[Jpick]

I upgraded the cat a little, and I have my concerns. Kinda unsure how to feel about it. I did a 2.85 pulley, demon 1000cc injectors, 180 t-stat, unlocked ECU, Trinity T2 tuner, and email tunes, all purchased from HHP. Before upgrades, using the “onboard dyno” in the performance pages, the best I saw was 718hp. After upgrades, which I believe should have added around 150hp, the best I’ve gotten after multiple runs on the street, is 670’s. Makes ZERO sense to me, and I’m completely at a loss right now. I’m thinking of maybe taking it to an actual dyno, hours away, and not free, but I’m almost afraid I would leave more disappointed than what I already am. Yes the car feels quicker, reminds me of my other cars after the tuner makes the throttle blade open wider sooner. Sometimes it feels like it’s maybe pulling a little harder, but not close to what I’d expect from 100 - 150 extra ponies. Have 93 octane tune, no trans tune, shifts amazing from factory. Thoughts, opinions, advice?? Thanks!

 

[Vet Rider]

I upgraded the cat a little, and I have my concerns. Kinda unsure how to feel about it. I did a 2.85 pulley, demon 1000cc injectors, 180 t-stat, unlocked ECU, Trinity T2 tuner, and email tunes, all purchased from HHP. Before upgrades, using the “onboard dyno” in the performance pages, the best I saw was 718hp. After upgrades, which I believe should have added around 150hp, the best I’ve gotten after multiple runs on the street, is 670’s. Makes ZERO sense to me, and I’m completely at a loss right now. I’m thinking of maybe taking it to an actual dyno, hours away, and not free, but I’m almost afraid I would leave more disappointed than what I already am. Yes the car feels quicker, reminds me of my other cars after the tuner makes the throttle blade open wider sooner. Sometimes it feels like it’s maybe pulling a little harder, but not close to what I’d expect from 100 - 150 extra ponies. Have 93 octane tune, no trans tune, shifts amazing from factory. Thoughts, opinions, advice?? Thanks!

That in car dyno is a gimmick. Turn that crap off and enjoy the car. There is no actual HP measurement going on. Just preset tables the car displays at certain conditions that should match what they claim is the factory HP.

 

[Vet Rider]

Oh and a trans tune is a HUGE upgrade for these cars. I have a completely stock car with a tune only and trans tune and it made a huge difference. Get that trans tuned.

 

[Jpick]

That in car dyno is a gimmick. Turn that crap off and enjoy the car. There is no actual HP measurement going on. Just preset tables the car displays at certain conditions that should match what they claim is the factory HP.

That is kind of what I was thinking, and definitely hoping to confirm.

Oh and a trans tune is a HUGE upgrade for these cars. I have a completely stock car with a tune only and trans tune and it made a huge difference. Get that trans tuned.

For almost every mechanic/tuner that I found that says do the trans tune, I've found one that swears it is not good for the transmission, and will cause premature failure. All from online sources of course. Youtube dyno shops and what not.

As far as the upgrades go, in my opinion only, no stats on paper or anything to show, I would compare this upgrade that cost me about $4000 in parts, equivalent to about $300 - $500 in parts worth about 35 - 50hp gains on my 3 previous corvettes. I know the power to weight ratio and all that crap, but I'm talking seat of the pants improvements, this is the biggest disappointment I can recall in my 48 years of living, if I'm honest. I am ZERO PERCENT impressed, for the money spent. I believe I'll bite the bullet, and throw more money at a dyno machine, just so I will KNOW how bad of an investment it was, but if it wasn't for the simple fact that this vehicle is so impressive as a 4 door sedan from the factory, I'd go back to Corvette in a "heartbeat". But, you know, Hellcats started popping up closer to home once I had mine, so there was NO WAY I was chancing not having the fastest one in the area! I am just highly disappointed, in case I haven't made that clear, or it is not obvious enough. I appreciate your input, thanks Vet!

 

[Spartacus]

Don't discount an incorrect tune.

The parts may be there, but if the tune is incorrect you won't see much improvement.
Kinda sounds like what's going on.

You watch Cleetus McFarland at all?

They are all the time tweaking their tune and half the time they get it wrong. lol

 

[Vet Rider]

Don't discount an incorrect tune.

The parts may be there, but if the tune is incorrect you won't see much improvement.
Kinda sounds like what's going on.

You watch Cleetus McFarland at all?

They are all the time tweaking their tune and half the time they get it wrong. lol

I'd doubt that with HHP. They are among the best in the business with hellcats.

 

[Spartacus]

I'd doubt that with HHP. They are among the best in the business with hellcats.

Experts make mistakes too.

Wouldn't hurt to double-check with them.

 

[Vet Rider]

Experts make mistakes too.

Wouldn't hurt to double-check with them.

They will need a data log. You will need to get a laptop with HP tuners installed and the MVPI2+ obd2 plug and cable. Then you can do a rip and record it to send in and see whats what.

 

[Jpick]

Don't discount an incorrect tune.

The parts may be there, but if the tune is incorrect you won't see much improvement.
Kinda sounds like what's going on.

You watch Cleetus McFarland at all?

They are all the time tweaking their tune and half the time they get it wrong. lol

Ole Cleetus! Hell yeah brother! 😁 I probably haven’t watched him since he first built “Leroy”. Based off HHP reputation, I don’t believe it’s simply in the tune, but never ruling it out. That is why I’m thinking take it to dyno. The 15 lbs boost is there, the A/F is running correct, but I just don’t believe it is where it should be for the parts installed. Thanks for your response!

They will need a data log. You will need to get a laptop with HP tuners installed and the MVPI2+ obd2 plug and cable. Then you can do a rip and record it to send in and see whats what.

I actually had Josh write me a 91 daily tune, basically just make it run correctly with new boost and injectors, and then I also bought a 93 tune, and he had me logging with laptop and T2. I may try running a log, and send to him for “diagnosis” and see if he can’t get me hooked up. Hopefully without costing me more $$$, since I bought multiple tunes.

 

[fumanchu182]

Experts make mistakes too.

Wouldn't hurt to double-check with them.

Yes they do, had another well known tuner almost yeet my trans. Now I tune it myself.

They will need a data log. You will need to get a laptop with HP tuners installed and the MVPI2+ obd2 plug and cable. Then you can do a rip and record it to send in and see whats what.

Diablo which is what OP has can do logs. Diablo data viewer can be used to view the logs and send to HHP.

 

[Unavowed]

There are plenty of 4 door LS/LT powered cars out there..
Ideally the car would be baseline dyno'd, then upgraded, then dyno'd again.
I've never been a fan of remote/mail order tuning. That may be good enough to start and gently drive the car to a shop for an in person dyno/street tune, but I wouldn't want the mail order tune to be my final tune.

 

[Jpick]

There are plenty of 4 door LS/LT powered cars out there..
Ideally the car would be baseline dyno'd, then upgraded, then dyno'd again.
I've never been a fan of remote/mail order tuning. That may be good enough to start and gently drive the car to a shop for an in person dyno/street tune, but I wouldn't want the mail order tune to be my final tune.

I actually never was either, but I had great experiences with a couple vettes, and it is almost impossible to get to a dyno around here. I’m in the bootheel of swamp a$$ Missouri. But also, I’m not a track guy. I may run down the 1/8th once or twice, just to see what’s what, but that is rare. Haven’t been since the mods, but I plan to when they open back up and have a test-n-tune session for 1, maybe 2 passes, whatever the results. Daily driver tires and all. Thanks for the response!

 

[motorheadmike]

That in car dyno is a gimmick.

There is no actual HP measurement going on.

Just preset tables the car displays at certain conditions that should match what they claim is the factory HP.

Got proof?

 

[HC5120]

I upgraded the cat a little, and I have my concerns. Kinda unsure how to feel about it. I did a 2.85 pulley, demon 1000cc injectors, 180 t-stat, unlocked ECU, Trinity T2 tuner, and email tunes, all purchased from HHP. Before upgrades, using the “onboard dyno” in the performance pages, the best I saw was 718hp. After upgrades, which I believe should have added around 150hp, the best I’ve gotten after multiple runs on the street, is 670’s. Makes ZERO sense to me, and I’m completely at a loss right now. I’m thinking of maybe taking it to an actual dyno, hours away, and not free, but I’m almost afraid I would leave more disappointed than what I already am. Yes the car feels quicker, reminds me of my other cars after the tuner makes the throttle blade open wider sooner. Sometimes it feels like it’s maybe pulling a little harder, but not close to what I’d expect from 100 - 150 extra ponies. Have 93 octane tune, no trans tune, shifts amazing from factory. Thoughts, opinions, advice?? Thanks!

That combo is 740ish to the tire at sea level. My car at about 4500 DA ran 7.41 in the 1/8 stock, 7.24 with PCM and TCM tune, and 6.80 with 2.85, 1050 injectors, spacer plates and HHP tune. Went from 99 mph to 104.5 in the 1/8. It will run in the 6.70s this year I am sure, on 93 octane for all of the above.

I don't trust butt-o-meter when it comes to cars.

There are tons of hellcats racing with trans tunes and pushing these cars very hard. This is a solid platform.

 

[Jpick]

That combo is 740ish to the tire at sea level. My car at about 4500 DA ran 7.41 in the 1/8 stock, 7.24 with PCM and TCM tune, and 6.80 with 2.85, 1050 injectors, spacer plates and HHP tune. Went from 99 mph to 104.5 in the 1/8. It will run in the 6.70s this year I am sure, on 93 octane for all of the above.

I don't trust butt-o-meter when it comes to cars.

There are tons of hellcats racing with trans tunes and pushing these cars very hard. This is a solid platform.

So, 5 more lbs of boost, bigger injectors, and a tune are good for about 75 wheel hp?? Seems low to me, but I’m brand new to boost, and no expert on any matter of mechanics. But I ran a couple “samples” today since it was 72 degrees here, and I showed a 7.2, and a 6.7 1/8th on 93 with Continental Extreme Contact tires, and spun basically all of 1st and most of 2nd. So our times are fairly in line I guess. Might could get a 6.5 on a track on a GOOD pass, maybe. Thanks for the response!

 

[rayzazoo]

So, 5 more lbs of boost, bigger injectors, and a tune are good for about 75 wheel hp?? Seems low to me, but I’m brand new to boost, and no expert on any matter of mechanics. But I ran a couple “samples” today since it was 72 degrees here, and I showed a 7.2, and a 6.7 1/8th on 93 with Continental Extreme Contact tires, and spun basically all of 1st and most of 2nd. So our times are fairly in line I guess. Might could get a 6.5 on a track on a GOOD pass, maybe. Thanks for the response!

Going by Dodge’s #’s

707 stoc
747 2lbs boost (Direct Connection Stage 1)

~20hp per 1 lb boost

 

[Linda's Hell Cat]

Have a couple of questions for you?
While having extra HP what SRT settings are you using?

How long have you had the extra HP?
Are all your tests all on the Streets?

How does that hook up for you?

Linda

 

[Jpick]

Have a couple of questions for you?
While having extra HP what SRT settings are you using?

How long have you had the extra HP?
Are all your tests all on the Streets?

How does that hook up for you?

Linda

I’ve tried basically EVERY setting combo.
I’ll probably catch a LOT of heat for this one, but to each their own. The combo that I get MY best results from, are set everything to track, and then put traction to street, and suspension to street. The softer ride setting seems to work better due to the weight transfer. That is my opinion, and seems to yield best results on the streets, for me anyway.

I did the mods late last summer. The car is not a daily, and I don’t get out in it as much as I’d like to, mainly thanks to this bipolar Southeast Missouri weather!

Yes, all my tests are on the streets. If I ever try someone, or get tried, it will be on the street, so strip testing really doesn’t mean much to me.

And lastly, it hooks probably about exactly as you’re thinking it does. Like the street tires are coated with Vaseline! Lol! But I don’t just mash it to the floor and let it eat, that’s actually something I’m ALWAYS trying to improve. My launch. I never, ever use launch control, by the way, forgot to mention that in the settings part, sorry. I pedal best I can like D-Bo is after me and he wants my new bike! Thanks Miss Linda!

 

[Linda's Hell Cat]

"I pedal best I can like D-Bo is after me and he wants my new bike! "

OK, Let me ask you this now, what tires are you using?

What year is your Hellcat?

Linda

 

[Jpick]

"I pedal best I can like D-Bo is after me and he wants my new bike! "

OK, Let me ask you this now, what tires are you using?

What year is your Hellcat?

Linda

Actually, I think I said Extreme Contacts earlier, but that’s incorrect. I ended up going with Goodyear Exhilarate tires this time. And it is a 2016 model.