it just personal brand preference? Aside from that, I know that pinning the crank is a must with any mod.

Thanks!
 

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Discussion Starter #9
Are there any advantages between using an ATI or an Innovators West lower pulley? Or is it just personal brand preference? Aside from that, I know that pinning the crank is a must with any mod.

Thanks!
Overkill, we are ATI dealers and prefer the 10% overdrive vs. the IW which I believe is less than 10%. The IW is a nice unit and many of the shops that we remote tune for prefer this over the ATI. So to answer your question - personal preference and the fact that we buy the ATI's by the dozen.
 

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Overkill, we are ATI dealers and prefer the 10% overdrive vs. the IW which I believe is less than 10%. The IW is a nice unit and many of the shops that we remote tune for prefer this over the ATI. So to answer your question - personal preference and the fact that we buy the ATI's by the dozen.
Thanks Mike! That is good to know on the dampers.

Do you do a lot of E85 conversions on the hellcats?
I have been doing some homework on the pros and cons and there are a lot of mixed reviews. The highest octane available in my area is 91, but there 3 gas stations that carry E85 within 5 miles radius of where I live.

I think we all know the positives with running E85, but here are some of the cons that I have learned so far.
There may be issues with cold starts or sometimes even hot starts, and I like to use the remote start on cold days.
Have to change the oil more often ~ 2,500-3,000 miles (Someone on the hellcat forum said it can eat thru piston rings over time, is that true?)
Will burn thru fuel ~30% faster so more frequency in fill ups, but in my area it is cheaper than regular unleaded.

Besides having to upgrade the injectors, will the rest of the stock fuel system (fuel pump) handle the demands of running E85? I read there is no fuel filter on the HC’s and TH’s, not sure if that is true.

I am just trying to learn as much as possible, and keep my DD dependable.
Thank you for your time.
 

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Discussion Starter #11
Thanks Mike! That is good to know on the dampers.

Do you do a lot of E85 conversions on the hellcats?
I have been doing some homework on the pros and cons and there are a lot of mixed reviews. The highest octane available in my area is 91, but there 3 gas stations that carry E85 within 5 miles radius of where I live.

I think we all know the positives with running E85, but here are some of the cons that I have learned so far.
There may be issues with cold starts or sometimes even hot starts, and I like to use the remote start on cold days.
Have to change the oil more often ~ 2,500-3,000 miles (Someone on the hellcat forum said it can eat thru piston rings over time, is that true?)
Will burn thru fuel ~30% faster so more frequency in fill ups, but in my area it is cheaper than regular unleaded.

Besides having to upgrade the injectors, will the rest of the stock fuel system (fuel pump) handle the demands of running E85? I read there is no fuel filter on the HC’s and TH’s, not sure if that is true.

I am just trying to learn as much as possible, and keep my DD dependable.
Thank you for your time.
We do have Hellcats, Demon's and one Trackhawk running ethanol.
There may be cold start issues in very cold conditions.
I have not heard of or experienced ethanol eating through piston rings.
You will use significantly more ethanol then gasoline - hence the need for the larger injectors.
You can run E85 with the stock Trackhawk and Demon fuel systems using larger injectors on a stock or mildly modified vehicle.
 

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We do have Hellcats, Demon's and one Trackhawk running ethanol.
There may be cold start issues in very cold conditions.
I have not heard of or experienced ethanol eating through piston rings.
You will use significantly more ethanol then gasoline - hence the need for the larger injectors.
You can run E85 with the stock Trackhawk and Demon fuel systems using larger injectors on a stock or mildly modified vehicle.
Ok. I still have not been scared off of the thought of running E85 yet…
Thank you for your insight and time.
 

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Pardon me saying this as it in no way is an attempt to take away from your work/results as they are incredible, but why even do a lower pulley?!?! What you neglected to mention, that is almost more important than HP gains on a large vehicle are the amazing TRQ gains!!! If I read the dyno correctly after having a few beverages, you gained over 100 WTRQ. The reason to get an OD pulley (at least several years ago) was to help increase torque more so than HP, and by God you don't seem to have any issues with TRQ! When I added and OD pulley in the past, the results over the long term proved unfavorable as the constant over spinning of the blower created an inversely linear power depreciation from heat soak. I'm not saying that's the case with these trucks, but ****, I should think an upper only would be enough to satiate 99/100 of your customers :) Am I way off base here?? GREAT WORK!
 

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Discussion Starter #14
Pardon me saying this as it in no way is an attempt to take away from your work/results as they are incredible, but why even do a lower pulley?!?! What you neglected to mention, that is almost more important than HP gains on a large vehicle are the amazing TRQ gains!!! If I read the dyno correctly after having a few beverages, you gained over 100 WTRQ. The reason to get an OD pulley (at least several years ago) was to help increase torque more so than HP, and by God you don't seem to have any issues with TRQ! When I added and OD pulley in the past, the results over the long term proved unfavorable as the constant over spinning of the blower created an inversely linear power depreciation from heat soak. I'm not saying that's the case with these trucks, but ****, I should think an upper only would be enough to satiate 99/100 of your customers :) Am I way off base here?? GREAT WORK!
I am surprised that nobody picked up on the torque increase sooner. These days it seems that most folks are concerned about peak HP. For us the main focus is ET or MPH which really tells the entire story of any modifications.

Concerning the addition of a lower pulley - please keep in mind that these engines and superchargers are identical to what has been in the Hellcat's since 2015. For over three years we have been modifying, testing and tuning this engine/supercharger combination with excellent results. Without a doubt the 10% overdrive lower and the properly sized upper pulley for the fuel type being run will make the most horsepower and torque as well as produce the quickest ET and highest MPH.

Concerning the heat produced by the SC - If anyone is spinning their engine at 4000+ RPM constantly then I would not recommend even changing the upper pulley since heat will become an issue. However, for the weekend racer or someone trying to extract the most power out of this platform a properly sized upper and lower pulley is hard to beat. There are 100's of Hellcats out there with the stock blower, 10% lower and a smaller upper that are driven daily during good weather with no issues. Then again there are completely stock Hellcats with stock pulleys that have had blower bearing failures.
My personal Hellcat has a 10% lower and 2.65 upper, is raced every weekend during the summer since 2015 and still has the factory SC. I shift it at 7-7100 RPM when racing. It is impressive that this combo just keeps on going.

Wait until you see what this Trackhawk did with our "Level 2" package. Absolutely impressive!
 

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Thanks Mike! That is good to know on the dampers.

Do you do a lot of E85 conversions on the hellcats?
I have been doing some homework on the pros and cons and there are a lot of mixed reviews. The highest octane available in my area is 91, but there 3 gas stations that carry E85 within 5 miles radius of where I live.

I think we all know the positives with running E85, but here are some of the cons that I have learned so far.
There may be issues with cold starts or sometimes even hot starts, and I like to use the remote start on cold days.
Have to change the oil more often ~ 2,500-3,000 miles (Someone on the hellcat forum said it can eat thru piston rings over time, is that true?)
Will burn thru fuel ~30% faster so more frequency in fill ups, but in my area it is cheaper than regular unleaded.

Besides having to upgrade the injectors, will the rest of the stock fuel system (fuel pump) handle the demands of running E85? I read there is no fuel filter on the HC’s and TH’s, not sure if that is true.

I am just trying to learn as much as possible, and keep my DD dependable.
Thank you for your time.
Run E50 (mix of 91 and E85) for daily driving.
 
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