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L36 To A L67

grandamle91

grandamle91

New member
My 98 GP GT bottom end went out and it doesn't have a supercharger and I wanted to know what it would take to drop a 3.8 with a supercharger on it.

Is there extra wiring mine doesn't have?
 


the boost bypass vavle and the 2 bar map sensor. you can get the wiring harness connectors from ZZP as a kit.
 
you need to have an L67 file in the PCM or it wont know what the hell is going on when you go into boost.
 


i just swapped you will also need the fuel pump and a fuel pump hot wire kit. the gts dont have a strong enough fueling system to support the l67 mine has been knocking like hell every since i put it in. i just ordered a 255 lph walbro pump and a fuel pump hot wire kit to get 13.5 volts to the pump. there are lots of hickups people just forget to mention so if you need any help pm me.
 
probably your best bet if you dont have the time and money to commit. I modded mine quit a bit when I put it it in but it is still not nearly as plug and play as everyone makes it sound. I am speaking from experiance.
 
thunder, you needlessly changed the fuel pump. the GT pump is just fine. i ran one down to a 3.2 pulley with no ill effects. my fuel pressure was solid.
 


Ok I sleeped on it and I've made up my mind, I want to swap, I'll just drive my Astro.

Can someone that has done this tell me what all I'm going to need\do.

When I go get the motor on Monday, I will be getting the whole motor, engine wiring, pcm, I'll be buying a new f/p

Anything else?
 
W Body Store

You dont need a fuel pump unless yours is going bad. You will also need an aftermarket tune because the transmission in the GT has 3.29 gears and the PCM is from a GTP with 2.93 gears.

Also any gaskets that you will need for replacing the engine.
 
My pump was just replaced. Do I still have to buy that kit you linked to if I'm going to be getting the whole wireing harness?

And besides programing the pcm for the trans i'm good to go
 
Actually thats my bad, you probably dont need that wiring kit. Im not going to say youre good to go because i dont know everything and i havent done it before. keep researching.
 


Well it sounds pretty straight forward since I'll have the org wireing\pcm from the supercharged GP.

we'll see what others say
 
you either need a gtp wiring harness or the wiring kit for your bbv valve and map sensor. The reason i changed my fuel pump is I was only getting 42 psi to the rail and mine was pulling 10 deg of knock at wot. i changed the filter fuel pressure regulator and went to a gtp pump which was apperantly weak as well and still got 42 with the key on engine off. If you need a tune call john at intense racing they do them for 170 with free unlimited upgrades it is by far the least expensive option out there and they answer the phone when you need help.
 
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