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View Full Version : couple questions befor upping the boost a little



k20pwr
03-21-2010, 06:15 AM
Alright so nice weather has finally arrived and I am planning on upping the boost a little and get myself the 3.8 pulley. My question is would i benefit any (in a worth my while way) by getting a larger ID exhaust? I have the hks piping which is about 2.25-2.35 i think. I just figure if I'm gunna need a re-tune I may as well do it all at once. Any thoughts....?
Anyone got any #'s on what they gained from the 4.0 pulley to the 3.8? I'd like to be in the 240ish whp range but i don't know if that's possible. (currently 225)

other supporting mods
BCRH
Injen CAI
S2 stage 1 cams

Jpax
03-21-2010, 10:59 AM
changing exhaust will help but if your wanting to maximize the Hp potential then you should heat wrap the BCRH and or have it waynes coated, with a new 3" exhaust will yield you better results with the 3.8 pulley.
increasing the efficiency of your air pump will make your air pump put out a potentially higher number every time.

superchargedk20
03-21-2010, 01:12 PM
I dont see really much gain commin from u goin to the smaller pulley unless u have something to cool it. The 3.8 is gona run really fast and ur gona knock. So ur gona prolly have to get detuned and loose timing due to it. I hit 255whp on the 3.8 pulley but i also had to run water/meth so i can add more timing, also had corwer stage 2 cams BCRH and revvin the a3 to 8700 rpms. And no the a3 never blew at that high. U get the right tuner and they can work wonders ! I also was runnin the apexi n-1 which i think is only 60mm. So that prolly killed me
http://i212.photobucket.com/albums/cc65/superchargedk20/dynojet.jpg

k20pwr
03-22-2010, 05:44 AM
I dont see really much gain commin from u goin to the smaller pulley unless u have something to cool it. The 3.8 is gona run really fast and ur gona knock. So ur gona prolly have to get detuned and loose timing due to it. I hit 255whp on the 3.8 pulley but i also had to run water/meth so i can add more timing, also had corwer stage 2 cams BCRH and revvin the a3 to 8700 rpms. And no the a3 never blew at that high. U get the right tuner and they can work wonders ! I also was runnin the apexi n-1 which i think is only 60mm. So that prolly killed me
http://i212.photobucket.com/albums/cc65/superchargedk20/dynojet.jpg

Sounds like this isn't even worth my while to do the 3.8 pulley upgrade then? Any one else have any input? If i can make some gains i'de like to up the boost but if not i would hate to waste the money.

Gilmour
03-22-2010, 07:15 AM
Keep the 4 inch pulley, upgrade to a larger exhaust and upgrade to an A2 head. Your entire system would breath better and you'd gain vtec on the exhaust cam for a jump in power.

K20A EP3
03-25-2010, 06:51 PM
ive had my charger with the 3.8 on for like 2 months now, im loving it but ready for more lol!nwas thinking of watermeth

DirtyEP3
04-15-2010, 03:40 PM
I am using a 3.7 In pulley, and making 12.5psi when it started to break up on the dyno. i have some extras in the car tho. no water/meth yet either. make sure you have all the mods to support it, cuz it is a pain in the ass to have to go back and do something twice. If you have a good tuner you should be happy wit the results. a bigger exhaust will be helpful, plus the header wrap. but don't for get the intake side also! Larger TB, Inlet Elbow, Etc.....

vbpracer
04-15-2010, 07:22 PM
Honestly I really don't see the need for a 3" exhaust, for your setup 2.5" is plenty.