rich on turbo

smidge

smidge

Small Car Enthusiast
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wideband is telling me some interesting thing, one is that my mixtures are pretty good on boost on the supercharger, but once it changes over to the turbo, they go bulk rich (10:1 or higher)

anyone know why this might be happening? leak somewhere? busted turbo?

any clues would be great
 
smidge said:
wideband is telling me some interesting thing, one is that my mixtures are pretty good on boost on the supercharger, but once it changes over to the turbo, they go bulk rich (10:1 or higher)

anyone know why this might be happening? leak somewhere? busted turbo?

any clues would be great
Click to expand...

I fairly sure they run slightly rich up high standard there is a lot of power to be made leaning it out there.Could be the FMIC But I'm not to sure.How 's the afr at idle man?
 
afrs at idle are right on stoich, hovers around 14.7...

to be honest the ratios look pretty good far as i can tell without logging them against TPS and RPM signals, its just on the turbo it noticeably doesn't pull any harder and the ratio drops right down to off the scale
 
i would expect it to go a little rich up there, but its the same amount of boost as with the S/C, sure maybe a little more airflow as well and a few more revs but its a massive change in ratio

will get some graphs up soon as i get the logging going on my wideband
 
smidge

but if you,ve got, say, 50hp at s/c revs and 100+hp at full chat, that,s a lot more heat output to dissipate ?
 
i guess so, it feels a little held back up there tho..

hmm further investigation required!
 
guess i need to know 100% every system (vacs, solenoids etc) is working perfectly before i mess with the computer...

running bulk rich is pretty bad for an engine anyway, so i need to bring it back some... gains i don't care about, just want reliability and the go its meant to have..

baz's car sounds angry on the turbo, mine sound pooncy :D
 
smidge said:
guess i need to know 100% every system (vacs, solenoids etc) is working perfectly before i mess with the computer...

running bulk rich is pretty bad for an engine anyway, so i need to bring it back some... gains i don't care about, just want reliability and the go its meant to have..

baz's car sounds angry on the turbo, mine sound pooncy :D
Click to expand...

Ha ha that the standard fueling for you that was low boost aswell!

frank said:
smidge

yes, i bet you would see gains by leaning it off some, how brave are you tho ? :D
Click to expand...

It's just a matter of getting a knock sensor bolted to the block and getting it mapped with what ever Ecu is being put in to it.Mine was mapped on a good old Dyno dynamics ha ha
 
smidge said:
ah right thats the one, short memory sorry i forgot!
Click to expand...

http://www.rhdjapan.com/jdm-low/TRUST-E-Manage-Main-Unit-16779

http://www.rhdjapan.com/jdm-low/TRUST-E-Manage-Optional-Injector-Harness-16780

http://www.rhdjapan.com/jdm-low/TRUST-E-Manage-Optional-Ignition-Harness-16781

http://www.rhdjapan.com/jdm-low/TRUST-E-Manage-3-0bar-Boost-Pressure-Sensor-16782

http://www.rhdjapan.com/jdm-low/TRUST-E-Manage-Boost-Pressure-Sensor-Harness-18317

As Far as I remember I was short the injector harness when Ed was fitting mine and There's only two wires used on the ignition harness so the rest can be used as an injector harness but obviously the colour coding will be different so care must be taken
 
Blimey i missed this thread....

Firstly I am not surprised at all, given the improvements you have made to your engine, and I suspect running more boost than stock.

Here is a stock fuel map:

stfuelmap.jpg

The values are approx AFR. As you can see its mapped very rich at the far end. You are now entering this area, basically as I already said your car needs remapping.

Anything below approx 11.5AFR is a total waste and loss of power on your spec.

Smidge send me a pm if you want, I may be able to help you :)

Ed
 
frank said:
it has to go mad rich at high rev,s, to stop the piston,s and exhaust valve,s melting surely ?
Click to expand...

No not at all. Were talking relatively low power really in real terms, even at 300bhp/L I wouldn't map that rich.
 
Ed, i actually suspect its running lean cause its not making enough boost, i'm no expert on boost control but as the ECU has no idea as to what boost is running, it can't control or or change it etc

until today i had 10psi on the supercharger and about 13 on the turbo

with the addition of a small bleed valve on the turbo actuator line i get a strong 15psi on the turbo at high load in 4th, and a noticable seat push that wasn't there before

now if i could get the supercharger up a few psi, perhaps the same way baz did then i'm getting close i reckon, according to the wideband i'm still a little rich, but with 15psi it hangs closer to 11 than 10 which is good i reckon, no audible pinging either.. i guess the FMIC is helping in that area too, there's a lot more air space to fill so a few extra PSI of boost should wake it up a little
 
Unless you run REALLY lean it will have no affect on boost, lack of boost will only happen with extreme loss of power due to an overly lean condition, were talking AFRS 16:1+.

ECU doesn't need to know what boost you are running. It only needs to know the amount of air and its density entering the engine. This is measured directly via the AFM. Its output correlates exactly to the amount of air MASS entering the engine and therefore the load under which it is operating.

FYI the stock ECU has a load cut limit on it. You are not even close to that so I wouldn't worry at all.

Take what I say how you wish, but if your displaying anything 10.xx afr you are way too rich and wasting a huge amount of fuel and also sacfacising power, not to mention the life of your engine due to accelerated ring land wear.

Regardless a ST never needs to be richer than 11.5:1. Theoritical maximum power will be made at 12.8:1, reality is more like 12:1 depending on the combusion efficiency of the engine. I used to run mine around 11.8-12:1 when running around 190bhp, then nitrous on top with the same AFR.

Off boost I would keep it as much to 14.7:1 as possible, and infact could achieve 40mpg+ if driven carefully.
 
thats good to know thanks Ed! Did you leave your timing at +15 when running that kind of power? i have mixed feelings about using a 2d controller (which i can get for free basically if i build it)

apart from full load the AFR's are pretty much spot on, it jumps into lean cruise 14.8 or so whenever at light throttle and off boost, on the SC it heads to around 12-13afr and then at full noise it IS way rich, and yes i haven't been hitting full noise too much as i understand a really rich state can break things

i'd be quite happy to map it myself but i'm still a little hesitant as i don't have a spare engine in the shed should i break something
 
I completely remapped my ECU, and no I didn't use stock base timing.

Get an S-AFC, it will do the job just fine. Just trim the top end where you get excessively rich. Its very straight forward.
 
That looks fine. 128 is serious over kill even 16 points would be more than enough, but it will fix your problem without a remap.
 

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