HPTune

[Sniper]

Will the HPTune be able to do the same thing as a Prefix PCM?

Revised fuel, spark and cam position tables that maximize power increases associated with engine modifications and/or exhaust systems
-Aggressive off-throttle exhaust note
-Requires min 93 octane fuel.
-Rev limit increased to 6600 rpm with decreased hysteresis.
-Allows racing approved final drive ratios from 3.07:1 to 4.10:1.
-First to fourth gear skip shift eliminated for racing use.
-Catalyst monitor disabled to allow the use of high flow / or no catalyst and headers
-Air flow rationality diagnostic disabled which permits greater range of flow modifications
-Misfire detection disabled to permit reduce mass rotating assemblies and further modifications

[Mikey]

Will the HPTune be able to do the same thing as a Prefix PCM?

Revised fuel, spark and cam position tables that maximize power increases associated with engine modifications and/or exhaust systems
-Aggressive off-throttle exhaust note
-Requires min 93 octane fuel.
-Rev limit increased to 6600 rpm with decreased hysteresis.
-Allows racing approved final drive ratios from 3.07:1 to 4.10:1.
-First to fourth gear skip shift eliminated for racing use.
-Catalyst monitor disabled to allow the use of high flow / or no catalyst and headers
-Air flow rationality diagnostic disabled which permits greater range of flow modifications
-Misfire detection disabled to permit reduce mass rotating assemblies and further modifications

Yes and you'll make more power than an arrow pcm

[Sniper]

Thanks! That’s nice to know!
I’m so hoping to get to at least 650rwhp with the heads cam setup.

[Steve M]

If you are going through a tuner, ask him/her that question.

If you are wanting to tune it yourself, I'll issue this warning: HPTuners has changed, and not for the better. I can only assume the EPA got to them, as they have greatly restricted the end-user's ability to modify anything related to emissions equipment.

That may or may not be a big deal to some, but to me, it would be a deal breaker.

What I don't know is if they've implemented the same restrictions on professional aftermarket tuners.

[Sniper]

Steve what specifically would HPTuners not be able to do now emissions wise that would be a deal breaker?

[Steve M]

Personal example: I run high flow cats.

Those cats throw an inefficiency code.

With HPTuners the way it is now, that code would not be able to be turned off.

I hate idiot lights on the dash. I know the cats are inefficient - that's why I bought them. They clean the exhaust up well enough that I don't ever smell it, but the computer (and the Feds I guess) thinks otherwise.

It's more of an annoyance than anything for me, but again, I don't know what else you can and can't do these days, and HPTuners isn't exactly forthcoming about it. For instance, adding a fixed cam to replace the OEM one. Seems like that might trigger a few check engine lights too.

Again, things for a professional tuner might be different, but you're still giving up the ability to do anything yourself with the software, which was 99% of the draw to it.

My $0.00.

[Sniper]

Gotcha! I’ll ask the shop what they will and will not be able to do.

[Jack B]

I am not sure HPT could ever modify the drive ratio error created by a gear change. A 3.73 might not create any issue, whereas, the 4 11 probably would. Prefix can fix that issue with a custom pcm flash.

[Sniper]

So, basically if anyone wants to modify their Viper in any way, the only option now is Prefix PCM and their heads/cam package?

[Steve M]

I am not sure HPT could ever modify the drive ratio error created by a gear change. A 3.73 might not create any issue, whereas, the 4 11 probably would. Prefix can fix that issue with a custom pcm flash.

Can't speak for the Gen 5 crowd, but this functionality exists for the Gen 4.

You have to dig for it, but the table is there.

I've had to modify mine for each gear swap I've done - both 3.55s and 3.73s.

[Steve M]

So, basically if anyone wants to modify their Viper in any way, the only option now is Prefix PCM and their heads/cam package?

If you want to run the stock PCM, it is probably your best bet at this point, especially since they'd have the source code.

But you could always run a different engine management system; you'd just have to open your wallet up a bit more. And it would certainly give you way more flexibility depending on the skill of the installer/tuner. Calvo and Nth Moto would be the ones to talk to about that.

[FrgMstr]

Calvo and Nth Moto would be the ones to talk to about that.

Not speaking for Calvo, but I do believe Antonio told me that my car was the Gen IV heads and cam car he was going to do with HPTuners. My car was delivered on June 18, 2021. I would certainly call to make sure however.

[Mikey]

Personal example: I run high flow cats.

Those cats throw an inefficiency code.

With HPTuners the way it is now, that code would not be able to be turned off.

I hate idiot lights on the dash. I know the cats are inefficient - that's why I bought them. They clean the exhaust up well enough that I don't ever smell it, but the computer (and the Feds I guess) thinks otherwise.

It's more of an annoyance than anything for me, but again, I don't know what else you can and can't do these days, and HPTuners isn't exactly forthcoming about it. For instance, adding a fixed cam to replace the OEM one. Seems like that might trigger a few check engine lights too.

Again, things for a professional tuner might be different, but you're still giving up the ability to do anything yourself with the software, which was 99% of the draw to it.

My $0.00.

My Tuner said that wouldn't be a problem, but I guess I'll find out once I get my motor back

@Sniper 650whp is a given, you could squeeze out a fee more horses with a proper tune

[Sniper]

Torrie will be the tuner

[Mikey]

Torrie will be the tuner

Torrie will NOT touch anything emissions related.

[Sniper]

But the shop can alter the emissions stuff with hptuners, correct?

Are you using something different than hptuners for your build?

[Mikey]

But the shop can alter the emissions stuff with hptuners, correct?

Are you using something different than hptuners for your build?

The shop can. I assume you're renting the dyno and having Torrie tune? I'd clear that up with the shop first before you spend the money.

[Sniper]

Ok, just got off the phone with the shop and I either misunderstood or got my stories messed up with something I red on the forum but the shop already has the software and they are tuning the car themselves, nothing to do with Torrie.

What software for tune are you using?

[Mikey]

Ok, just got off the phone with the shop and I either misunderstood or got my stories messed up with something I red on the forum but the shop already has the software and they are tuning the car themselves, nothing to do with Torrie.

What software for tune are you using?

I got mine sent in remotely from Torrie. It's 20 credits ($1,000) to unlock the ECU, it may be worth purchasing your own dongle in case you need it retuned

[Lawineer]

Are you guys sure it can't shut off the inefficient cat code? Seems odd that it can turn off emissions certain codes but not others.

Also: Can someone explain this?

Misfire detection disabled to permit reduce mass rotating assemblies and further modifications. To my understanding, the misfire is detected when the crank position sensor expects a big boom to accelerate the crank on a power stroke TDC, but there is not an acceleration as expected. So if anything reduced mass would mask a misfire, not create one, right?

[Sniper]

To me it sounds like tuners can do everything like they used to with hptuners but Torrie is choosing not to.
My shop didn’t see any issues with doing whatever is needed with hptuners. They’ve already got some Gen Vs they’ve modified with more than I’m doing.

[Mikey]

To me it sounds like tuners can do everything like they used to with hptuners but Torrie is choosing not to.
My shop didn’t see any issues with doing whatever is needed with hptuners. They’ve already got some Gen Vs they’ve modified with more than I’m doing.

Yeah, it's the first time I'm hearing shops not being able to turn of 02 sensors etc. I just know certain tuners opt not to due to increasing emission crackdowns

[Jack B]

If your state has dynamic e-check, you cannot hide the tune

[VENOM-TA]

Mine is tuned with HP tuners by Prospeed in Houston.. I have ARH Headers, no cats and Corsa sport exhaust.. no issues, no CEL lights and passes emissions when plugged in to the OBDII port..

[Lawineer]

If your state has dynamic e-check, you cannot hide the tune

This makes a lot of sense. EPA has been cracking down.