[scalbert]

Originally Posted by e90AW335i

Lets just say that someone saw a 18-20psi boost spike at 5500-6000rpm while shifting. This was seen on a boost gauge. Since this is in the upper rpm range doesn't this seem bad for the motor as well as the turbos?

Also, just because you can dial something to make 18psi doesn't mean you should. I honestly think 15.5psi is the max that we should push this turbos too. This is based purely on observing other tuning companys (Alpina (16psi), and Dinan (14psi)).

A momentary spike at a shift would not be an issue. I would prefer it not to happen but it is not too bad.

Keep in mind, 18 PSI at 3k revs is less stressful on the turbos than 13 PSI at 6k revs. The reason most companies don't turn this way is that they would end with a very downward sloping turque curve which is contrary to typical BMW's.

[e90AW335i]

Originally Posted by scalbert

A momentary spike at a shift would not be an issue. I would prefer it not to happen but it is not too bad.

Keep in mind, 18 PSI at 3k revs is less stressful on the turbos than 13 PSI at 6k revs. The reason most companies don't turn this way is that they would end with a very downward sloping turque curve which is contrary to typical BMW's.

Okay, another follow up question. When a person sees a spike at the shift on the boost gauge, lets call it 18 - 20psi, does that mean the turbos just put out 18 - 20psi or does it just mean that amount of air built up while the turbo were pushing 12psi?

[Alex@AKMotorwerk]

Originally Posted by scalbert

A momentary spike at a shift would not be an issue. I would prefer it not to happen but it is not too bad.

Keep in mind, 18 PSI at 3k revs is less stressful on the turbos than 13 PSI at 6k revs. The reason most companies don't turn this way is that they would end with a very downward sloping turque curve which is contrary to typical BMW's.

i get this momentary spike with my Helix Attache between shifts... I've hit as high as 16.5 when letting off the gas. Highest boost i've seen for any steady amount of time was 14.9. My VEI gauge freaks me out because it has the "highest boost" recall feature button. When i hit it the first few times, it told me my boost was 16. I had to watch it while actually driving to see that it was only spiking when letting off the gas between shifts. Also noticed since i installed my Forge DV's with the yellow springs that it spikes a bit higher about 16.5... does this sound normal? I don't believe it's doing any harm to my car since i'm not on the throttle when the boost is that high, i could be wrong tho

[getInline]

Originally Posted by Panoz

Ι've temporary installed a boost gauge (in bar ) to check how was working (used the vacum lines at the left side of the engine that goes to div.valves).

Ahh, I see, thanks, that explains it. I imagine V3 will give you the same results with the same guage tested in the same way.

[BmwFanFL]

Originally Posted by Panoz

Ι've temporary installed a boost gauge (in bar ) to check how was working (used the vacum lines at the left side of the engine that goes to div.valves).

I had a co-driver checking it an commenting all the time how it was behaving.
It was really stable.

The discussion here is not about JB2HR vs V3....

I was just seeing v3 boosting 15,2 to 15,5 continiously and I piss my pants. Scalbert was kind enough to explain me that the Pde reader is showing higher boost than normal...so I'm a bit reliefed now (until placing a boost gauge in psi)

Panoz,

1 bar = 14.5 pounds per square inch

What does the boost gauge show -- do you see the offset mentioned here?

[scalbert]

Originally Posted by e90AW335i

Okay, another follow up question. When a person sees a spike at the shift on the boost gauge, lets call it 18 - 20psi, does that mean the turbos just put out 18 - 20psi or does it just mean that amount of air built up while the turbo were pushing 12psi?

Yes and no. If the throttle is open then the turbos are pushing sufficent CFM to create that boost. However, if this is only momentary then there could be valve phasing aspects occuring which is helping.

[Panoz]

Originally Posted by BmwFanny

Panoz,

1 bar = 14.5 pounds per square inch

What does the boost gauge show -- do you see the offset mentioned here?

Actualy ...1 bar = 14,7psi.

I will need to install it and have a passenger to cross-check laptop & gauge...i see no other solution than this.

[lucassilva]

Would the diverter valves affect boost levels in any way?

Originally Posted by nj323ci

Also noticed since i installed my Forge DV's with the yellow springs that it spikes a bit higher about 16.5... does this sound normal? I don't believe it's doing any harm to my car since i'm not on the throttle when the boost is that high, i could be wrong tho

[Alex@AKMotorwerk]

Originally Posted by lucassilva

Would the diverter valves affect boost levels in any way?

i'm not sure, that was my question... maybe the stronger yellow springs are holding boost for a bit longer before releasing it???

[scalbert]

Originally Posted by lucassilva

Would the diverter valves affect boost levels in any way?

Not the on throttle maximum boost levels. However, if they open slower it would affect the values seen in the PROcede logs when lifting off the throttle.

[Alex@AKMotorwerk]

Originally Posted by scalbert

Not the on throttle maximum boost levels. However, if they open slower it would affect the values seen in the PROcede logs when lifting off the throttle.

would this affect what my boost gauge shows if i'm tapped off before going to the DV's? Also, is this damaging to the turbos/engine at all?
Thanks

[scalbert]

Originally Posted by nj323ci

would this affect what my boost gauge shows if i'm tapped off before going to the DV's? Also, is this damaging to the turbos/engine at all?
Thanks

Nope, you are golden.

[Alex@AKMotorwerk]

Originally Posted by scalbert

Nope, you are golden.

nice, thanks for the confirmation on that.. i'll sleep a lot better tonight!

[remydlc]

since we are talking boost spikes with procede, and we have our best man in the thread (Scarlbert of course). I am going to ask a question, similar to what e90aw335 asked:

Yesterday I saw 20 PSI on my gauge, it held up for way over a second, so long that I realized it and let off the gas, so I dont think it was an spike, and it if was then it was a hell of an spike. I was able to replicate the same, it happened when shifted to 4th gear and went at full throttle. I usually see spikes of 16.x, it happen so fast that you gotta stare at the gauge to see it, this time wasnt so fast. Other than that, boost are steady to 14.5-.7.

I sent a pm to Shiv today, but he hasnt reply, not that i am expecting his reply on a sunday. My settings is V2 @ 92%, planning to lower it to 90% or lower.

TIA

[scalbert]

Originally Posted by remydlc

since we are talking boost spikes with procede, and we have our best man in the thread (Scarlbert of course). I am going to ask a question, similar to what e90aw335 asked:

Yesterday I saw 20 PSI on my gauge, it held up for way over a second, so long that I realized it and let off the gas, so I dont think it was an spike, and it if was then it was a hell of an spike. I was able to replicate the same, it happened when shifted to 4th gear and went at full throttle. I usually see spikes of 16.x, it happen so fast that you gotta stare at the gauge to see it, this time wasnt so fast. Other than that, boost are steady to 14.5-.7.

I sent a pm to Shiv today, but he hasnt reply, not that i am expecting his reply on a sunday. My settings is V2 @ 92%, planning to lower it to 90% or lower.

TIA

V2 can do that. Lower the UT values until it no longer occurs. In addition, the warmer weather may aid this occurance further.

[BmwFanFL]

Originally Posted by Panoz

Actualy ...1 bar = 14,7psi.

I will need to install it and have a passenger to cross-check laptop & gauge...i see no other solution than this.

Close..

Actually, atmospheric pressure at sea level is 1.013 bar, therefore, 14.7 psi (approx numbers). 1 bar is defined as 14.504 psi.

It is possible automotive definitions adjust 1 bar to atmospheric sea level, but that would seem odd if they don't use the physical definition of the unit. There is a related term, "atm" which refers to atmospheric pressure and is often, incorrectly, used interchangeably with "bar."

Regards....

[sflgator]

Originally Posted by remydlc

since we are talking boost spikes with procede, and we have our best man in the thread (Scarlbert of course). I am going to ask a question, similar to what e90aw335 asked:

Yesterday I saw 20 PSI on my gauge, it held up for way over a second, so long that I realized it and let off the gas, so I dont think it was an spike, and it if was then it was a hell of an spike. I was able to replicate the same, it happened when shifted to 4th gear and went at full throttle. I usually see spikes of 16.x, it happen so fast that you gotta stare at the gauge to see it, this time wasnt so fast. Other than that, boost are steady to 14.5-.7.

I sent a pm to Shiv today, but he hasnt reply, not that i am expecting his reply on a sunday. My settings is V2 @ 92%, planning to lower it to 90% or lower.

TIA

If you're planning on keeping your car for a while or if you're getting another 335i in the next ~2 years or so, then you should just upgrade to v3.

[remydlc]

Originally Posted by scalbert

V2 can do that. Lower the UT values until it no longer occurs. In addition, the warmer weather may aid this occurance further.

Thanks Scarlbert, we are fortunate to have you around. I am going to try lowering 2% at a time. I got scare when i saw that. I am punishing my car a lot lately, and enjoining it so much.

You've got a pm too. please take your time, and reply me whenever you can.

Originally Posted by sflgator

If you're planning on keeping your car for a while or if you're getting another 335i in the next ~2 years or so, then you should just upgrade to v3.

I think I am, The N54 engine and its successors are the engine to embrace, with so little effort you get a hell of a car.