Thread: Injectors

I'm looking at upgrading my injectors and fuel pump.

I can't seem to find a replacement pump recommended for the 3800 series II.

I did however find this link:
http://home.mchsi.com/~d.traub/fuel.htm

I'm upgradin the MAFS, as well as the cold air intake to accomodate the increase in boost I anticipate. And it appears I'm going to go ahead and do the pulley drop to a 3.2". These changes so far as my research has gone will give me the air I need to handle the larger injectors.. I just need to upgrade my fuel pump for the higher RPM range.

If I'm in error with any of this, please do let me know. I'm still a learning ignorant at this point, and any advice would be appreciated.

As per the safely modding thread, I've already replaced

belts, thermostat (180), plugs (cold plat), wires, checked the intake gasket. Mechanic swears it's aluminum and in good shape.

replaced the fuel filter, and transmission filter. replaced Tranny fluid w/ straight Dexron VI, and the supercharger fluid as well.

I couldn't find any headers, speed daddy or not.. I've pretty much decided I'll get a custom exhaust to do a little straightening and drop to a 3" after the down pipe.

I'll start there, if I need more room to breathe later I'll address it then.

Someone tell me I'm not screwing up here, or if I need to take certain precautions. Advice and / or criticism is welcome.

Thanks in advance!


2004 Grand Prix GTP w/ 81k miles.

Try a search on here for Racetronix fuel pump. prjperformance.com has a drop-in solution, and I would recommend the rewire with the pump.

Ottperformance.com has some very good prices on injectors. You can go pretty far on 42# injectors with gas, but if you ever think you might want to run e85, go with 65# injectors. I'm guessing you have some way to change the IFR table for larger injectors, or are going to get a custom tune.

Edit: I just realized you have a 2004. I don't think the Racetronix kit will work as a direct replacement, but I think others have modified it to work. Hopefully, someone with a later year can add some info.

Also, do you have some way to scan when making these changes?

Right...can't do anything there...'04 is a returnless fuel system and has an in tank filter too.

What I don't understand...is your trying to upgrade the fuel system and you have no reason to. Only thing I could think of there is going to convert it to E85. There...you will need 60lb. injectors, a new filter, and a damn good tune. If your going to start throwing stuff at it do things that need replacing now...like the exhaust system...get the Speed Daddy headers (and yes, any 97-03 headers will fit an '04+ car too). And also...to continue form your other thread...go buy autolite 606's, gap them at .055" and buy a spectre cone filter (autozone) and yank out the stock air box and bolt the filter to the end of the MAF. Done.

Well put ^^^^

Research more. noway can you run a 3.2 pulley on your car with what mods you want to put on there. You dont need to upgrade your maf. You will not be close to maxing it. Speed daddy headers will fit your car FWIW

Originally Posted by 01gpgt01

Research more. noway can you run a 3.2 pulley on your car with what mods you want to put on there. You dont need to upgrade your maf. You will not be close to maxing it. Speed daddy headers will fit your car FWIW

This.

I can't find any speed daddy headers to save my life...

I have a shop wanting to do a custom exhaust. I was holding that off until I could find a set of decent headers.

My thought process was to increase the air flow and boost to accomodate the faster pumping injectors. I was looking for a fuel pump under the impression that higher rpm's lower voltage would slow the flow.

I'm not dropping the pulley until I have all the parts. I have a race shop here that'll tune the car after I install all the parts.

I was shooting for doing it all at once.
MAFS/Air intake
Injectors
3.2 pulley

I'd like to swap the headers, and straighten the exhaust at the same time.. still having troubles finding a set that are "affordable" and reputable. Speed daddy headers don't seem to exist anymore.. not even on Ebay.

The filter for my fuel was midline down the chassis, not in the fuel tank oddly enough... Does that mean it might have been an earlier model 04? Was there significant changes in the later 04's ?

The plugs I used were recommended by the local GM dealership as direct OEM replacement of the ones I removed. The ones I took out were plat's as well...

As far as I know.. that was the first time they've ever been changed since the manufacture.

Please let the comments flow. Any and all advice is welcome.

You read my Safely Modding thread yet? You do know that to run a 3.2" pulley on a GenV car you need at LEAST a cam or an intercooler AND headers.

Originally Posted by bluegtp91

You read my Safely Modding thread yet? You do know that to run a 3.2" pulley on a GenV car you need at LEAST a cam or an intercooler AND headers.

x2. Don't touch the pulley until you max out timing on the stock pulley and prove that you can run KR free on that. Scan in many different conditions, don't just run one scan and think you are safe. If you run KR free with max timing, it would be safer to first drop to a 3.4 and scan again. If you get KR under certain conditions, then you can drop timing to keep it safe.

If you go right to a 3.2, you will have to drop a bunch of timing, and you will have no power.

Only thing you'll get...is more whine. Which is stupid considering a stock car will hand your car its ass.

Originally Posted by BlackGS

x2. Don't touch the pulley until you max out timing on the stock pulley and prove that you can run KR free on that. Scan in many different conditions, don't just run one scan and think you are safe. If you run KR free with max timing, it would be safer to first drop to a 3.4 and scan again. If you get KR under certain conditions, then you can drop timing to keep it safe.

If you go right to a 3.2, you will have to drop a bunch of timing, and you will have no power.

Got it!