{"id":27603,"date":"2019-08-27T05:00:50","date_gmt":"2019-08-27T09:00:50","guid":{"rendered":"http:\/\/www.dodgegarage.com\/news-api\/?p=27603"},"modified":"2024-03-25T11:24:17","modified_gmt":"2024-03-25T15:24:17","slug":"when-you-cant-leave-well-enough-alone","status":"publish","type":"post","link":"https:\/\/test.api.dodgegarage.com\/news\/how-to\/2019\/08\/when-you-cant-leave-well-enough-alone.html","title":{"rendered":"When You Can’t Leave Well Enough Alone"},"content":{"rendered":"\n

I don\u2019t think many people would argue that Dodge and the\nmaniacs at SRT\u00ae<\/sup> hit a home run with the Dodge Challenger SRT Demon, which then\ncarried over to the Dodge Challenger SRT Hellcat Redeye. Coming off the\nassembly line, the SRT Hellcat Redeye packs 797 horsepower at the crank. That is pretty\nimpressive. But you have to ask yourself, \u201cWhat kind of person buys a car with\n797 hp?\u201d<\/p>\n\n\n\n

The correct answer is \u201cA person who wants over 1,000 hp.\u201d <\/p>\n\n\n\n

Note: If you like your warranty, don\u2019t continue reading.<\/strong><\/p>\n\n\n\n

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My shop recently had a brand-new Plum Crazy Purple Widebody\nSRT Hellcat Redeye dropped off to us with one request: \u201cMake it stupid fast.\u201d <\/p>\n\n\n\n

It doesn\u2019t take much to make the SRT Hellcat Redeye really scream. Oftentimes, the restrictions put on the OEM for how a car can perform in stock form\ncome from things like emission regulations, liability, reliability, legal and\nperforming in any environment that we – the end user – will put it in. When 797\nhorsepower just isn\u2019t enough, it\u2019s time to dig in and just get silly. There is one thing to clarify before we get\nstarted just in case you may be confused: There are two ways to measure\nhorsepower. <\/p>\n\n\n\n

The first is on an engine dyno. This measures the horsepower\nof the engine as a standalone unit. This is how Dodge – and every other automaker –\nmeasures the power of their engines. It does not take into account things like\nthe power loss through the rest of the drivetrain through the torque converter,\nthe transmission, the rear differential and weight\/mass of the tires.<\/p>\n\n\n\n

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The second way to measure horsepower is with a chassis dyno.\nThis is generally how the aftermarket measures and tests cars. It measures how\nmuch power is applied at the wheels after any power loss from the other\ncomponents in the drivetrain. That being said, the SRT Hellcat Redeye makes 797 stock\nhorsepower at the crank, but at the rear wheels, it makes somewhere between\n650 and 700 horsepower, depending on the dyno and conditions. The key to dyno numbers is not\nto get tied up in the before and after numbers. The focus should be on the\ndifference or net gain between the two. Too many factors affect the actual\nreading itself. <\/p>\n\n\n\n

The goal for this SRT Hellcat Redeye was to be 100% streetcar first and\nforemost. We aren\u2019t building a racecar here. The second goal is to run high 8-second to low 9-second quarter-mile times with a tire change. One of the main\nlimiting factors on where you can go with the supercharged 6.2L HEMI\u00ae<\/sup> engine is what\ntype of fuel you are willing to run versus how much boost you can run. The\nquickest way to more power on this platform is more boost from the\nsupercharger. Due to a whole host of reasons that we won\u2019t discuss here, there\nare limits on how much boost you can or should run on your standard pump gas.\nIf you want to crank up the boost, you have to run a better fuel. High-octane\nrace gas has been the go-to for years for streetcars. There are some pros to\nrunning race gas; however, it\u2019s very expensive, ranging from $8 to $12 a gallon.\nThat wipes out the main goal of keeping this project a streetcar. The more\nreasonable and modern go-to for many boost addicts these days is E85 FlexFuel.\nE85 is 85% ethanol, and has all the right goodies in it to run boost for days.\nThe best part about E85 is that its dirt cheap, usually ranging from $1.80 to $2.20\na gallon; cheaper than standard 87 octane. But running E85 will cover 95% of\nany power need you have on a streetcar. With the owner of the SRT Hellcat Redeye being on\nboard for running E85, hitting our two main goals would be easy. <\/p>\n\n\n\n

There are many ways to skin a (hell)cat. We needed more\nboost. We could have opted for an aftermarket supercharger, but those cost\nanywhere from $6,000 to $9,000. Instead, we decided to use the stock supercharger,\nmodify and crank more boost out of it. Creating more boost out of the stock\nsupercharger is simple, as it\u2019s just math and some basic physics: spin the\nrotors faster. <\/p>\n\n\n\n

There are three ways to do this. You can add a smaller drive\npulley on the supercharger, add a larger harmonic balancer on the crankshaft\nor, if you are wild, do both. We did both.<\/p>\n\n\n\n

We opted for a Litens Hellraiser 2.72\u201d decoupling pulley that functions the same as the stock Litens Hellraiser pulley, but makes more power. We also added an ATI 10% overdrive harmonic dampener to spin that little 2.7L blower even more. In stock form, the supercharger cranked out roughly 14 psi of boost. After spinning it faster, we were able to produce roughly 22.5 psi of boost. That is a hefty increase. <\/p>\n\n\n\n

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Keeping engine temps down is another cheap and easy way to\nmaximize those ponies. The easiest way to do this is with a simple coolant\nthermostat swap. Since the 5.7 HEMI engine came out over 15 years ago, mod addicts\nhave been swapping out the stock thermostat that runs at roughly 210 degrees\nfor a 180-degree thermostat. This drops engine coolant temps 30 degrees and\nhelps the motor run cooler, maximizing power. We opted for a Mishimoto\n180-degree thermostat. Along with some fan adjustments in the PCM calibration,\nit can work wonders. <\/p>\n\n\n\n

Since we opted to run E85, we needed to make some upgrades to\nthe fuel system. These are relatively easy on the SRT Demon and SRT Hellcat Redeye. E85 uses\nabout 30% more fuel than 93 octane. This means we need to be able to flow much\nmore fuel. Luckily, the SRT Hellcat Redeye comes equipped with dual fuel pumps right off the\nassembly line. They are capable of pumping incredible amounts of fuel. We just\nneeded to add a little help to them by increasing the voltage to those pumps to\nmake them spin just a little faster. A Kenne Bell \u201cBoost A Pump\u201d was used to\nachieve this. It\u2019s a simple module that increases voltage to the fuel pumps when\nboost is sensed. It\u2019s extremely simple and basic, and compared to replacing the\nfuel pumps and basket assembly, much faster and cheaper. <\/p>\n\n\n\n

To go along with the increased fuel needs, we needed to\nupgrade the fuel injectors. There is some science involved when sizing\ninjectors. Simple factors like elevation and temperature come into play with\nmaking sure you have a large enough fuel injector for the system. To make sure\nwe had enough to cover the car’s fuel needs at any ambient temperature and\nelevation, and to run E90 when we really want to push it, we chose Injector\nDynamics 1700X fuel injectors that are sized at a whopping 1,700cc and built\nwith internals that won’t be damaged by high ethanol content fuel. <\/p>\n\n\n\n

With the engine pushing so much more air and power through\nit, we needed to help all that goodness make its way out of the tailpipe. While\nwe have done plenty of these builds using the stock exhaust system, this SRT Hellcat Redeye\nowner wanted a little something extra. A set of Hooker long tube headers and\nconnecting pipes were mated up to a Hooker cat-back exhaust system. The combo\nwould ensure we are flowing all the exhaust out of the back of the car as\nefficiently and less restrictive as possible. And if you hate your next-door\nneighbor, it has the perfect sound to make sure they know. <\/p>\n\n\n\n

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Another important modification was made to the car for the\nmain purpose of helping it on the track. Heat rises. All those ponies stirring\naround the engine bay make for a lot of heat. After a run at the drag strip, the\ncar sits basking in the sun with all that heat raising up front the engine\nacross the top end of the motor and supercharger heat soaking the intake tract.\nIt takes a considerable amount of time to drop the physical temperature of the\nsupercharger back down to a level where ideal intake air temps are achievable. An\naluminum supercharger sitting on top of aluminum heads with scalding hot\nheaders mounted to them simply turns the supercharger into a giant heat sink.\nWe sourced a set of FI Interchillers supercharger spacer plates and heat blanket\nin an effort to help prevent this. The spacers help prevent heat transfer from\nthe heads to the supercharger, which lowers heat soak and drastically cuts down\ncool-down time. The insulation blanket helps reject heat from the top of the\nmotor. The result is lower and fast intake air temperatures that directly\nrelate to miles per hour at the strip. Simple and effective. <\/p>\n\n\n\n

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Finally, none of these parts will work at all without a good\ncalibration. That can often be the most challenging part. Always seek the\nexpertise of an experienced tuner when modifying your car. One small error\ncould cause catastrophic results. <\/p>\n\n\n\n

Each year, tuning logic changes on these cars and there is\nusually a learning curve with each new model year. The SRT Hellcat Redeye was no different.\nInitially, we assumed it would be the same calibration as the SRT Demon; however,\nthat turned out to not be the case at all. We won\u2019t go into the details of\ntuning other than to let you know why it’s needed. <\/p>\n\n\n\n

After tossing this many parts on the car, changing fuel\ntype, boost levels, power levels and overall performance of the car, you have\nto program the computer to function and command properly with the new\ncomponents. Just like throwing a new carb on an old 426 HEMI engine and having to tune\nthe carb, turning a few screws to get the perfect blend of air and fuel. It\u2019s\nJUST like that. Actually, no it isn\u2019t, really. It\u2019s like being a rocket\nscientist, mechanic and software developer all in one. There are thousands\nupon thousands of settings and codes driving that fire-breathing monster. Every\nsetting in there has to be in perfect harmony with each other. If they aren\u2019t,\nbest case is the car won\u2019t run, and the worst case is \u201ckabooooom!\u201d Needless to\nsay, the car was finished up with a conservative tune to utilize all the new\nparts, running on pump E85 and a ripping transmission tune. <\/p>\n\n\n\n

The end results?<\/p>\n\n\n\n

On the particular day that we made a baseline pull on our chassis dyno, the 2019 SRT Hellcat Redeye cranked out 663 horsepower and 637 torque to the rear wheels. The numbers seemed a bit soft, but considering it being close to 90 degrees and high humidity, it could be close. But again, we don\u2019t care so much about the starting numbers or the ending numbers themselves. We are interested in the increase between the two. After all parts were installed and the tune honed in, this purple monster ripped out 905 horsepower and 967 torque at the rear wheels on an equally hot and humid day on the same dyno. That\u2019s an increase of 242 horsepower and 330 lb.-ft. of torque at the wheels with a few small bolt-on parts. The car still maintains 100% street drivability, comfort and features, and it even runs on fuel cheaper than 87 octane. It can be driven to the track with air conditioning, comfy leather seats and a ripping 18-speaker audio system, and tear down the track at 150 mph and low 9-second elapsed times. <\/p>\n\n\n\n

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Is it overkill? You better believe it! <\/p>\n","protected":false},"excerpt":{"rendered":"

I don\u2019t think many people would argue that Dodge and the maniacs at SRT\u00ae hit a home run with the Dodge Challenger SRT Demon, which then carried over to the Dodge Challenger SRT Hellcat Redeye. Coming off the assembly line, the SRT Hellcat Redeye packs 797 horsepower at the crank. That is pretty impressive. But you have to ask yourself, \u201cWhat kind of person buys a car with 797 hp?\u201d The correct answer is \u201cA person who wants over 1,000 hp.\u201d Note: If you like your warranty, don\u2019t continue reading. […]<\/p>\n","protected":false},"author":38,"featured_media":27645,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[639],"tags":[526,2227],"class_list":["post-27603","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-how-to","tag-challenger","tag-mods"],"acf":[],"custom_fields":{"post_thumbnail_image":"https:\/\/test.api.dodgegarage.com\/news\/wp-content\/uploads\/2019\/08\/feature-32.jpg","icon_selection":"article","external_link":"","featured_article":[],"upload_background_image":""},"_links":{"self":[{"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/posts\/27603"}],"collection":[{"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/users\/38"}],"replies":[{"embeddable":true,"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/comments?post=27603"}],"version-history":[{"count":11,"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/posts\/27603\/revisions"}],"predecessor-version":[{"id":27777,"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/posts\/27603\/revisions\/27777"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/media\/27645"}],"wp:attachment":[{"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/media?parent=27603"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/categories?post=27603"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/test.api.dodgegarage.com\/news\/wp-json\/wp\/v2\/tags?post=27603"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}