Q45 TURBO PROJECT

[craigztoyz]

Cool Videos that you posted on there. Some great video links off it too, 1 of slims Z for instance. Are you getting detenation? are you running a led knock sensor monitor it? Had one on my GN, was useful

[sijoko]

Cool Videos that you posted on there. Some great video links off it too, 1 of slims Z for instance. Are you getting detenation? are you running a led knock sensor monitor it? Had one on my GN, was useful

I'm not noticing any detonation but that doesn't mean it isn't happening. I've got water injection just in case. I'm going to be pulling the plugs to replace them with NGK Iridiums so I'll post up some pics for all to see.

Here's a vid of the car on startup so we can hear the exhaust.

http://youtube.com/watch?v=nzm0lOOpdVE

[craigztoyz]

We apppreciate keeping us up on your sweet ride. Keep the videos coming. I wish there was a video section, in the VH page, set asside for just Videos of the VH either moddified, or swapped.

[konatown]

Any updates sijoko? How is it?

[PanzerAce]

I'd also love to see an update.

Any idea for what kind of kg or lbs per minute of air you're pushing? psi numbers are great, but for my future build, there's going to be a fair bit less restriction on the intake system, so I'd like to know the actual flow.

[sijoko]

I had the car parked at my Mom's place in Atlanta for about a year so not much has happened since then. Recently, I moved to OKC, so I went and picked up the car with my friend. Got it back here without any problems. The trans is getting tired, a bit noisy driving around in traffic but it still shifts fast under full throttle. I also increased the boost to 7.5 psi and started to use methanol with the water injection for extra fuel. I also replaced the louvers on the hood with a different style which I looks better.

As far as CFM numbers, I am running a T-76 which flows 46 lbs/min at 8 psi.

[bfreehill]

wow... soooo clean.very pro install.

[PanzerAce]

Cool. Any idea how much whp you're putting down?

[sijoko]

Cool. Any idea how much whp you're putting down?

My guess is that it's putting out over 460 hp. The car feels so much faster than before. The turbo I'm running has a huge turbine so I think it is making more power than I originally anticipated.

[efeezie]

Hey sijoko, didnt know you actually moved here. Come bring the car by the shop (abelracing.com) sometime. We also have a in house dyno if you need.

If you havent found out about it , sign up on nismokc.com

[elwesso]

do you think you could see 10lbs with bigger injectors? That would be sweet!

[sijoko]

do you think you could see 10lbs with bigger injectors? That would be sweet!

I think I can get by on 10 psi with higher fuel psi and an auxiliary inline fuel pump. Plus, I've got the methanol injection to help out. The hardest thing is to not to be greedy with the boost. LOL.

[elwesso]

are you eventually going to decompress the engine a little bit so you can actually start USING that huge-azz turbo???!

[sijoko]

are you eventually going to decompress the engine a little bit so you can actually start USING that huge-azz turbo???!

I don't know. Here's my dilemma: A lot of people say that you need to lower compression and use forged pistons to run any decent boost. But there are plenty of stock 4 bangers running over 12 psi and have no problems as long as the tuning is correct.

So, if the VH45DE is such a strong engine, why can't we run 12 psi with the proper tune? Do we even need to decompress?

[Carl H]

its all in the tune...

[PanzerAce]

Well, lower CRs let you run more boost, which is where you are going to get your power. Also, with a good tune, it gives you a little more of a safety margin.

That said, if you manage to get it on a dyno, I'd be interested in seeing the whp numbers (with two different PSIs if possible, but I'll take what I can get )

[elwesso]

I don't know. Here's my dilemma: A lot of people say that you need to lower compression and use forged pistons to run any decent boost. But there are plenty of stock 4 bangers running over 12 psi and have no problems as long as the tuning is correct.

So, if the VH45DE is such a strong engine, why can't we run 12 psi with the proper tune? Do we even need to decompress?

i was more thinking about the prospect of making stupid power, like 15-20lbs..

[Carl H]

again all in the tune.

[sijoko]

i was more thinking about the prospect of making stupid power, like 15-20lbs..

Now that is stupid power.....LOL. Depending on the turbo, you are going to be making upwards of 600 hp at 15 psi. Even if the stock engine can handle it, the rest of the drivetrain would probably give up the ghost. The car is too heavy for that kinda of power on the stock diff, driveshaft and transmission.

Today, I was merging onto the highway and punched it with the car in 2nd gear and rode it out to around 80 mph. It was great and then I thought to myself, " Imagine how much faster this car could be if it weighed in at 3500 lbs instead of the current 4000+ lbs." Of course, I could just turn up the boost but then I begin to tread on thin ice.

Anyway, I'm hoping that somebody else will reach the limits of the stock block. I can't afford an engine rebuild at this time.

[sijoko]

again all in the tune.

I'm curious as to how many stock non-turbo 4 bangers such as an SR20DE can handle 15-20 psi.

I've heard that the Honda guys run a decent amount of boost with a good tune. Here's a dude that is running 10 psi on a stock S2000 with 11:1 CR: http://www.s2ki.com/forums/ind...6511
Modified by sijoko at 1:00 PM 3/3/2009

[Carl H]

you'll run out of fuel and maf before you run out of block strength.

[PanzerAce]

Now that is stupid power.....LOL. Depending on the turbo, you are going to be making upwards of 600 hp at 15 psi. Even if the stock engine can handle it, the rest of the drivetrain would probably give up the ghost. The car is too heavy for that kinda of power on the stock diff, driveshaft and transmission.

Today, I was merging onto the highway and punched it with the car in 2nd gear and rode it out to around 80 mph. It was great and then I thought to myself, " Imagine how much faster this car could be if it weighed in at 3500 lbs instead of the current 4000+ lbs." Of course, I could just turn up the boost but then I begin to tread on thin ice.

Anyway, I'm hoping that somebody else will reach the limits of the stock block. I can't afford an engine rebuild at this time.

Now you know why I want to SC one of these for my Z.

The stock block probably is good for basically anything, the stock pistons and rods though are most likely the weak points (well, that and the springs, valve float = bad)

[Carl H]

in my experience thus far its not the rods that are weak but rather the rod bolts.pistons are the 'weak link' in the turbo chain followed close by the rod bolts; I've not seen a rod just break and go flying thru the block (not that it doesnt happen) but rather you see rod bolt failure which causes the catastrophic damage.

[sijoko]

in my experience thus far its not the rods that are weak but rather the rod bolts.pistons are the 'weak link' in the turbo chain followed close by the rod bolts; I've not seen a rod just break and go flying thru the block (not that it doesnt happen) but rather you see rod bolt failure which causes the catastrophic damage.

Interesting that you brought up rod bolt failure as the most likely scenario. That should only happen with rpms and not from cylinder pressure i.e. more boost.

So then, if we kept the stock 6900 rev limit, shouldn't we be okay?

[the_momo]

rod bolts would be an easy enough problem to overcome, im sure arp makes something that would work, if not a specific application.

anyhow, its really not the high compression that is the limiting factor in our engines (or any for that matter) but rather piston/ combustion chamber shape and top ring land strength.

with most factory pistons, the top ring land is much thinner (the portion of pistion from the top of the top ring groove to the edge of the top part of the piston) because, and correct me if im wrong, but it provides less of an area for unburt hydrocarbons to collect and promotes better emissions, at the expense of strength, where most aftermarket pistons are designed with thicker lands to combat this.

factory pistons also generally are domed (the piston is peaked/ridged at some point on the piston to raise compression) and can leade to uneven combustion at higher cylinder pressures, and detonation, which destroys ring lands, and again the aftermarked pistons, especially when dealing with lower compression, are dished to obviously lower cr, but also provide an even area for combustion, and thicker ring lands.

with things like diesels, they usually have pretty high cr's, but use flat pistons predominantly, and have hellatiously thick ringlands, also thick rings, just because of the high (really high) cylinder pressures.

i realize im generalizing, and there are certainly exceptions to this, but that to me is a good summary of what we are dealing with.

so for stupid power, some good rod bolts, maybe replace main and rod bearings and some good flat topped or dished forged pistons and we are good to go.

please feel free to interject, change, or whatever.

[elwesso]

the thing is though when you start talking about 15 lbs of boost you are probably not going to want the stock pistons anyway, regardless of if its too much compression or not... So, why not just bump it down to 9:1 and have basically have the freedom to add as much power as you want...

[sijoko]

VH45DE piston and rod assemblies:

[Carl H]

stock vh pistons are flat top and from that pic they dont look too far off of my rb20 stock pistons that i have sitting on my shelf.gotta love old school nissan, build it to hold 3x the hp it actually makes.rods look stout imho again rod bolts are the source of failure in my experiences thus far.

[PanzerAce]

momo, the only issue is that modern heads tend to have really good squish/quench characteristics, which is how modern engines can run 11:1+ CR ratios on premium gas, but my L series is almost maxing it out at 9.8:1. The only thing I'd be careful about when dishing the pistons is to try to make sure you can keep the same detonation resistance that the original design has.

[the_momo]

i stand corrected, and much more trusting of vh factory internals, they look quite strong ( i havent actually looked at those specifically before, i was more or less generalizing from what i have worked with)

and i also agree with the detonation resistance. really, thats the main goal with any design, and making something stronger, but more prone to detonation is just walking backwards.

i am interested on how much a factory vh can take and for how long. id be a very happy person if we can make them live around 450-500 with proper tuning for any decent amount of time.

time will tell, time will tell.