Supercharger TIPS

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Q45tech
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http://www.kennebell.net/techi...s.pdf

http://www.kennebell.net/techi...d.htm

Look and you will find a comparison of various brand 8 psi radial superchargers as to psi at various rpm on a 5 liter engine.

It appears that most don't make 8 psi @6,000 [engine volume too large] but they would on a 4.5 Q...........even the worst one made 1.7 psi at 2500 rpm and 4.0 psi by 4,000 rpm so I have been too conservative in my calculations. I appears that the science has improved with otimization in 4-6k range and bottom efficiency is up.

4.0 psi corrected for temp/sc drive loss would still net a 50 lb/ft improvement on a Q at 4,000 rpm.......25 more than a JWT ecu! By 6,000 the supercharger would be producing 45 lb/ft more net above the ecu mods....and 70 more than stock Q close to 30% improvement...........thus the typical 0.7 sec improvement .


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Eswift
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sounds like butter for a VG30DE

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Eswift
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get a slightly thicker head gasket to lower the CR, and use a zemulator to build some decent fuel and timing maps. the building blocks exist...

Q45tech
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The static CR is nowhere near the dynamic [running] CR on a Q the dynamic CR varies betweem 7.78 and 8.85...... not the published static 10.2 as most think. How else could it run on 91-93 average octane. At 6.0 psi boost the dynamic pressure is 12.46

http://www.rbracing-rsr.com/comprAdvHD.htm

Running CR is a function of rod/stroke ratio and cam duration.......how much past BDTC [68-48 deg] the intake is still open letting some of the air flow out {intake reversion] as air only flows in as the piston moves down. Once the piston starts moving back up the bore the air and fuel is forced back into the intake track.

The maximum gulp of air is by definition the peak torque rpm.

The problem is with supercharged air pressure most high performance NA cams are too big in duration..........why the 6.6% increase per psi boost never works out plus the ovelap designed to work at standard pressure just lets part of the extra good pressure flow out the exhaust wasting it [the Q has 28 degrees [11%] until 4900 rpm then it drops to 8 degrees above that.

Actually much better than most [maybe they had thoughts of supercharging the early Q engines] who knows?

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Eswift
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so effectively, cams from a VG30DETT would be a good transfer into a a VG30DE that has an added supercharger? More or less effective than the 1-2mm thicker head gasket option?

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Eswift
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first, maybe a stupid question, but does the J30 have variable valve timing?... i know some iterations of the VGs had it. If so, is this controlled by the ECU? if it is, exhast duration could be decreased at higher rpm, without changing the cams themselves

Russ3Z
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If the J30 did have the version of the VG30DE with variable valve timing, it was a relatively simple version, with a single stepped adjustment (10 degree I Think) at a preset rpm. I fished up a torque curve chart for it, and there's a rather pronounced jump at around 3200 rpm or so, so this may be where the timing is changed.

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Eswift
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your right, i looked through the manual and it seems its a change from 8 degree overlap to 18, which indicates an advance of 10 degrees. Im pretty sure the Zemulator could allow the point of this shift to be modified, although that would not help the exhaust duration directly. the overlap could be tuned a little for improvement under forced induction tho.

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Eswift
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just checked the 300zx manual and the intake valve advance is exactly the same at 10 degrees. i have a hunch that the activation RPMs are different. The advanced mode clearly allows for greater torque at a lower rpm, while the normal mode yields peak torque at a higher RPM. i bet the J30 VCT activates at 3200, which is probably a higher RPM than the 300zx VCT does. looks like a small place to get some much needed torque. need the zemulator.

Q45tech
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Eswift
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what was the point of the barrage of links? it IS good info, but i know all that...

maxnix
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One of the points is, if you don't have your engine designed from the begining for a turbo application, in adding one you you will seriously erode its life expectancy. Maybe to minutes!

Slap-on turbos and superchargers are a recipe for a bomb.

For everyday street driving, atmospheric engines in a mild state of tune work best. The larger the engine, and the more cylinders, the better it will perform, but the more it will cost to run and maintain.

Q45tech
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The VVT on all early Nissan works by oil pressure and the cutting off of same at around 4500 rpm.Regular [low intake advance] at idle for a smooth idle....around 1100-1300 rpm it advances by 10 or 20 degrees as the oil pressure builds against the spring. Around 4300-4500 the oil passage is shut off by a solenoid allowing the intake cam to return to low intake advance by spring pressure. How many rpms does it take both cams to shift...function of spring stiffness after solenoid has cut off oil pressure.

If you knew every thing in those post you are better than I am. I always find new things every day. It takes me 3-4 hours per day of research to keep up with forum.....then reading and responding to posts!

You will be tested and may be publically humiliated one day with a "I know all that atititude"

See I see you don't know everything because you are focusing on the intake opening point not the cam intake closing point which is 3-3.5 times more important and why the VVT was developed in the first place. Sure the intake open point moves but that is a side product.

If they could they would keep it at the same and not choak it off by reducing the overlap above 4600.

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Eswift
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i see now what you are saying about the closing point, i stand corrected...and i know i dont know everything. my previous post was made in a half-concious state.

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Eswift
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maxnix wrote:One of the points is, if you don't have your engine designed from the begining for a turbo application, in adding one you you will seriously erode its life expectancy. Maybe to minutes!

Slap-on turbos and superchargers are a recipe for a bomb.
I am not speaking of a "slap-on" application of forced induction here. First off, the only mechanical differences of consequence between the VG30DETT and the NA version are the pistons, the way the oil squirters are pointed, and the inconel exhaust valves on the TT. Of course, the cams are different as well. The limiting factor in applying boost to the NA VGDE engine will probably end up being the stainless steel exhaust valves.

Detonation is always an issue, but a well thought-out application of timing changes and intercooling can help enough to make it viable. Of course, bigger injectors are a necessity, as well as a nearly completely remapped set of EPROM maps.

Just recently it has been proven that 340 HP can be made on an NA engine that has only TT injectors, OEM TT turbochargers, and a remapped ECU. This was accomplished with no detonation, mind you. Detonation being the biggest worry by far in applying boost to a NA engine with a high CR, reliability might very well be decent.

Several NA Z32's have been running with supercharger with 7psi for several years now, at least one of them without an intercooler at all! As far as i know theyre still puttering along, with no failures. It should be noted that these Z32s had ECu maps designed for the stock twin turbos, which have completely different flow characteristics than the supercharger. This is a testament to the robustness of the block and its ability to survive adverse conditions, even with possible detonation due to incorrect mapping.

If a supercharger can be found that can provide the necessary CFM at 11 psi, an excellent supercharger system is entirely possible. Both powerdyne and vortech make units with promising flow characteristics, both of which i am currently researching.

Add to that an efficent 1 or 2 core intercooler, possibly air-to-water, and you have a very reliable system producing an excess of 300HP, reliably, on the NA VG block.

I agree that a poorly designed application is doomed to premature failure, and even a well-engineered application is doomed to a more distant failure. Of course, every engine has a finite possible lifespan right out of the factory.

so putting mederate-boost forced induction on a NA engine is no more detrimental than expecting 550RWHP out of a VG30DETT with stock internals. plenty have done it, and reliability is reasonable. long term reliability is definitely questionable, but thats not the point. anyone considering any of these torque-enhansers should very well realize that there is always a trade-off with reliability.

melted pistons? definitley a long-term possibility. perfect opportunity to get inconel valves and better forged, lower CR pistons.

maxnix
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Are there piston oilers on the VG30DE?

Engine durability will suffer, no matter what because of higher stress. I would start with a VG30DETT so I at least had the bottom end mechanicals optimized for boost.

Long term reliability is a big point for me.

Good luck!

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Eswift
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there are piston oil squirters in both the NA and TT blocks. TT pistons have special channels through which oil can circulate, hard to explain without a picture. both do have the under piston squirters, though.

the bottom end mechanicals: block, shot-peened crank, rods, are all the same for the VG30DE series. same in J30 as NA z32 as TT z32.

pistons are obviously different in the TT version.

long term reliability is an important point, but some has to clearly be sacrificed to make gains. [the question is how much, and no one can really predict without trying]

like i said, i bet the SS exhaust valves are going to fail before the pistons. (assuming detonation can be avoided)

ive still got research to do, and criticism always helps point out possible problems!

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Mayhem_J30
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Eswift wrote:
like i said, i bet the SS exhaust valves are going to fail before the pistons. (assuming detonation can be avoided)


I agree. The special alloy used on the valves in the TT was one of major differences between the two motors. More then likely has to do with the higher temperatures in the exaust from the turbo.

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Eswift
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i just looked up numbers on the two alloys:

by best guess for the two alloys are 440A SS and inconel 625: Yield Strength Tensile Strength % Elongstainless alloy 440A 415 725 20inconel 625: 517 930 42.5

besides the obvious difference in strengths, the ductility of the inconel is over double that of the stainless steel. I assume most valves that fail (other than piston contact) experience brittle fracture, and the ductility of the inconel might very well be its redeeming factor.

the thermal expansion values for the two alloys are similar, within about 5-10 percent of each other.

Inconel is about half as thermally conductive as the SS, and i bet it thrives in the VG30DETT.

inconel-its all about the molybdenum

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Eswift
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this sums up nicely what can be done on the NA VG using forced induction.

highlights the tuning process, and reliability factors.

http://www.twinturbo.net/net/v...08772

the dyno is of a VG30DE fitted with TT turbos and injectors. (maintaining the 10.5:1 CR of the NA)

VimyJ
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Fascinating! A J30 with 300hp. Better have the spoiler installed. Good luck with the project. I will see your see J someday.

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Eswift
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thanks mike, the spoiler is already installed, so it looks like the project is a go...haha

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Yep, you're half way there. :)

maxnix
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I thought this might be of interest to this thread:

(From http://www.fiendation.com/300zx/300zxfaq.htm)

Can I upgrade my non-turbo 300ZX to a turbo?

Short answer - Sorry, not really. The differences between the two cars are substantial - in addition to the turbos themselves, and their associated exhaust plumbing, the engine management computer is different, there are some internal engine changes, and a whole slew of other changes. Through the various aftermarket suppliers you can squeeze 250-260 hp out of your naturally aspirated Z, but you'll be hard pressed to hit 300 horsepower for less than $5,000 in upgrades. So the most cost-effective route is to sell your non-turbo for $12,000 or so, then go buy a used turbo for $15,000-$17,000. You'll save money, can get that color you always wanted, and when you start doing engine upgrades on the Turbo car, you can really get some power.

But I can make my non-turbo almost as fast as a turbo, right?

This is a discussion that comes up every once in a while on the various Z-car online forums. The answer is a mixed bag. Some people believe that you can take the lighter non-turbo 300ZX, invest a few thousand dollars in engine upgrades, and get it to 270 horsepower or so, giving the Twin Turbo a run for it's money. The jury is still out on this issue. However, one thing is certain - after all the money and modifications you sink into a non-turbo to try to reach 300 horsepower, the guy with the real Twin Turbo can spring $600 for an upgraded computer chip, and voila - 360 horsepower. If you want to go fast, get the turbo. If you really believe that the modified non-turbo is the way to go, because of it's weight difference and different engine response, well, let me know how it turns out. But don't say I didn't warn you - You'll notice that no one ever asks how to turn their Twin Turbo into a non-turbo...

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Eswift
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technology has advanced significantly since 1997. that is no longer an accurate resource, if it ever was.

Everything stated in the above dissertation has been subsequently proven wrong in the past few years.

maxnix
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Eswift wrote:Everything stated in the above dissertation has been subsequently proven wrong in the past few years.
So TT engines are not any more robust than NA engines?

Hmmmm....

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Eswift
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i have already discussed that in this thread. the only differences areoi pump: more pressure needed on TT to flow through turbosexhaust valves: inconel on TT for more temp and creep resistanceoil squirter: pointed differently for the obviously different pistons.different pistons: TT ones have oil channel underneath fed by squirters.

those are the only internal engine differences, and they apply directly only to turbocharger needs and to prevent against long term high temp wear.

Sure, you could state that the TT engine is more robust, but all of the parts that make this so can easily be swapped out. this robustness you speak of is merely long term high temp reliability.

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Eswift
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an example of said proof:

Subject: Can I put turbos on my NA? Posted by: AshsZ (FABio) on February 23, 2003 at 8:03 PM This message has been viewed 844 times. Message: The testbed:A completely stock NA engine plus only stock turbo bolt-ons. This includes manifolds, 5 speed turbos, plumbing, stock intercoolers, twinturbo injectors. The engine has 150K+ miles on it. Only problem with it - "Nissan Lifters, Guaranteed to tick everytime..."

While the dyno shop tech was strapping the car down, I cracked open the ECU to install the Zemulator and also strapped in a ConZult.

Our first pull was simply to datalog the run for map point datum.

BC dialed in to 8psi.

The very first pull yielded ~238HP, ~240TQ.

First objective - stabilize the A/F @ 12.0:1. After performing a few runs I had the A/F as flat as Bonneville.

At this point we were ready to begin increasing timing. The fail-safe program I sent earlier in the week had only 9 degrees of timing at this load range and the A/F was a bit on the lean side. It was experiencing detonation at anything above 9psi on that program which is what I had expected to see.

I began increasing the timing a few degrees at a time to watch the results come back from pull to pull. I ended up dialing in 20 degrees of timing which falls to 18 degrees after 4400RPM to eliminate the detonation we started experiencing.

Then we raised the boost to 11psi and performed another datalog run. After a few additional pulls to get the A/F curve stabilized for that loadband and increasing the timing, we hit 347RWHP and heard the clack of detonation. I backed down on the timing by a degree and performed another run to stabilize the car at 340RWHP@340TQ at 11psi.

We were noting that the boost wasn't coming on real strong so I retarded the timing in the low RPM range a few degrees to help the spool up. I managed to get the boost to roll in another 500RPM sooner.

After making a few more additional runs without making any changes to the program, the ECU stabilized and we were happy. The very last pull after the engine was quite heatsoaked (27th pull) it was still making an impresive 327RWHP without detonation at only 11psi.

We didn't stop there saturday. We weren't going to rest on our laurels. We weren't going to be convinced until we got real-world drivability testing. What'd we do? Took it to the drag strip, of course. We pulled a 13.2@104 in the quarter mile.

Later on race fuel was added to the mix and were able to run 15psi of boost without detonation. Other than the lifter tick, the engine is running without any issues and it has by now about 400 miles on it.

I would like to say a few things about the guys at Z1 Motorsports - one thing in particular that stands out from anything I expected - these are some dedicated Z guys. I rolled in at about 11pm friday evening, stayed up till ~4AM wrenching with them and I finally retired. I got up around 10:30 and went out to the shop where they were still busting ***. I am still floored by their drive and these guys have my backing if anyone asks. This car belongs to Todd of Z1 and I feel honored to have been asked to do this and given the opportunity and trust to tune such a prototype.

At this point, I have come full circle with the NA. I bought one, got the horsepower bug and wanted to put turbos on my NA as well as spent a good deal of time working some mathematics a long time ago concerning cylinder pressures/temperatures involved with forcing air into the NA engine and speculating on what the maximum boost would be. Unfortunately at the time I didn't know much about the ECU and how it was structured and what kind of flexibility it really has once you can get into it and finely tune everything. If I had pursued the "turbos on an NA" at the time, it would certainly have met a catastrophic fate as using either an NA or TT ECU would not have provided the proper ignition timing and fuel delivery to make a reliable powerplant. I had no presumptions on what this turbo'd NA would actually do and was delightfully suprised to see it at stage3 twinturbo performance. I am fully convinced that if Todd's car had good drag radials on it rather than half-dead stock NA wheels and tires (225-45-16) it would have easily run in the mid/upper 12's. It was simply spinning the wheels all through 1st and 2nd gear.

So, can an NA be turbo'd? You bet your ***. Is it worth it? I'll let you decide....

p.s. I do not have the dyno sheet from the peak stable run, Todd has that and I'm sure it will be up soon for everyone to see. Its not peaky at all either, it has a VERY wide powerband which begins at 4300RPM and stays at this 340HP level all the way to the rev limiter. IT has a broader powerband than any TT I have seen.


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