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looks like you will have good average power once you sort that out.

get a piggyback of stand alone ecu to get some more midrange and power and stop it dropping to 10 afr's. what turbo's are you using to run 20psi? n1's ?

Guest Mashrock
would it be tuned for 20psi fuel wise, and the spark is blowing out, causing a snowball effect of less boost and richer fuel ratios?

interesting.

will keep that in mind. but i doubt the spark is going anywhere. its always been set up that high and still goes very well on the street. i'm thinking it was controler problems.

i also still run standard dumps. on r34n1 turbos which have .42 front housing

we were thinking it was the dumps maybe causing problems.

i re setup the boost controler and it appears to hold 1.4 bar on my guage. but how accurate are they.

one would think running more boost would lean the car out.

it's hard to predict what would happen, it depends on what the tuner has done

say it was tuned at 12psi, the regions on the map corresponding to loads when boost is higher than 12psi aren't really touched. The tuner can just leave them, or guestimate, or put in some safe values. So can be hard to predict what would happen here.

Do you have the plot of manifold pressure (boost)?

Edited by MerlinTheHapyPig
Guest Mashrock
it's hard to predict what would happen, it depends on what the tuner has done

say it was tuned at 12psi, the regions on the map corresponding to loads when boost is higher than 12psi aren't really touched. The tuner can just leave them, or guestimate, or put in some safe values. So can be hard to predict what would happen here.

Do you have the plot of manifold pressure (boost)?

Hey manifold pressuer looks alot similar to the afr really haha, i dont have it on me. or not too sure if my mate has it. but it dropped very quickly.

but i do understand where your getting at. but for some reason i dont think it would have been tuned for anything lower than 1 bar.

hmm, interesting

intercooler heat soak can cause the pressure to drop a bit, but probably not as much as you describe. If you have an electronic boost controller, try removing it and wack in a boost control valve (just get one of the cheap ones, thread in forced induction "i found a good cheap boost controller")

it's important when tuning to tune the areas on the map below the corresponding boost level, since 95% of the driving you do, won't be full throttle / full boost.

I'd suggest working out what's wrong with the boost (use manual boost controller, check for vacuum leaks, cooler hose leaks), then re-dyno'ing it and if afr's are still all over the place, re-tune

does boost drop like that when driving it on the street? maybe the fan on the dyno wasn't providing air to the intercooler.

Guest Mashrock
hmm, interesting

intercooler heat soak can cause the pressure to drop a bit, but probably not as much as you describe. If you have an electronic boost controller, try removing it and wack in a boost control valve (just get one of the cheap ones, thread in forced induction "i found a good cheap boost controller")

it's important when tuning to tune the areas on the map below the corresponding boost level, since 95% of the driving you do, won't be full throttle / full boost.

I'd suggest working out what's wrong with the boost (use manual boost controller, check for vacuum leaks, cooler hose leaks), then re-dyno'ing it and if afr's are still all over the place, re-tune

does boost drop like that when driving it on the street? maybe the fan on the dyno wasn't providing air to the intercooler.

i seriously have never noticed boost dropping on the street. but who looks at a guage really. i'll take it back to him now with my instructions on the profec and give it a shot again. then if boost is not an issue i am going to get myself some trust dumps. and then re dyno it again.

the car is really just a track car. i dont drive it that often on the street enough to worry about low boost and this high boost bullshit. i just want to run 1.4 bar. and thats it.

and use 5th gear this time on the dyno :D

now i posted another thread about my exhaust temp sensors. and about them being unplugged. i use fcon pro v. could they only be used during tuning?

Mashrock, the profec is a basic ebc, it uses a signle value gain and single value duty cycle in order to achieve a given boost level.

Some of the higher end ebc's greedy profec e0-1 I believe it is and the avcr, blitz sbc-id learn the boost curve. Essentially it uses a different duty cycle for given parts of the rpm or boost curve to hold stable boost.

If thats not the problem which I doubt it is if you are running a well sized turbo then it may be a boost leak or soemthing silly.

Guest Mashrock
Mashrock, the profec is a basic ebc, it uses a signle value gain and single value duty cycle in order to achieve a given boost level.

Some of the higher end ebc's greedy profec e0-1 I believe it is and the avcr, blitz sbc-id learn the boost curve. Essentially it uses a different duty cycle for given parts of the rpm or boost curve to hold stable boost.

If thats not the problem which I doubt it is if you are running a well sized turbo then it may be a boost leak or soemthing silly.

ah so my controler is not going to hold boost at the level that i want...

or there is going to be a boost leak somewhere?

i'm running 34n1 turbos. but only the .42 front housing size.

Yours may be a different issue but its what I have came across when trying to push turbo's to the limit.

An example is the stock rb20det turbo, mine was unable to hold more than 12.5psi running a bleeder or HKS ebc, I can't remember the model but it was a simply knob duty and gain adjustment type.

I bought the Blitz SBC-id, in Auto mode where it would actively change the duty cycle in order to hold the given boost level I could see on the display how the solanoid was operating, at peak torque it was basically all the way open letting a lot of boost through to the wastegate, the duty cycle here was low, at high rpm the solanoid was almost completely closed in order to hold the given boost level.

Put the sbc-id in to manual mode where you only have the single duty and gain setting it would drop boost.

I was told to grab a decent boost controller by Tim possingham the origional owner of RPM, you may remember him as he's been in a few zoom mag articles and did a well known stock intercooler pressure drop test vs an aftermarket intercooler. He told me not to waste my time with the manual type ebc's and grab a avcr or blitz item if you want to get everything out of your turbo you can.

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