DRAGRCR REDEYE REBUTTAL

[Phast Hemi]

A number of factors will cause the car to intervene and alter the commanded shift on the fly. Among them are tire pressure, track prep, trans, and traction control settings on the radio. These factors are unrelated to settings in the tune.

 

[Hellcat Cuda]

You guys, please help me out here. Unless there is an acknowledgement from FCA on this hicup, and therefore a reprogramming available from FCA, my dealership won't have a clue on this. I love my dealership, but I'm certain they won't be able to figure it out. And definately without taking it out and beating the crap out of it multiple times. I could even go up there and probably convince them for me to take the SRT tech out to duplicate it, but there really is nowhere very close that we could duplicate it without attracting the cops or risking some kind of accident with another vehicle. This last time I was out is the worst it's ever been. If you would be so kind as to specifically tell me what to do, I would REALLY appreciate it. BTW, my car is dead stock except for 18", 305x45 MT Rs running at 19lbs.

 

[DRAGRCR]

You guys, please help me out here. Unless there is an acknowledgement from FCA on this hicup, and therefore a reprogramming available from FCA, my dealership won't have a clue on this. I love my dealership, but I'm certain they won't be able to figure it out. And definately without taking it out and beating the crap out of it multiple times. I could even go up there and probably convince them for me to take the SRT tech out to duplicate it, but there really is nowhere very close that we could duplicate it without attracting the cops or risking some kind of accident with another vehicle. This last time I was out is the worst it's ever been. If you would be so kind as to specifically tell me what to do, I would REALLY appreciate it. BTW, my car is dead stock except for 18", 305x45 MT Rs running at 19lbs.

I really cannot help you. I consider a hiccup on the street to be normal. I did have a formal complaint that went high up in the engineering department at FCA and I was told the car was operating as designed INCLUDING the hiccups. But my complaint was a 1-2 hiccup on the race track with a good tire and a well prepped surface (no tire spin) and my car was a 2020.

I would take it to the dealer if you have not done so before and just make the basic complaint and see if there is a TSB etc.

I will tell you that I am relatively sure your car will work properly on the Drag Strip. BOTH 2019 RedEyes that I have data logs from short shifted the 1-2 shift. Then they went on to shift just short of 6300 on all the other shifts. So, no hiccups on the drag strip making passes. So I would not touch the tune in your car if it were me.

I do not know of anything being offered by FCA on this and like I said it really should not include 19's anyways if all my info is correct. I also have not seen a datal log from another 2020 or heard of any other 2020's hiccuping on the Drag Strip with a good tire and prep.

 

[Hellcat Cuda]

Well, if you hadn't heard of a '19 RE with the hiccup on the track, you have now. I was running at one of our local tracks that had a special event going on and the track was prepped pretty well. My MTs usually dead hook really well, so no problem with that (usually). In the beginning of tracking the car (last fall) it would hiccup very slightly and so minimal I didn't even notice at which shift(s). Now it hiccups pretty consistent at the track (it was pretty bad the last time out) and sometimes on the street (but I haven't been driving it real hard on the street). Maybe I should disconnect the battery for about a half hour and see if that will clear up any bad habits it has picked up.

 

[DRAGRCR]

Well, if you hadn't heard of a '19 RE with the hiccup on the track, you have now. I was running at one of our local tracks that had a special event going on and the track was prepped pretty well. My MTs usually dead hook really well, so no problem with that (usually). In the beginning of tracking the car (last fall) it would hiccup very slightly and so minimal I didn't even notice at which shift(s). Now it hiccups pretty consistent at the track (it was pretty bad the last time out) and sometimes on the street (but I haven't been driving it real hard on the street). Maybe I should disconnect the battery for about a half hour and see if that will clear up any bad habits it has picked up.

I would reset the adaptives by disconnecting both battery cables and shorting them together for 60 seconds. YOU MAY LOSE THE SRT PAGES so do this before going to the track. If you do lose them be patient they will eventually reappear after the info downloads and after a few ignition cycles. Also I would try different tire pressures etc. I have seen tracks hand spray the starting line and a car length or two and then do nothing for down track prep. You need to run at an event where they trailer spray the whole track and hopefully you witness this. Most of the time when you hook real good on the hit you think you are good to go, but not always.

MT published reccomendations the ET STREET R is reccomended 14 to 18 PSI Hot. So unless you are on max radial prep for the whole 1320 you are in trouble at 19 PSI. Maybe CALL MT and ask them what they think. And what if your gauge is off by a PSI or two? So try some things! And I am sure you know if you want 18 PSI Hot you need to be at 17 before your burnout if the tire is cold.

Right off their web site :
ET STREET™ R (RADIAL) AND ET STREET™ S/S
On the racetrack DO NOT use starting pressures below 13 psi.
Recommend pressures: 14-18 psi

 

[Hellcat Cuda]

Dragrcr, thank you very much for the input. So you're thinking the tires are breaking loose down the track? It doesn't sound or feel like it but I'm open to it being possible. Sure can tell when the stock tires break loose at 70mph on the freeway. I was not aware you could run the tires as low as 14. Wow. I will run them a little lower then, probably 17 or so and see if that makes a difference. Thanks again for the input.

Are you expecting the S/S to not have a hiccup even though it is essentially still a RE? Would be a pisser if they fixed on the newer models and don't go back with a TSB on the earlier cars. Keep us informed on the S/S.

 

[DRAGRCR]

Dragrcr, thank you very much for the input. So you're thinking the tires are breaking loose down the track? It doesn't sound or feel like it but I'm open to it being possible. Sure can tell when the stock tires break loose at 70mph on the freeway. I was not aware you could run the tires as low as 14. Wow. I will run them a little lower then, probably 17 or so and see if that makes a difference. Thanks again for the input.

Are you expecting the S/S to not have a hiccup even though it is essentially still a RE? Would be a pisser if they fixed on the newer models and don't go back with a TSB on the earlier cars. Keep us informed on the S/S.

If you go back and look closely at that TECH Bulliten that I got that info out of you will see that smaller tires and heavy cars use higher pressures. Example big Top Fuel tires use 6 PSI. Tires are huge and cars weigh very little. They break the weight at 3000 pounds and the size at 30". So your car is 3000 plus pounds (needs more pressure) and tire is smaller than 30" (needs more pressure). These values are needed to support the weight of the vehicle and keep the tire from squashing when you nail the throttle and all the weight transfers to the back tires. With that being said, I have used 14 in a Hellcat before without issues but the Demon did not like it. The Demon had more power (distorts the tire more) and it transfers more weight (squashes the tire). With the 315/50R17's on the Demon I tried to use 17 and above. With your car I would probably try to use 16 and above. But what if your gauge reads low? That is why I try things and I will go lower and try it. In NO CASE should the tire look flat. The tire should easily be supporting the weight of the Vehicle.

All cars lose traction down track, but most of the time it is very minimal so you are not aware. I was talking about the car losing traction on the shifts or at or near the gear shifts. I am not talking about a big spinning of the tires that will put the car sideways. This is why down track prep is so critical. It is hard to understand what is going wrong with the car and causing the Hiccup.

The S/S will have TCM programming similar to the Demon. I have experience with that car. Many times the car had a Hiccup and then I come back next week and it is fine. This tells me the track skimped on the prep on the bad week. Or it had rained and they did not compensate.

I have had times where the Demon hiccuped and then the next pass I saw them prepping right before I made that pass and it was fine. The prep really does have to be on point with these cars including down track. That's why I suggested you go to an event that ensures max prep like MSHS etc. Then you will know for sure.

If your car had a hiccup at the track I bet it was on the 2-3 shift. Data Logs show the 19's short shifting the 1-2 shift but the other shifts it is right below the rev limit.

YES, if you can run more pressure, by all means, DO IT. But don't be afraid to go down. I want to make good passes and I have learned to try things and adapt. EVERY time I make a hit I want to put up a good number. Every time.

Also lower pressures will make the tire spin on the rim more throwing off the balance. But I have a way of dealing with that at the track if necessary. So I do NOT let this affect what I am doing.

 

[Markp]

I have never ran my tires below 18psi. I usually start at 24-22 psi then equalize the tire pressure for both tires after every run and work my way down from there. I keep lowering pressure until the car stops hooking then I go up in pressure until it hooks again. Then I have the sweet spot and I leave it at that psi unless the track changes and I slip again. A little advice @moparjim gave me at the track. My best times are usually in the 19.5-21 psi range. Every track and every car is a little different. Remember my car is a 2.62 car so tire pressure won't always be the same for a 3.09 car.There is no set psi that will work for every car and every driver. It depends on track, weather, psi and your right foot.

 

[DRAGRCR]

I have never ran my tires below 18psi. I usually start at 24-22 psi then equalize the tire pressure for both tires after every run and work my way down from there. I keep lowering pressure until the car stops hooking then I go up in pressure until it hooks again. Then I have the sweet spot and I leave it at that psi unless the track changes and I slip again. A little advice @moparjim gave me at the track. My best times are usually in the 19.5-21 psi range. Every track and every car is a little different. Remember my car is a 2.62 car so tire pressure won't always be the same for a 3.09 car.There is no set psi that will work for every car and every driver. It depends on track, weather, psi and your right foot.

You run a heavy weight (needs more pressure) and a taller gear (less likely to spin so can use more pressure) and a smaller tire (needs more pressure). That Tech Bulletin does in fact say "16 psi and up" for the Radial Pro and others. But for the ET Street R it says 14 to 18. It does not say 14 and up. So I rarely run more than 19-20. With my Demon I ran 674 passes at 16 different tracks in 13 different states mostly on the 315/50R17 and some on the 305/45R17 and I usually would start at 18 and let it ride if it is hooking well. I have never had any issues down to 17 ever on the Demon with either tire. Not anywhere. Maybe my gauge reads low. The Demon would sometimes chatter the tires below 17. I ran the Hellcat down to 14.5 to 15 without any issues.

Also that Data Log from you shows the car having a hiccup on the 2-3 shift. Something to think about.

I want to be specific. I am not trying to sell lower pressures. I am just saying that it DOES work in some cases and is safe as reccomended by the actual folks that make the tires. Specifically this tire is not constructed the same as a race radial slick that since inception have used 18-22 psi.

I have heard many people talk about track outings and somewhere along the line the track prep goes away. Irwindale was typical and like this for many many years. Good initial prep and then they do absolutely NO touch up. Or some tracks they do not want to stop and do a proper re prep of the track. A LOT of guys just bitch and go home. Some really famous Guys on here. Well, I Stay and make passes and figure out how to get down the track. I also am not going to take any chances after I drive 1800 miles and have access to good DA and the real possibility of setting a PB or Record time. So, I typically start at 17 and work my way up if I have any question about the prep. Some track I know they are on point so I would start higher like 18 or so.

At Irwindale they just wanted the highest number of passes made as recorded by the Computer program running the timing system. And, it was about 80% hard street tires. So after a while the track would be COMPLETELY used up and covered with hard street tire rubber. If you looked closely the track surface would be grey, not black and it would actually shine from being polished by all the spinning tires. A dead track. By trying things I found out a way to make good passes. Stomp the throttle hard to the floor in my Hellcat with 309 gears and the 305/45R 18 ET Street R's. The car would hook and it would 60 foot and ET within .02 or .03 of a perfectly prepped track. It worked and the time on the score board would be pretty much the same as what people are used to seeing from my car. NOTE: This would NOT work if the track had any grip. It had to be dead.