patrick_andraste

maybe why they use two of them on the skyline, even when converting to a single turbo

Richard Paul

iTrader: (5)

Alright here's a hint. We just put a new SC on the car with no aftermarket controls on it. Therefore we have a very large pulley up top for min boost. 140mm vs 100mm that will be used standard. I went and put a full tank of 101 in it and ran some tests. I should say test...... The first try had detonation at about ~8000 and ~4+ psi. I'm going to try it again and get better numbers. More exact that is.

That I assume ends the above argument.

We have a new ECU and that will be next.

Jedi54

iTrader: (7)

Sweet RP, I might have to swing by the shop again some time soon. Let me know if you ever want some company on a weekend and I'll bring the cold beers.

ModMech

RP and Hymee,

Don' get me wrong, I an SURE you fellas know what it needs. I was just thinking on "paper" as it were.

I did not know that the RX8 went to open loop so early or easily, other vehicles that I am familiar with do not. That itself ends the discussion, no to mention RPs tests.

Aseras

thanks for the update richard...

while the stock pcm maf idea might work on a piston engine, rotary just eat so much air there's no way it's going to handle a significant increase in volume like fi on a rotary will produce.

mind if I ask what you think the cfm is where it was detonating? then you can get back to work. I expect a AFSC for my birthday on Oct 2nd

dsmdriver

iTrader: (3)

ModMech, what cars use the O2 at WOT? The 8 acts just like all other cars I know- get up around 50% power or get the RPM's up and they jump to pre-calculated lookup tables with the LTFT as the only adjuster.

Just interested to know what cars are out there that self tune deeper intop the power output.

seikx8

Here is the MAF voltage to g/s scale graph that represented by 48 cells data referenced by the OEM flash image. The max value is 4.68v -> 365 g/s.

The load axis is another story, for FI application to work properly they will need to be rescaled. Currently I think it's only go up to 120% load, so low boost (2-3psi) may be ok in stock form.

zoom44

i know damon was talkign to me about a map they had for FI(an SC i think) that went up to 200 load. or was it VE? anyway they had a good map. he's not at RB anymore i hear..

seik did you find that in the flash? excellent work!

ModMech

Lots of Ford stuff is closed loop to 70%-80% load. The deceptive part is this can happen at 1/3 throttle, or not. It depends on the RPM involved.

I do not think I said anything did use an O2 at WOT, in fact I think I at least implied that you CANNOT use an O2 at WOT, or even anything close to it because of the super narrow range it can read in. A WB however, can "read" from 11.5ish to 16:1 AFRs, so it is possible to use them even at WOT.

rotarygod

Chevy has an interesting system in place with the LS1 ecu's that still allows the car to run well if the MAF shorts out. Some of those guys simulate a shorted out MAF to the ecu and suddenly the car runs in speed density mode. It's not as easy as just unplugging the MAF altogether but it might be as easy as shorting out 2 wires or just cutting one of them. I'm not quite sure. I've never seen this tried on any other car and not even until the Camaro guys were mentioning it. It would be interesting to see if this works on other ecu's or if it is unique to only those. They do get a CEL but that's understandable. Whether it would work on these cars or not, at the very least it is curious.

Hymee

iTrader: (1)

Yep - it is quite common to get a MAF-less tune in an LS1, and without a cell - but they have a slight advantage - the LS1 also has a MAP sensor. The RX-8 doesn't

This Makes it easier to tune for boost on an LS1, an perhaps a little more of a challange on the '8.

Cheers,
Hymee.

rotarygod

Yeah a map sensor would make a difference.

MazdaManiac

iTrader: (3)

Forgive my ignorance on this Richard, but wasn't the Latham supercharger designed and built by Norman Latham in 1955?

If you are Latham, that would make you at least 70 years old! (Which is awesome, but unexpected.)

Japan8

Jeff... you're going to get flamed for that one. It was mentioned MUCH earlier in the thread... richard bought the company and patent years ago (if I am remembering this right).

Richard Paul

iTrader: (5)

HaHa, You're both sorta right. Norm Latham designed and built the first axial flow supercharger in 1956 and sold them until 1965. I bought the company in 1982. I then discovered the flaws in the design and gave up the project. Not being the type that likes to fail I redesigned and retooled a new "Latham" in '83.

The "new" one had aerodynamic blades and inlet, outlets. New belt design and modern carbs. Norm was 76 when I first called him on the phone in '82. He was a clever machinest but knew little of airflow. Still he built the best blower of the time by far. It just cost way more then anything else. If you put 354 sheet metal blades into rings by hand you can understand why.

Gm used them alot on their show cars and even the Mako Shark had one. Several GM execs had them on their fishing boats.

I had the same problem of cost and only built them for 8 years until I designed the billet method of producing them. That was even more expensive and only sold to car companys and airplane builders. A few compressors for odd uses were built.

It wasn't until 1998 that this new method of construction was devised and it is possable to build them at reasonable costs. It all has to do with CAD and CNC.

I kept the name Latham in the '80's because I promised the old man that I would. Now there are not many people who remember the name so I dropped it.

So no I'm not that old Jeff. Althogh Katwoman is visiting and last night about 2am I felt like I was 70.

MazdaManiac

iTrader: (3)

As long as you keep hitting it, it doesn't matter how you feel after!

Red Devil

I remember hearing about Latham SCs from time to time growing up. They were kind of mythical, they were supposed to be the best thing since sliced bread, but they'd only been rarely seen, if even that.

r0tor

iTrader: (1)

the thing i've always wanted to ask richard is how he gets around the problem of compressor surges with this type of compressor...

I work with large axial flow compressors in the power industry and they are very grumpy when it comes to sudden speed and load changes - even with elaborate blowoff systems

but then again... mine are a bit bigger and have 17 stages (similar to this guy but a bit bigger)

Richard Paul

iTrader: (5)

You answered part of the question yourself. I don't ask high loads per section as is common in commercial usage. Of course that is only part of the answer, the rest of the stuff is kinda what my work has been for 20 years. In SC use it must run from idle up to redline, in jet turbine usage the max is 65% of the range.

You can understand that I can't tell you how it's done. I can tell you that I don't know everything about it and sometimes run into designs that have stalls or surges somewhere in the band of operation. In fact one of the rx8 units along the way had flaws because we made a dimension change without going through a complete analysis of the aero characteristics.

It's tricky, nice to see someone appreciates that.

punishr

I don't think that is going to fit in the 8's engine bay!!!!!!!!!!

r0tor

iTrader: (1)

but if it did, it flows enough to support 162,263hp at 3600 rpms

Wing5

.....O.< [twitch]

Aseras

yeah and .0000042 mpg...

Brettus

iTrader: (2)

with some bolt ons you could improve that !

crimson-rain

... dude that wing I got from autozone should help with the downforce.