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Rev Works turbo kit 2k mile update
I just turned over 2000 miles with the turbo installed, so I figured I'd give you all a brief update.
The tuning is 95% complete at this point, and the car is making great power (260whp on a mustang @ 7psi). There is one issue remaining, which i'll detail in a minute. The guys at the shop are continuing to make improvements to the kit as we learn, and one of those will be a new charge pipe with relocated MAF going on next week, that should improve the stability of the MAF output. The initial design put the sensor a bit too close to the diameter change. Once this is on... we'll move on to solving the last bugging tuning issue: Stalling. This car is driving me nuts for this reason alone. It's extremely weird behavior. Here's my best description: - You know how when you cold start your car it idles kinda high for a few seconds than settles down? well, mine runs super rich and has to maintain super high load to keep idling, and even the rpms dip to ~500rpm. - immediately after it settles down, the car will hunt up and down a couple hundred rpms for about 30 seconds to a minute, then settle into a perfect idle and run great. - now the weird part: if you drive away (or even give it any throttle) before the hunting bit is complete, the car will stall repeatedly when you come to a stop and run like crap until you key it off/on and start the process over. if you wait until the hunting is complete (a minute or so after starting the car initially), everything runs perfect and the car never stalls. it's a beast. I've been pouring over logs for weeks trying to figure out what the switch is that is causing this distinct change in behavior. I have a number of theories, probably none of which are 100% correct. But it's very clear: if you pull away to soon, it stalls and runs like poo. if you don't, it doesn't. Any ideas? Beyond that everything is great. The kit is holding up great. No cracks, leaks, etc. I've recently added a Motiv overpipe and will be turning up the boost once the MAF pipe upgrade is finished. I can't wait! :burnrubber: |
A nice update, great that you are enjoying you car.
I'm no expert in tuning but these symptoms are really weird ! I guess when you pull away while it's hunting within the rough idle the car sticks with that idle issue ? I'm no expert that's just a random ass guess, nevertheless keep on enjoying it Sent from my phone :) |
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I do and am tuned to idle at 900-700, it got rid of my weird hunting issues. As a reference before I lightweighted my drive train I was idling between 700-600 ish. As reference I have LWCP, LW flywheel, CF drive shaft, and 15.4lb wedsports. |
It does have an act streetlite flywheel. The idle, when it's settled, is around 900rpm. They raised it to accommodate the flywheel when the clutch was installed I believe.
@mad_sb have you found anything in your investigation into the ecu that may help understand what's going on? |
Maybe the cams need to settle in to their adjustments or initial settings. I read here that someone always let their car idle after starting to allow the cams to do their things.
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I'm not forced induction so I have no right to chime in here, but my car exhibits the same behavior NA. Even if I started out after that first large RPM drop, the car would have really large trims, high load, stall if I came to quick stops and generally run like hell for an extended duration even after coming fully up to temp. Letting it warm up to the first notch above bottom before proceeding and it's fine every time. I know you're aware that fixes it, just thought I'd mention it may not be related to your specific configuration. I too remember reading the post about the cam angles adjusting themselves at startup, but wasn't that only for post-reflash, or are they always seeking initially? At least in my logs, I don't see the intake/exhaust angles moving around much from startup to warm.
Apologies if this isn't useful or germane to topic. Thanks for the update, and hope you find a resolution! |
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Random question but do you have all the OEM patches installed in your tune? Your NA problem sounds like one I had before moto-mike updated me with the new patches. |
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These symptoms don't make any sense to me. I have had my fair share of stalling problems from my Tial Q BOV opening at idle to the car stalling when I would put the clutch in and let the RPM drop at speed, but never any kind of issue like that.
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I noticed today that if I get in and drive away immediately and can manage to not stall it (generally by not coming to a stop) in the first few minutes it'll almost go back to normal, not stalling anymore, but still hunting when I eventually do stop. If I wait 20-30 seconds for it to stop hunting then, it'll be perfectly fine thereafter. I'm stumped, but it definitely seems like some ecu routine getting interrupted by my driving too soon. |
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Maybe does this have something to do with mad_sb's theory on the overly extended cold loop? I don't see how it would, as the trimmings normalize afterwards, just postulating out loud that perhaps there are other systems staying in an altered state for too long as well. Anything notably different in timing advance or cam angles from cold to warm idle? Mine seem to be more or less unchanged. Only variabls I'm seeing with any kind of delta are the trims, but I'm a newbie to all this. |
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I read somewhere that when our cars start cold, the ECU is in closed, or open-loop, and after it warms up a little it goes to open, or closed-loop (not sure which), and I wonder if maybe by not letting the car complete that changeover it's doing what your cars are doing?
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Open loop when cold, closed once warmed up. This was my thinking as well. On normal vehicles, there are triggers (various temperature sensors) that'll switch it over. I just remember mad_sb saying that our cars run in open loop way too long I believe. I'm just wondering...if it's running pigrich, it's not taking in the air volume expected. Intake cam angle or throttle open % change, idle to idle?
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i've observed the switch from open loop to closed loop on cold start. this is the exact moment that the load goes from crazy high (80+%) to normal (20-30%) and the idle settles down. the hunting up and down bit happens in closed loop after the switch.
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Can you post a log up from cold start. Curious to see a few things, timing, air fuel ratio, commanded cam timing, as well as trims when it switches over into closed loop.
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sounds like someone dinked with a table they didnt have to cause on all the cars ive tuned so far have yet to come across anything like this. sounds also like you maf scaling is off. you should have that much issue dialing in these setups. i spend more time building and adjusting ignition values while fine tuning than anything else.
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this may be completely incorrect, but maybe something is possibly making your car go through a throttle body relearn procedure every time you start the car? I know this is a common issue with DBW toyotas after changing the battery.
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When you refer to "load", what are you talking about here? I'm still learning about our fuel injection systems. I still don't know what "trims" are either.
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At very high rpm with the throttle barely open there is very low load. At low rpm, wide open throttle load is very high. Think of it as a measurement of how much work you're asking the engine to do. Trims are offsets that the ecu applies to the base fuel tables based on sensor feedback. These are 'learned' or cached over time. High trims are bad. |
So how is there any load at idle? You said your load goes from high/80% to low when the idle settles. Trying to grasp/visualize this.
Thanks for explaining. |
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Maybe it's something tied to the warm up phase. I'm guessing you're on pump not 85?
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@JuniorAWD any thoughts?
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Happened to me. Was extremely aggrevating.. Installed stiffer spring in the BOV and fixed my issue
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i'm embarassed to admit that the stalling issue has been solved by adding another spring to the turbosmart bov. this is an issue i've solved in the past so it's pretty deflating to have it bite you in the ass again lol. the bov was just ever so slightly open at idle, not enough to see or hear air moving, but enough to cause the stalling. the spring that comes in the race port is meant for 15-18inHg, my car pulls 20-22. oh well, at least it's fixed!
the 'hunting' when you start the car is still there. that seems to be a separate issue. |
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