Got Bored... Turbo Time!!

[Cable]

Hey guys, most of you veterans already know I own a '75 Datsun Z powered by a 2005 LQ4, mild Lunati Voodoo cam 60511 (.567/.567", 222/228 dur, 113 LSA), Comp pushrods, and LS6 valve springs. I am also running a stock LS1 intake manifold, Bosch 42# 'Green Top' injectors, and a Walbro 255 pump in the tank. The TB is the stock DBW unit for the LQ4. Everything is tuned with HP Tuners software (I own) using a wideband O2 input. I am also running a 4L60e (2004 GTO) with the stock converter and 3.90 rear gears with a Torsen style LSD.

 

The car already runs 11.9 @ 117 mph in the quarter on regular street tires shifting at 6300 RPM.

 

Now that I've had the same setup for a bit, I am interested in messing around with a mild turbo setup for the car. I already had plans is to yank the engine to replace the stock torque converter and replace it with a new billet 3200 stall unit (I was going to do this even if staying N/A since I already own the converter). While the engine is out I figured I would install a set of Katech rod bolts for a little extra insurance. I'll also go ahead and pull the pan (LS2 Corvette pan) and weld in a -10 AN bung for a turbo oil return. I plan on leaving the Voodoo cam installed, even though I know it isn't an ideal turbo grind.

 

As far as the turbo setup I am going to use a Holset HX50 that I already own (67mm compressor & 77mm exhaust wheels), a set of new LS3 Corvette manifolds (flipped) from a crate motor, and 2.5" mandrel bent stainless tubing (hopefully one piece for each side) from each of the manifolds to each side of my modified T4 stainless flange (for use with the HX50). I already own a rebuild kit for the HX50 from BAE, I will bead blast and clean the housings, and have the wheels balanced before reassembly, I might even polish the compressor housing for the hell of it.

 

I know the Holset HX50 turbo prob isn't ideal, but its what I have to work with (free), can't afford anything else right now, and figured it'd be better than a Chinese GT45 off eBay. Worse case, I'll run the Holset until I can afford something more modern from Garrett, Precision, etc.

 

The car is not an all out race car nor will it ever be. I have raced it from time to time, but mostly its just my cruiser on my days off. In other words, making 'all-out' power is not a concern.

 

I'll prob use a Cobalt SS (turbo) 2-Bar MAP sensor and run a Speed-Density tune to keep things simple. I am also going to run an intercooler out front and/or maybe meth injection instead (opinions?). I'll be keeping the boost in the 6-8 psi range for street driving (91 octane) and maybe as high as 12 psi with 100+ octane gas on race nights. Of course the A/F ratio will be a tad rich side and the timing/advance curve will be kept on the conservative side to keep everything happy and alive.

 

When its all said and done I would be more than happy with a 10.9 second pass on drag radials (which I now own) while maintaining the awesome street manners the car already has.

 

Okay guys, what do you think?

 

Take care.

Edited May 24, 2011 by Cable

[yessir]

Your going to kick yourself in the butt for not doing it sooner. Stock lq9, mild cam, pt88, 14.8 lbs and i put down 696whp on pump gas.

[Zfan1]

Very nice numbers, for a stock to mildish build w/ turbo set up.

[cockerstar]

I'm surprised that it hasn't happened sooner, Cable

I like the plan through and through, and hope to be running a very similar setup within the next few years (if I'm being honest with myself).

 

Keep us posted with lots of pics and how the setup responds!

[ColtGT4g63]

Maybe look into a boost-a-pump for that walbro? Or upgrade. And I would probably get some bigger injectors as well. I would certainly run an intercooler on there too, even if you've got methanol injection. Just to try and cool the charge as much as possible. When its all said and done and if its running right, I think your 10.9 goal will very possible. Hell, I managed to get a 10.9 without the turbo.

Edited May 27, 2011 by ColtGT4g63

[sq_creations]

Welcome to the Club. Its exciting seeing all this ls powered z's being turboed.

Aeromotive makes a 340 lph pump that is the same size as the 255's now or you could run a bosch 044 inline with the 255 in the tank but they are loud.

[Cable]

Well I took off the compressor housing today and the compressor wheel exducer has chip off the very end of one of the blades, maybe 1/8" or so. I was going to have the turbo rebalanced anyway, but should I hassle with finding another wheel or just run it 'as is'? I can't imagine it being much difference, but I am by far no expert on turbo mechanics.

 

Any help is welcomed and thanked in advance.

[ColtGT4g63]

I would still run it, and not think twice about it. I've seen people run turbo's that have got bent up fins and not even know it. Are you talking about the HX50? I probably wouldn't put anymore money into it then you have to. Considering you could swap to a borgwarner turbo for pretty cheap. How much would a new compressor wheel run you anyways? And how much does balancing run? You could probably get away without even balancing it if the chip is as minor as you say.

[Cable]

That was thought as well, here are a few shots of the nick/chip.

 

Also, while I was tearing the turbo down for bead blasting, powder-coating the compressor (buddy favor thing), and rebuild/balance I broke 3 of the 6 bolts that secure the exhaust housing to the bearing cartridge. Luckily I have another buddy good at extracting broken bolts, worse case have a machine shop drill them out and re-tap. I was quoted $30 to rebalance the turbo, which is being done even if I don't replace the compressor wheel.

[Cable]

Here are some before and after pics of the compressor housing. It was bead blasted, then powder-coated satin (semi-gloss) clear to keep it looking clean and keep the otherwise unprotected aluminum from getting that white corrosion like a battery terminals get. I had him avoid the turbo tag to keep it looking original. I'll prob just end up bead blasting the exhaust housing too and rattle-can it with some of that high heat stuff sold at the auto parts store. Its held up to several sets of headers I've done in the past, I might get lucky and have it last on a turbo housing as well. Of course I'll bake the paint on too.

 

I don't think I am doing so bad considering I still have ZERO dollars invested since the turbo was given to me.

Edited May 29, 2011 by Cable

[ColtGT4g63]

Damn that looks pretty good. If you can get it all said and done for less then a few hundred bucks, I would say you're in good shape. Is the turbine inlet a T4 or T6 flange?

[Cable]

T4

[sq_creations]

I would say run it also. What a difference some paint/powder coating can make. That is really cheap price to get it balanced too.

[Ben's Tuning]

You're definately gonna need more fuel. a 255 lph pump runs out of juice right at about 425 hp worth of fuel, especially if you have a rising rate fpr to make up for small fuel injectors.

 

BTW my math skills are a little rusty, so bear with me. Your 42 lb/hr injectors are good for 448 hp at 80% duty cycle, so they'll be maxed out on anything more than 5.3 psi (based on stock efficiency numbers of the engine, i have no way to account for the efficiency of the new cam), so... yeah.

 

Look into a new fuel pump definately, and possibly bigger injectors.

[Slammed68]

Ive abandoned my Turbo setup on my lq4 For some reason, and I have nearly everything you will need, for sale. Ill sell you the whole setup for one hell of a price and save you a massive headache. I have a brand new master power t76 q-trim, brand new tial q bov, new tial wastegate 42?mm, brand new seimens 60lb injectors, all the piping and fittings you would need and an intercooler. Its a 99% complete setup, you'll just need fuel pump, and map sensor. Let me know!

[yessir]

^ this post made me sad........

[Slammed68]

:/ All is well, Just wanna learn to drive it with the new suspension/brakes/rear end before I go making it stupid fast.