no surprise with the smaller divided housing, how is the load holding up at higher rpms is the question

From recent logs on 4psi , it climbs to 170ish.

But forwhatever reason the car doesnt like to go past 7400rpm. Standing on the throttle it goes 7300,7400,7350, 7370.
Maybe to rich, wo2 is pegged, lc,1 reads 11.1.

Or maybe a broken intermitten plug wire, i have the bhr kit, just need to test the wires

Am I missing something here? 1000rpm difference from JUST a turbine housing swap? That is impossible.

FYI guys a .84 P trim turbine housing is about the same volute as a 1.06 GT35R( T3 or T4)

I thought going from an open 1.0 AR to a divided 0.84 AR was generally considered to be a big change, but will defer to your expertise

1.00 divided to .84 divided, on a p-trim.




fine call me a liar.....

Thanks for the clarification

I'm not calling you a liar, its just that something else was also changed( outside air temps makes a big difference), or you are basing this off just driving conditions.

I have done back to backs on many vehicles, piston and rotary. To get a 1000rpm jump takes going from a 1.19-1.32 down to a .84/.81.

I wanted to share this

I have found it increasingly annoying that my stock wideband does not seem register in WOT situations, its placed 3 inches from the turbo inlet. this makes it challenging for tuning, so

I decided to install my second wideband in the downpipe about 10 inches away from my turbo, my Friend who tunes his RX-7 tunes this way so I thought I would try it aswell.

my hypothesis was that the stock wideband becomes saturated or something due to the extreme heat and pressure present before the turbo.

after the install was complete a test run was in order, in 3rd gear WOT, the stock wideband read 10.9 from the AP unchanged for the entire run.
the secondary wideband however read, 11.5 and a apv lean spike of 12.4

so it seems my hypothesis was correct for my situation.

I have added more fuel to my tables since then......

Well, yeah - you can't put it before the turbo.
I thought that was pretty well understood.

I don't think I've ever seen anyone even try that.

how do you know which is correct and which is not?

if your hypothesis is actually correct you might try installing a high temp isolator fitting instead to prove it out

I am going to pretend that you forgot this is a top mount and leave it at that.......

it doesn't matter, he just told you straight out, I was going to lead you around the long way to demonstrate how your assessment and logic is flawed, which is all too common around here

the O2 sensor will not read properly in a high pressure system, this is why it has to be installed after the turbo


.

What does that have to do with it?

All of the proper top-mount systems put the O2 sensor in the DP, just after the turbo.

yikes, mounted the o2 pre turbo??? That needs moving.

I'm not certain that this has anything to do with it - the temperatures are simply too high and the gas velocity too low for the pump to make its own reference. The heater just goes out of range.

Now, several of the early top-mount systems put the O2 sensor too far away - essentially in the physical stock location, which is too great a distance (in terms of piping) from the exhaust ports.
Another salient point is that the sensor, should the WG be VTA, must be unaffected by the gaping hole in the gas flow that this causes.

You can address the temp, especially since the top mount pre-turbo position is not much different than an NA manifold. That piece of info comes from someone smarter and more experienced than me and likely anyone else on this forum. Believe it or not, your choice.

The distance/position isn't really relevant since the gas is doing something totally different. Port-to-inlet EGTs are WAY over N/A EGTs and the gas velocity is low.
The whitepaper on the Denso WB puts its thermal saturation point at 2000°F. It was essentially designed to work at 1700°F.

you would argue with GOD about the creation of the universe if you had the chance ... next time do your homework before you shoot your mouth off. Temperature matters, but you have nothing to indicate what the actual temp is or that the same thing still applies when temps are lower like in a piston engine or alternate fuel rotary ...

Were there such an entity, you are correct.

I did pre turbo in the beginning to avoid the lag, and at the time sfr and turblown had the sensers preturbo. They where tuned this way, and so was my car (by mm) and I dont ever recalling you telling me about the sensor position during our tuning session.

In any case its fixed.

ok question is where the hell is mine supposed to be?

:uhh: :Eyecrazy: :squint: :)

lol my thoughts exactly lmfao

Beside the Maf right after the BOV

yes!

you will always find some point to dodge over regardless, just as you did

So I tried to do some more research on the matter but can't find much about it.

to bring some folks up to speed, I now have a .84 T4 housing that spools sooner, and have gone to a VTA wastegate,

my issue is I am reaching the limit of the maf at only 9psi, does this sound right or is something wrong with my maf

4.88 volts is 403g/s
my last wot was at 400g/s and 205% calculated load

i see around 350g/s peak at 7500rpm at 9psi but with a smaller turbo . I guess what you are seeing is possible . Hop on the dyno - if you make 350 whp ish your maf is correct .

Interesting, well yeah I guess I will get the tune a little more in line then put her on the dyno
At 9psi she feels and acts like 11psi last time.

I guess a 4" maf maybe next?

Are you still having problems with timing getting pulled?

yeah but I am getting that under control, I am pretty sure its the screamer pipe triggering the knock system to activate

Your numbers mirror my exact experience. RWHP numbers will only match maf numbers if the tune is correct. You can still see high maf numbers and not make much power if the air is not being burned correctly.

How have you confirmed timing is being retarded? That has been my theory with the cobb units for quite some time. I have seen it on ones without VTA too. Bring a timing light next time you go to dyno and verify actual numbers.

Thank you for posting that! Its a relief!
I am still working on the burning the air better though ;)

I have been watching the lead timing advance in my logs,the results are always my commanded timing minus my knock retard max value. This typically starts when the wastegate opens, and stops right at knock retard max rpm value. I beleive the system is reporting knock but cobb does not report it. This theory is in large part due to oltmanns research on the matter, and what I have observed

Last time I was on the dyno a mere 2 degree difference in ignition advance only was worth 15% increase in power! Tuning these cars in person on the dyno is what really makes the difference in power..

what afrs do you shoot for?

seems unlikely - sure there wasn't something else going on as well ?

Crazy log I got tonight

really shows some interesting stuff

5v = 438g/s for me

WTF ? A 170g/s jump in 0.2 seconds !!!!!! does not seem possible . Did hit 'warp drive' at that point ?

he also got a 10 mph in second gear increase in about 1 sec!

Forgot to mention it was raining ;)

Yes it was raining, so perhaps that hesitation wasn't a hicup but rather the tires broke loose when the apv opened.

after that test I got a p0203, high maf input, so my guess is it got wet again, so frustrating I can't drive the car in wet weather that log was at 5 or 6psi or so. I turned my ebc off because with it on I was doing 9psi and my calc load went straight to 212, I don't know if thats the limit of the maf or perhaps the sensor was already wet.

put it does show two other things for me,

1. some how the MAF was able to keep reading G/S past my maf scale. because 5v = 438g/s thats it, so the computer must have figured out what it would be at say 6volts or so, Really wish I was logging maf volts.

2. I can set the multipliers to exceed 200% load, and scale my fuel and timing (currently at 2.1) and it keeps sending the right info, no reversion to some mystery stock timing map.

on a side not the butt dyno enjoys less split....

Interesting stuff . However , at 9psi you should not be seeing load that high . Plus those 500+g/s readings have to be erroneous . I think your maf readings are playing tricks on you .

Yes I think so too, it was 46 degree intake temp so that doesn't help

just not sure what to do about the damn MAF

My guess is you have some kind of turbulance effect going on - possibly due to being close to a bend or swirl from the turbo intake itself ?

right now its the filter, through a mesh, then a 6"x3.5" MAF tube, to a 90 degree 3.5' tube,

I am beginning to think the element has lost its resistance so its taking more current to to keep it at the same temperature.

I say temperature because The wire's electrical resistance increases as the wire’s temperature increases, which limits electrical current flowing through the circuit. When air flows past the wire, the wire cools, decreasing its resistance, which in turn allows more current to flow through the circuit. As more current flows, the wire’s temperature increases until the resistance reaches equilibrium again. The amount of current required to maintain the wire’s temperature is proportional to the mass of air flowing past the wire. The integrated electronic circuit converts the measurement of current into a voltage signal which is sent to the ECU.

and after the 3.5" bend is the turbo right ? With no screen or honeycomb in between ?

not its straight, goes down to 3" then 90" into turbo, no extra honeycombs

so the total system is a U

this is an old picture and the silverpipe right after the filter and straight is now a 3.5"
http://farm8.staticflickr.com/7002/6...0befc56c_b.jpg


and for anyone new I updated the First post with 2 pictures and cleaned up the thread, lots of dead pictures sorry.

That looks pretty good to me . Only improvement i could suggest is a honeycomb straight after the maf just in case swirl from the turbo makes it's way back that far.

maybe a new Maf, I have a new maf piece coming so 4" maf is in the works too

So I got the Honeycomb you think it should go after the maf?
my only fear there is getting sucked into the turbo :O