Duramax math

[05lly2500hd]

ok, I've been viewing some old videos of mine from a grudge match non timed track. I haven't had it to a timed track in a while.
Viewing the videos, I keep coming up with somewhere around 9.3 to 9.5 and it was a 1/8 mile supposedly. I remember I hit right at 88-90mph. But from looking around that equates to a 14 sec 1/4 and that just ain't right.

I know I know, I need to get this thing back to the track, possibly this week.
But what gives? I'm roughly 7400# with me in it and 1/2 tank, the twins and the best tune I have....In the videos I was stomping on trucks, a Z06, Viper, etc.

Maybe I'm just anxious, who knows. But it's eating me up since I actually time the video with a timer and not the second counter on youtube.
????

Is there a rule of thumb to use for ET between 1/8 mile, 1/4 mile etc.?

 

[05lly2500hd]

to view the videos you can go to youtube.com and in search bar enter ...."hollyandjeromy"

 

[racinmike77]

You have the MPH to run in the 12s, long time no see jeromy glad to see everything is working out and the truck is running. With your MPH and slow ET im guessing your 60ft is lacking, are you launching in 2wd?

 

[TrentNell]

@ 90 mph you could run 11's with a good enough 60 ft , i have went 7.3 in the 1/8 @ 91 mhp , that equated to my 11.63 run . Get that thing to the track and let her eat

 

[05lly2500hd]

You have the MPH to run in the 12s, long time no see jeromy glad to see everything is working out and the truck is running. With your MPH and slow ET im guessing your 60ft is lacking, are you launching in 2wd?

Ran 10, lost 1. ran 4wd on all but one and it wasn't the one I lost. I'm gonna have to spiffy up my tuning.
I ran a Z06, a Viper and all, they looked like they were trying, lol. I'm not really even sure if that was a true 1/8 mile, it was at a small airstrip.
Maybe I can make it Wed. or Sat to the local dragway in Gulfport.

 

[05lly2500hd]

went to the track tonight. I'm not happy. Actually pretty upset!

 

[TrentNell]

went to the track tonight. I'm not happy. Actually pretty upset!

what were the times ?

 

[wikdlmm]

Times????

 

[05lly2500hd]

I suck!

It was a bracket race at the Gulfport Dragway.
I emptied the truck best I could, except for the tool box with about 150lbs of junk, maybe less. 3/4 tank of fuel. Ran 12 times, the 12th time was first round of elimantion and I lost by .26 .

Tow Haul seemed to make me slower, all runs but one were in 4HI, the one 2wd run was embarrassing. I took out my headlight, folded in the mirrors, left the tailgate on and up. Took the TBar bolts all the way out.

OK, ok, ok.

The best I could muster was a 13.75@98mph, with a 60' of 1.89
The worst besides the 2wd was a 14.74@91mph with a 60' of 2.03

I definately need to work on my 60', most of them were around 2.00, only think I changed later in the game was taking 10psi out of each tire which seemed to give me .01 in the quarter, lol.
Only once was I able to watch the boost gauge and it DID NOT register boost while I was holding the brake in with all my might, around 2200 rpm. Very shortly after I left i seen it shoot up to 35psi or so, very odd because I've seen 60 easy before. I haven't seen any boost leaks.
I do have a bad driver's side hub assembly and DO NOT have cognito braces.
I have clamps on the front of my rear springs, pretty tight.
Tires suck, nitto terra grapplers, 285/60/18.
I honestly believe I need a better tune.
The tune I ran most everytime was one from Bobo, from a long time ago, back when I had the first twin setup and it's been tinkered on a time or two, by myself and another.
Need to check my fluid in front diff, as I forgot to hit 2HI and turning off track it was clunking/grinding pretty bad.
If I need to add each slip I will, it will just take me a while but I'll give a quick run down and let you guys' eyes rest, sorry so long. BUT I"m pissed, what am I doing wrong?

I'll list these as which run, 60', 1/4 ET, then 1/4 mile mph:


1
2.20
14.11
98.86

2
1.99
13.76
99.27

3
1.99
13.89
98.51

4 (2wd)
2.7
14.93
98.66

gonna skip the rest except for the best run here:
60' 1.89
1/8 ET 8.73
1/8 mph 78.56
1/4 ET 13.75
1/4 mph 98.08


Majority of my runs were around 13.88 at a mph of 98.

What gives?

I'm guessing I'm weighing around 7600 lbs tonight.

 

[paint94979]

It was a bracket race at the Gulfport Dragway.
I emptied the truck best I could, except for the tool box with about 150lbs of junk, maybe less. 3/4 tank of fuel. Ran 12 times, the 12th time was first round of elimantion and I lost by .26 .

Tow Haul seemed to make me slower, all runs but one were in 4HI, the one 2wd run was embarrassing. I took out my headlight, folded in the mirrors, left the tailgate on and up. Took the TBar bolts all the way out.

OK, ok, ok.

The best I could muster was a 13.75@98mph, with a 60' of 1.89
The worst besides the 2wd was a 14.74@91mph with a 60' of 2.03

I definately need to work on my 60', most of them were around 2.00, only think I changed later in the game was taking 10psi out of each tire which seemed to give me .01 in the quarter, lol.
Only once was I able to watch the boost gauge and it DID NOT register boost while I was holding the brake in with all my might, around 2200 rpm. Very shortly after I left i seen it shoot up to 35psi or so, very odd because I've seen 60 easy before. I haven't seen any boost leaks.
I do have a bad driver's side hub assembly and DO NOT have cognito braces.
I have clamps on the front of my rear springs, pretty tight.
Tires suck, nitto terra grapplers, 285/60/18.
I honestly believe I need a better tune.
The tune I ran most everytime was one from Bobo, from a long time ago, back when I had the first twin setup and it's been tinkered on a time or two, by myself and another.
Need to check my fluid in front diff, as I forgot to hit 2HI and turning off track it was clunking/grinding pretty bad.
If I need to add each slip I will, it will just take me a while but I'll give a quick run down and let you guys' eyes rest, sorry so long. BUT I"m pissed, what am I doing wrong?

I'll list these as which run, 60', 1/4 ET, then 1/4 mile mph:


1
2.20
14.11
98.86

2
1.99
13.76
99.27

3
1.99
13.89
98.51

4 (2wd)
2.7
14.93
98.66

gonna skip the rest except for the best run here:
60' 1.89
1/8 ET 8.73
1/8 mph 78.56
1/4 ET 13.75
1/4 mph 98.08


Majority of my runs were around 13.88 at a mph of 98.

What gives?

I'm guessing I'm weighing around 7600 lbs tonight.

For lack of a better word Inadequate tuning plain and simple. Get rid of those tires if you are serious about racing. They will only hold you back

 

[KEVINL]

MPH is way low What kind of tune are you running


I have ran 103 mph with the stock turbo

 

[paint94979]

MPH is way low What kind of tune are you running


I have ran 103 mph with the stock turbo

you should def. be able to run 114-118 and mid to high 11's with your current mods... What is your elevation? DA?

Edit. Just saw your weight is 7600... and i thought you have dual cp3's my apologies... you could easily drop 600-700 lbs right there that is .3-.4 and several MPH. Get ahold of Idaho Rob or Pat... pay the small fee of a few hundred bucks and have them build you a proper tune for your current truck setup my guess you will be EXTREMELY surprised at what you get

 

[05lly2500hd]

MPH is way low What kind of tune are you running


I have ran 103 mph with the stock turbo

To be honest I have a DSP5 switch and have left it on the #3 position which FEELS the fastest. I got a tune from Bobo (embarrassingly enough like almost 3 years ago) I've played with it and 05LLY from PA has tinkered with it.
My laptop has crashed and I'm on a borrowed one now(I sure have a shitty time with laptops crashing) so I'll have to upload tunes in my truck to a pc and go from there.

 

[05lly2500hd]

you should def. be able to run 114-118 and mid to high 11's with your current mods... What is your elevation? DA?

Edit. Just saw your weight is 7600... and i thought you have dual cp3's my apologies... you could easily drop 600-700 lbs right there that is .3-.4 and several MPH. Get ahold of Idaho Rob or Pat... pay the small fee of a few hundred bucks and have them build you a proper tune for your current truck setup my guess you will be EXTREMELY surprised at what you get

That's why I'm so dissapointed! Over $30k in this thing and to run a 13? I know I know should have gotten off my ass and to the track more. But this has really got me down....where's the beer drinking smiley? But I woop soo much ass on the street it's hilarious, I just don't get it.
I have no idea what DA means, I wanted to ask the techs what it was but didn't wanna look like a dumbass. I can check the elevation. I'm sure it's close to sea level as I'm in gulfport close to the gulf.

 

[05lly2500hd]

elevation 19 feet. It was pretty warm outside all day around 90* and fair amount of humidity. Didn't hear the fan I don't think but it almost feels like the fan was on, as it always drains power.

 

[05lly2500hd]

you should def. be able to run 114-118 and mid to high 11's with your current mods... What is your elevation? DA?

Edit. Just saw your weight is 7600... and i thought you have dual cp3's my apologies... you could easily drop 600-700 lbs right there that is .3-.4 and several MPH. Get ahold of Idaho Rob or Pat... pay the small fee of a few hundred bucks and have them build you a proper tune for your current truck setup my guess you will be EXTREMELY surprised at what you get

on your edit..........where can I drop 600-700 pounds? even so, .4 is not much on a 13.75, but I do see your point.

I've been trying to get a tune or a few, still working with Rob on it.
I don't think Pat likes me anymore, lol.

Hey Pat..............:hug:

 

[paint94979]

That's why I'm so dissapointed! Over $30k in this thing and to run a 13? I know I know should have gotten off my ass and to the track more. But this has really got me down....where's the beer drinking smiley? But I woop soo much ass on the street it's hilarious, I just don't get it.
I have no idea what DA means, I wanted to ask the techs what it was but didn't wanna look like a dumbass. I can check the elevation. I'm sure it's close to sea level as I'm in gulfport close to the gulf.

PAY PAY PAY to have someone write you a tune... im serious. many guys on stock engines with MPI twins have ran in the 11's... obviously you have not logged your rail pressure... that could be a problem as well. I bet you have a professional tune your truck you will shave 1.3-1.5 seconds off your ET's and easily pick up 150hp or more. Hell I ran a best of 12.1 @ 113.9 on a 4094 modified single cp3...

 

[paint94979]

I have a CC/SB and I personally weight 220 lbs... my trucks total weight with a 1/2 tank is 6740... I have the tailgate and spare tire pulled. thats it my seats are all in place. Your wheel/tire combination is also probably very heavy.

 

[wikdlmm]

I run my 2wd with slicks an cut 1.8 60ft, at 104 mph. Fastest for me was a 13.12 an I'm at 1700 ft above sea level so that should give you something to base off of.. I have efi, tranny, and lift pump on stock charger'

 

[paint94979]

if you go from a 1.89 60' to a 1.68' that is .2 right there... plus the addition of .3-.4 ET reduction from putting your truck on a diet that is over half a second right there.