Surge killing turbos
- Thread starter DCT_JAY
- Start date
Check the throttle sensitivity . With high torque low rpm you can actually feel the flywheel and it can cause car to move and your foot to move very small amounts and with no filtering ,well you get the idea .
You got it . When you are at boost threshold and the tune base wgdc isn't dead on the pid algorithm goes wonky cause you have a bov throwing a variable into the mix.
Hey, I didn’t know this. News to me. Something to keep in mind. EDIT: (This is a great thread.)
This is my experience too. 10psi spring seems to snap shut faster and I get better response when driving sportily.
This was also my experience. The 10psi “plain” spring seems more responsive than the 8psi “white” spring.
But now I’m noticing for the first time “chugging” or “lugging” at low rpm (below 1500 rpm) in 3, 4, or 5th gear going uphill. I’m not sure if this is due to BOV / spring or something else. Thoughts?
(One other thing to consider is whether the low rpm lugging up hill is a result of the transmission tune. I had recently flashed xHP Stage 3 V2.1, upgrading from Stage 3 V2.0. It kind of surprised me that the tranny was shifting up under low torque request below 1500 rpm...:headscratcher
The chugging you experience is tune related. I don't think it is xhp or BOV. BOV works correctly with whatever your engine is doing or not. I don't think it is the cause of the chugging sensation.
My car does the same regardless of the spring rates. Low rpm midpower acceleration to sudden high power acceleration results in lugging the engine and slow response. You have to be mondful when you want to accelerate quickly. Make sure you are not in the lugging range.
This is also possibly on the mark as I had updated the throttle tables (zeroed out) to make the engine more responsive. So I’m lugging it most likely. The simplest thing to do will be to flash my previous tune that had the stock throttle tables and see if I still get that low rpm lugging. Stay tuned!
Yeah with a light weight flywheel and single turbo I shift at 2k as well I always keep it above 2k regardless of grade. No reason to lug it at 1k rpms which is my idle rpms.
Not to mention 300 hp at 1500 Is like 600 at 3000 on rods so if you manage to hit 400 that's like 800 . I would think that's why 700 to 800 at 3500 rpm Is the magical bend a rod number, bmw built in margin and since it's a midrange engine stock it can handle tons of power up top. But that's also why stock turbos can bend rods no prob , obviously I realize it's not as simple as double rpm double the force , in some ways it's worse cause usually increases at delta but also inertia and momentum play a roll as well .
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It's cylinder pressure that buckles rods. Cylinder pressure at 500 ft lbs and 1500 rpm is very similar to cylinder pressure at 500 ft lbs and 6000 rpm. There is more to it than measured torque though, an engine has many different forces on it as it operates, and one big one that people often forget about is inertial loads. Where we're concerned, inertial loads put rods in tension, offsetting a portion of the gas force. If you revved the engine high enough it would offset all of the force. Torque is torque regardless of RPM, but the higher you rev the engine the more torque (increased cylinder pressure via increased boost, timing, or both) you can add before rod buckling becomes an issue (tuning and flow aside). There are, of course, other issues to deal with when revs are raised, but that's it in a nutshell.
Relatedly, when choosing a platform to take a (stock) NA motor and decide to turbo it... if that NA engine has a very high RPM limit, it'll probably hold up to being boosted well. It was built for those high inertial loads. BMW S65 or Honda S2000 for example.
Chris
Relatedly, when choosing a platform to take a (stock) NA motor and decide to turbo it... if that NA engine has a very high RPM limit, it'll probably hold up to being boosted well. It was built for those high inertial loads. BMW S65 or Honda S2000 for example.
Chris
Insert hp where i wrote tq was doing it from work and not paying attention I meant 200 hp at 2g Is like 600 at 6 and so on
Valves cover was cracked so I replaced it and it defiantly feels better, now I have this strange squiggle and my fuel trims just bombing out. Any ideas ?
Valves cover was cracked so I replaced it and it defiantly feels better, now I have this strange squiggle and my fuel trims just bombing out. Any ideas ?
Only thing I think I see is the wgdc. Looks like it may have been tuned with that VC leak. Now that it's gone it's hunting. WG needs some help.
I don't see anything else that stands out or looks abnormal enough for concern.
Shot my tuner a E-mail, i will update any changes with the updated tune if he sends me one.
Does the Vader Solutions adapter fall into the "do not use" group?
I'm running it right with GCLITES, tial bov w/ black spring.
Here is my latest log...boost is very sloppy .
my buddy who runs Rb Twos looked alot like this, told him to check his couplers and sure enough there was one that split on the lower chargepipe coupler.Does the Vader Solutions adapter fall into the "do not use" group?
I'm running it right with GCLITES, tial bov w/ black spring.
Here is my latest log...boost is very sloppy .
Thanks I'll make a note of that. To be clear you mean between cp and fmic outlet?
The shop did a smoke test and only found a small leak by the catch can. They tightened it all up and no more smoke leak but the logs haven't improved by much. It's quite the headache. They claim any leaks would have shown up with the smoke test.
I'm dropping the car off next week so they can really take their time for a closer look.
These are some things to have checked that i hunted down forever since i barley have time to work on my own car.
1. Tmap sensor "O" Ring has split on me 3 times ( ended up switching to a tial and had to get new chargepipe and never happened again) and the bolts that secure the Sensor into the chargepipe can leak. ( Just take them out and put loctite )
2. Cracked Valve cover ( this mf was such a pain in my ass for the longest because i overlooked it)
3. Split outlet boot twice ( Made my own heatshield for it now and dont have that issue anymore)
4. Both intercooler couplers had small holes that most likely a animal knawed and blew a hole under boost later
5. Chargepipe coupler slipped off underneath so you couldnt tell ( Rookie mistake, just tighten it better)
6. Boost solenoids x2 ( didnt have a issue with them just did it out of process of elmination)
7. Injectors replaced with Index "13" (technically just the latest and last updated version of the Index 12's)
Note: none of this happened all at once, just a brief summary of what ive fixed when i was having boost\vaccum leaks through out my ownership.
Does the Vader Solutions adapter fall into the "do not use" group?
I'm running it right with GCLITES, tial bov w/ black spring.
Here is my latest log...boost is very sloppy .
I have no experience with Omar's product, and don't know the specifics of his design in particular, but the concept is fine, provided he has implemented it reasonably I don't see any issue with it.
Chris
I use the Vader adapter and it seems to work fine.Does the Vader Solutions adapter fall into the "do not use" group?
I'm running it right with GCLITES, tial bov w/ black spring.
Here is my latest log...boost is very sloppy .
Thanks Jeff. How does your bov sound? Mine can sound like an owl sometimes, and sometimes it's a clean psssh. I was curious if something was wrong.
