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Made it to the dyno


1 fast z

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SDS datalogging is very basic. You can only record AFR's for the RPM cells. It's handy in a pinch, but obviously, the more parameters you can log the better. I hooked up the EFI sensors to my TechEdge wideband 02 meter for logging. It has 3 user inputs + RPM and 3 EGT inputs (I wasn't able to get those to work though)

 

Nigel

'73 240ZT

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Its really not needed to datalog with NA cars. I dont use it on my silver car. But with around 500 WHP, things go by REALLY fast, and you cant watch. My car will go from 4k, to 8k REAL quick, and I cant monitor my WB autometer guage that fast. So I datalog. MS gets about 18 parameters, when it datalogs. SDS is just like what SDS stands for SIMPLE digital systems.

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But with around 500 WHP, things go by REALLY fast, and you cant watch. My car will go from 4k, to 8k REAL quick, and I cant monitor my WB autometer guage that fast. So I datalog.

 

Where did I hear that mentioned in the past?:D

 

Unless you have the ability to really load the engine up so it takes TIME to accelerate through the load cells, datalogging is the only real option to see what is going on with the car. Even with that 38% grade, it's still pretty quick...it just gives us more cells in the log table to evaluate the situation instead of grabbing just a few cells and trying to make a quick decisio.

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Ok, so the dyno place sent me the dyno graph, here it is. Its shown in 10 MPH increments, and that is exactly 500 RPM in 4th gear with a 245 45 17 tire and a 3.7 gear.

 

 

Source: http://www.bandmzcars.com/dyno.html

 

 

So :

 

50=2500

60=3000

70=3500

80=4000

90=4500

100=5000

110=5500

120=6000

130=6500

140=7000

150=7500

160=8000

 

This is with STOCK cams by the way.

 

new_graph-752x565.png

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Well, to start, the stock turbine housings are a little too big as compared to the turbine wheel. The different aspect housings usually force a closer fit, and more of you exhaust is doing the work, resulting in lower RPM spooling. The downside is the increased backpressure.

 

Usually, the biggest increases are seen from using a larger compressor wheel and housing. There is both a point of diminishing returns, and a point of NO return, where you just burn up the turbine wheel. Both of these points happen when you go with too big a compressor, or too small of a turbine.

 

Although I've not ever had a ZX turbo apart, I have built several turbocharger based jet engines, which require more efficient turbos to get any kind of decent power, so I'd imagine that while a full on jet engine turbo wouldn't work well, a larger compressor side and a tighter turbine housing would have better flow, and higher pressures at lower turbine RPM. This is a little easier on turbo bearings, which, by the way, need to be addressed. Good thrust bearings are a must, and the ZX stock turbo bearings aren't that great. While adequete, more recent model turbo would be better in this respect (Oh really, you think? :P)

 

With the better matched housing and turbine, a better thrust bearing, and a larger compressor wheel/housing, you could very easily make a 50hp jump.

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Explain how the turbos are not efficiant, I am curious. Again, I dont know much about turbos themselves, as far as ratios etc.

Biggest issue I take with the explanation above is that it is applicable ONLY to a single turbo application.

 

When you are using TWO ZX Turbos on the same engine that only had one to begin with 'restriction on the exhaust side' ceases to be a factor.

 

Actually, you have an Exhaust A/R closer to 1.20 with what you have.

 

I think the JDM .43 A/R exhaust turbines reworked with a slightly larger turbine exhaust exit path, as well as using a slightly better Compressor Wheel (more efficient at 15 psi for example, and provinding much more flow) will net better spool characteristics, as well as better lower rpm performance.

 

As it sits, you are using only 1500CC's to turn each turbine, and I believe it will be a simple matter to control wastegating on the stock turbo wastegate flappers well up in the HP range.

 

 

Interesting the power peak is at 6500. Some cam timing may help on that. You installed adjustable cam sprockets, right?

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I still don't think anyone has looked at a 60 trim map X 2 and at the pressure ratio he is running.

Is this the map you are looking for?

Fig4.gif

 

17psi of boost and 500hp would put you near the following:

pressure ratio ~ 2.2

airflow per turbo ~ 34 lb/min

 

25psi boost and 600hp:

pressure ratio ~ 2.7

airflow per turbo ~ 41 lb/min

 

My assumptions for the airflow were 15% drivetrain loss, and 1.5 SCFM of airflow per HP, with air density of 0.0765 lb/ft²

 

So ASSuming that this is the correct map and that I did my math correctly, the numbers that 1fastZ put down are right at the ragged edge of the compressor map for those turbos.

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Ya, they are at the edge but still atleast 65% at peak HP, not through most of the power band. Not the best but still in on the map. 60-1's and GT35r's have made 500rwhp many times and only flow around 60lbs. Garrett rates there GT35r up to 600hp with about 5lbs/min less airflow. For less than 20 psi I wouldn't change them.

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Man I wish I could just download the knowledge of some of you guys into my mind. It astounds me how much some of you guys know.

 

 

hey man, every time you come on here and read a post until you're pretty sure you understand it, only then have you downloaded every byte of data =)

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Ya, they are at the edge but still atleast 65% at peak HP, not through most of the power band. Not the best but still in on the map. 60-1's and GT35r's have made 500rwhp many times and only flow around 60lbs. Garrett rates there GT35r up to 600hp with about 5lbs/min less airflow. For less than 20 psi I wouldn't change them.

 

For 500rwhp, I agree. For 600rwhp, it just kinda looks like you're going to have to lean on those turbos pretty hard, and I think that's where the efficiency comments came from.

Probably not out of the realm of possibility though - how much power have people been able to put down with the stock (single) turbos? I'm pretty sure I've heard of high 200's, anyway...

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