Want to Turbo my 3400, need help/opinions

[Niteflight]

I assume there is a adapter for the wiring harness? Is there any problem the different spray pattern will create? assuming that they are tuned properly.

[AaronGTR]

Ok long post here... There's no adapter. You have to cut the old plugs off then get new bosch style plugs with wire leads and solder them on. ZZ performance sells the bosch plugs in a kit, or you could get them from a dealer. Just have to make sure to solder the wires correctly (positive and negative).

Since that section of wiring harness is detachable you might just be able to buy a whole new one from GM or get one off a junkyard car. The '99 and earlier 3400's had bosch style injectors so get a harness off a pre-2000 car. Don't know if anyone's done this yet, but I'm assuming the main disconnect is the same (the big plug next to the alternator) and has the same pin locations. You might still have to change another sensor plug if they're not the same though, not sure. That harness also has leads for the cam sensor, MAP sensor, and coolant temp sensor. The cam sensor didn't change until like '03 I think, so they're probably all the same.

The difference in injectors is the nozzle style. The 22lb, 28lb, and 36lb injectors are all factory injectors and all pintle style. They have a fine spray pattern that atomizes fuel well at low rpm and when the engine's cold, so they tend to idle a bit better and get slightly better milage. The pintle can't open and close fast though so they start going stactic around 70-80% duty cycle. 42lb and 60lb injectors are disc type and they spray more of a stream pattern. They don't idle as well when cold or atomize as well at low rpm, but they get more fuel out at high rpm because they open and close faster so you can run them up to 80-90% duty cycle before they go static. They are better for higher rpm and WOT driving.

[Niteflight]

It would then just be easier to get bosch style harness' for the injectors and cut off the old delphi style ones and solder accordingly? thats all that would need to be done?

[AaronGTR]

It would then just be easier to get bosch style harness' for the injectors and cut off the old delphi style ones and solder accordingly? thats all that would need to be done?

Huh? Not sure what you mean.

You have two options. Take the harness you have a cut the injector plugs off (they are delphi) and solder on bosch style plugs, or get the harness from an earlier car that have the bosch style plugs on it already. You only need to do this though if you plan on using the 36lb GTP injectors or 42lb lucas injectors with bosch style clips. If you're using the 28lb trailblazer/envoy injectors they are delphi and your stock harness will work.

[Niteflight]

I think I may just get the GTP injectors then, 36ib should be fine at 9psi boost right? I want to leave a lot of head room just in case.

thanks.

[gectek]

thread about the ls6 springs, edit, make sure to use the PN SS 70816(its even on the box) instead of the 101816 that he posted

http://60degreev6.com/showthread.php?t=34256

[AaronGTR]

I think I may just get the GTP injectors then, 36ib should be fine at 9psi boost right? I want to leave a lot of head room just in case.

thanks.

Oh yeah, at 9psi 36lb injectors should be plenty, with room for a little more.

[Niteflight]

Excellent, thanks everyone this forum is very helpful.

I hope to get this project done and working by the end of march break, I just want to get a daily driver that is stable at 9psi that is my ultimate goal.

[MidnightriderZ24]

Oh yeah, at 9psi 36lb injectors should be plenty, with room for a little more.

at 9 psi my 28's were fine with room...

[Niteflight]

Another question about the ls1/6 springs, do I really need them? what do they actually help?

Can I run the engine turbo'd for a month or so until it warms up so I can take the engine apart and install the springs, or is it vital they be changed before hand?

[gectek]

well the springs are better for a more aggressive cam or for higher mileage cars, like mine with 174k mi on the clock, that exp valve float at the higher rpms, and i like the higher spring rate for quicker return and the possibility to use a bigger cam without worrying the only thing i would worry about is the pushrods, but thats another story

[AaronGTR]

You don't really need to change springs unless you are getting a bigger cam. In fact I don't recommend LS6 springs if you're staying with a stock cam... you don't need anything that stiff. If the engine has a lot of miles on it, switching to LS1 springs (or 3500 springs for that matter) might help to eliminate any possible valve float from spring fatigue. It can wait until you have time/space to do it though.

[Guest]

even if not running a larger cam, if you re going to boost, you need better springs. Period. They will not be able to follow the cam profile under boost.

Who here used stock springs under boost and started getting float as early as 4500 rpm?

You need something better though then stock.

[Niteflight]

Ok looks like I'll get the springs, and I may even get a cam later.

[grandprixgtp_91]

yes, and dont forget to use an intercooler. the guy that blew 2 motors , from his pics it looked like he had it plumbed right from the supercharger to the intake, thats a big uh oh for detonation.

Jake