jcsbanks

I think and log everything in metric...

I only hold 280kPa from 2600-5000 RPM in top gear in cold weather (later than 2600 in lower gears!), which logs at about 280 load. I may peak at 290kPa, if it is higher I reduce the duty as I feel guilty about the conrods due to high cylinder pressures. I would run more on the same fuel in cold weather if I had the conrods changed. It is common to run over 2 bar (300kPa absolute, 29 PSI boost) of boost on 99 RON in the UK with uprated conrods. When I've spiked higher than my intended boost the car has obviously more torque, I just worry about the conrods.

So 280kPa or 280 load is about 26 PSI on my setup.

l2r99gst

iTrader: (2)

Thanks. I was questioning more about the actual 2-byte load rather than the kpa of boost. From Bez's disassembly, he has shown that load is actually a mass airflow/rev, which I have assumed from the beginning. So load can be different at the same boost levels, with changing temperature, altitude, VE, etc.

Thanks for the info, though.


Eric

jcsbanks

I find astonishing consistency between load and MAP.

Perhaps that is because the altitude and temperature variations are extremely low compared with much of the US?

jcsbanks

Referring back to my original 2 byte load vs MAP plots:

https://www.evolutionm.net/forums/sh...light=load+map

I now run more boost that I used to, but whenever I plot load and MAP it looks more or less the same whereby the midrange load is virtually always within 10 of the MAP in kPa.

l2r99gst

iTrader: (2)

That may very well be. I can see temps from well below 0 F in the winter to 100F in the summer. Mass airflow/rev change quite a bit in the different temps.

I'm going to post up a thread today or tomorrow to estimate boost from load, taking into account temperature to see how well it holds true for various logs from people here.


Eric

jcsbanks

255 to 311 Kelvin. So that alone gives a 22% change in air density! Sounds like a walk in freezer with an elevator down to hell in the corner, with the disadvantage that you don't control when the elevator breaks down

In terms of actual inlet manifold air temp once the car is warmed up so that I can use full boost I'm probably about 285 to 305 Kelvin - only 7% range at most on my typical daily drive. Got to love an island climate

mplspilot

iTrader: (7)

I dunno if it's any help but i have 28 psi tapering to 21.5 and i hit about 305 load.
Off-white line is load
Grey is boost



This was with HKS 272, i think i hit more load with 280's now.

Nuked

iTrader: (9)

At 28psi spike I have hit around 310.

SQ

JohnBradley

iTrader: (30)

Stock turbos at around 25.5-26psi with cams seem to generally hit 290ish for load (IX's anyway) on pump gas. Timing numbers are about the same as Tkklemann with the AFR's at 11.5:1 (on 93 octane). I may have posted it in this thread but since I am lazy and wont look, I hit 285 on the stocker at 25ish psi, 6* of timing and just a 280* HKS exhaust cam. I had all the piping but that was through the stock airbox and intercooler.

The only reason I had asked about your load was the fact that it was holding 23 or more so high which I have only seen once or twice from stock turbo cars.

edit- I did look and this another thread by the same name but I posted it now.

dudical26

iTrader: (17)

Here is a log where I scaled the boost x10 to match the load. As you suggest boost follows load very closely.

Now if I could only get my boost curve to be smoother.

C6C6CH3vo

iTrader: (9)

Keep in mind the valuable fact that your setup is a totally different beast. Likely your volume/psi is much greater due to the MIVEC enhanced dynamic compression in addition to the larger compressors increased output. Static boost is less because the engine is consuming more air per unit of time.

Comparing apples to oranges, but I will assume the airflow/boost differences will show this.

esevo

iTrader: (11)

I "spike" to 27.5 PSI in 4th on 91 pump + meth/water. 4* timing at peak TQ and 12.0-12.4 AFR'S consistent. NO knock.

I have the wastegate "mod" with the spring to hold more boost till redline. I hold about 24 psi till 7500 rpm (4th gear). No way to log it as of now, just going off the gauge.

I have an Aquamist 2d system with 65% water and 35% meth.

Mods are:
Apexi filter
Hallman Mbc
IC Pipes
TBE
02 housing
Water/meth
Walbro.
Most recent dyno (more timing)



This was a couple weeks ago (Afrs are tail pipe reading) Notice how hot it is lol!!! 3rd gear pull.

RazorLab

iTrader: (8)

You guys that run meth and 91 should really put 91 octane + METH when you first say what octane you are on instead of saying it half way down the page.

esevo

iTrader: (11)

^^^ Fixed

RazorLab

iTrader: (8)

Thanks, that has always irked me for some reason.