supercharged question

peppersac · August 22, 2005

I just installed a powerdyne supercharger on my 02 sierra 5.3l and everything is running fine but at about 4500 rpm with full pedal my truck starts stuttering, but still accelerates good. Any one have any ideas?

REKIII · August 22, 2005

I just installed a powerdyne supercharger on my 02 sierra 5.3l and everything is running fine but at about 4500 rpm with full pedal my truck starts stuttering, but still accelerates good. Any one have any ideas?

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When turboing vehicles (the similarities between this and SC are obvious) I find that most RPM driven studdering probs are electrical. Most likely you hit the harmonic point of something at that RPM and it shakes violently causing a short or disconnect. Check all your wireing.

Or it could be a fuel map problem.

Bob

zippy · August 22, 2005

i'd say you're either experiencing a lean condition or have a spark issue. if you're still running the stock spark plugs you may also run into that issue. i'd recomend getting a wideband 02 run on it.

mudbug660 · August 22, 2005

I'd recommend a westers pcm or any of the other of the custom tuners. The hypertec might be causing this condition since it might not be programed for the supercharger.

peppersac · August 22, 2005

i have been tuned by pcmforless and have ac delco iridum spark plugs (new). what is a wideband run?

zippy · August 22, 2005

i wouldn't recomend those spark plugs for your application.

peppersac · August 22, 2005

why not??

AirForceAngler · August 23, 2005

Did you change to a higher octane fuel? It may be knocking or making a sound that the knock sensor is picking up and therefore retarding the timing.

Haulin' 8.1 · August 23, 2005

why not??

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The heat range is too hot for forced induction, they will likely induce detonation at WOT.

Vernon

peppersac · August 23, 2005

i am running a higher octane. which spark plugs do you suggest?

99Silver6.0 · August 23, 2005

NGK TR6 for the blower or N2O. Are you running the FMU?? if so, I think your not getting enough fuel at WOT and its choking. Time to get it on the dyno and have a wideband run. See what your air/fuel ratio is doing. LEAN IS BAD. Is it pinging?

peppersac · August 23, 2005

yes i am running a fmu. i put some octane booster in with my 91 octane and it all but cleared up. it was never pinging though. i guess i do need to go to the dyno.

99Silver6.0 · August 24, 2005

yes i am running a fmu. i put some octane booster in with my 91 octane and it all but cleared up. it was never pinging though. i guess i do need to go to the dyno.

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Those FMU's are a pain in the ballz to get set right. My advice to you is get some 8.1 or 8.1 marine injectors and ditch the FMU. That will help things out alot. That FMU is only there for one reason. To make up for low flowing injectors.

peppersac · August 24, 2005

Do you know where i could find those injectors at or how to tune my fmu? also would it be better to get bigger injectors or a diffrent fmu?

99Silver6.0 · August 25, 2005

Do you know where i could find those injectors at or how to tune my fmu? also would it be better to get bigger injectors or a diffrent fmu?

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8.1 marine injectors will be alot better idea especially on a blown truck at 42 lb/hr. I got my 8.1 31 lb/hr injectors off eBay new for $80 bucks. The injectors can be found on eBay, LS1Tech, SilveradoSS.com or on Arizona Speeds website. You do not want to use f-body or any other injector. If you try to the injector plugs have to be changed and the fuel rails shimmed up. 8.1 injectors are a straight swap deal. BUT, you have to get it tuned after that to get the flow rates corrected. The jump from a 24.7lb/hr injector to say a 31 or 42 is gonna make you run lean or not run at all. Who tuned your truck after you put the blower on?