Ok guys. to start off, new to the forum. I was directed over here from G35driver to get some better help. i have an 04 5AT sedan. bone stock at the moment. the motor blew about a month and a half ago at 132K (oiling issues causing spun bearings and a plethora of other issues. new motor is coming out of an 03 G and has 70K. Turbo will be a GT3788. specs are (compressor side) 62mm inducer, 88mm exducer. .58AR.....(turbine side) 72.5mm turbine. 78 trim. and .90AR. im looking to run 8-9 psi and be up close to 400WHP. im planning on either 410cc or 440cc injectors and an aeromotive fuel pressure regulator with a return line. i havnt decided on a mid mount turbo or going through SFR to get the pre turbo exhaust piping to put the turbo where the factory airbox is. as for questions, with the return line and bigger injectors is that going to be enough on the fuel system or do i need to do an in tank pump. are there any big forseeable issues with the factory driveline? is there going to be a big advantage to me doing the top mount turbo over the mid mount. i know the top mount should spool a little quicker but any huge differences for usable power.
right now build list is,
turbo exhaust work
turbo
intercooler and piping
injectors
fuel pressure regulator
return line
wastegate
blow off
custom made intake

is there anything im missing? any help or insight would be greatly apreciated guys

 

I would look into a new fuel pump…a walbro is $100 and you know you're covered. I don't know the capacity of the OEM fuel pump, but Im sure someone will know.

The drive shaft will take 700whp, it's a carbon fiber composite and as long as you don't have any damage (knicks or missing chucks) you should be ok. The axles are in that neighborhood too…

I like the front mounted with modification to add airflow bc that **** gets hot! Since your block is out, I'd wrap your headers/cats/exhaust with heat-sheild.

You didnt mention anything about cooling system modifications nor an oil cooler…I would consider both...

 

Just to correct you on this...the mid mount has less exhaust piping (length) between the headers and the turbo flange than a top mount kit. So, in theory it is the other way around when it comes to spool.

 

+1 oil cooler.

edit : didnt realize he was auto

 

Only the Z has a composite driveshaft. OP has a G sedan.

OP,
If you intend to go for 400whp with a single turbo setup, you will need to upgrade your auto trans. A stock 5AT won't hold long at that power level.

 

Blew the engine while N/A, Scribed before turbo build and new blown "blown" motor.

 

400 seems to be the agreed upon Max... But with adequate cooling- deep pan, good large cooler... As long as he's not wailing on it all day he should be okay. I guess a big part of the longevity is the condition it's in right now... And to find out you need to open it up- and if you're going to open it up you might as well upgrade it (packs) lol.

 

Correction on this: top mount has less air flow since it's packed under the hood with little airflow. Tucked up next to the engine and radiator the top mount turbo systems on these cars will be more hot than any midmount with ample airflow.

Did you get this turbo cheap or have it left over? gt35r would provide better spool and power curve for a stock block 400hp.

You will need a walbro 255 at minimum for fuel.

 

I disagree with such blanket statements that don't take into consideration what FI setup is being used. Most Vortech SC guys seem to do OK for a while with what you stated. However, the torque level and delivery is quite different with a turbo setup, especially a T3 single turbo setup. Most turbo guys don't last long at 400whp on a bone stock 5AT unless they drive it like a b!tch.

With a T3 turbo at 400whp he would likely be making as much or more peak torque, depending on his exhaust setup. There was a local PL customer here in AZ with a 5AT who started slipping at 350whp within only a few months. He was interested in buying my fully built trans, but didn't have the money. Like most 5AT guys who pull the trigger on going FI, he didn't fully research or plan ahead and budget for upgrading the trans.

 

That's not entirely true either since most of the top mount ST kits route the intake and air filter outside of the engine bay and in front of the radiator, near the front grill.

 

He's refering to the turbo itself and the heat it will generate not the intake air =p

 

No, he said it would have less air flow. I don't think that is true.

 

exactly

There is far less airflow around the turbo in the engine bay than one sitting under the car. So yes, the turbo will run hotter under the engine bay.

 

OK, now I understand what you are saying. Regardless, I think perceived issues or problems with heat soak get grossly overstated on the VQ platform versus other platforms that commonly run top mount turbo kits.

 

so in tank 255 it is. sounding like the turbo under the car right behind the motor under the car will be the way to go. as far as the tranny im not too worried cause it wont constantly see the abuse. its a daily so it will likely normally be on a very low boost tune unless im going out to have fun. also does anyone know if the lsd from a 350 or a g35 s will just drop right into my rear end?

 

That's what they all say at first... until they are actually boosted and their trans starts slipping. I've heard it a hundred times before. A few of those guys ended up asking me how much I wanted to sell my fully built trans for, but could only afford about half of my asking price because they were strapped for cash after they went FI and didn't plan or budget for trans issues. At the very least, I highly recommend you get a TransGo valvebody upgrade and a decent sized trans cooler.

P.S. The diff in the Z and G are the same. The VLSD is an easy swap.

 

Quaife may be different but I needed a quaife from a 350z mt- so I suspect you'd be similarly limited. Be careful what you buy! Might be different with the sedan - but worth double checking before you buy.

 

i know the z and g diffs are the same. but do i need to get the whole thing out of an lsd car. or just the guts and swap out.

 

Yes, they're the same inside- but the way they're mounted needs to be looked at closely. We originally got the LSD for what would be the 350AT... natural choice given that I'm an AT coupe... right?

Wrong.

Anyway- I'm just saying to make sure.

I also noticed you never mentioned to anyone here that you were hoping to keep this all under 3k... or has that budget changed since you posted elsewhere?

 

G and Z diffs are identical, it's far easier to swap an entire VLSD pumpkin out vs swapping the guts. The non VSLD have different axle stubs though. Usually they are fairly easy to find a pumpkin in the classifieds or local auto wrecker.