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View Full Version : Ran my SRT-4 today - mixed results



ScottD
06-30-2010, 01:11 AM
I ran my SRT-4 today at Mason Dixon during SDAC. This was my first time on slicks, and while I still can make more improvement, I was pretty pleased with how I did driving wise. My last several runs were all 1.98-2.01 60ft times and the ets ranged from 14.02-14.18. I really enjoyed running on the slicks.

Unfortunately the MPH on the car was down from the past two times at the track. Bone stock it ran 14.4 at 97mph and w/ Stage 2 (no toys) and MP exhaust it ran 14.2 at 99mph on a very hot day at Cecil. Today my MPH ranged from 93.5-96.8, quite a bit less than I was hoping for. I was hoping with a good launch to get 101-102mph.

The MPH decrease is puzzling to me because there were no codes when I checked them. I also have all my vac lines zip tied and did a boost leak test about a week ago and had no issues.

Something is a tad off with the car. Thoughts as to where to start trouble shooting?

trbowgn
06-30-2010, 06:59 AM
Were the slicks shorter than the tires you were running with your higher MPH

Keito
06-30-2010, 07:52 AM
I watched your runs, I say bad gas,(lower octane), resulting in
reduced timing.
My stage 2 car with drag radials has run 13.50's, on a well prepped
track.

Captain Chaos
06-30-2010, 08:06 AM
How come so many stage 2 cars run seemingly so slow? That seems like a disappointing time for the money. When I had my stage 1 car it ran 13.4 @ 102 on DR's. Not bragging just wondering why that is?

ScottD
06-30-2010, 04:54 PM
I watched your runs, I say bad gas,(lower octane), resulting in
reduced timing.
My stage 2 car with drag radials has run 13.50's, on a well prepped
track.

I always run 92-93 octane in the car. Maybe next time I should splash some race gas in. Pat Culkin made a pass in the car and he also said it felt like it was pulling timing.


Were the slicks shorter than the tires you were running with your higher MPH

Yes, I am running 23s on 15in wheels compared to whatever the stock 17s w/ 205/50/17.

Keito
07-01-2010, 07:34 AM
Are you running the stock exhaust/cat?
I should have added I always splash a few gallons of 108 @ the track.
Now that I have Stage 2 with toys, I try to get to the track with 1/4 tank of
93 then add 2-3 gallons of 108.
My best pass has been 12.95 with DR's and an open downpipe running
High Octane Mode.

contraption22
07-01-2010, 08:12 AM
23's are way too short, Scott. Mine never ran well on them. the 24.5's make a huge difference.

Pat
07-01-2010, 08:18 AM
23's are way too short, Scott. Mine never ran well on them. the 24.5's make a huge difference.

That may be the case, but there is something that was not happy with the car. When i ran it, it launched well, I cut a 1.86 (?) 60 foot, hit second at about 5600 rpm and the car fell on it's face. It was a dog for about a second, then it took off. It did not pull nearly as hard as my old stock SRT did.

It very much felt like it pulled a bunch of timing for some reason.

contraption22
07-01-2010, 08:35 AM
Mine sometimes acts that way on anything less than 93 octane.

Also, I discovered this weekend, I had an issue with spark plugs. I borrowed a used set from steve and the car ran way better. If your car has copper core plugs, you really have top change them often.

ScottD
07-01-2010, 08:38 AM
Are you running the stock exhaust/cat?


I have stock cat but the MP cat back exhaust on it.


23's are way too short, Scott. Mine never ran well on them. the 24.5's make a huge difference.

I had 24.5s for it that I sold because they wouldn't fit on the GLHS and I wanted one set of slicks to use on all three turbo cars. I know the 23s are not ideal, but I didn't think they would make that much of a difference, maybe I was wrong on that count.


That may be the case, but there is something that was not happy with the car. When i ran it, it launched well, I cut a 1.86 (?) 60 foot, hit second at about 5600 rpm and the car fell on it's face. It was a dog for about a second, then it took off. It did not pull nearly as hard as my old stock SRT did.

It very much felt like it pulled a bunch of timing for some reason.

Yes it was a 1.86 compared to my 1.98-2.01s I was cutting. I knew you would make a cleaner pass than would but the MPH on your pass was 95.5, same as what I was running.

ScottD
07-01-2010, 08:40 AM
Mine sometimes acts that way on anything less than 93 octane.

Also, I discovered this weekend, I had an issue with spark plugs. I borrowed a used set from steve and the car ran way better. If your car has copper core plugs, you really have top change them often.

I'll have to check the plugs again, but I'm pretty sure I put NGKs in when I put the stage 2 on. The car is an 2004 but has almost 20k on it, maybe plug wires wouldn't hurt at this point either.

contraption22
07-01-2010, 08:48 AM
My OE wires started failing at around 7000 miles.

1BADVAN
07-01-2010, 11:46 AM
MPH is based on horsepower to weight ratio the tire sizes shouldn't change it that much, just the acceleration and times, For example my friend with a 79 trans am was running 15.7@94mph with 2.73 gears then switched to 3.73 gears and ran 14.2 at the same 94mph. Drag cars use gears and tires size to set it up so you are near redline in top gear while crossing the finis line. the only reason to go bigger on tires is to increase traction or if you are running out of gears.

Like some guys are saying whether it is octane, or just corrected altitude for the day you are just not making as much power but the increased traction helped your ETs. I also say check your ignition +1 on checking copper plugs.

Keito
07-01-2010, 11:58 AM
Someone asked me and I didn't know, what was the altitude @ the
drag strip?

MILKCARTON
07-01-2010, 12:10 PM
Someone asked me and I didn't know, what was the altitude @ the
drag strip?

That doesnt make a bit of difference, ask anyone on this forum, in fact it is easier for turbo Dodges to run at alttitude.

Murphy
07-01-2010, 02:44 PM
elevation is 550 feet.

cecil is 320 feet

DodgeZdad
07-01-2010, 02:56 PM
Stage 2 runs rich, buy a diablo sport and AF meter and run 12's with those slicks.

1BADVAN
07-01-2010, 05:23 PM
That doesnt make a bit of difference, ask anyone on this forum, in fact it is easier for turbo Dodges to run at alttitude.

I highly disagree, living in SLC utah (4400 ft) my car runs decent, but even going to vegas (2200 ft) The cars stick you in the seat way more and the drag times were .5+ faster at the drag strip.

I have heard with certain setups things are not effected as much but we like going down in altitude, cause its faster

jl93sundance
07-02-2010, 12:54 AM
Stage 2 runs rich, buy a diablo sport and AF meter and run 12's with those slicks.

Just ran a 12.9 @ 109 with slicks +dsp tonight.

ScottD
07-02-2010, 07:48 AM
Mike Marra mentioned the diablo sport to me when we were talking at the track and I think he also said Steve Menegon runs it.

I think I will try and get it sorted out first before changing things, but that might be an option.

Captain Chaos
07-02-2010, 09:43 AM
I highly disagree, living in SLC utah (4400 ft) my car runs decent, but even going to vegas (2200 ft) The cars stick you in the seat way more and the drag times were .5+ faster at the drag strip.

I have heard with certain setups things are not effected as much but we like going down in altitude, cause its faster

Pressurized cars aren't as affected by altitude but it still affects them. Watch the western swing of NHRA coming up and they always talk about the TF cars not being as affected as the Pro Stock cars. But its because they adjust the blower and fuel for the lack of oxygen. The pro stocks can rejet the carbs but its not apples to apples.

1BADVAN
07-02-2010, 09:53 AM
Pressurized cars aren't as affected by altitude but it still affects them. Watch the western swing of NHRA coming up and they always talk about the TF cars not being as affected as the Pro Stock cars. But its because they adjust the blower and fuel for the lack of oxygen. The pro stocks can rejet the carbs but its not apples to apples.

exactly my big block car saw even more of a difference changing altitudes

Keito
07-02-2010, 11:04 AM
Mike Marra mentioned the diablo sport to me when we were talking at the track and I think he also said Steve Menegon runs it.

I think I will try and get it sorted out first before changing things, but that might be an option.

If you get the USB cable with the tuner,(its an extra $30), you can
also datalog with it.
Kinda nice to see if you are pulling timing.

ScottD
07-02-2010, 12:08 PM
If you get the USB cable with the tuner,(its an extra $30), you can
also datalog with it.
Kinda nice to see if you are pulling timing.

So I take it you would run the diablo sport with the stock computer and injectors?

Keito
07-02-2010, 02:16 PM
Correct.
If I recall, the 93 octane tune which they include dynoed
+30 hp and +60 torque.
It came out in the fall 2008, there was a vendor on SRTForums that bought
one and tried it.
You can add Stage 2 injectors and a stiffer wastegate actuator, but
will need to get the cal rescaled for them.
PTPerformance is one of the more popular vendors.

contraption22
07-03-2010, 08:28 AM
Scott,

You can go to a DiabloSport CMR dealer/tuner, and they can give you a custm tune on the Predator to take full advanatage of your 3 bar sensors and s2 injectors.

To give you sopme perspective of how conditions were less than idea on Wednesday, I was running 3-5 tenths slower than expected. And Steve's SRT-4, with the Diablo Sport, 3 bar sensors, upgraded intercooler and turbo, was only running 13.5 on slicks. That car would probably be in he 12's at Cecil.

ScottD
07-03-2010, 09:51 AM
Scott,

You can go to a DiabloSport CMR dealer/tuner, and they can give you a custm tune on the Predator to take full advanatage of your 3 bar sensors and s2 injectors.

To give you sopme perspective of how conditions were less than idea on Wednesday, I was running 3-5 tenths slower than expected. And Steve's SRT-4, with the Diablo Sport, 3 bar sensors, upgraded intercooler and turbo, was only running 13.5 on slicks. That car would probably be in he 12's at Cecil.

This makes me feel a little better. I ran the car once at Cecil with the S2 on street tires and it was trapping 99 that day. But then again, Cecil always seems faster, as Pat likes to call it "the magic of Cecil".

1qk4dr
08-18-2010, 10:55 PM
I went from a K&N Typhoon and added a 93 DSP tune to the car and picked up 33whp and 45lbs of torque. Also added 5 mph on my trap speed. The car went from 10:1 a/f to 11.77-12 a/f.

14.198@98 mph K&N
13.9@103 + DSP 93 tune

slasky
08-18-2010, 11:42 PM
Mine ran 13.9 at 99 mph 100% bone stock on stock tires.

ScottD
10-09-2010, 04:29 PM
Ran again today. It was hot ... again. Ran a best of 13.73 at 99.4mph. Mph was 98-100. I installed new plugs/wires and tightened all the IC pipes after the runs at SDAC, that helped. Would like to see 102-103mph, might throw in a little race gas next time I run it, might still be pulling a little timing due to the heat (it was about 85 or so today).

contraption22
10-09-2010, 08:36 PM
Are you tunning 91, 92 or 93 fuel?

ScottD
10-10-2010, 12:52 AM
I always run premium. Most of the time its 92, sometimes its 93 depending on where I've gotten gas.

contraption22
10-11-2010, 01:12 PM
try 93 octane. Makes a difference on my car.

ScottD
10-11-2010, 04:25 PM
try 93 octane. Makes a difference on my car.

I'll try that if I can find it around here, or some race gas.

More troubling was the slit that developed in the sidewall of the slick, I need to take a pic of that, the slicks have only 13 runs on them.:mad:

jl93sundance
10-11-2010, 04:36 PM
how much boost are you running again?

ScottD
10-11-2010, 07:36 PM
In the heat in 3rd it is spiking to 20 and holding 16-17.

1qk4dr
11-08-2010, 10:17 PM
Just ran a 12.9 @ 109 with slicks +dsp tonight.
What do you have done to your srt?

jl93sundance
11-10-2010, 07:03 PM
What do you have done to your srt?

3in 02 back exhaust with cat (no cat anymore but when I ran it), bigger front mount ic, act clutch, dsp tune @ 20-21psi, slicks of course, thats it engine wise I think...koni adjustable shocks/eibach springs and solid motormount inserts...

1qk4dr
11-17-2010, 01:09 PM
3in 02 back exhaust with cat (no cat anymore but when I ran it), bigger front mount ic, act clutch, dsp tune @ 20-21psi, slicks of course, thats it engine wise I think...koni adjustable shocks/eibach springs and solid motormount inserts...


Hmm, I'm thinking about getting an 3" Thermal Turboback. It looks like you're trapping 3-4 mphs quicker than I with just a FMIC and 3" Exhaust on top of what I have. Did you notice any big difference with the IC and/or exhaust?

2004 Srt-4 13.351@105.89 DR's DSP, Typhoon, & 225/50/15 BFG DRs

contraption22
11-17-2010, 01:30 PM
This past weekend I ran my SRT-4 at Cecil, with some borrowed 24.5 x 8 M/T slicks. These slicks weren't as sticky as the M&H's, but once I got them hot, they worked well.

Best run of the day was a 13.21 @ 105mph with a 1.79 60ft time.
Mods to the car are Mopar downpipe and catback, S2/toys on high octane mode. ~5gallons of 92 + 2 gallons of 110. FM Enforcer E1 turbo. Stock everything else, unless you want to count the K&N Drop-in filter. I was hoping for better. But oh well.

I've had an upgraded intercooler for this car for almost a year and haven't gotten the opportunity to install it. I'd like to get around to doing it sometime soon. I have also heard that the Diablo Predator works well with the S2 PCM, so I maybe eventually try that.

I should also mention, I always granny shift it. I know some have had good results results with WOT shifting these cars, but I am not gonna try.

contraption22
11-17-2010, 03:21 PM
This makes me feel a little better. I ran the car once at Cecil with the S2 on street tires and it was trapping 99 that day. But then again, Cecil always seems faster, as Pat likes to call it "the magic of Cecil".

Forgot to mention, when your 60ft goes down as yours did when you bolted the slicks on, so will your trap speed.

My car has run as fast as 107mph on street tires. Doesn't ET worth crap tho.

Pat
11-17-2010, 05:40 PM
Forgot to mention, when your 60ft goes down as yours did when you bolted the slicks on, so will your trap speed.

My car has run as fast as 107mph on street tires. Doesn't ET worth crap tho.

What was the full breakdown of your 13.21 run?

contraption22
11-17-2010, 05:44 PM
I will post the timeslip tonight. By my luck, I posted the breakdown of my previous best with this car from that day at Englishtown back in 2006. I will post the slips side by side tonight.

I have a theory.

contraption22
11-18-2010, 02:02 PM
What was the full breakdown of your 13.21 run?

http://www.turbo-mopar.com/forums/showthread.php?t=54345