disappointing track times

02denali · May 10, 2003

i have the listed mods and i am disappointed. i believe it should run better. in first it did good. in second it did good. when it shifted to third it fell on its face.

60-2.45

1000-13.73

1/4-16.34 1st run

60-2.43

1000.13.86

1/4-16.34

any suggestions. besides torque converter. going to try a gear next but i still am trying to find why it falls on its face in third. ???

MarkD · May 11, 2003

The following is an educated guess (from many years of modding cars and trucks) of the gains you should see in a 4k lb truck.

Let's run down the power mods you have...

2002 silverado

goodmark cowl hood

-good for maybe 5-10 fwhp

american racing 20's-goodyear

-look great, but heavy, probably take 10-15 hp more to turn

2 1/2 inch custom exhaust with dynomax bullets

-definate improvement in backpressure- 10 hp, even trade on weight

jba headers

-good improvement, maybe 15 hp

granatelli mass air

-probably no change with no other mods, factory MAF is not a problem at factory air flow levels

k&n fipk

-good mod, 10 hp

hayden electric fans

-probably best mod 10-15 hp

thermostat mod

-+ .2 hp

tb mod

-+.3 hp

msd plug wires

-not a bad idea, but probably no perf. gain.

Where does that leave us...

+5 to +10

-10 to -15

+10 to +10

+15 to +15

- to -

+10 to +10

+10 to +15

+.2 to +.2

+.3 to +.3

__

40.5 hp to +45.5 hp at flywheel

* .8= 32.4 rwhp to 36.4 rwhp gain

as a guess, you should pick up 2 to 3 tenths in the 1/4 for those gains.

canadianchevy33 · May 12, 2003

It should run much faster then that. Some ppl have stock 5.3 running 15's. I think it might be your gearing saying you start with a 3.42 adding 20 inch rims would surely lower that to 3.0 or worse.

02denali · May 20, 2003

markd----man that is about the best answer i have had yet. it is perfectly true. and i am sure that some peoples times arent exact. i am going to put it on a portable dyno in a couple of weeks and see exactly what it is putting out. and hey thanks for the advice. if i have anymore questions i will ask you if you dont mind. thank you very muchoh yay i installed a new factory mass air and i am running consistant 16.21.that was with approx 300pounds of tools and stuff in the bed.

Blue Ghost · May 24, 2003

I know for a fact 20" wheels will kill your performance on any vehicle, not only will it kill your gearing, you have to stop and think how much weight you are adding at each wheel, each 20" wheel weighs approx. 34lbs, and factory weighs approx. 20lbs, that is a major amount of weight to get moving on take off over stock.

My truck has 4:10's and came stock with 245's and it hauled ass, then I switched to 18" wheels and noticed a major performance loss.

Good looks=performance death

my02denali · May 24, 2003

yay i am going to go to 4.10's i believe. my buddy went to 3.73's and is going to let me know how it turns out.

Cyclic · May 29, 2003

I run 15.7 on the following..................

2002 GMC SLE Extended Cab

5.3 liter automatic

3.73 with G80 (almost locker)

**Non-Supporting Vendor** intake

factory pipes with Flowmaster 70 series muffler

adjusted shift points (no tuning)

factory tires on a 3 inch lift (255/70R16)

With a 100 wet shot of nitrous oxide I'm at a 14.28 so far.

Plans for the future include a torque converter, dyno tuning, better tires, traction bars, and upping the nitrous to 150.

my02denali · May 29, 2003

HEY CYCLIC HOW DID YOU ADJUST YOUR SHIFT POINTS

Cyclic · May 30, 2003

I have a Preditor programmer but have not installed the tuning yet. I'm waiting for some dyno time so I can adjust the air fuel ratio. I probably won't go with the tuning because I don't want to run that high of fuel grade. I will adjust timing and air fuel on the dyno to optimize what I currently have. Right now by the tail pipe color I'm running pretty rich but the wide band O2 will let me know exact numbers.

Basically I have it shifting around 5600 rpm when under full throttle.

Ridinghigh · June 2, 2003

I got a 66 GMC 3/4 Ton Truck with a 350 in it. I run mid 14's.

Got a 600cfm Edelbrock Carb. Torker 1 Intake. Headers, 2.5" exhaust with 40 Flowmaster. Um. Thats about it. Going to electric fan and smaller more streetable tires soon. Right now I have offroad like tires. Oh I also have limited slip 4.11.

I am not too familiar with the new trucks but best of luck to ya Cyclic with gettin that beast goin quicker.

BigGreen · June 3, 2003

Those times are nearly exactly identical to what my completely stock 2001 Silverado extended cab, 5.3 L 2wd truck ran. Is your's and extended cab also?

Cyclic · June 3, 2003

Extended cab, no weight reduction, tool box, towing package, complete stereo system with sub woofer. Not to mention my fat but.

Right now my biggest limiting factor is the factory torque converter. I have zero wheel spin off the line but more than enough power to chirp the tires when it shifts to second. After adding the torque converter I know I will have to get better tires to hold the power. I should be well into the thirteens before I even up the nitrous ammount.

Hopefully within the next couple of weeks I can get my air/fuel ratio adjusted correctly on a dyno. As I said its running really rich right now which is why I havent upped the nitrous yet. Just playing it somewhat safe for now. On the dyno I will adjust the normal A/F and then the nitrous A/F ratio. It should help alot also even without the torque converter.