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Throttle body



If youre N/A and staying that way Northstar would be too big.Id say just get your stock one ported 3-5mms and you should be good.
 
Will there be much benefit with the northstar if I supercharged my gp or can I stick with porting my OEM and still supercharge it later?
 
Get a tb from a s/ced car

Normally aspirated tb from zzperformance:
stock 65mm bored out to 68mm

Supercharged tb from zzperformance:
stock 69mm bored out to 72mm

Some epoxy work on the back side of the t/b may be required to fill the holes on the supercharged t/b to seal properly, but if you plan on going s/ced in the future you might as well start off with the larger bore t/b, and port it if you wish.

Even if you dont port out the t/b of the supercharger you have a larger opening than the ported n/a t/b.
 
porting the TB blade isn't what you should be concerned with.

its the MAF hump thats the issue.

remove the hump and have your car tuned.
 


Go to zzperformance website under:
-air intake and fuel delivery
The images for the ported maf sensor is shown with the ported tb's

Do a search for the following on there site:
Pontiac GTP High Velocity Throttle Body Info

You will link to an article with images of the newer maf hump and older maf splitter, they only stage 2 port the newer maf hump although others have done both. This will require the computer be tuned fot the larger area around the mass air flow meter. (zzp suggests this for 12 second 1/4 mile cars)

I would suggest seing if a supercharged tb from the same era 97-98 or 99-03 has the same opening around the mass air sensor, negating the need for a tune, allowing you the benefit from the ported t/b blade.
 
98gtp said:
I would suggest seing if a supercharged tb from the same era 97-98 or 99-03 has the same opening around the mass air sensor, negating the need for a tune, allowing you the benefit from the ported t/b blade.
Click to expand...


GT Throttle body= .021 grams a sec of air
GTP TB=.024 grams a sec of air. Tune will be needed
 
Well since this is the N/A section I'm assuming your in need of more air since you have a laundry list of mods?

Larger TB would be needed for a Cam/Heads/Header/HV3 setup...At the point of a cam/headers alone I'd have the stocker ported...I don't think ANY N/A guy would be needing a Northstar...a ported L67 would suffice PLENTY of air for any non-boosted car. But, IMO....unless you have a cam or rockers...and headers...or even a HV3 and or headwork...then your in no need of a larger TB. If you don't have any mods...maybe I suggest Speed Daddy headers, with some form of an air intake (whichever you may prefer but Fenderwell's seem to work better on N/A apps), an HV3 Upper Insert, with ZZP ER Rocker Arms or one of their cams...either a GT1 or GT2...
 


Just wondering but it looks to me that its clogging up the air way. Clogged air way = less throttle response? My uncle who has worked as a GM mechanic for 30+ years says its an unneeded part and to leave it out to increase air flow, but he says MPG may drop a bit? But i will see better throttle response so idk.

Thought this would be a nice thing to chat about :D
 
it does not need to be removed EVER. it makes it so there is laminar flow across the MAF. tell your uncle he doesnt know anythign about MAF cars and should stick with carburators.

it is not a flow restriction. just leave it alone.
 


I thought the Powerlog manifold was poorly casted so id like to replace it please help me find one i've done so much googling with out any luck :(
 
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