How does friction decrease pressure? Friction creates heat which would increase pressure.

 

Friction increases volume, which increases pressure at the restriction.
After the restriction, the pressure is lower.
However, as noted earlier, a centrifugal "compressor" doesn't actually compress air - it accelerates it. This should be compared to a positive-displacement compressor that actually creates pressure as it moves air.

Honestly, I am not really the best person to be discussing this stuff because I don't always have the best immediate grasp of all the math.
I am usually operating on net experience in this area for which I then find the corresponding math.

 

Ok, thanks MM. I guess I am close enough on the principles. I just wanted to make sure I wasn't missing something weird.... waiting for my books now. YESSSSSS.

 

heat | volume | pressure

Change any one and the other two are affected.
Hold one constant and change a second, the third takes up all the slack.

A turbo is interesting because it affects density through inertia, rather than compression.

 

General Gas Law to the rescue!!!

Update from Wiki:

In an idealized sense, the dynamic compressor achieves a pressure rise by adding kinetic-energy/velocity to a continuous flow of fluid through the rotor or impeller. This kinetic energy is then converted to an increase in static pressure by slowing the flow through a diffuser.

So it does use speed... but the diffuser "rams" the kinetic air into a fixed volume slowing it down and creating a higher PSI. I think.

 

^^ Yes. Exactly.

 

I am hooked! When I starting thinking about this stuff in terms of diving, it clicked. I have been reading all day about FI, engine compression, timing, EFI etc. I always knew how they worked but nothing about tuning. This stuff is cool. I no longer hate new EFI cars.

 

At least you don't have to get into bubble modeling with the car

 

Wanted to install Greddy into my RX-8, but would not be able to drive it on the high ways of Cali. if I did. Not if I wanted to keep the registration up. Found out the Greddy Turbo is nto street legal in CAli.!!!

 

^^ Great first post, Einstein.
Since when does everyone in Cali mod their car on CARB rules?

 

I took a class in college on turbo machinery and, frankly, the involved math was not as interesting as I would of hoped. I'd rather rely on experimentally derived compressor maps and just work out the thermodynamics math.

 

Based on your fixes, can it be assumed that the kit can now work reliably, without any further modification? I understand that nothing beats a custom tune, but are these 3 fixes the "silver bullet" to the troubles with this kit? And in doing so making it work how it was originally supposed to, as someone would want it, as a daily use vehicle?

 

No. Never make any assumption of the sort.
The fixes get the parts all working together correctly. However, there is still the need for a proper tuning session.
If you leave every other aspect of the kit alone, it will probably be 90% good.

 

Awesome, thanks for the help and clarification

 

Ok, here goes. I've been reading around trying to help a friend out who just bought a 2004 rx8 with greddy kit installed. It is the older version with e-manage blue. All my knowledge is basically honda related but I love anything boosted so I am helping him out (and I get to drive a rx8 around for a bit ). I really like the rx8 but $$$ won't let me get one. Anyway, the car accelerates very well progresively when starting from 1st gear and shifting all the way to way thru with no problem. AFR's look really good. The problem (like many had before him) is when you are cruising and slam on the pedal. When you hit WOT while cruising it will boost but the afrs go extremely lean (16). I read fix #3 and hope thats will fix it but I would like to know if the p2 wire cut applies to the e-manage blue, ultimate or both. Sorry if the answer is in my face, I've been reading thru but there is soooo much info its hard to keep track. I've seen many go from e-blue to ultimate to inter x. I downloaded the e-mamage update 1.49 and was going to try one of the maps I downloaded here but then read about the greddy ugrade which seems to be more of a fix then an upgrade. Should he also get the upgrade and do the 3 fixes. The real lean condition is what is the real concern. I can fine tune the maps for him but the lean condition seems to be problems with the way it utilizes all the maps. Thanks in advance.

 

does it go to 16 afr and stay there, or 16 for a moment before dropping down?

 

Actually I'm not too sure. I think it stays at 16. I'm not sure for 2 reasons: 1- He has a autometer wideband so I'm not sure if it reads any higher ....... I will verify that. 2- When it hits 16 and we can hear the pinging or detonation I tell him to back off.... I would hate to be the guy that helped him break his motor. Is there anythng else I should check?

Thanks!

 

The re-wiring of the P2s will work with both, but I highly suggest the e-manage Ultimate update for the system.
There are just too many variable that I am no longer familiar with on the blue to offer advice.

 

Ok. so the best bet is: get the greddy upgrade (e-ultimate, blocking plate etc....) use Tims380SeveredInjectorMap13.zip and do the 3 fixes.....fine tune from there.

 

You can download a newer MAP from my site.
Don't use the blocking plate and switch the injector wiring to the format outlined in the "fixes".
The Ultimate comes wired with the sub-injector controller hooked up to the secondary injectors, not the third-stage "primary 2" injectors.
While this will work, it isn't compatible with any of the newer MAPs and probably isn't the best way to wire the thing.

 

Thanks. I went to your site and it is mad cool. I spoke with my friend and he said I had the go ahead to order the upgrade but he also said he wants to up the boost a bit more (a couple of pounds, maybe 3-4). With the what was mentioned before is there anything that should be changed or added for a couple more pounds of boost? I'm going to make sure he figures out how far he wants to go with it because if he then wants a bit more then he might aswell order injectors while he's at it. He already has a 255 fuel pump installed.

 

You are not going to go past 8 or 9 PSI on the original injectors without problems.

You can install the secondaries from a 4-port (automatic) RX-8 to give you enough headroom to go into the 11 PSI range on that turbo.

 

I've seen similar scenario, I bought once a soft hose and every time it would boost it went lean then it would run right. I guess the hose contracted and when it boosted it expanded and readings weren't precise.

 

so does this only applies to the ones who're using the e-management? or also applies to people who are running the interceptor too?

 

Obviously, only #2 applies to the Int-X, which needs fixes of its own to be street-friendly.