Originally Posted by Mr.Squeeze (Post 2277989)

This is very interesting that boost falls off in the upper rpm's .With my car my boost holds well all the way to red line but I am experiencing backpressure.

What kind of boost controller was used?.

Originally Posted by ENT-Z (Post 2278034)

Jason has the same controller as me, HKS EVC-S.

Originally Posted by Boosted Performance (Post 2278073)

That is strange because a person with an even larger turbine (same kit), and less psi is experiencing boost drop. Maybe these things are not being set properly? Just a thought I guess..however the comparison in flow between the vq37 and the V8's sure says a lot.

Originally Posted by Boosted Performance (Post 2277869)

Just to touch on that....


I will be doing a test on the next local dyno tune comming up in a couple of weeks here to figure this boost thing out.

I have done a lot of research, and it seems that the 1.32 a/r housing may just be optimal for these engines in the high RPM's. The dyno Gale posted is with the 1.15 a/r housing, and it still spools VERY fast. Because it does spool so fast, the turbine may still be a bit of a restriction in the upper RPM's. It makes perfect sense, but needs to be proven. To do this, I will log the EBP (exhaust back pressure) on the identical housing for a local tune with the 1.15 a/r housing. This is the exhaust pressure just before the turbine housing inlet (not after the turbo). This will give me (and I will share this as I do everything) a solid idea of what is going on, and if a larger turbine is indeed the way to go. This was my suspicion with with the 1.0 a/r housing, hence the upgrade in size. It did not work out as I had anticipated.


This engine is very efficient, and flows so well (and a lot) in the 6,000 to 8,000rpm that these (smaller) turbines may be a bit of a restriction. I have spend a lot of time trying to figure this out. I have also talked to a couple of shops that run these turbos on stroked 2JZ's, and they are making 700whp with these turbos and the 1.15 a/r housings. The guys are also saying that they would not even think about going to the 1.32 a/r housings as they are "for V8's". I am starting to think that the 370z engine at 7,500rpm flows a lot more than a V8 at 5,000rpm (for example). I also have a customer making 580whp with the identical twin scroll kit on a 350z, and the boost is solid from 3,500rpm to 7,000rpm on a 350z. But then again, on the VQ35, there is no point of going any higher with the RPM's, and there is a 200cc displacement difference.



It seems like the boost holds just fine up to about 6,500rpm, and then falls a bit after that. I am not sure why the EBC is unable to hold the boost steady/flat. I will get to the bottom of it, and as mentioned will report back.

Originally Posted by elperuano (Post 2278130)

I'm using the same hks boost controller as well

Originally Posted by Mr.Squeeze (Post 2278076)

So we all have the same boost controller Gale and my self got tuned by the same tuner /same dyno

Originally Posted by Mr.Squeeze (Post 2278080)

When Vince tuned my car he set my boost controller I wonder if he set Gales when he tuned his car .

Originally Posted by Mr.Squeeze (Post 2278080)

When Vince tuned my car he set my boost controller I wonder if he set Gales when he tuned his car .

Originally Posted by GaleForce (Post 2278937)

Not only did you get my numbers first, you also got the digital copy of my graph first! :bowrofl:

Vince did explain that to me... I forgot most of it until you mentioned it again. I should hire someone to record my conversations so I can play them back later to refresh my memory. :p

Originally Posted by XwChriswX (Post 2278944)

I'll send you my resume, if you could put "Driver" under list of job requirements that would be great too. :bowrofl:

Originally Posted by GaleForce (Post 2278951)

Send it. I'll put it in the pile :bowrofl:

Originally Posted by GaleForce (Post 2278937)

Not only did you get my numbers first, you also got the digital copy of my graph first! :bowrofl:

Vince did explain that to me... I forgot most of it until you mentioned it again. I should hire someone to record my conversations so I can play them back later to refresh my memory. :p

Originally Posted by Boosted Performance (Post 2278987)

Oh no, you can't pull that on me this time.

Vince posted the graph in your build thread. I just copied the link and pasted it here.. :)

Originally Posted by Boosted Performance (Post 2278477)

So, I just spent some time on the phone with Vince.

To sum it up, the boost is nothing to worry about. The car (as you can see by the HP curve) continued to make more power with the higher boost (+50whp over spring pressure run), even though it looks like it is tapering off.

There are many variable at play (including VVEL, and the dyno MAP sensor), and since the car already made very good power, there was no need to spend a lot of time with the EBC settings to try and flatten out the boost curve. It also takes extra time to really dial in an extra few psi (small increments over base pressure) of boost with the EBC like we are trying to do here.

Originally Posted by Boosted Performance (Post 2281996)

Something worth linking:

R/T Tuning – Dyno Tuning & Engine Performance Specialists

Originally Posted by m3chhawk (Post 2307249)

Update? :eekdance:

Originally Posted by m3chhawk (Post 2328316)

Hey Sasha,

Trying to get stuff ordered and ready :excited:

Are the fittings on the oil cooler 8AN or 10AN?
I'm going to run one of these on each side for oil pressure and oil temperature:
JEGS Performance Products 110530 JEGS Fuel Pressure Gauge In-Line Adapter Fittings

Thanks dude!

Originally Posted by puckshaw (Post 2505643)

What's the expected delivery time? I'm getting tired of waiting for my MHI kit...