GZE Questions

**Ben Wilson** · 01-05-2006, 03:43 PM

It sucks to remove the SC with a standard inlet manifold. Mine is a lot worse....

**nick.parker** · 01-05-2006, 07:54 PM

I gained 1-1.5psi, and the inlet temps are pretty good, so I assume there was a corresponding power increase.

I observed the same thing (higher MAP) and though manifold pressure was higher, torque was lower. The conditions were injecting before the SC, 18psi, 12:1 AFR probably 24 degree ignition advance...even with more ignition advance still (maybe I didn't go far enough) it didn't improve torque to the point it was without the mist.

Ben , Have you not dyno tested on vs off then? Can you run your car with it off? I am interested to know if the car has more power, since I have not achieved 'sucess' with water injection yet.

I think I will ask on the aquamist forums.

Cheers, Nick

**Ben Wilson** · 02-05-2006, 08:13 AM

Interesting, I've never tried it without. If the weather is decent this weekend (no heater). I might give it a go.

**rick q** · 02-05-2006, 09:23 AM

re the water injection, I would have thought from a thermodynamic viewpoint, adding the mist after the s/c (when temp is highest) would give the greatest gain. The temperatures are not at a point to turn the water to steam, but the latent heat of vapourisation (as the water droplets convert to vapour) should give the greatest cooling effect - like an evaporative cooler.

Since the process is one of constant pressure (because the s/c is constantly pumping into the sytem), the result would be a lower charge temperature into the intercooler - and hence even lower into the engine. Denser charge = more oxygen = more power. The limit to the amount of water to add would be where moisture starts condensing out of the inlet air stream as it cools - then you'd lose power in big chunks.

I dug out my old text books over the weekend to do the maths - but it's been 30 years since I graduated (mech engineer), and the brain fade was tragic. I'll have another go this week.

On the original question, is it worth the effort the change from the standard manifold to the smallport.

And .. is there anyone on the forum with a GZE near the Sunshine Coast so I can have a look at some of the details.

**Ben Wilson** · 02-05-2006, 09:45 AM

Rick - From my testing, the entire inlet system in a ZE is very balanced. Every component seems to flow about the same. With the standard inlet manifold, my car produced 114kW, with my new manifold, aftermarket ECU, water injection etc it produced 130kW. Not a big difference.

From my calculations, it looks like my throttle body and 2" inlet piping are the restriction now. I'm working on upgrading it all to 2 1/2" in the future.

Basically what I'm trying to say is that no one part of a ZE inlet system is a major problem, it's either all horrible, or fairly well designed depending on your point of view

Just changing the manifold will help a little and if it's easier from a packaging point of view, go for it.

**takai** · 02-05-2006, 10:20 AM

Its simply fairly well designed for a specific application. For power outputs higher than that application its is simply horrible.

Is that what you were trying to say Ben?

**nick.parker** · 02-05-2006, 10:57 AM

Denser charge = more oxygen = more power.

Yep cant argue that. BUT in context to the SC MR2, for a constant inlet temp (to the SC) the temperature has not much to do with air density at the outlet of the SC, only the pressure because the SC always moves the same amount of air. Yes with hotter air the pressure gauge will read a bit higher, but density is the same since the same amount of air got stuffed into the manifold.

What you are talking about is more applicable to turbo setup where you have a boost setpoint, in this case density matters since hotter air at a fixed pressure will have less density than colder.

Cheers, Nick.

**Ben Wilson** · 02-05-2006, 11:18 AM

Originally Posted by takai

Its simply fairly well designed for a specific application. For power outputs higher than that application its is simply horrible.

Yeah, it's also well balanced, there is no one choke point on the system.

**TooF** · 02-05-2006, 11:52 AM

Originally Posted by rick q

re the water injection, I would have thought from a thermodynamic viewpoint, adding the mist after the s/c (when temp is highest) would give the greatest gain. The temperatures are not at a point to turn the water to steam, but the latent heat of vapourisation (as the water droplets convert to vapour) should give the greatest cooling effect - like an evaporative cooler.

Since the process is one of constant pressure (because the s/c is constantly pumping into the sytem), the result would be a lower charge temperature into the intercooler - and hence even lower into the engine. Denser charge = more oxygen = more power. The limit to the amount of water to add would be where moisture starts condensing out of the inlet air stream as it cools - then you'd lose power in big chunks.

I dug out my old text books over the weekend to do the maths - but it's been 30 years since I graduated (mech engineer), and the brain fade was tragic. I'll have another go this week.

On the original question, is it worth the effort the change from the standard manifold to the smallport.

And .. is there anyone on the forum with a GZE near the Sunshine Coast so I can have a look at some of the details.

keep in mind the other nice thing about injecting water pre supercharger whilst this dosent reduce temps as much it does also help to seal between the lobes of the charger and hence improves SC performance....

at least thats my understanding.... someone correct me if im wrong