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Discussion Starter #1
hello i have a 350z with the vk56 going in it.. right off the bat im going to turbo it.. i see way to many dyno sheets of these motors dying off after 4000 rpms.

Is a t76 t4 turbo with a .82 a/r exhaust housing a suitable size for a single setup in the engine bay?:confused:

OR...

Are 2 50 trim turbos with .48 a/r exhaust housinhs a good size since each is on 4 cyl?:confused:

Looking to build this car to 500hp max. (not saying the turbo setup will get me there but this is the max goal for what I want out of this motor)

ANy help would be great.. Id like to know if these are good sizes since I can get these turbos easy , cheap and quick through a friend
 

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Unless you plan on doing a ridiculous amount of custom fab in the engine bay, i think youre gonna be hard pressed to stuff the uber wide vk56 in ther plus hang a turbo off one of the banks.

Im not sure on turbo size but i think a cammed VK56 with all the other goodies you can get for it (dont forget upRev) will be a silly amount of torque for that car.
 

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Turbo size is relative to what kind of power and what kind of use you're looking for. I will assume that since you're aiming for 500hp, which IMHO will be rather easy if you're building a Turbo'd 5.6 and have a capable tuner. I mean I took a lowly 2.0L Hyundai motor producing 109whp stock up to 270whp at only 17psi on a Mitsubishi td04 15t, which if you're wondering is tiny. However, my cars redline was 6500rpm's, which was conveniently where this turbo fell on its face. I then got a larger td-05 20G and at 15 psi was making over 280whp, but ran out of rpm's to take full advantage.

My true opinion of your idea would be a larger single turbo, since a 5.6L makes huge amounts of torque and falls flat up top. Of course all of this is relative to the RPM's you want to turn, cylinder head flow, injectors etc etc. Are you setting this up for drag racing? Highway runs? I will assume you don't plan to autocross the thing, but a track day wouldn't be out of the question? A T76 is going to be capable of making over 500whp at a relatively low boost level (12-15psi depending on supporting mods). Depending on the brand and exhaust housing that particular turbo can get upwards of 800hp. What are you doing to the bottom end to support this? Are you going to port and polish the heads? Buy new cams? The VK isn't designed from factory to rev enough for a turbo this size so you're going to spend some money to turn it up that high. If cheaps what you're going for, well good luck, first hand experience...boost is not nor will ever be cheap.

Here is a turbo size calculator to get you in a ballpark, keep in mind all of these numbers that are calculated are a reference not an absolute. Unlocking power will be in the hands of whoever is tuning for you. Squirrel Performance

Another thing you desperately need to consider is space. The VQ motor took up MOST of what was available, so I imagine the VK5.6 takes up all of it. Twins under that hood will be a serious feat considering all the piping for intercooling and charge pipes, plus downpipes, wastegates etc etc. Another option if you're out of space is a remote mounted setup. May want to troll around the LS1 forums, those guys find some truly awesome ways to get big parts into tiny spaces.
 

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hit up toomnymods.
 

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Discussion Starter #6
Unless you plan on doing a ridiculous amount of custom fab in the engine bay, i think youre gonna be hard pressed to stuff the uber wide vk56 in ther plus hang a turbo off one of the banks.

Im not sure on turbo size but i think a cammed VK56 with all the other goodies you can get for it (dont forget upRev) will be a silly amount of torque for that car.
Ill be running a rear mount radiator (located at the rear of the car). I have been working on designing this for a few weeks. THere will be no radiator in the engine bay. I will use the left header on the right side of the motor and the right on the left (making the collectors face the front of the motor. From there I will adapt t4 flanges ( 1 on each for twin setup) or merge the headers together for a single turbo setup.

My true opinion of your idea would be a larger single turbo, since a 5.6L makes huge amounts of torque and falls flat up top. Of course all of this is relative to the RPM's you want to turn, cylinder head flow, injectors etc etc. Are you setting this up for drag racing? Highway runs? I will assume you don't plan to autocross the thing, but a track day wouldn't be out of the question? A T76 is going to be capable of making over 500whp at a relatively low boost level (12-15psi depending on supporting mods). Depending on the brand and exhaust housing that particular turbo can get upwards of 800hp. What are you doing to the bottom end to support this? Are you going to port and polish the heads? Buy new cams? The VK isn't designed from factory to rev enough for a turbo this size so you're going to spend some money to turn it up that high. If cheaps what you're going for, well good luck, first hand experience...boost is not nor will ever be cheap.

Here is a turbo size calculator to get you in a ballpark, keep in mind all of these numbers that are calculated are a reference not an absolute. Unlocking power will be in the hands of whoever is tuning for you. Squirrel Performance

Another thing you desperately need to consider is space. The VQ motor took up MOST of what was available, so I imagine the VK5.6 takes up all of it. Twins under that hood will be a serious feat considering all the piping for intercooling and charge pipes, plus downpipes, wastegates etc etc. Another option if you're out of space is a remote mounted setup. May want to troll around the LS1 forums, those guys find some truly awesome ways to get big parts into tiny spaces.
I will be using all New stock internals. I am in the middle of a rebuild now. Block was rehoned and heads were machined. I will be using a GM 90mm TB. I will only be running approx 5-6psi and a high psi setting of 8psi lol... I am just tryting to get this up and running. If I feel like doing a full engine build in the future I will up the boost x3. (20-25 psi). But for now even 5-6 psi is gonna add power.
 

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Discussion Starter #7
are twin 50 trim turbos with .48 ar exhaust housings suitable for twin turbo setup?
or
are twin 60 trim turbos with .63 ar exhaust housings better for a twin setup?

Scooty Puff Jr. - "Are you setting this up for drag racing? Highway runs? I will assume you don't plan to autocross the thing, but a track day wouldn't be out of the question?" sorry forgot to answer this question. Car is set up for drift. I for sure will do a few 1/4 mile passes. Is set up for track so yeah a track day will definitely happen.
 

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sorry forgot to answer this question. Car is set up for drift. I for sure will do a few 1/4 mile passes. Is set up for track so yeah a track day will definitely happen.
Drifting...well a big turbo on a big motor will work, but I would look for something like a Turbonetics or Garrett with ball bearings,and lightweight turbine wheels for quicker spool. On average the ball bearing turbo's are 200-400rpm's quicker spooling than conventional bearings. Doesn't sound like much but it will prove itself. Are you going to attempt to alter the engine mounts? For a drift/track setup, I'd try and tuck that engine as far back into the firewall as possible, even if that means some custom tunneling for the engine and tranny. Back off of those front wheels would be ideal. I am sure you know this since you've gotten this far but weight too far forward is going to make the car twitchy and unpredictable and the VK has a bit more mass than the VQ.
 

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Discussion Starter #9
Drifting...well a big turbo on a big motor will work, but I would look for something like a Turbonetics or Garrett with ball bearings,and lightweight turbine wheels for quicker spool. On average the ball bearing turbo's are 200-400rpm's quicker spooling than conventional bearings. Doesn't sound like much but it will prove itself. Are you going to attempt to alter the engine mounts? For a drift/track setup, I'd try and tuck that engine as far back into the firewall as possible, even if that means some custom tunneling for the engine and tranny. Back off of those front wheels would be ideal. I am sure you know this since you've gotten this far but weight too far forward is going to make the car twitchy and unpredictable and the VK has a bit more mass than the VQ.
I really would like to do twins on this setup.. with the way its setup the twins would be easier servicing if needed.
I was told to look at gt28 turbos with a t28 flange for a twin turbo setup.. any input on this?
I will not be able to run ball bearing turbos for now since I will need 2 of them. Ill be using journal bearing Precision turbos or Garrett. The mounts are already made. I have a deal with MckinneyMotorsports who have already done this swap and produced these mounts. Also the front cyliners of the V8 will sit were the middle cylinders on the Vq were. THat is pretty par back in there.
 

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I really would like to do twins on this setup.. with the way its setup the twins would be easier servicing if needed.
I was told to look at gt28 turbos with a t28 flange for a twin turbo setup.. any input on this?
I will not be able to run ball bearing turbos for now since I will need 2 of them. Ill be using journal bearing Precision turbos or Garrett. The mounts are already made. I have a deal with MckinneyMotorsports who have already done this swap and produced these mounts. Also the front cyliners of the V8 will sit were the middle cylinders on the Vq were. THat is pretty par back in there.
Well that would be a horse of a different color. If you're definitely going twins, then a pair of GT28's might be alright, but the GT28's by Precision or Garrett are dual ball bearing and both come with t25 flanges on the turbine, which should mount to any newer t25/t28 flanges you would have welded onto your manifold, but I would double check that. They have either a .64 A/R or a .86A/R, I think you'd be better with the .86. However, a single one of these turbo's from either company is going to cost you over $1,000 a piece. I actually had purchased a GT 2871R for my Tiburon before I decided enough was enough, and I spent over $1200. You would probably want the GT2876R's, which are about the same price. They spool quick and each one is good for around 450whp IIRC. These aren't the same as the Nissan factory t28's that came on the S15's, those were/are good for around 300-350whp when modified properly, IIRC.

And if you got your motor mounted back that far, then whoever is sorting the chassis is a professional. I have heard of McKinney Motorsports, but for some reason I thought they were in Texas...must be someone else.
 

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Discussion Starter #11
Well that would be a horse of a different color. If you're definitely going twins, then a pair of GT28's might be alright, but the GT28's by Precision or Garrett are dual ball bearing and both come with t25 flanges on the turbine, which should mount to any newer t25/t28 flanges you would have welded onto your manifold, but I would double check that. They have either a .64 A/R or a .86A/R, I think you'd be better with the .86. However, a single one of these turbo's from either company is going to cost you over $1,000 a piece. I actually had purchased a GT 2871R for my Tiburon before I decided enough was enough, and I spent over $1200. You would probably want the GT2876R's, which are about the same price. They spool quick and each one is good for around 450whp IIRC. These aren't the same as the Nissan factory t28's that came on the S15's, those were/are good for around 300-350whp when modified properly, IIRC.

And if you got your motor mounted back that far, then whoever is sorting the chassis is a professional. I have heard of McKinney Motorsports, but for some reason I thought they were in Texas...must be someone else.
Ill look into the gt28's I'll look into OBX turbos ( there will be some frowns on this but as all newer companies they gotta start somewhere... what did people think of garrett when they first came to be?) I heard OBX parts are getting good and alot of people are using there products... I'd like to get precision turbos but we will see what the cost will be...

MckinneyMotorsports is located In California.. I made them a trade for there vk56 350z mount kit for a sr20det mount kit for the 350z. I just finished an sr20det swap in my Z when I came across the titan v8...
 

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OBX makes Chinese knockoff's of other companies hard earned R&D. They will never get my business. A single would be easier to service than twins since you only have to deal with one. It will be cheaper that way. A T76 would do much better with an a/r of 1.08 +/- some. an a/r of .80 range will make for really quick spooling, but will choke the motor up in the higher revs causing too much back pressure.
 

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Discussion Starter #13
OBX makes Chinese knockoff's of other companies hard earned R&D. They will never get my business. A single would be easier to service than twins since you only have to deal with one. It will be cheaper that way. A T76 would do much better with an a/r of 1.08 +/- some. an a/r of .80 range will make for really quick spooling, but will choke the motor up in the higher revs causing too much back pressure.
But cant this be bypassed by a external atmospehric vented 38mm wastegate and a 3.5 down pipe to evacuate exhaust much faster?,,,,, not giving it a hold up and chocking it?
 

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The turbine will still choke up the engine with too small of an a/r. The waste gate just vents off exhaust flow to regulate boost psi. It shouldn't be needed as a band-aid for an incorrect a/r ratio. Someone a bit more knowledgeable than me about the finer points of turbos will chime in soon I'm sure.
 

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Unless you plan on doing a ridiculous amount of custom fab in the engine bay, i think youre gonna be hard pressed to stuff the uber wide vk56 in ther plus hang a turbo off one of the banks.

Im not sure on turbo size but i think a cammed VK56 with all the other goodies you can get for it (dont forget upRev) will be a silly amount of torque for that car.

Fitting twins isn't hard.

Where do you want the power? The higher end? Low end? I would think a nice fat midrange would be beneficial since you can have much faster rev response and wont have to wait for the motor to rev out to get you to start sliding. My only drift experience was in a 1983 Datsun 280ZX-T and that thing had a T3 that would spool to 12PSI by 4,000RPMs with a rev-limiter at 6,5. I could keep it in second for most of the run with maybe an occasional upshift to third for more smoke.

I would personally go with twin gt3071Rs. Should spool quick but still be able to feed the beast 5.6L in the top-end.
 

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Discussion Starter #16

Fitting twins isn't hard.

Where do you want the power? The higher end? Low end? I would think a nice fat midrange would be beneficial since you can have much faster rev response and wont have to wait for the motor to rev out to get you to start sliding. My only drift experience was in a 1983 Datsun 280ZX-T and that thing had a T3 that would spool to 12PSI by 4,000RPMs with a rev-limiter at 6,5. I could keep it in second for most of the run with maybe an occasional upshift to third for more smoke.

I would personally go with twin gt3071Rs. Should spool quick but still be able to feed the beast 5.6L in the top-end.
I want some top end power. THe 5.6 is a great motor but plateaus and drops after 4-4500 rpms. I want as much power as the motor has from 1000-4000 rpms all the way to redline. (id get an sc and call it a day but that is too much cash. twin setp is cheaper to build with good parts like precision and tial.)

gt30's? was thinking that.. how are twins rated at on the psi level? Example: If I regulate each turbo with a tial wastegate that has an 8 psi spring, will I see 8 psi on the boost gauge or 16psi?
 

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Discussion Starter #18
The manifold pressure will be at 8psi but the turbos will flow as much air as a big turbo pushing 16psi.
I have heard pushing 8psi is the max on a stock motor with the providing uprades such as larger injectors and uprev tune. In your opinion is 8 psi safe on these motors?

Found a precision gt40 with a divided .96 ar exhaust housing.. people kept saying that the single would be easier to deal with so I checked. Is this an appropriate gt40 turbo for the Titan motor?

Im trying to view all ways of Fprced Induction for this motor.

Thank you
 

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I think the VK56DE is easily capable on stock internals of 550-600HP with a VERY safe tune. Meaning this will be on 109 octane with methanol injection. A good daily driven number would be 400-450HP.

But if you're going to be putting this much money into cramming a VK56DE into a 350Z I would go full standalone. I don't know if UPREV offers that option but I would contact HALTECH and see if they can help you out.

Remember that "8 psi" isn't a very good indication of how much or little an engine can handle. 8psi on a t3 is completely different to 8psi on a gt40. Now 8psi through a pair of gt3071rs would be fine. You'll probably see 450-460WHP depending on your supporting modifications. Which would be safe. But that is VERY dependent on the tune.
 

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i went with a GT4094R "hybrid" the a/r is a .96 and i hit full boost by 3600 rpms of 8psi.. This isnt too bad considering i have a 3200 rpm stall and my turbo is mounted under the cab.
for a frontmount a .85 to 1.01 a/r would be fine with a 67-72mm turbo..
 
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