lets talk about turbo lag

jokergerm · 10-20-2010, 12:10 AM

Ok so i have been reading about turbo lag and im not sure if i have it
I have a 07 335i with jb3 2.0 and a boost gauge

At 2k rpm in 4th gear i am making about 1lb boost crusing. If i floor the car, it the boost jumps instanly to 5 psi and by 2500 rpm i and at 10 psi and then the car takes off like a raped date and tops out at about 14.5 psi

Is that normal or am i having lag and boost should build lower in the RPMs?

jokergerm · 10-20-2010, 02:55 PM

Anyone ?

73 views and nothing

Jeff@TopGearSolutions · 10-20-2010, 03:04 PM

What kind of gauge are you using to read boost....

What other modifications are done to the car.

My boost jump instantly to 17 PSI from almost any gear any RPM.

You should be able to build boost at low RPM on this car.

jokergerm · 10-20-2010, 04:35 PM

I am stock with a INATKE and JB3 on map 5

Like i said i can start building boost at low RPM but it does not start to come alive until about 3k rpm.

When rolling arond in 4th gear at say 40 MPH, my digital boost gauge reads like 1 psi and if i floor it the boost jumps to about 5 and slowly accelerates and then at about 2500 the boost is up around 14psi and at 3k the car starts to pull super hard

But from 1000 rpm to close to 3000 rpm the car is not quick

Jeff@TopGearSolutions · 10-20-2010, 05:03 PM

Quote:

Originally Posted by jokergerm

I am stock with a INATKE and JB3 on map 5

Like i said i can start building boost at low RPM but it does not start to come alive until about 3k rpm.

When rolling arond in 4th gear at say 40 MPH, my digital boost gauge reads like 1 psi and if i floor it the boost jumps to about 5 and slowly accelerates and then at about 2500 the boost is up around 14psi and at 3k the car starts to pull super hard

But from 1000 rpm to close to 3000 rpm the car is not quick

well driving around at 4th gear at 1000 rPM I wouldnt expect performance to be some seat of the pants thing. So I think your fine.

This car doesnt really hit its sweet spot till the 4500 RPM range.

jokergerm · 10-20-2010, 05:08 PM

So what is the definition of Turbo Lag?

FVM3 · 10-20-2010, 05:10 PM

Quote:

Originally Posted by jokergerm

So what is the definition of Turbo Lag?

means it takes some time to "switch on" the turbo, doesnt act like a N/A car,

jokergerm · 10-20-2010, 05:16 PM

Ok lets try this,

How many RPM are you guys at before you see over 10psi boost?

Maybe that will help my brian understand this better

and what RPM are you seeing peak full boost

slowSwede · 10-20-2010, 06:36 PM

I'd say turbo lag is from the time you stomp the throttle until the time the car get's going.
In a NA car, it just starts going at once.
Sure, NA cars also have their sweet spots, but they do react in almost any RPM range.

Newer turbo cars have no big turbo lag to speak of. Go drive an evo or sti from 2007 at 2000 rpm in 4th, stomp the throttle and you'll know what turbo lag is for sure.

If you have turbos you have turbo lag, that's sort of hard to get around.
If you have a 335, you don't have a lot of it though.

shortseller · 10-20-2010, 06:45 PM

Quote:

Originally Posted by jokergerm

So what is the definition of Turbo Lag?

Q: How does that "lag" feel, anyway? How can I reproduce it?

A: Go in 4th gear (or M4 with steptronic) at ~1500 RPM, then depress throttle halfway. If you feel a second rush of acceleration only when RPM reaches 3000 after ~0.5 seconds, you are experiencing lag, since full torque is supposed to be present from ~1400 RPM already.

jokergerm · 10-20-2010, 07:04 PM

If full torque is made at 1400rpm, what should the boost be at full torque at 1400 rpm? Cause at 1400 RPM my car is a snail and they 3000 comes around and you better hold on

16M4 · 10-20-2010, 11:25 PM

OP, you ask stupid questions...
You claimed that you've done your research (in your other thread), but obviously you have not.

07'335iAlpine · 10-20-2010, 11:33 PM

Quote:

Originally Posted by Alfred

OP, you ask stupid questions...
You claimed that you've done your research (in your other thread), but obviously you have not.

agreed...

jokergerm · 10-20-2010, 11:59 PM

Sorry i am a NEWB. I have tried searches and not gotten what i was looking for.

Just trying to learn here.

Sorry for wasting your guys time.

stren · 10-21-2010, 12:20 AM

turbo lag is to do with the *time* delay from when you stomp on the pedal to when the max torque available at the current rpm hits. It does not mean you can't acheive a certain amount of boost at an rpm. You may be getting confused because during this time you'll be accelerating and you're no longer at the same rpm anymore so you think that XXpsi at 2000rpm is unachievable but that's because by the time the lag period is over you're no longer at 2000rpm.

Turbo lag is due to the interactive nature of the turbo and engine. If the engine isn't producing enough exhaust to turn the turbine quickly then you can't achieve high boost until it does produce enough exhaust gas pressure. It just happens more at low rpm because there is generally "less" exhaust

AlterZgo · 10-21-2010, 12:56 AM

Your car has turbo lag, but ALL turbocharged cars have this. Hitting 10 psi of boost at 2500 rpm is fine. Nothing's wrong w/ your car.

The 335 has significantly less turbo lag than other turbocharged cars in the past, but it still has it. I would describe it more like a soft throttle response. On a NA car, when you hit the gas, there's instant acceleration. In the 335, when you hit the gas, it feels slightly delayed... like the throttle is a bit soft in responding. That's turbo lag. Still, much better than in the past where you'd have to count 1-1000, 2-1000, 3- BAM car slingshots ahead like crazy.

10-20-2010, 12:10 AM	#1
jokergerm Lieutenant 127 Rep 571 Posts Drives: 2015 M6 GC Join Date: Oct 2010 Location: seattle iTrader: (0)	lets talk about turbo lag Ok so i have been reading about turbo lag and im not sure if i have it I have a 07 335i with jb3 2.0 and a boost gauge At 2k rpm in 4th gear i am making about 1lb boost crusing. If i floor the car, it the boost jumps instanly to 5 psi and by 2500 rpm i and at 10 psi and then the car takes off like a raped date and tops out at about 14.5 psi Is that normal or am i having lag and boost should build lower in the RPMs?
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10-20-2010, 02:55 PM	#2
jokergerm Lieutenant 127 Rep 571 Posts Drives: 2015 M6 GC Join Date: Oct 2010 Location: seattle iTrader: (0)	Anyone ? 73 views and nothing
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10-20-2010, 03:04 PM	#3
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	What kind of gauge are you using to read boost.... What other modifications are done to the car. My boost jump instantly to 17 PSI from almost any gear any RPM. You should be able to build boost at low RPM on this car.
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10-20-2010, 04:35 PM	#4
jokergerm Lieutenant 127 Rep 571 Posts Drives: 2015 M6 GC Join Date: Oct 2010 Location: seattle iTrader: (0)	I am stock with a INATKE and JB3 on map 5 Like i said i can start building boost at low RPM but it does not start to come alive until about 3k rpm. When rolling arond in 4th gear at say 40 MPH, my digital boost gauge reads like 1 psi and if i floor it the boost jumps to about 5 and slowly accelerates and then at about 2500 the boost is up around 14psi and at 3k the car starts to pull super hard But from 1000 rpm to close to 3000 rpm the car is not quick
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10-20-2010, 05:08 PM	#6
jokergerm Lieutenant 127 Rep 571 Posts Drives: 2015 M6 GC Join Date: Oct 2010 Location: seattle iTrader: (0)	So what is the definition of Turbo Lag?
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10-20-2010, 05:16 PM	#8
jokergerm Lieutenant 127 Rep 571 Posts Drives: 2015 M6 GC Join Date: Oct 2010 Location: seattle iTrader: (0)	Ok lets try this, How many RPM are you guys at before you see over 10psi boost? Maybe that will help my brian understand this better and what RPM are you seeing peak full boost
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10-20-2010, 06:36 PM	#9
slowSwede Lieutenant 21 Rep 549 Posts Drives: 335 coupe Join Date: Jan 2010 Location: Skåne iTrader: (0)	I'd say turbo lag is from the time you stomp the throttle until the time the car get's going. In a NA car, it just starts going at once. Sure, NA cars also have their sweet spots, but they do react in almost any RPM range. Newer turbo cars have no big turbo lag to speak of. Go drive an evo or sti from 2007 at 2000 rpm in 4th, stomp the throttle and you'll know what turbo lag is for sure. If you have turbos you have turbo lag, that's sort of hard to get around. If you have a 335, you don't have a lot of it though.
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10-20-2010, 07:04 PM	#11
jokergerm Lieutenant 127 Rep 571 Posts Drives: 2015 M6 GC Join Date: Oct 2010 Location: seattle iTrader: (0)	If full torque is made at 1400rpm, what should the boost be at full torque at 1400 rpm? Cause at 1400 RPM my car is a snail and they 3000 comes around and you better hold on
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10-20-2010, 11:25 PM	#12
16M4 Colonel 131 Rep 2,978 Posts Drives: 2016 SO M4 Join Date: Mar 2010 Location: Broomfiled, CO iTrader: (5)	OP, you ask stupid questions... You claimed that you've done your research (in your other thread), but obviously you have not.
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10-20-2010, 11:59 PM	#14
jokergerm Lieutenant 127 Rep 571 Posts Drives: 2015 M6 GC Join Date: Oct 2010 Location: seattle iTrader: (0)	Sorry i am a NEWB. I have tried searches and not gotten what i was looking for. Just trying to learn here. Sorry for wasting your guys time.
	Appreciate 0 Quote

10-21-2010, 12:20 AM	#15
stren Second Lieutenant 169 Rep 252 Posts Drives: 335i Join Date: Apr 2010 Location: SD, CA iTrader: (0)	turbo lag is to do with the time delay from when you stomp on the pedal to when the max torque available at the current rpm hits. It does not mean you can't acheive a certain amount of boost at an rpm. You may be getting confused because during this time you'll be accelerating and you're no longer at the same rpm anymore so you think that XXpsi at 2000rpm is unachievable but that's because by the time the lag period is over you're no longer at 2000rpm. Turbo lag is due to the interactive nature of the turbo and engine. If the engine isn't producing enough exhaust to turn the turbine quickly then you can't achieve high boost until it does produce enough exhaust gas pressure. It just happens more at low rpm because there is generally "less" exhaust
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10-21-2010, 12:56 AM	#16
AlterZgo Lieutenant Colonel 1538 Rep 1,665 Posts Drives: 23 X3 M40i, 21 911S, 24 Taycan Join Date: Sep 2010 Location: Gilbert, AZ iTrader: (0)	Your car has turbo lag, but ALL turbocharged cars have this. Hitting 10 psi of boost at 2500 rpm is fine. Nothing's wrong w/ your car. The 335 has significantly less turbo lag than other turbocharged cars in the past, but it still has it. I would describe it more like a soft throttle response. On a NA car, when you hit the gas, there's instant acceleration. In the 335, when you hit the gas, it feels slightly delayed... like the throttle is a bit soft in responding. That's turbo lag. Still, much better than in the past where you'd have to count 1-1000, 2-1000, 3- BAM car slingshots ahead like crazy.
	Appreciate 0 Quote