Help me boost my 3400

[Bridgetown]

The GT3076R has different turbine housing options (4 bolt & v-band) in A/R's of 1.06/.82/.63 What do you think would be the best option?

[robertisaar]

well, .63 would likely get you boost before 3000, and 1.06 probably wouldn't until at least 4000.... i would go with .82, but that's a decision of preference. you can have it spool early and start to choke up top, or have the boost threshold higher(not lag like most people like to think) and make better peak numbers, or you can have a mix of both...

[Bridgetown]

That's kinda what I was thinking. Any advantage to v-band vs. 4 bolt outlets? I found a GT3076R with 38mm wastegate combo for $1700 includeing 1 yr. warranty & worldwide shipping. Is that a decent price?

[Bridgetown]

Has anyone got a good source for Garrett turbos?

[Bridgetown]

Would the TGP chip in my '7730 be a good place to start for tunning from?

[FerrariFan]

I realize you are looking to hear what others with your engine have done but sometimes it's best to do your own homework first so you can tell if something someone is saying doesn't add up. That being said I found this. Looks like someone out there with a 3400 has done a lot of the homework for you.

http://www.jeepnuts.com/12sGASE/turbo.htm

he used the tables from here.

http://www.turbofast.com.au/turbomap.html

I think the TGP would be a good starting point since it's already set up for a turbo and DIS, however it is ODBI and it uses a 2 bar MAP and not MAF.

$1700 seems a bit high, even with the wastegate. Check this out.

http://www.google.com/products?q=GT3076R&rls=com.microsoft:en-us:IE-SearchBox&oe=UTF-8&rlz=1I7RNTN_en&um=1&ie=UTF-8&ei=KuRDTK7CCIL58AaMsZUh&sa=X&oi=mode_link&ct=mode&ved=0CB0Q_AU

[Bridgetown]

Don't worry this isn't my first rodeo. I swapped the complete 2002 3400 into my '86 Fiero and converted it to OBD1. I'm not a noob, just don't have much boost experience. It really pisses me off when guys jump down your throat for useing forums to ask questions. People have to start somewhere. That being said, thanks for actually posting some usefull info, and not just telling me do "Do my own research"

[Bridgetown]

I realize you are looking to hear what others with your engine have done but sometimes it's best to do your own homework first so you can tell if something someone is saying doesn't add up. That being said I found this. Looks like someone out there with a 3400 has done a lot of the homework for you.
http://www.jeepnuts.com/12sGASE/turbo.htm

Hmmmm... Found something in the link you posted that "doesn't add up"

"The GM LA1 engine is already pretty hefty as far as bottom-end components are concerned. It comes factory with a forged, internally-balanced crank and forged connecting rods."

[robertisaar]

the LA1 and every other gen 3 engine has forged rods(2 might as well, i wouldn't quote me on it though), but the crank is iron... the only 660s with forged cranks from the factory are certain non-VVT 3500s and the "high value" and "high feature" series(the VVT 3500 and 3900 are the HV, the new DOHC motors are the HF).

this is all IIRC.

but the 3400 crank WILL take abuse from a turbo. you'll find the transmission is going to be more of a problem than the bottom end is.

[Bridgetown]

I have a 5 speed Getrag which should handle 300hp, as long as I don't abuse it or drop it from 3000rpm. But, yeah, I think it will still be a weak link.

I have also heard conflicting opinions on the FPR on 3400's some say they are OK to boost on, others say no. What psi do the Trailblazer injectors run at? If it is higher then stock 55 psi 3400, I will need an adjustable FPR.
Also, running the TGP 2 bar map sensor should be good for 10 psi correct? That would be the max boost I would run. I would like to stay with OBD1 if I can, and do as little wiring as possible when I add the turbo system.

[Bridgetown]

One thing I don't see many pics of is the oil supply feed/return lines when boosting 3400's. Anyone got any pics of how they plumbed their lines? Also, if I do use a watercooled turbo where would be the best place to tap into the stock system?

[robertisaar]

IIRC, the trailblazer injectors go to something like 60PSI? that's not a problem, since it will be dealt with through the ECM when tuning. get me an exact year and engine and i'll see if i can pull the service specs. the FPR will be fine with boost... a 2BAR MAP should read to a second atmoshpere(14.7PSI), but i would shoot a little under that in case of an overboost situation and the sensor/ECM going nuts over it.

oil feed/supply: most people tap into the oil pressure sensor/sender housing, and then drain to the pan(haven't done this myself before, so i can't suggest anything here, other than asking more people, Schmieder(or is it ei?) did it recently for his 3100 GP).

water cooling: got a TB that uses coolant running through it? well, those lines can be repurposed to run your in and out lines for minimal modifications and maximum reliability.

[SappySE107]

Trailblazer are 28# at 62 psi. You can 3400 injectors at that PSI as well, and you can run the trailblazer at 43. They are 23.3# then. I would run larger injectors with a turbo. 36# at least.

[Bridgetown]

How do you calculate injector flow rates? Is there a calculation or online calculator. 3800sc injectors are 36# right? Do they swap into a 3400 fuel rail?

[SappySE107]

Yeah, they are 36 at 55psi. There are online calcs but you have to know BSFC, which is just a guess. I can see what dynomation says for fuel consumption and all that but I just guesstimate at 10x injector # rating. 28#, 280 hp. You don't want to go too large but going slightly over is better than going under.