i was wondering if anyone knew what size throttle body we have on the 05 LS2? i was looking on the pontiac website, and it says for 06 they have a newly enlarged 90mm throttle body? yet the power stays at 400hp and 400 ft/lbs. if this is a 90mm, then i think an aftermarket one would be useless (for 06) and us 05 guys and just go buy one from GM, ifs its not horribly expensive.
no, i dont plan on this being my first upgrade, but after i buy a few other things (new intake, complete exhaust), why not help the motor suck more air in?

Remember the 05-06's are a "Drive by Wire" system. There is no old fashioned throttle cable. Therefore the 05/06 throttle bodies will be different than all those aftermarket TB's designed for the "old" cable operated systems.

Plus I was under the impression that the 05's also had the 90mm TB already. Let me do a little background check and get back to you on that one unless someone else can confirm it beforehand.

Plus unless you have some serious mods done the stock TB is well prepared to handle air flow. I have heard some people claim it won't be a restriction until 500 REAR Wheel HP. Save your money for another mod that will yield you greater performance gains. :)

yea, i know the LS2s have ECT, and i know BBK makes some electronic throttle for the gen-3 motor in some of the trucks. and im sure companies like them and FAST might make some later, but if they arent 90mm then they would be pointless.

also, i didnt know that about the stock one being able to handle 500 wheel hp. thats probably more than i will ever put down to the wheels. i would like to force feed the motor, but without building up the bottom end, i wouldnt be able to run that much pressure.

I just looked it up in the 05 Brochure.

90 mm TB for 05's

04's have a 76 mm TB

I have heard several people on this site and other sites claim that the stock TB and intake will not be a major restriction to building power up to 500 rwhp.

Again I'll defer to our more tech savvy members for a more detailed explanation. I guess it also depends on your goals for your engine too. Personally I'd say don't worry about it yet. :)

the throttle body is very decent for that car, but my cousin who has beena chevy mechanic for a long time can say that the air flow sensor on the LS2 holds back a lot of power, look on google for mass air flow sensors from gheradalli something like that. these guys are the leading aftermarket company for better mass air flow sensors, they have for both Ls1, 2, and 6 and a couple of extra goods as well.

its granatelli (if were thinking of the same one). they make some pretty good ones, and with the screen on it, still out flow the stock ones. i think without the screen is too much unless youve got some major work done.

defintly worth it, yea your right thats the company im talking about, defintly worth it if you also buy slp performance custom air intake hood scoop for the car that also functions well and straight into the throttle body

I have the Granatelli MAF for my 05 GTO. They cut out a lot of the center plastic piece that runs through the diameter of the housing and recalibrate the MAF. Don't take the mesh out unless you want problems. I'm happy with this MAF. Mine is calibrated for a CAI which I also have. I wouldn't bother buying a MAF if you don't want to spend the money to get a CAI.

thats kinda what i was thinking to do... buy a K&N intake, getting the granatelli maf for cold air intakes, and then doing the IAT relocation onto the box for the intake. i dont want to cut the wires to do that, but if i have to, oh well

Granatelli MAFs are junk. I can't believe they still sucker people into buying them. After the car learns the a/fs again, don't be surprised if you lose 2 tenths at the track. The A4 cars will have trans problems because the line pressure vs. MAF algorithm in the PCM is skewed the wrong way with the crapatelli MAF. Stick to a descreened stocker if you really must modify your MAF, you really don't need to do anything else with it, as it is good well into the 10s descreened, or 550 RWHP for you dyno racers.

Granatelli MAFs are junk. I can't believe they still sucker people into buying them. After the car learns the a/fs again, don't be surprised if you lose 2 tenths at the track. The A4 cars will have trans problems because the line pressure vs. MAF algorithm in the PCM is skewed the wrong way with the crapatelli MAF. Stick to a descreened stocker if you really must modify your MAF, you really don't need to do anything else with it, as it is good well into the 10s descreened, or 550 RWHP for you dyno racers.

I was suckered into buying one. I've had it on my 05 A4 for about 6000 miles. No shift problems. Taking the screen out will cause some problems with the MAF readings.

I was suckered into buying one. I've had it on my 05 A4 for about 6000 miles. No shift problems. Taking the screen out will cause some problems with the MAF readings.

Your trans may shift fine now, but in the long term your trans will suffer. You aren't making any real power, so it will obviously take longer than in a heads/cam or full bolt-on car, but it will happen. I've seen it happen far too often on customers' cars. The MAF screen delete will not cause problems with the MAF readings, but a granatelli MAF will.

I don't doubt that you've seen it happen on other cars. Is there a way to know for sure what affect it is having on the trans other than waiting? Any diag tools?

The PCM calculates engine load via airflow reading in hertz, throttle position and several other values. If the airflow parameter is below a certain threshold, the PCM does not allow enough transmission line pressure since it doesn't "realize" that the airflow reading is different from the stock unit. The way the GMS MAF works is by leaning the car out slightly, since the factory tune is on the rich side. It accomplishes this by delivering a signal to the PCM which shows less airflow than actual, which causes the PCM to add less fuel. It was a good idea in theory, but in practical application the unit does not live up to expectations. The transmission line pressure issue is an unfortunate side effect. After the PCM re-learns the air/fuel ratios any benefit is removed from installing the aftermarket MAF at all, but the detrimental effects of the installation of the component remain. Another issue is the calibration of the aftermarket units, the output is not delivered in a smooth linear fashion as the signal from the stock MAF is. All of this has been observed by reading through the stock PCM tables, datalogging via AutoTap and a Tech2 scantool. I have also plotted the MAf output from several stock and aftermarket MAFs using a Tektronix oscilloscope. Hope this provides enough information for you.