g35life

iTrader: (-1)

Hey folks,

Long story short... I had a turbonetics build on my DE... made 450whp 370trq on a dynapack. It lasted 6k miles and blew a rod. It was an old engine and stuff happens.

Since then I have sold all of my turbo parts and completely turned the car back to stock. Including a 50k mile JDM engine as the replacement.

I am now getting the itch to go back boosted. I have a great welder who can help me build a rear mount turbo kit as well as the cold side.

This time around I don't plan on big power at all. I want the car to last and just have a little extra power as well as make cool sounds.


My plan is to keep the stock clutch. Do colder spark plugs, wideband and boost gauges. Possibly a mac valve with 38mm wastegate, 4psi spring.

Honestly my goal is 360whp 335trq aprox.... Stock being 230whp 218trq ... these numbers should be safe and would keep the car interesting enough for me to enjoy for a few more years.


Questions.....

What would be my first limitation once my tuner starts dyno tuning with uprev/arc .... stock fuel pump or stock injectors or stock maf ?

After doing the engine swap in my driveway I do not want to blow this one up. Its a low mileage motor that does not burn oil!

I also do not want to trash my oem clutch.

So yea, any input on the limitations above helps!

i8acobra

iTrader: (6)

Fuel pump. Then clutch, then injectors, then MAF.

bealljk

iTrader: (13)

Go ahead and bump your power goals up to 400hp and 375 ft-lbs … that’s very safe and very attainable on the platform. 4psi is only going to make 300hp to 320hp. You’ll need closer to 8psi to 10psi to get into the high 300hp / low 400hp range

A rear-turbo setup is a very good way to get some more power - I’ve done a bunch of these rear-mounts and feel free to messag me if you have questions.

what are you going to tune with?
Are you going gasoline or e85?


What Cobra said:

You will need to upgrade your fuel pump and injectors … Go with an AEM 340lph pump and Injector dynamics 1050cc - these will be plenty of fuel and for how important fueing is to your AFRs dont skimp out on it.

I think you can make 400hp on an OEM MAF but you can solder in a 40k ohm resistor into your MAF harness to re-scale it and make the required modification in Uprev.

Add an oil cooler

g35life

iTrader: (-1)

If I were to just do a walbro 255. keep the rest stock. what kind of numbers on a dyno with 80% injector duty cycle? oem.

g35life

iTrader: (-1)

psi is relative to the turbine size. you can make 380whp or 480whp on both 10psi all depending on the turbine size. the bigger turbo moves more volume of air at the same PSI as the small turbo which in turn moves less volume of air... at same psi, all due to the surface area of the compressor

and... i mean I know 375trq 400hp is attainable quite easily. I am simply not willing to run that power level. A stock 03 g35 dynos at 230whp and 220trq. I think making 360whp and 320trq would be a fun little car, much more reliable than running an extra + 55trq as you've stated. These motors weren't meant for boost. the rods are tiny... trust me... I've seen them all over the road when my first build blew up.


looking at the dyno graph .... of a bolt on 370z...

https://specialtyz.com/blog/wp-conte...8/dynotune.jpg


332 and 274 it made.... im sure its a fun car... a turbo VQ35DE at 360whp and 320trq would have no trouble with that 370z ... thats another 46trq on dyno which is like .... 55trq crank.

bealljk

iTrader: (13)

You probably could? Im not 100% sure where the cutoff is for the 255lph but I wouldnt find out…Just use a 340lph (or not, do what you please)…

In the real world youre not getting 480hp out of 10psi - not with OEM compression - 10psi will be high 300hp to low 400hp. On paper maybe you’re getting 480hp but not in real life. In-reality - horsepower is made by airflow, airflow isnt boost, and boost is wasted airflow.

Sure - do as you please - if all you want is 360hp / 320tq than dont let me stop you


debatable … the VQ has plenty of boosted applications from the factory. I’ve covered a few of the reason why I think the VQDE ‘could’ have been OEM boosted here:
Post #33
https://my350z.com/forum/autocross-r...ack-build.html

giggles to himself
Just one blown engine under your belt?

I tend not put much value on things I read on the internet (reliable or not) but yes, a turbo’d engine (that is arguable more efficent) than a slightly bigger NA engine (despite the advances in technolgy, higher CR, higher redline, better components) will do better. And this comes from first-hand experience - not an internet graph.

i8acobra

iTrader: (6)

That's not at all how that works.

You should probably let Nissan know. They've been boosting it for years.

g35life

iTrader: (-1)

You sound so butt hurt... every single reply.... seriously dude whats the deal here? Its a forum... if you know everything why even be on here?

The vq35 is a high compression motor, its open deck. rods are popsicle sticks. ring gaps are designed for N/A ... turbo engine ring gaps are greater than that of an N/a motor. There is more heat in a turbo engine hence more thermal expansion of the rings.

i8acobra

iTrader: (6)

The VQ motor handles 8 to 10 psi with no problems. It's been done for literally decades. There are thousands of boosted VQ's with over 100k miles n them with no problems. Can you blow a VQ with boost? Of course... If you do it wrong. Telling you you're wrong isn't being butt hurt.

bealljk

iTrader: (13)

Im not trying to gang-up on you but anyting I say take in a positive manner and I would do the same with every other member - yes it is a forum and it’s an open discussion and I appreciate and respect what you are saying but you are conversing with people who have more experience and more knowledge than you…dont take it the wrong way (just listen and learn what people are saying).

I’m on my 4th rebuild with my ‘bigger’ built block in the white z, I’m on my first built block in a track g35 - both turbo’d. Picked up a q40 a few years back, brought it back to life - I think I’m up to my 7th or 8th z / g / q chassis - down to the aforementioned 3. Im still learning and I know there are other members that have deeper knowledge bases than I.

Dont get upset, hang around long enough and you’ll see this cycle play-out.

I dont know that I’d call 10:1 high compression? It’s probably somewhere in the middle?

Did nissan mean to turbo the 350z engine? Probably not - wouldnt make sense to have their mid-level $30k sports car make anywhere near the hp of their future gtr re-vamp. Why buy the $100k 480hp gtr when you can buy a $30k 450hp 350z?

So, I’d agree with you that they didnt intend to turbo the 350z (at least not initially) and so yes, they put smaller, lighter, not-as-robust rods in it, and of course they designed the engine for NA. Further (let me speak out of the otherside of my mouth) you have an engine that make 230 to 250hp (in it’s NA unmodified form) yet it will take 450hp with decent longevity. What was Tim Hampton pushing out of his vortech equiped OEM block? Well into 500hp? Ask Tim how his OEM rings held up to double OEM power levels.

So, yes, the rods & pistons are not as strong as billet/forged counterparts but they were able to take 2x what nissan designed the engine to make.

All that to say - it’s well documented that the VQ is a turbo-ready assembly/block.

iideadeyeii

iTrader: (6)

550 cc injectors, you do not need a fuel pump for 4psi
You'll be at ~335tq and low ~300whp because I used to run 4psi(5.5 psi at 3500 that seeped down to 3-4psi at redline) for a very long time at 295whp 335tq, but my timing was very retarded. This was good for a 12.9 at 107 on cheap 275 rears
The oem clutch held for a few thousand miles on this and a brand new oem clutch (upped timing) didn't hold 2 runs at the track, so you will need to upgrade the clutch. I'm running a 6-puck and it feels great.

bealljk

iTrader: (13)

For what it’s worth:

each 1psi of boost adds about 20hp to 24hp on the DE and HR engines, added to a 240hp base will get you your total hp.

4psi on a DE will add 80hp … plus your 240 puts you at 320hp.

g35life

iTrader: (-1)

dang... id hate to have to do a clutch... its sucha pain job in the driveway without a lift.

thanks for sharing your experience with your build.

g35life

iTrader: (-1)

Im sure there are plenty of boosted VQs that held up.

There is also a ton of them that let go few thousand miles after being boosted.

Those who had a negative experience with the VQ letting go... usually do not come back on our forums and share their experience. There are those who do a full build such as yourself and continue on with the hobby. But there is a huge amount of boosted 350z/G35 that let go and owners cut their losses and haven't returned to the VQ community. We'll never know the percentage of those who held up and those who let go.

End of the day... a vq35de in its stock form is a reliable engine and they go for long long miles... once you introduce boost and increase the power two fold they are no longer as reliable as in the stock form. Same goes for power levels... there is no safe limit on these motors in terms of power. One motor is different from the next. One motor might be kicking around at 380trq for years!!! without loss of compression. While another motor lasts 5 pulls at 330trq. All things held constant (same tuner etc).

bealljk

iTrader: (13)

I think ’most’ builds that fail are due to the installation of the kit or the tuning.

Turbos/SC/Nitrous are not inheriently bad - but when used incorrectly they cause damage.

Hit or miss (if you ask me) there are a few members on here who have build threads that you can see the ups/downs. I think all the facebook groups / youtubers / IG platforms have taken people away from the forums. And more often than not, you only see the final product and not what went into the build nor it failing and what it takes to get back to square one.

Pesamistically - they all fail … whether the owner rebuilds or moves on to another platform is another story. I love these cars, Im pretty well invested in them, and I love every minute of every build. But yea, its not like theres a reliable database of how many are still on the road.


​​​​​​​And we all come back for more!

g35life

iTrader: (-1)

Which kit were you running?

What specfic turbo ?

Why did you seeped down the boost 3.5psi at redline... while you had 5.5 psi at 3500? It's really the torque that we gotta be mindful of, not sure why only 295whp at 335trq? Maybe you can better explain your setup?


Thanks!

iideadeyeii

iTrader: (6)

I'm running the Godspeed kit. (Turbonetics replica)
I had wastegate creep which was fixed with a boost controller last year.
My timing was around 12 degrees retarded more than it should of been, which explains the low whp.
I've dropped my tranny 3 times in the last few years on my driveway with jack stands. It's actually an easy car to do it on. I'm pretty sure I can do it in less than 4 hours including jacking time now.

i8acobra

iTrader: (6)

Like I said, they're plenty reliable when done right. I've lost count of how many turbo Nissan motors I've built. From VG30DETT's to VG35's (and a VG40) and VR38's. Never had one fail as the result of being boosted. Seen one fail when it was run with no oil and one when the turbo came apart and the engine ingested the turbine. My shop did nothing but Nissan's for 5 years.

g35life

iTrader: (-1)

Hey I don't find the job hard... I did an engine swap on the car in the driveway. What I found hard was fitting the transmission back.... Were you using a transmision jack? Its sucha PITA to get it to line up with a regular jack

g35life

iTrader: (-1)

What size turbo would you suggest? for let's say 350whp 320trq? rear mount