You can; it just becomes inefficient (aka HOT) as you move to the right side of the compressor map.

Boost is important for compressors since that is what they do; flow is for motors.

The turbo may be able to push out seven zillion HP at 2 PSI; but if the motor can't flow that much air it is irrelevant - and vice versa. I may be explaining this whole thing poorly.... I guess the weaker link in the chain is what limits power might be an easier way to look at it.

 

plot thickens.

 

I bet you will reach your goal of close to 400 rwhp...Are you still shooting for 400 rwhp on pump? If all else fails just add methanol injection....

 

you need to be aware that 10psi at the manifold is not 10psi at the turbo (which is what is relevant here) .
In my case that can mean a 4-5psi difference ..............

 

I think I've got it, you've moved to Antarctica without telling anyone!

I really wish we didn't have to play super secret decoder ring club and you would actually be up front about things *sigh*

Judging by what you're saying, you've done something with the compressor wheel and you're running some sort of charge cooling.

It'd be nice to actually know what the heck you're doing with your RX-8.

But of course, I know you'll just call me an idiot and tell me that you don't need to be forthcoming with all of your secrets. I'm just a curious soul and would like to know, that's all.

 

Which I am aware of, I took a 2 PSI drop into account when I did my calculations... give me a little credit, I'm not *that* clueless.

Or maybe I am, perhaps I should just give up

 

I will almost def add meth/water at some point for safety; purely for ego it would be cool to get close on pump gas and no meth.... but we'll see.

 

Ah HAAAAAAAA ! you sly bastard !!!!!!

 

Well, 8600 rpm, 103% normalized VE, ambient intake at an intake pressure ratio of 1.73 can push 400 grams/second. Now on the chart you'd probably have a P/R of a little more than 1.8 adding a little pressure for system losses. The key then is intake temp. So I assume MMs turbo is a little more efficient at this flow rate and he is able to keep his intake temps very low (would be extremely low for Arizona were this the summer).

 

The PR is going to be higher; once you account for the Density Ratio and Pressure drop across the system to get say 10 PSI at the intake; which puts the PR into a higher and in this case more efficient island by and large.

 

sorry man - I do see a lot of people talk about this and nine times out of ten I'm pretty sure they only look at manifold pressure and have never measured what the turbo actually produces ....

10psi at the UIM translates to a PR of more like 2.0 (for greddy setups anyway) .

 

Higher Pr = higher efficiency island

 

Even with the PR being different, I only see that moving the point on the Y axis...

Unless I'm being completely obtuse, that shouldn't change the quantity of air... any point plotted along 50-53 lb/min range is outside the island of the compressor completely.

Now, obviously the MM Upgrade is not a stock GT3071R, but am I missing the fact that the compressor map *as I posted* should NOT flow 400 g/s of air?

 

quite correct .

Maybe he shoehorned a 3076 in there without telling anyone - it would need to be that size to flow the air he is claiming .....

 

.............

 

Now that makes more sense...

At least I know I'm not *completely* off base now. One thing that this discussion has made me realize is that I need to start thinking in terms of the full system, not just what comes out the outlet of the compressor.

Anyway, back on thread topic - congrats on the awesome engine Kane. I'm looking forward to seeing this beastie in person soon. VA isn't that far away, and to get a ride in the (Phantom) Blue Beast, I'll make the drive!

 

Keep on it.

B

 

If a 3076 wheel were shoehorned in there without anyone knowing it, it is still no longer a 3071 which makes any argument about a 3071 moot.

 

well according to this post MM has a GT3076R

https://www.rx8club.com/showpost.php...40&postcount=3

 

I don't know why, but I like this picture.





What were you saying?

 

Sorry, I think i meant to post this picture.

 

/\LOL


How about I just ask a direct question

MM , do you have a 3076 wheel in your turbo ?

 

A GT3071 at 10 psi is nowhere near the same as a GT3076 at 13 psi and if that wheel is somehow shoehorned into the GT3071 housing, it is still a GT3076.

 

Easy, I've completely lost track of what this thread was about thanks to you

 

God, that pic is pure win