I was out at ATCO racway in Jersey this past weekend and 3rd gear wasn't pulling as hard as it used to....besides bogging and spinning tires...i sucked this weekend...i was running times i ran N/A....need some input....here's a list of engine mods:
Gm Charger
2.7 pulley
Vortech FMU
Walbro 255 fuel pump
Denso Iridium plgs
Ground wires
Pacestter Headers
Custon 2.5" pipping
Catco High Flow Cat
Vibrant Carbon Fiber muffler
could be traction issues....prob alot less becasue of the upgraded pully
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15.6727@86.7124 at capitol raceway
Since you have a smaller pulley, you should get a scan tool.
To see if you are getting knock retard. The scurge of any non intercooled eaton blower.
If the computer senses knock...it retards your timing. It gives the timing back in steps...listening for more knock each time...gives a little more back...listens for knock...and so on. That's why I will not put a smaller pulley on my car. Unless I intercool.
the temps outside were around45-50 and with windchill..cooler than that...i wanna cold air the intake...will that help??
Craig Lewis wrote:Since you have a smaller pulley, you should get a scan tool.
To see if you are getting knock retard. The scurge of any non intercooled eaton blower.
If the computer senses knock...it retards your timing. It gives the timing back in steps...listening for more knock each time...gives a little more back...listens for knock...and so on. That's why I will not put a smaller pulley on my car. Unless I intercool.
to add to what he said go to this site.. its the same knock gauge i have and it is for the Jbodies, grand ams and, GTPs. Also if your making any thing over 6psi, i can tell you already you are getting knock and it is backing down on the timing... you will need to get alcohol or water injection to get over that limit. And i have the dyno proof to prove this. (with a header, and 6psi pulley the dyno was 201hp at the wheels and with the 8psi pulley it was 203hp at the wheels)
Knock Gauge
Thanx for the info guys...much appreciated....how is the knock gauge working for you??
Guys,
You're missing the obvious one. You said these are your only engine mods:
Gm Charger
2.7 pulley
Vortech FMU
Walbro 255 fuel pump
Denso Iridium plgs
Ground wires
Pacestter Headers
Custon 2.5" pipping
Catco High Flow Cat
Vibrant Carbon Fiber muffler
Your profile says the following:
Ractive Warm Air Intake
Top Fuel Underdrive Crank Pulley(Took off)
AEM Underdrive Alt Pulley(took off)
Denso Iridium plugs
Red Ground Wire kit
Optima Yellow Top Battery
JetChip Comp Module (took off)
Catco Cat
Custom 2.5" piping
Vibrant Carbon Fiber/Titanium exhaust
GM Supercharger
Pacesetter Headers
Vortech FMU
Walbro 255 LPH Fuel Pump
Casper O2 Simulator
Zex Dry Nitrous (Not installed)
SPEC Stage III clutch
Upper and Lower Engine mounts
Autometer Lunar Boost and EGT Gauges
I'm going out on a limb here but is this a list of partially what you have already along with being a wish list? If so I suggest you change that clutch out for the SPEC you want. Then again, you have stuff on here saying "Not installed" and "took off". Could you verify whether or not you have the clutch installed? I think that's your culprit if you don't. It was definitely mine up until this past weekend...
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i wasn't counting the clutch as an engine mod...but i did forget to mention the O2 simulator in my list...i have all of these on my list what's on and not on.....
Clutch grabs great...had to learn to drive all over again..but it's in there
Thanks for the correction. The next logical step would be to cool the s/c due to the fact that the 2.7" causes way more heat to build up.
Get that nitrous on and start spraying a 25 shot. Since you have a Walbro pump, your car should be able to handle the pulley and nitrous just fine.
Then again, you might want to start setting aside money to invest in some fuel management. Greddy E-Manage all the way baby!
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I've also got the VOrtech FMU on there...i jknow i don't need it since i have the reflash...but i wanted the extra fuel in there for the nitrous.....or should i just bump the FMU??
Just my opinion but... If your running the Reflash AND a FMU you are dumping way to much fuel in.
Go put it on a dyno with a wide band sensor and I'll bet your in the 10 - 11 to 1 ratio or richer. Not good for performance. All the Reflashed dyno runs I've seen even with the 2.7 pulley are in the 13 - 13.2 to 1 ratio.
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
My thoughts exactly. Chances are, you bogging the engine down pretty good with fuel. Leave it to me to not see that on your mod list
Sell the FMU and buy a fuel computer. Then take the car to a dyno with a wideband O2 and do some tuning.
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I had it dyno'd b4 the full exhaust and 2.7 pulley...dyno'd at 170whp...10 less than my orignal dyno without the FMU......but the dyno with the FMU show's a 11.9-12.1 A/F all the way to fuel cutoff.....i only want the FMU on there for when i add nitrous.....i know i make more power leaner....but i wanted to avoid being in the 13+ A/F ratio....or should i take the FMU out and still add the nitrous (35-40 shot) w/o worries??
you guys are making it sound like the 2.7 Pulley is a bad idea. Everyone before said it worked great, didnt detonate, and was perfectly fine for A/F ratio.. .
2006 Black Cobalt SS Supercharged G85
13.91@102.77
it's probably my FMU adding too much fuel that's reducing my HPs...i'm gonna run it with the nitrous installed and then run the nitrous again without the FMU to see the difference...i saw over 7lbs one day so it's great...just gotta dial the car in right so i can make use of the extra boost
Blackwidow wrote:i was running times i ran N/A...
Same here, sucked. Only times I ran decent was after the car sat with a bag of ice on the charger and the cooling fan on for 20+ minutes, hillbilly intercooling. I ran a 15.0, then went and ran right after that, and ran a 15.7. Heat>charger
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dude your running to rich, its not a heat issue with the 2.7 when you go to a 2.6 then it becomes a problem, the charger will run really hot an bog the car down when the car runs rich trust me i know from experience
Since your running so rich,you probably plugged up your cat.Id get that checked out first.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
I'm running rich in preperation for the nitrous....but you're saying the my running really rich is what cut my power down right??
yup thats what happens, your car will run hot and like crap with a rich condition, i was running rich when i first put in my injectors and i didn't realize that my calculations where off and i was running very rich so i turned it down the pressure to the correct one it should be at and it runs awesome now
do you have the gm reflash? if so your reflash should take care of the 2.7 pulley no problem and can even take care of the anything up to 2 bars but the problem with the supercharger is the heat but thats only when you stick on a 2.6 because to be honest i think the 2.7 is perfect for it
if you plan to go to the track then i can see how someone would want to use the 2.6 but i would only do that with a small shot of n2o to cool the charger to actually be able to benefit from it being on there, not only that but you will also get the extra hp from the shot as well
for everyday driving stick with the 2.7 but please shut off/ take off that fmu it isn't needed right now and its messing with your powering and might also be harming your engine
Sweet...thanx for the info guys...My car is actually in storage right now cuz i'm goin on deployment....but as soon as i get back, i'm installing the Zex kit I have....
ORANGE Z...will the walbro pump be enuff to support the 2.7 pulley and 35-40 shot of ZEX without me running lean?? I was told that the A/F ratio of 11.9-12.1 that i'm in currently with the FMU installed is optimum for a roots-type charger.
yes the walbro is more then enough
Blackwidow wrote:Thanx for the info guys...much appreciated....how is the knock gauge working for you??
It is working out nicely... i personaly would never drive a boosted car with out it... knock is what will kill your engine off so there for when you see it creep up into the yellow its best to be letting of the gas or turn the car off...
remove FMU and replace the cat and add nitrous.
